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Dzyaloshinskii-Moriya Interaction in Spin 1/2 Antiferromagnetic Rings with Nearest Next Neighbor Coupling

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Chinese Physics Letters 2013年第4期30卷 189-191页

作者： li peng-fei CAO Hai-Jing ZHENG li Department of Mathematics and Physics Shanghai University of Electric PowerShanghai 200090

We numerically investigate the magnetoelastic(ME)instability in spin 1/2 antiferromagnetic rings with nearest-next neighbor(NNN)coupling J_(2)and Dzyaloshinskii–Moriya(DM)interaction D_(z).It is found that,for a given Dz,there exists a critical J_(2)^(c).As J_(2)=J_(2)^(c),the ME instability is irrelative to the DM interaction and NNN *** results may come from the competition between the DM interaction and NNN *** DM interaction does not affect the critical behavior at the point of J_(2)=0.5,at which the systems always locate in the dimerized state.

关键词： state. interaction critical

Nonchaoticity of Ordinary Differential Equations Describing Autonomous Transcriptional Regulatory Circuits

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Communications in Theoretical Physics 2008年第6期49卷 1639-1642页

作者： li peng-fei HU Gang CHEN Run-Sheng Department of Physics Beijing Normal University Beijing 100875 China Beijing-Hong Kong-Singapore Joint Center of Nonlinear and Complex Systems Beijing Normal University Branch Beijing 100875 China Bioinformatics Laboratory Institute of Biophysics the Chinese Academy of Sciences Beijing 100101 China

Gene transcriptional regulation （TR） processes are often described by coupled nonlinear ordinary differential equations （ODEs）. When the dimension of TR circuits is high （e.g. n≥3） the motions of the corresponding ODEs may, very probably, show self-sustained oscillations and chaos. On the other hand, chaoticity may be harmful for the normal biological functions of TR processes. In this letter we numerically study the dynamics of 3-gene TR ODEs in great detail, and investigate many 4-, 5-, and lO-gene TR systems by randomly choosing figures and parameters in the conventionally accepted ranges. And we find that oscillations are very seldom and no chaotic motion is observed, even if the dimension of systems is sufficiently high （n≥3）. It is argued that the observation of nonchaoticity of these ODEs agrees with normal functions of actual TR processes.

关键词： transcriptional regulatory circuit periodic oscillation nonchaoticity

Sensitive and Rapid Quantification of Felodipine by High-performance liquid Chromatography-tandem Mass Spectrometry(HPLC-MS/MS) and Its Pharmacokinetics in Healthy Chinese Volunteers

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Chemical Research in Chinese Universities 2006年第4期22卷 479-483页

作者： li Yan-yan YIN Yi-zi SUN Zhi-hui li Xin HU li-gang li peng-fei ZHONG Da-fang The First Hospital Jilin University Changchun 130021 P.R. China Research Center for Drug Metabolism Jilin University Changchun 130021 P. R. China

To investigate the pharmacokinetics of felodipine in the plasma of healthy Chinese volunteers, 30 healthy volunteers received a single oral dose of 5 mg of extended release felodipine tablets. The felodipine was extracted from the matrix with a liquid-liquid extract procedure and analyzed by high-performance liquid chromatography-tandem mass spectrometry in the multiple reaction monitoring（MRM） mode using an electrospray ion source with positive ion detection. The method was validated over a felodipine concentration range of 0. 05-10.00 ng/mL in human plasma. Its main pharmacokinetic parameters values were： ρmax = （ 1.67 ± 0. 84 ） ng/mL, occurring at （ 3.93 3± 2. 49 ） h; the plasma elimination half-life：（23. 08 3± 9. 48） h and the area under the plasma concentration versus time curve：（29. 94 ± 14. 39） ng · h/mL. The validation results demonstrated that this method showed a satisfactory precision and accuracy across the calibration range. The procedure involved minimal drug administration, sample preparation, and a 2. 5-min chromatographic run time. It was well suited to clinical studies of the drug involving large numbers of samples.

