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Regional Variation in Carbon Sequestration Potential of Forest Ecosystems in China

Chinese Geographical Science 2017年第3期27卷 337-350页

作者： XU Li WEN Ding zhu Jianxing HE Nianpeng Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of ScienceBeijing 100101China University of Chinese Academy of Sciences Beo'ing 10049China

Enhancing forest carbon(C) storage is recognized as one of the most economic and green approaches to offsetting anthropogenic CO_2 emissions. However, experimental evidence for C sequestration potential(C_(sp)) in China's forest ecosystems and its spatial patterns remain unclear, although a deep understanding is essential for policy-makers making decisions on reforestation. Here, we surveyed the literature from 2004 to 2014 to obtain C density data on forest ecosystems in China and used mature forests as a reference to explore C_(sp). The results showed that the C densities of vegetation and soil(0–100 cm) in China's forest ecosystems were about 69.23 Mg C/ha and 116.52 Mg C/ha, respectively. In mature forests, the C_(sp) of vegetation and soil are expected to increase to 129.26 Mg C/ha(87.1%) and 154.39 Mg C/ha(32.4%) in the coming decades, respectively. Moreover, the potential increase of C storage in vegetation(10.81 Pg C) is estimated at approximately twice that of soil(5.01 Pg C). Higher C_(sp) may occur in the subtropical humid regions and policy-makers should pay particular attention to the development of new reforestation strategies for these areas. In addition to soil nutrients and environment, climate was an important factor influencing the spatial patterns of C density in forest ecosystems in China. Interestingly, climate influenced the spatial patterns of vegetation and soil C density via different routes, having a positive effect on vegetation C density and a negative effect on soil C density. This estimation of the potential for increasing forest C storage provided new insights into the vital roles of China's forest ecosystems in future C sequestration. More importantly, our findings emphasize that climate constraints on forest C sequestration should be considered in reforestation strategies in China because the effects of climate were the opposite for spatial patterns of C density in vegetation and *** forest carbon(C) storage is recognized

关键词： carbon density forest reforestation storage sequestration potential

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Digital Watermark-based Security Technology for Geo-spatial Graphics Data

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Chinese Geographical Science 2006年第3期16卷 276-281页

作者： JIA Peihong CHEN Yunzhen MA Jinsong zhu Dakui The Key Laboratory of Coast ＆ Inland Development of Ministry of Education Nanjing UniversityNanjing 210093China Jiangsu Provincial Survey Bureau Nanjing 210013China

The paper presents a set of techniques of digital watermarking by which copyright and user rights messages are hidden into geo-spatial graphics data,as well as techniques of compressing and encrypting the watermarked geo-spatial graphics *** technology aims at tracing and resisting the illegal distribution and duplication of the geo-spatial graphics data product,so as to effectively protect the data producer＇s rights as well as to facilitate the secure sharing of geo-spatial graphics *** far in the CIS field throughout the world,few researches have been made on digital *** research is a novel exploration both in the field of security management of geo-spatial graphics data and in the applications of digital watermarking *** application software employing the proposed technology has been developed.A number of experimental tests on the 1：500,000 digital bathymetric chart of the South China Sea and 1：10,000 digital topographic map of Jiangsu Province have been conducted to verify the feasibility of the proposed technology.

关键词： geo-spatial graphics data copyright protection digital watermarking stego carrier data encrypting

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Effect of Annealing and Hot Rolling on Grain Boundary Segregation of Arsenic in an Mn-Steel Microalloyed by Ti,Cr and Nb

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Journal of Iron and Steel Research International 2013年第9期20卷 67-72页

作者： zhu Yuan-zhi LI Bing-liang LIU Ping College of Mechanical Electronical and Engineering North China University of Technology Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education Wuhan University of Science and Technology

Steel samples with size of 10 mm× 10 mm×5 mm were cut clown from a hot rolled Mn steel microalloyed by Ti, Cr and Nb and produced by compact strip production （CSP） technology. The samples were annealed at 950 ℃ for different time firstly, and then hot rolled or cooled in the air, in water and in furnace, respectively. Auger elee tron spectroscopy （AES） was used to study the effects of annealing and hot roiling on the segregation of arsenic at grain boundary （GB） in the steel. The results indicated that a higher content of arsenic was found at grain boundaries than in the matrix when the steel was annealed at 950 ℃ for 2 h and then cooled to room temperature by water quenching. But the content of arsenic at grain boundaries was similar to that in the matrix when the steel was an- nealed at 950 ℃ for 2 h and then cooled to room temperature by furnace cooling. A longer holding time, such as 12 h and 36 h at 950 ℃, resulted in a similar arsenic content at grain boundaries to that in the matrix of the steels. Hot rolling led to a similar content of arsenic at grain boundaries and within grains in the steels as well.

