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Interior gradient and Hessian estimates for the Dirichlet problem of semi-linear degenerate elliptic systems: A probabilistic approach

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Science China Mathematics 2019年第10期62卷 1851-1886页

作者： jun dai Shanjian Tang Bingjie Wu School of Mathematical Sciences Fudan University

In this paper, we give interior gradient and Hessian estimates for systems of semi-linear degenerate elliptic partial differential equations on bounded domains, using both tools of backward stochastic differential equ... 详细信息

关键词： semi-linear degenerate elliptic systems quasi-derivatives backward stochastic differential equations Dirichlet problems

Independent control of harmonic amplitudes and phases via a time-domain digital coding metasurface

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Light(Science & Applications) 2018年第1期7卷 201-210页

作者： jun Yan dai Jie Zhao Qiang Cheng Tie jun Cui State Key Laboratory of Millimeter Waves Southeast University210096 NanjingChina Synergetic Innovation Center of Wireless Communication Technology Southeast University210096 NanjingChina

Harmonic manipulations are important for applications such as wireless communications,radar detection and biological monitoring.A general approach to tailor the harmonics involves the use of additional amplifiers and phase shifters for the precise control of harmonic amplitudes and phases after the mixing process;however,this approach leads to issues of high cost and system *** composed of a periodic array of subwavelength resonators provide additional degrees of freedom to realize customized responses to incident light and highlight the possibility for nonlinear control by taking advantage of time-domain ***,we designed and experimentally characterized a reflective time-domain digital coding metasurface,with independent control of the harmonic amplitude and *** the reflection coefficient is dynamically modulated in a predefined way,a large conversion rate is observed from the carrier signal to the harmonic components,with magnitudes and phases that can be accurately and separately *** addition,by encoding the reflection phases of the meta-atoms,beam scanning for multiple harmonics can be implemented via different digital coding sequences,thus removing the need for intricate phase-shift *** work paves the way for efficient harmonic control for applications in communications,radar,and related areas.

关键词： harmonic harmonics surface

First Principles Study on FeAs Single Layers

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Chinese Journal of Chemical Physics 2009年第2期22卷 139-142页

作者： jun dai Zhen-yu Li Jin-long Yang Hefei National Laboratory for Physical Sciences at Microscale University of Science and Technology of China Hefei 230026 China

FeAs^- single layer is tested as a simple model for LaFeAsO and BaFe2As2 based on firstprinciples calculations using generalized gradient approximation （GGA） and GGA＋U. The calculated single-layer geometric and electronic structures are inconsistent with that of bulk materials. The bulk collinear antiferromagnetic ground state failed to be obtained in the FeAs^- single layer. The monotonous behavior of the Fe-As distance in z direction upon electron or hole doping is also in contrast with bulk materials. The results indicate that, in LaFeAsO and BaFe2As2, interactions between FeAs layer and other layers beyond simple charge doping are important, and a single FeAs layer may not represent a good model for Fe based superconducting materials.

关键词： Superconductivity FeAs layer Magnetism Density functional theory

Measurement invariance and latent mean differences of the Chinese version physical activity self-efficacy scale across gender and education levels

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Journal of Sport and Health Science 2019年第1期8卷 46-54页

作者： Han Chen jun dai Yong Gao Department of Kinesiology and Physical Education Valdosta State University School of Sport Leisure Recreation and Arts Shanghai University of Sport Department of Kinesiology Boise State University

Background: Self-efficacy has been identified as an important determinant of youth's behavior change including physical activity(PA) participation. However, the dimensionality check of a PA self-efficacy scale has rarely been conducted in China. The current study aims to examine(1) the unidimensionality of a shortened Chinese version of PA self-efficacy scale(S-PASESC);(2) the measurement invariance of S-PASESC across gender and levels of education;(3) the latent factor mean difference between gender and levels of education;(4) the direct effects of self-efficacy on PA by different gender and education levels; and(5) the comparisons of the direct effects of self-efficacy on PA across gender and education ***: The participants were 5 th through 11 th grade public school students recruited from 7 cities located in different geographic regions of China. The final data include a total of 3003 participants(49.7% boys) who have completed the ***: Confirmatory factor analysis(CFA) test supported the unidimensionality of S-PASESC. The S-PASESC is invariant across gender and 3 levels of education at both configural, full metric, and full scalar levels. Findings from latent mean comparisons showed that boys reported higher PA self-efficacy than girls. Students' perceived PA self-efficacy tend to decrease from elementary to high school. Finally, self-efficacy positively related to PA by groups of different gender and education levels and the relationship between self-efficacy and PA is stronger among middle school boys than ***: Findings suggest S-PASESC is a valid scale for measuring Chinese students' PA self-efficacy.

