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Experimental study of the temporary plugging capability of diverters to block hydraulic fractures in high-temperature geothermal reservoirs

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Petroleum Science 2023年第6期20卷 3687-3699页

作者： Dao-Bing Wang hao Qin Yong-Liang Wang jian-Qiao Hu dong-Liang Sun Bo Yu School of Mechanical Engineering Beijing Institute of Petrochemical TechnologyBeijing102617China Jinan Branch China Petroleum and Chemical CorporationJinan250101ShandongChina School of Mechanics and Civil Engineering China University of Mining and Technology(Beijing)Beijing100083China LNM Institute of MechanicsChinese Academy of SciencesBeijing100190China

The effective plugging of artificial fractures is key to the success of temporary plugging and diverting fracturing technology,which is one of the most promising ways to improve the heat recovery efficiency of hot dry *** present,how temporary plugging agents plug artificial fractures under high temperature remains *** this paper,by establishing an improved experimental system for the evaluation of temporary plugging performance at high temperature,we clarified the effects of high temperature,injection rate,and fracture width on the pressure response and plugging efficiency of the *** results revealed that the temporary plugging process of artificial fractures in hot dry rock can be divided into four main stages:the initial stage of temporary plugging,the bridging stage of the particles,the plugging formation stage,and the high-pressure dense plugging *** the temperature increases,the distribution distance of the temporary plugging agent,the number of pressure fluctuations,and the time required for crack plugging ***,when the temperature increases by 100℃,the complete plugging time increases by 90.7%.

关键词： High temperature Diverter material Fracture plugging capability Hydraulic fracturing Experimental study

Deciphering fungal metabolon coupling tandem inverse-electrondemand Diels-Alder reaction and semipinacol rearrangement for the biosynthesis of spiro polycyclic alkaloids

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Science China Chemistry 2025年第01期 288-296页

作者： Shuai Liu Wen-Qiang Xu Ying-Tong Di Man-Cheng Tang Ding-Kang Chen Ming-Ming Cao Yao-Wen Chang Hong-Yu Tang Chun-Mao Yuan Jun-Bo Yang Zhi-Li Zuo Han Guo Zi-Fei Xu Ying Zeng Yun-dong Wu Xiao-jiang hao Key Laboratory of Phytochemistry and Natural Medicines (Chinese Academy of Sciences) Kunming Institute of Botany Chinese Academy of Sciences University of Chinese Academy of Sciences Lab of Computational Chemistry and Drug Design State Key Laboratory of Chemical Oncogenomics Peking University Shenzhen Graduate School Shenzhen Bay Laboratory State Key Laboratory of Microbial Metabolism School of Life Sciences & Biotechnology Shanghai Jiao Tong University State Key Laboratory of Functions and Applications of Medicinal Plants Guizhou Medical University Molecular Biology Experimental Center Germplasm Bank of Wild Species in Southwest China Kunming Institute of Botany Chinese Academy of Sciences Yunnan Key Laboratory for Wild Plant Resources Kunming Institute of Botany Chinese Academy of Sciences Research Unit of Chemical Biology of Natural Anti-Virus Products Chinese Academy of Medical Sciences

In the intricate process of natural product biosynthesis, a metabolon can enhance metabolic flux by associating sequential enzymes. A fungal metabolon, comprising of flavin-dependent monooxygenase Spe F and P450 monooxygenase Spe G, is identified in the biosynthesis of spiro polycyclic alkaloids(+)-notoamide B and its diastereomer(+)-versicolamide B. Using notoamide E as a substance, Spe F/Spe G metabolon can control the stereoselectivity of its 2,3-epoxidation, followed by hydrogen atom ion at C-17 to generate reactive epoxide tau-m A with dienyl iminium unit. Subsequently,(+)-notoamide B and(+)-versicolamide B are produced via tandem nonenzymatic inverse-electron-demand Diels-Alder reaction and semipinacol rearrangement. This provides the first example of metabolon in the biosynthesis of spiro-prenylated indole alkaloids.

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Performance Analysis of Relay Based NOMA Cooperative Transmission under Cognitive Radio Network

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Computers, Materials & Continua 2020年第4期63卷 197-212页

作者： Yinghua Zhang jian Liu Yunfeng Peng Yanfang dong Guozhong Sun hao Huang Changming Zhao School of Computer and Communication Engineering University of Science and Technology BeijingBeijing100083China Dawning Information Industry(Beijing)Co. Ltd.Beijing100083China Higon Austin R&D Center AustinTX 78746USA School of Computer Science Chengdu University of Information TechnologyChengdu610225China College of Computer Science Sichuan UniversityChengdu610041China

This paper proposes a hybrid spectrum accessing mechanism by using NOMA-based cooperative transmission and beam-forming *** this mechanism,the secondary user employs spectrum-sensing technology to detect the existence of the primary *** the primary user does not exist,the secondary source user directly transmits data to the destination *** the primary user exists,the secondary source user finds the optimal relay according to certain selection principle before transmitting data to the destination user through the chosen relay *** the signal receiving stage,the secondary user takes use of beam-forming technology to receive the signal from both the secondary source and the secondary relay *** the interference from the primary user is cancelled out in the ***,the outage probability for secondary user in the proposed mechanism is theoretically ***,the simulation results show that compared with the traditional mechanism,the proposed system model can not only guarantee the continuity of secondary transmission,but also significantly reduce the outage probability of secondary transmission.

