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Optical performance analysis of an innovative linear focus secondary trough solar concentrating system

Xiliang ZHANG, Zhiying CUI, Jianhan ZHANG, Fengwu BAI, Zhifeng WANG

《能源前沿（英文）》 2019年 第13卷 第3期   页码 590-596 doi: 10.1007/s11708-018-0602-y

摘要： The parabolic trough solar concentrating system has been well developed and widely used in commercial solar thermal power plants. However, the conventional system has its drawbacks when connecting receiver tube parts and enhancing the concentration ratio. To overcome those inherent disadvantages, in this paper, an innovative concept of linear focus secondary trough concentrating system was proposed, which consists of a fixed parabolic trough concentrator, one or more heliostats, and a fixed tube receiver. The proposed system not only avoids the end loss and connection problem on the receiver during the tracking process but also opens up the possibility to increase the concentration ratio by enlarging aperture. The design scheme of the proposed system was elaborated in detail in this paper. Besides, the optical performance of the semi and the whole secondary solar trough concentrator was evaluated by using the ray tracing method. This innovative solar concentrating system shows a high application value as a solar energy experimental device.

关键词： secondary parabolic trough solar concentrator     ray tracing method     linear focus     concentration ratio     optical performance    

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射线与三角Bézier曲面交点的混合裁剪算法 Article

Yan-hong LIU,Juan CAO,Zhong-gui CHEN,Xiao-ming ZENG

《信息与电子工程前沿（英文）》 2016年 第17卷 第10期   页码 1018-1030 doi: 10.1631/FITEE.1500390

摘要： 概要：本文提出了一种快速、稳定的几何算法来求解射线与三角Bézier曲面的交点，我们把这种新方法称为混合裁剪算法（简称HC（hybrid clipping）算法）。若射线只穿过曲面一次，通过降阶逼近算法，我们得到参数域上的一对直线和一对二次曲线，进而可将交点的参数范围限定在一个比原参数域更小的三角域上。结合细分算法，原三角域可以被反复剪裁，直到参数域的直径小于给定的阈值。当射线与曲面的交点个数大于1时，本文利用Descartes符号法则和细分算法将参数域分割成一些子区域，使得每个子区域只包含一个交点。本文从理论上证明了，经过适当的预处理，HC算法在单根的情况下具有三阶的收敛速度。此外，HC算法具有许多优良的性质，如无需初始值以及对初始问题扰动不敏感等。数值实验也表明了HC算法在解决射线与三角Bézier曲面求交问题的有效性。

关键词： 光线跟踪；三角Bézier曲面；射线与曲面的交点；求根；混合裁剪    

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基于多声源波速结构成像的岩体异常区域超前辨识方法 Article

董陇军, 裴重伟, 谢鑫, 张义涵, 闫先航

《工程（英文）》 2023年 第22卷 第3期   页码 191-200 doi: 10.1016/j.eng.2022.05.016

摘要： 开展了数值和室内实验，量化评估最短路径法（shortest-path method, SPM）、动态最短路径法（dynamic shortest-path method, DSPM）和快速扫描法（fastsweeping method, FSM）等正演模拟的识别精度和计算效率。

关键词： 地下工程     走时层析     复杂结构     异常区域辨识     射线追踪    

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A novel period estimation method for X-ray pulsars based on frequency subdivision

Li-rong SHEN,Xiao-ping LI,Hai-feng SUN,Hai-yan FANG,Meng-fan XUE

《信息与电子工程前沿（英文）》 2015年 第16卷 第10期   页码 858-870 doi: 10.1631/FITEE.1500052

摘要： Period estimation of X-ray pulsars plays an important role in X-ray pulsar based navigation (XPNAV). The fast Lomb periodogram is suitable for period estimation of X-ray pulsars, but its performance in terms of frequency resolution is limited by data length and observation time. Longer observation time or oversampling can be employed to improve frequency analysis results, but with greatly increased computational complexity and large amounts of sampling data. This greatly restricts real-time autonomous navigation based on X-ray pulsars. To resolve this issue, a new method based on frequency subdivision and the continuous Lomb periodogram (CLP) is proposed to improve precision of period estimation using short-time observation data. In the proposed method, an initial frequency is first calculated using fast Lomb periodogram. Then frequency subdivision is performed near the initial frequency to obtain frequencies with higher precision. Finally, a refined period is achieved by calculating the CLP in the obtained frequencies. Real data experiments show that when observation time is shorter than 135 s, the proposed method improves period estimation precision by 1–3 orders of magnitude compared with the fast Lomb periodogram and fast Fourier transform (FFT) methods, with only a slight increase in computational complexity. Furthermore, the proposed method performs better than efsearch (a period estimation method of HEAsoft) with lower computational complexity. The proposed method is suitable for estimating periods of X-ray pulsars and obtaining the rotation period of variable stars and other celestial bodies.

