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The Effect of Ultrasound Scanning on the State Anxiety among Expectant Mothers in Their First Trimester and Predictors of Anxiety 认领 引用
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作者 Navodya Weerasinghe Oshadee Kaushalya De Silva Senapathige Nilan Kalidasa Rodrigo 《Open Journal of Obstetrics and Gynecology》 2025年第1期167-189,共23页
Background: Undergoing ultrasound scanning (USS) during the first trimester of pregnancy is highly imperative for expecting mothers, as it supports the early detection of any malformations, identifying the fetal numbe... Background: Undergoing ultrasound scanning (USS) during the first trimester of pregnancy is highly imperative for expecting mothers, as it supports the early detection of any malformations, identifying the fetal number, fetal growth, fetal sex, and calculation of delivery. Previous studies have shown that undergoing such prenatal screening procedures could reduce the antenatal anxiety levels of expectant mothers. The present study aimed to explore the impact of first-trimester ultrasound scanning towards the antenatal anxiety and identify the predictors of antenatal anxiety among expectant mothers in the first trimester. Methods: A repeated measure design study was conducted in Maternity Clinics of University Hospital KDU, Ninewells Care Hospital and Navy General Hospital over 4 months with one hundred and fifteen (n = 115) expectant mothers. Participants completed a general information sheet first and State Trait Anxiety Inventory (STAI) (Spielberger et al., 1970) was administered before and after undergoing the USS. Results: Mean age of the participants was 28.84 ± 3.68. The Wilcoxon Signed Rank test showed that there is a significant reduction of participants’ antenatal anxiety levels following the USS z = −5.658, p Conclusions: Findings suggest that undergoing the first trimester USS significantly reduces the antenatal state anxiety and partner’s support is an important factor in reducing the antenatal anxiety experienced by expectant mothers in the first trimester. Future studies can focus on how USS can contribute to alleviating antenatal anxiety in second and third trimesters. 展开更多
关键词 Antenatal Anxiety State Anxiety First Trimester Ultrasound Pregnancy
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Probability mass first flush evaluation for combined sewer discharges 认领 引用 被引量：5
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作者 Inhyeok Park Hongmyeong Kim +1 位作者 Soo-Kwon Chae Sungryong Ha 《Journal of Environmental Sciences》 SCIE EI CAS 2010年第6期915-922,共8页
The Korea government has put in a lot of effort to construct sanitation facilities for controlling non-point source pollution. The first flush phenomenon is a prime example of such pollution. However, to date, several... The Korea government has put in a lot of effort to construct sanitation facilities for controlling non-point source pollution. The first flush phenomenon is a prime example of such pollution. However, to date, several serious problems have arisen in the operation and treatment effectiveness of these facilities due to unsuitable design flow volumes and pollution loads. It is difficult to assess the optimal flow volume and pollution mass when considering both monetary and temporal limitations. The objective of this article was to characterize the discharge of storm runoff pollution from urban catchments in Korea and to estimate the probability of mass first flush （MFFn） using the storm water management model and probability density functions. As a result of the review of gauged storms for the representative using probability density function with rainfall volumes during the last two years, all the gauged storms were found to be valid representative precipitation. Both the observed MFFn and probability MFFn in BE-1 denoted similarly large magnitudes of first flush with roughly 40% of the total pollution mass contained in the first 20% of the runoff. In the case of BE-2, however, there were significant difference between the observed MFFn and probability MFFn. 展开更多
关键词 first flush combined sewer overflows （CSOs） probability mass first flush storm water management model best management practices
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First flush of storm runoff pollution from an urban catchment in China 认领 引用 被引量：56
