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Enhanced lakebed sediment erosion in Dongting Lake induced by the operation of the Three Gorges Reservoir 认领 引用 被引量：6
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作者 ZHOU Yongqiang LI Jingbao +2 位作者 ZHANG Yunlin ZHANG Xinping LI Xichun 《Journal of Geographical Sciences》 SCIE CSCD 2015年第8期917-929,共13页
Based on field-survey hydrological series in the Dongting Lake watershed from 1951 to 2011, the variations of lakebed sediment siltation/erosion（S/E） regimes of the Dongting Lake after the operation of the Three Gor... Based on field-survey hydrological series in the Dongting Lake watershed from 1951 to 2011, the variations of lakebed sediment siltation/erosion（S/E） regimes of the Dongting Lake after the operation of the Three Gorges Reservoir（TGR） were analyzed. Significantly positive correlations were found between the flow rate from Zhicheng and the Three Outlets（r^2=0.859, p〈0.0001）, and between the flow rate and sediment delivery rate at the Three Outlets（r^2=0.895, p〈0.0001）. This indicated that the flow rate and sediment delivery rate at the Three Outlets were largely determined by the flow rate from the upstream Yangtze River. Sediment deposition amount in the Dongting Lake basin dropped from ＋4796.4×10^4 t during the period before the operation of TGR（1999–2002） to ＋684.1×10^4 t, ＋449.8×10^4 t and –559.6×10^4 t during the impoundment Phases I, II and III of TGR. The S/E regimes changed from a siltation-dominant to an erosion-dominant state under the pre-discharge, water-storage and water-supplement dispatch over the impoundment from Phase I to III. The sediment deposition amount decreased dramatically under the flood-storage dispatch over the impoundment Phase I to III. The estimated annual mean flow rate, sediment delivery rate and sediment concentration thresholds were respectively 970.81 m3/s, 466.82 kg/s and 0.481 kg/m3 for the upstream Three Outlets to maintain an erosion-dominant state in the downstream linked the Dongting Lake. 展开更多
关键词 The Three Outlets The Three Gorges Reservoir （TGR） flow rate sediment delivery rate DongtingLake
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Effects of the dispatch modes of the Three Gorges Reservoir on the water regimes in the Dongting Lake area in typical years 认领 引用 被引量：15
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作者 OU Chaomin LI Jingbao +3 位作者 ZHANG Zhaoqing LI Xichun YU Guo LIAO Xiaohong 《Journal of Geographical Sciences》 SCIE CSCD 2012年第4期594-608,共15页
Based on the field-survey prototype hydrology data in typical years, the effect during the running periods of different dispatch modes of the Three Gorges Reservoir on the water regimes in Dongting Lake area is compar... Based on the field-survey prototype hydrology data in typical years, the effect during the running periods of different dispatch modes of the Three Gorges Reservoir on the water regimes in Dongting Lake area is comparatively analyzed. The results are shown as follows. （1） The influence periods are from 25 May to 10 June, from 1 July to 31 August, from 15 September to 31 October and from December to the next April, among which the influence of the water-supplement dispatch in the dry season is not very sensitive. （2） During the period under the pre-discharge dispatch, the runoff volume slightly increases as well as both the average water level and the highest water level rise in the usual year. While in the wet and dry years, the average increase in the runoff volume is 40.25×1 08 m3 and the average rises of the average water level and the highest water level are both 1.06 m. （3） As for the flood-storage dispatch, the flood volume increases slightly, in the dry and wet years, the flood volume, the average water level and the highest water level averagely reduce by 444.02×108 m3, 2.64 m and 1.42 m respectively. （4） Under the water-storage dispatch, the runoff volume slightly in- creases and the water level heightens in a sort in the usual year. And in the dry and wet years the average decreases in the runoff volume, the average water leve/and the highest water levels are respectively 185.27×108 m3, 3.13 m and 2.14 m. （5） During the period under the water-supplement dispatch, the runoff volume, the average water level and the highest water levels averagely decline by 337.7×108 m3, 1.89 m and 2.39 m respectively in the usual and wet years. However, in the dry year, the runoff volume increases as well as the average and highest water levels slightly go up. 展开更多
关键词 Three Gorges Reservoir dispatch mode Dongting Lake area water regime change Three Gorges Reservoir dispatch mode Dongting Lake area water regime change
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Three-photon-excited fluorescence of Tb3+-doped CaO-Al_2O_3-SiO_2 glass by femtosecond laser irradiation 认领 引用 被引量：3
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作者 马红萍 祝邦文 邹凤楼 《Journal of Rare Earths》 SCIE EI CAS 2008年第6期928-931,共4页
