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Influence of using amorphous silicon stack as front heterojunction structure on performance of interdigitated

Rui JIA,Ke TAO,Qiang LI,Xiaowan DAI,Hengchao SUN,Yun SUN,Zhi JIN,Xinyu LIU

《能源前沿（英文）》 2017年第11卷第1期页码 96-104 doi: 10.1007/s11708-016-0434-6

摘要： Interdigitated back contact-heterojunction (IBC-HJ) solar cells can have a conversion efficiency of over 25%. However, the front surface passivation and structure have a great influence on the properties of the IBC-HJ solar cell. In this paper, detailed numerical simulations have been performed to investigate the potential of front surface field (FSF) offered by stack of n-type doped and intrinsic amorphous silicon (a-Si) layers on the front surface of IBC-HJ solar cells. Simulations results clearly indicate that the electric field of FSF should be strong enough to repel minority carries and cumulate major carriers near the front surface. However, the over-strong electric field tends to drive electrons into a-Si layer, leading to severe recombination loss. The n-type doped amorphous silicon (n-a-Si) layer has been optimized in terms of doping level and thickness. The optimized intrinsic amorphous silicon (i-a-Si) layer should be as thin as possible with an energy band gap ( ) larger than 1.4 eV. In addition, the simulations concerning interface defects strongly suggest that FSF is essential when the front surface is not passivated perfectly. Without FSF, the IBC-HJ solar cells may become more sensitive to interface defect density.

关键词： amorphous silicon front surface field simulations interdigitated back contact-heterojunction solar cells

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Optimization of the O/HO process with response surface methodology for pretreatment of mother liquorof gas field wastewater

《环境科学与工程前沿（英文）》 2021年第15卷第4期 doi: 10.1007/s11783-020-1371-5

摘要：

• Real ML-GFW with high salinity and high organics was degraded by O₃/H₂O₂ process.

关键词： High salinity High organic matters Gas field wastewater O₃/H₂O₂ Response surface methodology

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Laboratory and field evaluation of asphalt pavement surface friction resistance

Zhong WU, Chris ABADIE

《结构与土木工程前沿（英文）》 2018年第12卷第3期页码 372-381 doi: 10.1007/s11709-017-0463-1

摘要：

Pavement surface friction is a significant factor for driving safety and plays a critical role in reducing wet-pavement crashes. However, the current asphalt mixture design procedure does not directly consider friction as a requirement. The objective of this study was to develop a surface friction prediction model that can be used during a wearing course mixture design. To achieve the objective, an experimental study was conducted on the frictional characteristics of typical wearing course mixtures in Louisiana. Twelve wearing course mixtures including dense-graded and open-graded mixes with different combinations of aggregate sources were evaluated in laboratory using an accelerated polishing and testing procedure considering both micro- and macro texture properties. In addition, the surface frictional properties of asphalt mixtures were measured on twenty-two selected asphalt pavement sections using different in situ devices including Dynamic Friction Tester (DFT), Circular Texture Meter (CTM), and Lock-Wheel Skid Trailer (LWST). The results have led to develop a procedure for predicting pavement end-of-life skid resistance based on the aggregate blend polish stone value, gradation parameters, and traffic, which is suited in checking whether the selected aggregates in a wearing course mix design would meet field friction requirements under a certain design traffic polishing.

关键词： friction skid resistance polishing PSV LWST micro-texture macro-texture

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investigation and analysis of heat transfer enhancement in channel by longitudinal vortex based on field

