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Crop production changes and the impact of Grain for Green program in the Loess Plateau of China

Journal of Arid Land 2020年第1期12卷 18-28页

作者： LYU Changhe xu zhiyuan Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China Institute of Rural Development Zhejiang Academy of Agricultural SciencesHangzhou 310021China

Since the Grain for Green(GFG)program was implemented in 1999,most steeply sloping farmlands in the Loess Plateau of China have been returned to forestland and *** understand its impact on the food production,this study analyzed the spatiotemporal changes of food crop production(FCP)in the plateau and quantified the contribution of sown area and yield changes to the total FCP during 1998–2014 using factor decomposition models,and then discussed the impact of GFG program on the FCP based on literature *** the implementation of GFG program,total sown area in the Loess Plateau quickly deceased by 17.3%from 1998 to 2003,and then gradually restored to 1.03×107 hm2 in ***,it slightly decreased to 1.02×107 hm2(94.6%of the area in 1998)in *** contrast,total FCP generally showed an apparent growth trend,averagely increased by 1.71%per year in the whole plateau during 1998–*** increase was jointly contributed by the improved yield of individual crops,and the adjustment of cropping structure,i.e.,the expansion of high yield maize *** factor decomposition analysis results indicate that the sown area shrinkage only reduced the growth rate of total FCP by 0.29%per year during 1998–2014,although a significant impact was found for the early stage of 1999–*** results suggest that the implementation of GFG program would not induce an obvious risk of the food ***,it is suggested that the GFG program should be set as a long-term strategic policy,by not only supporting the conversion of slope farmlands,but also helping local farmers to seek sustainable ways of land use to improve the income and *** can be combined with the poverty eradication program,to simultaneously achieve the national goals of ecological civilization building and the livelihood improvement of rural people in the Loess *** rainfall limitation,the conversion of slope farmlands should be prioritized to grasslands.

关键词： spatiotemporal change farmland conversion hilly region factor decomposition semi-arid regions

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A new pinching theorem for complete self-shrinkers and its generalization

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Science China Mathematics 2020年第6期63卷 1139-1152页

作者： Li Lei Hongwei xu zhiyuan xu Center of Mathem atical Sciences Zhejiang UniversityHangzhou 310027China Departm ent of Mathem atics Hangzhou Normal UniversityHangzhou 310036China

In this paper,we firstly verify that if Mn is an n-dimensional complete self-shrinker with polynomial volume growth in Rn+1,and if the squared norm of the second fundamental form of M satisfies 0≤S-1≤1/18,then S≡1 and M is a round sphere or a *** generally,let M be a complete λ-hypersurface of codimension one with polynomial volume growth in Rn+1 with λ≠*** we prove that there exists a positive constant γ,such that if |λ|≤γ and the squared norm of the second fundamental form of M satisfies0≤S-βλ≤1/18,then S≡βλ,λ> 0 and M is a *** βλ=1/2(2+λ2+|λ|(λ2+4)1/2).

关键词： rigidity theorem the second fundamental form self-shrinker λ-hypersurface

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On the generalized Chern conjecture for hypersurfaces with constant mean curvature in a sphere

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Science China Mathematics 2021年第7期64卷 1493-1504页

作者： Li Lei Hongwei xu zhiyuan xu Center of Mathematical Sciences Zhejiang UniversityHangzhou 310027China Department of Mathematics Hangzhou Normal UniversityHangzhou 310036China

Let M be a compact hypersurface with constant mean curvature in Denote by H and S the mean curvature and the squared norm of the second fundamental form of M,*** verify that there exists a positive constantγ(n)depending only on n such that if|H|≤γ(n)andβ(n,H)≤S≤β(n,H)+n/18,then S≡β(n,H)and M is a Clifford ***,β(n,H)=n+n^(3)/2(n-1)H^(2)+n(n-2)/2(n-1)(1/2)n^(2)H^(4)+4(n-1)H^(2).

