Search | Engineering

订阅投稿

首页学术期刊学术焦点学术视频工程成就工程前沿联系我们 English

资源类型

期刊论文 115

年份

2023 1

2022 7

2021 10

2020 13

2019 8

2018 12

2017 11

2016 4

2015 7

2014 4

2013 2

2012 6

2011 3

2010 6

2009 6

2008 4

2007 2

2006 1

2005 1

2003 1

展开︾

关键词

无氢渗碳 2

3D空心结构 1

4D打印 1

PET酶 1

PET降解 1

Si/Al 比值 1

X射线自由电子激光 1

三维含孔洞结构 1

不良妊娠结局 1

中微子 1

亲钠性铋基材料 1

催化还原 1

共聚反应 1

切割效率 1

初始干密度 1

单质炸药 1

危险因素 1

双层辉光离子渗金属 1

可搜索公钥加密；带关键字搜索的无证书公钥加密；双线性对；计算性Diffie-Hellman问题 1

展开︾

检索范围：

排序：展示方式：

The Supply Chain Contract Design under Cap-and-Trade Mechanism with Free Riding

Fu-qiang Wang,Jun Liu

《工程管理前沿（英文）》 2015年第2卷第3期页码 277-286 doi: 10.15302/J-FEM-2015049

摘要： This paper studies the influence of free riding on enterprise product pricing and carbon emissions reduction investment, as well as the contract design to achieve supply chain coordination under the carbon trading mechanism. First, we discuss the situation where carbon emissions reduction investment affects the product price and income. It demonstrates that the optimal investment of the upstream manufacturer increases with the degree of the free riding of the downstream manufacturer. The upstream manufacturer can improve their carbon reduction investment and the whole supply chain achieves Pareto improvement when the investment cost sharing contract is introduced. Nevertheless, under the cost-sharing contract the optimal investment of the decentralized supply chain is still lower than that of the centralized supply chain, and only in some particular cases can the two types of supply chain achieve equal total profits. Then, we preliminarily explore the situation where the product price and income is influenced by carbon emissions reduction investment. The consequences indicate that the optimal investment of the upstream manufacturers in this situation is less than the former one’s, and the transfer payment mechanism is able to improve the level of the supply chain overall carbon emissions-reduction. Moreover, compared to the former situation, the effects of free riding of the downstream manufacturer are even more serious. The conclusions can provide some intellectual support for manufacturing enterprises to make reasonable emissions reduction strategies and coordinate the supply chain existing in free riding.

关键词： carbon emissions reduction free riding supply chain contract design cap-and-trade

HTML PDF 收藏

Cell-free systems in the new age of synthetic biology

Fernando Villarreal,Cheemeng Tan

《化学科学与工程前沿（英文）》 2017年第11卷第1期页码 58-65 doi: 10.1007/s11705-017-1610-x

摘要： The advent of synthetic biology has ushered in new applications of cell-free transcription-translation systems. These cell-free systems are reconstituted using cellular proteins, and are amenable to modular control of their composition. Here, we discuss the historical advancement of cell-free systems, as well as their new applications in the rapid design of synthetic genetic circuits and components, directed evolution of biomolecules, diagnosis of infectious diseases, and synthesis of vaccines. Finally, we present our vision on the future direction of cell-free synthetic biology.

关键词： cell-free system application

HTML PDF 收藏

Decontamination of Cr(VI) facilitated formation of persistent free radicals on rice husk derived biochar

Kaikai Zhang, Peng Sun, Yanrong Zhang

《环境科学与工程前沿（英文）》 2019年第13卷第2期 doi: 10.1007/s11783-019-1106-7

摘要：

PFRs were produced on biochar during Cr(VI) decontamination.

PFRs formation on biochar was owing to the oxidization of phenolic-OH by Cr(VI).

Appearance of excessive oxidant led to the consumption of PFRs on biochar.

Biochar charred at high temperature possessed great performance to Cr(VI) removal.

