资源类型

期刊论文 594

年份

2023 38

2022 43

2021 36

2020 39

2019 28

2018 39

2017 31

2016 27

2015 27

2014 29

2013 27

2012 30

2011 28

2010 40

2009 26

2008 23

2007 18

2006 7

2005 8

2004 12

展开 ︾

关键词

普光气田 7

评价指标 6

指标体系 4

评价 4

可持续发展 3

COVID-19 2

中国近海 2

制造强国 2

勘探开发 2

工程 2

效果评估 2

数值模拟 2

模糊综合评判 2

煤层气 2

现场监测 2

目标识别 2

绿色建筑 2

评价体系 2

评估 2

展开 ︾

检索范围：

排序： 展示方式：

ROUTE DEVELOPMENT, ANTIVIRAL STUDIES, FIELD EVALUATION AND TOXICITY OF AN ANTIVIRAL PLANT PROTECTANT

《农业科学与工程前沿（英文）》 2022年 第9卷 第1期 doi: 10.15302/J-FASE- 2021390

摘要：

It has previously been shown that tryptophan, the biosynthesis precursor of Peganum harmala alkaloids, and its derivatives have anti-TMV activity both in vitro and in vivo. Further exploration of this led to the identification of NK0238 as a highly effective agent for the prevention and control of diseases caused by plant viruses, but the existing routes are unsuitable for its large-scale synthesis. This study optimized a route for two-step synthesis of this virucide candidate via reaction of l-tryptophan with triphosgene to produce l-tryptophan-N-carboxylic anhydride, which then reacts with n-octylamine to give NK0238 at up to 94% yield and nearly 97% HPLC purity. In addition, the route was used for the preparation of NK0238 on a>40 g scale permitting further assessment of its antivirus activity in the greenhouse and field experiments, and toxicity tests. NK0238 exhibited useful antiviral activities against a variety of viruses both in greenhouse and field experiments. The toxicity tests showed that NK0238 was not acutely toxic to birds, fish, honey bees and silkworms. The optimized route provides a solid foundation for its large-scale synthesis and subsequent efficacy and toxicity studies, its excellent activity and safety make NK0238 a promising drug candidate for further development.

 

关键词： antiviral plant protectant / antiviral in the greenhouse / field evaluation / l-trp-NCA / synthesis optimization / toxicity tests    

HTML PDF 收藏

ROUTE DEVELOPMENT, ANTIVIRAL STUDIES, FIELD EVALUATION AND TOXICITY OF AN ANTIVIRAL PLANT PROTECTANT

Wentao XU, Hao TIAN, Hongjian SONG, Yuxiu LIU, Yongqiang LI, Qingmin WANG

《农业科学与工程前沿（英文）》   页码 110-119 doi: 10.15302/J-FASE-2021390

摘要： It has previously been shown that tryptophan, the biosynthesis precursor of alkaloids, and its derivatives have anti-TMV activity both and . Further exploration of this led to the identification of NK0238 as a highly effective agent for the prevention and control of diseases caused by plant viruses, but the existing routes are unsuitable for its large-scale synthesis. This study optimized a route for two-step synthesis of this virucide candidate via reaction of L-tryptophan with triphosgene to produce L-tryptophan- -carboxylic anhydride, which then reacts with -octylamine to give NK0238 at up to 94% yield and nearly 97% HPLC purity. In addition, the route was used for the preparation of NK0238 on a > 40 g scale permitting further assessment of its antivirus activity in the greenhouse and field experiments, and toxicity tests. NK0238 exhibited useful antiviral activities against a variety of viruses both in greenhouse and field experiments. The toxicity tests showed that NK0238 was not acutely toxic to birds, fish, honey bees and silkworms. The optimized route provides a solid foundation for its large-scale synthesis and subsequent efficacy and toxicity studies, its excellent activity and safety make NK0238 a promising drug candidate for further development.

