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Ultrafiltration with in-line coagulation for the removal of natural humic acid and membrane fouling mechanism

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Journal of Environmental Sciences 2006年第5期18卷 880-884页

作者： wang Jin wang xiao-chang Department of Municipal and Environmental Engineering Beijing Jiaotong University Beijing 100044 China School of Environmental and Municipal Engineering Xi＇an University of Architecture and Technology Xi＇an 710055 China

Experimental and theoretical analysis were made on the natural humic acid removal and the membrane fouling of ultrafiltration （UF） with in-line coagulation. The results showed dissolved organic carbon （DOC） and UV254 removals by the UF with in-line coagulation at pH 7 were increased from 28% to 53% and 40% to 78% in comparison with direct UF treatment respectively. At the same time, the analysis of high performance liquid chromatography showed that UF with coagulation had significant improvement of removal of humic acid with molecular weights less than 6000 Da in particular. Compared to direct UF, the in-line coagulation UF also kept more constant permeate flux and very slight increase oftransmembrane pressure during a filtration circle. Two typical membrane fouling models were used by inducing two coefficients Kc and Kp corresponding to cake filtration model and pore narrowing model respectively. It was found that membrane fouling by pore-narrowing effect was effectively alleviated and that by cake-filtration was much decreased by in-line coagulation. Under the condition of coagulation prior to ultrafiltration at pH 7, the cake layer formed on the membrane surface became thicker, but the membrane filtration resistance was lower than that at pH 5 with the extension of operation time.

关键词： natural humic acid ultrafiltration (UF) in-line coagulation high performance liquid chromatography (HPLC) membrane fouling

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五姿态轮椅设计与试验研究

林产工业 2024年第10期61卷 61-66页

作者：王晓昌罗春阳李作家孙永强王小平王延振北华大学机械工程学院吉林省吉林市132013 南方医科大学南方医院广东广州510515

针对国内的轮椅使用者在室内独立生活中面临的双手控制空间较小以及姿态转换稳定性不佳等问题,本文设计了一种融合五种姿态、具备高稳定性和可靠性的多姿态轮椅。基于人体工程学和可靠性工程学,设计了两种适用于小空间且具备高力矩的传... 详细信息

针对国内的轮椅使用者在室内独立生活中面临的双手控制空间较小以及姿态转换稳定性不佳等问题,本文设计了一种融合五种姿态、具备高稳定性和可靠性的多姿态轮椅。基于人体工程学和可靠性工程学,设计了两种适用于小空间且具备高力矩的传动模块。通过对连杆模块进行运动学分析,验证了机构设计的合理性和稳定性。最后,利用姿态传感器对轮椅的姿态变换稳定性和静态刚度进行了测试。结果表明:该五姿态轮椅能够实现五种姿态的平稳变换,扩大了使用者的双手控制空间,并具备较高的静态刚度,能够满足下肢行动不便者独立生活的需求,提升了其独立生活的能力和生活质量。

关键词：人体工程学多姿态融合运动学高稳定性独立生活

Selective Permeation of CO_2 Through Modified PVSA/PS Composite Membrane

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Chinese Chemical Letters 2006年第2期17卷 277-280页

作者： Ying ZHANG Zhi wang Juan ZHAO Ji xiao wang Shi chang wang Chemical Engineering Research Center School of Chemical Engineering and Technology Tianjin University Tianjin 300072

A new fixed carder membrane material VSA-SA for CO2 separation was prepared through the chemical modification of PVSA. The selective permeation of CO2 through VSA-SA/PS composite membrane was performed with CO2/CH4 system. The VSA-SA/PS composite membranes possess better CO2 permselectivity than PVSA/PS composite membrane. Keywords： Fixed carder membrane, CO2 separation, PVSA, VSA-SA.

关键词： Fixed carder membrane CO2 separation PVSA VSA-SA.