A near infrared to visible blue, green, and red upconversion luminescence in a Tb^3＋-doped CaO-Al2O3-SiO2 glass was studied, which was excited using 800 nm femtosecond laser irradiation. The upconversion luminescence... A near infrared to visible blue, green, and red upconversion luminescence in a Tb^3＋-doped CaO-Al2O3-SiO2 glass was studied, which was excited using 800 nm femtosecond laser irradiation. The upconversion luminescence was attributed to ^5D3→^7F5, ^5D3→^7F4, ^5D3→^7F3, ^5D4→^7F6, ^5D4→^7F5, ^5D4→^7F4, and ^5D4→^7F3 transitions of Tb^3＋. The relationship between upconversion luminescence intensity and the pump power indicated that a three-photon simultaneous absorption process was dominant in this upconversion luminescence. The intense red, green, and blue upconversion luminescence of Tb^3＋-doped CaO-Al2O3-SiO2 glass may be potentially useful in developing three-dimensional display applications. 展开更多
关键词 three-photon-excited fluorescence three-dimensional （3D） volumetric display Tb^3＋-doped CaO-Al2O3-SiO2 glass rare earths
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Prenatal Diagnosis of Sirenomelia by Two-Dimensional and Three-Dimensional Skeletal Imaging Ultrasound 认领 引用 被引量：3
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作者 刘蓉 陈欣林 +1 位作者 杨小红 马慧静 《Journal of Huazhong University of Science and Technology(Medical Sciences)》 2015年第6期928-931,共4页
Summary： This study sought to evaluate the contribution of two-dimensional ultrasound （2D-US） and three-dimensional skeletal imaging ultrasound （3D-SUIS） in the prenatal diagnosis of sirenomelia. Be- tween Septem... Summary： This study sought to evaluate the contribution of two-dimensional ultrasound （2D-US） and three-dimensional skeletal imaging ultrasound （3D-SUIS） in the prenatal diagnosis of sirenomelia. Be- tween September 2010 and April 2014, a prospective study was conducted in a single referral center using 3D-SU1S performed after 2D-US in 10 cases of sirenomelia. Diagnostic accuracy and detailed findings were compared with postnatal three-dimensional helical computed tomography （3D-HCT）, radiological findings and autopsy. Pregnancy was terminated in all 10 sirenomelia cases, including 9 singletons and I conjoined twin pregnancy, for a total of 5 males and 5 females. These cases of sirenomelia were deter- mined by autopsy and/or chromosomal examination. Initial 2D-US showed that there were 10 cases of oligohydranmios, bilateral renal agenesis, bladder agenesis, single umbilical artery, fusion of the lower limbs and spinal abnormalities; 8 cases of dipus or monopus; 2 cases of apus; and 8 cases of cardiac abnormalities. Subsequent 3D-SUIS showed that there were 9 cases of scoliosis, l0 cases of sacrococ- cygeal vertebra dysplasia, 3 cases of hemivertebra, 1 case of vertebral fusion, 3 cases of spina bifida, and 5 cases of rib abnormalities. 3D-SUIS identified significantly more skeletal abnormalities than did 2D-US, and its accuracy was 79.5% （70/88） compared with 3D-HCT and radiography. 3D-SUIS seems to be a useful complementary method to 2D-US and may improve the accuracy of identifying prenatal skeletal abnormalities related to sirenomelia. 展开更多
关键词 sirenomelia three-dimensional skeletal imaging ultrasound three-dimensional helicalcomputed tomography
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THREE-DIMENSIONAL MATHEMATICAL MODEL AND ITS APPLICATION IN THE NEIGHBORHOOD OF THE THREE GORGES RESERVOIR DAM IN THE YANGTZE RIVER 认领 引用 被引量：2
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作者 方红卫 Wolfgang Rodi 《Acta Mechanica Sinica》 SCIE EI CAS 2002年第3期235-243,共9页
The calculation of flow and sediment transport is one of the most important tasks in river engineering. The task is particularly difficult because a number of complex physical phenomena should be accounted for more re... The calculation of flow and sediment transport is one of the most important tasks in river engineering. The task is particularly difficult because a number of complex physical phenomena should be accounted for more realistically in a model with a predictive power. Three-dimensional calculations of river flow and suspended sediment transport are performed in this paper with application in the Three Gorges Reservoir in the Yangtze River. A period of 76 years after the dam is built is simulated and the results are compared with laboratory measurements obtained by Tsinghua University whereby the model is verified and calibrated. Generally speaking, the calculated results agree well with the experiments, demonstrating that the present model can be used for flow and sediment transport prediction in rivers. 展开更多
关键词 three-dimensional mathematical model sediment transport Three Gorges Project (TGP)
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THREE-SPHERE INEQUALITIES FOR SECOND ORDER SINGULAR PARTIAL DIFFERENTIAL EQUATIONS 认领 引用
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作者 张松艳 《Acta Mathematica Scientia》 SCIE 2010年第3期993-1003,共11页
In this article, we give the three-sphere inequalities and three-ball inequalities for the singular elliptic equation div（A∨u） - Vu =0, and the three-ball inequalities on the characteristic plane and the three-cyli... In this article, we give the three-sphere inequalities and three-ball inequalities for the singular elliptic equation div（A∨u） - Vu =0, and the three-ball inequalities on the characteristic plane and the three-cylinder inequalities for the singular parabolic equation Эtu-div（A∨u） ＋ Vu = 0, where the singular potential V belonging to the Kato-Fefferman- Phong＇s class. Some applications are also discussed. 展开更多
关键词 Three-sphere inequality three-cylinder inequality singular partial differential equation Kato-Fefferman-Phong＇s class Lipschitz domain
