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施氮水平对水稻生育后期地上部氨挥发的影响

应用生态学报 2008年第7期19卷 1483-1488页

作者：陈刚徐阳春沈其荣南京农业大学资源与环境科学学院南京210095

采用温室盆栽模拟试验,研究了不同施氮水平下水稻开花后地上部氨挥发及其影响因素.结果表明:不同品种水稻开花后地上部日氨挥发量和开花至成熟期的氨挥发总量均随施氮量的增加而增加,且不同施氮水平间存在一定差异.花期和成熟期水稻地... 详细信息

采用温室盆栽模拟试验,研究了不同施氮水平下水稻开花后地上部氨挥发及其影响因素.结果表明:不同品种水稻开花后地上部日氨挥发量和开花至成熟期的氨挥发总量均随施氮量的增加而增加,且不同施氮水平间存在一定差异.花期和成熟期水稻地上部氨挥发量(y)与功能叶片谷氨酰胺合成酶(GS)活性(x1)呈显著负相关,而与功能叶片质外体NH4+浓度(x2)呈显著正相关:y=-0.37846x1+0.41821x2+0.04925(R2=0.9471,n=16).水稻氮素收获指数(x1)和氮肥生理利用率(x2)均与地上部氨挥发总量(y)呈显著负相关:y=-0.02117x1+0.75186(R2=0.8426,n=8)和y=-1.10386x2+35.52676(R2=0.8489,n=8),说明高氮水平下水稻氮肥利用率的下降与水稻地上部氨挥发量的增加有关.

关键词：水稻地上部氨挥发氮肥利用率谷氨酰胺合成酶活性质外体NH4^+浓度

小麦和玉米叶面标记尿素态^(15)N的吸收和运输

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土壤学报 2001年第1期38卷 67-74页

作者：沈其荣徐国华南京农业大学资源与环境科学学院

以15N标记的尿素作为叶面施肥和根系后期追肥的N肥品种，分别采用土培与砂培研究小麦与玉米拔节后至灌浆初期不同生育期、不同N、P和K肥叶面配施后作物对叶面N肥利用效率、叶面施用N肥的分配及对全株N、P和K养分状况的影响。无论是小麦... 详细信息

以15N标记的尿素作为叶面施肥和根系后期追肥的N肥品种，分别采用土培与砂培研究小麦与玉米拔节后至灌浆初期不同生育期、不同N、P和K肥叶面配施后作物对叶面N肥利用效率、叶面施用N肥的分配及对全株N、P和K养分状况的影响。无论是小麦还是玉米叶片均能有效地吸收N素并将其迅速转移。玉米拔节期下位叶（第5叶）施肥，植株吸收的15N转移到根部的比例平均为9.0%，而中位叶（第8叶）处理，分配到根系的比例仅为2.4%。叶面施用尿素态氮肥的N在小麦地上部的回收率一般在54.5%～68.9%，在玉米全株体内的回收率可达59.9%～75.3%。随生育期推迟，两种作物叶片吸收N的回收利用率均明显提高。与单施氮肥相比，N，P和K肥配施均有提高氮素回收率和改善作物地上部N素营养的作用，尤以中位叶（第8叶）配施尿素＋KH2PO4的效果最佳，表明植物的叶面营养仍应注意平衡供应和适宜的施用时期与施肥部位。叶面大量元素营养不仅改善了所施肥料成分中相应元素的营养状况，同时也促进了对其他两种成分的吸收，并且提高了N、P转运到籽粒中去的比例。玉米吐丝期根系追施的尿素态N有56%积累在籽粒中，而叶面施肥所利用的N分配在籽粒中的比例为70%。

关键词：同位素示踪法尿素小麦玉米叶面营养众吸收利用效率

Magnetic properties and magnetocaloric effects in Eu(Ti,Nb,Mn)O_(3) perovskites

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Journal of Rare Earths 2024年第8期42卷 1560-1567,I0006页