TAO Wenquan, WU Junmei

《能源前沿（英文）》 2008年第2卷第1期页码 71-78 doi: 10.1007/s11708-008-0001-x

摘要： 3-D numerical simulations were presented for laminar flow and heat transfer characteristics in a rectangular channel with vortex generators. The effects of Reynolds number (from 800 to 3 000), the attack angle of vortex generator (from 15° to 90°) and the shape of vortex generator were examined. The numerical results were analyzed based on the field synergy principle. It is found that the inherent mechanism of the heat transfer enhancement by longitudinal vortex can be explained by the field synergy principle, that is, the second flow generated by vortex generators results in the reduction of the intersection angle between the velocity and fluid temperature gradient. The longitudinal vortex improves the field synergy of the large downstream region of longitudinal vortex generator (LVG) and the region near (LVG); however, transverse vortex only improves the synergy of the region near vortex generator. Thus, longitudinal vortex can enhance the integral heat transfer of the flow field, while transverse vortex can only enhance the local heat transfer. The synergy angle decreases with the increase of Reynolds number for the channel with LVG to differ from the result obtained from the plain channel, and the triangle winglet performs better than the rectanglar one under the same surface area condition.

关键词： inherent mechanism integral surface rectanglar longitudinal

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新型PB-PSOI器件表面电场和温度分布模型研究

孙伟锋,高珊,陆生礼,陈军宁

《中国工程科学》 2009年第11卷第11期页码 82-87

摘要：

根据泊松方程和热扩散方程提出了新型PB-PSOI 器件漂移区的二维表面电场分布模型和温度分布模型，模型计算结果与Medici模拟结果相一致。根据所提出的模型，重点研究了埋氧化层厚度及长度对漂移区表面电场分布和温度分布的影响，最后给出了PB-PSOI 器件的埋氧化层厚度和长度的优化设计方法。

关键词： PB-PSOI 表面电场温度分布埋氧化层

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Numerical analysis on heat transfer enhancement by longitudinal vortex based on field synergy principle

WU Junmei, TAO Wenquan

《能源前沿（英文）》 2007年第1卷第3期页码 365-369 doi: 10.1007/s11708-007-0055-1

摘要： Three-dimensional numerical simulation results are presented for a fin-and-tube heat transfer surface with vortex generators. The effects of the Reynolds number (from 800 to 2 000) and the attack angle (30º and 45º) of a delta winglet vortex generator are examined. The numerical results are analyzed on the basis of the field synergy principle to explain the inherent mechanism of heat transfer enhancement by longitudinal vortex. The secondary flow generated by the vortex generators causes the reduction of the intersection angle between the velocity and fluid temperature gradients. In addition, the computational evaluations indicate that the heat transfer enhancement of delta winglet pairs for an aligned tube bank fin-and-tube surface is more significant than that for a staggered tube bank fin-and-tube surface. The heat transfer enhancement of the delta winglet pairs with an attack angle of 45º is larger than that with an angle of 30º. The delta winglet pair with an attack angle of 45º leads to an increase in pressure drop, while the delta winglet pair with the 30º angle results in a slight decrease. The heat transfer enhancement under identical pumping power condition for the attack angle of 30º is larger than that for the attack angle of 45º either for staggered or for aligned tube bank arrangement.

关键词： computational inherent mechanism staggered decrease transfer surface

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Shanghai center project excavation induced ground surface movements and deformations

Guolin XU, Jiwen ZHANG, Huang LIU, Changqin REN

《结构与土木工程前沿（英文）》 2018年第12卷第1期页码 26-43 doi: 10.1007/s11709-017-0439-1

摘要： Empirical data on deep urban excavations can provide designers a significant reference basis for assessing potential deformations of the deep excavations and their impact on adjacent structures. The construction of the Shanghai Center involved excavations in excess of 33-m-deep using the top-down method at a site underlain by thick deposits of marine soft clay. A retaining system was achieved by 50-m-deep diaphragm walls with six levels of struts. During construction, a comprehensive instrumentation program lasting 14 months was conducted to monitor the behaviors of this deep circular excavation. The following main items related to ground surface movements and deformations were collected: (1) walls and circumferential soils lateral movements; (2) peripheral soil deflection in layers and ground settlements; and (3) pit basal heave. The results from the field instrumentation showed that deflections of the site were strictly controlled and had no large movements that might lead to damage to the stability of the foundation pit. The field performance of another 21cylindrical excavations in top-down method were collected to compare with this case through statistical analysis. In addition, numerical analyses were conducted to compare with the observed data. The extensively monitored data are characterized and analyzed in this paper.