关键词： Chinese adolescents Education levels Factor analysis Gender Latent mean comparison Measurement invariance Physical activity self-efficacy scale

Two New neo-Clerodane Diterpenoids from Scutellaria barbata

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Journal of Integrative Plant Biology 2008年第6期50卷 699-702页

作者： Sheng-jun dai Li Shen Yan Ren School of Pharmaceutical Science Yantai University Yantai 264005 China

Two new neo-clerodane diterpenoids, 6,7-dibenzoyloxybarbatin C （1, named barbatin D） and 6-（2-acetoxy-3-methylbutanoloxy）-7-（2-carbonyl-3-methylbutanoyloxy） barbatin C （2, named barbatin E） were isolated from the whole plant of Scutellaria barbata D. Don. Their structures were elucidated by spectroscopic methods including extensive 1 D and 2D NMR analyses. In vitro, compounds 1-2 showed cytotoxic activities against three human cancer lines, namely, HONE-1 nasopharyngeal, KB oral epidermoid carcinoma, and HT29 colorectal carcinoma cells, and with IC50 values in the range of 3.5-6.7μM.

关键词： barbatin D barbatin E cytotoxic activity neo-clerodane diterpenoid Scutellaria barbata

Adsorption and desorption of Cu2＋ on paddy soil aggregates pretreated with different levels of phosphate

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Journal of Environmental Sciences 2017年第5期29卷 311-320页

作者： jun dai Wenqin Wang Wenchen Wu Jianbo Gao Changxun Dong College of Sciences Nanjing Agricultural University Nanjing 210095 China College of Resources and Environmental Sciences Nanjing Agricultural University Nanjing 210095 China South China Institute of Environmental Sciences Ministry of Environmental Protection Guangzhou 510655 China

Interactions between anions and cations are important for understanding the behaviors of chemical pollutants and their potential risks in the *** we prepared soil aggregates of a yellow paddy soil from the Taihu Lake region,and investigated the effects of phosphate（P） pretreatment on adsorption-desorption of Cu2＋ of soil aggregates,free iron oxyhydrates-removed soil aggregates,goethite,and kaolinite with batch adsorption *** results showed that Cu2＋ adsorption was reduced on the aggregates pretreated with low concentrations of P,and promoted with high concentrations of P,showing a V-shaped *** with the untreated aggregates,the adsorption capacity of Cu2＋ was reduced when P application rates were lower than 260,220,130 and110 mg/kg for coarse,clay,silt and fine sand fractions,*** the contrary,the adsorption capacity of Cu2＋ was higher on P-pretreated soil aggregates than on the control ones when P application rates were greater than those ***,the desorption of Cu2＋ was enhanced at low levels of P,but suppressed at high levels of P,displaying an inverted V-shaped change over P *** Cu2＋ adsorption by the aggregate particles with and without P pretreatments was well described by the Freundlich *** results were obtained on P-pretreated ***,such P effects on Cu2＋adsorption-desorption were not observed on kaolinite and free iron oxyhydrates-removed soil *** present results indicate that goethite is one of the main soil substances responsible for the P-induced promotion and inhibition of Cu2＋ adsorption.

关键词： Paddy soil Aggregates Copper (Ⅱ) Adsorption and desorption

Products and production routes for the catalytic conversion of seed oil into fuel and chemicals: a comprehensive review

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Science China Chemistry 2015年第7期58卷 1110-1121页

作者： Mazloom Shah Jian-jun dai Qing-Xiang Guo Yao Fu Anhui Province Key Laboratory of Biomass Clean Energy Department of Chemistry University of Science and Technology of China

With the depletion of fossil resources, there is a need to find alternative resources of fuels and chemicals. The use of renewable feedstock such as those from seed oil processing is one of the best available resources that have come to the fore-front recently. This paper critically analyzes and highlights major factors in the biodiesel industry, such as seeds oil composition, production methods, properties of biodiesel, problems and potential solutions of using vegetable seed oil, the composition, quality and effective utilization of crude glycerol, the catalytic conversion of glycerol into possible fuels and chemicals.