关键词： antiviral plant protectant     antiviral in the greenhouse     field evaluation     L-trp-NCA     synthesis optimization     toxicity tests    

HTML PDF 收藏

Laboratory and field evaluation of asphalt pavement surface friction resistance

Zhong WU, Chris ABADIE

《结构与土木工程前沿（英文）》 2018年 第12卷 第3期   页码 372-381 doi: 10.1007/s11709-017-0463-1

摘要：

Pavement surface friction is a significant factor for driving safety and plays a critical role in reducing wet-pavement crashes. However, the current asphalt mixture design procedure does not directly consider friction as a requirement. The objective of this study was to develop a surface friction prediction model that can be used during a wearing course mixture design. To achieve the objective, an experimental study was conducted on the frictional characteristics of typical wearing course mixtures in Louisiana. Twelve wearing course mixtures including dense-graded and open-graded mixes with different combinations of aggregate sources were evaluated in laboratory using an accelerated polishing and testing procedure considering both micro- and macro texture properties. In addition, the surface frictional properties of asphalt mixtures were measured on twenty-two selected asphalt pavement sections using different in situ devices including Dynamic Friction Tester (DFT), Circular Texture Meter (CTM), and Lock-Wheel Skid Trailer (LWST). The results have led to develop a procedure for predicting pavement end-of-life skid resistance based on the aggregate blend polish stone value, gradation parameters, and traffic, which is suited in checking whether the selected aggregates in a wearing course mix design would meet field friction requirements under a certain design traffic polishing.

关键词： friction skid resistance     polishing     PSV     LWST     micro-texture     macro-texture    

HTML PDF 收藏

Full-scale site evaluation of ventilation expressway embankments underlain by warm permafrost along the

《结构与土木工程前沿（英文）》   页码 1047-1059 doi: 10.1007/s11709-023-0034-6

摘要： Ventilation embankments, including those with forced ventilation, natural ventilation, and combination of these, were adopted for the construction of the Gonghe−Yushu Expressway in warm permafrost areas. To evaluate the actual thermal performance of ventilation embankment in the Qinghai−Tibet Plateau, four types of ventilation embankments were selected as objects, and their long-term thermal characteristics were analyzed based on monitoring data. It was found that: 1) under the strong scale effect of a wide embankment, the crushed-rock embankment (CRE) was warming up and the permafrost table was declining year by year. Meanwhile, the combined ventilated slab and CRE and ventilated ducts embankment can effectively decrease the ground temperature and raise permafrost table in the year with a colder winter; 2) transverse temperature difference caused by the shady–sunny slope effect existed in all the four embankments. However, it was weakened by the combined ventilated slab and CRE and the ventilated ducts embankment due to their stronger cooling effect; and 3) the pre-existing embankment had a remarkable thermal disturbance to the adjacent newly-built embankment, so a reasonable embankment spacing should be considered in practical engineering. These findings would provide a reference for construction of expressway embankments in permafrost regions.

关键词： warm permafrost     expressway     ventilation embankments     temperature field    

HTML PDF 收藏

Novel soil quality indicators for the evaluation of agricultural management practices: a biological perspective

Giulia BONGIORNO

《农业科学与工程前沿（英文）》 2020年 第7卷 第3期   页码 257-274 doi: 10.15302/J-FASE-2020323

摘要：

Developments in soil biology and in methods to characterize soil organic carbon can potentially deliver novel soil quality indicators that can help identify management practices able to sustain soil productivity and environmental resilience. This work aimed at synthesizing results regarding the suitability of a range of soil biological and biochemical properties as novel soil quality indicators for agricultural management. The soil properties, selected through a published literature review, comprised different labile organic carbon fractions [hydrophilic dissolved organic carbon, dissolved organic carbon, permanganate oxidizable carbon (POXC), hot water extractable carbon and particulate organic matter carbon], soil disease suppressiveness measured using a - bioassay, nematode communities characterized by amplicon sequencing and qPCR, and microbial community level physiological profiling measured with MicroResp . Prior studies tested the sensitivity of each of the novel indicators to tillage and organic matter addition in ten European long-term field experiments (LTEs) and assessed their relationships with pre-existing soil quality indicators of soil functioning. Here, the results of these previous studies are brought together and interpreted relative to each other and to the broader body of literature on soil quality assessment. Reduced tillage increased carbon availability, disease suppressiveness, nematode richness and diversity, the stability and maturity of the food web, and microbial activity and functional diversity. Organic matter addition played a weaker role in enhancing soil quality, possibly due to the range of composition of the organic matter inputs used in the LTEs. POXC was the indicator that discriminated best between soil management practices, followed by nematode indices based on functional characteristics. Structural equation modeling shows that POXC has a central role in nutrient retention/supply, carbon sequestration, biodiversity conservation, erosion control and disease regulation/suppression. The novel indicators proposed here have great potential to improve existing soil quality assessment schemes. Their feasibility of application is discussed and needs for future research are outlined.