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Spatiotemporal changes in vegetation coverage and its driving factors in the Three-River Headwaters Region during 2000-2011 认领 引用 被引量：61
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作者 LIU Xianfeng ZHANG Jinshui +4 位作者 ZHU Xiufang PAN Yaozhong LIU Yanxu ZHANG Donghai LIN Zhihui 《Journal of Geographical Sciences》 SCIE CSCD 2014年第2期288-302,共15页
The Three-River Headwaters Region （TRHR）, which is the source area of the Yangtze River, Yellow River, and Lancang River, is of key importance to the ecological secu- rity of China. Because of climate changes and hu... The Three-River Headwaters Region （TRHR）, which is the source area of the Yangtze River, Yellow River, and Lancang River, is of key importance to the ecological secu- rity of China. Because of climate changes and human activities, ecological degradation oc- curred in this region. Therefore, ＂The nature reserve of Three-River Sou,＇ce Regions＂ was established, and ＂The project of ecological protection and construction for the Three-River Headwaters Nature Reserve＂ was implemented by the Chinese government. This study, based on MODIS-NDVI and climate data, aims to analyze the spatiotemporal changes in vegetation coverage and its driving factors in the TRHR between 2000 and 2011, from three dimensions. Linear regression, Hurst index analysis, and partial correlation analysis were employed. The results showed the following： （1） In the past 12 years （2000-2011）, the NDVI of the study area increased, with a linear tendency being 1.2%/10a, of which the Yangtze and Yellow River source regions presented an increasing trend, while the Lancang River source region showed a decreasing trend. （2） Vegetation coverage presented an obvious spatial difference in the TRHR, and the NDVI frequency was featured by a bimodal structure. （3） The area with improved vegetation coverage was larger than the degraded area, being 64.06% and 35.94%, respectively during the study period, and presented an increasing trend in the north and a decreasing trend in the south. （4） The reverse characteristics of vegetation cov- erage change are significant. In the future, degradation trends will be mainly found in the Yangtze River Basin and to the north of the Yellow River, while areas with improving trends are mainly distributed in the Lancang River Basin. （5） The response of vegetation coverage to precipitation and potential evapotranspiration has a time lag, while there is no such lag in the case of temperature. （6） The increased vegetation coverage is mainly attributed to the warm-wet climate change and the implementation of the ecological protection project. 展开更多
关键词 vegetation coverage spatiotemporal change future trend influence factors Three-River HeadwatersRegion
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Preliminary report on methane emissions from the Three Gorges Reservoir in the summer drainage period 认领 引用 被引量：15
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作者 Fei Lu Le Yang +10 位作者 Xiaoke Wang Xiaonan Duan Yujing Mu Wenzhi Song Feixiang Zheng Junfeng Niu Lei Tong Hua Zheng Yongjuan Zhou Jiangxiao Qiu Zhiyun Ouyang 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2011年第12期2029-2033,共5页
Recently reported summertime methane （CH4） emissions （6.7 ± 13.3 mg CH4/（m2·hr）） from newly created marshes in the drawdown area of the Three Gorges Reservoir （TGR）, China have triggered broad concer... Recently reported summertime methane （CH4） emissions （6.7 ± 13.3 mg CH4/（m2·hr）） from newly created marshes in the drawdown area of the Three Gorges Reservoir （TGR）, China have triggered broad concern in academic circles and among the public. The CH4 emissions from TGR water surfaces and drawdown areas were monitored from 3rd June to 16th October 2010 with floating and static chambers and gas chromatography. The average CH4 emission flux from permanently flooded areas in Zigui, Wushan and Yunyang Counties was （0.33 ± 0.09） mg CH4/（m2·hr）. In half of these hottest months of the year, the wilderness, cropland and deforested drawdown sites were aerobic and located above water level, and the CH4 emissions were very small, ranging from a sink at 0.12 mg CH4/（m2·hr） to a source at 0.08 mg CH4/（m2·hr） except for one mud-covered site after flood. Mean CH4 emission in flooded drawdown sites was 0.34 mg CH4/（m2·hr）. The emissions from the rice paddy sites in the drawdown area were averaged at （4.86 ± 2.31） mg CH4/（m2·hr）. Excepting the rice-paddy sites, these results show much lower emission levels than previously reported. Our results indicated considerable spatial and temporal variation in CH4 emissions from the TGR. Human activities and occasional events, such as flood, may also affect emission levels. Long-term CH4 measurements and modeling in a large region are necessary to accurately estimate greenhouse gas emissions from the TGR. 展开更多
关键词 methane the Three Gorges Reservoir drawdown area summer drainage uncertainty flood
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Probiotic Bio-Three induces Th1 and anti-inflammatory effects in PBMC and dendritic cells 认领 引用 被引量：26
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作者 Man-Chin Hua Tzou-Yien Lin +3 位作者 Chien-Chang Chen Ming-Wei Lai Man-Shan Kong Hung-Ju Chang 《World Journal of Gastroenterology》 SCIE CAS 2010年第28期3529-3540,共12页
