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Capacity analysis for cognitive heterogeneous networks with ideal/non-ideal sensing

Tao HUANG, Ying-lei TENG, Meng-ting LIU, Jiang LIU

《信息与电子工程前沿（英文）》 2015年 第16卷 第1期   页码 1-11 doi: 10.1631/FITEE.1400129

摘要： Due to irregular deployment of small base stations (SBSs), the interference in cognitive heterogeneous networks (CHNs) becomes even more complex; in particular, the uncertainty of spectrum mobility aggravates the interference context. In this case, how to analyze system capacity to obtain a closed-form expression becomes a crucial problem. In this paper we employ stochastic methods to formulate the capacity of CHNs and achieve a closed-form expression. By using discrete-time Markov chains (DTMCs), the spectrum mobility with respect to the arrival and departure of macro base station (MBS) users is modeled. Then an integral method is proposed to derive the interference based on stochastic geometry (SG). Also, the effect of sensing accuracy on network capacity is discussed by concerning false-alarm and miss-detection events. Simulation results are illustrated to show that the proposed capacity analysis method for CHNs can approximate the conventional sum methods without rigorous requirement for channel station information (CSI). Therefore, it turns out to be a feasible and efficient way to capture the network capacity in CHNs.

关键词： Cognitive heterogeneous networks     Markov chain     Stochastic geometry     Homogeneous Poisson point process (HPPP)    

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施工导流工程风险的保险费用厘定方法研究

陈志鼎,胡志根

《中国工程科学》 2011年 第13卷 第4期   页码 106-112

摘要： ="text-align: justify;">在分析导流工程风险因素、综合风险率和工程保险期限的基础上，研究导流工程失效后淹没基坑造成损失的次数及其分布规律，提出导流系统失效后的总损失服从非齐次复合Poisson

关键词： 导流风险     工程保险     保险费     非齐次复合Poisson过程    

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多点协同传输机制下的多层无人机—地面异构网络覆盖性能分析 Research Article

王维昊,蒋逸凡,费泽松,郭婧

《信息与电子工程前沿（英文）》 2022年 第23卷 第1期   页码 61-72 doi: 10.1631/FITEE.2100310

摘要： 为满足第六代移动通信的泛在连接需求，无人机作为未来通信网络主要组成部分发挥着关键作用。频谱共享和视距链路传输造成的干扰是无人机通信的一个主要问题。近年来，为减少无人机—地面异构网络干扰，提出多点协同传输技术。本文提出一个三维多层无人机—地面异构网络，其中无人机作为空中基站部署于不同高度。利用随机几何理论，提出一个易于处理的数学框架评估这个异构网络的干扰统计特性和覆盖概率。数值结果表明多点协同传输机制能有效缓解网络中的干扰，尤其当基站密度较大时。此外，部署在更高的空中基站的系统参数是影响所提三维异构网络覆盖性能的主要因素。

关键词： 无人机；泊松点过程；多点协同；干扰统计特性；覆盖性能    

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Preparation and microstructure analysis of Fe-doped PbTiO ceramic

QIANG Liangsheng, MA Jing, CHU Jia, ZHANG Xiaohong

《化学科学与工程前沿（英文）》 2008年 第2卷 第2期   页码 140-144 doi: 10.1007/s11705-008-0021-4

摘要： Fe-doped PbTiO (PT) powder and bulk materials were prepared successfully by sol-gel technique and a subsequent sintering process using Fe (CH) as a dopant agent. The effects of pH and temperature on the Fe-doped PT system were investigated. Thermogravimetry/differential thermal analysis (TG/DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to analyze the composition and the microstructure of the PT ceramics. The results indicated that the thermal decomposition of xerogel included three stages: volatilization of adsorption water and organic composition, oxygenolysis of -butyl and acetate, and transformation of the crystalline phase. Well-stabilized collosol and gel could be obtained at 60°C and pH = 4.5. It was found that PbTiO, PbFeO, and TiO crystalline appeared in the Fe-doped PT system when the mass fraction of the dopant Fe was 0.03%. Furthermore, from STM analysis, it could be seen that the grain size of doped PT ceramics was homogeneous and about 1–2 ?m, and the pore of the PT ceramic was small. As a result, the PT ceramic had high tightness.

