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Robust isogeometric topology optimization for piezoelectric actuators with uniform manufacturability

《机械工程前沿（英文）》 2022年 第17卷 第2期 doi: 10.1007/s11465-022-0683-5

摘要： Piezoelectric actuators have received substantial attention among the industry and academia due to quick responses, such as high output force, high stiffness, high accuracy, and precision. However, the design of piezoelectric actuators always suffers from the emergence of several localized hinges with only one-node connection, which have difficulty satisfying manufacturing and machining requirements (from the over- or under-etching devices). The main purpose of the current paper is to propose a robust isogeometric topology optimization (RITO) method for the design of piezoelectric actuators, which can effectively remove the critical issue induced by one-node connected hinges and simultaneously maintain uniform manufacturability in the optimized topologies. In RITO, the isogeometric analysis replacing the conventional finite element method is applied to compute the unknown electro elastic fields in piezoelectric materials, which can improve numerical accuracy and then enhance iterative stability. The erode–dilate operator is introduced in topology representation to construct the eroded, intermediate, and dilated density distribution functions by non-uniform rational B-splines. Finally, the RITO formulation for the design of piezoelectric materials is developed, and several numerical examples are performed to test the effectiveness and efficiency of the proposed RITO method.

关键词： piezoelectric actuator     isogeometric topology optimization     uniform manufacturability     robust formulation     density distribution function    

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Design, synthesis, biological activity and density function theory study of pyrazole derivatives containing

Xiaoming Ding, Zhiwen Zhai, Luping Lv, Zhaohui Sun, Xinghai Liu

《化学科学与工程前沿（英文）》 2017年 第11卷 第3期   页码 379-386 doi: 10.1007/s11705-017-1634-2

摘要： A variety of pyrazole derivatives containing 1,3,4-thiadiazole moiety were synthesized under microwave irradiation, and their structures were confirmed by H NMR and HRMS. They were evaluated for herbicidal and antifungal activities, and the results indicated that two compounds with a phenyl group ( ) and 4- -butylphenyl group ( ) possess good herbicidal activity for dicotyledon and with the inhibition of 90% for root and 80%–90% for stalk at 100 ppm respectively. The structure-activity relationship of compounds and was also studied by density function theory method.

关键词： pyrazole     1     3     4-thiadiazole     antifungal activity     herbicidal activity     density function theory    

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Application of gamma-ray attenuation technology in density measurement of a slurry reactor

Jian XU, Weisheng WEI, Kai ZHANG

《化学科学与工程前沿（英文）》 2010年 第4卷 第4期   页码 486-490 doi: 10.1007/s11705-010-0509-6

摘要： Axial density profile of the gas-liquid-solid mixture in a slurry bubble column was measured by gamma-ray attenuation technology. Several measures for improving measurement precision were presented based on the discussion on attenuation law. It was found that the response frequency and the ray intensity should be as high as possible to improve the measurement precision. The mass absorption coefficient depended on not the object’s thickness but the location where the object was placed between the ray source and the detector. The results showed that the density in the column decreases with the increase of column height, which indicates that the measurement by gamma-ray attenuation is reasonable.

关键词： slurry reactor     axial density distribution     gamma-ray attenuation technology    

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火灾标准火烟雾颗粒测量及粒径尺度分布函数研究

疏学明,郑魁,袁宏永,姚斌

《中国工程科学》 2005年 第7卷 第8期   页码 51-55

摘要：

烟雾是火灾探测的重要参量，烟雾颗粒粒径及其尺度分布直接影响到感烟探测器的灵敏度，而目前有关烟雾颗粒粒径的研究相当匮乏。采用扫描迁移率粒子测量仪对火灾标准火烟雾颗粒的粒径大小及其分布进行实验测量，并采用数学拟合方法系统研究了烟雾颗粒粒径分布函数，研究结果表明对数正态分布函数较好地描述了烟雾颗粒尺度分布特征，其结论有益于火灾探测基础研究的发展。

关键词： 烟雾     颗粒     粒径     分布函数    

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Soot size distribution in lightly sooting premixed flames of benzene and toluene

Wang LIU, Jiaqi ZHAI, Baiyang LIN, He LIN, Dong HAN

《能源前沿（英文）》 2020年 第14卷 第1期   页码 18-26 doi: 10.1007/s11708-020-0663-6

摘要： The evolution of particle size distribution function (PSDF) of soot in premixed flames of benzene and toluene was studied on a burner stabilized stagnation (BSS) flame platform. The cold gas velocities were changed to hold the maximum flame temperatures of different flames approximately constant. The PSDFs of all the test flames exhibited a bimodal distribution, i.e., a small-size nucleation mode and a large-size accumulation mode. It was observed that soot nucleation and particle growth in the benzene flame were stronger than those in the toluene flame at short residence times. At longer residence times, the PSDFs of the two flames were similar, and the toluene flame showed a larger particle size distribution range and a higher particle volume fraction than the benzene flame.

