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多晶硅 3

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Characterization of random stress fields obtained from polycrystalline aggregate calculations using multi-scale

Bruno SUDRET,Hung Xuan DANG,Marc BERVEILLER,Asmahana ZEGHADI,Thierry YALAMAS

《结构与土木工程前沿（英文）》 2015年 第9卷 第2期   页码 121-140 doi: 10.1007/s11709-015-0290-1

摘要： The spatial variability of stress fields resulting from polycrystalline aggregate calculations involving random grain geometry and crystal orientations is investigated. A periodogram-based method is proposed to identify the properties of homogeneous Gaussian random fields (power spectral density and related covariance structure). Based on a set of finite element polycrystalline aggregate calculations the properties of the maximal principal stress field are identified. Two cases are considered, using either a fixed or random grain geometry. The stability of the method w.r.t the number of samples and the load level (up to 3.5% macroscopic deformation) is investigated.

关键词： polycrystalline aggregates     crystal plasticity     random fields     spatial variability     correlation structure    

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Sub-nanometer finishing of polycrystalline tin by inductively coupled plasma-assisted cutting

《机械工程前沿（英文）》 2023年 第18卷 第3期 doi: 10.1007/s11465-023-0751-5

摘要： Polycrystalline tin is an ideal excitation material for extreme ultraviolet light sources. However, the existence of grain boundary (GB) limits the surface roughness of polycrystalline tin after single-point diamond turning (SPDT). In this work, a novel method termed inductively coupled plasma (ICP)-assisted cutting was developed for the sub-nanometer finishing of polycrystalline tin. The relationship between ICP power, processing time, and modification depth was established by thermodynamic simulation, and the fitted heat transfer coefficient of polycrystalline tin was 540 W/(m2·K). The effects of large-thermal-gradient ICP treatment on the microstructure of polycrystalline tin were studied. After 0.9 kW ICP processing for 3.0 s, corresponding to the temperature gradient of 0.30 K/µm, the grain size of polycrystalline tin was expanded from a size of approximately 20–80 μm to a millimeter scale. The Taguchi method was used to investigate the effects of rotational speed, depth of cut, and feed rate on SPDT. Experiments conducted based on the ICP system indicated that the plasma-assisted cutting method promoted the reduction of the influence of GB steps on the finishing of polycrystalline tin, thereby achieving a surface finish from 8.53 to 0.80 nm in Sa. The results of residual stress release demonstrated that the residual stress of plasma-assisted turning processing after 504 h stress release was 10.7 MPa, while that of the turning process without the ICP treatment was 41.6 MPa.

关键词： plasma-assisted cutting     polycrystalline tin     single-point diamond turning     surface roughness    

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MICROBIAL NECROMASS WITHIN AGGREGATES STABILIZES PHYSICALLY-PROTECTED C RESPONSE TO CROPLAND MANAGEMENT

《农业科学与工程前沿（英文）》 2023年 第10卷 第2期   页码 198-209 doi: 10.15302/J-FASE-2023498

摘要：

● The contribution of fungal necromass C to SOC increased with aggregate sizes.

关键词： cropland management     microbial necromass     soil aggregates     soil carbon sequestration     soil organic matter    

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Industrial bio-based plant aggregates as hygric and insulating construction materials for energy efficient

Yunhong Jiang, Mike Lawrence, Meng Zhang, Jiandong Cui

《化学科学与工程前沿（英文）》 2022年 第16卷 第10期   页码 1532-1532 doi: 10.1007/s11705-020-1960-7

摘要： In this paper, the bulk density, microstructure, porosity and pore size distribution of the selected aggregates, including hemp shiv, flax shiv, rape shiv and wheat straw, are fully studied due to these properties are highly related to their excellent characteristics and more or less linked to the properties of the final product. The scanning electron microscope results showed all the selected aggregates have a highly porous and complex hierarchical structure, whereas the arrangement of pores and the thickness of cell wall are significantly different among these aggregates. All the selected aggregates had a low bulk density ranging from 30 to 130 kg∙m and a high porosity between 75.81% and 88.74%. The thermal conductivity of the selected bio-aggregates ranged from 0.04 to 0.06 W∙m ∙K . The thermal conductivity of the selected aggregates was not only depending on the bulk density of the sample but also depending on the raw material. Hemp shiv, rape shiv and flax shiv were excellent hygric regulators with moisture buffer value ( ) ranging from 2.07 to 2.36 g∙m ∙%RH , whereas, wheat straw had a lower MBV value ranging from 1.76 to 1.97 g∙m ∙%RH . The results showed that particle size does not affect the value. The value increases linearly with bulk density.