关键词： Pulsar navigation     Period estimation     Frequency subdivision     Continuous Lomb periodogram    

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Sensory innervation of the anterior eye segment in rats: a retrograde tracing study

Haixia LIU MD , Zhiwang LI MD , Min YANG MD , Xiang TIAN MS , Chaoying LI PhD , Lei PEI PhD ,

《医学前沿（英文）》 2009年 第3卷 第3期   页码 352-356 doi: 10.1007/s11684-009-0065-y

摘要： This study aimed to investigate the sensory innervation of the anterior eye segment in rats by retrograde tracing with 1,1-dioleyl-3,3,3,3-tetrameth-ylindocarbocyanine, 4-chlorobenesulfonate (FAST Dil) injected into the anterior chamber. In our study, the sensory innervation of distinct elements of the anterior segment of the rat’s eye, i.e. the cornea, ciliary body, iris, and trabecular meshwork, were studied by retrograde tracing using FAST Dil as a tracer. FAST Dil was injected into the anterior chambers of the rat’s eyes. The animals were sacrificed at different time points, i.e., 2, 3, 4, and 5 days after the injection. FAST Dil localization in trigeminal ganglions was studied with a fluorescent microscope. Two days after FAST Dil injection into the anterior chambers, the cornea, the ciliary body, the iris, and the trabecular meshwork were heavily labeled. Neurons in the ipsilateral trigeminal ganglion were also consistently labeled. The number of labeled cells increased over time until 4 days after FAST Dil injection. FAST Dil-labeled neurons could be divided into two parts. Most of the Dil-labeled neurons were concentrated in a sharp, longitudinal, spindle-like stripe, located in the dorso-medial side of the trigeminal ganglion, approximately two thirds of the dorsal portion. The other part of Dil-labeled neurons scattered laterally to the stripe, but just in one third of the dorsal region. Thus, with our preliminary results, we conclude that the primary afferent sensory neurons innervating the rat’s anterior eye segments aggregate in the dorso-medial part of the ipsilateral trigeminal ganglion. It is feasible to identify them using retrograde tracing with FAST Dil anterior chamber injection.

关键词： trigeminal ganglion     retrograde tracing    

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选区激光熔化纯钨——粉末粒径对激光吸收的影响和扫描轨迹形成机理研究 Article

章佳窈, 顾冬冬, 杨莹, 张红梅, 陈洪宇, 戴冬华, 林开杰

《工程（英文）》 2019年 第5卷 第4期   页码 736-745 doi: 10.1016/j.eng.2019.07.003

摘要：

本文建立了基于线迹追踪的三维激光吸收模型，用于描述选区激光熔化（SLM）成形纯钨粉末时激光束与粉末层的相互作用，研究了粉末粒径大小对粉末激光吸收率和吸收行为的影响。本文给出了激光吸收率、粉层吸收辐照度及其分布、激光扫描轨迹的表面形貌和几何特征（如接触角、宽度和高度，以及重熔深度）之间的内在关系。模拟结果表明，粉末层的吸收率大大超过单一的粉末颗粒或致密平板材料的吸收率。随着粉末粒径增加，粉末层吸收的激光能量减少。当粒径为5 μm时，纯钨粉末层的吸收率最大达到0.6030。激光辐照度在粉床颗粒表面的分布与粒径大小、方位角和粉末在基板上的位置有关。当粒径从5 μm增加到45 μm时，粉末层中的最大辐照度从1.117 × 10–3 W·μm–2降低到0.85 × 10–3 W·μm–2，并且位于中心辐照区域的辐照度分布轮廓逐渐收缩。对SLM纯钨扫描轨迹的表面形貌和横截面几何特征进行了研究，结果验证了模拟的粉末激光吸收行为。该工作对线迹追踪模型预测SLM扫描轨迹润湿性和铺展性的应用提供了科学依据，从而更好地获得优异的激光成形性能。

关键词： 选区激光熔化     钨     线迹追踪模型     吸收率     激光扫描轨迹    

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基于机器学习的空地通信高度相关视距概率经验性模型 Research Article

庞明慧1,2,朱秋明1,2,林志鹏1,柏菲1,田越1,李茁3,陈小敏1

《信息与电子工程前沿（英文）》 2022年 第23卷 第9期   页码 1378-1389 doi: 10.1631/FITEE.2200041

摘要： 仿真表明该模型获得的结果与射线追踪（ray trancing, RT）数据、实测数据和标准模型结果具有良好一致性。

关键词： 视距概率模型；空地信道；机器学习；射线跟踪    

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Fatigue of asphalt binder, mastic and mixture at low temperature

