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Spatio-Temporal Effect on Soil Respiration in Fine-Scale Patches in a Desert Ecosystem

Pedosphere 2006年第1期16卷 1-9页

作者： S. pen-MoURAToV M. RAKHIMBAEV Y. STEINBERGER Faculty of Life Sciences Bar-Ilan University Ramat-Gan 52900 (Israel) Faculty of Life Sciences Bar-Ilan University Ramat-Gan 52900 (Israel) Institute of Botany Tashkent (Uzbekistan)

Soil organisms in terrestrial systems are unevenly distributed in time and space, and often aggregated. Spatiotemporal patchiness in the soil environment is thought to be crucial for the maintenance of soil biodiversity, providing diverse microhabitats tightly interweaving with resource partitioning. Determination of a ＂scale unit＂ to help understand ecological processes has become one of the important and most debatable problems in recent years. A fieldwork was carried out in the northern Negev Desert highland, Israel to determine the influence of fine-scale landscape patch moisture heterogeneity on biogeochemical variables and microbial activity linkage in a desert ecosystem. The results showed that the spatio-temporal patchiness of soil moisture to which we attribute influential properties, was found to become more heterogenic with the decrease in soil moisture availability （from 8.2 to 0.4 g kg^-1） toward the hot, dry seasons, with coefficient of variation （CV） change amounting to 66.9%. Spatio-temporal distribution of organic matter （oM） and total soluble nitrogen （TSN） was found to be relatively uniformly distributed throughout the wet seasons （winter and spring）, with increase of relatively high heterogeneity toward the dry seasons （from 0.25% to 2.17% for oM, and from 0 to 10.2 mg kg^-1 for TSN） with CV of 47.4% and 99.7% for oM and TSN, respectively. Different spatio-temporal landscape patterns were obtained for Ca （CV = 44.6%）, K （CV = 34.4%）, and Na （CV = 92%） ions throughout the study period. Co2 evolution （CV = 48.6%） was found to be of lower heterogeneity （varying between 2 and 39 g Co2-C g^-1 dry soil h^-1） in the moist seasons, e.g., winter and spring, with lower values of respiration coupled with high heterogeneity of Na^＋ and low levels of TSN and organic matter content, and with more homogeneity in the dry seasons （varying between 1 and 50 g Co2-C g^-1 dry soil h^-1）. our results elucidate the heterogeneity and complexity of desert system habitats

关键词： desert microbial respiration patchiness small-scale habitat soil

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微生物发酵饲料对羔羊生长性能、瘤胃发酵功能及菌群的影响

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饲料研究 2024年第11期47卷 18-23页

作者：张林吉任春芝任士飞张善芳邱良伟孙朋徐州生物工程职业技术学院江苏徐州221006 睢宁县畜牧兽医技术指导站江苏徐州221299

试验旨在研究微生物发酵饲料对羔羊生长性能、瘤胃发酵参数及菌群的影响。试验选择44只体重接近、健康的湖羊羔羊,随机分为4组,每组11个重复,每个重复1只羊。对照组饲喂基础饲粮,试验组分别饲喂添加2.5%、5.0%和10.0%微生物发酵饲料的... 详细信息

试验旨在研究微生物发酵饲料对羔羊生长性能、瘤胃发酵参数及菌群的影响。试验选择44只体重接近、健康的湖羊羔羊,随机分为4组,每组11个重复,每个重复1只羊。对照组饲喂基础饲粮,试验组分别饲喂添加2.5%、5.0%和10.0%微生物发酵饲料的饲粮。预试期1周,正式试验期6周。结果表明:与对照组相比,饲喂5.0%和10.0%的微生物发酵饲料可以显著提高羔羊的末重和平均日增重(Po1指数和Ace指数呈现先降低后升高的趋势,其中2.5%发酵饲料组羔羊瘤胃Chao1指数和Ace指数显著低于对照组(P<0.05)。与对照组相比,饲喂2.5%、5.0%和10.0%微生物发酵饲料可以显著增加羔羊瘤胃中瘤胃球菌_2菌属、琥珀酸菌属、普雷沃氏菌属1的相对丰度(P<0.05);饲喂5.0%和10.0%微生物发酵饲料可以显著增加瘤胃球菌_UCG-014菌属的相对丰度(P<0.05)。饲喂2.5%、5.0%和10.0%微生物发酵饲料可以显著增加羔羊瘤胃中放线菌门、厚壁菌门、拟杆菌门的相对丰度(P<0.05)。研究表明,饲喂5.0%微生物发酵饲料对提高羔羊生长性能、改善瘤胃发酵功能及菌群组成的效果较优。