关键词： deep excavation foundation pit soft clay top-down method field observation ground surface movements ground deformations

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CRITICAL PROCESSES AND MAJOR FACTORS THAT DRIVE NITROGEN TRANSPORT FROM FARMLAND TO SURFACE WATER BODIES

《农业科学与工程前沿（英文）》 2023年第10卷第4期页码 541-552 doi: 10.15302/J-FASE-2023518

摘要：

Agricultural non-point source pollution is increasingly an important issue affecting surface water quality. Currently, the majority of the studies on nitrogen loss have focused on the agricultural field scale, however, the response of surface water quality at the watershed scale into the nitrogen loss at the field scale is poorly understood. The present study systematically reviewed the critical processes and major factors that nitrogen transport from farm fields to surface water bodies. The critical processes of farmland nitrogen entering surface water bodies involve the processes of nitrogen transport from farmland to ditches and the transformation processes of nitrogen during migration in ditches/rivers. Nitrogen transport from farmland to ditches is one of the prerequisites and critical processes for farmland nitrogen transport to surface water bodies. The transformation of nitrogen forms in ditches/rivers is an intermediate process in the migration of nitrogen from farmland to surface water bodies. Nitrogen loss from farmland is related to soil storage and exogenous inputs. Therefore, nitrogen input management should not only consider the current input, but also the contribution of soil storage due to the historical surpluses. Ditches/rivers have a strong retention capacity for nitrogen, which will significantly affect the process of farmland nitrogen entering surface water bodies. The factors affecting nitrogen transformation in river/ditches can be placed in four categories: (1) factors affecting hydraulic retention time, (2) factors affecting contact area, (3) factors affecting biological activity, and (4) forms and amount of nitrogen loading to river/ditches. Ditch systems are more biologically (including plants and microbes) active than rivers with biological factors having a greater influence on nitrogen transformation. When developing pollution prevention and control strategies, ecological ditches can be constructed to increase biological activity and reduce the amount of surplus nitrogen entering the water body. The present research should be valuable for the evaluation of environment impacts of nitrogen loss and the non-point source pollution control.

关键词： nitrogen loss from soil transformation farm field scale watershed scale

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基于3D变换电磁学和2D表面电磁学的电磁场操控和天线设计 Review

Peng-fei ZHANG, Yu-kai YAN, Ying LIU, Raj MITTRA

《信息与电子工程前沿（英文）》 2020年第21卷第3期页码 351-365 doi: 10.1631/FITEE.1900489

摘要：尽管人们已经开发了针对不同类型天线的多种设计技术，如线天线、贴片天线、透镜天线以及反射面等，但尚未构建普适的框架技术——普适框架技术应可用于各种天线的综合与设计，使天线具有满足使用者特定需求的电气特性。近年来，5G通信及各种空天技术、国防应用、生物医疗和类似应用的快速发展，迫切需要天线设计技术的大幅提升。本文从场操控角度剖视天线设计技术，为这种框架性构建提供一个可能的思考，以期最终部分满足这种需求。首先，回顾现有操控技术，包括基于麦克斯韦方程和波动方程在内的场变换方法，指出这些技术的局限性，并提出改善性能的方法。其次，介绍一种基于2D超表面的场操控方法及其理论基础——广义反射和折射定律。进一步，探索如何利用2D超表面克服传统的由临界角严格限制的反射和折射局限性。最后，给出场操控方法在天线设计中的应用实例，以期引导人们发展面向未来通信天线设计的通用策略和方法。

