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Relationships of nitrous oxide fluxes with water quality parameters in free water surface constructed

Juan WU, Jian ZHANG, Wenlin JIA, Huijun XIE, Bo ZHANG

《环境科学与工程前沿(英文)》 2009年 第3卷 第2期   页码 241-247 doi: 10.1007/s11783-009-0023-6

摘要: The effects of chemical oxygen demand (COD) concentration in the influent on nitrous oxide (N O) emissions, together with the relationships between N O and water quality parameters in free water surface constructed wetlands, were investigated with laboratory-scale systems. N O emission and purification performance of wastewater were very strongly dependent on COD concentration in the influent, and the total N O emission in the system with middle COD influent concentration was the least. The relationships between N O and the chemical and physical water quality variables were studied by using principal component scores in multiple linear regression analysis to predict N O flux. The multiple linear regression model against principal components indicated that different water parameters affected N O flux with different COD concentrations in the influent, but nitrate nitrogen affected N O flux in all systems.

关键词: free water surface constructed wetland     nitrous oxide emission     water quality parameter     principal component analysis     multiple linear regression    

Advances in polishing of internal structures on parts made by laser-based powder bed fusion

《机械工程前沿(英文)》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0724-0

摘要: The internal structures of metallic products are important in realizing functional applications. Considering the manufacturing of inner structures, laser-based powder bed fusion (L-PBF) is an attractive approach because its layering principle enables the fabrication of parts with customized interior structures. However, the inferior surface quality of L-PBF components hinders its productization progress seriously. In this article, process, basic forms, and applications relevant to L-PBF internal structures are reviewed comprehensively. The causes of poor surface quality and differences in the microstructure and property of the surface features of L-PBF inner structures are presented to provide a perspective of their surface characteristics. Various polishing technologies for L-PBF components with inner structures are presented, whereas their strengths and weaknesses are summarized along with a discussion on the challenges and prospects for improving the interior surface quality of L-PBF parts.

关键词: laser-based powder bed fusion     polishing     internal structures     surface quality     surface features     post process     additive manufacturing    

Effects of taping on grinding quality of silicon wafers in backgrinding

Zhigang DONG, Qian ZHANG, Haijun LIU, Renke KANG, Shang GAO

《机械工程前沿(英文)》 2021年 第16卷 第3期   页码 559-569 doi: 10.1007/s11465-020-0624-0

摘要: Taping is often used to protect patterned wafers and reduce fragmentation during backgrinding of silicon wafers. Grinding experiments using coarse and fine resin-bond diamond grinding wheels were performed on silicon wafers with tapes of different thicknesses to investigate the effects of taping on peak-to-valley (PV), surface roughness, and subsurface damage of silicon wafers after grinding. Results showed that taping in backgrinding could provide effective protection for ground wafers from breakage. However, the PV value, surface roughness, and subsurface damage of silicon wafers with taping deteriorated compared with those without taping although the deterioration extents were very limited. The PV value of silicon wafers with taping decreased with increasing mesh size of the grinding wheel and the final thickness. The surface roughness and subsurface damage of silicon wafers with taping decreased with increasing mesh size of grinding wheel but was not affected by removal thickness. We hope the experimental finding could help fully understand the role of taping in backgrinding.

关键词: taping     silicon wafer     backgrinding     subsurface damage     surface roughness    

硅及硅基半导体材料中杂质缺陷和表面的研究

屠海令

《中国工程科学》 2000年 第2卷 第1期   页码 7-17

摘要:

随着超大规模集成电路设计线宽向深亚微米级(<0.5μm)和亚四分之一微米级(<0.25μm)发展,对半导体硅片及其它硅基材料的质量要求越来越高,研究上述材料中各种杂质的行为,控制缺陷类型及数量,提高晶体完整性,降低表面污染和采用缺陷工程的方法改善材料质量显得尤为重要。文章阐述了深亚微米级和亚四分之一微米级集成电路用大直径硅材料中铁、铜金属和氧、氢、氮非金属杂质元素的行为,点缺陷及其衍生缺陷的本质与控制方法,硅片表面形貌、表面污染与检测方法的研究热点。同时还介绍了外延硅、锗硅及绝缘体上硅(SOI)等硅基材料的特性、制备及工艺技术发展趋势,展望了跨世纪期间硅及硅基材料产业发展的技术经济前景。