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作者 LI Li-qing YIN Cheng-qing +1 位作者 HE Qing-ci KONG Ling-li 《Journal of Environmental Sciences》 SCIE EI CAS 2007年第3期295-299,共5页
Storm runoff pollution process was investigated in an urban catchment with an area of 1.3 km^2 in Wuhan City of China. The results indicate that the pollutant concentration peaks preceded the flow peaks in all of 8 mo... Storm runoff pollution process was investigated in an urban catchment with an area of 1.3 km^2 in Wuhan City of China. The results indicate that the pollutant concentration peaks preceded the flow peaks in all of 8 monitored storm events. The intervals between pollution peak and flow peak were shorter in the rain events with higher intensity in the initial period than those with lower intensity. The fractions of pollution load transported by the first 30% of runoff volume （FF30） were 52.2%-72.1% for total suspended solids （TSS）, 53.0%-65.3% for chemical oxygen demand （COD）, 40.4%-50.6% for total nitrogen （TN）, and 45.8%-63.2% for total phosphorus （TP）, respectively. Runoff pollution was positively related to non-raining days before the rainfall. Intercepting the first 30% of runoff volume can remove 62.4% of TSS load, 59.4% of COD load, 46.8% of TN load, and 54.1% of TP load, respectively, according to all the storm events. It is suggested that controlling the first flush is a critical measure in reduction of urban stormwater pollution. 展开更多
关键词 first flush stormwater pollution urban area rainfall pattem runoff
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Role of cetuximab in first-line treatment of metastatic colorectal cancer 认领 引用 被引量：11
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作者 Miguel Jhonatan Sotelo Beatriz García-Paredes +2 位作者 Carlos Aguado Javier Sastre Eduardo Díaz-Rubio 《World Journal of Gastroenterology》 SCIE CAS 2014年第15期4208-4219,共12页
The treatment of metastatic colorectal cancer(mCRC)has evolved considerably in the last decade,currently allowing most mCRC patients to live more than two years.Monoclonal antibodies targeting the epidermal growth fac... The treatment of metastatic colorectal cancer(mCRC)has evolved considerably in the last decade,currently allowing most mCRC patients to live more than two years.Monoclonal antibodies targeting the epidermal growth factor receptor(EGFR)and vascular endothelial growth factor play an important role in the current treatment of these patients.However,only antibodies directed against EGFR have a predictive marker of response,which is the mutation status of v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog(KRAS).Cetuximab has been shown to be effective in patients with KRAS wild-type mCRC.The CRYSTAL study showed that adding cetuximab to FOLFIRI(regimen of irinotecan,infusional fluorouracil and leucovorin)significantly improved results in the first-line treatment of KRAS wildtype mCRC.However,results that evaluate the efficacy of cetuximab in combination with oxaliplatin-based chemotherapy in this setting are contradictory.On the other hand,recent advances in the management of colorectal liver metastases have improved survival in these patients.Adding cetuximab to standard chemotherapy increases the response rate in patients with wild-type KRAS and can thus increase the resectability rate of liver metastases in this group of patients.In this paper we review the different studies assessing the efficacy of cetuximab in the first-line treatment of mCRC. 展开更多
关键词 Cetuximab First-line Metastatic colorectal cancer Colorectal liver metastases Elderly patients
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Compensation trends of the angulation of first molars:retrospective study of 1403 malocclusion cases 认领 引用 被引量：24
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作者 Hong Su Bing Han +3 位作者 Sa Li Bin Na Wen Ma Tian-Min Xu 《International Journal of Oral Science》 SCIE CAS CSCD 2014年第3期175-181,共7页