Effect of Waterlogged and Aerobic Incubation on Enzyme Activities in Paddy Soil

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Pedosphere 2006年第4期16卷 532-539页

作者： wang xiao-chang LU Qin Department of Tea Science College of Agriculture and Biotechnology Zhejiang University Hangzhou 31002g （China） Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 （China）

An incubation experiment with soil water content treatments of 0.15 （W1）, 0.20 （W2）, and 0.40 （W3） g g^-1 soil was carried out for two months to investigate the activities of important enzymes involved in C, N, P, and S cycling in a paddy soil from the Taihu Lake region, China, under waterlogged and aerobic conditions. Compared with air-dried soil, waterlogging resulted in a significant decrease （P ≤ 0.05） of fluorescein diacetate （FDA） and /3-D-glucosidase activities, and this effect was enhanced with increasing waterlogging time. Waterlogging also significantly inhibited （P ≤ 0.05） arylsulfatase as well as alkaline and acid phosphatase activities, but did not decrease the activities with the increase in waterlogging time. Short-term waterlogging did not affect urease activity, but prolonged waterlogging decreased it markedly. In contrast, the aerobic incubation （W1 and W2 treatments） significantly increased （P ≤ 0.05） FDA, alkaline phosphatase, and /3-D-glucosidase activities. With aerobic treatments the activities of FDA and alkaline phosphatase increased with incubation time, whereas /3-D-glucosidase activity decreased. A significant difference （P ≤ 0.05） was usually observed between the W1 and W2 treatments for the activities of FDA as well as alkaline and acid phosphatase; however,/3-D-glucosidase and urease were usually not significant （P ≤ 0.05）. No activity differences were observed between waterlogging and aerobic incubation for arylsulfatase and urease.

关键词： aerobic incubation enzyme activity paddy soil waterlogging

Beta-Glucosidase Activity in Paddy Soils of the Taihu Lake Region, China

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Pedosphere 2006年第1期16卷 118-124页

作者： wang xiao-chang LU Qin Department of Tea Science Zhejiang University Hangzhou 310029 （China）. Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 （China）

The profile distribution of β-gulcosidase activity in twelve typical paddy soil profiles with high productivity in the Taihu Lake region of China were investigated. Activities of β-gulcosidase in the plow layers were in the range of 52.68- 137.02μg PNP g^-1 soil h^-1 with a mean of 89.22μg PNP g^-1 soil h^-1. However, most plow layers ranged from 70 to 110 μg PNP g^-1 soil h^-1. The profile distribution of β-gulcosidase activity in the 12 soil profiles decreased rapidly with soil depth, with activity at the 60 cm depth only about 10% of that in the surface layers （0-15 cm or 0-20 cm）. In these soil profiles, β-gulcosidase activity was significantly positively correlated with soll organic carbon and arylsulphatase activity. Meanwhile, a significantly negative correlation was shown between β-gulcosidase activity and soil pH.

关键词： beta-gulcosidase activity profile distribution paddy soil Taihu Lake region

Effect of electrical parameters and slag system on macrostructure of electroslag ingot

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China Foundry 2024年第1期21卷 44-50页

作者： Bing-jie wang Yu wang Meng-jun wang Lei Zhao Li-zhong chang xiao-fang Shi School of Metallurgy engineering Anhui University of TechnologyMa'anshan 243002AnhuiChina

To investigate the influence of electric parameters and slag system on the solidification quality of electroslag ingot during electroslag remelting,different power supply modes,current strengths and remelting slag systems were used to conduct electroslag remelting experiments on 304L austenitic stainless steel,and the macrostructure of electroslag ingots was *** results indicate that the depth of the metal pool decreases with the reduction of remelting frequency in the low frequency power supply *** effects of different power supply modes,such as low-frequency,direct current straight polarity(DCSP),and direct current reverse polarity(DCRP),on reducing the depth of the metal pool increase in that *** reducing the remelting current strength in the same power supply mode,the depth of metal pool is *** compared to the binary slag system of 70%CaF2+30%Al2O3,the ternary slag system of 60%CaF2+20%Al2O3+20%CaO is more effective in reducing the depth of the metal pool during *** the 60%CaF2+20%Al2O3+20%CaO ternary slag system results in a shallower and flatter metal pool,with columnar crystal growth occurring closer to the axial *** effect is observed for both low frequency and direct current(DC)power supply modes.

关键词： electroslag remelting frequency slag system solidification quality

Towards green asphalt materials with lower emission of volatile organic compounds: A review on the release characteristics and its emission reduction additives

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Journal of Road Engineering 2024年第3期4卷 292-317页

作者： Xiwen chang Feng wang Rui Wu Chen wang Yue xiao State Key Laboratory of Silicate Materials for Architectures Wuhan University of TechnologyWuhan 430070China School of Materials Science and Engineering Chang'an UniversityXi'an 710064China Faculty of Civil Engineering and Geosciences Delft University of TechnologyDelft 2628 CNthe Netherlands