关键词： Biochar Persistent free radicals Phenolic hydroxyl groups Cr(VI) reduction

HTML PDF 收藏

Thermoresponsive block copolymer supported Pt nanocatalysts for base-free aerobic oxidation of 5-hydroxymethyl

《化学科学与工程前沿（英文）》 2021年第15卷第6期页码 1514-1523 doi: 10.1007/s11705-021-2092-4

摘要： A base-free catalytic system for the aerobic oxidation of 5-hydroxymethyl-2-furfural was exploited by using Pt nanoparticles immobilized onto a thermoresponsive poly(acrylamide-co-acrylonitrile)-b-poly(N-vinylimidazole) block copolymer, with an upper critical solution temperature of about 45 °C. The Pt nanocatalysts were well-dispersed and highly active for the base-free oxidation of 5-hydroxymethyl-2-furfural by molecular oxygen in water, affording high yields of 2,5-furandicarboxylic acid (up to>99.9%). The imidazole groups in the block copolymer were conducive to the improvement of catalytic performance. Moreover, the catalysts could be easily separated and recovered based on their thermosensitivity by cooling the reaction system below the upper critical solution temperature. Good stability and reusability were observed over these copolymer-immobilized catalysts with no obvious decrease in catalytic activity in the five consecutive cycles.

关键词： aerobic oxidation base-free 5-hydroxymethyl-2-furfural Pt nanoparticle thermoresponsive block copolymer

HTML PDF 收藏

Hollow carbon spheres and their noble metal-free hybrids in catalysis

《化学科学与工程前沿（英文）》 2021年第15卷第6期页码 1380-1407 doi: 10.1007/s11705-021-2097-z

摘要： Hollow carbon spheres have garnered great interest owing to their high surface area, large surface-to-volume ratio and reduced transmission lengths. Herein, we overview hollow carbon sphere-based materials and their noble metal-free hybrids in catalysis. Firstly, we summarize the key fabrication techniques for various kinds of hollow carbon spheres, with a particular emphasis on controlling pore structure and surface morphology, and then heterogeneous doping as well as their metal-free/containing hybrids are presented; next, possible applications for non-noble metal/hollow carbon sphere hybrids in the area of energy-related catalysis, including oxygen reduction reaction, hydrogen evolution reaction, oxygen evolution reaction, water splitting, rechargeable Zn-air batteries and pollutant degradation are discussed; finally, we introduce the various challenges and opportunities offered by hollow carbon spheres from the perspective of synthesis and catalysis.

关键词： hollow carbon spheres functionalization noble metal-free catalysis

HTML PDF 收藏

Design approach for single piston hydraulic free piston diesel engines

Wei WU, Shihua YUAN, Jibin HU, Chongbo JING,

《机械工程前沿（英文）》 2009年第4卷第4期页码 371-378 doi: 10.1007/s11465-009-0069-y

摘要： The operating characteristics of a single piston hydraulic free piston diesel engine differ significantly from conventional diesel engines and this provides a theoretical basis for controlling and optimizing the design of the engine. The design of the proposed engine intended as a power supply for a hydraulic propulsion vehicle is presented. An engine performance forecast model was generated in AMESim. The performance of the prototype engine is predicted and the predictive results are verified with experiments. The particular features of the engine are discussed. The dynamic characteristics of the prototype engine are analyzed and the results indicate the rationality and feasibility of the engine design parameters. The features of the controllable working frequency and the intermittence output flows are provided. The flow capacity characteristics of the hydraulic valves on the prototype engine are offered. The methods for starting and the operation after misfire are presented.

关键词： free piston engine (FPE) diesel engine hydraulic equipment simulation experiment

HTML PDF 收藏

Highly selective detection of copper(II) by a “ligand-free” conjugated copolymer in nucleophilic solvents

Weixing Deng, Pengfei Sun, Quli Fan, Lei Zhang, Tsuyoshi Minami

《化学科学与工程前沿（英文）》 2020年第14卷第1期页码 105-111 doi: 10.1007/s11705-019-1791-6

摘要： The synthesis of -cyclohexyl carbamate-attached fluorene- -phenylene copolymer (PFPNCC) and the use of PFPNCC as a “ligand-free” fluorescent chemosensor for Cu(II) are described. Addition of Cu(II) can efficiently quench the fluorescence of PFPNCC in nucleophilic solvents such as DMF and DMSO, but not in low nucleophilic solvents such as 1,4-dioxane and THF. Ultraviolet-visible spectra of the mixture of the conjugated polymer and Cu(II) indicate the presence of a reduced Cu(I) ion in the solution. Furthermore, fluorescence recovery of PFPNCC observed at low temperature suggests that the quenching and reducing mechanism is most probably due to a photo-induced electron transfer from excited PFPNCC to Cu(II). Our findings provide a novel strategy for highly selective conjugated polymer-based chemosensors for various target analytes, albeit “ligand-free”.