作者： Junfeng Wang Huicai Xie Quanyi Liu Zhihong Hao Zhaojun Mo qi Fu Xinqiang Gao Jun shen Ganjiang Innovation Academy Chinese Academy of SciencesGanzhou341119China Faculty of Materials Metallurgy and Chemistry Jiangxi University of Science and TechnologyGanzhou341000China School of Rare Earth and New Materials Engineering Gannan University of Science and TechnologyGanzhou341000China Department of Energy and Power Engineering School of Mechanical EngineeringBeijing Institute of TechnologyBeijing100081China

In perovskite EuTiO_(3),the magnetic characteristics and magnetocaloric effect(MCE) can be flexibly regulated by converting the magnetism from antiferromagnetic to *** the present work,a series of Eu(Ti,Nb,Mn)O_(3) compounds,abbreviated as ETNMO for convenience of description,was fabricated and their crystallography,magnetism together with cryogenic magnetocaloric effects were systematically *** crystallographic results demonstrate the cubic perovskite structure for all the compounds,with the space group of *** magnetic phase transitions are observed in these second-order phase transition(SOPT) *** joint substitution of elements Mn and Nb can considerably manipulate the magnetic phase transition process and magnetocaloric performance of the ETNMO *** the Mn content increases,gradually widened-ΔS_(M)-T curves are obtained,and two peaks with a broad shoulder are observed in the-ΔS_(M)-T curves for Δμ_(0)H≤0-1 *** a field change of 0-5 T,the values of maximum magnetic entropy change(-ΔS_(M)^(max)) and refrigeration capacity(RC) are evaluated to be 34.7 J/(kg·K) and 364.9 J/kg for EuTi_(0.8625)Nb_(0.0625)Mn_(0.075)O_(3), 27.8 J/(kg·K) and367.6 J/kg for EuTi_(0.8375)Nb_(0.0625)Mn_(0.1)O_(3),23.2 J/(kg·K) and 369.2 J/kg for EuTi_(0.8125)Nb_(0.0625)Mn_(0.125)O_(3),17.1 J/(kg·K) and 357.6 J/kg for EuTi_(0.7875)Nb_(0.0625)Mn_(0.15)O_(3),*** co nsiderable MCE parameters make the ETNMO compounds potential candidates for cryogenic magnetic refrigeration.

关键词： ETNMO perovskites Cryogenic refrigeration Magnetic phase transition Magnetocaloric effect Rare earths

Model Establishment for Simulating Soil Organic Carbon Dynamics

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Journal of Integrative Agriculture 2002年第3期 72-77页

作者： HUANG Yao, LIU Shi-liang, shen qi-rong and ZONG Liang-gang ( College of Resource and Environmental Sciences , Nanjing Agricultural University, Nanjing 210095 Institute of Atmospheric Physics , Chinese Academy of Sciences , Beijing 100029 )

Assuming that decomposition of organic matter in soils follows the first-order kinetics reaction, a computer model was developed to simulate soil organic matter dynamics. Organic matter in soils is divided up into two parts that include incorporated organic carbon from crop residues or other organic fertilizer and soil intrinsic carbon. The incorporated organic carbon was assumed to consist of two components, labile-C and resistant-C. The model was represented by a differential equation of dCt/dt = Kt × fr × fw × fs × ct (i = 1, r,S) and an integral equation of Cit = Cio × EXP(Ki × fT × fw × fs × t). Effect of soil parameters of temperature, moisture and texture on the decomposition was functioned by the fT, fw and fs, respectively. Data from laboratory incubation experiments were used to determine the first-order decay rate K, and the fraction of labile-C of crop residues by employing a nonlinear method. The values of K for the components of labile-C and resistant-C and the soil intrinsic carb

关键词： Agricultural soils Organic carbon Decomposition Simulation model

Variational Reconstruction and Simulation Experiments of Sea Surface Wind Field for Ocean Data Buoy

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Journal of Ocean University of China 2024年第3期23卷 577-582页