关键词： Relay selection outage probability NOMA QoS signal-to-interference-plus-noise rate(SINR) beam-forming

Generation of Leydig-like cells:approaches,characterization,and challenges

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Asian Journal of Andrology 2022年第4期24卷 335-344页

作者： Zhao-Hui Li Jun-dong Lu Shi-Jun Li hao-Lin Chen Zhi-jian Su Guangdong Provincial Key Laboratory of Bioengineering Medicine Department of Cell BiologyJinan UniversityGuangzhou 510632China lnstitute of Life Sciences Wenzhou UniversityWenzhou 325035China Department of Gynecology and Obstetrics The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical UniversityWenzhou 325027China National Engineering Research Center of Genetic Medicine Jinan UniversityGuangzhou 510632China

Testosterone production by Leydig cells(LCs)plays a crucial role in male *** functional degeneration of LCs can cause testosterone deficiency,ultimately resulting in primary male *** of exogenous LCs with the ability to produce testosterone in response to the regulation of the hypothalamus-pituitary-gonad axis could be a promising alternative option to treat male primary *** studies have shown that it is possible to generate Leydig-like cells from stem cells by various *** addition,somatic cells,such as embryonic or adult fibroblasts,have also been successfully reprogrammed into Leydig-like *** this review,we summarized the recent advances in the generation of Leydig-like cells,with an emphasis on comparing the effectiveness and safety of different protocols used and the cells *** further analyzing the characteristics of Leydig-like cells generated from fibroblasts based on small signaling molecules and regulatory factors,we found that although the cells may produce testosterone,they are significantly different from real *** future in vivo applications,it is important that the steroidogenic cells generated be evaluated not only for their steroidogenic functions but also for their overall cell metabolic state by proteomics or transcriptomic tools.

关键词： fibroblasts hypogonadism Leydig-like cells reprogramming stem cells

Cyclic-Auto-Correlation Based Timing Estimation Algorithm for Time-Frequency Overlapping Multi-Carrier Signals

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Journal of Electronic Science and Technology 2020年第3期18卷 223-233页

作者： Xing Zhang jian-hao Hu National Key Laboratory of Science and Technology on Communications University of Electronic Science and Technology of ChinaChengdu 610054

In recent years,the time-frequency overlapping multi-carrier signal has been a novel and valuable topic in blind signal processing,especially in the non-cooperative receiving *** there is little related research in public published *** paper proposes two timing estimation algorithms,which are non-data-aided and based on the cyclic auto-correlation *** order to evaluate the performance of the proposed algorithms,the theoretical bound of the timing estimation is *** to the analyses and simulation results,the effectiveness of the proposed algorithms has been *** shows that MethodⅠhas better performance than MethodⅡ.However,MethodⅡdoes not need prior information,so it has a wider range of applications.

关键词： Cyclic auto-correlation orthogonal frequency division multiplexing(OFDM) time-frequency overlapping signal timing estimation

脂蛋白(a)浓度变化与急性冠脉综合征患者预后的关系

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岭南心血管病杂志 2012年第4期18卷 337-341,363页

作者：欧艳秋易师欣董豪坚余丹青周颖玲广东省医学科学院广东省人民医院广东省心血管病研究所广州510080

目的探讨血清脂蛋白(a)[lipoprotein(a),Lp(a)]浓度以及Lp(a)浓度的变化对经皮冠状动脉介入(percutaneouscoronary intervention,PCI)治疗完全血运重建后的急性冠脉综合征(acute coronary syndrome,ACS)患者预后的影响。方法选取240例因ACS行冠状动脉支架植入术并予常规药物治疗的患者,临床随访一年。检测基线及随访半年时Lp(a)浓度,并收集传统的心血管危险因素以及主要心血管事件(major adverse cardiac events,MACE)的资料。通过多因素Logistic回归的方法评价血清Lp(a)浓度的变化(基线水平至随访半年的变化)是否与ACS患者预后相关。结果基线血清Lp(a)浓度与冠状动脉Gensini评分呈正相关(r=0.142,P=0.027),与糖尿病的发生(r=-0.182,P=0.005)以及三酰甘油浓度(r=-0.156,P=0.016)呈负相关。在MACE发生的患者中,Lp(a)浓度平均升高了50 mg/L,而在非MACE患者中平均下降了40 mg/L。单因素Logistic回归分析发现基线Lp(a)浓度与MACE的发生无明显关系(OR=1.123,P=0.753),并筛选年龄(OR=1.03,P=0.060),Gensini评分(OR=1.010,P=0.015),原发性高血压(OR=1.696,P=0.069),糖尿病(OR=1.818,P=0.060)以及血清Lp(a)浓度变化的差值(OR=0.027,P=0.027)进入多因素Logistic逐步回归分析,发现Lp(a)浓度的变化(OR=3.119,95%CI=1.112～8.746,P=0.031)以及Gensini评分(OR=1.010,95%CI=1.002～1.018,P=0.016)可能是影响ACS预后的独立危险因素。结论基线血清Lp(a)浓度与ACS的预后无明显相关,与糖尿病的发生以及三酰甘油浓度呈负相关。在随访过程中,血清Lp(a)浓度的变化可能是ACS不良预后的独立危险因素。