关键词： generalized Chern conjecture hypersurfaces with constant mean curvature rigidity theorem scalar curvature the second fundamental form

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Switched-capacitor Multi-level Inverter with Equal Distribution of the Capacitors Discharging Phases

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Chinese Journal of Electrical Engineering 2020年第4期6卷 42-52页

作者： zhiyuan xu Xiaofeng Zheng Tong Lin Jia Yao Adrian Ioinovici College of Automation Nanjing University of Science and TechnologyNanjing 210014China College of Automation Nanjing University of Aeronautics and AstronauticsNanjing 210016China

A new switched-capacitor(2n+1)levels inverter with a single input source and equal charge of the capacitors at the input voltage V_(in) is *** with its peers from the same class of inverters,the proposed one features an equal or lower components count referred to the boost ***,it presents an additional advantage:each voltage level can be obtained by using different capacitors in the discharging phase,such that the decreasing part of the staircase output waveform can be synthesized with different switching topologies than those used in the increasing *** a consequence,all the capacitors are discharged at the same voltage value at the end of each half-cycle,allowing for the use of smaller capacitors of equal *** the capacitors are connected in parallel in the charging phase,there is no need to equalize their voltages,so no additional current spikes *** also implies less electromagnetic emission(EMI).Two types of modulation strategies are proposed.A half-height fundamental switching frequency modulation strategy allows for reaching the desired peak of the output voltage during the highest voltage level *** is advantageous in application of the inverter as a front end of a grid supplied by green sources of energy.A high frequency(f_(s)=200 kHz)modulation strategy accompanied by a duty-cycle control is advantageous for applications which require miniaturization.A 9-level switched-capacitor multi-level inverter(SCMLI)is analyzed and *** power losses are *** experimental results for a 9-level inverter with V_(in)=40 V,V_(out)=110 Vrms 50 Hz,200 W confirm the theoretical expectations.

关键词： Switched-capacitor multi-level inverter half-height frequency modulation

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Analysis and Optimization of a Five-phase Hybrid Excitation Flux Switching Machine Based on the Consistency and Complementarity Principle

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Chinese Journal of Electrical Engineering 2021年第3期7卷 52-64页

作者： Ming Cheng zhiyuan xu Minghao Tong Guishu Zhao Peng Han School of Electrical Engineering Southeast UniversityNanjing 210096China School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China School of Electrical and Automation Engineering Nanjing Normal UniversityNanjing 210023China Ansys Inc.San JoseCA 95134USA

In this study,the general optimal stator poles/rotor teeth(P/T)combination equation of the E-core hybrid excitation flux switching(HEFS)machines are introduced,and a new HEFS machine is proposed and ***,the influences of three different P/T combinations(10/18,10/19,and 10/21)on the HEFS machines are investigated with two-dimensional(2D)finite element analyses(2D-FEA).Meanwhile,the consistency and complementarity principle of the armature windings is analyzed in detail to give reasonable explanations to the simulated *** general optimal P/T combination equation of the E-core HEFS machines is deduced mathematically to provide an effective guidance on the selection of P/T *** optimal P/T combination calculated by the general equation agrees with the simulated results which confirm the correctness of the mathematical ***,the optimizations on the proposed HEFS machine are implemented to obtain higher output torque and better flux-regulation ratio characteristics based on which the cogging torque and torque ripple are reduced significantly.

关键词： Consistence and complementarity principle HEFS machines stator poles/rotor teeth combination

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Genetic basis of negative heterosis for growth traits in chickens revealed by genome-wide gene expression pattern analysis

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Journal of Animal Science and Biotechnology 2021年第4期12卷 1267-1280页

作者： Chunning Mai Chaoliang Wen zhiyuan xu Guiyun xu Sirui Chen Jiangxia Zheng Congjiao Sun Ning Yang National Engineering Laboratory for Animal Breeding and Key Laboratory of Animal Genetics Breeding and ReproductionMinistry of Agriculture and Rural AffairsChina Agricultural UniversityBeijing 100193China

