检索结果-南通市图书馆

Copper pollution decreases the resistance of soil microbial community to subsequent dry–rewetting disturbance

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2016年第1期28卷 155-164页

作者： Jing li Jun-Tao Wang Hang-Wei Hu yi-Bing Ma li-Mei Zhang Ji-Zheng He State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Faculty of Veterinary and Agricultural Sciences The University of Melbourne National Soil Fertility and Fertilizer Effects Long-term Monitoring Network Institute of Agricultural Resources and Regional PlanningChinese Academy of Agricultural Sciences

Dry–rewetting（DW） disturbance frequently occurs in soils due to rainfall and irrigation, and the frequency of DW cycles might exert significant influences on soil microbial communities and their mediated functions. However, how microorganisms respond to DW alternations in soils with a history of heavy metal pollution remains largely ***, soil laboratory microcosms were constructed to explore the impacts of ten DW cycles on the soil microbial communities in two contrasting soils（fluvo-aquic soil and red soil）under three copper concentrations（zero, medium and high）. Results showed that the fluctuations of substrate induced respiration（SIR） decreased with repeated cycles of DW alternation. Furthermore, the resistance values of substrate induced respiration（RS-SIR）were highest in non-copper-stressed（zero） soils. Structural equation model（SEM） analysis ascertained that the shifts of bacterial communities determined the changes of RS-SIR in both soils. The rate of bacterial community variance was significantly lower in noncopper-stressed soil compared to the other two copper-stressed（medium and high） soils,which might lead to the higher RS-SIR in the fluvo-aquic soil. As for the red soil, the substantial increase of the dominant group WPS-2 after DW disturbance might result in the low RS-SIR in the high copper-stressed soil. Moreover, in both soils, the bacterial diversity was highest in non-copper-stressed soils. Our results revealed that initial copper stress could decrease the resistance of soil microbial community structure and function to subsequent DW disturbance.

关键词： Copper stress Dry–rewetting disturbance Bacterial community Substrate induced respiration Resistance

Investigating the Nucleation Effect of DMDBS on Syndiotactic Polypropylene from the Perspective of Chain Conformation

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2020年第12期38卷 1355-1364页

作者： Xin-Xin Wang Jian-Jun yi li Wang Yuan Yuan Jia Chun Feng State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular ScienceFudan UniversityShanghai 200433China Laboratory for Synthetic Resin Research Petrochina Petrochemical Research Institute Beijing 102200China

The mechanism of nucleating agents(NAs)accelerating the crystallization of semi-crystlline polymers has received continuous attention due to the extreme importance in academic research and industry *** this work,the nucleation effect and probable mechanism of 1,3.2,4 bis(3,4-dimethylbenzylidene)sorbitol(DMDBS)on promoting the crystallization of syndiotactic polypropylene(sPP)was systematically *** results showed that DMDBS could significantly accelerate the crystallization process and did not change the crystalline form of *** in situ infrred spectra recorded in the crystallization process showed that in pristine sPP the tttt conformers decreased and the tgg conformers increased *** sPP/DMDBS system,DMDBS could promote the increase of tgg conformers rather than the decrease of tttt *** further analysis by 2D-IR spectra revealed that ttgg conformers increased prior to the decrease of tttt conformers in the sPP/DMDBS system comparing with pristine *** that ttgg conformers were basic elements of helical conformation of Form I crystal for sPP,we proposed a probable nucleation mechanism of DMDBS for sPP:DMDBS could stabilize the ttgg conformers which induced these ttgg conformers to pre-orientate and aggregate into helical conformation sequences as initial nuclei quickly and early to promote the sPP *** work provides some new insights into the nucleation mechanism of NAs for sPP.

关键词： Syndiotactic polypropylene Nucleating agent Crsallization Conformation

The valuation of multi-counterparties CDS with credit rating migration

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics(A Journal of Chinese Universities) 2020年第4期35卷 379-391页

作者： li Wen-yi GUO Hua-ying liANG Jin Anis Ben Brahim School of Mathematical Sciences Tongji UniversityShanghai 200092China Bank of China Consumer Finance Company limited Shanghai 200002China ENSTA Paris Tech Palaiseau Cedex 91762France

In this paper,the pricing of a Credit Default Swap(CDS)contract with multiple counterparties is *** pricing model takes into account the credit rating migration risk of the *** is a new model established under the reduced form framework,where the intensity rates are assumed to have structural *** derive from it a non-linear partial differential equation system where both positive and negative correlations of counterparties and the references are considered via a single factor ***,an ADI(Alternating Direction Implicit)difference method is used to solve the partial differential equations by *** the numerical results,the comparison of multi-counterparty CDS contract and the standard one are analyzed ***,the impact of default parameters on value of the contracts are discussed.

