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Finite Element Investigation of Flow Field Below Asymmetric Drill Bits for Reverse Circulation in Drilling Tight Oil and Gas Reservoirs

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Computer Modeling in Engineering & Sciences 2019年第10期121卷 105-122页

作者： Yi Luo Erxiu Shi yin feng Boyun Guo Liehui Zhang State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengduChina University of Louisiana at Lafayette LafayetteLAUSA.

Development of unconventional tight oil and gas reservoirs such as shale pays presents a huge challenge to the petroleum industry due to the naturally low permeability of shale formations and thus low productivity of oil and gas *** formations are also vulnerable to the contamination of the water in the drilling and completion fluids,which further reduces reservoir *** gas-drilling(drilling with gas)has been used to address the issue,several problems such as formation water influx,wellbore collapse,excessive gas volume requirement and hole cleaning in horizontal drilling,still hinder its application.A new technique called gas-lift drilling has recently been proposed to solve these problems,but the optimal design of drilling operation requires a thorough investigation of fluid flow field below the asymmetric drill bits for evaluating the fluid power needed to clean the bottom *** an investigation is conducted in this work based on the Finite Element Method(FEM)implemented in an open source computational framework,*** and flow velocity fields were computed for three designs of drill bit face characterized by radial bit blades and one eccentric orifice of *** of the designs is found superior over the other two because it generates relatively uniform flow velocities between blades and provides a balanced fluid power needed to clean all the bit teeth on each bit *** quantify the capability of borehole cleanup presented by three drill bit designs,the energy per unit volume is calculated in each region of drill bit and compared with the required value suggested by the *** addition,the developed FEM model under FEniCS framework provides engineers an accurate tool for optimizing drill bit design for efficiently gas-lift drilling unconventional tight oil and gas reservoirs.

关键词： Gas-lift drilling reverse circulation unconventional reservoirs bit design.

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Synthesis and Crystal Structure of 4-Azido-2,2,6,6-Tetramethylpiperidine-1-oxyl Free Radical

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Chinese Journal of Structural Chemistry 2006年第2期25卷 127-130页

作者： ZHOU Bao-Han CHEN Yun-feng yin Guo-Dong WU An-Xin Key Laboratory of Pesticide and Chemical Biology Ministry of Education College of Chemistry Central China Normal University Wuhan 430079 China

The title compound 4-azido-2,2,6,6-tetramethylpiperidine-l-oxyl （C9H17N4O, Mr = 197.27） has been synthesized and its structure was determined by single-crystal X-ray diffraction. The crystal belongs to triclinic, space group P1^- with a = 5.8464（12）, b = 8.2476（17）, c = 11.954（2） A°, a = 101.973（4）, β = 97.186（3）, γ, = 100.232（3）°, V = 546.98（19） ,A°^3, Z = 2, Dc= 1.198 g/cm^3, μ（MoKa） = 0.082 mm^-1, F（000） = 214, R = 0.0495 and wR = 0.1355 for 1677 observed reflections with I 〉 2σ（I）. X-ray analysis reveals that the six-membered ring adopts a chair conformation and the bond length of N（1）-O（1） is 1.2838（19）A°.

关键词： crystal structure nitroxide radical synthesis

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Temporal changes in the spinal cord transcriptome after peripheral nerve injury

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Neural Regeneration Research 2020年第7期15卷 1360-1367页

作者： Jian Weng Dong-Dong Li Bao-Guo Jiang Xiao-feng yin Department of Orthopedics and Trauma Peking University People's HospitalBeijingChina Department of Bone&Joint Surgery Peking University Shenzhen HospitalShenzhenGuangdong ProvinceChina Department of Surgery the 517th Hospital of the People's Liberation ArmyXinzhouShanxi ProvinceChina

Peripheral nerve injury may trigger changes in mRNA levels in the spinal *** key mRNAs is important for improving repair after nerve *** study aimed to investigate changes in mRNAs in the spinal cord following sciatic nerve injury by transcriptomic *** left sciatic nerve denervation model was established in C57 BL/6 *** left L4–6 spinal cord segment was obtained at 0,1,2,4 and 8 weeks after severing the sciatic *** expression profiles were generated by RNA *** sequencing results of spinal cord mRNA at 1,2,4,and 8 weeks after severing the sciatic nerve were compared with those at 0 weeks by bioinformatic *** identified 1915 differentially expressed mRNAs in the spinal cord,of which 4,1909,and 2 were differentially expressed at 1,4,and 8 weeks after sciatic nerve injury,*** results indicated that the number of differentially expressed mRNAs in the spinal cord was highest at 4 weeks after sciatic nerve *** mRNAs were associated with the cellular response to lipid,ATP metabolism,energy coupled proton transmembrane transport,nuclear transcription factor complex,vacuolar proton-transporting V-type ATPase complex,inner mitochondrial membrane protein complex,tau protein binding,NADH dehydrogenase activity and hydrogen ion transmembrane transporter *** these mRNAs,Sgk1,Neurturin and Gpnmb took part in cell growth and *** analysis showed that these mRNAs were mainly involved in aldosterone-regulated sodium reabsorption,oxidative phosphorylation and collecting duct acid *** assessment indicated that these mRNAs were associated with inflammation and cell morphology *** findings show that the number and type of spinal cord mRNAs involved in changes at different time points after peripheral nerve injury were *** number of differentially expressed mRNAs in the spinal cord was highest at 4 weeks after sciatic nerve *** results