Background:Heterosis is an important biological phenomenon that has been extensively utilized in agricultural ***,negative heterosis is also pervasively observed in nature,which can cause unfavorable impacts on production *** with systematic studies of positive heterosis,the phenomenon of negative heterosis has been largely ignored in genetic studies and breeding programs,and the genetic mechanism of this phenomenon has not been thoroughly elucidated to ***,we used chickens,the most common agricultural animals worldwide,to determine the genetic and molecular mechanisms of negative ***:We performed reciprocal crossing experiments with two distinct chicken lines and found that the body weight presented widely negative heterosis in the early growth of *** heterosis of carcass traits was more common than positive heterosis,especially breast muscle mass,which was over−40%in reciprocal ***-wide gene expression pattern analyses of breast muscle tissues revealed that nonadditivity,including dominance and overdominace,was the major gene inheritance *** genes,including a substantial number of genes encoding ATPase and NADH dehydrogenase,accounted for more than 68%of differentially expressed genes in reciprocal crosses(4257 of 5587 and 3617 of 5243,respectively).Moreover,nonadditive genes were significantly associated with the biological process of oxidative phosphorylation,which is the major metabolic pathway for energy release and animal growth and *** detection of ATP content and ATPase activity for purebred and crossbred progenies further confirmed that chickens with lower muscle yield had lower ATP concentrations but higher hydrolysis activity,which supported the important role of oxidative phosphorylation in negative heterosis for growth traits in ***:These findings revealed that nonadditive genes and their related oxidative phosphorylation were the m

关键词： Chicken Growth Gene expression patterns Heterosis Oxidative phosphorylation

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Microbial community structure of different tongue fur types in patients with chronic gastritis

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Journal of Traditional Chinese Medicine 2023年第2期43卷 365-373页

作者： WANG Yanan YUAN Li WANG Li xu zhiyuan RUAN Hua CHENG Xiangdong DONG Changwu College of Traditional Chinese Medicine Anhui University of Traditional Chinese MedicineHefeiAnhui 230000China Department of Surgery Cancer Hospital Affiliated to the University of Chinese Academy of SciencesHangzhou 310022China Department of Surgery Yuhang Hospital of Traditional Chinese MedicineHangzhou 310022China

OBJECTIVE:To explore the correlation between tongue and oral microbiota,we studied the microbial community structure of different tongue coating types in patients with chronic ***:16S rDNA gene sequencing and bioinformatics analysis were used to study the dynamic changes and correlation of microbial flora in patients with chronic gastritis,healthy people,and patients with different tongue *** addition,it was also discussed between the severity of gastritis and the microflora of tongue ***:The microbial diversity of tongue fur in patients with chronic gastritis was significantly different from healthy *** were significant changes in bacterial communities’diversity and relative abundance between extra tongue fur in patients but not in healthy *** bacteria with relative abundance>1%and P<0.05 among different tongue fur flora were dominant bacteria,including 12 phyla such as Bacteroidetes,Proteobacteria and Firmicutes,and 256 genera such as Neisseria,Prevotella_7 and ***:The changes in oral flora in patients with chronic gastritis were related to tongue ***,the significant microbiota might enlighten further study on the correlation between tongue inspection and oral microbiota in patients with chronic gastritis.

关键词： gastritis medicine Chinese traditional RNA,ribosomal,16S oral microflora tongue manifestation

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Cloning,purification,and characterization of branched-chain α-keto acid decarboxylases from Lactococcus lactis strains with different 3-methylbutanal production abilities

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Food Bioscience 2022年第3期47卷 947-953页

作者： Chen Chen Jiajie Yuan Haiyan Yu Xinman Lou Bei Wang zhiyuan xu Huaixiang Tian School of Perfume and Aroma Technology Shanghai Institute of TechnologyShanghai201418PR China School of Food and Health Beijing Technology and Business UniversityBeijing100048PR China State Key Laboratory of Dairy Biotechnology Shanghai Engineering Research Center of Dairy BiotechnologyDairy Research InstituteBright Dairy & Food Co.LtdShanghai200436PR China

Lactococcus lactis is an important food-grade microorganism that has been successfully applied as a starter to increase the level of 3-methylbutanal produced during the ripening of *** variants of branched-chain α-keto acid decarboxylase (KADC) were discovered in *** strains with different 3-methylbutanal production *** genes encoding KADCs of varying lengths (KADC-long,KADC-middle,and KADC-short) were cloned and heterologously expressed into Escherichia *** activity was only detected in the *** cloned with the KADC-long-encoding *** modeling of the three KADC recombination proteins showed that an active-site residue (Glu462) and an S-pocket structure were necessary for the ability to catalyze ***-long showed maximum activity at pH 7.0 and 30 ℃.The substrate hydrolysis and kinetic parameters demonstrated that KADC-long efficiently produces 2-methylbutanal and *** heterologous expression of the full-length kdcA in low-3-methylbutanal-yield *** strains increased their production *** results of this study demonstrate the function of the complete KADC in 3-methylbutanal production.