关键词： bio-based aggregates     density     porosity     thermal conductivity     hygric properties    

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Retraction note to: Industrial bio-based plant aggregates as hygric and insulating construction materials

Yunhong Jiang, Mike Lawrence, Meng Zhang, Jiandong Cui

《化学科学与工程前沿（英文）》 doi: 10.1007/s11705-021-2039-9

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兴建年产一千吨电子级多晶硅工厂的思考

梁骏吾

《中国工程科学》 2000年 第2卷 第6期   页码 33-35

摘要：

文章简要评述了世界以及中国的电子级多晶硅的生产能力和市场需求。在2000年和2010年中国对多晶硅的需求分别是736 t/a和1304 t/a。但近几年中国的多晶硅生产仅达到80 t/a，所以在中国建设一座年产1000 t电子级多晶硅的工厂是很合理的。然而由最新统计数据可知，自1997年以来，世界多晶硅生产能力连年均超过市场需求，而且在最近的将来，这一趋势将会继续。为了占领国内多晶硅市场，未来的多晶硅工厂将面临挑战，产品质量和生产成本是应当考虑的最重要指标。为了占领国内市场，在保证多晶硅产品纯度的前提下，生产成本只能略微超过20美元/kg。

关键词： 多晶硅     半导体工业     规模生产    

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Chloride diffusion in concrete with carbonated recycled coarse aggregates under biaxial compression

《结构与土木工程前沿（英文）》 2023年 第17卷 第4期   页码 637-648 doi: 10.1007/s11709-023-0902-0

摘要： Chloride attack on concrete structures is affected by the complex stress state inside concrete, and the effect of recycled aggregates renders this process more complex. Enhancing the chloride resistance of recycled concrete in a complex environment via carbonization facilitates the popularization and application of recycled concrete and alleviates the greenhouse effect. In this study, the chloride ion diffusion and deformation properties of recycled concrete after carbonization are investigated using a chloride salt load-coupling device. The results obtained demonstrate that the chloride ion diffusivity of recycled concrete first decreases and then increases as the compressive load increases, which is consistent with the behavior of concrete, in that it first undergoes compressive deformation, followed by crack propagation. Carbonation enhances the performance of the recycled aggregates and reduces their porosity, thereby reducing the chloride diffusion coefficient of the recycled concrete under different compressive load combinations. The variation in the chloride ion diffusivity of the carbonized recycled aggregate concrete with the load is consistent with a theoretical formula.

关键词： recycled concrete     carbonated recycled coarse aggregate     biaxial compression     chloride diffusion     stress level    

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Laboratory assessment of Alaska aggregates using Micro-Deval test

Jenny LIU,Sheng ZHAO,Anthony MULLIN

《结构与土木工程前沿（英文）》 2017年 第11卷 第1期   页码 27-34 doi: 10.1007/s11709-016-0359-5

摘要： Aggregates suitable for use in asphalt concrete (AC) pavement construction must meet durability criteria. Thus, it is critical to select appropriate tests to properly characterize aggregate durability. In Alaska, durability tests currently being used for aggregates in AC pavement include Los Angeles (LA) abrasion test, sulfate soundness test and Washington degradation test. However, there have long been concerns arising over Washington degradation test used as an acceptance tool, motivating pavement practitioners to seek more suitable alternatives. This paper presents a study to investigate the feasibility of using Micro-Deval test, commonly used in other states, to evaluate the durability of Alaskan aggregates in AC pavement as well as its potential to replace Washington degradation test. Micro-Deval test, Washington degradation test and other tests currently specified in Alaska were conducted on aggregates from 16 batches representing statewide sources. Based on the testing results, it is found that using Micro-Deval test for durability assessment of Alaska aggregates was feasible and reproducible, and a high potential was revealed to use Micro-Deval test to replace Washington degradation test in Alaska. It is recommended that Micro-Deval test be considered as an additional test for a certain period, but in the long run should be used along with current LA abrasion and sulfate soundness tests to provide a more desirable durability assessment of Alaska aggregates used in AC pavement.

