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Design Method and Numerical Control Machining Principle for an Arbitrary n-polygon Noncircular Section

WU Yi-jie, LENG Hong-bin

《机械工程前沿(英文)》 2006年 第1卷 第1期   页码 71-75 doi: 10.1007/s11465-005-0005-8

摘要:

By analyzing the structure characteristics of arbitrary n-polygon noncircular sections, mathematical formulas among the characteristic parameters were set up, and a theorem for designing this kind of sections was deduced by mathematical induction method. Based on the mechanistic transmission principle, the control theorems for the numerical control (NC) grinding of arbitrary n-polygon noncircular sections and the control model for the multicoordinate motion were built. A feed rate selfadjusting method was proposed to uniform the grinding speed with the changes of sectional curvature. Then, an NC machine tool for grinding n-polygon noncircular sections was developed. The test results of the grinded parts showed that the section profiles accorded with the design demands: the roughness was less than 0.32 ?m and the dimensional accuracy was within 8 ?m. The results prove that the proposed theorems and method can effectively direct the design and manufacture of the polygonal noncircular connection.

关键词: manufacture     multicoordinate     characteristic     polygonal noncircular     mechanistic transmission    

Evaluation of 1,4-naphthoquinone derivatives as antibacterial agents: activity and mechanistic studies

《环境科学与工程前沿(英文)》 2023年 第17卷 第3期 doi: 10.1007/s11783-023-1631-2

摘要:

● All 1,4-naphthoquinone hybrids exhibited significant antimicrobial activity.

关键词: 1     4-naphthoquinone derivatives     Antibacterial     Action mechanism     RecA    

Mechanistic insights into the selective photocatalytic degradation of dyes over TiO/ZSM-11

《环境科学与工程前沿(英文)》 2023年 第17卷 第8期 doi: 10.1007/s11783-023-1701-5

摘要:

● TiO2/ZSM-11 was prepared by a facile solid state dispersion method.

关键词: Selective dye degradation     Photocatalysis     TiO2     ZSM-11     Chemisorption    

Recent advances in cycloaddition of CO with epoxides: halogen-free catalysis and mechanistic insights

《化学科学与工程前沿(英文)》 2023年 第17卷 第12期   页码 1879-1894 doi: 10.1007/s11705-023-2354-4

摘要: The atom-economical cycloaddition of CO2 with epoxides to synthesize cyclic carbonates is a promising route for valuable utilization of CO2. Halogenide such as alkali metal halides and quaternary ammonium salt have been developed as the efficient catalysts. However, the spilled halogen causes equipment corrosion and affects the product purity. To address these concerns, the halogen-free cycloaddition of CO2 with epoxides has always been desired. In this review, we systematically discussed the halogen-free catalysis for cycloaddition of CO2 with epoxides from the mechanistic insights, aiming to promote the development of efficient halogen-free catalysts. Two types of catalysts, i.e., alternatives of halogen nucleophiles for epoxide activation, and bifunctional catalysts with Lewis acid-base sites for synergistic activation of CO2 and epoxides are summarized and emphasized. Specially, metal oxides as the potential halogen-free catalysts are highlighted due to their flexible acid-base sites for synergistic activation of CO2 and epoxides, facile preparation, and low cost.

关键词: carbon dioxide     halogen-free catalysis     cyclic carbonate     mechanistic insight    

Improved film evaporator for mechanistic understanding of microwave-induced separation process

Xin Gao, Dandan Shu, Xingang Li, Hong Li

《化学科学与工程前沿(英文)》 2019年 第13卷 第4期   页码 759-771 doi: 10.1007/s11705-019-1816-1

摘要: Microwave-induced film evaporation separation process has been reported recently to separate the polar/nonpolar mixture. However, the efficiency of the separation is still too low for practical applications, which requires further enhancement via different strategies such as optimization design of evaporator structure. In addition the depth understanding of the separation mechanisms is great importance for better utilization of the microwave-induced separation process. To carry out these investigations, a novel microwave-induced falling film evaporation instrument was developed in this paper. The improvement of the enhancement effect of microwave-induced separation was observed based on the improved film evaporator. The systematic experiments on microwave-induced separation with different binary azeotropic mixtures (ethanol-ethyl acetate system and dimethyl carbonate (DMC)-H O system) were conducted based on the new evaporator. For the ethanol-ethyl acetate system, microwave irradiation shift the direction of evaporation separation at higher ethanol content in the starting liquid mixture. Moreover, for DMC-H O system microwave-induced separation process broke through the limitations of the traditional distillation process. The results clearly demonstrated the microwave-induced evaporation separation process could be commendably applied to the separation of binary azeotrope with different dielectric properties. Effects of operating parameters are also investigated to trigger further mechanism understanding on the microwave-induced separation process.