We investigated the compensatory trends of mesiodistal angulation of first molars in malocclusion cases. We compared differences in the angulation of first molars in different developmental stages, malocclusion classi... We investigated the compensatory trends of mesiodistal angulation of first molars in malocclusion cases. We compared differences in the angulation of first molars in different developmental stages, malocclusion classifications and skeletal patterns. The medical records and lateral cephalogrammes of 1 403 malocclusion cases taken before treatment were measured to evaluate compensation of molar angulation in relation to the skeletal jaw. The cases were stratified by age, Angle classification and skeletal patterns. Differences in the mesiodistal angulation of the first molars were compared among the stratifications. We observed three main phenomena. First,angulation of the upper first molar varied significantly with age and tipped most distally in cases aged,12 years and least distally in cases aged.16 years. The lower first molar did not show such differences. Second, in Angle Class II or skeletal Class II cases, the upper first molar was the most distally tipped, the lower first molar was the most mesially tipped, and opposite angulation compensation was observed in Class III cases. Third, in high-angle cases, the upper and lower first molars were the most distally tipped, and opposite angulation compensation was observed in low-angle cases. These data suggest that the angulation of the molars compensated for various growth patterns and malocclusion types. Hence, awareness of molar angulation compensation would help to adjust occlusal relationships, control anchorage and increase the chances of long-term stability. 展开更多
关键词 Angle classification angulation compensation first molar growth stages malocclusion sagittal skeletal patterns verticalskeletal patterns
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First-principles theory on electronic structure and floatability of spodumene 认领 引用 被引量：13
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作者 Gui-Chun He Hua-Mei Xiang +2 位作者 Wei Jiang Qian Kang Jian-Hua Chen 《Rare Metals》 SCIE EI CAS CSCD 2014年第6期742-748,共7页
The band structure, density of states, Mulliken populations, and frontier orbital of spodumene crystal were calculated using the first-principles method based on the density functional theory（DFT） and further analyz... The band structure, density of states, Mulliken populations, and frontier orbital of spodumene crystal were calculated using the first-principles method based on the density functional theory（DFT） and further analyzed in detail. The calculation results reveal that the O in spodumene is the most active and easily links with H＋in the water, but the active Li is very low, so it is better to add activator to increase the concentrate grade and recovery rate of spodumene in the flotation process. Si–O bonds in spodumene crystal are mainly covalent, since the covalency of Al–O bonds is stronger than that of Li–O bonds,and minerals dissociate along the weakest Li–O bonds. In addition, the study of the frontier orbital indicates that both O and Si atoms have large contribution to the frontier orbital in the spodumene crystal. Oleate and dodecylamine are used as the collectors of spodumene. The results contribute to the understanding of crystal structures of spodumene, and can be used in guiding related practical applications. 展开更多
关键词 Spodumene Electronic structure Floatability First-principles method Frontier orbital
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One-time fertilization at first flowering improves lint yield and dry matter partitioning in late planted short-season cotton 认领 引用 被引量：9
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作者 LUO Hong-hai WANG Qiang +3 位作者 ZHANG Jie-kun WANG Lei-shan LI Ya-bing YANG Guo-zheng 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2020年第2期509-517,共9页
Cotton producers have substantially reduced their inputs(labor,nutrients,and management)mainly by adopting a shortseason cropping management that is characterized by late sowing,high density,and reduced fertilization ... Cotton producers have substantially reduced their inputs(labor,nutrients,and management)mainly by adopting a shortseason cropping management that is characterized by late sowing,high density,and reduced fertilization with one-time application at the first bloom stage without lint yield reduction.However,it has been hypothesized that one-time fertilization at an earlier growth stage could be a more effective and economic management practice.A two-year field experiment was conducted by applying five fertilizer one-time fertilization at 0(FT1),5(FT2),10(FT3),15(FT4),and 20(FT5)days after the first flower appeared in the field and one three-split fertilizer application taken as the conventional control(FT6),making six treatments altogether.Cotton growth period,biomass accumulation,yield,and