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Experimental study of pollution effect on the behavior of high voltage insulators under alternative current

Hani BENGUESMIA, Nassima M’ZIOU, Ahmed BOUBAKEUR

《能源前沿（英文）》 2021年第15卷第1期页码 213-221 doi: 10.1007/s11708-017-0479-1

摘要： In this paper, the impact of the conductivity and the distribution of pollution on the behavior of the high voltage insulator cap and pin 1512L, artificially polluted is described. An experimental model in form of a disc is proposed. This experimental model reproduces the real model which is the 1512L insulator. Besides, a comparative study is presented. For this comparative study, different solutions are adopted to s`imulate the pollution (containing NaCl+ distilled water) that has different conductivities for a discontinuous distribution of the pollution on the insulator under an AC voltage. Furthermore, the influence of the pollution on the flashover voltage and the leakage current is studied. Finally, the behavior of real and experimental model of the insulator is investigated.

关键词： 1512L insulator circular model artificial pollution flashover leakage current discontinuous pollution high voltage

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Comments on the special issue on forestry of

John L. INNES

《农业科学与工程前沿（英文）》 2017年第4卷第4期页码 502-503 doi: 10.15302/J-FASE-2017189

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PD-1/PD-L1 blockade in cervical cancer: current studies and perspectives

Yumeng Wang, Guiling Li

《医学前沿（英文）》 2019年第13卷第4期页码 438-450 doi: 10.1007/s11684-018-0674-4

摘要： Cervical cancer (CC) is the fourth most commonly diagnosed female malignancy and a leading cause of cancer-related mortality worldwide, especially in developing countries. Despite the use of advanced screening and preventive vaccines, more than half of all CC cases are diagnosed at advanced stages, when therapeutic options are extremely limited and side effects are severe. Given these circumstances, new and effective treatments are needed. In recent years, exciting progress has been made in immunotherapies, including the rapid development of immune checkpoint inhibitors. Checkpoint blockades targeting the PD-1/PD-L1 axis have achieved effective clinical responses with acceptable toxicity by suppressing tumor progression and improving survival in several tumor types. In this review, we summarize recent advances in our understanding of the PD-1/PD-L1 signaling pathway, including the expression patterns of PD-1/PD-L1 and potential PD-1/PD-L1-related therapeutic strategies for CC.

关键词： PD-1 PD-L1 immune checkpoint blockade antibody immunotherapy cervical cancer

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Shear design of high strength concrete prestressed girders

Emad L. LABIB,Hemant B. DHONDE,Thomas T. C. HSU,Y. L. MO

《结构与土木工程前沿（英文）》 2014年第8卷第4期页码 373-387 doi: 10.1007/s11709-014-0087-7

摘要： Normal strength prestressed concrete I-girders are commonly used as the primary superstructure components in highway bridges. However, shear design guidelines for high strength PC girders are not available in the current structural codes. Recently, ten 7.62 m (25 feet) long girders made with high strength concrete were designed, cast, and tested at the University of Houston (UH) to study the ultimate shear strength and the shear concrete contribution ( ) as a function of concrete strength ( ). A simple semi-empirical set of equations was developed based on the test results to predict the ultimate shear strength of prestressed concrete I-girders. The UH-developed set of equations is a function of concrete strength ( ), web area ( ), shear span to effective depth ratio ( / ), and percentage of transverse steel ( ). The proposed UH-Method was found to accurately predict the ultimate shear strength of PC girders with concrete strength up to 117 MPa (17000 psi) ensuring satisfactory ductility. The UH-Method was found to be not as overly conservative as the ACI-318 (2011) code provisions, and also not to overestimate the ultimate shear strength of high strength PC girders as the AASHTO LRFD (2010) code provisions. Moreover, the proposed UH-Method was found fairly accurate and not exceedingly conservative in predicting the concrete contribution to shear for concrete strength up to 117 MPa (17000 psi).

关键词： shear design high strength concrete prestressed girders full-scale tests

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Urban watershed management under rapid urbanization

Pengfei DU, Haifeng JIA, Shaw L. YU

《环境科学与工程前沿（英文）》 2012年第6卷第5期页码 595-595 doi: 10.1007/s11783-012-0452-5

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Recombinant aspartate aminotransferase-catalyzed synthesis of L-4-fluorophenylalanine

CHEN Meijuan, JIA Honghua, CHEN Yongsheng, JIANG Min, WEI Ping

《化学科学与工程前沿（英文）》 2008年第2卷第2期页码 220-223 doi: 10.1007/s11705-008-0041-0

摘要： L-4-Fluorophenylalanine (FPhe) was prepared from 4-fluorophenylpyruvate (FPPA) catalyzed by aspartate aminotransferase (Asp-AT) of the recombinant BL21-pET/aspC. After 12 h enzymatic reaction, the FPPA conversion was over 90% and the yield of FPhe could be above 85% under the following optimal conditions: 37°C, pH value range of 5.0–8.0, 5.5 mass ratio of cell to FPPA, 0.6% (w/v) of Tween 80, 7.08 g/L FPPA, and 1.6 of molar ratio of L-Asp to FPPA.