关键词： premixed flame     soot     particle size distribution function     benzene     toluene    

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A model for creep life prediction of thin tube using strain energy density as a function of stress triaxiality

Tahir MAHMOOD, Sangarapillai KANAPATHIPILLAI, Mahiuddin CHOWDHURY

《机械工程前沿（英文）》 2013年 第8卷 第2期   页码 181-186 doi: 10.1007/s11465-013-0257-7

摘要：

This paper demonstrates the application of a new multiaxial creep damage model developed by authors using stress traixiality to predict the failure time of a component made of 0.5%Cr-0.5%Mo-0.25%V low alloy steel. The model employs strain energy density and assumes that the uniaxial strain energy density of a component can be easily calculated and can be converted to multi-axial strain energy density by multiplying it to a function of stress trixiality which is a ratio of mean stress to equivalent stress. For comparison, an elastic-creep and elastic-plastic-creep finite element analysis (FEA) is performed to get multi-axial strain energy density of the component which is compared with the calculated strain energy density for both cases. The verification and application of the model are demonstrated by applying it to thin tube for which the experimental data are available. The predicted failure times by the model are compared with the experimental results. The results show that the proposed model is capable of predicting failure times of the component made of the above-mentioned material with an accuracy of 4.0%.

关键词： elastic-creep     elastic-plastic-creep     stress triaxiality     life prediction     pressure vessels     finite element analysis (FEA)    

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Assessment of wind energy potential in Gaza Strip

Juma Yousuf ALAYDI

《能源前沿（英文）》 2011年 第5卷 第3期   页码 297-304 doi: 10.1007/s11708-010-0134-6

摘要： The analysis of collected wind data at two sites in the Gaza Strip, namely, Gaza City and Gaza International Airport in Rafah city, is presented. The two sites are candidates for remote area wind energy applications. The purpose of this paper is to present the results of the assessment of wind energy potential in the Gaza Strip in order to evaluate the wind regimes for installing wind energy conversion systems for power generation. The data on wind speed, direction and frequency distribution are used to analyze wind energy characteristics and availability at some stations in the Gaza Strip. The vertical extrapolation was based on the power-law expression, and the wind energy and potential have been estimated at the wind turbine hub height of approximately 50 m. Furthermore, the values of the Weibull parameters and are determined from summary statistics of wind resource. Consequently, the wind power is estimated by adoption of the Weibull distribution expression. Based on the results of this paper, sites are recommended for wind energy exploitation in the Gaza Strip.

关键词： wind data     wind resource assessment     wind power density     wind energy     the Weibull distribution and Weibull parameters    

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Investigation on available wind energy at Tungku beach

M. G. YAZDANI, M. A. SALAM

《能源前沿（英文）》 2012年 第6卷 第3期   页码 275-279 doi: 10.1007/s11708-012-0194-x

摘要： In this paper, wind velocities and directions (sea and land) are recorded in different days and times. The data collected were compared with the weather data from the Brunei Darussalam Meteorological Service (BDMS) and the findings of other researchers and were found to be in good agreement. The potential of wind energy is predicted from the available data collected. The average generated power (forenoon and afternoon) is found to be 25 (mean) and 18 W (median), 101 (mean) and 73 W (median), 912 (mean) and 660 W (median), 10137 (mean) and 7331 W (median) for a rotor with a diameter of 2.5, 5, 15 and 50 m, respectively. The power density for wind farming is found to be 0.26 (mean) and 0.19 (median), 0.31 (mean) and 0.22 (median) for the rotor whose diameter is 2.5 and 50 m, respectively, while the average values are found to be 0.28 (mean) and 0.2 (median) for the rotor whose diameter is 5 and 15 m.

关键词： wind velocity     temperature     tower height     power density     Raleigh distribution     electrical power    

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Monte Carlo simulation of the diffusion-limited aggregating process of particle suspension systems

Jiajing XU, Lin ZHANG, Yongjian TANG, Wei DAI, Wenwen SHAN,

《化学科学与工程前沿（英文）》 2010年 第4卷 第3期   页码 270-274 doi: 10.1007/s11705-009-0273-7

摘要： The aggregating process of particle suspension systems is a very universal phenomena and crucial for various processes both in nature and in industry. In this paper, the aggregating process was simulated with off-lattice diffusion-limited cluster-cluster aggregation (DLCA) Monte Carlo programs. The self-similar fractal structures of aggregates have been clearly demonstrated by the statistical analysis of gyration radius distribution and the existence of a scaling distribution of the reduced cluster size. The fractal dimension determined from the relationship between mass and gyration radius of aggregates was 1.80 or so. The fractal dimension of the aggregates drawn from the radial distribution function and structure factor of a single aggregate is about 1.90–2.10. It was also showed that, along with the increasing of particle volume fraction, the fractal dimension will increase in a nearly square root manner, and the spatial range of the fractal structure appearing becomes narrower. Also, the gelation transition can only occur in a particle suspension system where the particle volume fraction is greater than a critical value.