关键词：发酵饲料微生物羔羊生长性能瘤胃发酵瘤胃菌群

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CAVITATIoN BEHAVIoR oF A NACA16-012 HYDRoFoIL

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Journal of Hydrodynamics 1993年第2期5卷 87-93页

作者： Huang, Jian-bo pen, Sen-sen Pong, Xiao-xin Chen, Bin East China Inst of Metallurgy Maanshan China

Numerical and experimental study is carried to investigate the cavitation behavior in the turbulent flow around a NACA16-012 hydrofoil. The Navier-Stokes Equations for compressible fluid are adopted to simulate the overall motion and dynamical characteristics of the cavity flow, while the bubble dynamics is used to calculate the motion and growth of nuclei inside the cavity. Cavitation experiment for the hydrofoil is carried out in a water tunnel of CSS-RC, the phenomenon in the experiment is recorded and analyzed with high speed photographic technique.

关键词： Bubble formation Cavitation Compressible flow Mathematical models Turbulent flow Water supply tunnels

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A formally verified transformation to unify multiple nested clocks for a Lustre-like language

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Science China(Information Sciences) 2019年第1期62卷 208-210页

作者： Gang SHI Yucheng ZHANG Shu SHANG Shengyuan WANG Yuan DoNG pen-Chung YEW Department of Computer Science and Technology Tsinghua University Department of Computer Science and Engineering University of Minnesota

Multiple nested clocks is a major language feature in synchronous data-flow languages such as Lustre [1]. To build a formally verified compiler for such a language, it is a common practice to compile the source program to a C-like program first before compiling it to low-level machine-dependent code using a formally verified backend compiler

关键词： A formally verified transformation to unify multiple nested clocks for a Lustre-like language cycle

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Finite element simulation of the micromachining of nanosized-silicon-carbide-particle reinforced composite materials based on the cohesive zone model

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Nanotechnology and Precision Engineering 2018年第4期1卷 242-247页

作者： Hongmin pen Jianhua Guo Zizhen Cao Xianchong Wang Zhiguo Wang Tianjin Institute of Aerospace Mechanical and Electrical Equipment Tianjin 300458China Tianjin Long March Technical Equipment Co.Ltd. Tianjin 300462China Guilin University of Aerospace Technology Guilin 541000China

A finite element method based on the cohesive zone model was used to study the micromachining process of nanosized silicon-carbide-particle(SiCp) reinforced aluminum matrix composites. As a hierarchical multiscale simulation method, the parameters for the cohesive zone model were obtained from the stress-displacement curves of the molecular dynamics simulation. The model considers the random properties of the siliconcarbide-particle distribution and the interface of bonding between the silicon carbide particles and the *** machining mechanics was analyzed according to the chip morphology, stress distribution, cutting temperature, and cutting force. The simulation results revealed that the random distribution of nanosized SiCp causes non-uniform interaction between the tool and the reinforcement particles. This deformation mechanics leads to inhomogeneous stress distribution and irregular cutting force variation.

关键词： Multiscale Cohesive zone model Nanosized silicon carbide particles Composite materials Micromachining

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Insights into the synergistic promotion of spin polarization over C_(3)N_(5.4) for enhancing cooperative hydrogen evolution and benzylamine oxidation coupling

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Nano Research 2023年第4期16卷 4225-4232页

