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Nitrogen isotopic composition of plant-soil in the Loess Plateau and its responding to environmental change

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Chinese science Bulletin 2009年第2期54卷 272-279页

作者： LIU WeiGuo1,2.& WANG Zheng1,3 1 State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of sciences, xi’an 710075, china 2.2., school of Human Settlement and Civil engineering, xi’an 710049, china 3 Graduate university of Chinese Academy of sciences, Beijing 100049, china Chinese Acad Sci Inst Earth Environm State Key Lab Loess and Quaternary Geol Xian 710075 Peoples R China.

The nitrogen isotope of soil is of emerging significance as an indicator of climatic change and biogeochemical cycle of nitrogen in nature systems. In this paper, the nitrogen content and isotopic composition of modern ecosystems from arid and semiarid Loess Plateau in northwestern china, including plant roots and surface soil, were determined to investigate trends in δ15N variation of plant roots and soil along a precipitation and temperature gradient in northwestern china under the East Asian Monsoon climate condition. The δ15N values of surface soil from the study area vary from ?1.2. to 5.8‰, but from -5.1‰ to 1.9‰ in the plant roots. Our results indicate that (1) although the isotopic compositions of both plant roots and surface soil change with a similar trend along the climate gradient, the apparent nitrogen difference between plant roots and soil existed, with -δ15N values ranging from 0.3‰ to 7.2. with average of 4.1‰; and (2. mean annual precipitation (MAP) is the dominant factor for isotopic composition of plant-soil nitrogen in the Loess Plateau, and the δ15N values are less correlated with MAT; we suggest that nitrogen isotopic composition of soil is a potential tracer for environmental changes.

关键词：氮同位素物理性质化学性质环境论

Fast feature-based mode decision for 4×4 intra prediction in H.2.4/AVC

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science china(Information sciences) 2011年第11期54卷 2386-2399页

作者： WANG Ping,HUANG Hua & TAN Zhengschool of Electronic and Information engineering,xi’an {2. university,xi’an 710049,china 1. school of Electronic and Information engineering Xi’an Jiaotong University Xi’an 710049 China

Intra coding in H.2.4/AVC can significantly improve the compression efficiency at the cost of high computational complexity due to the use of the rate-distortion optimization *** reduce the complexity of intra prediction,we propose a feature-based mode decision algorithm for 4×4 intra *** algorithm is motivated by the fact that a good prediction mode usually has a small residue block,which is the difference between the original block and predicted *** sum of the absolute transformed coefficients and deviation information of residue block are used to measure the distortion of prediction mode and the smoothness of residue block,*** to the ranking of these two features of all possible modes,and together with the most probable mode,small numbers of candidate modes can be ***,the candidate modes are further reduced to only one by using two early termination rules based on the correlation of rank and most probable *** results demonstrate that the proposed mode decision method reduces about 60% of total encoding time of intra coding with negligible loss of coding performance.

关键词： intra prediction mode decision H.2.4/AVC RDO

Optimal user scheduling and power control in multi-user cognitive broadcast systems

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science china(Information sciences) 2012年第6期55卷 1402-1414页

作者： WANG QunHuan 1,2.3,WANG HuiMing 1,2.3 & YIN QinYe 1,3 1 school of Electronic and Information engineering,xi'an {2. university,xi'an 710049,china 2.State Key Lab for Integrated Services Networks,xidian university,xi'an 710071,china 3 Ministry of Education Key Lab for Intelligent Networks and Network Security,xi'an {2. university,xi'an 710071,china. 1. school of Electronic and Information engineering Xi’an Jiaotong University Xi’an 710049 China2. State Key Lab for Integrated Services Networks Xidian University Xi’an 710071 China3. Ministry of Education Key Lab for Intelligent Networks and Network Security Xi’an Jiaotong University Xi’an 710071 China