关键词： Lactococcus lactis Branched-chainα-keto acid decarboxylase 3-Methylbutanal Thiamin diphosphate(ThDP)-dependent enzyme family

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A solution-processed nanoscale COF-like material towards optoelectronic applications

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Science China Chemistry 2021年第1期64卷 82-91页

作者： Qiang Fu Ting Wang Yanna Sun Nan Zheng Zengqi Xie Di Lu zhiyuan xu Xiangjian Wan Yamin Zhang Yongsheng Liu The Centre of Nanoscale Science and Technology and Key Laboratory of Functional Polymer Materials Institute of Polymer ChemistryCollege of ChemistryNankai UniversityTianjin 300071China Institute of Polymer Optoelectronic Materials and Devices State Key Laboratory of Luminescent Materials and DevicesSouth China University of TechnologyGuangzhou 510640China State Key Laboratory of Applied Organic Chemistry College of Chemistry and Chemical EngineeringLanzhou UniversityLanzhou 730000China Renewable Energy Conversion and Storage Center Nankai UniversityTianjin 300071China

Two-dimensional(2 D)covalent organic frameworks(COFs)with periodic functionalπ-electron systems are an emerging class of optoelectronic ***,almost all conjugated COFs so far are insoluble and hard to process,which hampers severely their optoelectronic ***,a solution-processable,nanoscale and sp2 carbon-conjugated COF-like material,PDPP-C20 was successfully designed and *** solution-processed PDPP-C20 films exhibit high crystallinity and excellent charge transport properties along out-of-plane directions,combined with the highest occupied molecular orbital(HOMO)/lowest unoccupied molecular orbital(LUMO)levels of-5.36/-3.75 e V,making PDPP-C20 suitable for electronic device *** efficiency as high as 21.92%has been demonstrated when it was used as a functional interfacial layer in perovskite solar cells,coupled with dramatically improved stability in comparison with the control device due to the superior hydrophobicity of PDPP-C20 layer as well as its passivation effect on perovskite ***,the soluble PDPP-C20 could also be used as donor in bulk-heterojunction organic solar cells and an initial efficiency of 2.46%has been *** results indicate that this new class of soluble and nanoscale COF-like materials should offer a new arena of functional materials for optoelectronic devices.

关键词： solution-processable covalent organic frameworks perovskite solar cells mobility passivation

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Efficiently Writing Bragg Grating in High-Birefringence Elliptical Microfiber for Label-Free Immunosensing with Temperature Compensation

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Advanced Fiber Materials 2021年第5期3卷 321-330页

作者： Peng Xiao zhiyuan xu Deming Hu Lili Liang Lipeng Sun Jie Li Yang Ran Bai‑Ou Guan Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications Institute of Photonics TechnologyJinan UniversityGuangzhou 510632China Ji Hua Laboratory Foshan 528300China Institute of Information Technology Handan UniversityHandan 056005China

Immunosensor is a powerful tool in healthcare and clinic,food and drug industry,and environmental ***-free fiber-optic immunosensors have shown a myriad of advantages,such as high sensitivity,anti-electromagnetic interference,and afield measurement via the fiber ***,the fiber-optic based sensor may bear the temperature cross-talk,especially under the warming condition for bio-activating the immune *** this study,we proposed a highly birefringent microfiber Bragg grating for immunosensing with the *** birefringent microfiber was drawn from the elliptical cladding multimode fiber that was ablated by the CO2 *** considerably large energy overlap region offered by the original multimode fiber favored the efficient inscription of FBG with high *** dual reso-nances derived by the orthogonal polarization states presented similar temperature responsivities but significantly different ambient refractive index sensitivities,allowing the temperature-compensational RI *** human immunoglobulin G(IgG)molecules were anchored on the surface of the microfiber grating probe by the covalent functionalization technique to enable the specific detection of the anti-IgG *** proposed method promises a high-efficiency and low-cost design for the microfiber Bragg grating-based biosensor without being subjected to the temperature cross-sensitivity.

关键词： Fiber-optic biosensors Microfiber Fiber Bragg grating Birefringence Temperature compensation Immunosensing

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