its formation were quantified.The results showed that the one-time fertilization did not affect the cotton growth progress as compared to FT6,however,the total crop cycles for FT3–FT5 were 3 days shorter.FT1 produced the highest cotton lint yield(1396 kg ha–1),which was similar to the FT6 but higher than the other treatments,and could be attributed to more bolls per unit area and higher lint percentage.Cotton yield was positively correlated with cotton plant biomass accumulated.FT1 had both the highest average(VT)(193.7 kg ha–1 d–1)and the highest maximum(VM)(220.9 kg ha–1 d–1)rates during the fast biomass accumulation period.These results suggest that one-time fertilizer application at the first flower stage might be an adjustment that is more effective than at first bloom,and allowed for easier decision making for application date due to non counting of plants with flowers is needed. 展开更多
关键词 one-time fertilization first flower cotton biomass accumulation yield
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First-principles study on the effect of high In doping on the conductivity of ZnO 认领 引用 被引量：7
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作者 侯清玉 李继军 +3 位作者 迎春 赵春旺 赵二俊 张跃 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第7期430-434,共5页
Based on the density functional theory （DFT）, using first-principles plane-wave ultrasoft pseudopotential method, the models of the unit cell of pure ZnO and two highly In-doped supercells of Zn0.9375In0.0625O and Z... Based on the density functional theory （DFT）, using first-principles plane-wave ultrasoft pseudopotential method, the models of the unit cell of pure ZnO and two highly In-doped supercells of Zn0.9375In0.0625O and Zn0.875In0.125O are constructed, and the geometry optimizations of the three models are carried out. The total density of states （DOS） and the band structures （BS） are also calculated. The calculation results show that in the range of high doping concentration, when the doping concentration is hihger than a specific value, the conductivity decreases with the increase of the doping concentration of In in ZnO, which is in consistence with the change trend of the experimental results. 展开更多
关键词 wurtzite ZnO high In doping conductivity first principles
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Basal-plane stacking-fault energies of Mg alloys: A first-principles study of metallic alloying effects 认领 引用 被引量：13
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作者 Qing Dong Zhe Luo +6 位作者 Hong Zhu Leyun Wang Tao Ying Zhaohui Jin Dejiang Li Wenjiang Ding Xiaoqin Zeng 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2018年第10期1773-1780,共8页
Generalized stacking-fault energies （GSFEs） of basal-plane stacking faults 11 and 12 in Mg alloys have been studied based on first-principles calculations, where 43 alloying elements were considered. It is found tha... Generalized stacking-fault energies （GSFEs） of basal-plane stacking faults 11 and 12 in Mg alloys have been studied based on first-principles calculations, where 43 alloying elements were considered. It is found that the most contributing features of alloying elements to GSFEs are bulk modulus, equilibrium volume, binding energy, atomic radius and ionization energy. Both bulk modulus and ionization energy exhibit positive relationships with GSFEs, and the others show opposite relationships. Multiple regressions have been performed to offer a quantitative prediction for basal-plane GSFEs in Mg-X systems. GSFEs, alloying effects of elements and the prediction model established within this work may provide guidelines for new Mg alloys design with better ductility. 展开更多
关键词 First-principles calculations Magnesium alloys Stacking-fault energy Alloying effect
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The Response of First Flowering Dates to Abrupt Climate Change in Beijing 认领 引用 被引量：16
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作者 白洁 葛全胜 戴君虎 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2011年第3期564-572,共9页