关键词： ligand-free fluorescent chemosensor copper photo-induced electron transfer

HTML PDF 收藏

Influence of the filler materials on flux-free brazing of pure aluminium (1050)

Kirsten BOBZIN, Lidong ZHAO, Thomas SCHLAEFER, Thomas WARDA,

《机械工程前沿（英文）》 2010年第5卷第1期页码 47-51 doi: 10.1007/s11465-009-0079-9

摘要： In the present study, samples of pure aluminium (1050) were deposited by cold spraying with filler materials such as Al12Si, Al7Si, Al12Si-4%Cu, and the Al-Si-based filler material A, which was especially developed for flux-free brazing by the Surface Engineering Institute. Besides, pure Si powder was also sprayed. The coated samples were heat-treated under different conditions and were brazed under an argon atmosphere without fluxes or with the flux Nokolok by an induction heating system. The shear strength of the brazed joints was determined. The results show that the filler materials could be well deposited by cold spraying. A thin layer of brittle Si could also form due to the strong deformation of the substrate surface. The heat treatments showed that a very good metallurgical bond between the filler materials and the substrate could be realized by the deposition by cold spraying. The Al7Si deposited samples could not be brazed without fluxes under the given conditions. The samples deposited with other filler materials could be brazed without fluxes. The in-situ diffusion process made it possible to braze the Si-deposited samples at 580°C. The joints of the samples deposited with the filler material showed the highest shear strength of 41 MPa, whereas the values of the Al12Si and Si deposited samples were less than 20 MPa. The employment of the flux Nikolok significantly increased the shear strength of the Al12Si deposited samples to more than 53 MPa.

关键词： aluminium flux-free brazing cold spraying shear strength

HTML PDF 收藏

Solvent-free mechanochemical mild oxidation method to enhance adsorption properties of chitosan

《环境科学与工程前沿（英文）》 2021年第15卷第6期 doi: 10.1007/s11783-021-1416-4

摘要：

• Solvent-free chitosan oxidation is obtained by rapid mechanochemical reaction.

关键词： Chitosan High energy ball milling Mechanochemistry Oxidation

HTML PDF 收藏

“ALL FREE” — a novel design concept of applying partial oxidation process to vehicle

Ling LIN, Wenshuang LIN, Qingbiao LI, Yao ZHOU,

《化学科学与工程前沿（英文）》 2010年第4卷第2期页码 207-212 doi: 10.1007/s11705-009-0240-3

摘要： With the rapid expansion of the global motor vehicle population, the transportation sector has taken up a growing proportion among all the carbon dioxide emission-related sectors. To contribute to solutions of the carbon dioxide-oriented problem in transportation, this paper proposes the “ALL FREE” concept that applies partial oxidation process instead of the conventional complete oxidation to vehicle engines. In such an engine, the fuels are partially oxidized into corresponding chemical products, which, as a result, enable the process to be theoretically free of CO, while the heat output of the partial oxidation could drive the vehicle. On the other hand, the resulting products are of great value, which could decrease or even counteract the cost of fuels in transportation. In this paper, the thermodynamic and kinetic data (e.g., the heat output and heat release rate) of five selected partial oxidation reactions were calculated at length to demonstrate and exemplify the theoretical feasibility of the “ALL FREE” concept. It turned out that the partial oxidation of -butane to maleic anhydride has the most potential to meet the basic requirements of this concept. To sum up, this design concept is of significant application potential for the reduction of CO emissions in the transportation industry, although there remain many technical challenges.

关键词： oxidation process CO complete oxidation ALL FREE -butane

HTML PDF 收藏

Optimization of pretreatment of Jatropha oil with high free fatty acids for biodiesel production

Supriyono SUWITO, Giuliano DRAGONE, Hary SULISTYO, Bardi MURACHMAN, Suryo PURWONO, José TEIXEIRA

《化学科学与工程前沿（英文）》 2012年第6卷第2期页码 210-215 doi: 10.1007/s11705-012-1282-5

摘要： A central composite rotatable design and response surface methodology were used in order to investigate the individual and combined effects of the ethanol-to-oil ratio, H SO concentration, temperature and time of reaction on the reduction of free fatty acid (FFA) in jatropha oil. A quadratic polynomial model relating the reaction variables with FFA reduction was developed, presenting a good coefficient of determination ( = 0.893). For reducing FFA to less than 1%, the optimal combination was found to be 0.62 v·v ethanol-to-oil ratio (14.9 v·v ethanol-to-FFA ratio), 1.7% v·v H SO concentration, and 79 min reaction time at a reaction temperature of 54°C. These results are of great relevance to maximize methyl esters formation by transesterification using an alkaline catalyst.

