资源类型

期刊论文 40

年份

2023 2

2022 6

2021 2

2020 6

2019 2

2018 1

2017 4

2016 1

2015 1

2014 2

2013 2

2012 2

2010 4

2009 1

2008 1

2003 3

展开 ︾

关键词

稀土元素 2

Cu(In 1

Ga)Se2 1

PDT 1

中医 1

五行 1

光学元件；精密制造；超精密机床；超精密加工；光学加工 1

冲刷坑 1

协同机制 1

协同要素 1

参考线 1

双区模型 1

反Douglas算法 1

可拓评价 1

多波束测深数据 1

大科学工程；创新体系；创新要素；协同创新；创新成就 1

崩岸 1

形态要素 1

技术创新网络 1

展开 ︾

检索范围：

排序： 展示方式：

Repeats in the transcribed regions: comprehensive characterization and comparison of

Manosh Kumar BISWAS, Christoph MAYER, Xiuxin DENG

《农业科学与工程前沿（英文）》 2017年 第4卷 第4期   页码 421-432 doi: 10.15302/J-FASE-2017160

摘要： A large number of expressed sequences tags are available for spp., which provides an opportunity to understand genomic organization of the transcribed regions. Here, we report a detailed analysis of repetitive elements including tandem repeats (TRs) and transposable elements (TEs) in the transcribed region of the spp. On average, 22% of the expressed sequence tags (ESTs) contain TRs. The relative density of TR classes is highly taxon-specific. For instance, has a high relative density of mononucleotide repeats, whereas dinucleotide repeats are rare. The proportions of 2–6, 7–30 and 31–50 bp repeats were almost identical in all studied species except for and . We found that<1% of the citrus ESTs have a similarity with transposable elements. Transcriptional activity of transposable element families varied even within the same class of elements. A high proportion of transcriptional activity was observed for -like TEs compare to other TE classes. While TEs are relatively rare, TRs are abundant elements in ESTs of citrus. The high proportion of TRs that have a unit size longer than 6 bp raises the question about a possible functional or evolutionary role of these elements.

关键词： Citrus spp.     tandem repeats     transcribed region     transposable elements    

HTML PDF 收藏

Assessment of mobile and potential mobile trace elements extractability in calcareous soils using different

Mohsen Jalali, Ziba Hurseresht

《环境科学与工程前沿（英文）》 2020年 第14卷 第1期 doi: 10.1007/s11783-019-1186-4

摘要： DTPA and NH4OAc, HNO3 and EDTA, and MgCl2 and NH4NO3 had similar behavior. In NH4OAc, DTPA, and EDTA, the possibility of re-adsorption of trace elements is low. CaCl2 may be more suitable than other extracts in calcareous soils. Understanding trace elements mobility in soils, extracting agents, and their relationships with soil components, are essential for predicting their movement in soil profile and availability to plants. A laboratory study was conducted to evaluate extractability of cadmium (Cd), cobalt (Co), copper (Cu), nickel (Ni), and zinc (Zn) from calcareous soils utilizing various extracting agents to be specific CaCl2, DTPA, EDTA, HNO3, MgCl2, NaNO3, NH4NO3, and NH4OAc. Cluster analysis indicated that DTPA and NH4OAc, HNO3 and EDTA, and MgCl2 and NH4NO3 extracting agents yielded comparative values, whereas NaNO3 and CaCl2 have shown different behavior than other extracting agents for all studied trace elements. The speciation of extracted trace elements in solutions indicated that in the CaCl2, NaNO3, NH4NO3, and MgCl2 extracting agents most extracted Cd, Co, Ni, Zn, and part of Cu were as free ions and may be re-adsorbed on soils, leading to lower extractability, whereas, in the case of HNO3 extracting agent, the likelihood of re-adsorption of trace elements may be little. The results of speciation of trace elements using NH4OAc, DTPA, and EDTA extracting agents showed that Me-(Acetate)3–, Me-(Acetate)2(aq), Me(DTPA)3−, Me(EDTA)2−, and MeH(EDTA)– complexes dominated in solutions indicating that the extracted trace elements may not be re-adsorbed on soils, leading to higher extractability. The results of this study are useful for short and long-term evaluations of trace elements mobility and further environmental impacts.