关键词： deep sequencing expression profile gene therapy mRNAs nerve regeneration peripheral nerve injury RNA sequencing sciatic nerve injury spinal cord transcriptome

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Solidification behavior and elimination of undissolved Al_(2)CuMg phase during homogenization in Ce-modified Al–Zn–Mg–Cu alloy

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Rare Metals 2020年第11期39卷 1279-1287页

作者： Xin-Xiang Yu Jie Sun Zhu-Tie Li Han Dai Hong-Jie Fang Jun-feng Zhao Deng-feng yin School of Engineering Yantai Nanshan UniversityYantai 265713China Testing and Analysis Center Shandong Nanshan Aluminum Co.Ltd.Yantai 264006China

The solidification behavior and intermetallic phase evolution during homogenization annealing of an Al-Zn-Mg-Cu alloy with 0.12 wt%Ce addition were *** residual Al_(2)CuMg phase is completely dissolved after homogenization and is replaced by a large number of dispersed micro/nanoscaled AlCuCe enrichment phases within Al *** change occurs because of the formation of a large number of finer lamellar eutectic network structures which are more easily dissolved into Al matrix during the homogenization *** addition,the trapping of Cu atoms in the stable AlCuCe phase also prevents the formation of Al_(2)CuMg phase,leading to the complete dissolution of Al_(2)CuMg phase in the Al-Zn-MgCu *** grain refinement behavior in Al alloy with Ce addition is similar to that in alloys with the addition of Sc,because of the formation of primary Ce-enriched Al_(11)Ce_(3)phase as the nucleation agent ofα(Al)during solidification.

关键词： Al–Zn–Mg–Cu alloy Al_(2)CuMg phase Homogenization Grain refinement

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Study on the Method of Soil Productivity Assessment in Black Soil Region of Northeast China

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Agricultural Sciences in China 2009年第4期8卷 472-481页

作者： DUAN Xing-wu XIE Yun feng Yan-jie yin Shui-qing State Key Laboratory of Earth Surface Processes and Resource Ecology School of Geography Beijing Normal University Beijing 100875P.R. China

The objective of this paper is to investigate a simple and practical method for soil productivity assessment in the black soil region of Northeast China. Firstly, eight kinds of physicochemical properties for each of 120 soil samples collected from 25 black soil profiles were analyzed using cluster and correlation analysis. Subsequently, parameter indices were calculated using physicochemical properties. Finally, a modified productivity index （MPI） model were developed and validated. The results showed that the suitable parameters for soil productivity assessment in black soil region of Northeast China were soil available water, soil pH, clay content, and organic matter content. Compared with original productivity index （PI） model, MPI model added clay content and organic matter content in parameters while omitted bulk density. Simulation results of original PI model and MPI model were compared using crop yield of land block where investigated soil profiles were located. MPI model was proven to perform better with a higher significant correlation with maize yield. The correlation equation between MPI and yield was： Y= 3.2002Ln（MP/）＋ 10.056, R^2 = 0.7564. The results showed that MPI model was an effective and practical method to assess soil productivity in the research area.

关键词： PI MPI soil productivity black soil region of Northeast China

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Zinc bis-Schiff base complexes： Synthesis, structure, and application in ring-opening polymerization of rac-lactide

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Chinese Chemical Letters 2016年第11期27卷 1649-1654页

作者： Zhong-Ran Dai Chang-feng yin Cheng Wang Jin-Cai Wu State Key Laboratory of Applied Organic Chemistry Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province College of Chemistry and Chemical Engineering Lanzhou 730000 China The Second Affiliated Hospital of Lanzhou University Lanzhou 730000 China

A series of bis-ligated zinc complexes supported by Schitt base ligands were successfully synthesized and characterized by 1 H, 13C NMR, elemental analysis, and X-ray crystallography. These zinc complexes can be used as catalysts for the polymerization of rac-lactide in solution as well as in molten lactide. The results show that all catalysts exhibited high catalytic activity and obtained moderate heterotactic PLAs with the expected molecular weight. Complex 1 can catalyze the polymerization of rac-lactide under controllable conditions with living and immortal character in toluene solution. In addition, the steric hindrance and electronic effects has a great influence on the catalytic activity and selectivity of catalysts.