Recently, researchers in the road field are focusing on the development of green asphalt materials with loweremission of volatile organic compounds (VOCs). The characterization methodology of asphalt VOCs and theinfluencing factors on VOCs release have always been the basic issue of asphalt VOCs emission reduction *** have proposed a variety of asphalt VOCs characterization methodologies, which also have mutuallyirreplaceable characteristics. Asphalt VOCs volatilization is affected by many factors. In this study, asphalt VOCscharacterization methodologies were summarized, including their advantages, disadvantages, characteristics andapplicable requirements. Subsequently, the influencing factors of VOCs release, such as asphalt types and environment conditions, are summarized to provide theoretical support for the emission reduction research. Theclassification and mechanism of newly-development asphalt VOCs emission reduction materials are reviewed. Thereduction efficiencies are also compared to select better materials and put forward the improvement objective ofnew materials and new processes. In addition, the prospects about development of VOCs release mechanism ofasphalt materials during the full life cycle and feasibility research of high-efficiency composite emission reductionmaterials in the future were put forward.

关键词： Asphalt VOCs Volatile organic compounds Green asphalt materials Reduction efficiency Hazardous emission

Difference in Selenium Accumulation in Shoots of Two Rice Cultivars

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Pedosphere 2006年第5期16卷 646-653页

作者： ZHANG Lian-He SHI Wei-Ming wang xiao-chang State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of SciencesNanjing 210008 （China） Agricultural College Henan University of Science and Technology Luoyang 471003 （China） Department of Tea Science Zhejiang University Hangzhou 310029 （China）

Two japonica rice （Oryza sativa L.） cultivars, Xiushui 48 and S. Andrea, differing in their ability to accumulate Se in the grain （as high as a three-fold difference）, were compared for selenium （Se） accumulation in their shoots when their growth media was supplied with different forms of Se. Results indicated that when treated with 0.25μmol L^-1 Na2SeO3, Xiushui 48 accumulation of Se in the shoots was significantly more rapid （P〈0.05） than S. Andrea, probably because of greater Se uptake and transport in Xiushui 48. Xiushui 48 rice seedlings had a higher shoot-Se accumulation rate and absorbed selenocysteine （Se-Cys） more rapidly than S. Andrea seedlings. However, when treated with Se as 0.25μmol L^-1 selenomethionine （Se-Met）, the S. Andrea seedlings＇ accumulation rate was significantly greater （P〈0.05） than that of Xiushui 48. Possibly, the high Se accumulation rate of Xiushui 48 seedling shoots compared to S. Andrea shoots was the result of a higher capacity of Xiushui 48 to transform selenite to organic Se compounds and a higher selenite uptake rate.

关键词： rice cultivars Se accumulation selenite transport uptake rate

Al-doped ZnO/WO_(3) heterostructure films prepared by magnetron sputtering for isopropanol sensors

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Rare Metals 2024年第1期43卷 247-256页

作者： Wei-Xiang Gao Xue-Ting chang xiao-Jie Zhu Jun-Feng Li Ying-chang Jiang Dong-Sheng wang Chuan-xiao Yang Shi-Bin Sun College of Logistics Engineering Shanghai Maritime UniversityShanghai 201306China College of Ocean Science and Engineering Shanghai Maritime UniversityShanghai 201306China Institute of Logistics Science and Engineering Shanghai Maritime UniversityShanghai 201306China

Metal oxide semiconductors(MOSs) are ideal sensing materials for detecting volatile organic compounds due to their low cost, diversity, high stability, and ease of production. However, it remains a grand challenge to develop the MOSs-based gas sensors for sensing isopropanol with desired performance via a simple, effective,and controllable method. Herein, we reported the preparation of the Al-doped Zn O(AZO)/WO_(3) heterostructure films by directly depositing the AZO coating onto the WO_(3) coating using a strategy of magnetron sputtering. The AZO/WO_(3) heterostructure films were constructed by numbers of irregular nanoparticles that were interconnected with each other. The AZO/WO_(3) heterostructure films-based gas sensors exhibited excellent isopropanolsensing performance with high response, promising selectivity, low detection limit, fast response rate, wide detection range, and ideal reproducibility. The promising isopropanol-sensing performance of the AZO/WO_(3) heterostructure films arises mainly from their high uniformity, unique microstructures with high surface roughness,and the construction of the heterostructure between the AZO and WO_(3) coatings. This work provides a versatile approach to prepare the MOSs-based heterostructure films for assembling the gas sensors.

关键词： Metal oxide semiconductors Gas sensors Aldoped ZnO/WO_(3) Heterostructure films Isopropanol Magnetron sputtering