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2016年熊本地震 1

3D打印 1

ALOS-2 PALSAR-2 1

BFT 1

Cuk矩阵变换器 1

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Mie散射 1

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Effect of cutterhead configuration on tunnel face stability during shield machine maintenance outages

《结构与土木工程前沿（英文）》 2023年第17卷第4期页码 522-532 doi: 10.1007/s11709-023-0930-9

摘要： Owing to long-distance advancement or obstacles, shield tunneling machines are typically shut down for maintenance. Engineering safety during maintenance outages is determined by the stability of the tunnel face. Pressure maintenance openings are typically used under complicated hydrogeological conditions. The tunnel face is supported by a medium at the bottom of the excavation chamber and compressed air at the top. Owing to the high risk of face failure, the necessity of support pressure when cutterhead support is implemented and a method for determining the value of compressed air pressure using different support ratios must to be determined. In this study, a non-fully chamber supported rotational failure model considering cutterhead support is developed based on the upper-bound theorem of limit analysis. Numerical simulation is conducted to verify the accuracy of the proposed model. The results indicate that appropriately increasing the specific gravity of the supporting medium can reduce the risk of collapse. The required compressed air pressure increases significantly as the support ratio decreases. Disregarding the supporting effect of the cutterhead will result in a tunnel face with underestimated stability. To satisfy the requirement of chamber openings at atmospheric pressure, the stratum reinforcement strength and range at the shield end are provided based on different cutterhead aperture ratios.

关键词： tunnel face stability cutterhead configuration aperture ratio pressure gradient support ratio

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error control and crack-free surface fabrication techniques for ultra-precision fly cutting of large-aperture

F. H. ZHANG, S. F. WANG, C. H. AN, J. WANG, Q. XU

《机械工程前沿（英文）》 2017年第12卷第2期页码 193-202 doi: 10.1007/s11465-017-0448-8

摘要：

Large-aperture potassium dihydrogen phosphate (KDP) crystals are widely used in the laser path of inertial confinement fusion (ICF) systems. The most common method of manufacturing half-meter KDP crystals is ultra-precision fly cutting. When processing KDP crystals by ultra-precision fly cutting, the dynamic characteristics of the fly cutting machine and fluctuations in the fly cutting environment are translated into surface errors at different spatial frequency bands. These machining errors should be suppressed effectively to guarantee that KDP crystals meet the full-band machining accuracy specified in the evaluation index. In this study, the anisotropic machinability of KDP crystals and the causes of typical surface errors in ultra-precision fly cutting of the material are investigated. The structures of the fly cutting machine and existing processing parameters are optimized to improve the machined surface quality. The findings are theoretically and practically important in the development of high-energy laser systems in China.

关键词： ultra-precision fly cutting large-aperture KDP crystals spatial frequency processing error

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大相对口径大线视场光学系统的设计

潘君骅

《中国工程科学》 2000年第2卷第8期页码 89-90

摘要：

文章论述了用于红外远距离探测的光学应是全反射式的大相对口径、大视场的离轴非球面系统。给出了一个通光口径为Φ600mm，相对口径1:1.67，线视场为±5°的设计结果。

关键词：红外探测相对口径大视场离轴系统非球面

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油压极值比与极值比效率

齐茂林

《中国工程科学》 2001年第3卷第4期页码 73-75

摘要：

文章应用基础公式，推导液压系统油压极值比与极值比效率之间的关系式。该式说明，油压极值比越大，极值比效率就越低。提出了油压极值比是可以设计和选择的。

关键词：油压极值比极值比效率液压系统

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用于SAR图像分类的统计分布基元特征 Article

Chu HE, Ya-ping YE, Ling TIAN, Guo-peng YANG, Dong CHEN

《信息与电子工程前沿（英文）》 2017年第18卷第10期页码 1614-1623 doi: 10.1631/FITEE.1601051

摘要： None

关键词： None

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Controlling interstory drift ratio profiles via topology optimization strategies

