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Structural behavior of intermediate length cold-formed steel rack columns with C-stitches

M. ANBARASU, Mahmud ASHRAF

《结构与土木工程前沿(英文)》 2019年 第13卷 第4期   页码 937-949 doi: 10.1007/s11709-019-0528-4

摘要: This article presents an experimental and numerical investigation on the strength and performance of intermediate length rack column sections with C-stitches under axial compression. The test program consisted of 10 axial concentric compression tests on columns with and without C-stitches under pin end conditions for two different geometric lengths. Finite element (FE) models were developed using commercial FE package ABAQUS considering material and geometric nonlinearities as well as initial geometric imperfections. The elastic buckling properties of the section were calculated using readily available linear elastic buckling analysis tools based on Generalized Beam Theory (GBT) and Finite Strip Method (FSM). Obtained FE results were compared with those obtained experimentally, and once verified the developed FE modeling technique was used to carry out a parametric study to examine changes in structural response due to variations in length, depth and spacing of C-stitches. Observed influences of C-stitches on the behavior and resistance of the considered columns were carefully analyzed, and key design aspects are presented herein.

关键词: cold-formed steel columns     C-stitches     intermediate length columns     distortional buckling    

Valveless pumping using a two-stage impedance pump

C.-C. LEE, Y. A. ABAKR, K.-C. WOO

《机械工程前沿(英文)》 2013年 第8卷 第3期   页码 311-318 doi: 10.1007/s11465-013-0270-x

摘要:

Impedance pump is defined as a type of valveless pumping mechanism, where an elastic tube is joined with a tube of different impedance, a periodic asymmetrical compression on part of the elastic tube will produce a unidirectional flow. Numerical and experimental studies had been conducted in the past, but little experimental work was found to exploit the principle of multi-stage impedance pumping for fluid transportation. This paper concentrates on the fluid behavior for an open-loop two-stage system experimentally. The aim of this work is to have an insight on the deliverable head and pumping rate of an open-loop two-stage impedance pumping system. This paper generally investigates the effect of different parameters towards the generation of unidirectional flows and composite flow of two opposite directions. Results obtained are of significant values.

关键词: valveless pumping     open-loop     two-stage     unidirectional     composite    

基于S3C2410的GPRS数据终端的设计

孙学用

《中国工程科学》 2007年 第9卷 第12期   页码 94-96

摘要: 提出了以S3C2410处理器为核心,以SIM100-E为GPRS通信模块,构建了一套嵌入式Internet数据终端的方案,对其硬件构成及工作流程进行了讨论,描述了其软件层次结构,并详细讲解了基于该平台的

关键词: GPRS;嵌入式Internet;S3C2410;SIM100-E    

Bioinspired C/TiO

Jian LI, Likun GAO, Wentao GAN

《农业科学与工程前沿(英文)》 2017年 第4卷 第4期   页码 459-464 doi: 10.15302/J-FASE-2017178

摘要: butterfly wings were replicated by a sol-gel method and a calcination process, which could take advantage of the spatial features of the wing to enhance their photocatalytic properties. Hierarchical structures of -carbon-TiO (PP-C-TiO ) were confirmed by SEM observations. By applying the Brunauer-Emmett-Teller method, it was concluded that in the presence of wings the product shows higher surface area with respect to the pure TiO made in the absence of the wings. The higher specific surface area is also beneficial for the improvement of photocatalytic property. Furthermore, the conduction and valence bands of the PP-C-TiO are more negative than the corresponding bands of pure TiO , allowing the electrons to migrate from the valence band to the conduction band upon absorbing visible light. That is, the presence of C originating from wings in the PP-C-TiO could extend the photoresponsiveness to visible light. This strategy provides a simple method to fabricate a high-performance photocatalyst, which enables the simultaneous control of the morphology and carbon element doping.