关键词： aggregate durability     Washington degradation test     Micro-Deval test    

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A thermoelectric generator and water-cooling assisted high conversion efficiency polycrystalline silicon

Zekun LIU, Shuang YUAN, Yi YUAN, Guojian LI, Qiang WANG

《能源前沿（英文）》 2021年 第15卷 第2期   页码 358-366 doi: 10.1007/s11708-020-0712-1

摘要： Solar energy has been increasing its share in the global energy structure. However, the thermal radiation brought by sunlight will attenuate the efficiency of solar cells. To reduce the temperature of the photovoltaic (PV) cell and improve the utilization efficiency of solar energy, a hybrid system composed of the PV cell, a thermoelectric generator (TEG), and a water-cooled plate (WCP) was manufactured. The WCP cannot only cool the PV cell, but also effectively generate additional electric energy with the TEG using the waste heat of the PV cell. The changes in the efficiency and power density of the hybrid system were obtained by real time monitoring. The thermal and electrical tests were performed at different irradiations and the same experiment temperature of 22°C. At a light intensity of 1000 W/m , the steady-state temperature of the PV cell decreases from 86.8°C to 54.1°C, and the overall efficiency increases from 15.6% to 21.1%. At a light intensity of 800 W/m , the steady-state temperature of the PV cell decreases from 70°C to 45.8°C, and the overall efficiency increases from 9.28% to 12.59%. At a light intensity of 400 W/m , the steady-state temperature of the PV cell decreases from 38.5°C to 31.5°C, and the overall efficiency is approximately 3.8%, basically remain unchanged.

关键词： photovoltaic (PV)     thermoelectric generator     conversion efficiency     hybrid energy systems     water-cooled plate (WCP)    

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Effects of coarse and fine aggregates on long-term mechanical properties of sea sand recycled aggregate

《结构与土木工程前沿（英文）》 2021年 第15卷 第3期   页码 754-772 doi: 10.1007/s11709-021-0711-2

摘要： Typical effects of coarse and fine aggregates on the long-term properties of sea sand recycled aggregate concrete (SSRAC) are analyzed by a series of axial compression tests. Two different types of fine (coarse) aggregates are considered: sea sand and river sand (natural and recycled coarse aggregates). Variations in SSRAC properties at different ages are investigated. A novel test system is developed via axial compression experiments and the digital image correlation method to obtain the deformation field and crack development of concrete. Supportive results show that the compressive strength of SSRAC increase with decreasing recycled coarse aggregate replacement percentage and increasing sea sand chloride ion content. The elastic modulus of SSRAC increases with age. However, the Poisson’s ratio reduces after 2 years. Typical axial stress–strain curves of SSRAC vary with age. Generally, the effect of coarse aggregates on the axial deformation of SSRAC is clear; however, the deformation differences between coarse aggregate and cement mortar reduce by adopting sea sand. The aggregate type changes the crack characteristics and propagation of SSRAC. Finally, an analytical expression is suggested to construct the long-term stress–strain curve of SSRAC.

关键词： sea sand recycled aggregate concrete     recycled coarse aggregate replacement percentage     sea sand chloride ion content     long-term mechanical properties     stress–strain curve    

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电子级多晶硅的生产工艺

梁骏吾

《中国工程科学》 2000年 第2卷 第12期   页码 34-39

摘要：

就建设1000t电子级多晶硅厂的技术进行了探讨。对三氣氢硅法、四氣化硅法、二氣二氢硅法和硅烷法生产的多晶硅质量、安全性、运输和存贮的可行性、有用沉积比、沉积速率、一次转换率、生长温度、电耗和价格进行了对比；对还原或热分解使用的反应器即钟罩式反应器、流床反应器和自由空间反应器也进行了比较。介绍了用三氣氢硅钟罩式反应器法生产多晶硅三代流程。第三代多晶硅流程适于1000t/a级的电子级多晶硅生产。