关键词: 硅片     硅外延片     锗硅     绝缘体上硅     杂质行为     缺陷控制     表面质量    

零件加工质量(尺寸和表面粗糙度)在线检测技术研究

陈爱弟,王信义

《中国工程科学》 2000年 第2卷 第12期   页码 73-77

摘要:

文章研究零件加工质量在线检测的方法和关键技术。在分析在线检测工件尺寸和表面粗糙度检测方法及特点的基础上,建立检测工件尺寸的神经网络和检测表面粗糙度的模糊神经网络,并且建立了零件加工质量在线检测系统。实验表明该方法能够正确地实时检测工件的尺寸变化和工件表面粗糙度。

关键词: 在线检测     神经网络     模糊神经网络     尺寸精度     表面粗糙度    

Dimethicone-aided laser cutting of solar rolled glass

Wenyuan LI, Guojun ZHANG, Long CHEN, Yu HUANG, Youmin RONG, Zhangrui GAO

《机械工程前沿(英文)》 2021年 第16卷 第1期   页码 111-121 doi: 10.1007/s11465-020-0615-1

摘要: Solar rolled glass, with one micro-structure surface and another roughness surface, can cause diffuse refraction of the focused laser spot, and this phenomenon restricts the application of laser manufacturing. In this study, laser cutting of solar rolled glass with a thickness of 2.5 mm was successfully achieved with the help of dimethicone to ensure laser focusing. Dimethicone was coated on the top surface of the rolled glass processing zone, and a bottom–up multilayer increment with the spiral line was applied to control the cutting path. Different viscosity values of dimethicone were considered. Results showed that surface quality increased as the viscosity increased until a certain threshold was reached; afterward, the surface quality decreased or directly caused the cutting to fail. The minimum surface roughness (3.26 µm) of the processed surface (chipping: Width≤113.64 µm, area 215199 µm ) was obtained when the dimethicone viscosity and laser pulse frequency were 1000 mm /s and 43 kHz (power 25.4 W), respectively. The micro-defects on the processed surface were few, and the edge chipping width and depth of the laser processed surface were small.

关键词: laser cutting     solar rolled glass     dimethicone     viscosity     surface quality    

From total quality management to Quality 4.0: A systematic literature review and future research agenda

《工程管理前沿(英文)》 2023年 第10卷 第2期   页码 191-205 doi: 10.1007/s42524-022-0243-z

摘要: Quality 4.0 is an emerging concept that has been increasingly appreciated because of the intensification of competition, continually changing customer requirements and technological evolution. It deals with aligning quality management practices with the emergent capabilities of Industry 4.0 to improve cost, time, and efficiency and increase product quality. This article aims to comprehensively review extant studies related to Quality 4.0 to uncover current research trends, distil key research topics, and identify areas for future research. Thus, 46 journal articles extracted from the Scopus database from 2017 to 2022 were collected and reviewed. A descriptive analysis was first performed according to the year-wise publication, sources of publication, and research methods. Then, the selected articles were analyzed and classified according to four research themes: Quality 4.0 concept, Quality 4.0 implementation, quality management in Quality 4.0, and Quality 4.0 model and application. By extracting the literature review findings, we identify the Quality 4.0 definitions and features, develop the quality curve theory, and highlight future research opportunities. This study supports practitioners, managers, and academicians in effectively recognizing and applying Quality 4.0 to enhance customer satisfaction, achieve innovation enterprise efficiency, and increase organizational competitiveness in the era of Industry 4.0.

关键词: quality management     Quality 4.0     Industry 4.0     literature review     predictive quality    

High-quality industrial n-type silicon wafers with an efficiency of over 23% for Si heterojunction solar

Fanying MENG,Jinning LIU,Leilei SHEN,Jianhua SHI,Anjun HAN,Liping ZHANG,Yucheng LIU,Jian YU,Junkai ZHANG,Rui ZHOU,Zhengxin LIU