关键词： arsenic grain boundary segregation heat treatment roiling Mn-steel

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Effect of Friction on Dynamic Response of A Power Split Transmission System

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Transactions of Nanjing University of Aeronautics and Astronautics 2019年第3期36卷 387-400页

作者： JIN Guanghu YANG Haoyun LU Fengxia zhu Rupeng National Key Laboratory of Science and Technology on Helicopter Transmission Nanjing University of Aeronautics and Astronautics

The tooth surface friction stiffness and friction torque coefficient equations of cylindrical gear are *** the basis of factors such as time varying friction coefficient and mesh stiffness,support stiffness,torsional stiffness and comprehensive error,the dynamic equations of the gear trains with bending torsional coupling are *** the Fourier series method,the total response of the system is obtained,and the influence of friction on it is *** results show that when the spur gear enters the meshing,the frictional amplitude of the tooth surface is larger than that of the gear when it is withdrawn from engagement,and the meshing force fluctuates *** frictional force and dynamic meshing force of the herringbone gear tooth surface are relatively stable,and the fluctuation amplitude is much smaller than that of the spur *** amplitude of the bearing vibration is not affected by the friction,but the friction has a certain influence on the bearing force of the output *** first order natural frequency of the split stage and the power confluence stage has a large influence on the vibration of the bearing *** general,the natural frequency of the power confluence stage has a large proportion of influence.

关键词： gear split torque friction dynamic response

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Mutant Huntingtin Causes a Selective Decrease in the Expression of Synaptic Vesicle Protein 2C

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Neuroscience Bulletin 2018年第5期34卷 747-758页

作者： Chaohua Peng Gaochun zhu Xiangqian Liu He Li Department of Histology and Embryology School of Basic Medicine Tongji Medical College Huazhong University of Science and Technology Key Laboratory of Ministry of Education of China for Neurological Disorders Tongji Medical College Huazhong University of Science and Technology

Huntington＇s disease （HD） is a neurodegenera- tive disease caused by a polyglutamine expansion in the huntingtin （Htt） protein. Mutant Htt causes synaptic transmission dysfunctions by interfering in the expression of synaptic proteins, leading to early HD symptoms. Synaptic vesicle proteins 2 （SV2s）, a family of synaptic vesicle proteins including 3 members, SV2A, SV2B, and SV2C, plays important roles in synaptic physiology. Here, we investigated whether the expression of SV2s is affected by mutant Htt in the brains of HD transgenic （TG） mice and Neuro2a mouse neuroblastoma cells （N2a cells） expressing mutant Htt. Western blot analysis showed that the protein levels of SV2A and SV2B were not signifi- cantly changed in the brains of HD TG mice expressing mutant Htt with 82 glutamine repeats. However, in the TG mouse brain there was a dramatic decrease in the protein level of SV2C, which has a restricted distribution pattern in regions particularly vulnerable in HD. Immunostaining revealed that the immunoreactivity of SV2C was progres- sively weakened in the basal ganglia and hippocampus of TG mice. RT-PCR demonstrated that the mRNA level of SV2C progressively declined in the TG mouse brain without detectable changes in the mRNA levels of SV2A and SV2B, indicating that mutant Htt selectively inhibits the transcriptional expression of SV2C. Furthermore, we found that only SV2C expression was progressively inhibited in N2a cells expressing a mutant Htt containing 120 glutamine repeats. These findings suggest that the synaptic dysfunction in HD results from the mutant Htt- mediated inhibition of SV2C transcriptional expression. These data also imply that the restricted distribution and decreased expression of SV2C contribute to the brain region-selective pathology of HD.

关键词： Synaptic vesicle protein 2C Huntington'sdisease Basal ganglia Hippocampus

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A study on mechanical properties of equal wall thickness rubber bushing of positive displacement motor based on hydrogenated nitrile butadiene rubber aging test

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Petroleum 2022年第3期8卷 403-413页

作者： Changshuai Shi Xiaofeng Wan Xiaohua zhu Kailin Chen Department of Mechatronic Engineering Southwest Petroleum UniversityChengdu610500PR China

Shale gas production has become the main driver of global gas production *** shale gas is difficult to extract,which puts forward higher requirements for drilling speed *** downhole power drilling tools are mainly screw drilling *** screw drill tool stator bushing has poor heat dissipation,which is prone to thermal hysteresis failure,shortening drilling tool life,and is not suitable for high temperature and high pressure environment of deep shale gas *** wall thickness screw drilling tools and hydrogenated nitrile rubber have better high temperature ***,based on the thermal aging experiment and constitutive model of the rubber changes the displacement of the inner cavity of the stator bushing and the difference between the front and the back is up to 21.6%.The increase of the interference and eccentricity between rotor and motor leads to the increase of the maximum von Mises stress of the stator bushing and the thermal hysteresis *** influence of the interference is greater than the influence of the eccentricity so that the interference should be given priority in the *** paper provides a theoretical reference for the design and optimization of equal wall thickness bushing of positive displacement motor.