关键词： 多晶硅     三氣氢硅法     硅烷法     流程     生产    

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Microprofiles of activated sludge aggregates using microelectrodes in completely autotrophic nitrogen

Yongtao LV,Xuan CHEN,Lei WANG,Kai JU,Xiaoqiang CHEN,Rui MIAO,Xudong WANG

《环境科学与工程前沿（英文）》 2016年 第10卷 第2期   页码 390-398 doi: 10.1007/s11783-015-0818-6

摘要： Microsensor measurements and fluorescence in situ hybridization (FISH) analysis were combined to investigate the microbial populations and activities in a laboratory-scale sequencing batch reactor (SBR) for completely autotrophic nitrogen removal over nitrite (CANON). Fed with synthetic wastewater rich in ammonia, the SBR removed 82.5±5.4% of influent nitrogen and a maximum nitrogen-removal rate of 0.52 kgN·m ·d was achieved. The FISH analysis revealed that aerobic ammonium-oxidizing bacteria (AerAOB) and anaerobic ammonium-oxidizing bacteria (AnAOB) dominated the community. To quantify the microbial activities inside the sludge aggregates, microprofiles were measured using pH, dissolved oxygen (DO), , and microelectrodes. In the outer layer of sludge aggregates (0–700 μm), nitrite-oxidizing bacteria (NOB) showed high activity with 4.1 μmol·cm ·h of maximum nitrate production rate under the condition of DO concentration higher than 3.3 mg·L . Maximum AerAOB activity was detected in the middle layer (depths around 1700 μm) where DO concentration was 1.1 mg·L . In the inner layer (2200–3500 μm), where DO concentration was below 0.9 mg·L , AnAOB activity was detected. We thus showed that information obtained from microscopic views can be helpful in optimizing the SBR performance.

关键词： microelectrodes     CANON     aerobic ammonium-oxidizing bacteria     anaerobic ammonium-oxidizing bacteria     nitrite-oxidizing bacteria    

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Study on micro-texture and skid resistance of aggregate during polishing

Zhenyu QIAN, Lingjian MENG

《结构与土木工程前沿（英文）》 2017年 第11卷 第3期   页码 346-352 doi: 10.1007/s11709-017-0409-7

摘要： The skid resistance performance of pavement is closely related to the micro-texture of pavement aggregate, while there is very few research on the relationship between micro-texture and the skid resistance. In this paper, the optical microscope is used to acquire the surface morphology of three types of aggregates including basalt, limestone and red sandstone respectively, where a total of 12 indicators are developed based on the surface texture information. The polishing effect on aggregate is simulated by Wehner/Schulze (W/S) device, during the polishing procedure, the skid resistance are measured by British Pendulum Tester (BPT). Based on the results of independent T-test and the polishing resistance analysis, it shows that the surface texture of basalt is significantly different between limestone and red sandstone. Three indicators including the average roughness ( ), the kurtosis of the surface ( ) and the mean summit curvature ( ) are selected to describe the characteristics of aggregate micro-texture based on the correlation analysis. The contribution of micro-texture to the skid resistance can be described with the secondary polynomial regression model by these indicators.

关键词： skid resistance of pavement     micro-texture     aggregates     polishing test    

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Ultimate bearing capacity of strip footing resting on clay soil mixed with tire-derived aggregates

《结构与土木工程前沿（英文）》 2021年 第15卷 第4期   页码 1016-1024 doi: 10.1007/s11709-021-0751-7

摘要： This study investigated the use of recycled tire-derived aggregate (TDA) mixed with kaolin as a method of increasing the ultimate bearing capacity ( UBC) of a strip footing. Thirteen 1g physical modeling tests were prepared in a rigid box of 0.6 m × 0.9 m in plan and 0.6 m in height. During sample preparation, 0%, 20%, 40%, or 60% (by weight) of powdery, shredded, small-sized granular (G 1–4 mm) or large-sized granular (G 5–8 mm) TDA was mixed with the kaolin. A strip footing was then placed on the stabilized kaolin and was caused to fail under stress-controlled conditions to determine the UBC. A rigorous 3D finite element analysis was developed in Optum G-3 to determine the UBC values based on the experimental test results. The experimental results showed that, except for the 20% powdery TDA, the TDA showed an increase in the UBC of the strip footing. When kaolin mixed with 20% G (5–8 mm), the UBC showed a threefold increase over that for the unreinforced case. The test with 20% G (1–4 mm) recorded the highest subgrade modulus. It was observed that the UBC calculated using finite element modeling overestimated the experimental UBC by an average of 9%.