Cognitive radio systems should not only have the ability to sense and exploit "frequency spectrum holes",but also the ability to sense and utilize "spatial spectrum holes".In this paper,we consider the issue of maximizing the throughput of the cognitive systems by fully utilizing "spatial spectrum holes" brought in by multiple cognitive users,in the scenario where a pair of licensed users and a cognitive broadcast system share multiple spectrum *** exploiting the channel reciprocity under the premise that the licensed system adopts the time-division-duplexing (TDD) mode,we propose a more practical cognitive access scheme that can sense the interference at the licensed user caused by the cognitive transmitter,based on the existing feedback signals from the licensed user to the licensed base *** both interferences from the licensed base station to the cognitive receiver and from the cognitive transmitter to the licensed user into consideration,we investigate the optimal user scheduling and power allocation scheme that can maximize the ergodic sum rate of the cognitive *** show that scheduling the user whose channel gain to interference and noise ratio (CGINR) is the largest for each frequency band is *** also derive the dynamic power allocation scheme meeting the three practical constraints,i.e.,the transmitter's average transmission power constraint,the power amplifier's instantaneous transmission power constraint,and the interference power constraint at the licensed *** result shows that in different coherent time intervals and different frequency bands,the power allocation has a multi-level waterfilling *** analysis shows that the strategy scheduling user with the largest CGINR introduces significant performance improvement compared with the traditional strategy scheduling user with the largest channel gain to noise ratio (CGNR).We also illustrate the impact of power constraints and the number of users on system p

关键词： cognitive radio distributed spatial spectrum holes opportunistic scheduling power allocation

Distribution Features of the Residual Stress For T-Joints by Laser Welding

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稀有金属材料与工程 2011年第S4期40卷 130-133页

作者： He Enguang1,Gong Shuili1,Wu Bing1,2.Chen Li1 1science and Technology on Power Beam Processes Laboratory,AVIC Beijing Aeronautical Manufacturing Technology Research Institute,Beijing 10002.,china 2.{2. of material science and engineering,xi`an jiaotong university,xi`an 710049,china AVIC Beijing Aeronaut Mfg Technol Res Inst Sci & Technol Power Beam Proc Lab Beijing 100024 Peoples R China xi An Jiao Tong Univ Sch Mat Sci & Engn Xian 710049 Peoples R China

The residual stress of T-joints for SUS304 stainless steel by YAG laser welding was measured by the method of hole-drilling,and the effects of heat treatment and hardness distribution of weld joints on the distribution of residual stress for T-joints were *** results showed that the maximum of longitudinal residual tensile stress for T-joints was about *** maximum of residual stress was not more than 40MPa after heat treatment,the peak of residual stress reduced *** gradient of residual stress distribution was also reduced *** hardening phenomenon occurred for T-joints,and the hardness of weld and heat affected zone was both higher than the hardness of base metal,the peak of hardness occurred in the fusion *** effect of strain hardening phenomenon of weld and heat affected zone on the residual stress distribution of T-joints for SUS304 stainless steel was obvious,which made longitudinal residual tensile stress become higher.

关键词： stainless steel laser welding T-joints heat treatment

The effects of the false vocal fold gaps on intralaryngeal pressure distributions and their effects on phonation

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science china(Life sciences) 2008年第11期51卷 1045-1051页

作者： LI Sheng1,2. WAN Mingxi1 & WANG SuPin1 1 Key Laboratory of Biomedical Information engineering of Ministry of Education, Department of Biomedical engineering, {2. of Life science and Technology, xi’an jiaotong university, xi’an 710049, china 2.Department of Biomedical engineering, Fourth Military Medical university, xi’an 710032. china 1. Key Laboratory of Biomedical Information engineering of Ministry of Education Department of Biomedical Engineering School of Life Science and Technology Xi’an Jiaotong University Xi’an 710049 China 2. Department of Biomedical engineering Fourth Military Medical University Xi’an 710032 China

Human phonation does not merely depend on the vibration of the vocal folds. Research by clinical and computer simulations has demonstrated that the false vocal fold (FVF) is an important laryngeal con-striction that plays a vital role during human voice production. This study explored the effects of the FVF gaps using both the three-dimensional Plexiglas model and the numerical computation methods. Twelve FVF gaps (ranging from 0.02.to 2.06 cm) were used in this study at three glottal angles (uniform and convergent/divergent 40°), two minimal glottal diameters (Dg) (0.04 cm and 0.06 cm) separately, and the constant subglottal pressure (8 cm H2.). The results suggested that (1) the intralaryngeal pressure was the lowest and the flow was the highest (least flow resistance) when the FVF gap was 1.5-2.times greater than Dg; (2. the divergent glottal angle gave lower pressure and greater flow than the conver-gent and uniform glottal angle as there were no FVF conditions; (3) the presence of the FVF decreased the effects of the glottal angle to a certain extent; and more importantly, (4) the presence of the FVF also moved the separation points downstream, straightened the glottal jet for a longer distance, decreased the overall laryngeal resistance, and reduced the energy dissipation, suggesting the significance of FVF in efficient voice production. These results may be incorporated in the phonatory models (physical or computational) for better understanding of vocal mechanics. The results might also be helpful in exploring the surgical and rehabilitative intervention of related voice problems.