关键词: process intensification     microwave     falling film evaporation     separation     azeotrope    

doping boosted low-temperature NH-SCR activity of FeTiO catalyst: A microstructure analysis and reaction mechanistic

《环境科学与工程前沿(英文)》 2022年 第16卷 第5期 doi: 10.1007/s11783-022-1539-2

摘要:

• CeO2 doping significantly improved low-temperature NH3-SCR activity on FeTiOx.

关键词: NH3-SCR     CeO2 doping     Low-temperature NOx removal     Improved redox property     In situ XAFS analysis    

EDTA-intercalated layered double hydroxide for enhanced recovery of Cr(VI) and Congo red: Adsorptive and mechanistic

Jing Li, Haiqin Yu, Xue Zhang, Rixin Zhu, Liangguo Yan

《环境科学与工程前沿(英文)》 2020年 第14卷 第3期 doi: 10.1007/s11783-020-1229-x

摘要: Functional groups of AM and EDTA in composite increased removal of Cr(VI) and CR. Removal process reached equilibrium within 30 min and was minimally affected by pH. Elimination of Cr(VI) was promoted by coexisting CR. Adsorption process of CR was less influenced by the presence of Cr(VI). Mechanisms were electrostatic attraction, surface complexation and anion exchange. We prepared ethylenediaminetetraacetic acid (EDTA)-intercalated MgAl-layered double hydroxide (LDH-EDTA), then grafted acrylamide (AM) to the LDH-EDTA by a cross-linking method to yield a LDH-EDTA-AM composite; we then evaluated its adsorptive ability for Congo red (CR) and hexavalent chromium (Cr(VI)) in single and binary adsorption systems. The adsorption process on LDH-EDTA-AM for CR and Cr(VI) achieved equilibrium quickly, and the removal efficiencies were minimally affected by initial pH. The maximum uptake quantities of CR and Cr(VI) on LDH-EDTA-AM were 632.9 and 48.47 mg/g, respectively. In mixed systems, chromate removal was stimulated by the presence of CR, while the adsorption efficiency of CR was almost not influenced by coexisting Cr(VI). The mechanisms involved electrostatic attraction, surface complexation, and anion exchange for the adsorption of both hazardous pollutants. In the Cr(VI) adsorption process, reduction also took place. The removal efficiencies in real contaminated water were all higher than those in the laboratory solutions.

关键词: Chromate     Dye adsorption     Simultaneous removal     Cross-linking method     Amino functionalization    

Choosing configurations of transmission line tower grounding by back flashover probability value

Dmitry KUKLIN

《能源前沿(英文)》 2016年 第10卷 第2期   页码 213-226 doi: 10.1007/s11708-016-0398-6

摘要: There is a considerable number of works devoted to electrical characteristics of grounding. These characteristics are important in general. However, in application to grounding of transmission line towers they are not enough to determine what grounding construction is preferable in some particular case, because these characteristics are calculated or measured apart from the grounded object, and only limited number of current (or voltage) source waveforms is used. This paper indicates reasons in favor of the fact that to choose the optimum design of grounding, the calculation model should include the tower as it is. The probability of back flashover, which provides both qualitative and quantitative estimate of the grounding structure efficiency, can be taken as the criterion for the grounding design. The insulation flashover probability is calculated on the basis of engineering method, which evaluates breakdown strength of insulation for nonstandard waveshapes, and probability data on lightning currents. Different approaches are examined for identifying the back flashover probability, as not only amplitudes but also other parameters can be taken into account. Finite-difference time-domain method is used for calculations of transients. It is found that lightning current waveform can greatly influence calculated back flashover probability value.

关键词: grounding     transmission line tower     back flashover probability     FDTD method    

Performance and mechanistic study on electrocoagulation process for municipal wastewater treatment based

Zhenlian Qi, Shijie You, Ranbin Liu, C. Joon Chuah

《环境科学与工程前沿(英文)》 2020年 第14卷 第3期 doi: 10.1007/s11783-020-1215-3

摘要: EC modified with BPEs enhances pollutant removal and reduce energy consumption. Increasing BPE number cannot increase flocculants yield exponentially. Simulations help to predict the distribution of electrochemical reactions on BPEs. The design of electrodes is crucial to electrocoagulation process (EC), specifically, with respect to pollutant removal and energy consumption. During EC, the mechanisms for interaction between different electrode arrangement and electrode reactions remain unclear. This work presents an integrated EC process based on horizontal bipolar electrodes (BPEs). In the electrochemical cell, the graphite plates are used as driving cathode while either Fe or Al plates serves as driving anode and BPEs. The BPEs are placed horizontally between the driving electrodes. For municipal wastewater treatment, the pollutant removal efficiency and energy consumption in different configurations of two-dimension electrocoagulation (2D-EC) system with horizontal BPEs were investigated. The removal efficiency of turbidity, total phosphorus and total organic carbon increased significantly with the number of BPEs. Noted that the energy consumption for TP removal decreased by 75.2% with Fe driving anode and 81.5% with Al driving anode than those of 2D-EC, respectively. In addition, the physical field simulation suggested the distributions of potential and current in electrolyte and that of induced charge density on BPE surface. This work provides a visual theoretical guidance to predict the distribution of reactions on BPEs for enhanced pollutant removal and energy saving based on electrocoagulation process for municipal wastewater treatment.