关键词: bioinspired     butterfly wings     C/TiO2     photocatalyst     visible light    

Antithrombin deficiency and decreased protein C activity in a young man with venous thromboembolism:

null

《医学前沿(英文)》 2018年 第12卷 第3期   页码 319-323 doi: 10.1007/s11684-017-0553-4

摘要:

Antithrombin and protein C are two crucial members in the anticoagulant system and play important roles in hemostasis. Mutations in and lead to deficiency or dysfunction of the two proteins, which could result in venous thromboembolism (VTE). Here, we report a Chinese 22-year-old young man who developed recurrent and serious VTE in cerebral veins, visceral veins, and deep veins of the lower extremity. Laboratory tests and direct sequencing of and were conducted for the patient and his family members. Coagulation tests revealed that the patient presented type I antithrombin deficiency combined with decreased protein C activity resulting from a small insertion mutation c.848_849insGATGT in and a short deletion variant c.572_574delAGA in . This combination of the two mutations was absent in 400 healthy subjects each from southern and northern China. Then, we summarized all the mutations of the and gene reported in the Chinese Han population. This study demonstrates that the combination of antithrombin deficiency and decreased protein C activity can result in severe VTE and that the coexistence of different genetic factors may increase the risk of VTE.

关键词: antithrombin deficiency     protein C activity     mutation     variant     venous thromboembolism     anticoagulants    

Atomistic simulations of plasma catalytic processes

Erik C. Neyts

《化学科学与工程前沿(英文)》 2018年 第12卷 第1期   页码 145-154 doi: 10.1007/s11705-017-1674-7

摘要: There is currently a growing interest in the realisation and optimization of hybrid plasma/catalyst systems for a multitude of applications, ranging from nanotechnology to environmental chemistry. In spite of this interest, there is, however, a lack in fundamental understanding of the underlying processes in such systems. While a lot of experimental research is already being carried out to gain this understanding, only recently the first simulations have appeared in the literature. In this contribution, an overview is presented on atomic scale simulations of plasma catalytic processes as carried out in our group. In particular, this contribution focusses on plasma-assisted catalyzed carbon nanostructure growth, and plasma catalysis for greenhouse gas conversion. Attention is paid to what can routinely be done, and where challenges persist.

关键词: atomic scale simulation     plasma-catalyst    

Elevated C-reactive protein levels predict worsening prognosis in Chinese patients with first-onset stroke

Jiangtao YAN, Rutai HUI, Daowen WANG

《医学前沿(英文)》 2009年 第3卷 第1期   页码 30-35 doi: 10.1007/s11684-009-0005-x

摘要: The role of high sensitivity C-reactive protein (hsCRP) in predicting prognosis after stroke in the Asian population has not been investigated. We hypothesized that elevated levels of hsCRP were associated with worsening prognosis after stroke in Chinese patients. Two hundred and ninety consecutive patients with first-onset stroke and 290 age- and gender-matched control subjects without any cerebrovascular disease were enrolled for study. Plasma hsCRP level was detected and subsequent vascular events and death were recorded in both groups over a 5-year period. Compared to control group, patients presenting with stroke had higher plasma hsCRP level (3.3 ± 3.8 1.3 ± 2.2 mg/L, < 0.01). Furthermore, in the group of patients with stroke, the mean plasma hsCRP level was higher in patients who developed subsequent vascular diseases or died as compared with the patients without further complications (4.4 ± 4.3 2.7 ± 3.3 mg/L, < 0.01). Compared to the lowest tertile of hsCRP level, the relative risk for vascular events or death in stroke patients was 2.91 in the highest tertile of hsCRP (95% CI, 1.54–5.50, = 0.001). This increase in relative risk for vascular events or death in stroke patients continued after adjustment for age, sex and other cardiovascular risk factors such as hypertension and diabetes ( : 2.771, 95% CI: 1.367–5.617, = 0.005). These findings indicate that increased hsCRP level is associated with worsening prognosis after stroke in Chinese patients and suggests that inflammation is correlated with stroke outcome.

关键词: C-reactive protein     inflammation     stroke    

A simple, azulene-based colorimetric probe for the detection of nitrite in water

Lloyd C. Murfin, Carlos M. López-Alled, Adam C. Sedgwick, Jannis Wenk, Tony D. James, Simon E. Lewis

《化学科学与工程前沿(英文)》 2020年 第14卷 第1期   页码 90-96 doi: 10.1007/s11705-019-1790-7

摘要: We describe the synthesis and evaluation of an azulene-based chemodosimeter for nitrite. The probe was found to undergo two distinct color changes upon introduction aqueous nitrite ion. A near-instant formation of a grey color provides a qualitative indication of the presence of nitrite, followed by the formation of a deep-yellow/orange color, the endpoint from which quantitative data can be derived. The azulene probe exhibits 1:1 stoichiometry of reaction with nitrite in water, and is selective for nitrite over other anions. The azulene probe was applied to determine nitrite content in cured meat, and compared with the British Standard testing procedure (Griess test). The value obtained from the azulene-based probe agreed closely with the standard test. Our procedure only requires the preparation of one standard solution, instead of the three required for the standard Griess test.