关键词：冠状动脉疾病脂蛋白(a) 预后

Environmental Adaptive Control of a Snake-like Robot With Variable Stiffness Actuators

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IEEE/CAA Journal of Automatica Sinica 2020年第3期7卷 745-751页

作者： dong Zhang hao Yuan Zhengcai Cao IEEE College of Information Science and Technology Beijing University of Chemical TechnologyBeijing 100029China

This work investigates adaptive stiffness control and motion optimization of a snake-like robot with variable stiffness actuators. The robot can vary its stiffness by controlling magnetorheological fluid(MRF) around actuators. In order to improve the robot's physical stability in complex environments, this work proposes an adaptive stiffness control strategy. This strategy is also useful for the robot to avoid disturbing caused by emergency situations such as collisions. In addition, to obtain optimal stiffness and reduce energy consumption, both torques of actuators and stiffness of the MRF braker are considered and optimized by using an evolutionary optimization algorithm. Simulations and experiments are conducted to verify the proposed adaptive stiffness control and optimization methods for a variable stiffness snake-like robots.

关键词： Adaptive control snake-like robot variable stiffness

Phase Selection and Microstructure Evolution Dependance on Composition for Zr-Fe Eutectic Alloys

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Acta Metallurgica Sinica(English Letters) 2024年第10期37卷 1689-1702页

作者： dong-dong Zuo jian Chang Hai-Peng Wang School of Physical Science and Technology Northwestern Polytechnical UniversityXi’an710072China

The knowledge of the phase selection and microstructure evolution of Zr-Fe eutectic alloys is still poorly *** presumed eutectic alloy with a nominal composition of Zr76.0Fe24.0 was discovered to contain a significant proportion ofα-Zr ***,phase selection and microstructure evolution dependance on composition for Zr-Fe eutectic alloys was experimentally determined by using differential scanning calorimetry(DSC)and meticulous electron *** alloys,spanning the composition range of 73.5-74.7%Zr,were examined to investigate microstructure evolution and non-isothermal crystallization *** indicate that in alloys ranging from Zr_(73.5)Fe_(26.5) to Zr_(73.9)Fe_(26.1),the primary FeZr_(2) phase demonstrates preferential growth,followed by eutectic microstructure formation during liquid alloy *** volume fraction of FeZr_(2) dendrites decreases as the Zr content ***,in alloys ranging from Zr_(74.0)Fe_(26.0) to Zr_(74.7)Fe_(25.3),primaryβ-Zr dendrites preferentially grow,followed by a eutectic reaction in the remaining liquid *** content ofα-Zr dendrites reduces with decreasing Zr *** mentioned above,a critical composition range for phase selection is defined as Zr_(x)Fe100.0−x(73.9

关键词： Phase selection Thermal analysis Microstructure evolution Crystallization kinetic

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喷印金属微滴撞击粗糙表面的分子动力学模拟

原子与分子物理学报 2025年第4期42卷 73-80页

作者：苏仁健陈小勇游自浩桂林电子科技大学机电工程学院桂林541004 广西制造系统与先进制造技术重点实验室桂林541004

研究金属微滴撞击固体表面的行为对预测微滴形态和实现高精度的喷印制造具有重要的意义.然而,由于微纳尺度下金属微滴撞击实验的难以开展,目前涉及金属微滴撞击粗糙表面的形态变化和热毛细效应机理尚不清楚.本文采用分子动力学模拟研究... 详细信息

研究金属微滴撞击固体表面的行为对预测微滴形态和实现高精度的喷印制造具有重要的意义.然而,由于微纳尺度下金属微滴撞击实验的难以开展,目前涉及金属微滴撞击粗糙表面的形态变化和热毛细效应机理尚不清楚.本文采用分子动力学模拟研究了镓铟微滴撞击粗糙表面的动态行为,定量分析了撞击速度、粗糙结构和不同温度对微滴撞击行为的影响.结果表明:随着撞击速度的提高,微滴先后呈现沉积、弹跳和破碎飞溅三种模式,且微滴的最大铺展因子与韦伯数呈幂函数关系.此外,通过修饰基底粗糙结构发现,结构间距或高度的变化对微滴的弹跳行为存在不同的影响机制,可以有效促使或抑制微滴的弹跳行为.最后,分析得出随着温度的提高,微滴的铺展直径会变大,产生的黏性耗散也会增大.研究结果对金属微滴撞击行为的有效预测提供了理论基础.

关键词：金属微滴撞击粗糙基底分子动力学