关键词： Felodipine liquid chromatography-tandem massspectrometry Pharmacokinetics

Medical Image Compression by Applying 3D DWT in PACS

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Wuhan University Journal of Natural Sciences 1999年第3期4卷 313-318页

作者： Wang Si-xian li fei-peng Zeng Fa-long liao Meng-yang li Hui Wuhan Univ Wuhan China

The process of image compression in a practical Picture Archiving and Communication System (PACS) was discussed with detail. To fully reduce the inter-slice correlation existing in the volumetric image sets generated by CT and MR, 3D Discrete Wavelet Transformation (DWT) was introduced in our application. Instead of using a fixed quantizer of lossless low frequency and distinct loss of high frequency, an adaptive quantizer was devised taking MSE as the performance index. In the low frequency subband, DPCM was replaced withS+P transform to facilitate coding computation. Compared with JPEG or 2D DWT, our method is 20%–50% more efficient. Furthermore, preliminary tests showed that 33 dB may be the maximal distortion threshold for CT images.

关键词： PACS 3D DWT S+P transformation optimal bit allocation maximal distortion threshold

Fate of fertilizer nitrogen and residual nitrogen in paddy soil in Northeast China

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Journal of Integrative Agriculture 2023年第11期22卷 3535-3548页

作者： BI Shi-ting LUO Xiang-yu ZHANG Chen li peng-fei YU Cai-lian liU Zhi-lei peng Xian-long College of Agricultural Resources and Environmental Sciences Northeast Agricultural UniversityHarbin 150030P.R.China Key Laboratory of Germplasm Enhancement Physiology and Ecology of Food Crops in Cold Region of Ministry of EducationNortheast Agricultural UniversityHarbin 150030P.R.China The School of Material Science and Chemical Engineering Harbin University of Science and TechnologyHarbin 150080P.R.China

The relationship between the fate of nitrogen (N) fertilizer and the N application rate in paddy fields in Northeast China is unclear,as is the fate of residual *** clarify these issues,paddy field and15N microplot experiments were carried out in 2017 and 2018,with N applications at five levels:0,75,105,135 and 165 kg N ha–1(N0,N75,N105,N135 and N165,respectively).15N-labeled urea was applied to the microplots in 2017,and the same amount of unlabeled urea was applied in *** (NH3) volatilization,leaching,surface runoff,rice yield,the N contents and15N abundances of both plants and soil were *** results indicated a linear platform model for rice yield and the application rate of N fertilizer,and the optimal rate was 135 kg N ha–1.N uptake increased with an increasing N rate,and the recovery efficiency of applied N (REN) values of the difference subtraction method were 45.23 and 56.98%on average in 2017and 2018,*** RENwas the highest at the N rate of 135 kg ha–1in 2017 and it was insignificantly affected by the N application rate in 2018,while the agronomic efficiency of applied N (AEN) and physiological efficiency of applied N (PEN) decreased significantly when excessive N was applied.N loss through NH3volatilization,leaching and surface runoff was low in the paddy fields in Northeast ***3volatilization accounted for 0.81 and 2.99%of the total N application in 2017 and 2018,*** average,the leaching and surface runoff rates were 4.45% and less than 1.05%,respectively,but the apparent denitrification loss was approximately 42.63%.The residual N fertilizer in the soil layer (0–40 cm) was 18.37–31.81 kg N ha–1in 2017,and the residual rate was 19.28–24.50%.Residual15N from fertilizer in the soil increased significantly with increasing N fertilizer,which was mainly concentrated in the 0–10 cm soil layer,accounting for 58.45–83.54% of the total residual N,and decreased with increasing *** the ratio of residual N in the

关键词： fate of N fertilizer NH_(3) volatilization leaching surface runoff residual nitrogen yield

Observations of Freak Waves in Random Wave Field in 2D Experimental Wave Flume

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China Ocean Engineering 2013年第5期27卷 659-670页

作者：李金宣李鹏飞柳淑学 State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology

Long time series of wave field are experimentally simulated by JONSWAP spectra with random phases in a 2D wave flume. Statistic properties of wave surface, such as significant wave height, skewness and kurtosis, are analyzed, and the freak wave occurrence probability and its relations with Benjamin-feir index （BFI） are also investigated. The results show that the skewness and the kurtosis are significantly dependent on the wave steepness, and the kurtosis increases along the flume when BFI is large. The freak waves are observed in random wave groups. They occur more frequently than expected, especially for the wave groups with large BFI.