《能源前沿(英文)》 2017年 第11卷 第1期   页码 78-84 doi: 10.1007/s11708-016-0435-5

摘要: n-type CZ-Si wafers featuring longer minority carrier lifetime and higher tolerance of certain metal contamination can offer one of the best Si-based solar cells. In this study, Si heterojuction (SHJ) solar cells which was fabricated with different wafers in the top, middle and tail positions of the ingot, exhibited a stable high efficiency of>22% in spite of the various profiles of the resistivity and lifetime, which demonstrated the high material utilization of n-type ingot. In addition, for effectively converting the sunlight into electrical power, the pyramid size, pyramid density and roughness of surface of the Cz-Si wafer were investigated by scanning electron microscope (SEM) and transmission electron microscope (TEM). Furthermore, the dependence of SHJ solar cell open-circuit voltage on the surface topography was discussed, which indicated that the uniformity of surface pyramid helps to improve the open-circuit voltage and conversion efficiency. Moreover, the simulation revealed that the highest efficiency of the SHJ solar cell could be achieved by the wafer with a thickness of 100 µm. Fortunately, over 23% of the conversion efficiency of the SHJ solar cell with a wafer thickness of 100 µm was obtained based on the systematic optimization of cell fabrication process in the pilot production line. Evidently, the large availability of both n-type ingot and thinner wafer strongly supported the lower cost fabrication of high efficiency SHJ solar cell.

关键词: n-type Cz-Si     thinner wafer     surface texture     high efficiency     SHJ solar cell    

Ceramic water filter for point-of-use water treatment in developing countries: Principles, challenges and opportunities

Haiyan Yang, Shangping Xu, Derek E. Chitwood, Yin Wang

《环境科学与工程前沿(英文)》 2020年 第14卷 第5期 doi: 10.1007/s11783-020-1254-9

摘要: • CWF is a sustainable POU water treatment method for developing areas. • CWF manufacturing process is critical for its filtration performance. • Simultaneous increase of flow rate and pathogen removal is a challenge. • Control of pore size distribution holds promises to improve CWF efficiency. • Novel coatings of CWFs are a promising method to improve contaminant removal. Drinking water source contamination poses a great threat to human health in developing countries. Point-of-use (POU) water treatment techniques, which improve drinking water quality at the household level, offer an affordable and convenient way to obtain safe drinking water and thus can reduce the outbreaks of waterborne diseases. Ceramic water filters (CWFs), fabricated from locally sourced materials and manufactured by local labor, are one of the most socially acceptable POU water treatment technologies because of their effectiveness, low-cost and ease of use. This review concisely summarizes the critical factors that influence the performance of CWFs, including (1) CWF manufacturing process (raw material selection, firing process, silver impregnation), and (2) source water quality. Then, an in-depth discussion is presented with emphasis on key research efforts to address two major challenges of conventional CWFs, including (1) simultaneous increase of filter flow rate and bacterial removal efficiency, and (2) removal of various concerning pollutants, such as viruses and metal(loid)s. To promote the application of CWFs, future research directions can focus on: (1) investigation of pore size distribution and pore structure to achieve higher flow rates and effective pathogen removal by elucidating pathogen transport in porous ceramic and adjusting manufacture parameters; and (2) exploration of new surface modification approaches with enhanced interaction between a variety of contaminants and ceramic surfaces.

关键词: Point-of-use water treatment     Ceramic water filter     Bacterial removal     Surface modification     Water quality    

Analysis and comparison of laser cutting performance of solar float glass with different scanning modes

Wenyuan LI, Yu HUANG, Youmin RONG, Long CHEN, Guojun ZHANG, Zhangrui GAO

《机械工程前沿(英文)》 2021年 第16卷 第1期   页码 97-110 doi: 10.1007/s11465-020-0600-8

摘要: Cutting quality and efficiency have always been important indicators of glass laser cutting. Laser scanning modes have two kinds, namely, the spiral and concentric circle scanning modes. These modes can achieve high-performance hole cutting of thick solar float glass using a 532-nm nanosecond laser. The mechanism of the glass laser cutting under these two different scanning modes has been described. Several experiments are conducted to explore the effect of machining parameters on cutting efficiency and quality under these two scanning modes. Results indicate that compared with the spiral scanning mode, the minimum area of edge chipping (218340 µm ) and the minimum Ra (3.01 µm) in the concentric circle scanning mode are reduced by 9.4% and 16.4% respectively. Moreover, the best cutting efficiency scanning mode is 14.2% faster than that in the spiral scanning mode. The best parameter combination for the concentric circle scanning mode is as follows: Scanning speed: 2200 mm/s, number of inner circles: 6, and circle spacing: 0.05 mm. This parameter combination reduces the chipping area and sidewall surface roughness by 8.8% and 9.6% respectively at the same cutting efficiency compared with the best spiral processing parameters. The range of glass processing that can be achieved in the concentric circle scanning mode is wider than that in the spiral counterpart. The analyses of surface topography, white spots, microstructures, and sidewall surface element composition are also performed. The study concluded that the concentric circle scanning mode shows evident advantages in the performance of solar float glass hole cutting.