关键词： Mobility     Calcareous soils     Extracting agents     Trace elements    

HTML PDF 收藏

Linking elements to outcomes of knowledge transfer in the project environment: Current review and future

《工程管理前沿（英文）》 2022年 第9卷 第2期   页码 221-238 doi: 10.1007/s42524-022-0195-3

摘要： A project is a specific effort to create a unique product, so it is a favorable place for knowledge creation and development. Knowledge can be transferred inside and outside projects and their parent project-based organizations, thus affecting project performance and organizational competitiveness. However, the current research on the elements and outcomes of knowledge transfer (KT) in the project environment lacks completeness and clarity, and that on the different levels of KT is fragmented. This study aims to conduct comprehensive research to determine and link the elements and outcomes of KT in the project environment. The authors systematically analyzed the relevant literature from 2000 to 2021, which showed an increasing publication trend. They divided KT in the project environment into three levels according to the transfer scenario: Intra-project, cross-project, and cross-organizational KT. Five-dimensional transfer elements and two-dimensional transfer outcomes were then identified and analyzed from previous literature. Lastly, the relationships between the transfer elements and outcomes were gathered to create a comprehensive model. Importantly, the knowledge gap in the current literature was highlighted, and future research directions were put forward. This study builds a theoretical framework linking transfer elements to outcomes that can serve as a basis for scholars and practitioners to develop effective strategies for KT in the project environment.

关键词： knowledge transfer     knowledge management     project management     project environment     literature review    

HTML PDF 收藏

A family of non-conforming crack front elements of quadrilateral and triangular types for 3D crack problems

Guizhong XIE, Fenglin ZHOU, Hao LI, Xiaoyu WEN, Fannian MENG

《机械工程前沿（英文）》 2019年 第14卷 第3期   页码 332-341 doi: 10.1007/s11465-019-0540-3

摘要： This study focuses on establishing non-conforming crack front elements of quadrilateral and triangular types for 3D crack problems when the dual boundary element method is applied. The asymptotic behavior of the physical variables in the area near the crack front is fully considered in the construction of the shape function. In the developed quadrilateral and triangular crack front elements, the asymptotic term, which captures the asymptotic behavior of the physical variable, is multiplied directly by the conventional Lagrange shape function to form a new crack front shape function. Several benchmark numerical examples that consider penny-shaped cracks and straight-edge crack problems are presented to illustrate the validity and efficiency of the developed crack front elements.

关键词： Taylor expansion     crack front elements     stress intensity factors     dual boundary element method    

HTML PDF 收藏

Assessment of leaching behavior and human bioaccessibility of rare earth elements in typical hospital

Chunfeng Wang, Guanfei Chen, Yanchen Zhu, Dan Yao, Wanfeng Wang, Lianjun Wang

《环境科学与工程前沿（英文）》 2017年 第11卷 第6期 doi: 10.1007/s11783-017-0946-2

摘要： Leaching behavior and gastrointestinal bioaccessibility of rare earth elements (REEs) from hospital waste incineration (HWI) fly and bottom ash samples collected from Beijing and Nanjing Cities were assessed. In the same ash sample, the leaching concentrations of individual REEs determined by the Toxicity Characteristic Leaching Procedure (TCLP) were higher than those detected by the European standard protocol (EN-type test), thereby suggesting that the low pH value of leaching solution was an important factor influencing the leachability of REE. The REE bioaccessibility results, which were evaluated using the physiologically based extraction test (PBET), indicated that REEs were highly absorbed during gastric phase by dissolution; and subsequently precipitated and/or re-adsorbed in small intestinal phase. The relative amounts of the total REEs extracted by the TCLP method, EN-type test and PBET test were compared. In addition to the pH value of extraction solutions, the chelating role of REEs with organic ligands used in the PBET method was also an important parameter affecting REE adsorption in human body. Additionally, this study showed that REEs were extracted by these methods as concomitants of heavy metals and anions (NO , F , SO , and Cl ) from HWI ash, which probably caused the remarkably complex toxicity on human body by the exposure pathway.