关键词： false vocal fold laryngeal physical model aerodynamics modeling phonation

Oxidation behavior of FeV_(2.O_(4)and FeCr_(2.O_(4)particles in the air:Nonisothermal kinetic and reaction mechanism

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International Journal of Minerals,Metallurgy and materials 2024年第8期31卷 1839-1848页

作者： Junyi xiang xi Lu Luwei Bai Hongru Rao Sheng Liu Qingyun Huang Shengqin Zhang Guishang Pei Xuewei Lü school of Metallurgy and materials {2. Chongqing University of Science and TechnologyChongqing 401331China Department of materials science and {2. Seoul National UniversitySeoul 08826Rep.of Korea College of materials science and {2. Chongqing UniversityChongqing 400044China

High-temperature oxidation behavior of ferrovanadium(FeV_(2.O_(4))and ferrochrome(FeCr_(2.O_(4))spinels is crucial for the application of spinel as an energy material,as well as for the clean usage of high-chromium vanadium ***,the nonisothermal oxidation behavior of FeV_(2.O_(4)and FeCr_(2.O_(4)prepared by high-temperature solid-state reaction was examined by thermogravimetry and X-ray diffraction(XRD)at heating rates of 5,10,and 15 K/*** apparent activation energy was determined by the Kissinger-Akahira-Sunose(KAS)method,whereas the mechanism function was elucidated by the Malek ***,in-situ XRD was conducted to deduce the phase transformation of the oxidation mechanism for FeV_(2.O_(4)and FeCr_(2.O_(4).The results reveal a gradual increase in the overall apparent activation energies for FeV_(2.O_(4)and FeCr_(2.O_(4)during *** stages of the oxidation process are observed based on the oxidation conversion rate of each *** oxidation mechanisms of FeV_(2.O_(4)and FeCr_(2.O_(4)are complex and have distinct *** particular,the chemical reaction controls the entire oxidation process for FeV_(2.O_(4),whereas that for FeCr_(2.O_(4)transitions from a three-dimensional diffusion model to a chemical reaction *** to the in-situ XRD results,numerous intermediate products are observed during the oxidation process of both compounds,eventually resulting in the final products FeVO_(4)and V2._(5)for FeV_(2.O_(4)and Fe_(2.O_(3)and Cr_(2.O_(3)for FeCr_(2.O_(4),respectively.

关键词： FeV_(2.O_(4) FeCr_(2.O_(4) oxidation nonisothermal kinetics mechanism

Visualization of cristae and mtDNA interactions via STED nanoscopy using a low saturation power probe

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Light(science & Applications) 2024年第9期13卷 1741-1756页

作者： Wei Ren xichuan Ge Meiqi Li Jing Sun Shiyi Li Shu Gao Chunyan Shan Baoxiang Gao Peng xi Department of Biomedical engineering National Biomedical Imaging CenterCollege of Future TechnologyPeking UniversityBeijing 100871China Key Laboratory of Analytical science and Technology of Hebei Province College of Chemistry and Material ScienceHebei UniversityBaoding 071002China school of Life sciences Peking UniversityBeijing 100871China National Center for Protein sciences Peking UniversityBeijing 100871China