关键词： seed oil catalytic conversion biodiesel glycerol fuels and chemicals

Observed spatiotemporal variation of three-dimensional structure and heat/salt transport of anticyclonic mesoscale eddy in Northwest Pacific

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Journal of Oceanology and Limnology 2020年第6期38卷 1654-1675页

作者： dai jun WANG Huizan ZHANG Weimin AN Yuzhu ZHANG Ren College of Meteorology and Oceanography National University of Defense TechnologyChangsha 410073China P.O.Box 5111 Beijing 100094China

As in-situ observations are sparse,targeted observations of a specific mesoscale eddy are ***,it is difficult to study the three-dimensional structure of moving mesoscale *** April to September 2014,an anticyclonic eddy located at 135°E-155°E,26°N-42°N was observed using 17 rapidsampling Argo floats,and the spatiotemporal variations in the three-dimensional structure were *** results are as follows:(1)the eddy was identified and tracked using satellite altimeter *** had a lifetime of 269 days and an average radius of 91.5 *** lifetime of the eddy can be divided into three phases,i.e.,the initiation,maturity,and termination *** depth of its influence reached 1000 m;(2)the Argo profiles were divided into seven periods(approximately 20 days in each)for composite analysis,and the composite Argo profiles and CARS2009(CSIRO Atlas of Regional Seas)climatology data were merged following the data-interpolating variational analysis(DIVA)method to reconstruct the three-dimensional *** temperature and salinity anomaly cores of the anticyclonic mesoscale eddy are located from 400 to 600 *** 800 to 900 m,there is an area of low salinity at the center of the eddy.A high concentration anomaly of dissolved oxygen was located at approximately 250 m;(3)to better understand the features of the eddy and its interaction with the surroundings,we calculated the anomalous velocity of the geostrophic flow and the heat,salt,dissolved oxygen transport anomaly,and discussed the eddy's origin and its adjustments to *** maximum heat,salt,and oxygen transport caused by eddy were 9.37×10^11 W,3.08×10^3 kg/s,and 2.70×10^2 kg/s,which all occurred during the termination *** study highlights the applicability of using Argo floats to understand the three-dimensional structure thermohaline features of eddies in the North Pacific.

关键词： Argo three-dimensional structure spatiotemporal variation dissolved oxygen

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Expression of kallikrein-related peptidase 7 is decreased in prostate cancer

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Asian Journal of Andrology 2015年第1期17卷 106-110,I0010页

作者： Chong-Yu Zhang Yu Zhu Wen-Bin Rui jun dai Zhou-jun Shen Department of Urology Ruijin Hospital School of Medicine Shanghai Jiaotong University Shanghai China.

Recent evidence suggests that the human kallikrein 7 （KLK7） is differentially regulated in a variety of tumors. The aim of this study was to determine the expression of kallikrein-related peptidase 7 and KLK7 in our large collection of prostate samples. Between August 2000 and December 2012, 116 patients with histologically confirmed prostate cancer （PCa） and 92 with benign prostate hyperplasia （BPH） were recruited into the study. Using immunohistochemistry, quantitative reverse transcription polymerase chain reaction （RT-PCR） and western blot, kallikrein-related peptidase 7 expression in BPH and PCa tissues was determined at the mRNA and protein levels. The relationships between kallikrein-related peptidase 7 mRNA expression and clinicopathological features were analyzed. A total of 64 of 92 （69.57%） benign cases showed positive staining for KLK7 and 23 of 116 （19.83%） malignant cases showed positive, the difference of KLK7 expression between PCa and BPH was statistically significant （P〈 0.001）. The expression level of kallikrein-related peptidase 7 mRNA was significantly decreased in PCa tissues compared with that in BPH tissues and normal prostate tissue. Kallikrein-related peptidase 7 mRNA exhibited different expression patterns in terms of localization depending on pathological category of PCa. Similarly, our western immunoblot analyses demonstrated that the protein expression levels of KLK7 was lower in PCa than in BPH tissues and normal prostate tissue. Kallikrein-related peptidase 7 and KLK7 expression are down-regulated in PCa and lower expression of kallikrein-related peptidase 7 closely correlates with higher Gleason score and higher prostate-specific antigen level.

关键词： human kallikrein 7 kallikrein-related peptidase 7 prostate cancer prostate-specific antigen