关键词： Assessment     Rare earth elements     Leaching behavior     Bioaccessibility     Hospital waste    

HTML PDF 收藏

Preconcentration of trace elements by adsorption onto a niobium wire for electrothermal atomization atomic

Satoshi KANECO, Hiroaki KITANAGA, Hideyuki KATSUMATA, Tohru SUZUKI

《化学科学与工程前沿（英文）》 2012年 第6卷 第4期   页码 432-435 doi: 10.1007/s11705-012-1219-z

摘要： In the present work, a new preconcentration method of trace elements by adsorption onto a niobium wire has been developed for electrothermal atomization atomic absorption spectrometry (ETAAS) with a tungsten tube atomizer. Detection limits (pg·mL ) by this method combined with ETAAS were 45 for bismuth, 7.0 for cadmium, 20 for copper, 1.3 for gold, 36 for lead, 65 for manganese, 9.5 for rhodium and 19 for silver.

关键词： preconcentration     adsorption onto niobium wire     electrothermal atomization atomic absorption spectrometry     tungsten tube atomizer     trace elements    

HTML PDF 收藏

Assessment of pollution of potentially harmful elements in soils surrounding a municipal solid waste

Ying Han, Huiting Xie, Wenbin Liu, Haifeng Li, Mengjing Wang, Xuebin Chen, Xiao Liao, Nan Yan

《环境科学与工程前沿（英文）》 2016年 第10卷 第6期 doi: 10.1007/s11783-016-0873-7

摘要： Potentially harmful elements in ambient soil of a MSWI were assessed. Spatial distribution of potential ecological risk index was investigated. Health risk assessment of potentially harmful elements in soil was evaluated. Hg in the soil posed health hazards to the local population. We assessed the contamination levels of Mn, Zn, Cr, Cu, Ni, Pb, As and Hg and the risks posed by these potentially harmful elements in top-soils around a municipal solid waste incinerator (MSWI). We collected 20 soil samples, with an average pH of 8.1, and another fly ash sample emitted from the MSWI to investigate the concentrations of these elements in soils. We determined the concentrations of these elements by inductively coupled plasma–optical emission spectrometer (ICP-OES), except for Hg, which we measured by AF-610B atomic fluorescence spectrometer ( ). We assessed the risks of these elements through the use of geoaccumulation index ( ), potential ecological risk index ( ), hazard quotient ( ) and cancer risk ( ). The results showed that concentrations of potentially harmful elements in soil were influenced by the wind direction, and the concentrations of most elements were higher in the area northwest of the MSWI, compared with the area southeast of the incinerator, with the exception of As; these results were in accordance with those results acquired from our contour maps. According to the values, some soil samples were clearly polluted by Hg emissions. However, the health risk assessment indicated that the concentrations of Hg and other elements in soil did not pose non-carcinogenic risks to the local populations. This was also the case for the carcinogenic risks posed by As, Cr, and Ni. The carcinogenic risk posed by As was higher, in the range 6.49 × 10 –9.58 × 10 , but this was still considered to be an acceptable level of risk.