关键词: Electrocoagulation     Bipolar electrodes     Municipal wastewater     Simulations    

Cadmium removal mechanistic comparison of three Fe-based nanomaterials: Water-chemistry and roles of

《环境科学与工程前沿(英文)》 2022年 第16卷 第12期 doi: 10.1007/s11783-022-1586-8

摘要:

● nZVI, S-nZVI, and nFeS were systematically compared for Cd(II) removal.

关键词: Nano zero valent iron     Sulfided zero valent iron     FeS     Cd(II) immobilization     Fe dissolution    

Recent transmission of Mycobacterium tuberculosis in China: the implication of molecular epidemiology

null

《医学前沿(英文)》 2018年 第12卷 第1期   页码 76-83 doi: 10.1007/s11684-017-0609-5

摘要:

Tuberculosis (TB) has remained an ongoing concern in China. The national scale-up of the Directly Observed Treatment, Short Course (DOTS) program has accelerated the fight against TB in China. Nevertheless, many challenges still remain, including the spread of drug-resistant strains, high disease burden in rural areas, and enormous rural-to-urban migrations. Whether incident active TB represents recent transmission or endogenous reactivation has helped to prioritize the strategies for TB control. Evidence from molecular epidemiology studies has delineated the recent transmission of ( ) strains in many settings. However, the transmission patterns of TB in most areas of China are still not clear. Studies carried out to date could not capture the real burden of recent transmission of the disease in China because of the retrospective study design, incomplete sampling, and use of low-resolution genotyping methods. We reviewed the implementations of molecular epidemiology of TB in China, the estimated disease burden due to recent transmission of strains, the primary transmission of drug-resistant TB, and the evaluation of a feasible genotyping method of strains in circulation.

关键词: tuberculosis     recent transmission     molecular epidemiology     China    

Antibiotic resistome mostly relates to bacterial taxonomy along a suburban transmission chain

《环境科学与工程前沿(英文)》 2022年 第16卷 第3期 doi: 10.1007/s11783-021-1466-7

摘要:

• The α-diversities of resistome were lower in manure and compost than in soils.

关键词: Antibiotic resistance genes     Resistome     Bacterial taxonomy     Transmission chain    

Planet position errors in planetary transmission: Effect on load sharing and transmission error

Miguel IGLESIAS, Alfonso FERNáNDEZ, Ana DE-JUAN, Ramón SANCIBRIáN, Pablo GARCíA

《机械工程前沿(英文)》 2013年 第8卷 第1期   页码 80-87 doi: 10.1007/s11465-013-0362-7

摘要:

In this paper an advanced model of spur gear transmissions developed by the authors is used to study the influence of carrier planet pin hole position errors on the behaviour of the transmission. The model, initially conceived for external gear modeling, has been extended with internal meshing features, and thus increasing its capabilities to include planetary transmission modeling. The new features are presented, along with the summary of the model general approach. The parameters and characteristics of the planetary transmission used in the paper are introduced. The influence of carrier planet pin hole position errors on the planet load sharing is studied, and several static cases are given as examples in order to show the ability of the model. Tangential and radial planet pin hole position errors are considered independently, and the effect of the load level is also taken into account. It is also given attention to the effect on the transmission error of the transmission. Two different configurations for the planetary transmission are used, attending to the fixed or floating condition of the sun, and the differences in terms of load sharing ratio are shown.