Dong WANG, Linbing WANG, Guoqing ZHOU

《结构与土木工程前沿（英文）》 2012年 第6卷 第2期   页码 166-175 doi: 10.1007/s11709-012-0157-7

摘要： The fatigue damage is one of the most common distresses observed on the asphalt concrete pavement. To thoroughly understand the fatigue of asphalt concrete, the behaviors of the major components of asphalt concrete under cyclic loading are investigated respectively in this study. A new experiment method is developed to evaluate the performances of asphalt binder, mastic and fine aggregates mixture under cyclic tensile loading. The fatigue test results of asphalt binder show that the fatigue performance of asphalt binder is closely related with loading magnitude, temperature and loading rate. Mastic specimens with different filler content are tested and the results indicate that mastic specimens with 30% filler content show better fatigue resistance and higher permanent strain. The micro-structure analysis of mastic and mixture indicates that the fatigue resistance is closely related with the air void content of specimen. 3D digital specimens are developed to model the fatigue of the asphalt binder, mastic and mixture specimens based on the finite element method (FEM). Fatigue damage of asphalt concrete is simplified by a damage model. With proper selection of damage parameters, the simulation results agree well with laboratory test results and can be used as a basis for future fatigue research.

关键词： fatigue     asphalt mixture     asphalt binder     mastic     finite element method (FEM)     X-ray tomography    

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A study on quality evaluation for bituminous mixture using X-ray CT

Satoshi TANIGUCHI, Keiichiro OGAWA, Jun OTANI, Itaru NISHIZAKI

《结构与土木工程前沿（英文）》 2013年 第7卷 第2期   页码 89-101 doi: 10.1007/s11709-013-0197-7

摘要： The objective of this paper is to propose a new quality evaluation method for asphalt concrete mixture using X-ray CT scanner. To achieve this aim, asphalt mixtures should be subjected to the X-ray CT scanning and its characteristics should be clarified. The approach employed in this study was as follows: 1) Coarse aggregate, fine aggregate, filler and bitumen were prepared; 2) dense-graded, coarse-graded and porous asphalt mixtures were made; 3) materials and mixtures were subjected to the X-ray CT scanning; 4) frequency of CT-value, threshold value, average slice CT-value, average segment CT-value were computed. In the material examination, CT-value of aggregate becomes smaller in the order of coarse aggregate, fine aggregate and filler and CT image of bitumen was nearly homogeneous. In the mixture examination, histograms of CT-value and four segmentation images made from CT images expressed the material and mixture characterization such as particle size and the difference in bitumen content and mixture type visibly and the bitumen content varies with the threshold values. In addition, the average segment CT-value without threshold value by dividing the fine aggregate from the coarse aggregate and average CT-value of the coarse aggregate, especially is highly correlated with average CT-value of the bitumen.

关键词： asphalt concrete mixture     aggregate     bitumen     bitumen content     quality evaluation     X-ray CT    

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Adsorption of fluoride on clay minerals and their mechanisms using X-ray photoelectron spectroscopy

Junyi DU, Daishe WU, Huayun XIAO, Ping LI

《环境科学与工程前沿（英文）》 2011年 第5卷 第2期   页码 212-226 doi: 10.1007/s11783-010-0255-5

摘要： This research investigates the adsorption mechanisms of fluoride (F) on four clay minerals (kaolinite, montmorillonite, chlorite, and illite) under different F concentrations and reaction times by probing their fluoride superficial layer binding energies and element compositions using X-ray photoelectron spectroscopy (XPS). At high F concentrations ( = 5–1000 mg·L ), the amount of F adsorbed ( ), amount of hydroxide released by clay minerals, solution F concentration, and the pH increase with increasing . The increases are remarkable at >50 mg·L . The increases significantly by continuously modifying the pH level. At <5–100 mg·L , clay minerals adsorb H to protonate aluminum-bound surface-active hydroxyl sites in the superficial layers and induce F binding. As the increases, F , along with other cations, is adsorbed to form a quasi-cryolite structure. At >100 mg·L , new minerals precipitate and the product depends on the critical Al concentration. At [Al ]>10 mol·L , cryolite forms, while at [Al ]<10 mol·L , AlF is formed. At low (0.3–1.5 mg·L ), proton transfer occurs, and the F adsorption capabilities of the clay minerals increase with time.