关键词： Soil     Potentially harmful elements     Contamination     Kriging interpolation     Risk assessment     Wind direction    

HTML PDF 收藏

Computational modeling of fracture in capsule-based self-healing concrete: A 3D study

《结构与土木工程前沿（英文）》 2021年 第15卷 第6期   页码 1337-1346 doi: 10.1007/s11709-021-0781-1

摘要： We present a three-dimensional (3D) numerical model to investigate complex fracture behavior using cohesive elements. An efficient packing algorithm is employed to create the mesoscale model of heterogeneous capsule-based self-healing concrete. Spherical aggregates are used and directly generated from specified size distributions with different volume fractions. Spherical capsules are also used and created based on a particular diameter, and wall thickness. Bilinear traction-separation laws of cohesive elements along the boundaries of the mortar matrix, aggregates, capsules, and their interfaces are pre-inserted to simulate crack initiation and propagation. These pre-inserted cohesive elements are also applied into the initial meshes of solid elements to account for fracture in the mortar matrix. Different realizations are carried out and statistically analyzed. The proposed model provides an effective tool for predicting the complex fracture response of capsule-based self-healing concrete at the meso-scale.

关键词： 3D fracture     self-healing concrete     spherical     cohesive elements     heterogeneous    

HTML PDF 收藏

A 14-year measurement of toxic elements in atmospheric particulates in Hong Kong from 1995 to 2008

Wei NIE,Tao WANG,Aijun DING,Xuehua ZHOU,Wenxing WANG

《环境科学与工程前沿（英文）》 2014年 第8卷 第4期   页码 553-560 doi: 10.1007/s11783-013-0523-2

摘要： Toxic elements in the atmosphere can enter and accumulate in the human body, seriously impacting human health. In this study, we analyzed a 14-year (1995–2008) measurement of three toxic elements (As, Cd and Cr) in PM in Hong Kong, China. The pollution of these toxic elements in Hong Kong was not serious. The trend analysis showed that As and Cr in PM increased at a statistically significant level ( <0.05) during the 14-year period, while the Cd in PM did not change significantly. Typical seasonal variations were observed for all three toxic elements, largely in relation to the Asian monsoon. Hourly 10-day backward trajectories were computed and categorised into four groups. The continental air masses showed much higher concentrations of the three toxic elements than the marine air masses. The abundances of As and Cd in the PM were much higher in the continental air masses than those in the marine air masses, while the abundances of Cr showed an opposite pattern. The trends of the three toxic elements in East China’s air mass were consistent with those in the overall data set of Hong Kong. Examination of the toxic element data recorded at urban sites and a roadside site also indicated a large contribution of external air masses to particulate As and Cd in Hong Kong. These results suggest that the long-range transport from the mainland of China is the dominant contributor to particulate As and Cd, while both local and long-distance sources determine the particulate Cr in Hong Kong.

关键词： toxic elements     increasing trends     seasonal variations     air masses     long-distance sources    

HTML PDF 收藏

中医五脏相关学说研究——从五行到五脏相关

邓铁涛,郑洪

《中国工程科学》 2008年 第10卷 第2期   页码 7-13

摘要：

五行学说对中医学有深刻的影响，体现了传统医学重视联系、整体的特点，但五行学说本身有局限性，不能全面地反映事物间的普遍联系。中医以五脏配属五行，吸收了五行学说的精华；又根据脏腑学说的理论，在实践中超越了五行的限制。因此，中医的理论可名为“五脏相关学说”。在中医理论现代化中，可以将五脏之间的影响归纳为促进、抑制和协同3种关系，从多种角度来阐明中医的整体性与联系观。

关键词： 中医     脏腑学说     五行    

HTML PDF 收藏

Novel method of constructing generalized Hoberman sphere mechanisms based on deployment axes

Xuemin SUN, Yan-An YAO, Ruiming LI

《机械工程前沿（英文）》 2020年 第15卷 第1期   页码 89-99 doi: 10.1007/s11465-019-0567-5

摘要： This study proposes a method of constructing type II generalized angulated elements (GAEs II) Hoberman sphere mechanisms on the basis of deployment axes that intersect at one point. First, the constraint conditions for inserting GAEs II into deployment axes to form a loop are given. The angle constraint conditions of the deployment axes are obtained through a series of linear equations. Second, the connection conditions of two GAEs II loops that share a common deployable center are discussed. Third, a flowchart of constructing the generalized Hoberman sphere mechanism on the basis of deployment axes is provided. Finally, four generalized Hoberman sphere mechanisms based on a fully enclosed regular hexahedron, arithmetic sequence axes, orthonormal arithmetic sequence axes, and spiral-like axes are constructed in accordance with the given arrangement of deployment axes that satisfy the constraint conditions to verify the feasibility of the proposed method.