关键词： labile carbon     long-term field experiments     organic matter addition     soil biological indicators     tillage    

HTML PDF 收藏

Recent progress in electric-field assisted combustion: a brief review

《能源前沿（英文）》 2022年 第16卷 第6期   页码 883-899 doi: 10.1007/s11708-021-0770-z

摘要： The control of combustion is a hot and classical topic. Among the combustion technologies, electric-field assisted combustion is an advanced techno-logy that enjoys major advantages such as fast response and low power consumption compared with thermal power. However, its fundamental principle and impacts on the flames are complicated due to the coupling between physics, chemistry, and electromagnetics. In the last two decades, tremendous efforts have been made to understand electric-field assisted combustion. New observations have been reported based on different combustion systems and improved diagnostics. The main impacts, including flame stabilization, emission reduction, and flame propagation, have been revealed by both simulative and experimental studies. These findings significantly facilitate the application of electric-field assisted combustion. This brief review is intended to provide a comprehensive overview of the recent progress of this combustion technology and further point out research opportunities worth investigation.

关键词： electric field     combustion     flame stabilization     emission reduction     flame propagation    

HTML PDF 收藏

A MATLAB code for the material-field series-expansion topology optimization method

《机械工程前沿（英文）》 2021年 第16卷 第3期   页码 607-622 doi: 10.1007/s11465-021-0637-3

摘要： This paper presents a MATLAB implementation of the material-field series-expansion (MFSE) topo-logy optimization method. The MFSE method uses a bounded material field with specified spatial correlation to represent the structural topology. With the series-expansion method for bounded fields, this material field is described with the characteristic base functions and the corresponding coefficients. Compared with the conventional density-based method, the MFSE method decouples the topological description and the finite element discretization, and greatly reduces the number of design variables after dimensionality reduction. Other features of this method include inherent control on structural topological complexity, crisp structural boundary description, mesh independence, and being free from the checkerboard pattern. With the focus on the implementation of the MFSE method, the present MATLAB code uses the maximum stiffness optimization problems solved with a gradient-based optimizer as examples. The MATLAB code consists of three parts, namely, the main program and two subroutines (one for aggregating the optimization constraints and the other about the method of moving asymptotes optimizer). The implementation of the code and its extensions to topology optimization problems with multiple load cases and passive elements are discussed in detail. The code is intended for researchers who are interested in this method and want to get started with it quickly. It can also be used as a basis for handling complex engineering optimization problems by combining the MFSE topology optimization method with non-gradient optimization algorithms without sensitivity information because only a few design variables are required to describe relatively complex structural topology and smooth structural boundaries using the MFSE method.

关键词： MATLAB implementation     topology optimization     material-field series-expansion method     bounded material field     dimensionality reduction    

HTML PDF 收藏

Field test on temperature field and thermal stress for prestressed concrete box-girder bridge

Baoguo CHEN, Rui DING, Junjie ZHENG, Shibiao ZHANG

《结构与土木工程前沿（英文）》 2009年 第3卷 第2期   页码 158-164 doi: 10.1007/s11709-009-0002-9

摘要： A field test was conducted to investigate the distribution of temperature field and the variation of thermal stress for a prestressed concrete (PC) box-girder bridge. The change of hydration heat temperature consists of four periods: temperature rising period, constant temperature period, rapid temperature fall period and slow temperature fall period. The peak value of hydration heat temperature increases with the increasing casting temperature of concrete; the relation between them is approximately linear. According to field tests, the thermal stress incurred by hydration heat may induce temperature cracks on the PC box-girder. Furthermore, the nonlinear distribution of temperature gradient and the fluctuation of thermal stress induced by exposure to sunlight were also obtained based on continuous in-situ monitoring. Such results show that the prevailing Chinese Code (2004) is insufficient since it does not take into account the temperature gradient of the bottom slab. Finally, some preventive measures against temperature cracks were proposed based on related studies. The conclusions can provide valuable reference for the design and construction of PC box-girder bridges.

关键词： box-girder bridge     field test     hydration heat     temperature field     temperature gradient     thermal stress    

HTML PDF 收藏

Energy field-assisted high-speed dry milling green machining technology for difficult-to-machine metal