关键词： homogeneous     Thermogravimetry/differential thermal     tightness     oxygenolysis     sintering process    

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Effect of a less permeable stronger soil layer on the stability of non-homogeneous unsaturated slopes

Nabarun DEY, Aniruddha SENGUPTA

《结构与土木工程前沿（英文）》 2020年 第14卷 第6期   页码 1462-1475 doi: 10.1007/s11709-020-0674-8

摘要： Slope failure occurs due to an increase in the saturation level and a subsequent decrease in matric suction in unsaturated soil. This paper presents the results of a series of centrifuge experiments and numerical analyses on a 55° inclined unsaturated sandy slope with less permeable, stronger silty sand layer inclusion within it. It is observed that a less permeable, stronger silty sand layer in an otherwise homogeneous sandy soil slope hinders the infiltration of water. The water content of the slope just above the stronger layer increases significantly, compared to elsewhere. No shear band is found to initiate in a homogeneous sandy soil slope, whereas for a non-homogeneous slope, they initiate just above the less pervious, stronger layer. A discontinuity of the shear zone is also observed for the case of a non-homogeneous soil slope. The factor of safety of a non-homogeneous, unsaturated soil slope decreases because of the less permeable, stronger layer. It decreases significantly if this less permeable, stronger soil layer is located near the toe of the slope.

关键词： non-homogeneous slope     stronger soil layer     factor of safety     centrifuge model test     unsaturated soils    

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Control of homogeneous charge compression ignition combustion in a two-cylinder gasoline direct injection

WANG Zhi, WANG Jianxin, SHUAI Shijin, MA Qingjun, TIAN Guohong

《能源前沿（英文）》 2007年 第1卷 第3期   页码 311-315 doi: 10.1007/s11708-007-0045-3

摘要： Homogeneous charge compression ignition (HCCI) has challenges in ignition timing control, combustion rate control, and operating range extension. In this paper, HCCI combustion was studied in a two-cylinder gasoline direct injection (GDI) engine with negative valve overlap (NVO). A two-stage gasoline direct injection strategy combined with negative valve overlap was used to control mixture formation and combustion. The gasoline engine could be operated in HCCI combustion mode at a speed range of 800–2 200 r/min and load, indicated mean effective pressure (IMEP) range of 0.1–0.53 MPa. The engine fuel consumption is below 240 g/(kW

关键词： Homogeneous     control     combustion     consumption     extension    

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Anaerobic treatment of wastewater containing methanol in up-flow anaerobic sludge bed (UASB) reactor

LIN Yishan, HE Yanling, MENG Zhuo, YANG Shucheng

《环境科学与工程前沿（英文）》 2008年 第2卷 第2期   页码 241-246 doi: 10.1007/s11783-008-0040-x

摘要： The direct conversion of methanol into methane is the main process in anaerobic treatment of methanol containing wastewater. However, acetic acid can also be produced from methanol theoretically, which may probably result in an abrupt pH drop and deteriorate the anaerobic process. Therefore, it is interesting to know what would really happen in an anaerobic reactor treating methanol wastewater. In this study, an up-flow anaerobic sludge bed (UASB) reactor treating methanol wastewater was operated. The chemical oxygen demand (COD), acetic acid and pH of the effluent were monitored at different loadings and influent alkalinity. The results showed that the anaerobic reactor could be operated steadily at as low as 119 mg/L of influent alkalinity and high organic loading rate with no obvious pH drops. Volatile fatty acids accumulation was not observed even at strong shock loadings. The microorganisms in the sludge at the end of the test became homogeneous in morphology, which were mainly spherical or spheroidal in shape.

关键词： homogeneous     spherical     influent alkalinity     process     anaerobic treatment    

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Liquid discharge plasma for fast biomass liquefaction at mild conditions: The effects of homogeneous

Sen Wang, Shiyun Liu, Danhua Mei, Rusen Zhou, Congcong Jiang, Xianhui Zhang, Zhi Fang, Kostya (Ken) Ostrikov

《化学科学与工程前沿（英文）》 2020年 第14卷 第5期   页码 763-771 doi: 10.1007/s11705-019-1896-y

摘要： Non-thermal plasma exhibits unique advantages in biomass conversion for the sustainable production of higher-value energy carriers. Different homogeneous catalysts are usually required for plasma-enabled biomass liquefaction to achieve time-and energy-efficient conversions. However, the effects of such catalysts on the plasma-assisted liquefaction process and of the plasma on those catalysts have not been thoroughly studied. In this study, an electrical discharge plasma is employed to promote the direct liquefaction of sawdust in a mixture of polyethylene glycol 200 and glycerol. Three commonly used chemicals, sulfuric acid, nitric acid and sodium -toluene sulfate, were selected as catalysts. The effects of the type of catalyst and concentration on the liquefaction yield were examined; further, the roles of the catalysts in the plasma liquefaction process have been discussed. The results showed that the liquefaction yield attains a value of 90% within 5 min when 1% sulfuric acid was employed as the catalyst. Compared with the other catalysts, sulfuric acid presents the highest efficiency for the liquefaction of sawdust. It was observed that hydrogen ions from the catalyst were primarily responsible for the significant thermal effects on the liquefaction system and the generation of large quantities of active species; these effects directly contributed to a higher efficacy of the plasma-enabled liquefaction process.