Phenological data on the First Flowering Date(FFD) of woody plants in Beijing from 1963-2007 are analyzed.The correlation between each species’ yearly FFD and the mean monthly temperatures for every year over a 45-ye... Phenological data on the First Flowering Date(FFD) of woody plants in Beijing from 1963-2007 are analyzed.The correlation between each species’ yearly FFD and the mean monthly temperatures for every year over a 45-year period is used to identify the month in which temperature has the most effect on FFD. Through further analysis,the FFDs of 48 woody plant species are shown to have advanced an average of 5.4 days from 1990-2007 compared to 1963-1989.The results indicate that 70.8%of species flowered significantly earlier(7 days on average) during the period 1990-2007,while only one species(2.1%) flowered significantly later.Moreover,the responses of FFD to climate change are shown to be different in two climatic stages, defined by an abrupt climate change point.Thirty-three species which first flower in March and April are sensitive to temperature are examined.The correlation coefficients between FFD and temperature for 20 species during the latter period(1990-2007) are shown to be larger than during the former period(1963- 1989),with a difference of around -0.87 days per 1℃on average.The paper concludes that with the warming of climate,the linear trend of FFD variation,as well as its responsiveness to temperature,became more prominent during 1990-2007 than 1963-1989.The data analyzed in this study present a strong biological indicator of climate change in Beijing,and provide further confirmation of previous results from regional and local studies across the Northern Hemisphere.Phenophase variations indicate that the climate is changing rapidly. 展开更多
关键词 phenology climate change first flowering date（FFD） woody plants
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Ignition-proof mechanism of magnesium alloy added with rare earth La from first-principle study 认领 引用 被引量：8
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作者 张国英 罗志成 +1 位作者 张辉 褚冉 《Journal of Rare Earths》 SCIE EI CAS CSCD 2012年第6期573-578,共6页
The surface segregation of La and its effect on the oxygen adsorption on a Mg （0001） surface for a coverage 0=-0.25 monolayer were performed by using first-principles calculations. The calculated results showed that... The surface segregation of La and its effect on the oxygen adsorption on a Mg （0001） surface for a coverage 0=-0.25 monolayer were performed by using first-principles calculations. The calculated results showed that La atoms preferred occupying surface sites to the bulk sites, which suggested the La surface segregation. When oxygen atoms adsorbed on a pure or La alloyed Mg （0001） surface, certain amount of heat would release, and La alloying made the heat released less, which might increase the ignition point of Mg alloy. Both Mg and La had strong atomic affinity with oxygen, so the oxidation film of Mg-La alloys consisted of MgO, La2O3. The denser La2O3 turned oxide film into free and close structure, and prevented oxygen from passing through the oxidation film. The La-O covalent bonding could explain why La2O3 was compact, and resulted in good ignition-proof of Mg-La alloys. 展开更多
关键词 magnesium alloys first-principle calculations rare earths surface segregation ignition-proof
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The prevalence of vision impairment and refractive error in 3654 first year students at Tianjin Medical University 认领 引用 被引量：9
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作者 Xue-Ying Shi Yi-Feng Ke +3 位作者 Nan Jin Hong-Mei Zhang Rui-Hua Wei Xiao-Rong Li 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2018年第10期1698-1703,共6页
AIM：To determine the prevalence of vision impairment（VI）and refractive error in first year university students at the Tianjin Medical University.METHODS：This is a cross-sectional observational cohort study of VI a... AIM：To determine the prevalence of vision impairment（VI）and refractive error in first year university students at the Tianjin Medical University.METHODS：This is a cross-sectional observational cohort study of VI and refractive error among first year university students at the Tianjin Medical University.The first year university students were involved in this study and were given a detailed questionnaire including age,birth date,and spectacle wearing history.A standardized ophthalmologic examination including visual acuity（VA）,slit-lamp examination,non-cycloplegic auto-refraction,objective refraction,fundus photography,and examination of their spectacles were recorded.RESULTS：A total of 3654 participants were included in this study.Totally 3436（94.03%） individuals had VI in this population.Totally 150（4.10%） individuals had VI due to ocular disease,including