关键词: gear     planetary     epicyclic     transmission     load sharing     transmission error    

Eliminating mother-to-child transmission of HBV: progress and challenges in China

Wenzhan Jing, Jue Liu, Min Liu

《医学前沿(英文)》 2020年 第14卷 第1期   页码 21-29 doi: 10.1007/s11684-020-0744-2

摘要: China has the world’s largest burden of hepatitis B virus (HBV) infection, but the country has made considerable progress in preventing its mother-to-child transmission (MTCT) in the past three decades. This feat is made possible due to the high coverage of birth-dose hepatitis B vaccine (HepB,>95%), hepatitis B surface antigen (HBsAg) screening for pregnant women (>99%), and hepatitis B immunoglobulin plus HepB for newborns whose mothers are HBsAg positive (>99%). Studies on the optimal antiviral treatment regimen for pregnant women with high HBV-DNA load have also been conducted. However, China still faces challenges in eliminating MTCT of HBV. The overall HBsAg prevalence among pregnant women is considered an intermediate endemic. The prevalence of HBsAg among pregnant women from remote, rural, or ethnic minority areas is higher than that of the national level because of limited health resources and public health education for HBV. The coverage for maternal and child healthcare and immunization services should be improved, especially in western regions. Integration of current services to prevent MTCT of HBV with other relevant health services can increase the acceptability, efficiency, and coverage of these services, particularly in remote areas and ethnic minority areas. By doing so, progress toward key milestones and targets to eliminate hepatitis B as the main public health threat by 2030 can be achieved.

关键词: hepatitis B virus     mother-to-child transmission     progress     challenge    

An approach for evaluating the impact of an intermittent renewable energy source on transmission expansion

Rongrit CHATTHAWORN,Surachai CHAITUSANEY

《信息与电子工程前沿(英文)》 2015年 第16卷 第10期   页码 871-882 doi: 10.1631/FITEE.1500049

摘要: We propose a new robust optimization approach to evaluate the impact of an intermittent renewable energy source on transmission expansion planning (TEP). The objective function of TEP is composed of the investment cost of the transmission line and the operating cost of conventional generators. A method to select suitable scenarios representing the intermittent renewable energy generation and loads is proposed to obtain robust expansion planning for all possible scenarios. A meta-heuristic algorithm called adaptive tabu search (ATS) is employed in the proposed TEP. ATS iterates between the main problem, which minimizes the investment and operating costs, and the subproblem, which minimizes the cost of power generation from conventional generators and curtailments of renewable energy generation and loads. The subproblem is solved by nonlinear programming (NLP) based on an interior point method. Moreover, the impact of an intermittent renewable energy source on TEP was evaluated by comparing expansion planning with and without consideration of a renewable energy source. The IEEE Reliability Test System 79 (RTS 79) was used for testing the proposed method and evaluating the impact of an intermittent renewable energy source on TEP. The results show that the proposed robust optimization approach provides a more robust solution than other methods and that the impact of an intermittent renewable energy source on TEP should be considered.

关键词: Adaptive tabu search     Renewable energy generation     Robust optimization     Transmission expansion planning    

标题 作者 时间 类型 操作

Design Method and Numerical Control Machining Principle for an Arbitrary n-polygon Noncircular Section

WU Yi-jie, LENG Hong-bin

期刊论文

Evaluation of 1,4-naphthoquinone derivatives as antibacterial agents: activity and mechanistic studies

期刊论文

Mechanistic insights into the selective photocatalytic degradation of dyes over TiO/ZSM-11

期刊论文

Recent advances in cycloaddition of CO with epoxides: halogen-free catalysis and mechanistic insights

期刊论文

Improved film evaporator for mechanistic understanding of microwave-induced separation process

Xin Gao, Dandan Shu, Xingang Li, Hong Li

期刊论文

doping boosted low-temperature NH-SCR activity of FeTiO catalyst: A microstructure analysis and reaction mechanistic

期刊论文

EDTA-intercalated layered double hydroxide for enhanced recovery of Cr(VI) and Congo red: Adsorptive and mechanistic

Jing Li, Haiqin Yu, Xue Zhang, Rixin Zhu, Liangguo Yan

期刊论文

Choosing configurations of transmission line tower grounding by back flashover probability value

Dmitry KUKLIN

期刊论文

Performance and mechanistic study on electrocoagulation process for municipal wastewater treatment based

Zhenlian Qi, Shijie You, Ranbin Liu, C. Joon Chuah

期刊论文

Cadmium removal mechanistic comparison of three Fe-based nanomaterials: Water-chemistry and roles of

期刊论文

Recent transmission of Mycobacterium tuberculosis in China: the implication of molecular epidemiology

null

期刊论文

Antibiotic resistome mostly relates to bacterial taxonomy along a suburban transmission chain

期刊论文

Planet position errors in planetary transmission: Effect on load sharing and transmission error

Miguel IGLESIAS, Alfonso FERNáNDEZ, Ana DE-JUAN, Ramón SANCIBRIáN, Pablo GARCíA

期刊论文

Eliminating mother-to-child transmission of HBV: progress and challenges in China

Wenzhan Jing, Jue Liu, Min Liu

期刊论文

An approach for evaluating the impact of an intermittent renewable energy source on transmission expansion

Rongrit CHATTHAWORN,Surachai CHAITUSANEY

期刊论文