关键词： cluster-cluster aggregation     distribution function     relationship     process     universal    

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论正态云模型的普适性

李德毅,刘常昱

《中国工程科学》 2004年 第6卷 第8期   页码 28-34

摘要：

分布函数是分析随机现象的重要工具，正态分布是最重要的概率分布，在自然科学和社会科学中应用广泛；隶属函数是模糊集合的基石，正态隶属函数也有广泛的应用。但是，精确确定一个模糊概念的隶属函数已经成为模糊学应用的瓶颈。云模型把随机性和模糊性结合起来，用数字特征熵，揭示随机性与模糊性的关联性，并用来表示一个定性概念的粒度。正态云模型通过期望、熵和超熵构成的特定结构发生器，生成定性概念的定量转换值，体现概念的不确定性。这种特定结构不但放宽了形成正态分布的前提条件，而且把精确确定隶属函数放宽到构造正态隶属度分布的期望函数，因而更具有普遍适用性，更简单、直接地完成了定性与定量之间的相互转换过程。

关键词： 正态分布函数     隶属度     正态云模型     概念粒度     普适性    

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Effect of current density on groundwater arsenite removal performance using air cathode electrocoagulation

《环境科学与工程前沿（英文）》 2021年 第15卷 第6期 doi: 10.1007/s11783-021-1399-1

摘要：

• With the same charge, current density had little effect on As(III) removal in ACEC.

关键词： Electrocoagulation     Air cathode     Arsenic     Current density     Energy consumption    

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Effects of exercise therapy on bone mineral density in early postmenopausal women: a controlled trial

Shilin DENG MD ,

《医学前沿（英文）》 2009年 第3卷 第3期   页码 323-329 doi: 10.1007/s11684-009-0061-2

摘要： The purpose of this article is to determine the effect of a well-designed combined aerobic, resistance, and extension exercise program on bone mineral density (BMD) in postmenopausal women. The population comprised 45 postmenopausal women, who exercised over 12months (exercise group), and 36 women who served as a non-training control group. BMD of the hip, and lumbar spine was measured at the baseline and 12th month. Repeated measurement analysis of variance and nonparametric test were utilized to compare differences between the exercise group and controls. Thirty-six out of 45 persons in the exercise group and 36 controls completed the study. Average compliance was 82.2% for the whole exercise group at the 12th month. All the subjects had decreased BMD, but the rate of bone loss was lower in the exercise group than in the control group at the L4 and hip. Although the exercise program in this study may probably reduce the rate of bone loss in weight-bearing skeletal sites, we do not suggest the exercise by itself be viewed as prevention or treatment for osteoporosis. Further, the exact dose-response relationship of exercise and bone mass in early postmenopause is not clear.

关键词： early postmenopausal women     bone mineral density     exercise     effects    

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density measurement for plastic injection molding via ultrasonic technology

《机械工程前沿（英文）》 2022年 第17卷 第4期 doi: 10.1007/s11465-022-0714-2

摘要： Density variation during the injection molding process directly reflects the state of plastic melt and contains valuable information for process monitoring and optimization. Therefore, in-situ density measurement is of great interest and has significant application value. The existing methods, such as pressure−volume−temperature (PVT) method, have the shortages of time-delay and high cost of sensors. This study is the first to propose an in-situ density measurement method using ultrasonic technology. The analyses of the time-domain and frequency-domain signals are combined in the proposed method. The ultrasonic velocity is obtained from the time-domain signals, and the acoustic impedance is computed through a full-spectral analysis of the frequency-domain signals. Experiments with different process conditions are conducted, including different melt temperature, injection speed, material, and mold structure. Results show that the proposed method has good agreement with the PVT method. The proposed method has the advantages of in-situ measurement, non-destructive, high accuracy, low cost, and is of great application value for the injection molding industry.