AIM:To investigate the immune response of peripheral blood mononuclear cells(PBMCs)and dendritic cells (DCs)that were stimulated by probiotic preparations. METHODS:PBMCs were isolated,cultured,and stimulated with Bio-... AIM:To investigate the immune response of peripheral blood mononuclear cells(PBMCs)and dendritic cells (DCs)that were stimulated by probiotic preparations. METHODS:PBMCs were isolated,cultured,and stimulated with Bio-Three(a mixture of Bacillus mesentericus, Clostridium butyricum and Enterococcus faecalis;105, 10 6 and 10 7 CFU/mL for 24 h).Cytokine production of (1)circulating PBMCs;(2)PBMCs stimulated by probiotic preparation;(3)monocyte-derived DCs;and(4)DC andT cell co-culture was determined by enzyme-linked immunosorbent assay.Phenotypic analysis of circulating PBMCs was also investigated by flow cytometry.Blood was obtained from individuals who consumed Bio-Three (10 9 CFU/d B.mesentericus,C.butyricum and E.faecalis) for 2 wk,or those who did not take probiotics orally. RESULTS:In culture supernatants,interferon-γ(IFN-γ) and interleukin(IL)-10 production increased,but IL-4 and tumor necrosis factor-α(TNF-α)production by PBMCs decreased after 1 and 2 wk of probiotic treatment.Flow cytometry was also performed on day 14 and detected enhanced expression of CD11b,HLA-DR, CD4,CD45RA,CD25,CD44 and CD69 in response to Bio-Three.Furthermore,IL-10 and IL-12 were upregulated in supernatants of monocyte-derived DCs,and IFN-γand IL-10 were enhanced in supernatants of CD4 + T cells co-cultured with DCs. CONCLUSION:Bio-Three appeared to stimulate the Th1 immune response,downregulate pro-inflammatory cytokines(TNF-α)and upregulate anti-inflammatory cytokine(IL-10).Probiotics could be effective in activation of PBMCs and DCs. 展开更多
关键词 Probiotics Bio-Three Peripheral blood mono- nuclear cells Dendritic cells
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Real-time in situ three-dimensional integral videography and surgical navigation using augmented reality: a pilot study 认领 引用 被引量：11
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作者 Hideyuki Suenaga Huy Hoang Tran +5 位作者 Hongen Liao Ken Masamune Takeyoshi Dohi Kazuto Hoshi Yoshiyuki Mori Tsuyoshi Takato 《International Journal of Oral Science》 SCIE CAS CSCD 2013年第2期98-102,共5页
To evaluate the feasibility and accuracy of a three-dimensional augmented reality system incorporating integral videography for imaging oral and maxillofacial regions, based on preoperative computed tomography data. T... To evaluate the feasibility and accuracy of a three-dimensional augmented reality system incorporating integral videography for imaging oral and maxillofacial regions, based on preoperative computed tomography data. Three-dimensional surface models of the jawbones, based on the computed tomography data, were used to create the integral videography images of a subject＇s maxillofacial area. The three-dimensional augmented reality system （integral videography display, computed tomography, a position tracker and a computer） was used to generate a three-dimensional overlay that was projected on the surgical site via a half-silvered mirror. Thereafter, a feasibility study was performed on a volunteer. The accuracy of this system was verified on a solid model while simulating bone resection. Positional registration was attained by identifying and tracking the patient/surgical instrument＇s position. Thus, integral videography images of jawbones, teeth and the surgical tool were superimposed in the correct position. Stereoscopic images viewed from various angles were accurately displayed. Change in the viewing angle did not negatively affect the surgeon＇s ability to simultaneously observe the three-dimensional images and the patient, without special glasses. The difference in three-dimensional position of each measuring point on the solid model and augmented reality navigation was almost negligible （〈1 mm）; this indicates that the system was highly accurate. This augmented reality system was highly accurate and effective for surgical navigation and for overlaying a three-dimensional computed tomography image on a patient＇s surgical area, enabling the surgeon to understand the positional relationship between the preoperative image and the actual surgical site, with the naked eye. 展开更多
关键词 augmented reality computed tomography integral videography three-dimensional image
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Effects of an ecological conservation and restoration project in the Three-River Source Region, China 认领 引用 被引量：60
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作者 SHAO Quanqin CAO Wei +2 位作者 FAN Jiangwen HUANG Lin XU Xinliang 《Journal of Geographical Sciences》 SCIE CSCD 2017年第2期183-204,共22页