关键词： CDS credit rating migration risk multi-counterparties reduced form structure style

Preparation of Ultrafine Water-soluble Polymers Nanofiber Mats via Electrospinning

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2010年第2期26卷 318-322页

作者： SUN Guo-en TENG Hong ZHANG Chun-ling DOU Yan-li li yi Key Laboratory of Automobile Materials of Ministry of Education College of Materials Science and Engineering Jilin University Changchun 130025 P. R. China Department of Obstetrics and Gynecology The Second Hospital of Jilin University Changchun 130041 P. R. China

A series of water-soluble polymers such as poly（ethylene oxide）（PEO）, polyacrylamide（PAM） and poly（vinyl pyrrilidone）（PVP） was successfully prepared via the electrospinning of their aqueous solutions without the use of a surfactant. The effects of solution properties on the electrospinning of PEO, PAM and PVP solutions were investigated. The viscosity of the solution, charge density carried by the jet, and the surface tension of the solution are the key factors that influence the morphology and diameter size of the fibers. The viscosity of the solution was measured on a modular compact rheometer. The morphology and the diameter size distribution of the fibers were observed under an environmental scanning electron microscope（ESEM）. The results show that the diameters of the nanofibers electro spun from the solutions of these water soluble polymers were uniform and less than 300 nm.

关键词： Fiber Electrospinning Water-soluble polymer

Phase-mediated controllable intramolecular and intermolecular photocycloadditions assisted by supramolecular templates

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2022年第6期65卷 1129-1133页

作者： yi-Shou Wang li-ying Sun Yao-Yu Wang ying-Feng Han Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education Xi’an Key Laboratory of Functional Supramolecular Structure and MaterialsCollege of Chemistry and Materials ScienceNorthwest UniversityXi’an710127China

Understanding and controlling supramolecular template effect assembly via a photochemical reaction in different solid and solution phases is one of the main topics in photochemistry. Here, an interesting case of phase-mediated controllable intramolecular/intermolecular photochemical [2+2] cycloadditions assisted by supramolecular templates was demonstrated. Direct irradiation of the complexes in solution yields intramolecular photoproducts exclusively, whereas exposure of the solid powder sample under the same conditions yields intermolecular dinuclear species quantitatively. The nature of the phase and supramolecular interaction affects the geometrical arrangements of the metallacycles, leading to different cycloaddition products under photoirradiation. The crystal structures of different products were investigated by single-crystal X-ray diffraction, nuclear magnetic resonance(NMR) spectrometry, and electrospray ionization mass spectrometry(ESI-MS).

关键词： N-heterocyclic carbene photochemical cycloaddition template synthesis topochemistry stacking interactions

同方期刊数据库

Synthesis, Antimicrobial Activity, and Molecular Docking of Benzoic Hydrazide or Amide Derivatives Containing a 1,2,3-Triazole Group as Potential SDH Inhibitors

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2021年第5期39卷 1319-1330页

作者： Yue Ding ling Zhang Song Yang Zhong li Pei-yi Wang State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering Key Laboratory of Green Pesticide and Agricultural BioengineeringMinistry of EducationCenter for R&D of Fine Chemicals of Guizhou UniversityGuiyongGuizhou 550025China College of Pharmacy East China University of Science&TechnologyShanghai 200237China

The present study was carried out in an attempt to synthesize a new class of antimicrobial agents containing a 1,2,3-triazole motif formed by classical copper catalyzed click *** bioassay results showed that five compounds 5a;5e,5h,5j,and 5k possessed a remarkable growth inhibitory activity against Botryosphaeria dothidea,Rhizoctonia solani and Gibberella zeae with EC_(50) values within 10.0-0.306μg/*** in vitro efficacy was better than those of the commercial agrochemicals Azoxystrobin,Boscalid,and *** vivo trials showed that compound 51 was effective for the control of rice sheath blight and wheat scab with the effects of 75% and 95%,*** mechanism studies suggested that target compounds were potential succinate dehydrogenase inhibitors(SDHIs),which were proposed by the agreeable molecular docking study and restrained SDH activity(IC_(50)=3.95 μg/mL,51).Interestingly,compounds 5r and 5s displayed good antibacterial activity against *** vivo screening of 5r and 5s against rice bacterial blight afforded a superior control effect(up to 51%)than those of commercial agents Bismerthiazol and Thiodiazole *** current studies could support some title compounds to be the lead compounds for exploring highly bioactive antimicrobial substrates,particularly the potential SDHIs.