《结构与土木工程前沿（英文）》 2023年第17卷第2期页码 165-178 doi: 10.1007/s11709-022-0892-3

摘要： An approach to control the profiles of interstory drift ratios along the height of building structures via topology optimization is proposed herein. The theoretical foundation of the proposed approach involves solving a min–max optimization problem to suppress the maximum interstory drift ratio among all stories. Two formulations are suggested: one inherits the bound formulation and the other utilizes a p-norm function to aggregate all individual interstory drift ratios. The proposed methodology can shape the interstory drift ratio profiles into inverted triangular or quadratic patterns because it realizes profile control using a group of shape weight coefficients. The proposed formulations are validated via a series of numerical examples. The disparity between the two formulations is clear. The optimization results show the optimal structural features for controlling the interstory drift ratios under different requirements.

关键词： interstory drift ratio aggregation function bound formulation min–max problem topology optimization

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利用地球同步轨道InSAR每日生成DEM的质量分析 Article

杨泽发, 张庆君, 丁晓利, 陈武

《工程（英文）》 2020年第6卷第8期页码 913-918 doi: 10.1016/j.eng.2020.07.003

摘要：

最新的数字高程模型（DEM）产品在灾害防治、城市管理等诸多领域中扮演着重要角色。利用机载或低地球轨道（LEO）的星载干涉合成孔径雷达（InSAR）生成DEM已被证明是可行且极具价值的方法。然而，受成本和卫星重返周期的限制，该技术难以频繁（如每天）生成或更新大区域范围（如大陆尺度或更大范围）的DEM。由于对地同步合成孔径雷达（GEOSAR）卫星运行于地球静止轨道，因此它们能以相当短的重返时间（每天或更短）观测同一地面区域，这为实现生成每日DEM这一理想但目前难以实现的目标提供了潜在可能。为此，本文系统地分析了利用GEOSAR卫星生成的每日DEM产品质量。结果表明：GEOSAR卫星生成的每日DEM产品精度通常远低于利用传统低轨星载合成孔径雷达（SAR）获得的DEM产品。因此，研究GEOSAR DEM生成过程中的误差削弱方法显得至关重要。

关键词：每日DEM生成 InSAR 地球同步SAR 精度分析

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A methodology of implementing target mixing ratio for asphalt mixture

Yucheng HUANG, Lun JI, Rui WEN, Ming ZHANG

《结构与土木工程前沿（英文）》 2017年第11卷第3期页码 308-314 doi: 10.1007/s11709-017-0405-y

摘要： In order to implement the objective mix design of hot mix asphalt adequately during the construction process, the significance of objective mixing ratio was elaborated, and the variability of materials and its control method were analyzed. An engineering example is used to illustrate the debugging process of asphalt mixture batching & mixing plant and the dynamic quality management methods. The results show that the set of methods can not only implement the objective mixing ratio of hot mix asphalt adequately, but also control production during the construction process effectively.

关键词： asphalt mixture target mixing ratio mix design implementation batching & mixing plant debugging

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Diagnostic evaluation of plasma aldosterone concentration to plasma renin activity ratio in primary aldosteronism