The first-stage of an ecological conservation and restoration project in the Three-River Source Region（TRSR）, China, has been in progress for eight years. However, because the ecological effects of this project rema... The first-stage of an ecological conservation and restoration project in the Three-River Source Region（TRSR）, China, has been in progress for eight years. However, because the ecological effects of this project remain unknown, decision making for future project implementation is hindered. Thus, in this study, we developed an index system to evaluate the effects of the ecological restoration project, by integrating field observations, remote sensing, and process-based models. Effects were assessed using trend analyses of ecosystem structures and services. Results showed positive trends in the TRSR since the beginning of the project, but not yet a return to the optima of the 1970 s. Specifically, while continued degradation in grassland has been initially contained, results are still far from the desired objective, ‘grassland coverage increasing by an average of 20%–40%＇. In contrast, wetlands and water bodies have generally been restored, while the water conservation and water supply capacity of watersheds have increased. Indeed, the volume of water conservation achieved in the project meets the objective of a 1.32 billion m^3 increase. The effects of ecological restoration inside project regions was more significant than outside, and, in addition to climate change projects, we concluded that the implementation of ecological conservation and restoration projects has substantially contributed to vegetation restoration. Nevertheless, the degradation of grasslands has not been fundamentally reversed, and to date the project has not prevented increasing soil erosion. In sum, the effects and challenges of this first-stage project highlight the necessity of continuous and long-term ecosystem conservation efforts in this region. 展开更多
关键词 Three-River Source Region ecological conservation and restoration ecosystem monitoring and assessment ecological effects
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Impact of the Three Gorges Dam on reproduction of four major Chinese carps species in the middle reaches of the Changjiang River 认领 引用 被引量：30
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作者 黎明政 段中华 +2 位作者 高欣 曹文宣 刘焕章 《Chinese Journal of Oceanology and Limnology》 CSCD 2016年第5期885-893,共9页
Silver carp(Hypophthalmichthys molitrix),bighead carp(Aristichthys nobilis),grass carp(Ctenopharyngodon idella),and black carp(Mylopharyngodon piceus) are the four major Chinese carps and are commercially important aq... Silver carp(Hypophthalmichthys molitrix),bighead carp(Aristichthys nobilis),grass carp(Ctenopharyngodon idella),and black carp(Mylopharyngodon piceus) are the four major Chinese carps and are commercially important aquaculture species in China.Reproduction of these carp has declined since the construction of the Three Gorges Dam(TGD) due to an altered water flow and thermal regime in the Changjiang(Yangtze) River.However,details of the changes in reproduction of the four species are not well understood.To assess the impact of the TGD on reproduction of the four carp,we investigated their eggs and larvae at Yidu City,which is 80 km below the TGD,during 2005-2012.We examined differences in larval abundance of the four species in the Jianli section(350 km downstream of the TGD) before(1997-2002)and after(2003-2012) construction of the TGD.Based on these observations,the first spawning date of the four species was delayed a mean of about 25 days after the dam was constructed.Mean egg abundance in the Yidu section of the river was 249 million and mean larval abundance was 464 million,which were significant decreases since the 1980 s.Moreover,larval abundance in the Jianli section after the dam was constructed was significantly lower than that before construction(ANCOVA,P<0.05).The observed larval abundance accounted for only 24.66%of the predicted value in 2003 when the dam was first inundated.The present spawning grounds between the TGD and Yidu section of the river are very similar to those described in the 1980 s,and some spawning grounds exist upstream of the TGD.Large free-flowing stretches upstream of the TGD and the creation of artificially flooded downstream reaches are needed to stimulate spawning and effectively conserve these four major Chinese carps species. 展开更多
关键词 Changjiang(Yangtze) River Three Gorges Dam Chinese carp reproduction eggs and larvae
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Spatial patterns of ecosystem vulnerability changes during 2001–2011 in the three-river source region of the Qinghai-Tibetan Plateau, China 认领 引用 被引量：22
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作者 GUO Bing ZHOU Yi +8 位作者 ZHU Jinfeng LIU Wenliang WANG Futao WANG Litao YAN Fuli WANG Feng YANG Guang LUO Wei JIANG Lin 《Journal of Arid Land》 SCIE CSCD 2016年第1期23-35,共13页
The three-river source region (TRSR, including Yangtze, Yellow and Lancang rivers), located in the Qinghai-Tibetan Plateau, China, is a typical alpine zone with apparent ecosystem vulnerability and sensitivity. In thi... The three-river source region (TRSR, including Yangtze, Yellow and Lancang rivers), located in the Qinghai-Tibetan Plateau, China, is a typical alpine zone with apparent ecosystem vulnerability and sensitivity. In this paper, we introduced many interdisciplinary factors, such as landscape pattern indices (Shannon diversity index and Shannon evenness index) and extreme climate factors (number of extreme high temperature days, number of extreme low temperature days, and number of extreme precipitation days), to establish a new model for evaluating the spatial patterns of ecosystem vulnerability changes in the TRSR. The change intensity (CI) of ecosystem vulnerability was also analyzed. The results showed that the established evaluation model was effective and the ecosystem vulnerability in the whole study area was intensive. During the study period of 2001–2011, there was a slight degradation in the eco-environmental quality. The Yellow River source region had the best eco-environmental quality, while the Yangtze River source region had the worst one. In addition, the zones dominated by deserts were the most severely deteriorated areas and the eco-environmental quality of the zones occupied by evergreen coniferous forests showed a better change. Furthermore, the larger the change rates of the climate factors (accumulative temperature of ≥10°C and annual average precipitation) are, the more intensive the CI of ecosystem vulnerability is. This study would provide a scientific basis for the eco-environmental protection and restoration in the TRSR. 展开更多