作者： LI Yunzhou HUANG Sixun YAN shen SUN Xuejin qi Suiping WANG Zhongqiu TANG Xiaoyu College of Meteorology and Oceanography National University of Defense TechnologyChangsha 410073China Institute of Oceanographic Instrumentation Qilu University of Technology(Shandong Academy of Sciences)Qingdao 266061China State Key Laboratory of Industrial Control Technology College of Control Science and EngineeringZhejiang UniversityHangzhou 310027China Laoshan Laboratory Qingdao 266237China

The sea surface wind field is an important physical parameter in oceanography and *** the continuous refinement of numerical weather prediction,air-sea interface materials,energy exchange,and other studies,three-dimensional(3D)wind field distribution at local locations on the sea surface must be measured *** current in-situ observation of sea surface wind parameters is mainly achieved through the installation of wind sensors on ocean data ***,the results obtained from this single-point measurement method cannot reflect wind field distribution in a vertical direction above the sea ***,the present paper proposes a theoretical framework for the optimal inversion of the 3D wind field structure variation in the area where the buoy is *** variation analysis method is first used to reconstruct the wind field distribution at different heights of the buoy,after which theoretical analysis verification and numerical simulation experiments are *** results indicate that the use of variational methods to reconstruct 3D wind fields is significantly effective in eliminating disturbance errors in observations,which also verifies the correctness of the theoretical analysis of this *** findings of this article can provide a reference for the layout optimization design of wind measuring instruments in buoy observation systems and also provide theoretical guidance for the design of new observation buoys in the future.

关键词： moored buoy three-dimensional wind field distribution variational analysis wind field reconstruction

Vibration Suppression for Active Magnetic Bearings Using Adaptive Filter with Iterative Search Algorithm

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CES Transactions on Electrical Machines and Systems 2024年第1期8卷 61-71页

作者： Jin-Hui Ye Dan Shi Yue-sheng qi Jin-Hui Gao Jian-Xin shen IEEE Department of Electrical Engineering Zhejiang UniversityHangzhou 310027China CES and IEEE

Active Magnetic Bearing(AMB) is a kind of electromagnetic support that makes the rotor movement frictionless and can suppress rotor vibration by controlling the magnetic force. The most common approach to restrain the rotor vibration in AMBs is to adopt a notch filter or adaptive filter in the AMB controller. However, these methods cannot obtain the precise amplitude and phase of the compensation current. Thus, they are not so effective in terms of suppressing the vibrations of the fundamental and other harmonic orders over the whole speed range. To improve the vibration suppression performance of AMBs,an adaptive filter based on Least Mean Square(LMS) is applied to extract the vibration signals from the rotor displacement signal. An Iterative Search Algorithm(ISA) is proposed in this paper to obtain the corresponding relationship between the compensation current and vibration signals. The ISA is responsible for searching the compensating amplitude and shifting phase online for the LMS filter, enabling the AMB controller to generate the corresponding compensation force for vibration suppression. The results of ISA are recorded to suppress vibration using the Look-Up Table(LUT) in variable speed range. Comprehensive simulations and experimental validations are carried out in fixed and variable speed range, and the results demonstrate that by employing the ISA, vibrations of the fundamental and other harmonic orders are suppressed effectively.

关键词： Active Magnetic Bearing(AMB) Adaptive filter Iterative search algorithm Least mean square(LMS) Vibration suppression

Ordered Bicontinuous Network Structures Regulated by Orientational Interactions in a Rod-Coil Block Copolymer

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Chinese Journal of Polymer Science 2024年第5期42卷 636-642,I0008页

作者： Xiao-Lin Lyu Shi-Chu Yang An-qi Xiao Ping-Ping Hou Wei Zhang Hong-Bing Pan Zhi-Hao shen Xing-He Fan qi-Feng Zhou Beijing National Laboratory for Molecular Sciences Key Laboratory of Polymer Chemistry and Physics of Ministry of EducationCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing100871China Key Laboratory of Advanced Materials Technologies International(HongKong Macao and Taiwan)Joint Laboratory on Advanced Materials TechnologiesCollege of Materials Science and EngineeringFuzhou UniversityFuzhou350108China