关键词: laser cutting     solar float glass     scanning mode     surface quality     cutting efficiency    

Research and establishment of enterprise quality metadata standard

SONG Han, LI Jie, ZHANG Genbao

《机械工程前沿(英文)》 2008年 第3卷 第1期   页码 106-110 doi: 10.1007/s11465-008-0019-0

摘要: Enabling quality managers to utilize and manage quality data efficiently under modern quality management circumstances is a primary issue for improving enterprise quality management. A concept of quality metadata is proposed in this paper, which can help quality managers gain a deeper understanding of various features of quality data and establish a more stable foundation for further use and management of such data. The procedure of establishing quality metadata standards is emphasized in the paper, and the content structure and description scheme are given. Finally, a summary is made and future work is prospected.

关键词: enterprise quality     foundation     description     quality management     primary    

Foxtail millet: nutritional and eating quality, and prospects for genetic improvement

Lu HE,Bin ZHANG,Xingchun WANG,Hongying LI,Yuanhuai HAN

《农业科学与工程前沿(英文)》 2015年 第2卷 第2期   页码 124-133 doi: 10.15302/J-FASE-2015054

摘要: Foxtail millet is a minor yet important crop in some areas of the world, particularly northern China. It has strong adaptability to abiotic stresses, especially drought, and poor soil. It also has high nutritional value. Foxtail millet is rich in essential amino acids, fatty acids and minerals, and is considered to be one of the most digestible and non-allergenic grains available and has significant importance for human health. Given foxtail millet’s ability to adapt to abiotic stresses associated with climate change, it is more important than ever to develop breeding strategies that facilitate the increasing demand for high quality grain that better satisfies consumers. Here we review research on foxtail millet quality evaluation, appearance, cooking and eating quality at the phenotypic level. We review analysis of the main nutrients in foxtail millet, their relationships and the biochemical and genetic factors affecting their accumulation. In addition, we review past progress in breeding this regionally important crop, outline current status of breeding of foxtail millet, and make suggestions to improve grain quality.

关键词: foxtail millet     grain quality     quality evaluation     breeding for quality    

A review of hydrological/water-quality models

Liangliang GAO,Daoliang LI

《农业科学与工程前沿(英文)》 2014年 第1卷 第4期   页码 267-276 doi: 10.15302/J-FASE-2014041

摘要: Water quality models are important in predicting the changes in surface water quality for environmental management. A range of water quality models are wildly used, but every model has its advantages and limitations for specific situations. The aim of this review is to provide a guide to researcher for selecting a suitable water quality model. Eight well known water quality models were selected for this review: SWAT, WASP, QUALs, MIKE 11, HSPF, CE-QUAL-W2, ELCOM-CAEDYM and EFDC. Each model is described according to its intended use, development, simulation elements, basic principles and applicability (e.g., for rivers, lakes, and reservoirs and estuaries). Currently, the most important trends for future model development are: (1) combination models—individual models cannot completely solve the complex situations so combined models are needed to obtain the most appropriate results, (2) application of artificial intelligence and mechanistic models combined with non-mechanistic models will provide more accurate results because of the realistic parameters derived from non-mechanistic models, and (3) integration with remote sensing, geographical information and global position systems (3S) —3S can solve problems requiring large amounts of data.