关键词： L-4-Fluorophenylalanine Asp-AT aspartate aminotransferase 4-fluorophenylpyruvate FPPA

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Effects of different doses of cadmium on secondary metabolites and gene expression in Artemisia annua L.

null

《医学前沿（英文）》 2017年第11卷第1期页码 137-146 doi: 10.1007/s11684-016-0486-3

摘要：

This study aims to elucidate the underlying molecular mechanisms of artemisinin accumulation induced by cadmium (Cd). The effects of different Cd concentrations (0, 20, 60, and 120 μmol/L) on the biosynthesis of Artemisia annua L. were examined. Intermediate and end products were quantified by HPLC-ESI-MS/MS analysis. The expression of key biosynthesis enzymes was also determined by qRT-PCR. The results showed that the application of treatment with 60 and 120 μmol/L Cd for 3 days significantly improved the biosynthesis of artemisinic acid, arteannuin B, and artemisinin. The concentrations of artemisinic acid, arteannuin B, and artemisinin in the 120 μmol/L Cd-treated group were 2.26, 102.08, and 33.63 times higher than those in the control group, respectively. The concentrations of arteannuin B and artemisinin in 60 μmol/L Cd-treated leaves were 61.10 and 26.40 times higher than those in the control group, respectively. The relative expression levels of HMGR, FPS, ADS, CYP71AV1, DBR2, ALDH1, and DXR were up-regulated in the 120 μmol/L Cd-treated group because of increased contents of artemisinic metabolites after 3 days of treatment. Hence, appropriate doses of Cd can increase the concentrations of artemisinic metabolites at a certain time point by up-regulating the relative expression levels of key enzyme genes involved in artemisinin biosynthesis.

关键词： Cd secondary metabolites gene expressions Artemisia annua L.

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Size-controlled green synthesis of silver nanoparticles assisted by L-cysteine

Wenchao Zhang,Lin Zhang,Yan Sun

《化学科学与工程前沿（英文）》 2015年第9卷第4期页码 494-500 doi: 10.1007/s11705-015-1527-1

摘要： A green and size-controlled synthesis of silver nanoparticles (Ag NPs) in aqueous solution with the assistance of L-cysteine is presented. The size of Ag NPs decreases with the increase of L-cysteine concentration, and thus can be controlled by adjusting L-cysteine concentration. TEM analysis shows that Ag NPs with an average size of 3 nm can be produced in the presence of 1.0 mmol/L L-cysteine, about one sixth of the size of Ag NPs obtained in the absence of L-cysteine (17 nm). The as-synthesized silver colloidal solution is stable and can be stored at room temperature for at least two months without any precipitation. This L-cysteine assisted method is simple, feasible and efficient, and would facilitate the production and application of Ag NPs.

关键词： nanoparticles silver L-cysteine size distribution synthesis

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Reactive extraction for preparation of hydrogen peroxide under pressure

CHENG Yongxi, LI Hongtao, WANG Li, LÜ Shuxiang

《化学科学与工程前沿（英文）》 2008年第2卷第3期页码 335-340 doi: 10.1007/s11705-008-0042-z

摘要： The preparation of hydrogen peroxide from anthrahydroquinone by reactive extraction was investigated. The integration process of oxidation of anthrahydroquinone by air and extraction of hydrogen peroxide from the organic phase with water was carried out in a sieve plate column under pressure. The conversion of anthrahydroquinone increased with increasing pressure resulting in an increase of hydrogen peroxide concentration in the aqueous phase. However, no change in extraction efficiency of hydrogen peroxide was observed. A mathematical model for gas-liquid-liquid reactive extraction was established. In the model, the effects of pressure and gas superficial velocity on reaction were considered. With increasing gas superficial velocity, the conversion of anthrahydroquinone increased, and the fraction of hydrogen peroxide extracted reached a plateau with a maximum of 72.94%. However, both the conversion of anthrahydroquinone and the fraction of hydrogen peroxide extracted decreased with increasing organic phase superficial velocity.

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Orientation effect of electropolishing characteristics of 316L stainless steel fabricated by laser powder

《机械工程前沿（英文）》 2021年第16卷第3期页码 580-592 doi: 10.1007/s11465-021-0633-7

摘要： 3D metal printing process has attracted increasing attention in recent years due to advantages, such as flexibility and rapid prototyping. This study aims to investigate the orientation effect of electropolishing characteristics on different surfaces of 316L stainless steel fabricated by laser powder bed fusion (L-PBF), considering that the rough surface of 3D printed parts is a key factor limiting its applications in the industry. The electropolishing characteristics on the different surfaces corresponding to the building orientation in selective laser melting are studied. Experimental results show that electrolyte temperature has critical importance on the electropolishing, especially for the vertical direction to the layering plane. The finish of electropolished surfaces is affected by the defects generated during L-PBF process. Thus, the electropolished vertical surface has higher surface roughness Sa than the horizontal surface. The X-ray photoelectron spectroscopy spectra show that the electropolished horizontal surface has higher Cr/Fe element ratio than the vertical surface. The electropolished horizontal surface presents higher corrosion resistance than the vertical surface by measuring the anodic polarization curves and fitting the equivalent circuit of experimental electrochemical impedance spectroscopy.