关键词： clay mineral     fluoride (F)     adsorption mechanism     X-ray photoelectron spectroscopy (XPS)    

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Optimization and modeling of coagulation-flocculation to remove algae and organic matter from surface water by response surface methodology

Ray, Ajay K Ray, Tianyin Huang, Jiabin Chen

《环境科学与工程前沿（英文）》 2019年 第13卷 第5期 doi: 10.1007/s11783-019-1159-7

摘要： Charge neutralization and sweep flocculation were the major mechanisms. Effect of process parameters was investigated. Optimal coagulation conditions were studied by response surface methodology. ANN models presented more robust and accurate prediction than RSM. Seasonal algal blooms of Lake Yangcheng highlight the necessity to develop an effective and optimal water treatment process to enhance the removal of algae and dissolved organic matter (DOM). In the present study, the coagulation performance for the removal of algae, turbidity, dissolved organic carbon (DOC) and ultraviolet absorbance at 254 nm (UV254) was investigated systematically by central composite design (CCD) using response surface methodology (RSM). The regression models were developed to illustrate the relationships between coagulation performance and experimental variables. Analysis of variance (ANOVA) was performed to test the significance of the response surface models. It can be concluded that the major mechanisms of coagulation to remove algae and DOM were charge neutralization and sweep flocculation at a pH range of 4.66–6.34. The optimal coagulation conditions with coagulant dosage of 7.57 mg Al/L, pH of 5.42 and initial algal cell density of 3.83 × 106 cell/mL led to removal of 96.76%, 97.64%, 40.23% and 30.12% in term of cell density, turbidity, DOC and UV254 absorbance, respectively, which were in good agreement with the validation experimental results. A comparison between the modeling results derived through both ANOVA and artificial neural networks (ANN) based on experimental data showed a high correlation coefficient, which indicated that the models were significant and fitted well with experimental results. The results proposed a valuable reference for the treatment of algae-laden surface water in practical application by the optimal coagulation-flocculation process.

关键词： Algae     Coagulation-flocculation     Response surface methodology     Artificial neural networks    

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Establishing two-stage interaction between fly ash and NaOH by X-ray and infrared analyses

Bhagwanjee JHA,Nevin KOSHY,Devendra Narain SINGH

《环境科学与工程前沿（英文）》 2015年 第9卷 第2期   页码 216-221 doi: 10.1007/s11783-014-0630-8

摘要： The interaction of the fly ash and NaOH, in an open reflux hydrothermal system at 100°C, has been explored by several researchers and formation of fly ash zeolites has been confirmed based on the X-ray diffraction analysis of the residues. However, this method does not reveal much about the characteristic transitions (viz. elemental, electro-negativity and cation exchange capacity) of the residues. In this situation, resorting to Fourier transform-infrared radiation (FT-IR) spectroscopy on the residues obtained from two-stage hydrothermal treatment process, described in this manuscript, appears to be a novel idea to establish transitions in chemical bonds (viz., -Si-OH-Al-, OH-Na, OH-Al-), crystallinity and cation exchange capacity of these residues. Based on extensive studies, it has been demonstrated that FT-IR spectroscopy is extremely useful for 1) detection of chemical bonds in the residues, 2) evaluation of zeolites in the residues and 3) also establishing the superiority of the two-stage interaction of the fly ash with NaOH for synthesizing better fly ash zeolites (viz., Na-P1 and Hydroxysodalte) as compared to those obtained from the conventional single-stage treatment of the fly ash.

关键词： hydrothermal treatment     alkali activation     fly ash zeolites     X-ray diffraction (XRD) and Fourier transform-infrared radiation (FT-IR) spectroscopy    

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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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Heat Integration retrofit analysis—an oil refinery case study by Retrofit Tracing Grid Diagram

Andreja NEMET, Jiří Jaromír KLEMEŠ, Petar Sabev VARBANOV, Valter MANTELLI

《化学科学与工程前沿（英文）》 2015年 第9卷 第2期   页码 163-182 doi: 10.1007/s11705-015-1520-8

摘要： Heat Integration has been established over the last decades as a proven chemical engineering methodology. Two design implementations are often used in the industry: grassroots and retrofit. Although various methods have been developed for retrofit, it still needs more development to ensure simultaneously thermodynamic feasibility and economic viability. In this paper, a novel graphical approach has been developed to facilitate the understanding of the current situation and scope of improvement. The Retrofit Tracing Grid Diagram presents all streams and heat exchangers in temperature scale and the heat exchangers are clearly separated from each other, enabling clear visualisation of the current state. The tool incorporates the previously developed Cross-Pinch Analysis as well as path approach for retrofit. Additionally, the non-vertical heat transfer can be evaluated. The application of the developed tool has been validated on an oil refinery case study. The applicability of the tool is evident as it can reveal additional options for modification that none of the previous methods considered.