关键词： discharge plasma     biomass liquefaction     catalyst     homogeneous catalysts    

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Effects of compression ratio on the combustion characteristics of a homogeneous charge compression ignition

SONG Ruizhi, ZHOU Longbao, LIU Shenghua, LI Wei, HU Tiegang

《能源前沿（英文）》 2007年 第1卷 第4期   页码 463-467 doi: 10.1007/s11708-007-0068-0

摘要： The effects of homogeneous charge compression ignition (HCCI) engine compression ratio on its combustion characteristics were studied experimentally on a modified TY1100 single cylinder engine fueled with dimethyl ether. The resul

关键词： homogeneous     cylinder     combustion     compression     dimethyl    

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Reactive adsorption desulfurization over a Ni/ZnO adsorbent prepared by homogeneous precipitation

Aihua KONG, Yanyu WEI, Yonghong LI

《化学科学与工程前沿（英文）》 2013年 第7卷 第2期   页码 170-176 doi: 10.1007/s11705-013-1322-9

摘要： A high-performance Ni/ZnO adsorbent was prepared by homogeneous precipitation using urea hydrolysis and characterized by N adsorption-desorption, X-ray diffraction (XRD), and scanning electron microscope (SEM). The adsorbent was applied to the deep desulfurization of gasoline and showed a high breakthrough sulfur capacity and a remarkably high volume hourly space velocity. The effects of coexisting olefins in gasoline as well as adsorptive conditions on the adsorptive performance were examined. It was found that olefins in gasoline had a slightly inhibiting effect on the desulfurization performance of the adsorbent. The optimum conditions were 673 K, 1.0 Mpa with a volume hourly space velocity of 60 h . Under the optimum conditions, ultralow sulfur gasoline could be produced and the breakthrough sulfur capacity of the adsorbent was 360 mg-s/g-sorb for the model gasoline.

关键词： nickel     reactive adsorption     desulfurization     thiophene    

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双层辉光离子渗金属技术特点

高原,徐晋勇,高清,安晋平,徐重

《中国工程科学》 2008年 第10卷 第2期   页码 26-30

摘要：

分析了双层辉光技术的特点，指出该技术在材料表面合金化方面，是一项适合于高熔点金属 表面合金化和采用高熔点金属对铁基或某些熔点较高的有色金属材料进行表面合金化的工艺技术.

关键词： 双层辉光离子渗金属技术     高熔点金属     空心阴极效应     阴极溅射     扩散    

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轴向零泊松比结构心血管支架的设计、3D打印与表征 Article

王程锦, 张磊, 方永聪, 孙伟

《工程（英文）》 2021年 第7卷 第7期   页码 979-990 doi: 10.1016/j.eng.2020.02.013

摘要：

药物洗脱支架固有的缺陷促进了生物可吸收心血管支架的研究与发展。近年来，增材制造技术（也称3D打印技术）在医疗器械领域得到了广泛的应用。本文提出了一种新型的微螺杆挤出式3D打印系统，并利用该系统制备了一种具有零泊松比（ZPR）结构的支架。首先进行了初步的单丝挤出试验来研究合适的制造参数；随后，制备了具有不同几何结构的3D打印支架，并通过扫描电子显微镜（SEM）观察分析支架表面形貌；最后，对不同参数的3D打印支架进行了力学性能评价和初步的生物学评价。总之，基于微螺杆挤出式3D打印系统具有制备个性化支架的潜力。

关键词： 增材制造     3D打印     螺杆挤出     心血管支架     零泊松比    

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Two-sided ultrasonic surface rolling process of aeroengine blades based on on-machine noncontact measurement

Shulei YAO, Xian CAO, Shuang LIU, Kaiming ZHANG, Xiancheng ZHANG, Congyang GONG, Chengcheng ZHANG

《机械工程前沿（英文）》 2020年 第15卷 第2期   页码 240-255 doi: 10.1007/s11465-019-0581-7

摘要： As crucial parts of an aeroengine, blades are vulnerable to damage from long-term operation in harsh environments. The ultrasonic surface rolling process (USRP) is a novel surface treatment technique that can highly improve the mechanical behavior of blades. During secondary machining, the nominal blade model cannot be used for secondary machining path generation due to the deviation between the actual and nominal blades. The clamping error of the blade also affects the precision of secondary machining. This study presents a two-sided USRP (TS-USRP) machining for aeroengine blades on the basis of on-machine noncontact measurement. First, a TS-USRP machining system for blade is developed. Second, a 3D scanning system is used to obtain the point cloud of the blade, and a series of point cloud processing steps is performed. A local point cloud automatic extraction algorithm is introduced to extract the point cloud of the strengthened region of the blade. Then, the tool path is designed on the basis of the extracted point cloud. Finally, an experiment is conducted on an actual blade, with results showing that the proposed method is effective and efficient.