关键词： electropolishing laser powder bed fusion 316L stainless steel corrosion resistance microstructure

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Quality Function Deployment Implementation in Construction: A Systematic Literature Review

Cudney,William L. Gillis

《工程管理前沿（英文）》 2016年第3卷第3期页码 224-230 doi: 10.15302/J-FEM-2016036

摘要： The construction of new buildings represents a significant investment. The goal of new building construction is to maximize value and minimize cost while staying on time and within budget. Translating customer requirements into engineering terms for new construction design is vital for a construction project to be successful. Quality function deployment has been successfully used in product development to capture the voice of the customer and translate it into engineering characteristics. Quality function deployment then carries these parameters into production and service to ensure the voice of the customer is being met with the final product. The house of quality, a tool within quality function deployment, can provide a means for comparison of owner’s project requirements and the proposed design, along with identifying how the design decisions impact meeting customer requirements and green building requirements. Quality function deployment can effectively link the project phases through design and construction and into operations and maintenance to ensure the owner’s project requirements are met with the final building. This research identifies and categorizes studies of quality function deployment applications in construction. The research method used is a systematic literature review from databases related to quality function deployment in the construction industry published in the periodicals through 2016. The principal findings of implementations, practices, and integrated approaches are then summarized. This article intends to propel further research of quality function deployment in the construction sector.

关键词： construction engineering management quality function deployment systematic review

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地下工程的发展提升现代生活质量

Raymond L. Sterling

《工程（英文）》 2017年第3卷第6期页码 780-781 doi: 10.1016/j.eng.2017.12.006

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Effects of iron oxide nanoparticles on phenotype and metabolite changes in hemp clones ( L.)

《环境科学与工程前沿（英文）》 2022年第16卷第10期 doi: 10.1007/s11783-022-1569-9

摘要：

● Fe₃O₄ NPs increased the biomass and chlorophyll content of hemp clones.

关键词： Fe₃O₄ nanoparticle Hemp Growth enhancement THC Metabolite

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A Standard for the Commissioning Process

William L. Gillis,Elizabeth A. Cudney

《工程管理前沿（英文）》 2015年第2卷第1期页码 39-51 doi: 10.15302/J-FEM-2015006

摘要： The demand for commissioning services for new-building construction projects is experiencing rapid growth. Commissioning (Cx) is touted as being a quality-focused process for ensuring the owner’s project requirements (OPR) are met by design, final construction, and the operations of a building. To an owner this is just what is needed to receive a perfect building at occupancy. However, as many owners have realized, the Cx process does not guarantee the completed building will be what was expected. It should be pointed out that this is typically not caused by the Cx process, but the Cx process should or could have identified, in the early phases of the project, many of the issues that made it through to the completed building. There are a number of reasons why the Cx services received may not be optimal. Often it is poor communication and the transfer of knowledge between project teams. Cx should and can facilitate both communication and the transfer of knowledge from phase to phase. An adaptation of the quality function deployment (QFD) four-phase model can accomplish this by filling the gaps among the major Cx activities and provide a standard approach to the process. The four-phase model effectively links each of the Cx activities to each other and back to the OPR, providing a method for improved communication and knowledge transfer. This paper investigates some potential reasons for inconsistent Cx services, presents an argument for the need of a Cx standard, and proposes a potential standard.

关键词： construction engineering management quality commissioning

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Synthesis and characterization of well-defined comb-like branched polymers

LI Aixiang, LU Zaijun, LÜ Zijian

《化学科学与工程前沿（英文）》 2008年第2卷第4期页码 407-411 doi: 10.1007/s11705-008-0064-6

摘要： Well-defined comb-like branched polymers having one branch in each repeating unit have been successfully synthesized by the coupling reaction of living polystyrene (PS) and polyisoprene (PI) anions with 1, 1-diphenylethenyl (DPE) groups along PS backbone prepared via atom transfer radical polymerization (ATRP) of 4-vinylbenzyloxy benzophenone (Sc) followed by Wittig reaction. The resulting comb-like branched polymers were characterized by IR, H-NMR, gel permeation chromatography (GPC) and static light scattering (SLS) in detail. The effect of living chains and DPE group molar ratio on grafting efficiency was discussed. The results show the coupling reaction of living chains and DPE groups was highly effective, and the coupling efficiency can be controlled via the feed molar ratios of living chains and DPE groups. Moreover, the effect of molecular weights of backbone (PSe) and PSLi or PILi on grafting efficiency was also discussed. The results show that when excess living polymers were used, the almost quantitative grafting efficiency could be achieved.

关键词： grafting efficiency polyisoprene quantitative grafting effective molecular