ZHANG Huilan, WANG Daowen

《医学前沿（英文）》 2008年第2卷第1期页码 11-14 doi: 10.1007/s11684-008-0003-4

摘要： Using the plasma aldosterone concentration to plasma renin activity ratio (PAC/PRA ratio) as the screening test of choice for primary aldosteronism in hypertensive patients, we studied the clinical characteristics and the diagnostic value of PAC/PRA ratio in primary aldosteronism. The plasma aldosterone concentration (PAC) and plasma renin activity (PRA) levels were measured by radioimmunoassay in 902 hypertensive patients from out-patient clinics or hospitals. One hundred and twenty-six suspected primary aldosteronism patients whose PAC/PRA ratio was > 25 ng/dL/ng/mL/hr had a lamellar computed tomography (CT) scan in the adrenal gland and follow-up visits. The proportion of primary aldosteronism in hypertensive patients was 14% (126/902). There were 54 patients with unilateral or bilateral hyperplasia and 25 patients with adenoma according to the CT scan. 39% (49/126) of the patients with primary aldosteronism had hypokalemia. Twenty-five patients received surgical treatment. The efficacy and cure rates were 100% (25/25) and 48% (12/25), respectively. The effective rate of aldactone and the single-drug cure rate were 89% (48/54) and 24% (13/54), respectively. Primary aldosteronism affects over 10% of hypertensive patients in China. The PAC/PRA ratio can be considered as a routine screening test in hypertensives, especially resistant hypertensive patients and a high PAC/PRA ratio is an invaluable index in primary aldosteronism diagnosis.

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大而复杂形变区域中的精确三维形变反演——基于偏移的相位解缠和改进的多孔径SAR干涉测量集成技术在2016年熊本地震中的应用 Article

Won-Kyung Baek, Hyung-Sup Jung

《工程（英文）》 2020年第6卷第8期页码 927-935 doi: 10.1016/j.eng.2020.06.012

摘要：

常规合成孔径雷达（synthetic aperture radar, SAR）干涉测量（InSAR）已成功用于精确测量雷达视线（line-of-sight, LOS）方向上的表面形变，而多孔径SAR干涉技术（multiple-aperture SAR interferometry, MAI）可以用于精确测量沿轨迹（along-track, AT）方向的表面形变。形变反演使用了两组升轨对和一组高级陆地观测卫星2（Advanced Land Observing Satellite-2, ALOS-2）相控阵型L波段合成孔径雷达2（Phased Array-type L-band Synthetic Aperture

关键词：合成孔径雷达（SAR）常规SAR干涉测量（InSAR）多孔径SAR干涉技术（MAI） ALOS-2 PALSAR-2 三维形变反演 2016年熊本地震

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多孔径光学成像系统及其光场采集数学模型 Review Article

祁启明,傅瑞罡,邵铮铮,王平,范红旗

《信息与电子工程前沿（英文）》 2022年第23卷第6期页码 823-844 doi: 10.1631/FITEE.2100058

摘要：

受昆虫复眼启发，为提高光学成像质量，如获得高分辨率图像或大视场图像，研究者提出了许多多孔径光学成像系统。光场采集数学模型是联系多孔径光学成像系统结构设计与应用的纽带，但光场采集数学模型较少被关注。本文系统梳理了典型多孔径光学成像系统（仿生复眼、光场相机、相机阵列），总结了不同结构下多孔径光学成像系统的一般性光场采集数学模型。列出的数学模型既可用于计算特定多孔径光学成像系统的关键指标，如视场大小和子图像重叠比等，也可作为数学工具，便于研究者完成对成像系统的定量设计与评估。

关键词：多孔径光学成像系统；仿生复眼；光场相机；相机阵列；光场采集模型

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Enhancing the efficiency of nitrogen removing bacterial population to a wide range of C:N ratio (1.5:

《环境科学与工程前沿（英文）》 2022年第16卷第8期 doi: 10.1007/s11783-022-1522-y

摘要：

• Simultaneous C & N removal in Methammox occurs at wide C:N ratio.

关键词： Methanogens Biological Nitrogen Removal (BNR) Simultaneous Methammox C:N ratio

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Experimental study of structural damage identification based on modal parameters and decay ratio of acceleration

Zhigen WU, Guohua LIU, Zihua ZHANG

《结构与土木工程前沿（英文）》 2011年第5卷第1期页码 112-120 doi: 10.1007/s11709-010-0069-3

摘要： A novel damage assessment method based on the decay ratio of acceleration signals (DRAS) was proposed. Two experimental tests were used to show the efficiency. Three beams were gradually damaged, and then the changes of dynamic parameters were monitored from initial to failure state. In addition, a new method was compared with the linear modal-based damage assessment using wavelet transform (WT). The results clearly show that DRAS increases in linear elasticity state and microcrack propagation state, while DRAS decreases in macrocrack propagation state. Preliminary analysis was developed considering the beat phenomenon in the nonlinear state to explain the turn point of DRAS. With better sensibility of damage than modal parameters, probably DRAS is a promising damage indicator in damage assessment.