关键词：场操控；变换光学；天线设计；表面电磁学

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高海拔冻土区路基周边近地表流场特征及其工程意义

穆彦虎, 马巍, 杨朝晖, 栗晓林, 张坤, 毛运城

《工程（英文）》 2022年第14卷第7期页码 169-180 doi: 10.1016/j.eng.2021.10.020

摘要：

块碎石、通风管和热管等主动冷却措施广泛应用于冻土区工程建设，通过强化冷季与外界空气的换热过程降低下伏多年冻土的温度，进而确保气候变暖背景下工程构筑物的长期稳定性。对于气冷类主动冷却措施而言，对流换热过程至关重要，因此掌握构筑物周边流场特征具有重要的意义。结合青藏高原北麓河高等级公路试验示范工程，沿垂直于路基走向的横剖面开展了路基周边近地表流场的长期定位观测。基于6 个观测塔完整的一年观测数据，研究了路基两侧60 m范围内地面以上0.5 m、1.5 m、3.0 m和4.5 m高度上风速、风向的空间分布特征及季节变化规律。结果表明，路基的存在对近地表流场有显著的影响，在背风侧的影响距离可达10 倍路基高度。路基周边近地表风速沿高度的分布可用综合幂次律描述，幂次值为0.14~0.4；远离路基位置幂次值年均水平为0.19，与以往研究中常用值存在差异。讨论了近地表风场的空间分布和季节变化对包括块石、通风管等气冷路基结构工作机制和长期效果的影响，认为低估近地表风场速度剖面的幂次值、忽略风向的季节变化可能导致气冷类主动冷却降温措施设计的不足。现场测试结果可为高原冻土区工程建设提供有益参考。

关键词：进地表流场现场观测气冷措施线性交通工程青藏高原

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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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A review on front end conversion in ocean wave energy converters

Nagulan SANTHOSH,Venkatesan BASKARAN,Arunachalam AMARKARTHIK

《能源前沿（英文）》 2015年第9卷第3期页码 297-310 doi: 10.1007/s11708-015-0370-x

摘要： Harvesting the energy from ocean waves is one of the greatest attractions for energy engineers and scientists. Till date, plenty of methods have been adopted to harvest the energy from the ocean waves. However, due to technological and economical complexity, it is intricate to involve the majority of these energy harvesters in the real ocean environment. Effective utilization and sustainability of any wave energy harvester depend upon its adaptability in the irregular seasonal waves, situation capability in maximum energy extraction and finally fulfilling the economic barriers. In this paper, the front end energy conversions are reviewed in detail which is positioned in the first stage of the wave energy converter among other stages such as power take off (PTO) and electrical energy conversion. If the recent development of these front end energy conversion is well known then developing wave energy converter with economic and commercial viability is possible. The aim of this review is to provide information on front end energy conversion of a point absorber and emphasize the strategies and calamity to be considered in designing such kinds of devices to improve the energy harvesting competence. This will be useful to the engineers for speeding up the development of a matured point absorbing type wave energy converter.

关键词： wave energy converter point absorbers power take off (PTO) front end energy conversion

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Review: Tip-based vibrational spectroscopy for nanoscale analysis of emerging energy materials