关键词： deployable mechanism     type II generalized angulated elements     Hoberman sphere mechanism     deployment axes     constraint conditions    

HTML PDF 收藏

Determination of mechanical parameters for elements in meso-mechanical models of concrete

Xianglin GU, Junyu JIA, Zhuolin WANG, Li HONG, Feng LIN

《结构与土木工程前沿（英文）》 2013年 第7卷 第4期   页码 391-401 doi: 10.1007/s11709-013-0225-7

摘要： The responses of cement mortar specimens of different dimensions under compression and tension were calculated based on the discrete element method with the modified-rigid-body-spring concrete model, in which the mechanical parameters derived from macro-scale material tests were applied directly to the mortar elements. By comparing the calculated results with those predicted by the Carpinteri and Weibull size effects laws, a series of formulas to convert the macro-scale mechanical parameters of mortar and interface to those at the meso-scale were proposed through a fitting analysis. Based on the proposed formulas, numerical simulation of axial compressive and tensile failure processes of concrete and cement mortar materials, respectively were conducted. The calculated results were a good match with the test results.

关键词： concrete     meso-mechanical model     discrete element method     size effect     mechanical parameter    

HTML PDF 收藏

Modeling of shear walls using finite shear connector elements based on continuum plasticity

Ulf Arne GIRHAMMAR, Per Johan GUSTAFSSON, Bo KÄLLSNER

《结构与土木工程前沿（英文）》 2017年 第11卷 第2期   页码 143-157 doi: 10.1007/s11709-016-0377-3

摘要： Light-frame timber buildings are often stabilized against lateral loads by using diaphragm action of roofs, floors and walls. The mechanical behavior of the sheathing-to-framing joints has a significant impact on the structural performance of shear walls. Most sheathing-to-framing joints show nonlinear load-displacement characteristics with plastic behavior. This paper is focused on the finite element modeling of shear walls. The purpose is to present a new shear connector element based on the theory of continuum plasticity. The incremental load-displacement relationship is derived based on the elastic-plastic stiffness tensor including the elastic stiffness tensor, the plastic modulus, a function representing the yield criterion and a hardening rule, and function representing the plastic potential. The plastic properties are determined from experimental results obtained from testing actual connections. Load-displacement curves for shear walls are calculated using the shear connector model and they are compared with experimental and other computational results. Also, the ultimate horizontal load-carrying capacity is compared to results obtained by an analytical plastic design method. Good agreements are found.

关键词： shear walls     wall diaphragms     finite element modelling     plastic shear connector     analytical modelling     experimental comparison    

HTML PDF 收藏

Modeling of dynamic response of poroelastic soil layers under wave loading

Mehmet Bar?? Can üLKER

《结构与土木工程前沿（英文）》 2014年 第8卷 第1期   页码 1-18 doi: 10.1007/s11709-014-0233-2

摘要： In this paper, the dynamic response of saturated and layered soils under harmonic waves is modeled using the finite element method. The numerical results are then verified by corresponding analytical solutions which are also developed by the author. The equations governing the dynamics of porous media are written in their fully dynamic form and possible simplifications are introduced based on the presence of inertial terms associated with solid and fluid phases. The response variations are presented in terms of pore water pressure and shear stress distributions within the layers. It is determined that a set of non-dimensional parameters and their respective ratios as a result of layering play a major role in the dynamic response.