关键词 eco-environmental vulnerability climate factors spatial patterns three-river source region
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Climate change and its driving effect on the runoff in the "Three-River Headwaters" region 认领 引用 被引量：19
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作者 ZHANG Shifeng HUA Dong +1 位作者 MENG Xiujing ZHANG Yongyong 《Journal of Geographical Sciences》 SCIE CSCD 2011年第6期963-978,共16页
Based on the precipitation and temperature data of the 12 meteorological stations in the ＂Three-River Headwaters＂ region and the observed runoff data of Zhimenda in the headwater sub-region of the Yangtze River, Tan... Based on the precipitation and temperature data of the 12 meteorological stations in the ＂Three-River Headwaters＂ region and the observed runoff data of Zhimenda in the headwater sub-region of the Yangtze River, Tangnaihai in the headwater sub-region of the Yellow River and Changdu in the headwater sub-region of the Lancang River during the period 1965-2004, this paper analyses the trends of precipitation, temperature, runoff depth and carries out significance tests by means of Mann-KendalI-Sneyers sequential trend test. Mak- kink model is applied to calculate the potential evaporation. The runoff model driven by pre- cipitation and potential evaporation is developed and the influence on runoff by climate change is simulated under different scenarios. Results show that during the period 1965-2004 the temperature of the ＂Three-River Headwaters＂ region is increasing, the runoff of the three hydrological stations is decreasing and both of them had abrupt changes in 1994, while no significant trend changes happen to the precipitation. The runoff model suggests that the precipitation has a positive effect on the runoff depth, while the potential evaporation plays a negative role. The influence of the potential evaporation on the runoff depth of the Lancang River is found to be the significant in the three rivers; and that of the Yellow River is the least. The result of the scenarios analysis indicates that although the precipitation and the potential evaporation have positive and negative effects on runoff relatively, fluctuated characteristics of individual effect on the runoff depth in specific situations are represented. 展开更多
关键词 the ＂Three-River Headwaters＂ region climate change Makkink model driving model scenariosanalysis
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Diversity of microbial plankton across the Three Gorges Dam of the Yangtze River,China 认领 引用 被引量：8
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作者 Shang Wang Raymond M. Dong +8 位作者 Christina Z. Dong Liuqin Huang Hongchen Jiang Yuli Wei Liang Feng Deng Liu Guifang Yang Chuanlun Zhang Hailiang Dong 《Geoscience Frontiers》 SCIE CAS 2012年第3期335-349,共15页
The Three Gorges Dam （TGD） of the Yangtze River, China, is one of the largest irrigation and hydroelectric engineering projects in the world. The effects of huge man-made projects like TGD on fauna and macrophyte ar... The Three Gorges Dam （TGD） of the Yangtze River, China, is one of the largest irrigation and hydroelectric engineering projects in the world. The effects of huge man-made projects like TGD on fauna and macrophyte are obvious, mainly through changes of water dynamics and flow pattern; however, it is less clear how microorganisms respond to such changes. This research was aimed to examine differences in microbial diversity at different seasons and locations （in front of and behind the TGD）. In addition, differences between particle-attached and free-living communities were also examined. The community structures of total and potentially active microorganisms in the water columns behind and in front of the TGD were analyzed with the DNA- and RNA-based 16S rRNA gene phylogenetic approaches over three different seasons. Clone libraries of 16S rRNA genes were prepared after ampli- fication from extracted DNA and, for some samples, after preparing cDNA from extracted rRNA. Differ- ences were observed between sites at different seasons and between free-living and particle-attached communities. Both bacterial and archaeal communities were more diverse in summer than in winter, due to higher nutrient levels and warmer temperature in summer than in winter. Particle-attached micro- organisms were more diverse than free-living communities, possibly because of higher nutrient levels and heterogeneous geochemical micro-environments in particles. Spatial variations in bacterial community structure were observed, i.e., the water reservoir behind the TGD （upstream） hosted more diverse bacte- rial populations than in front of the dam （downstream）, because of diverse sources of sediments and waters from upstream to the reservoir. These results have important implications for our understanding of responses of microbial communities to environmental changes in river ecosystems affected by dam construction. 展开更多