amblyopia,congenital cataract,retinal atrophy or degeneration,strabismus,congenital nystagmus,refractive surgery orthokeratology.Totally 3286（89.93%） subjects had VI due to refractive error.Only 218（5.97%） students were emmetropia.Moreover,refractive error was the main cause for the VI（95.63%）.Totally 3242（92.52%） students were myopia and the prevalence of mild,moderate,and high myopia subgroup was 27.05%,44.35%,and 21.26% respectively.Totally 44（1.29%） subjects were hyperopic.The rates of uncorrected visual acuity（UCVA）,presenting visual acuity（PVA）and best corrected visual acuity（BCVA）which better than 20/20 in both eyes were 5.65%,22.32% and 82.13% respectively.The rates of correction,under correction and well correction in myopia subjects were 82.73%,84.39% and 15.61%,respectively. CONCLUSION：We present a high prevalence of refractive errors and high rates of under correction refractive error among first year university students.These results may help to promote vision protection work in young adults. 展开更多
关键词 vision impairment refractive error corrective status myopia first year university students
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数据分布型sort-first并行图形绘制系统的研究与实现 认领 引用 被引量：12
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作者 金哲凡 林海 石教英 《计算机研究与发展》 EI 北大核心 2004年第2期376-382,共7页
sort first体系结构常用来构建高性能并行图形绘制系统 基于immediate mode的数据集中型sort first系统 ,对网络带宽高度依赖 ,网络带宽和归属计算易成为系统瓶颈 提出了一个基于retain mode的数据分布型并行绘制系统 ,工作原理是将几... sort first体系结构常用来构建高性能并行图形绘制系统 基于immediate mode的数据集中型sort first系统 ,对网络带宽高度依赖 ,网络带宽和归属计算易成为系统瓶颈 提出了一个基于retain mode的数据分布型并行绘制系统 ,工作原理是将几何数据分布于绘制结点 ,并利用帧间相似性动态调整绘制结点上的数据分布以适应视角的改变 ,有效地降低了数据分布所需的传输开销 系统利用Cell结构来控制并行粒度 展开更多
关键词 sort-first 并行绘制 数据分布 粒度 帧间相似性
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First principles calculations of alloying element diffusion coefficients in Ni using the five-frequency model 认领 引用 被引量：9
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作者 吴琼 李树索 +1 位作者 马岳 宫声凯 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第10期585-591,共7页
The diffusion coefficients of several alloying elements（Al,Mo,Co,Ta,Ru,W,Cr,Re） in Ni are directly calculated using the five-frequency model and the first principles density functional theory.The correlation factors... The diffusion coefficients of several alloying elements（Al,Mo,Co,Ta,Ru,W,Cr,Re） in Ni are directly calculated using the five-frequency model and the first principles density functional theory.The correlation factors provided by the five-frequency model are explicitly calculated.The calculated diffusion coefficients show their excellent agreement with the available experimental data.Both the diffusion pre-factor（D 0） and the activation energy（Q） of impurity diffusion are obtained.The diffusion coefficients above 700 K are sorted in the following order：DAl〉DCr〉DCo〉DTa〉DMo〉DRu〉DW〉D Re.It is found that there is a positive correlation between the atomic radius of the solute and the jump energy of Ni that results in the rotation of the solute-vacancy pair（E 1）.The value of E 2-E 1（E 2 is the solute diffusion energy） and the correlation factor each also show a positive correlation.The larger atoms in the same series have lower diffusion activation energies and faster diffusion coefficients. 展开更多
关键词 first-principles theory diffusion coefficients alloying element superalloy activation energy and diffusion pre-factor
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Existence patterns of Dy in β-NiAl from first-principles calculations 认领 引用 被引量：4
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作者 Tian Zhang Hong-Bo Guo +1 位作者 Sheng-Kai Gong Hui-Bin Xu 《Rare Metals》 SCIE EI CAS CSCD 2016年第4期356-360,共5页
Intermetallic compound β-NiA1 is a promising material in high temperature applications due to its high melting temperature, high strength, low density, and good oxidation resistance. However, its application remains ... Intermetallic compound β-NiA1 is a promising material in high temperature applications due to its high melting temperature, high strength, low density, and good oxidation resistance. However, its application remains limited because of its relatively poor cyclic oxidation resistance. Addition of reactive element （RE） Dy can improve the cyclic oxidation of NiA1 alloys significantly. However, the mechanism of Dy addition is not clear. Even the existence pattern of Dy in NiA1 is unspecified. Therefore, in the present study, the impurity formation energies of Dy in stoichiometric NiA1, Ni-rich, and Al-rich NiA1 for the substitution cases were studied by first-principles density functional theory. The results show that Dy could hardly substitute for either Ni or A1 atoms in NiA1. However, calculations for dissolution energies show that Dy could be easily dissolved in AI vacancies in all three types of NiA1, which provides a new existence pattern of Dy in NiA1 beyond experimental detection. 展开更多