关键词： dynamic response of soils     coupled flow-deformation     finite elements     analytical solution     harmonic waves    

HTML PDF 收藏

Release of elements from municipal solid waste incineration fly ash

Wei WANG, Lei ZHENG, Feng WANG, Xiao WAN, Keqing YIN, Xingbao GAO

《环境科学与工程前沿（英文）》 2010年 第4卷 第4期   页码 482-489 doi: 10.1007/s11783-010-0245-7

摘要： The element-release behavior of municipal solid waste incineration fly ash was explored through leaching test with continuous set-point pH (pH test) and serial single reaction cell (SSRC) tests. First, the relationship between element release and acid neutralizing capacity (ANC) consumption was examined with a pH test. Four types of release behaviors were identified which are characteristic for different elements: (1) release curves that were almost linear with ANC consumption (Ca, Zn, and Cd); (2) release that was significantly faster than ANC (Na, K, and Cl); (3) curves that featured a strong increase with ANC consumption, after a transient release, followed by an almost equal decrease (Si and S); and (4) release that is strongly retarded compared with ANC consumption (Cr, Cu, and Pb). In the SSRC system, it the existence of a pH front and a wash-out phenomenon is demonstrated. Combining the results from the SSRC test with the kinetic analysis of the ANC system in the pH test, it was inferred that less than one-third of the ANC measured from a batch pH titration plays a neutralization role in a field situation. The methodologies described may provide a powerful set of tools for systematic evaluation of element release from solid wastes.

关键词： pHstat test     Serial single reaction cell test (SSRC)     leaching     heavy metal    

HTML PDF 收藏

标题 作者 时间 类型 操作

Repeats in the transcribed regions: comprehensive characterization and comparison of

Manosh Kumar BISWAS, Christoph MAYER, Xiuxin DENG

期刊论文

Assessment of mobile and potential mobile trace elements extractability in calcareous soils using different

Mohsen Jalali, Ziba Hurseresht

期刊论文

Linking elements to outcomes of knowledge transfer in the project environment: Current review and future

期刊论文

A family of non-conforming crack front elements of quadrilateral and triangular types for 3D crack problems

Guizhong XIE, Fenglin ZHOU, Hao LI, Xiaoyu WEN, Fannian MENG

期刊论文

Assessment of leaching behavior and human bioaccessibility of rare earth elements in typical hospital

Chunfeng Wang, Guanfei Chen, Yanchen Zhu, Dan Yao, Wanfeng Wang, Lianjun Wang

期刊论文

Preconcentration of trace elements by adsorption onto a niobium wire for electrothermal atomization atomic

Satoshi KANECO, Hiroaki KITANAGA, Hideyuki KATSUMATA, Tohru SUZUKI

期刊论文

Assessment of pollution of potentially harmful elements in soils surrounding a municipal solid waste

Ying Han, Huiting Xie, Wenbin Liu, Haifeng Li, Mengjing Wang, Xuebin Chen, Xiao Liao, Nan Yan

期刊论文

Computational modeling of fracture in capsule-based self-healing concrete: A 3D study

期刊论文

A 14-year measurement of toxic elements in atmospheric particulates in Hong Kong from 1995 to 2008

Wei NIE,Tao WANG,Aijun DING,Xuehua ZHOU,Wenxing WANG

期刊论文

中医五脏相关学说研究——从五行到五脏相关

邓铁涛,郑洪

期刊论文

Novel method of constructing generalized Hoberman sphere mechanisms based on deployment axes

Xuemin SUN, Yan-An YAO, Ruiming LI

期刊论文

Determination of mechanical parameters for elements in meso-mechanical models of concrete

Xianglin GU, Junyu JIA, Zhuolin WANG, Li HONG, Feng LIN

期刊论文

Modeling of shear walls using finite shear connector elements based on continuum plasticity

Ulf Arne GIRHAMMAR, Per Johan GUSTAFSSON, Bo KÄLLSNER

期刊论文

Modeling of dynamic response of poroelastic soil layers under wave loading

Mehmet Bar?? Can üLKER

期刊论文

Release of elements from municipal solid waste incineration fly ash

Wei WANG, Lei ZHENG, Feng WANG, Xiao WAN, Keqing YIN, Xingbao GAO

期刊论文