关键词： Rac-lactide Catalyst Zinc complex Ring-opening polymerization

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MicroRNA is a potential target for therapies to improve the physiological function of skeletal muscle after trauma

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Neural Regeneration Research 2022年第7期17卷 1617-1622页

作者： Xin-Yi Gu Bo Jin Zhi-Dan Qi Xiao-feng yin Department of Orthopedics and Traumatology Peking University People’s HospitalBeijingChina Key Laboratory of Trauma and Neural Regeneration(Peking University) BeijingChina Department of Orthopedics The First Affiliated Hospital of Nanjing Medical UniversityJiangsu Province HospitalNanjingJiangsu ProvinceChina

MicroRNAs can regulate the function of ion channels in many *** on our previous study we propose that miR-142a-39,which is highly expressed in denervated skeletal muscle,might affect cell excitability through similar *** this study,we overexpressed or knocked down miR-142a-3p in C2C12 cells using a lentivirus *** 7 days of differentiation culture,whole-cell currents were *** results showed that overexpression of miR-142a-3p reduced the cell membrane capacitance,increased potassium current density and decreased calcium current *** of miR-142a-3p reduced sodium ion channel current *** results showed that change in miR-142a-3p expression affected the ion channel currents in C2C12 cells,suggesting its possible roles in muscle cell *** study was approved by the Animal Ethics Committee of Peking University in July 2020(approval ***2017128).

关键词： C2C12 denervation ion channels microRNA miR-142a-3p muscle patch clamp potassium sodium whole-cell currents

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Primary Frequency Control Ability Evaluation of Valve Opening in Thermal Power Units Based on Artificial Neural Network

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Journal of Thermal Science 2020年第3期29卷 576-586页

作者： LIAO Jinlong LUO Zhihao yin feng CHEN Bo SHENG Deren LI Wei YU Zitao Institute of Thermal Science and Power Systems Zhejiang UniversityHangzhou 310027China Electric Power Research Institute of State Grid Zhejiang Electric Power Co.Ltd Hangzhou 310027China

With the development of new energy,the primary frequency control(PFC)is becoming more and more important and *** improve the reliability of the PFC,an evaluation method of primary frequency control ability(PFCA)was ***,based on the coupling model of the coordinated control system(CCS)and digital electro-hydraulic control system(DEH),principle and control mode of the PFC were introduced in *** simulation results showed that the PFC of the CCS and DEH was the most effective control ***,the analysis of the CCS model and variable condition revealed the internal relationship among main steam pressure,valve opening and *** term of this,the radial basis function(RBF)neural network was established to estimate the *** the simulation curves fit well with the actual curves,the accuracy of the coupling model was *** this basis,simulation data was produced by coupling model to verify the proposed evaluation *** low predication error of main steam pressure,power and the PFCA indicated that the method was *** addition,the actual data obtained from historical operation data were used to estimate the PFCA accurately,which was the strongest evidence for this method.

关键词： primary frequency control valve opening main steam pressure thermal power unit artificial neural network evaluation

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Troglitazone, a peroxisome proliferator-activated receptor γ ligand, induces growth inhibition and apoptosis of HepG2 human liver cancer cells

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World Journal of Gastroenterology 2008年第14期14卷 2168-2173页

作者： Yan-Ming Zhou yin-Hao Wen Xiao-Yan Kang Hai-Hua Qian Jia-Mei Yang Zheng-feng yin Department of Molecular Oncology Eastern Hepatobiliary Surgery Hospital Second Military Medical University Shanghai 200438 China

AIM: To examine the effect of troglitazone, a peroxisome proliferator-activated receptor γ (PPARγ) ligand, on the proliferation and apoptosis of human liver cancer cells. METHODS: Liver cancer cell line HepG2 was cultured and treated with troglitazone. Cell proliferation was detected by 3-(4-,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay; apoptosis was detected by flow cytometry and terminal deoxynucleotidyl transferase- mediated nick end labeling of DNA fragmentation sites (TUNEL) assay; and apoptosis-related protein was detected by immunocytochemistry and Western blotting. RESULTS: Troglitazone inhibited growth and induced apoptosis of HepG2 cells in a dose-dependent manner, and induced activation of caspase-3 expression. Troglitazone not only drove apoptosis-inhibiting factor survivin to translocate incompletely from the nucleus to the cytoplasm, but also inhibited expression of survivin, while it did not affect expression of apoptosis-promoting factor Bax. CONCLUSION: PPARγ ligands inhibit growth and induce apoptosis of liver cancer cells, and may have applications for the prevention and treatment of liver cancer.

关键词： Peroxisome proliferator-activated receptor γ Troglitazone Liver neoplasms Apoptosis

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China's Construction Land Expansion and Economic Growth:A Capital-output Ratio Based Analysis

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China & World Economy 2008年第6期16卷 46-62页

作者： Huizhong Li feng yin Jialun Li Professor Fudan University Shanghai China Agriculture Bank of China Shanghai China PhD Student Wharton School University of Pennsylvania Philadelphia USA

Since 2003, the Chinese Government has included land policy as an important component of macroeconomic policy. The present paper analyzes the impact of the expansion of construction land on economic growth in terms of the capital-output ratio. Using provincial panel data for China from 1999to 2005, we conclude that the excess expansion of China＇s construction land led to an increase in the capital-output ratio. Therefore, expanding construction land has made little contribution to economic growth. This paper argues that contractionary land policy does not deter high economic growth, and is a necessary condition for sustainable economic growth.

关键词： capital-output ratio construction land economic growth land policy

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