关键词 Archaea Bacteria Free-living Particle-attached Three Gorges Dam
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Impact of the Three Gorges Dam on the spawning stock and natural reproduction of Chinese sturgeon in the Changjiang River,China 认领 引用 被引量：16
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作者 高欣 林鹏程 +2 位作者 黎明政 段中华 刘焕章 《Chinese Journal of Oceanology and Limnology》 CSCD 2016年第5期894-901,共8页
Chinese sturgeon(Acipenser sinensis) is the flagship species of the Changjiang River.The migration route of this species is blocked by the first dam,the Gezhou Dam,and its reproduction is affected by the Three Gorges ... Chinese sturgeon(Acipenser sinensis) is the flagship species of the Changjiang River.The migration route of this species is blocked by the first dam,the Gezhou Dam,and its reproduction is affected by the Three Gorges Dam(TGD),one of the largest dams in the world.We studied the impact of the impoundment of the Three Gorges Reservoir(TGR) since 2003 on the spawning stock and the natural reproduction of the Chinese sturgeon by using our monitoring data from 1997 to 2013.Results indicate that TGR impoundment has delayed the first spawning dates of the fish from middle-late October to late November,decreased the amount of spawning activities from twice to only once each year,and significantly reduced egg production.In particular,the fish did not demonstrate any spawning activities in 2013.Therefore,TGR impoundment significantly affects the natural reproduction of the fish downstream of the TGD.The spawning stock size of the fish is also predicted to further decrease in the future,which will lead to a risk of population extinction.Ecological regulations must be imposed on decreasing the water temperature to 20℃before mid-October and increasing water discharge downstream of the TGD in October to induce spawning of the Chinese sturgeon. 展开更多
关键词 Chinese sturgeon Three Gorges Dam spawning activity spawning stock conservation
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The hydrological effect between Jingjiang River and Dongting Lake during the initial period of Three Gorges Project operation 认领 引用 被引量：37
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作者 CHANG Jiang LI Jingbao +4 位作者 LU Dianqing ZHU Xiang LU Chengzhi ZHOU Yueyun DENG Chuxiong 《Journal of Geographical Sciences》 SCIE 2010年第5期771-786,共16页
Based on the measured hydrological data from 1951 to 2008, the chain hydrological effect between Jingjiang River and Dongting Lake is analyzed by comparative method after the Three Gorges Project operation. The result... Based on the measured hydrological data from 1951 to 2008, the chain hydrological effect between Jingjiang River and Dongting Lake is analyzed by comparative method after the Three Gorges Project operation. The result indicates that 1） the scouring amount in Jing- jiang River made up 78.9% of the total from Yichang to Chenglingji, and its average scouring intensity was higher than the latter; 2） the water and sand diversion rates at the three outlets of the Jingjiang River were reduced by 2.33% and 2.78% separately; 3） the proportion of multi-year average runoff and sediment through the three outlets in the total into the Dongting Lake decreased by 7.7% and 24.4% respectively; 4） in Dongting Lake, the speed of sediment accumulation was lowered by 26.7%, in flood season, the runoff amount was 20.2% less than the multi-year average value, leading to seasonal scarcity of water year by year. The former prolonged the lake life, while the latter induced droughts in summer and fall in successive years, shortage of drinking and industrial water, shipping insecurity, as well as ecological problems such as decrease of birds and quick increase of Microtus fortis; 5） The multi-year average values of sediment and flood transporting capacity at the lake outlet were respec- tively increased by 26.6% and 3.7%, the adapt to the new change of the river-lake embankments were protected effectively. Then, to relation, some suggestions were put forward, such as optimizing further operation program of the Three Gorges Reservoir, reexamining the idea of river and lake regulation, and maintaining connection of the river and the lake. 展开更多
关键词 initial period of Three Gorges Project operation silt-discharge relating hydrological effect DongtingLake area
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Use of three-dimensional printing in preoperative planning in orthopaedic trauma surgery: A systematic review and meta-analysis 认领 引用 被引量：12
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作者 Catrin Morgan Chetan Khatri +2 位作者 Sammy A Hanna Hutan Ashrafian Khaled M Sarraf 《World Journal of Orthopedics》 2020年第1期57-67,共11页