《机械工程前沿（英文）》 2023年 第18卷 第2期 doi: 10.1007/s11465-022-0744-9

摘要： Energy field-assisted machining technology has the potential to overcome the limitations of machining difficult-to-machine metal materials, such as poor machinability, low cutting efficiency, and high energy consumption. High-speed dry milling has emerged as a typical green processing technology due to its high processing efficiency and avoidance of cutting fluids. However, the lack of necessary cooling and lubrication in high-speed dry milling makes it difficult to meet the continuous milling requirements for difficult-to-machine metal materials. The introduction of advanced energy-field-assisted green processing technology can improve the machinability of such metallic materials and achieve efficient precision manufacturing, making it a focus of academic and industrial research. In this review, the characteristics and limitations of high-speed dry milling of difficult-to-machine metal materials, including titanium alloys, nickel-based alloys, and high-strength steel, are systematically explored. The laser energy field, ultrasonic energy field, and cryogenic minimum quantity lubrication energy fields are introduced. By analyzing the effects of changing the energy field and cutting parameters on tool wear, chip morphology, cutting force, temperature, and surface quality of the workpiece during milling, the superiority of energy-field-assisted milling of difficult-to-machine metal materials is demonstrated. Finally, the shortcomings and technical challenges of energy-field-assisted milling are summarized in detail, providing feasible ideas for realizing multi-energy field collaborative green machining of difficult-to-machine metal materials in the future.

关键词： difficult-to-machine metal material     green machining     high-speed dry milling     laser energy field-assisted milling     ultrasonic energy field-assisted milling     cryogenic minimum quantity lubrication energy field-assisted milling    

HTML PDF 收藏

Temperature field simulation of laser homogenizing equipment

Juanjuan WANG, Yunshan WANG, Fudong ZHU

《机械工程前沿（英文）》 2009年 第4卷 第1期   页码 49-52 doi: 10.1007/s11465-009-0005-1

摘要： The laser homogenizing equipment was devised using the ring scanning principle. Its working principle is explained. A laser scanning ring facula is obtained when the laser beam goes through the equipment’s optical system rotating with high-frequency. The scanning ring facula’s mathematic model is established based on the temperature field’s superposing principle. The ring facula’s light intensity distribution and temperature distribution characteristics are achieved by simulating its temperature field. By studying the effect of parameters on the temperature field, the best parameter can be found. Results show that favorable temperature distribution characteristics can be attained by choosing appropriate parameters, and even the thermal effect can be realized by utilizing the circumference power compensating for the heat exchange lost in the horizontal direction. The uniform hardness layer and better process quality can be attained using the ring facula optimized for metal laser heat treatment.

关键词： laser homogenizing technology     laser scanning ring facula     temperature field    

HTML PDF 收藏

Sulige Gas Field super project

Wenrui HU, Jingwei BAO, Pengcheng JI

《工程管理前沿（英文）》 2017年 第4卷 第3期   页码 379-384 doi: 10.15302/J-FEM-2017107

HTML PDF 收藏

A FEniCS implementation of the phase field method for quasi-static brittle fracture

HIRSHIKESH, Sundararajan NATARAJAN, Ratna Kumar ANNABATTULA

《结构与土木工程前沿（英文）》 2019年 第13卷 第2期   页码 380-396 doi: 10.1007/s11709-018-0471-9

摘要： In the recent years, the phase field method for simulating fracture problems has received considerable attention. This is due to the salient features of the method: 1) it can be incorporated into any conventional finite element software; 2) has a scalar damage variable is used to represent the discontinuous surface implicitly and 3) the crack initiation and subsequent propagation and branching are treated with less complexity. Within this framework, the linear momentum equations are coupled with the diffusion type equation, which describes the evolution of the damage variable. The coupled nonlinear system of partial differential equations are solved in a ‘staggered’ approach. The present work discusses the implementation of the phase field method for brittle fracture within the open-source finite element software, FEniCS. The FEniCS provides a framework for the automated solutions of the partial differential equations. The details of the implementation which forms the core of the analysis are presented. The implementation is validated by solving a few benchmark problems and comparing the results with the open literature.

关键词： phase field method     FEniCS     brittle fracture     crack propagation     variational theory of fracture    

HTML PDF 收藏

罗布泊核试验区自然环境变化的地球卫星观测分析

胡东生,张华京,庞西磊,徐冰,于学峰,田新红,安芷生,张国伟

《中国工程科学》 2008年 第10卷 第9期   页码 31-38

摘要：

运用地球卫星观测手段及遥感信息提取技术及区域调查研究成果，首次对中国罗布泊核试验区进行全面分析及初步综合评价，揭示了鲜为人知的核爆炸效应及地质环境响应事件，对人类极端作用与重大工程环境及胁迫影响过程有了清晰实际的第一性材料，通过宏观清理和典型筛选对试验区自然环境要素变化进行逐项材料挖掘及客观评价，为国家安全利用核能与综合评估核环境及机动发展核战略提供科学基础数据。