关键词： Heat Integration     retrofit     Pinch Analysis     thermodynamic approach     oil refinery    

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Design of efficient Pt-based electrocatalysts through characterization by X-ray absorption spectroscopy

Nebojsa S. MARINKOVIC, Kotaro SASAKI, Radoslav R. ADZIC

《能源前沿（英文）》 2017年 第11卷 第3期   页码 236-244 doi: 10.1007/s11708-017-0487-1

摘要： A method is described to determine the internal structure of electrocatalyst nanoparticles by X-ray absorption spectroscopy (XAS). The nondestructive spectroscopic technique typically utilizing synchrotron radiation as the source measures changes in the X-ray absorption coefficient as a function of energy. The bulk technique has found its use for materials characterization in all scientific areas, including nanomaterials. The analysis of the internal structure of nanoparticles reveals interatomic distances and coordination numbers for each element, and their values and mutual relations indicate whether the elements form a homogeneous or heterogeneous mixture. The core-shell heterogeneous structure in which certain elements are predominantly located in the core, and others form the encapsulating shell is of particular importance in catalysis and electrocatalysis because it may reduce the amount of precious metals in nanoparticles by replacing the atoms in the core of nanoparticles with more abundant and cheaper alternatives. The examples of nanoparticle structures designed in the laboratory and the approach to model efficient catalysts through systematic analysis of XAS data in electrochemical systems consisting of two and three metals are also demonstrated.

关键词： X-ray absorption spectroscopy     EXAFS     XANES     nanocatalysts     core shell    

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标题 作者 时间 类型 操作

Optical performance analysis of an innovative linear focus secondary trough solar concentrating system

Xiliang ZHANG, Zhiying CUI, Jianhan ZHANG, Fengwu BAI, Zhifeng WANG

期刊论文

射线与三角Bézier曲面交点的混合裁剪算法

Yan-hong LIU,Juan CAO,Zhong-gui CHEN,Xiao-ming ZENG

期刊论文

基于多声源波速结构成像的岩体异常区域超前辨识方法

董陇军, 裴重伟, 谢鑫, 张义涵, 闫先航

期刊论文

A novel period estimation method for X-ray pulsars based on frequency subdivision

Li-rong SHEN,Xiao-ping LI,Hai-feng SUN,Hai-yan FANG,Meng-fan XUE

期刊论文

Sensory innervation of the anterior eye segment in rats: a retrograde tracing study

Haixia LIU MD , Zhiwang LI MD , Min YANG MD , Xiang TIAN MS , Chaoying LI PhD , Lei PEI PhD ,

期刊论文

选区激光熔化纯钨——粉末粒径对激光吸收的影响和扫描轨迹形成机理研究

章佳窈, 顾冬冬, 杨莹, 张红梅, 陈洪宇, 戴冬华, 林开杰

期刊论文

基于机器学习的空地通信高度相关视距概率经验性模型

庞明慧1,2,朱秋明1,2,林志鹏1,柏菲1,田越1,李茁3,陈小敏1

期刊论文

Fatigue of asphalt binder, mastic and mixture at low temperature

Dong WANG, Linbing WANG, Guoqing ZHOU

期刊论文

A study on quality evaluation for bituminous mixture using X-ray CT

Satoshi TANIGUCHI, Keiichiro OGAWA, Jun OTANI, Itaru NISHIZAKI

期刊论文

Adsorption of fluoride on clay minerals and their mechanisms using X-ray photoelectron spectroscopy

Junyi DU, Daishe WU, Huayun XIAO, Ping LI

期刊论文

Optimization and modeling of coagulation-flocculation to remove algae and organic matter from surface water by response surface methodology

Ray, Ajay K Ray, Tianyin Huang, Jiabin Chen

期刊论文

Establishing two-stage interaction between fly ash and NaOH by X-ray and infrared analyses

Bhagwanjee JHA,Nevin KOSHY,Devendra Narain SINGH

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

Heat Integration retrofit analysis—an oil refinery case study by Retrofit Tracing Grid Diagram

Andreja NEMET, Jiří Jaromír KLEMEŠ, Petar Sabev VARBANOV, Valter MANTELLI

期刊论文

Design of efficient Pt-based electrocatalysts through characterization by X-ray absorption spectroscopy

Nebojsa S. MARINKOVIC, Kotaro SASAKI, Radoslav R. ADZIC

期刊论文