关键词： freak waves Benjamin-feir instability random wave groups

Energy-effi cient MAC protocols for Wireless Sensor Networks

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信息通信技术 2009年第3期3卷 32-36页

作者： li Deliang peng fei Beihang University Beijing 100083

Designing energy-efficient Medium Access Control (MAC) protocols has a significant influence on the energy performance of wireless sensor network (WSN). In this paper we present a survey of the recent typical MAC protocols regarding energy effi ciency for WSN. According to channel access policies, we classify these protocols into four categories:contention-based, TDMA-based, hybrid, and cross layer protocols, in which the advantages and disadvantages in each class of MAC protocols are discussed. Finally, we point out open research issues that need to carry on to achieve high energy efficiency for the design of MAC protocols in WSN.

关键词：无线传感器网络通信技术 MAC协议介质访问控制

Command Filter Backstepping Control with Error Compensation for Flexible-Joint Manipulator 32

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Command Filter Backstepping Control with Error Compensation ...

Anti-tumor and Phenotypic Regulation Effect of Matrine on Dendritic Cells through Regulating TLRs Pathway

第32届中国控制与决策会议

作者： lin Meng-hao Zhang Lei Zhang Yin-he li peng-fei Wang Xiao-hua School of electronic and information Xian Polytechnic University

ISBN: (数字)9781728158556

ISBN: (纸本)9781728158556;9781728158563

This paper presents a modified position tracking control strategy using command filtering backstepping for the flexible-joint ***,the second-order command filter is adopted in the backstepping procedure to derive the virtual control function and its *** problem of "explosion of complexity" caused by the calculation of the partial derivatives of virtual control inputs is ***,to reduce the filtering error caused by adopting the command filter,the filtering error compensation is designed,and the stability of the tracking error closed-loop system is verified based on Lyapunov stability ***,simulation results on single-link flexible-joint manipulator show that the tracking accuracy is increased by about 12.8%,which indicate the position tracking accuracy is guaranteed by the proposed control method.

关键词： Flexible-Joint manipulator Backstepping Control Command Filter Filtering Error Compensation

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Chinese Journal of Integrative Medicine 2021年第7期27卷 520-526页

作者： WANG Jing-kang ZHAO Bao-sheng WANG Min liU Chen-yue li Ya-qi MA Quan-tao li peng-fei WANG Tie-shan WANG Chun-guo ZHOU Yong-ming School of Chinese Materia Medica Beijing University of Chinese MedicineBeijing100029China Beijing Research Institute of Chinese Medicine Beijing University of Chinese MedicineBeijing100029China School of Traditional Chinese Medicine Beijing University of Chinese MedicineBeijing100029China Department of Oncology Guang'anmen HospitalChina Academy of Chinese Medical SciencesBeijing100053China

Objective To investigate the effects of matrine on antigen presentation of dendritic cells(DCs),and to explore the pharmacological mechanism of matrine on anti-tumor *** Different concentrations(0,1,2,4,8 and 16µg/mL)of matrine were co-cultured with DCs,the harvested DCs were co-cultured with antigens of Lewis lung cancer(LLC)cells,and then DCs and T cells were co-cultured to produce DCs-activated killer(DAK)cells,which have significant tumor-killing *** expression of cytokines,mRNA and protein of toll-like receptors(TLRs)in DCs were detected by enzyme linked immunosobent assay,polymerase chain reaction and Western blot,*** the killing effect of DAK were measured by MTT *** Matrine significantly increased the mRNA expression of TLR7,TLR8,myeloid differentiation factor 88(MyD88),tumor necrosis factor receptor-associated factor 6(TRAF-6)and IκB kinase(IKK),as well as the protein expression of TLR7 and TLR8,and up-regulated the levels of interleukin-12(IL-12),IL-6 and tumor necrosis factor-α(TNF-α),meanwhile,it also increased the expressions of MHC-II,CD54,CD80 and CD86 in ***-activated effector T cells had significant tumor-killing *** the concentration of matrine was more than 4µg/mL,all indices had significant difference(P<0.01 or P<0.05).Conclusion Matrine plays an anti-tumor role by regulating TLRs signal transduction pathway,promoting the secretion of inflammatory cytokines and enhancing immune function.

关键词： matrine Chinese medicine dendritic cells tumors toll-like receptors inflammatory cytokines