关键词： kaolin     physical modeling tests     stabilization     numerical modeling    

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Destructive and non-destructive evaluation of concrete for optimum sand to aggregate volume ratio

《结构与土木工程前沿（英文）》 2021年 第15卷 第6期   页码 1400-1414 doi: 10.1007/s11709-021-0779-8

摘要： Aggregates are the biggest contributor to concrete volume and are a crucial parameter in dictating its mechanical properties. As such, a detailed experimental investigation was carried out to evaluate the effect of sand-to-aggregate volume ratio (s/a) on the mechanical properties of concrete utilizing both destructive and non-destructive testing (employing UPV (ultrasonic pulse velocity) measurements). For investigation, standard cylindrical concrete samples were made with different s/a (0.36, 0.40, 0.44, 0.48, 0.52, and 0.56), cement content (340 and 450 kg/m3), water-to-cement ratio (0.45 and 0.50), and maximum aggregate size (12 and 19 mm). The effect of these design parameters on the 7, 14, and 28 d compressive strength, tensile strength, elastic modulus, and UPV of concrete were assessed. The careful analysis demonstrates that aggregate proportions and size need to be optimized for formulating mix designs; optimum ratios of s/a were found to be 0.40 and 0.44 for the maximum aggregate size of 12 and 19 mm, respectively, irrespective of the W/C (water-to-cement) and cement content.

关键词： aggregates     non-destructive testing     sand-to-aggregate volume ratio (s/a)     maximum aggregate size (MAS)    

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标题 作者 时间 类型 操作

Characterization of random stress fields obtained from polycrystalline aggregate calculations using multi-scale

Bruno SUDRET,Hung Xuan DANG,Marc BERVEILLER,Asmahana ZEGHADI,Thierry YALAMAS

期刊论文

Sub-nanometer finishing of polycrystalline tin by inductively coupled plasma-assisted cutting

期刊论文

MICROBIAL NECROMASS WITHIN AGGREGATES STABILIZES PHYSICALLY-PROTECTED C RESPONSE TO CROPLAND MANAGEMENT

期刊论文

Industrial bio-based plant aggregates as hygric and insulating construction materials for energy efficient

Yunhong Jiang, Mike Lawrence, Meng Zhang, Jiandong Cui

期刊论文

Retraction note to: Industrial bio-based plant aggregates as hygric and insulating construction materials

Yunhong Jiang, Mike Lawrence, Meng Zhang, Jiandong Cui

期刊论文

兴建年产一千吨电子级多晶硅工厂的思考

梁骏吾

期刊论文

Chloride diffusion in concrete with carbonated recycled coarse aggregates under biaxial compression

期刊论文

Laboratory assessment of Alaska aggregates using Micro-Deval test

Jenny LIU,Sheng ZHAO,Anthony MULLIN

期刊论文

A thermoelectric generator and water-cooling assisted high conversion efficiency polycrystalline silicon

Zekun LIU, Shuang YUAN, Yi YUAN, Guojian LI, Qiang WANG

期刊论文

Effects of coarse and fine aggregates on long-term mechanical properties of sea sand recycled aggregate

期刊论文

电子级多晶硅的生产工艺

梁骏吾

期刊论文

Microprofiles of activated sludge aggregates using microelectrodes in completely autotrophic nitrogen

Yongtao LV,Xuan CHEN,Lei WANG,Kai JU,Xiaoqiang CHEN,Rui MIAO,Xudong WANG

期刊论文

Study on micro-texture and skid resistance of aggregate during polishing

Zhenyu QIAN, Lingjian MENG

期刊论文

Ultimate bearing capacity of strip footing resting on clay soil mixed with tire-derived aggregates

期刊论文

Destructive and non-destructive evaluation of concrete for optimum sand to aggregate volume ratio

期刊论文