Mitochondria are crucial organelles closely associated with cellular metabolism and *** DNA(mtDNA)encodes a variety of transcripts and proteins essential for cellular ***,the interaction between the inner membrane(IM)and mtDNA remains elusive due to the limitations in spatiotemporal resolution offered by conventional microscopy and the absence of suitable in vivo probes specifically targeting the ***,we have developed a novel fluorescence probe called HBmito Crimson,characterized by exceptional photostability,fluorogenicity within lipid membranes,and low saturation *** successfully achieved over 500 frames of lowpower stimulated emission depletion microscopy(STED)imaging to visualize the IM dynamics,with a spatial resolution of 40 *** utilizing dual-color imaging of the IM and mtDNA,it has been uncovered that mtDNA tends to habitat at mitochondrial tips or branch points,exhibiting an overall spatially uniform ***,the dynamics of mitochondria are intricately associated with the positioning of mtDNA,and fusion consistently occurs in close proximity to mtDNA to minimize pressure during cristae *** healthy cells,>66%of the mitochondria are Class III(i.e.,mitochondria>5μm or with>12.cristae),while it dropped to<18%in *** dynamics,orchestrated by cristae remodeling,foster the even distribution of ***,in conditions of apoptosis and ferroptosis where the cristae structure is compromised,mtDNA distribution becomes *** findings,achieved with unprecedented spatiotemporal resolution,reveal the intricate interplay between cristae and mtDNA and provide insights into the driving forces behind mtDNA distribution.

关键词： metabolism saturation utilizing

Modeling and stabilization for a class of nonlinear networked control systems: A T-S fuzzy approach

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Progress in Natural science:materials International 2008年第8期18卷 1031-1037页

作者： xinchun Jiaa,*, Dawei Zhanga, Lihong Zheng a, Nanning Zheng b a school of Mathematics science, Shanxi {2., Taiyuan 030006, china b Institute of Artificial Intelligent and Robotics, xi’an jiaotong university, xi’an 710049, china school of Mathematics science Shanxi University Taiyuan 030006 China Institute of Artificial Intelligent and Robotics Xi’an Jiaotong University Xi’an 710049 China

The stabilization problem for a class of nonlinear networked control systems (NCSs) is investigated in this paper. A Takagi-Sugeno (T-S) fuzzy model is employed to represent the nonlinear controlled plant in the NCSs. Based on parallel distributed compensation (PDC) technique, a novel model of the nonlinear NCSs is established firstly in consideration of both network-induced delay and packet losses in transmission. Then a stability condition of the nonlinear NCSs is presented in terms of linear matrix inequalities (LMIs) by using the Lyapunov-Krasovskii functional method and the delay input approach. Furthermore, the control design of the nonlinear NCSs is developed by means of LMIs. Finally, a numerical example is given to demonstrate the effectiveness of the proposed method.

关键词： Nonlinear networked control systems Takagi–Sugeno (T-S) fuzzy systems Stabilization Packet losses Network-induced delay Linear matrix inequality (LMI)

Rectangle blocking matrices based unitary multistage Wiener reduced-rank joint detection algorithm for multiple input multiple output systems

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science china(Information sciences) 2010年第10期53卷 2116-2126页

作者： REN PinYi 1 , WANG Rui 2.& ZHANG ShiJiao 1 1 school of Electronic engineering,{2., xi’an 710049, china 2.xi’an Monitoring Station, The State Administration of Radio Film and Television, xi’an 710101, china 1. school of Electronic engineering Xi’an Jiaotong University Xi’an 710049 China2. Xi’an Monitoring Station The State Administration of Radio Film and Television Xi’an 710101 China

Traditional equalization algorithms for multiple input multiple output (MIMO) systems suffer from high complexity and low convergence rate. So an improved adaptive reduced-rank joint detection algorithm of multistage Wiener filter (MSWF) based on rectangle blocking matrices is proposed. The MSWF is implemented by the correlation subtraction algorithm (CSA) structure and is called unitary multistage Wiener filter (UMSWF). The new scheme adopts rectangle submatrix as blocking matrix, which is chosen from the square blocking matrix for UMSWF. The proposed algorithm can reduce the size of the observation data vectors step by step in the forward recursion decomposition of UMSWF. Thus, the computational complexity is reduced and the convergence rate is increased. Theoretical analysis and simulation results show that this improved adaptive reduced-rank joint detection algorithm of UMSWF based on rectangle blocking matrix has better performance such as lower complexity and faster convergence rate. In particular, simulations are conducted in the verticalBell Labs layered space-time (V-BLAST) system which adopts BPSK modulation, where 4 and 8 antennas are equipped at the transmitter and receiver, respectively. Compared with traditional equalization algorithm based on UMSWF, our new method can achieve the same BER performance at high SNR with only 0.5 times that of computational complexity.

关键词： multiple input multiple output (MIMO) systems unitary multistage Wiener filter (UMSWF) joint detection blocking matrix