关键词： 地球卫星观测     核试验区     核爆炸效应及地质环境响应过程     自然环境综合评价     中国罗布泊    

HTML PDF 收藏

Centrifuge model test and field measurement analysis for foundation pit with confined water

Chunlin DING , Xiaohong MENG ,

《结构与土木工程前沿（英文）》 2009年 第3卷 第3期   页码 299-304 doi: 10.1007/s11709-009-0035-0

摘要： The similarity law of centrifuge test was developed for the seepage field and stress field of a foundation pit with confined water by analyzing control equations, and a similarity index and a similarity coefficient of centrifuge test were obtained. Based on the deep foundation pit of the Huangxing Road Station of the Shanghai metro line M8, the deformation stability of the pit was tested. Finally, a comparative study was conducted on the test results of the pit deformation and the field measurement results. Comparison results show that the pit deformation regularity of the test is basically identical with that of the field measurement, and the difference in pit deformation between the test and the field measurement is within 50%. The centrifuge model test can effectively simulate the displacement response of the ground and retaining structure during dewatering and excavation for the pit with confined water, which provides a reliable basis for the design and construction of the pit with confined water.

关键词： foundation pit with confined water     centrifuge model test     seepage-stress coupling field     similarity relation     field measurement     deformation    

HTML PDF 收藏

Study on the measurement of temperature field using laser holographic interferometry

Jinrong ZHU, Suyi HUANG, Wei LV, Huaichun ZHOU

《能源前沿（英文）》 2011年 第5卷 第1期   页码 120-124 doi: 10.1007/s11708-010-0107-9

摘要： The temperature field of an axisymmetric ethylene diffusion flame is measured using laser holographic interferometry. Temperature field inversion is completed with the aid of components distribution divided from numerical simulation of combustion and air components assumption. Error analysis of key steps is conducted using the theoretical formula of interference temperature measurement and characteristic structure of fringes obtained from optical simulation. Based on the calculation and analysis, air components assumption will not cause significant error in the low temperature region but will result in high error in the high temperature region. Moreover, the small error in environmental temperature measurement transfer to a high temperature range will expand more than tenfold. Results of temperature measurement using air components assumption relative to combustion simulation require the greatest amendment amounting to seven percent.

关键词： temperature field     flame     error analysis     holographic interferometry    

HTML PDF 收藏

标题 作者 时间 类型 操作

ROUTE DEVELOPMENT, ANTIVIRAL STUDIES, FIELD EVALUATION AND TOXICITY OF AN ANTIVIRAL PLANT PROTECTANT

期刊论文

ROUTE DEVELOPMENT, ANTIVIRAL STUDIES, FIELD EVALUATION AND TOXICITY OF AN ANTIVIRAL PLANT PROTECTANT

Wentao XU, Hao TIAN, Hongjian SONG, Yuxiu LIU, Yongqiang LI, Qingmin WANG

期刊论文

Laboratory and field evaluation of asphalt pavement surface friction resistance

Zhong WU, Chris ABADIE

期刊论文

Full-scale site evaluation of ventilation expressway embankments underlain by warm permafrost along the

期刊论文

Novel soil quality indicators for the evaluation of agricultural management practices: a biological perspective

Giulia BONGIORNO

期刊论文

Recent progress in electric-field assisted combustion: a brief review

期刊论文

A MATLAB code for the material-field series-expansion topology optimization method

期刊论文

Field test on temperature field and thermal stress for prestressed concrete box-girder bridge

Baoguo CHEN, Rui DING, Junjie ZHENG, Shibiao ZHANG

期刊论文

Energy field-assisted high-speed dry milling green machining technology for difficult-to-machine metal

期刊论文

Temperature field simulation of laser homogenizing equipment

Juanjuan WANG, Yunshan WANG, Fudong ZHU

期刊论文

Sulige Gas Field super project

Wenrui HU, Jingwei BAO, Pengcheng JI

期刊论文

A FEniCS implementation of the phase field method for quasi-static brittle fracture

HIRSHIKESH, Sundararajan NATARAJAN, Ratna Kumar ANNABATTULA

期刊论文

罗布泊核试验区自然环境变化的地球卫星观测分析

胡东生,张华京,庞西磊,徐冰,于学峰,田新红,安芷生,张国伟

期刊论文

Centrifuge model test and field measurement analysis for foundation pit with confined water

Chunlin DING , Xiaohong MENG ,

期刊论文

Study on the measurement of temperature field using laser holographic interferometry

Jinrong ZHU, Suyi HUANG, Wei LV, Huaichun ZHOU

期刊论文