关键词: water quality models     applications     future trends    

Evaluation of ICUs and weight of quality control indicators: an exploratory study based on Chinese ICUquality data from 2015 to 2020

《医学前沿(英文)》 2023年 第17卷 第4期   页码 675-684 doi: 10.1007/s11684-022-0970-x

摘要: This study aimed to explore key quality control factors that affected the prognosis of intensive care unit (ICU) patients in Chinese mainland over six years (2015−2020). The data for this study were from 31 provincial and municipal hospitals (3425 hospital ICUs) and included 2 110 685 ICU patients, for a total of 27 607 376 ICU hospitalization days. We found that 15 initially established quality control indicators were good predictors of patient prognosis, including percentage of ICU patients out of all inpatients (%), percentage of ICU bed occupancy of total inpatient bed occupancy (%), percentage of all ICU inpatients with an APACHE II score ≥15 (%), three-hour (surviving sepsis campaign) SSC bundle compliance (%), six-hour SSC bundle compliance (%), rate of microbe detection before antibiotics (%), percentage of drug deep venous thrombosis (DVT) prophylaxis (%), percentage of unplanned endotracheal extubations (%), percentage of patients reintubated within 48 hours (%), unplanned transfers to the ICU (%), 48-h ICU readmission rate (%), ventilator associated pneumonia (VAP) (per 1000 ventilator days), catheter related blood stream infection (CRBSI) (per 1000 catheter days), catheter-associated urinary tract infections (CAUTI) (per 1000 catheter days), in-hospital mortality (%). When exploratory factor analysis was applied, the 15 indicators were divided into 6 core elements that varied in weight regarding quality evaluation: nosocomial infection management (21.35%), compliance with the Surviving Sepsis Campaign guidelines (17.97%), ICU resources (17.46%), airway management (15.53%), prevention of deep-vein thrombosis (14.07%), and severity of patient condition (13.61%). Based on the different weights of the core elements associated with the 15 indicators, we developed an integrated quality scoring system defined as F score=21.35%×nosocomial infection management + 17.97%×compliance with SSC guidelines + 17.46%×ICU resources + 15.53%×airway management + 14.07%×DVT prevention + 13.61%×severity of patient condition. This evidence-based quality scoring system will help in assessing the key elements of quality management and establish a foundation for further optimization of the quality control indicator system.

关键词: critical care medicine     quality control     evaluation     exploratory factor analysis (EFA) model    

标题 作者 时间 类型 操作

Relationships of nitrous oxide fluxes with water quality parameters in free water surface constructed

Juan WU, Jian ZHANG, Wenlin JIA, Huijun XIE, Bo ZHANG

期刊论文

Advances in polishing of internal structures on parts made by laser-based powder bed fusion

期刊论文

Effects of taping on grinding quality of silicon wafers in backgrinding

Zhigang DONG, Qian ZHANG, Haijun LIU, Renke KANG, Shang GAO

期刊论文

硅及硅基半导体材料中杂质缺陷和表面的研究

屠海令

期刊论文

零件加工质量(尺寸和表面粗糙度)在线检测技术研究

陈爱弟,王信义

期刊论文

Dimethicone-aided laser cutting of solar rolled glass

Wenyuan LI, Guojun ZHANG, Long CHEN, Yu HUANG, Youmin RONG, Zhangrui GAO

期刊论文

From total quality management to Quality 4.0: A systematic literature review and future research agenda

期刊论文

High-quality industrial n-type silicon wafers with an efficiency of over 23% for Si heterojunction solar

Fanying MENG,Jinning LIU,Leilei SHEN,Jianhua SHI,Anjun HAN,Liping ZHANG,Yucheng LIU,Jian YU,Junkai ZHANG,Rui ZHOU,Zhengxin LIU

期刊论文

吴丰昌:我国地表水环境质量标准制定修订研究(2019年10月17日)

吴丰昌(院士)

2021年01月20日

会议视频

Ceramic water filter for point-of-use water treatment in developing countries: Principles, challenges and opportunities

Haiyan Yang, Shangping Xu, Derek E. Chitwood, Yin Wang

期刊论文

Analysis and comparison of laser cutting performance of solar float glass with different scanning modes

Wenyuan LI, Yu HUANG, Youmin RONG, Long CHEN, Guojun ZHANG, Zhangrui GAO

期刊论文

Research and establishment of enterprise quality metadata standard

SONG Han, LI Jie, ZHANG Genbao

期刊论文

Foxtail millet: nutritional and eating quality, and prospects for genetic improvement

Lu HE,Bin ZHANG,Xingchun WANG,Hongying LI,Yuanhuai HAN

期刊论文

A review of hydrological/water-quality models

Liangliang GAO,Daoliang LI

期刊论文

Evaluation of ICUs and weight of quality control indicators: an exploratory study based on Chinese ICUquality data from 2015 to 2020

期刊论文