关键词： aeroengine blades     on-machine noncontact measurement     point cloud processing     path planning     surface strengthening    

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STRENGTHENING NON-POINT SOURCE POLLUTION CONTROL TO PROMOTE AGRICULTURAL GREEN DEVELOPMENT

《农业科学与工程前沿（英文）》 2023年 第10卷 第4期   页码 503-509 doi: 10.15302/J-FASE-2023528

摘要：

STRENGTHENING NON-POINT SOURCE POLLUTION CONTROL TO PROMOTE AGRICULTURAL GREEN DEVELOPMENT

关键词： GREEN     AGRICULTURAL     PROMOTE     POLLUTION     SOURCE     DEVELOPMENT     POINT     STRENGTHENING     CONTROL    

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Trajectory planning of mobile robots using indirect solution of optimal control method in generalized point-to-point

M. NAZEMIZADEH, H. N. RAHIMI, K. AMINI KHOIY

《机械工程前沿（英文）》 2012年 第7卷 第1期   页码 23-28 doi: 10.1007/s11465-012-0304-9

摘要：

This paper presents an optimal control strategy for optimal trajectory planning of mobile robots by considering nonlinear dynamic model and nonholonomic constraints of the system. The nonholonomic constraints of the system are introduced by a nonintegrable set of differential equations which represent kinematic restriction on the motion. The Lagrange’s principle is employed to derive the nonlinear equations of the system. Then, the optimal path planning of the mobile robot is formulated as an optimal control problem. To set up the problem, the nonlinear equations of the system are assumed as constraints, and a minimum energy objective function is defined. To solve the problem, an indirect solution of the optimal control method is employed, and conditions of the optimality derived as a set of coupled nonlinear differential equations. The optimality equations are solved numerically, and various simulations are performed for a nonholonomic mobile robot to illustrate effectiveness of the proposed method.

关键词： mobile robot     trajectory planning     nonlinear dynamic     optimal control    

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标题 作者 时间 类型 操作

Capacity analysis for cognitive heterogeneous networks with ideal/non-ideal sensing

Tao HUANG, Ying-lei TENG, Meng-ting LIU, Jiang LIU

期刊论文

施工导流工程风险的保险费用厘定方法研究

陈志鼎,胡志根

期刊论文

多点协同传输机制下的多层无人机—地面异构网络覆盖性能分析

王维昊,蒋逸凡,费泽松,郭婧

期刊论文

Preparation and microstructure analysis of Fe-doped PbTiO ceramic

QIANG Liangsheng, MA Jing, CHU Jia, ZHANG Xiaohong

期刊论文

Effect of a less permeable stronger soil layer on the stability of non-homogeneous unsaturated slopes

Nabarun DEY, Aniruddha SENGUPTA

期刊论文

Control of homogeneous charge compression ignition combustion in a two-cylinder gasoline direct injection

WANG Zhi, WANG Jianxin, SHUAI Shijin, MA Qingjun, TIAN Guohong

期刊论文

Anaerobic treatment of wastewater containing methanol in up-flow anaerobic sludge bed (UASB) reactor

LIN Yishan, HE Yanling, MENG Zhuo, YANG Shucheng

期刊论文

Liquid discharge plasma for fast biomass liquefaction at mild conditions: The effects of homogeneous

Sen Wang, Shiyun Liu, Danhua Mei, Rusen Zhou, Congcong Jiang, Xianhui Zhang, Zhi Fang, Kostya (Ken) Ostrikov

期刊论文

Effects of compression ratio on the combustion characteristics of a homogeneous charge compression ignition

SONG Ruizhi, ZHOU Longbao, LIU Shenghua, LI Wei, HU Tiegang

期刊论文

Reactive adsorption desulfurization over a Ni/ZnO adsorbent prepared by homogeneous precipitation

Aihua KONG, Yanyu WEI, Yonghong LI

期刊论文

双层辉光离子渗金属技术特点

高原,徐晋勇,高清,安晋平,徐重

期刊论文

轴向零泊松比结构心血管支架的设计、3D打印与表征

王程锦, 张磊, 方永聪, 孙伟

期刊论文

Two-sided ultrasonic surface rolling process of aeroengine blades based on on-machine noncontact measurement

Shulei YAO, Xian CAO, Shuang LIU, Kaiming ZHANG, Xiancheng ZHANG, Congyang GONG, Chengcheng ZHANG

期刊论文

STRENGTHENING NON-POINT SOURCE POLLUTION CONTROL TO PROMOTE AGRICULTURAL GREEN DEVELOPMENT

期刊论文

Trajectory planning of mobile robots using indirect solution of optimal control method in generalized point-to-point

M. NAZEMIZADEH, H. N. RAHIMI, K. AMINI KHOIY

期刊论文