关键词： Hydrazide Amide 1,2,3-Triazole Molecular docking SDH inhibitory activity

Complex Spectra Structure of an Attosecond Pulse Train Driven by Sub-5-fs Laser Pulses

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2011年第7期28卷 137-139页

作者： YUN Chen-Xia TENG Hao ZHANG Wei WANG li-Feng ZHAN Min-Jie HE Xin-Kui WANG Bing-Bing WEI zhi-yi Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190

We present the observation of the additional spectral components between the odd order harmonics in the harmonic spectrum generated from argon gas driven by sub-5-fs laser *** theoretical analysis shows that the asymmetric laser field in both spatial and temporal domains leads to this complicated spectrum structure of high order harmonics.

关键词： laser harmonics spectrum

Enhanced electrochemical property of FePO_4-coated liNi_(0.5)Mn_(1.5)O_4 as cathode materials for li-ion battery

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science Bulletin 2017年第14期62卷 1004-1010页

作者： Ting-Feng yi Yan-Mei li Xiao-Ya li Jing-Jing Pan Qianyu Zhang Yan-Rong Zhu School of Chemistry and Chemical Engineering Anhui University of Technology Key Laboratory of Metallurgical Emission Reduction & Resources Recycling Ministry of Education Anhui University of Technology School of Environment and Civil Engineering Dongguan University of Technology

Pristine liNi0.5Mnl.5O4 and FePO4-coated one with Fd-3m space groups were prepared by a sol-gel method. The structure and performance were studied by X-ray diffraction （XRD） rietveld refinement, scanning electron microscopy （SEM）, high resolution transmission electron microscopy （HRTEM）, energy dispersive spectrometer （EDS） mapping, electrochemical impedance spectroscopy （EIS） and charge- discharge tests, respectively. The lattice parameters of all samples almost remain the same from the Rietveld refinement, revealing that the crystallographic structure has no obvious difference between pris- tine liNi0.5Mn1.5O4 and FePO4-coated one. All materials show similar morphologies with uniform particle distribution with small particle size, and FePO4 coating does not affect the morphology of liNi0.5Mnl05O 4 material. EDS mapping and HRTEM show that FePO4 may be successfully wrapped around the surfaces of ***.s04 particles, and provides an effective coating layer between the electrolyte and the surface of liNi0.5Mn1.5O4 particles. FePO4 （1 wt%）-coated ***.504 cathode shows the highest discharge capac- ity at high rate （2 C） among all samples. After 80 cycles, the reversible discharge capacity of FePO4 （1 wt%） coated liNi0.5Mn0.5O4 is 117 mAh g^-1, but the pristine one only has 50 mAh g^-1. FeP04 coating is an effec- tive and controllable way to stabilize the liNi0.5Mn1.5O4/electrolyte interface, and avoids the direct con- tact between liNi0.5Mn1.5O4 powders and electrolyte, then suppresses the side reactions and enhances the electrochemical performance of the liNi0.5Mn1.5O4.

关键词： liNi0.5Mn1.5O4 FePO4 coating Electrochemical property lithium-ion batteries

Structural Evolution of Ultra-High Molecular Weight Polyethylene Low-Entangled Films with Reserved Shish Crystals During Hot Stretching

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2024年第8期42卷 1227-1242页

作者： Jia-Wei Gao li Chen Ye-Shun Zhong Chao-Wei Xing yi-Guo li Zong-Bao Wang School of Materials Science and Chemical Engineering Ningbo UniversityNingbo 315211China

Shish crystals are crucial to achieving high performance low-dimensional ultra-high molecular weight polyethylene(UHMWPE)***,high stretch and shear flow fields are necessary for the formation of shish *** this study,UHMWPE gel films with reserved shish crystals were prepared by gel molding,the structural evolution and properties of UHMWPE films stretched at temperatu res of 100,110,120and 130℃were investigated by in situ small-angle X-ray scattering(SAXS)/ultra-small-angle X-ray scattering(USAXS)/wide-angle X-ray diffraction(WAXD)measu rements as well as scanning electron microscopy(SEM)and differential scanning calorimetry(DSC)*** findings showed that the reserved shish crystals can facilitate the formation and structural evolution of shish-kebab crystals during the hot ***,the reserved shish crystals promote the structu ral evolution of UHMWPE films to a greater extent when stretched at 120 and 130℃,compared to 100 and 110℃,resulting in higher crystallinity,orientation,thermal properties,breaking strength and Young's *** pared to UHMWPE high-entangled films with reserved shish crystals prepared by compression molding,UHMWPE low-entangled films with reserved shish crystals prepared by gel molding are more effective in inducing the formation and evolution of shish-kebab crystals during the hot stretching,resulting in increased breaking strength and Young's modulus.

关键词： UHMWPE low-entangled films Reserved shish crystals Structural evolution Hot stretching