关键词： ultrasonic measurement     melt density     in-situ measurement     injection molding    

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一种新的基于卷积神经网络的人群计数方法 Research Articles

黄杰浩,遆晓光,吴俊德,陈瑷玥

《信息与电子工程前沿（英文）》 2020年 第21卷 第8期   页码 1119-1266 doi: 10.1631/FITEE.1900282

摘要： 人群密度估计是一项具有挑战性的任务，因为人群中人头大小存在大范围变化。现有方法均采用多列式结构卷积神经网络去适应这种变化，但会导致密度图上不同密度区域产生平均效应并引入额外噪声。为解决该问题，提出一种新的基于分割先验图的神经网络方法，在分割图基础上生成一个高质量且没有噪声的密度图。该网络主要包括两个部分，即头部的人群前景分割神经网络和尾部的人群回归神经网络。在数据集只提供单点人头标记的情况下，采用均匀函数生成人群头部的掩膜真值图。基于该真值图，前景分割网络输出人群分割图，可有效减少密度图中无人区域噪声。将人群分割图输入人群回归网络，后者能生成高质量人群密度图并提供准确的人数估计。在4个公开数据集（即ShanghaiTech、UCF-CC-50、WorldExpo’10和UCSD）上验证了所提方法有效性；其中，在ShanghaiTech part B和UCF-CC-50两个数据集上该方法取得了当前最好结果。

关键词： 人群计数；密度估计；分割先验图；均匀函数    

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Energy supply for water electrolysis systems using wind and solar energy to produce hydrogen: a case study of Iran

Mostafa REZAEI, Ali MOSTAFAEIPOUR, Mojtaba QOLIPOUR, Mozhgan MOMENI

《能源前沿（英文）》 2019年 第13卷 第3期   页码 539-550 doi: 10.1007/s11708-019-0635-x

摘要： Due to acute problems caused by fossil fuels that threaten the environment, conducting research on other types of energy carriers that are clean and renewable is of great importance. Since in the past few years hydrogen has been introduced as the future fuel, the aim of this study is to evaluate wind and solar energy potentials in prone areas of Iran by the Weibull distribution function (WDF) and the Angstrom-Prescott (AP) equation for hydrogen production. To this end, the meteorological data of solar radiation and wind speed recorded at 10 m height in the time interval of 3 h in a five-year period have been used. The findings indicate that Manjil and Zahedan with yearly wind and solar energy densities of 6004 (kWh/m ) and 2247 (kWh/m ), respectively, have the greatest amount of energy among the other cities. After examining three different types of commercial wind turbines and photovoltaic (PV) systems, it becomes clear that by utilizing one set of Gamesa G47 turbine, 91 kg/d of hydrogen, which provides energy for 91 car/week, can be produced in Manjil and will save about 1347 L of gasoline in the week. Besides, by installing one thousand sets of X21-345 PV systems in Zahedan, 20 kg/d of hydrogen, enough for 20 cars per week, can be generated and 296 L of gasoline can be saved. Finally, the RETScreen software is used to calculate the annual CO emission reduction after replacing gasoline with the produced hydrogen.

关键词： wind energy     solar energy     water electrolysis     hydrogen production     Weibull distribution function (WDF)     Angstrom-Prescott (AP) equation    

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标题 作者 时间 类型 操作

Robust isogeometric topology optimization for piezoelectric actuators with uniform manufacturability

期刊论文

Design, synthesis, biological activity and density function theory study of pyrazole derivatives containing

Xiaoming Ding, Zhiwen Zhai, Luping Lv, Zhaohui Sun, Xinghai Liu

期刊论文

Application of gamma-ray attenuation technology in density measurement of a slurry reactor

Jian XU, Weisheng WEI, Kai ZHANG

期刊论文

火灾标准火烟雾颗粒测量及粒径尺度分布函数研究

疏学明,郑魁,袁宏永,姚斌

期刊论文

Soot size distribution in lightly sooting premixed flames of benzene and toluene

Wang LIU, Jiaqi ZHAI, Baiyang LIN, He LIN, Dong HAN

期刊论文

A model for creep life prediction of thin tube using strain energy density as a function of stress triaxiality

Tahir MAHMOOD, Sangarapillai KANAPATHIPILLAI, Mahiuddin CHOWDHURY

期刊论文

Assessment of wind energy potential in Gaza Strip

Juma Yousuf ALAYDI

期刊论文

Investigation on available wind energy at Tungku beach

M. G. YAZDANI, M. A. SALAM

期刊论文

Monte Carlo simulation of the diffusion-limited aggregating process of particle suspension systems

Jiajing XU, Lin ZHANG, Yongjian TANG, Wei DAI, Wenwen SHAN,

期刊论文

论正态云模型的普适性

李德毅,刘常昱

期刊论文

Effect of current density on groundwater arsenite removal performance using air cathode electrocoagulation

期刊论文

Effects of exercise therapy on bone mineral density in early postmenopausal women: a controlled trial

Shilin DENG MD ,

期刊论文

density measurement for plastic injection molding via ultrasonic technology

期刊论文

一种新的基于卷积神经网络的人群计数方法

黄杰浩,遆晓光,吴俊德,陈瑷玥

期刊论文

Energy supply for water electrolysis systems using wind and solar energy to produce hydrogen: a case study of Iran

Mostafa REZAEI, Ali MOSTAFAEIPOUR, Mojtaba QOLIPOUR, Mozhgan MOMENI

期刊论文