关键词： biodiesel biofuel esterification free fatty acids jatropha curcas oil

HTML PDF 收藏

Semi-analytical approach for free vibration analysis of cracked beams resting on two-parameter elastic

null

《机械工程前沿（英文）》 2014年第9卷第2期页码 191-202 doi: 10.1007/s11465-014-0293-y

摘要：

In present study, free vibration of cracked beams resting on two-parameter elastic foundation with elastically restrained ends is considered. Euler-Bernoulli beam hypothesis has been applied and translational and rotational elastic springs in each end considered as support. The crack is modeled as a mass-less rotational spring which divides beam into two segments. After governing the equations of motion, the differential transform method (DTM) has been served to determine dimensionless frequencies and normalized mode shapes. DTM is a semi-analytical approach based on Taylor expansion series that converts differential equations to recursive algebraic equations. The DTM results for the natural frequencies in special cases are in very good agreement with results reported by well-known references. Also, the DTM procedure yields rapid convergence beside high accuracy without any frequency missing. Comprehensive studies to analyze the effects of crack location, crack severity, parameters of elastic foundation and boundary conditions on dimensionless frequencies as well as effects of elastic boundary conditions on cracked beams mode shapes are carried out and some problems handled for first time in this paper. Since this paper deals with general problem, the derived formulation has capability for analyzing free vibration of cracked beam with every boundary condition.

关键词： free vibration cracked beam elastic foundation restrained ends differential transform method

HTML PDF 收藏

Comparing the effects of Bassini versus tension-free hernioplasty: 3 years’ follow-up

Yulong SHI, Zhongxue SU, Leping LI, Hongjun LIU, Changqing JING,

《医学前沿（英文）》 2010年第4卷第4期页码 463-468 doi: 10.1007/s11684-010-0050-5

摘要： In order to compare the effects of Bassini and tension-free mesh hernioplasty, a total of 552 patients with inguinal hernia who were subjected to surgical treatment in our hospital were randomly divided into the following two groups: the Bassini group (=269) and the tension-free mesh group (=283). The recurrence rates, pain, discomfort, and other complications were recorded, and the causes of the complications were explored. The recurrence rate in the Bassini group was 8.9% (24/269), significantly higher than that in the tension-free repair group (2.8%, 8/283). In addition, the recurrence rates in the Bassini and tension-free groups before 2004 were 12.6% and 5.6%, respectively, which were markedly higher than the rates after 2004 (5.3% and 0.7%, respectively). The rate of post-operative discomfort and pain within the first three months was higher in the Bassini group compared to the tension-free group (25.7% 18.5%, respectively). However, there was no difference after three months in the rate of post-operative discomfort and pain, incidence of infection, or scrotal edema between the two groups. The average hospital stay in the Bassini group was longer than that in the tension-free repair group (7.6€±€1.2 4.5€±€2.2 days, respectively), but the cost was lower (4518.0€±€510 6221.3€±€578 yuan, respectively). Thus, tension-free mesh hernioplasty is indicated for most inguinal hernia patients due to the low recurrence rate, rapid recovery time, and treatment success, but the traditional Bassini procedure has lower cost and other beneficial effects and is still suitable for some patients.

关键词： hernioplasty Bassini repair tension-free repair complication

HTML PDF 收藏

Metal-free, carbon-based catalysts for oxygen reduction reactions

Zhiyi Wu,Zafar Iqbal,Xianqin Wang

《化学科学与工程前沿（英文）》 2015年第9卷第3期页码 280-294 doi: 10.1007/s11705-015-1524-4

摘要： Developing metal-free, carbon-based catalysts to replace platinum-based catalysts for oxygen reduction reactions (ORRs) is an emerging area of research. In recent years, different carbon structures including carbon doped with IIIA-VIIA heteroatoms (C−M site-based, where M represents the doped heteroatom) and polynitrogen (PN) compounds encapsulated in carbon nanotubes (CNTs) (N−N site-based) have been synthesized. Compared to metallic catalysts, these materials are highly active, stable, inexpensive, and environmentally friendly. This review discusses the development of these materials, their ORR performances and the mechanisms for how the incorporation of heteroatoms enhances the ORR activity. Strategies for tailoring the structures of the carbon substrates to improve ORR performance are also discussed. Future studies in this area will need to include optimizing synthetic strategies to control the type, amount and distribution of the incorporated heteroatoms, as well as better understanding the ORR mechanisms in these catalysts.

关键词： oxygen reduction reaction electrocatalysis metal-free carbon-based polynitrogen