BACKGROUND With the increasing complexity of surgical interventions performed in orthopaedic trauma surgery and the improving technologies used in threedimensional(3D)printing,there has been an increased interest in t... BACKGROUND With the increasing complexity of surgical interventions performed in orthopaedic trauma surgery and the improving technologies used in threedimensional(3D)printing,there has been an increased interest in the concept.It has been shown that 3D models allow surgeons to better visualise anatomy,aid in planning and performing complex surgery.It is however not clear how best to utilise the technique and whether this results in better outcomes.AIM To evaluate the effect of 3D printing used in pre-operative planning in orthopaedic trauma surgery on clinical outcomes.METHODS We performed a comprehensive systematic review of the literature and a metaanalysis.Medline,Ovid and Embase were searched from inception to February 8,2018.Randomised controlled trials,case-control studies,cohort studies and case series of five patients or more were included across any area of orthopaedic trauma.The primary outcomes were operation time,intra-operative blood loss and fluoroscopy used.RESULTS Seventeen studies(922 patients)met our inclusion criteria and were reviewed.The use of 3D printing across all specialties in orthopaedic trauma surgery demonstrated an overall reduction in operation time of 19.85%[95%confidence intervals(CI):(-22.99,-16.71)],intra-operative blood loss of 25.73%[95%CI:(-31.07,-20.40)],and number of times fluoroscopy was used by 23.80%[95%CI:(-38.49,-9.10)].CONCLUSION Our results suggest that the use of 3D printing in pre-operative planning in orthopaedic trauma reduces operative time,intraoperative blood loss and the number of times fluoroscopy is used. 展开更多
关键词 Orthopaedic surgery Trauma Three-dimensional printing
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Plankton community composition in the Three Gorges Reservoir Region revealed by PCR-DGGE and its relationships with environmental factors 认领 引用 被引量：30
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作者 YAN Qingyun YU Yuhe +2 位作者 FENG Weisong YU Zhigang CHEN Hongtao 《Journal of Environmental Sciences》 SCIE EI CAS 2008年第6期732-738,共7页
To explore the relationships between community composition and the environment in a reservoir ecosystem, plankton communities from the Three Gorges Reservoir Region were studied by PCR-denaturing gradient gel electrop... To explore the relationships between community composition and the environment in a reservoir ecosystem, plankton communities from the Three Gorges Reservoir Region were studied by PCR-denaturing gradient gel electrophoresis fingerprinting. Bacterial and eukaryotic operational taxonomic units （OTUs）, generated by DGGE analysis of the PCR-amplified 16S and 18S rRNA genes, were used as surrogates for the dominant ＂biodiversity units＂. OTU composition among the sites was heterogeneous; 46.7% of the total bacterial OTUs （45） and 64.1% of the eukaryotic OTUs （39） were identified in less than half of the sampling sites. Unweighted pair group method with arithmetic averages （UPGMA） clustering of the OTUs suggested that the plankton communities in the Xiangxi Rive sites were not always significantly different from those from the Yangtze River sites, despite clear differences in their environmental characterizations. Canonical correspondence analysis （CCA） was applied to further investigate the relationships between OTU composition and the environmental factors. The first two CCA ordination axes suggested that the bacterial community composition was primarily correlated with the variables of NO3^--N, dissolved oxygen （DO）, and SiO3^2--Si, whereas, the eukaryotic community was mainly correlated with the concentrations of DO, PO4^3--P, and SiO3^2--Si. 展开更多
关键词 plankton community environmental factors denaturing gradient gel electrophoresis （DGGE） spatial pattern Three Gorges Reservoir Region
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The Three-Dimensional Collagen Scaffold Improves the Sternness of Rat Bone Marrow Mesenchymal Stem Cells 认领 引用 被引量：7
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作者 Sufang Han Yannan Zhao +4 位作者 Zhifeng Xiao Jin Han Bing Chen Lei Chen Jianwu Dai 《Journal of Genetics and Genomics》 SCIE CAS CSCD 2012年第12期633-641,共9页
Mesenchymal stem cells （MSCs） show the great promise for the treatment of a variety of diseases because of their self-renewal and multipotential abilities. MSCs are generally cultured on two-dimensional （2D） subst... Mesenchymal stem cells （MSCs） show the great promise for the treatment of a variety of diseases because of their self-renewal and multipotential abilities. MSCs are generally cultured on two-dimensional （2D） substrate in vitro. There are indications that they may simultaneously lose their sternness and multipotentiality as the result of prolonged 2D culture. In this study, we used three-dimensional （3D） collagen scaffolds as rat MSCs cartier and compared the properties of MSCs on 3D collagen scaffolds with monolayer cultured MSCs. The results demonstrated that collagen scaffolds were suitable for rat MSCs adherence and proliferation. More importantly, compared to MSCs under 2D culture, 3D MSCs significantly maintained higher expression levels of stemness genes （Oct4, Sox2, Rex-1 and Nanog）, yielded high frequencies of colony-forming units-fibroblastic （CFU-F） and showed enhanced osteogenic and adipogenic differentiation efficiency upon induction. Thus, 3D collagen scaffolds may be beneficial for expanding rat MSCs while maintaining the stem cell properties in vitro. 展开更多
关键词 Three-dimensional culture Mesenchymal stem ceils Collagen scaffold Stemness
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