作者： Qiuchen Wang Xiaoxu Deng Haiyan pen Fei Liu Meiyang Song peng Chen Shuang-Feng Yin Provincial Guizhou Key Laboratory of Green Chemical and Clean Energy Technology School of Chemistry and Chemical EngineeringGuizhou UniversityGuiyang 550025China College of Big Data and Information Engineering Guizhou UniversityGuiyang 550025China College of Chemistry and Chemical Engineering Advanced Catalytic Engineering Research Center of the Ministry of EducationState Key Laboratory of Chemo/Biosensing and ChemometricsHunan UniversityChangsha 410082China

Polymers are usually restricted on the high exciton binding energies and sluggish electron transfer because of the low dielectric *** spin-polarized electrons is regarded as an attractive strategy,but often confined to the d-orbital ***,the nonmetal P and N elements co-mediated the spin polarization of carbon nitrides(PCN)have been elaborately *** optimized PCN-3 shows an outstanding hydrogen production(22.2 mmol·g^(-1)·h^(-1))coupled with selective benzylamine oxidation without using any solvent and cocatalysts,which is 200 times of original C_(3)N_(4)and superior to the photocatalysts has been reported to *** and theoretical results verified that the spin-orbital coupling of N 2p and P 2p remarkably increased the parallel spin states of charge and reduced the formation of singlet excitons to accelerate exciton dissociation in carbon *** addition,charge separation and surface catalysis can be significantly enhanced by the electron spin polarization of carbon nitride with the parallel arrangement,huge built-in electric field and disturbed electronic *** finding deepens the insight into the charge separation and exciton dissociation in spin polarization,and offers new tactics to develop high-efficiency catalysts.

关键词： spin polarization photocatalysis amine oxidative coupling hydrogen production C_(3)N_(5.4)

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Diversity and Dynamics of Soil Free-Living Nematode Populations in a Mediterranean Agroecosystem

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Pedosphere 2005年第2期15卷 204-215页

作者： LIANGWen-Ju I.LAVIAN S.pen-MoURAToV Y.STEINBERGER FacultyofLifeSciences Bar-IlanUniversityRamat-Gan52900（Israel）.／／InstituteofAppliedEcologyChineseAcademyofSciencesShenyang110016（China） FacultyofLifeSciences Bar-IlanUniversityRamat-Gan52900（Israel）

To determine the effect of agricultural management on the dynamics and functional diversity of soil nematode communities in a carrot field at Kibbutz Ramat Hakovesh, Israel, soil samples from 0-10 cm and 10-20 cm depths were collected during the growing season of carrot. Indices were used to compare and assess the response of soil free-living nernatode communities to agricultural management. Eighteen nematode families and 20 genera were observed during the growing period, with Cephalobus, Rhabditidae, Aphelenchus, Tylenchus, and Dorylaimus being the dominant genera/families. During the planting, mid-season and post-harvest periods the total number of nematodes at both depths was significantly lower (P ot treatment than in the control plots, while during the harvest period at both depths total nematodes and bacterivores were significantly higher in the treatment plots (P of the maturity index (MI) at both depths were found to be significantly lower in the treatment plots than in the control plots during the pre-planting period (P overall, WI, MI and PPI were found to be more sensitive indicators than other ecological indices for assessing the response of nematode communities to agricultural management in a Mediterranean agroecosystem

关键词： agricultural management carrot-growing season diversity maturity index nematode community

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Micromagnetism simulation on effects of soft phase size on Nd2Fe14B/α-Fe nanocomposite magnet with soft phase imbedded in hard phase

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Chinese Physics B 2018年第8期27卷 529-534页

作者： Yu-Qing Li Ming Yue Yi pen Hong-Guo Zhang College of Materials Science and Engineering Beijing University of TechnologyBeijing 100124China

In this study, micromagnetism simulation by using timte dltterence method is cameo out on the Ncl21-el415/a-Fe nanocomposite magnet with soft phase imbedded in hard phase. The effects of soft magnetic phase size （S） on the magnetic properties and magnetic reversal modes are systematically analyzed. As S increases from 1 nm to 48 nm, the remanence （Jr） increases, while the coercivity （Hci） decreases, leading to the result that the magnetic energy prod- uct [（BH）max] first increases slowly, and then decreases rapidly, peaking at S = 24 nm with the （BH）max of 72.9 MGoe （1 MGoe = 7.95775 kJ.m-3）. Besides, with the increase of S, the coercivity mechanism of the nanocomposite magnet changes from nucleation to pinning. Furthermore, by observing the magnetic moment evolution in demagnetization pro- cess, the magnetic reversal of the soft phase in the nanocomposite magnet can be divided into three modes with the increase of S： coherent rotation （S 〈 3 nm）, quasi-coherent rotation （3 nm≤S 〈 36 nm）, and the vortex-like rotation （S ≥36 nm）.