The rich phase behavior of block copolymers(BCPs)has drawn great attention in recent ***,the double diamond(DD)phase is rarely obtained because of the competition between the minimization of interfacial energy and packing ***,a rod-coil BCP containing mesogen-jacketed liquid crystalline polymer is designed to acquire ordered bicontinuous network *** reduction of internal energy originating from the orientational interaction among the rod blocks can compensate for the free energy penalty of packing frustration to stabilize the DD *** resulting BCP can also experience lamellae-to-DD and double gyroid-to-lamellae transitions by changing the annealing *** results make the rod-coil BCP an excellent candidate for the self-assembly of ordered network structures,demonstrating great potential in nanopatterning and metamaterials.

关键词： Block copolymer Rod-coil Ordered bicontinuous phase Double diamond Double gyroid

Bilayer Compounded Polytetrafluoroethylene Membrane for Enhanced Oil-Water Emulsion Separation

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Chinese Journal of Polymer Science 2024年第6期42卷 838-850页

作者： Yu-Liang Yang Tai-Ran Zhang Yan-Ting Han Shao-Yun Guo qin-Gong rong Jia-Bin shen State Key Laboratory of Polymer Materials Engineering Polymer Research Institute of Sichuan UniversitySichuan Provincial Engineering Laboratory of Plastic/Rubber Complex Processing TechnologyChengdu610065China West China Hospital/West China School of Nursing Sichuan UniversityChengdu610041China Shandong Senrong New Materials Co. Ltd.Zibo256401China

In order to achieve efficient and durable oil-water emulsion separation,the membranes possessing high separation efficiency and mechanical strength attract extensive attention and are in great *** present study,a kind of polytetrafluoroethylene(PTFE)-based bilayer membrane was fabricated by electrospinning fibrous PTFE(fPTFE)on an expanded PTFE(ePTFE)*** morphological observation revealed that the fibrous structure of the fPTFE layer could be tailored by controlling the formulation of spinning *** addition of appropriate polyoxyethylene(PEO)would make the fibers in the fPTFE layer finer and more *** a result,the compounded membrane exhibited a small pore size of approximately 1.25µm and a substantial porosity nearing 80%.This led to super-hydrophobicity,characterized by a high water contact angle(WCA)of 149.8°,and facilitated rapid oil *** water-in-oil emulsion separation experiment further confirmed that the compounded membrane not only had a high separation efficiency closing 100%,but such an outstanding separation capacity could be largely retained,either through multiple cycles of use or through strong acid(pH=1),strong alkali(pH=12),or high-temperature(100°C)***,the mechanical behavior of the bilayer membrane was basically contributed by that of each layer in terms of their volume *** significantly,the poor creep resistance of fPTFE layer was suppressed by compounding with ePTFE ***,this study has laid the groundwork for a novel approach to create PTFE-based compounded membranes with exceptional overall characteristics,showing promise for applications in the realm of emulsion separation.

关键词： ePTFE Electrospinning membrane Bilayer compounding Emulsion separation

Heat management technology for solid-state high voltage and high repetitive pulse generators:Towards better effects and reliability

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High Voltage 2024年第1期9卷 2-21页

作者： Yanan Wang Linyuan Ren Zihao Yang Saikang shen Zichen Deng qi Yuan Weidong Ding Zhenjie Ding School of Electrical Engineering Xi'an Jiaotong UniversityXi'anChina School of Electronic and Information Engineering Xi'an Jiaotong UniversityXi'anChina

Solid-state high voltage high repetitive pulse generators have a broad prospect in various *** high power and high-frequency operation of the pulse generator suffer from the massive heat dissipation problem,which limits the improvement of the output parameters and even affects the *** article focuses on heat management technology for high voltage high repetitive pulse ***,the typical circuit topology of the high repetitive pulse generators was *** the perspective of different application requirements,the demands of the heat management design were ***,the heat generation characteristics and difficulties of solid-state high voltage high repetitive pulse generators were ***,the different stateof-art cooling techniques were reviewed,and their applicability and limitations for the high voltage high repetitive generators were ***,a flow chart for heat management design was given.

关键词： pulse state high