关键词 Existence pattern Dy A1 vacancies First-principles
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First-principles studies of electronic,optical,and mechanical properties of γ-Bi2Sn2O7 认领 引用 被引量：4
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作者 胡朝浩 殷学辉 +3 位作者 王殿辉 钟燕 周怀营 饶光辉 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第6期523-527,共5页
The detailed theoretical studies of electronic,optical,and mechanical properties of γ-Bi2Sn2O7 are carried out by using first-principle density functional theory calculations.Our calculated results indicate that γ-B... The detailed theoretical studies of electronic,optical,and mechanical properties of γ-Bi2Sn2O7 are carried out by using first-principle density functional theory calculations.Our calculated results indicate that γ-Bi2Sn2O7 is the p-type semiconductor with an indirect band gap of about 2.72 e V.The flat electronic bands close to the valence band maximum are mainly composed of Bi-6s and O-2p states and play a key role in determining the electrical properties of γ-Bi2Sn2O7.The calculated complex dielectric function and macroscopic optical constants including refractive index,extinction coefficient,absorption coefficients,reflectivity,and electron energy-loss function show that γ-Bi2Sn2O7 is an excellent light absorbing material.The analysis on mechanical properties shows that γ-Bi2Sn2O7 is mechanically stable and highly isotropic. 展开更多
关键词 γ-Bi2Sn2O7 electronic structure optical properties first-principle calculations
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Sedimentary Characteristics and Model of Gravity Flow Depositional System for the First Member of Upper Miocene Huangliu Formation in Dongfang Area, Yinggehai Basin, Northwestern South China Sea 认领 引用 被引量：15
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作者 Ming Sun Hua Wang +4 位作者 Jihua Liao Huajun Gan Jun Xiao Jinfeng Ren Shu'e Zhao 《Journal of Earth Science》 SCIE CAS CSCD 2014年第3期506-518,共13页
The gravity flow deposit were mainly developed in the lowstand systems tract（LST） of the first member of Upper Miocene Huangliu Formation（Ehl1） in Dongfang area, Yinggehai Basin, has become a valuable target for g... The gravity flow deposit were mainly developed in the lowstand systems tract（LST） of the first member of Upper Miocene Huangliu Formation（Ehl1） in Dongfang area, Yinggehai Basin, has become a valuable target for gas exploration and production. The gravity flow sedimentary characteristics of lithofacies associations, sedimentary texture, seismic facies and logging facies were described in detail on the basis of integrated analysis of cores, logging and seismic data. The sedimentary microfacies types composed of neritic sandbar, continental shelf mud, main channel, bifurcated or cross-cutting distributary channel, overspill, and natural levee are revealed under the constraint of high resolution sequence stratigraphic framework in the Ehl1. The gravity flow deposit system in the LST is divided into three evolution stages corresponding to periods of three parasequence sets. The gravity flow deposit was induced in the early LST, expanded rapidly in the middle LST and decreased slightly in the late LST. But its developing scale decreased sharply in the transgression systems tract（TST） and finally vanished in the highstand systems tract（HST）. This spatial evolution rule is constrained by the integrated function of sediments supply of the Vietnam Blue River in the LST, the development of local gradient change in sea floor（micro-topography, i.e., flexure slope break）, and the fall in relative sea level. On the basics of the deep study of the coupling relationship among the three main control factors, the sedimentary model is established as an optimal component of ＂source-channel-sink＂ for shallow marine turbidite submarine fan. 展开更多
关键词 Yinggehai Basin Dongfang area the first member of Upper Miocene Huangliu Formation（Ehl1） sedimentation characteristics gravity flow sedimentary model.