关键词： micromagnetism simulation magnetization dynamics, Nd2Fe14B/a-Fe nanocomposite magnets

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Zno-chitosan/Rectorite Nanocomposite Exhibiting High Photocatalytic Activities under Visible-light Irradiation

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Journal of Wuhan University of Technology(Materials Science) 2020年第2期35卷 310-319页

作者： LI Shiqian pen-Chi Chiang DING Ling Kinjal JShah CHEN Qinghua CHEN Sheng College of ocean and Bio-chemical Engineering Fujian provincial Key Lab of Coastal Basin EnvironmentFuqing Branch of Fujian Normal UniversityFuqing 350300China Graduate Institute of Environmental Engineering National Taiwan UniversityTaipei City 10673TaiwanChina College of Chemistry and Chemical Engineering Wuhan University of Science and TechnologyWuhan 430081China College of Urban Construction Nanjing Tech UniversityNanjing 211800China Engineering Research Center of Polymer Green Recycling Ministry of Education(Fujian Normal University)Fuzhou 350007China

Chitosan(CS),hydrated zinc acetate,and rectorite(REC) were used as raw materials to prepare CS-embedded zinc oxide(Zno) nanoparticle by a chemical precipitation ***-bonded REC-loaded Zno-CS nanoparticle was to form Zno-CS/REC nanocomposite photocatalyst,its morphology and structure were analyzed by means of FTIR,XRD,TGA,SEM,and *** effects of the catalyst dosage,methyl orange(Mo) initial concentration and solution pH on photocatalytic performance were also *** experimental results show that the Zno-CS/REC nanocomposite has a particle size of 100 nm with good dispersion and *** irradiation of visible light,0.6 g/L photocatalyst was used to degrade Mo in solution for 90 min at pH 6,then the Mo solution(10 mg/L) was decolored by more than 99%,indicating that the Zno-CS/REC nanocomposite exhibited highly photocatalytic degradation ***,the photodegradation kinetic mechanism of Mo in aqueous solution is presumed.

关键词： Zno-Chitosan/rectorite nanocomposite visible-light methyl orange photodegradation

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Hybrid Hydrogels Toughened by Chemical Covalent Bonding and Physical Electrostatic Interactions

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Chemical Research in Chinese Universities 2018年第3期34卷 500-505页

作者： LIU Li PAN Ge WANG Licheng pen Xiuyan ZHANG Xinyue WU Guangfeng School of Chemical Engineering Changchun University of Technology Changehun 130012 P. R. China College of Chemistry Jilin University Changchun 130012 P. R. China

Polystyrene nanoparticles with negative charges（n-PSs） were synthesized using styrene（St） and sodium styrene sulfonate（NaSS） as initial materials by surfactant-free emulsion polymerization. Subsequently, a hybrid hydrogel was prepared using acrylamide（AAm） and methacryloyloxyethyltrimethyl ammonium chloride（DMC） as co-monomers with N,N＇-methylenebisacrylmnide（MBA） as a chemical crosslinker and n-PSs as a physical electrostatic interaction agent. The resulting hybrid hydrogels exhibited excellent tensile strength and elongation at break. The tensile stress of hybrid hydrogels was seven times greater than that ofhydrogels without n-PSs. The elongation at break of hydrogels reached 700%, which was much higher compared to those of the hydrogels without n-PSs. Furthermore, swelling measurements of the hydrogels indicate that there is an overshoot in the swelling process and the extent of overshoot decreases with the increasing n-PSs. Therefore, the work presented here provides a method for improving the mechanical properties of hydrogels via the introduction of polymeric nanoparticles.

关键词： Hydrogel Electrostatic interaction Mechanical property Swelling property

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