关键词： damage assessment decay ratio of acceleration signals (DRAS) wavelet transform (WT) modal analysis reinforced concrete beam beat phenomenon

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The influence of the NCO/OH ratio and the 1,6-hexanediol/dimethylol propionic acid molar ratio on the

Jiao Feng, Qiuhao Lu, Weimin Tan, Kequan Chen, Pingkai Ouyang

《化学科学与工程前沿（英文）》 2019年第13卷第1期页码 80-89 doi: 10.1007/s11705-018-1763-2

摘要：

1,5-Pentamethylene diisocyanate, a novel aliphatic diisocyanate formed from bio-based 1,5-pentamethylenediamine, has been used as a hard segmented material to synthesize polyurethane. In this study, several waterborne polyurethane (WPU) dispersions have been successfully prepared by a prepolymer process from 1,5-pentamethylene diisocyanate poly(polyether) with different NCO/OH ratios and 1,6-hexanediol (HDO)/dimethylol propionic acid (DMPA) molar ratios. The Fourier transform infrared (FTIR) spectra, thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction, and a mechanical tensile test were used to investigate the structures, thermal stability, phase separation, crystallinity, mechanical properties, and adhesive performance of the WPU dispersions. The FTIR results indicate that the degree of hydrogen bonding and the numbers of urea groups increase as the NCO/OH ratio and HDO/DMPA molar ratio increase. Furthermore, the phase separation increases and the thermal stability decreases as the NCO/OH ratio increases or the HDO/DMPA molar ratio decreases. Finally, WPU3.0-2.4 (NCO/OH=3, HDO/DMPA=2.4) exhibits a maximum tensile strength and shear strength, pointing to its possible use as an adhesive. These results could provide a very valuable reference for industrial applications of WPU.

关键词： 1 5-pentamethylene diisocyanate polyurethane water based

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Long term performance of recycled concrete beams with different water–cement ratio and recycled aggregate

Jingwei YING; Feiming SU; Shuangren CHEN

《结构与土木工程前沿（英文）》 2022年第16卷第3期页码 302-315 doi: 10.1007/s11709-022-0803-7

摘要： The purpose of this study is to reveal the service performance of recycled aggregate concrete (RAC) components for different values of water−cement ratio and replacement rate of recycled coarse aggregate (RCA). Generally, the concrete strength decreases with the increase of the replacement rate of RCA, in order to meet the strength requirements when changing the replacement rate of RCA, it is necessary to change the water−cement ratio at the same time. Therefore, the axial compressive strengths of prism with 25 mix proportions, the short-term mechanical properties and long-term deformation properties of reinforced concrete beams were tested respectively by changing water−cement ratio and RCA replacement rate. The bearing capacity and the strain nephogram of samples under different loads were obtained using the Digital Image Correlation (DIC) method, and a self-made gravity loading experimental device was used for long-term deformation investigation. Results showed that the damage pattern of RAC was the same as that of natural aggregate concrete (NAC), but the brittleness was more pronounced. The brittleness of concrete before failure can be reduced more effectively by adjusting the replacement rate of RCA than by adjusting the water−cement ratio. The water−cement ratio has an evident influence on the axial compressive strength and early creep of concrete, while the replacement rate of RCA has a remarkable effect on the long-term deformation of the concrete beams.

关键词： recycled concrete beam the replacement rate of recycled coarse aggregate water–cement ratio digital image correlation