Amun JARZEMBSKI, Cedric SHASKEY, Keunhan PARK

《能源前沿（英文）》 2018年第12卷第1期页码 43-71 doi: 10.1007/s11708-018-0524-8

摘要： Vibrational spectroscopy is one of the key instrumentations that provide non-invasive investigation of structural and chemical composition for both organic and inorganic materials. However, diffraction of light fundamentally limits the spatial resolution of far-field vibrational spectroscopy to roughly half the wavelength. In this article, we thoroughly review the integration of atomic force microscopy (AFM) with vibrational spectroscopy to enable the nanoscale characterization of emerging energy materials, which has not been possible with far-field optical techniques. The discussed methods utilize the AFM tip as a nanoscopic tool to extract spatially resolved electronic or molecular vibrational resonance spectra of a sample illuminated by a visible or infrared (IR) light source. The absorption of light by electrons or individual functional groups within molecules leads to changes in the sample’s thermal response, optical scattering, and atomic force interactions, all of which can be readily probed by an AFM tip. For example, photothermal induced resonance (PTIR) spectroscopy methods measure a sample’s local thermal expansion or temperature rise. Therefore, they use the AFM tip as a thermal detector to directly relate absorbed IR light to the thermal response of a sample. Optical scattering methods based on scanning near-field optical microscopy (SNOM) correlate the spectrum of scattered near-field light with molecular vibrational modes. More recently, photo-induced force microscopy (PiFM) has been developed to measure the change of the optical force gradient due to the light absorption by molecular vibrational resonances using AFM’s superb sensitivity in detecting tip-sample force interactions. Such recent efforts successfully breech the diffraction limit of light to provide nanoscale spatial resolution of vibrational spectroscopy, which will become a critical technique for characterizing novel energy materials.

关键词： vibrational spectroscopy atomic force microscopy photo-thermal induced resonance scanning near-field optical microscopy tip-enhanced Raman spectroscopy photo-induced force microscopy molecular resonances surface phonon polaritons energy materials

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Ultramicrostructure and clinical implications of satellite foci in front of the head of pterygium

LIU Haixia, XIANG Nan, ZHOU Xiongwu, HU Weikun, LI Guigang, ZHANG Hong

《医学前沿（英文）》 2007年第1卷第2期页码 211-214 doi: 10.1007/s11684-007-0040-4

摘要： In our previous studies, grey satellite foci were found in the front of heads of pterygia. This research was designed to investigate the ultramicrostructure and clinical implications of these satellite foci. The satellite foci were observed and counted under slit lamp biomicroscope. The patients with eye pterygia were divided into groups in terms of occupation, sex, age, length of history, grade of congestion, and size of the heads. The SPSS 13.0 software was used for statistical analysis. The cap areas and satellite foci were ultramicrostructurally examined. Among the total 62 eyes with pterygium, satellite foci were found in 34. The overall incidence of satellite foci was 54.8%. There were no significant differences in incidence among the subjects of different sex, age, and length of history. There were significant differences in incidence among the patients of different occupation, grades of congestion, and size of heads. Higher grades of congestion, outdoor occupations and larger pterygium heads were associated with higher incidence of satellite foci. High grades of congestion and bigger heads were also correlated with the number of satellite foci. Length of history bore no correlation with number of satellite foci. Histologically, the components of the cap areas and the foci were identical, with both consisting of mass of active fibroblasts. The activated fibroblasts existed in the natural tissue planes between Bowman s layer and basal cell layer. The fibroblasts in the satellite foci and the cap areas of a pterygium show some features of tumor cells and may play a vital role in the development and progression of a pterygium. The presence and amount of satellite foci around a pterygium can be used as an indicator for the speed of its growth.

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A family of non-conforming crack front elements of quadrilateral and triangular types for 3D crack problems

Guizhong XIE, Fenglin ZHOU, Hao LI, Xiaoyu WEN, Fannian MENG

《机械工程前沿（英文）》 2019年第14卷第3期页码 332-341 doi: 10.1007/s11465-019-0540-3

摘要： This study focuses on establishing non-conforming crack front elements of quadrilateral and triangular types for 3D crack problems when the dual boundary element method is applied. The asymptotic behavior of the physical variables in the area near the crack front is fully considered in the construction of the shape function. In the developed quadrilateral and triangular crack front elements, the asymptotic term, which captures the asymptotic behavior of the physical variable, is multiplied directly by the conventional Lagrange shape function to form a new crack front shape function. Several benchmark numerical examples that consider penny-shaped cracks and straight-edge crack problems are presented to illustrate the validity and efficiency of the developed crack front elements.

关键词： Taylor expansion crack front elements stress intensity factors dual boundary element method