关键词： PDM HNBR Constitutive model Thermal hysteresis Numerical simulation

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An assessment framework for branch parameter estimation of power systems

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Science China(Technological Sciences) 2012年第6期55卷 1631-1643页

作者： zhu JianQuan LIU Feng MEI ShengWei HE GuangYu State Key Laboratory of Power Systems Department of Electrical EngineeringTsinghua UniversityBeijing I00084China

This paper proposes an assessment framework for branch parameter estimation of power systems,based on which the estimation accuracy can be improved and the estimation reliability can be *** proposed framework comprises three parts:1) Parameter credibility assessment to evaluate the credibility of original parameters in the case that their true values are unknown;2) estimation accuracy assessment to provide quantitative information about the validity of the estimation;3) parameter dominance assessment to find out the key parameters for the *** framework can be incorporated into the conventional parameter estimation process easily such that the accuracy and reliability of the estimation are *** implementation problems are addressed in *** are carried out on the IEEE 14-bus system,IEEE 30-bus system,and IEEE 300-bus system to show the correctness and effectiveness of the proposed assessment framework.

关键词： power systems assessment branch parameter estimation

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Diffusion occupation time before exiting

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Frontiers of Mathematics in China 2014年第4期9卷 843-861页

作者： Yingqiu LI Suxin WANG Xiaowen ZHOU Na zhu College of Mathematics and Computing Sciences Changsha University of Science and Technology Changsha 410004 China College of Mathematics Nankai University Tianjin 300071 China Department of Mathematics and Statistics Concordia University MontrealQuebec H3G 1M8 Canada

Using the approach of D. Landriault et al. and B. Li and X. Zhou, for a one-dimensional time-homogeneous diffusion process X and constants c 〈 a 〈 b 〈 d, we find expressions of double Laplace transforms of the form Ex[e--θTd--λ∫o Td1a 〈Xs〈b ds; Td 〈 Tc], where Tx denotes the first passage time of level x. As applications, we find explicit Laplace transforms of the corresponding occupation time and occupation density for the Brownian motion with two-valued drift and that of occupation time for the skew Ornstein- Uhlenbeck process, respectively. Some known results are also recovered.

关键词： Diffusion exit problem occupation time occupation density localtime Brownian motion with two-valued drift skew Ornstein-Uhlenbeck (OU)process

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Seismic stability and permanent displacement of landfill along liners

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Science China(Technological Sciences) 2008年第4期51卷 407-423页

作者： CHEN YunMin GAO Deng zhu Bin CHEN RenPeng MOE Key Laboratory of Soft Solis and Geoenvironmental Engineering Zhejiang UniversityHangzhou 310027China

The three-part wedge limit equilibrium method for seismic stability analysis of the landfill along liners is presented. The approximate solutions of the factor of safety and the yield acceleration coefficient are obtained. Parametric studies show that the interface strength of liners, the shear strength of waste and the height of retaining wall can influence the seismic stability of landfill along liners. The density and the shear wave velocity of the field waste are obtained by the borehole investigation and the spectral analysis of surface wave (SASW), respectively. The strain-dependent shear modulus and damping ratio of the artifical waste are obtained by the moderate-scale dynamic triaxial tests. The onedimensional (1D) equivalent linear dynamic response analysis is used to calculate the horizontal equivalent seismic coefficient-time history of the sliding landfill during earthquake. The seismic permanent displacement of the landfill along liners with different site conditons and heights is evaluated by the Newmark method. The catculated results show that ratio of ky /kmax, site conditions, the amplitude and frequency content of the bedrock motion can affect the seismic permanent displacement of the landfill along liners in some degree. Finally, the seismic stability and permanent displacements of three expanded configurations of a certain landfill case are analyzed.

关键词： landfill liner seismic stability permanent displacement Newmark method

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Reputation-based secure spectrum situation fusion in distributed cognitive radio networks

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The Journal of China Universities of Posts and Telecommunications 2015年第3期22卷 110-117页

作者： Li Fangwei Liu Fan zhu Jiang Nie Yifang School of Communication and Information Engineering Chongqing University of Posts and Telecommunications

In distributed cognitive radio （CR） network, the cooperative spectrum situation sensing based on consensus scheme may be disrupted by spectrum sensing data falsification （SSDF） attacks. In this paper, a secure spectrum situation fusion scheme based on reputation is proposed to counter attacks. The neighboring nodes of secondary users （SUs） get the corresponding dynamic trust value according to their behavior, which restrict the impact of the malicious behavior on the premise to ensure information interaction of normal nodes. Theoretical analysis and simulation results show that the consensus fusion scheme based on reputation has better performance than the existing algorithm which eliminates the neighboring node with the biggest deviation value from mean value. It demonstrates that the proposed scheme not only achieves better convergence properties but also has higher detection probability than the existing scheme in the process of spectrum situation fusion.

关键词： cognitive radio spectrum situation fusion secure consensus spectrum sensing data falsification (SSDF) attack

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