关键词: azulene     nitrite     diazoquinone    

Comments on the special issue of

Neil C. TURNER

《农业科学与工程前沿(英文)》 2017年 第4卷 第2期   页码 254-255 doi: 10.15302/J-FASE-2017156

Comments on the special issue on tropical crops of

Luiz J C B CARVALHO

《农业科学与工程前沿(英文)》 2016年 第3卷 第4期   页码 375-376 doi: 10.15302/J-FASE-2016129

Enhancing the efficiency of nitrogen removing bacterial population to a wide range of C:N ratio (1.5:1 to 14:1) for simultaneous C & N removal

《环境科学与工程前沿(英文)》 2022年 第16卷 第8期 doi: 10.1007/s11783-022-1522-y

摘要:

• Simultaneous C & N removal in Methammox occurs at wide C:N ratio.

关键词: Methanogens     Biological Nitrogen Removal (BNR)     Simultaneous     Methammox     C:N ratio    

Uncertainty propagation analysis by an extended sparse grid technique

JIA, C. JIANG, C. M. FU, B. Y. NI, C. S. WANG, M. H. PING

《机械工程前沿(英文)》 2019年 第14卷 第1期   页码 33-46 doi: 10.1007/s11465-018-0514-x

摘要: In this paper, an uncertainty propagation analysis method is developed based on an extended sparse grid technique and maximum entropy principle, aiming at improving the solving accuracy of the high-order moments and hence the fitting accuracy of the probability density function (PDF) of the system response. The proposed method incorporates the extended Gauss integration into the uncertainty propagation analysis. Moreover, assisted by the Rosenblatt transformation, the various types of extended integration points are transformed into the extended Gauss-Hermite integration points, which makes the method suitable for any type of continuous distribution. Subsequently, within the sparse grid numerical integration framework, the statistical moments of the system response are obtained based on the transformed points. Furthermore, based on the maximum entropy principle, the obtained first four-order statistical moments are used to fit the PDF of the system response. Finally, three numerical examples are investigated to demonstrate the effectiveness of the proposed method, which includes two mathematical problems with explicit expressions and an engineering application with a black-box model.

关键词: uncertainty propagation analysis     extended sparse grid     maximum entropy principle     extended Gauss integration     Rosenblatt transformation     high-order moments analysis    

A density functional theory study of methane activation on MgO supported NiM cluster: role of M on C–H

《化学科学与工程前沿(英文)》 2022年 第16卷 第10期   页码 1485-1492 doi: 10.1007/s11705-022-2169-8

摘要: Methane activation is a pivotal step in the application of natural gas converting into high-value added chemicals via methane steam/dry reforming reactions. Ni element was found to be the most widely used catalyst. In present work, methane activation on MgO supported Ni–M (M = Fe, Co, Cu, Pd, Pt) cluster was explored through detailed density functional theory calculations, compared to pure Ni cluster. CH4 adsorption on Cu promoted Ni cluster requires overcoming an energy of 0.07 eV, indicating that it is slightly endothermic and unfavored to occur, while the adsorption energies of other promoters M (M = Fe, Co, Pd and Pt) are all higher than that of pure Ni cluster. The role of M on the first C–H bond cleavage of CH4 was investigated. Doping elements of the same period in Ni cluster, such as Fe, Co and Cu, for C–H bond activation follows the trend of the decrease of metal atom radius. As a result, Ni–Fe shows the best ability for C–H bond cleavage. In addition, doping the elements of the same family, like Pd and Pt, for CH4 activation is according to the increase of metal atom radius. Consequently, C–H bond activation demands a lower energy barrier on Ni–Pt cluster. To illustrate the adsorptive dissociation behaviors of CH4 at different Ni–M clusters, the Mulliken atomic charge was analyzed. In general, the electron gain of CH4 binding at different Ni–M clusters follows the sequence of Ni–Cu (–0.02 e) < Ni (–0.04 e) < Ni–Pd (–0.08 e) < Ni–Pt (–0.09 e) < Ni–Co (–0.10 e) < Ni–Fe (–0.12 e), and the binding strength between catalysts and CH 4 raises with the CH4 electron gain increasing. This work provides insights into understanding the role of promoter metal M on thermal-catalytic activation of CH4 over Ni/MgO catalysts, and is useful to interpret the reaction at an atomic scale.