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Electronic structures of new tunnel barrier spinel MgAl_2O_4:first-principles calculations 认领 引用 被引量：7
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作者 Zhang, Delin Xu, Xiaoguang +5 位作者 Wang, Wei Zhang, Xin Yang, Hailing Wu, Yong Ma, Chuze Jiang, Yong 《Rare Metals》 SCIE EI CAS CSCD 2012年第2期112-116,共5页
The electronic structures of spinel MgAl 2 O 4 and MgOtunnel barrier materials were investigated using first-principles density functional theory calculations. Our results show that similar electronic structures are f... The electronic structures of spinel MgAl 2 O 4 and MgOtunnel barrier materials were investigated using first-principles density functional theory calculations. Our results show that similar electronic structures are found for the MgAl 2 O 4 and MgO tunneling barriers. The calculated direct energy gaps at the Γ-point are about 5.10 eV for MgAl 2 O 4 and 4.81 eV for MgO, respectively. Because of the similar feature in band structures from Γ high-symmetry point to F point ( band), the coherent tunneling effect might be expected to appear in MgAl 2 O 4-based MTJs like in MgO-based MTJs. The small difference of the surface free energies of Fe (2.9 J m 2 ) and MgAl 2 O 4 (2.27 J m 2 ) on the {100} orientation, and the smaller lattice mismatch between MgAl 2 O 4 and ferromagnetic electrodes than that between MgO and ferromagnetic electrodes, the spinel MgAl 2 O 4 can substitute MgO to fabricate the coherent tunneling and chemically stable magnetic tunnel junction structures, which will be applied in the next generation read heads or spintronic devices. 展开更多
关键词 tunnel barrier layer spinel MgAl 2 O 4 spintronic devices first-principles
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Effects of alloying elements X( X = Zr,V,Cr,Mn,Mo,W,Nb,Y) on ferrite/TiC heterogeneous nucleation interface: first-principles study 认领 引用 被引量：6
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作者 Hui-hui Xiong Heng-hua Zhang +1 位作者 Hui-ning Zhang Yang Zhou 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2017年第3期328-334,共7页
The segregation behavior of alloying elements X（ X = Zr,V,Cr,Mn,Mo,W,Nb,Y） on the ferrite（ 100） /TiC（ 100） interface has been investigated using first principles method,and the work of separation and interface e... The segregation behavior of alloying elements X（ X = Zr,V,Cr,Mn,Mo,W,Nb,Y） on the ferrite（ 100） /TiC（ 100） interface has been investigated using first principles method,and the work of separation and interface energy of ferrite / TiC interfaces alloyed by these elements were also analyzed. The results indicated that all these alloying additives except Y were thermodynamically favorable because of the negative segregation energy,showing that they have the tendency to segregate to the ferrite / TiC interface. When the Fe atom in the ferrite /TiC interface is replaced by Y,Zr,or Nb,the adhesive strength of the interface will be weakened due to the lower separation work,larger interfacial energy,and weaker electron effects. However,the introduction of Cr,Mo,W,Mn and V will improve the stability of the ferrite / TiC interface through strong interaction between these elements and C,and Cr-doped interface is the most stable structure. Therefore,the Cr,Mo,W,Mn and V in ferrite side of the interface can effectively promote ferrite heterogeneous nucleation on TiC surface to form fine ferrite grain. 展开更多
关键词 Fe/TiC interface Alloying element Heterogeneous nucleation Segregation First-principles
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Consensus problems of first-order dynamic multi-agent systems with multiple time delays 认领 引用 被引量：11
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作者 纪良浩 廖晓峰 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第4期50-55,共6页
Consensus problems of first-order multi-agent systems with multiple time delays are investigated in this paper. We discuss three cases： 1） continuous, 2） discrete, and 3） a continuous system with a proportional pl... Consensus problems of first-order multi-agent systems with multiple time delays are investigated in this paper. We discuss three cases： 1） continuous, 2） discrete, and 3） a continuous system with a proportional plus derivative controller. In each case, the system contains simultaneous communication and input time delays. Supposing a dynamic multi-agent system with directed topology that contains a globally reachable node, the sufficient convergence condition of the system is discussed with respect to each of the three cases based on the generalized Nyquist criterion and the frequency-domain analysis approach, yielding conclusions that are either less conservative than or agree with previously published results. We know that the convergence condition of the system depends mainly on each agent’s input time delay and the adjacent weights but is independent of the communication delay between agents, whether the system is continuous or discrete. Finally, simulation examples are given to verify the theoretical analysis. 展开更多
关键词 multi-agent time delays consensus first-order convergence
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