关键词: CH4 dissociation     Ni–M     C–H bond activation     charge transfer    

Modeling of alkali-silica reaction in concrete: a review

WANG, Q.C. SUN, C.H. ZHANG, D.R.J. OWEN

《结构与土木工程前沿(英文)》 2012年 第6卷 第1期   页码 1-18 doi: 10.1007/s11709-012-0141-2

摘要: This paper presents a comprehensive review of modeling of alkali-silica reaction (ASR) in concrete. Such modeling is essential for investigating the chemical expansion mechanism and the subsequent influence on the mechanical aspects of the material. The concept of ASR and the mechanism of expansion are first outlined, and the state-of-the-art of modeling for ASR, the focus of the paper, is then presented in detail. The modeling includes theoretical approaches, meso- and macroscopic models for ASR analysis. The theoretical approaches dealt with the chemical reaction mechanism and were used for predicting pessimum size of aggregate. Mesoscopic models have attempted to explain the mechanism of mechanical deterioration of ASR-affected concrete at material scale. The macroscopic models, chemo-mechanical coupling models, have been generally developed by combining the chemical reaction kinetics with linear or nonlinear mechanical constitutive, and were applied to reproduce and predict the long-term behavior of structures suffering from ASR. Finally, a conclusion and discussion of the modeling are given.

关键词: alkali-silica reaction (ASR)     modeling     concrete     mesoscopic     macroscopic    

Special issue on “Fluorescent probes”

Adam C. Sedgwick, Tony D. James

《化学科学与工程前沿(英文)》 2020年 第14卷 第1期   页码 1-3 doi: 10.1007/s11705-019-1910-4

标题 作者 时间 类型 操作

Structural behavior of intermediate length cold-formed steel rack columns with C-stitches

M. ANBARASU, Mahmud ASHRAF

期刊论文

Valveless pumping using a two-stage impedance pump

C.-C. LEE, Y. A. ABAKR, K.-C. WOO

期刊论文

基于S3C2410的GPRS数据终端的设计

孙学用

期刊论文

Bioinspired C/TiO

Jian LI, Likun GAO, Wentao GAN

期刊论文

Antithrombin deficiency and decreased protein C activity in a young man with venous thromboembolism:

null

期刊论文

Atomistic simulations of plasma catalytic processes

Erik C. Neyts

期刊论文

Elevated C-reactive protein levels predict worsening prognosis in Chinese patients with first-onset stroke

Jiangtao YAN, Rutai HUI, Daowen WANG

期刊论文

A simple, azulene-based colorimetric probe for the detection of nitrite in water

Lloyd C. Murfin, Carlos M. López-Alled, Adam C. Sedgwick, Jannis Wenk, Tony D. James, Simon E. Lewis

期刊论文

Comments on the special issue of

Neil C. TURNER

期刊论文

Comments on the special issue on tropical crops of

Luiz J C B CARVALHO

期刊论文

Enhancing the efficiency of nitrogen removing bacterial population to a wide range of C:N ratio (1.5:1 to 14:1) for simultaneous C & N removal

期刊论文

Uncertainty propagation analysis by an extended sparse grid technique

JIA, C. JIANG, C. M. FU, B. Y. NI, C. S. WANG, M. H. PING

期刊论文

A density functional theory study of methane activation on MgO supported NiM cluster: role of M on C–H

期刊论文

Modeling of alkali-silica reaction in concrete: a review

WANG, Q.C. SUN, C.H. ZHANG, D.R.J. OWEN

期刊论文

Special issue on “Fluorescent probes”

Adam C. Sedgwick, Tony D. James

期刊论文