资源类型

期刊论文 431

年份

2023 3

2022 23

2021 46

2020 46

2019 43

2018 36

2017 36

2016 34

2015 36

2014 16

2013 22

2012 11

2011 10

2010 18

2009 16

2008 8

2007 10

2006 2

2005 5

2004 2

展开 ︾

关键词

人工智能 2

人工神经网络 2

单克隆抗体 2

岩爆 2

强震发生断层 2

/III-V界面 1

1860 MPa等级 1

2R-1C模型；嵌入式系统；参数估计；非迭代方法；二次型 1

300 M钢 1

32 m箱梁 1

4250 m 1

700 m跨径级别 1

9 %~12 % Cr 钢 1

&prime 1

&gamma 1

Al2O3-MxOy 1

BALB/C小鼠 1

CCUS 1

COVID-19 1

展开 ︾

检索范围：

排序： 展示方式：

针对Wimax中多用户的考虑状态转移损失的省电算法 Article

Bo LI,Sung-kwon PARK

《信息与电子工程前沿（英文）》 2016年 第17卷 第10期   页码 1085-1094 doi: 10.1631/FITEE.1500314

摘要： 概要：在IEEE 802.16e/m标准中，为了节省移动台（mobile subscriber station, MSS）的电量，定义了三种省电类型（power saving classes, PSC）

关键词： 省电类型；状态转变损失；IEEE 802.16e/m；服务质量    

HTML PDF 收藏
分享

基于最小速率保证的IEEE 802-16e公平调度算法

史俊财,胡爱群,关艳峰

《中国工程科学》 2008年 第10卷 第2期   页码 54-59

摘要：

针对IEEE 802-16e协议的特点，提出了一种基于最小速率保证的IEEE 802-16e 公平 调度（MTRFS）算法。

关键词： IEEE 802-16e     调度算法     QoS     公平    

HTML PDF 收藏
分享

基于多跳双向认证的802.16Mesh网络SA管理机制

王兴建,胡爱群,黄玉划

《中国工程科学》 2006年 第8卷 第9期   页码 69-73

摘要：

IEEE802.16-2004无线城域网（wireless-MAN）标准支持的多跳（Mesh）网络是一种树状网络和adhoc网络结合的新型网络。

关键词： IEEE80216     Mesh     节点     多跳双向认证     修正路由    

HTML PDF 收藏
分享

包容性工程——借助工程技术发明为身体或精神障碍人士赋能

Cummings, Philippe M. Fauchet, Michael Goldfarb, Martha W.M. Jones, Maithilee Kunda, Jonathan B.Stassun, Zachary E. Warren, Karl E. Zelik

《工程（英文）》 2021年 第7卷 第2期   页码 141-143 doi: 10.1016/j.eng.2020.06.020

HTML PDF 收藏
分享

Performance, emission and combustion characteristics of CI engine fuelled with diesel and hydrogen

Senthil KUMAR,M. LOGANATHAN,E. James GUNASEKARAN

《能源前沿（英文）》 2015年 第9卷 第4期   页码 486-494 doi: 10.1007/s11708-015-0368-4

摘要： Hydrogen (H ) is being considered as a primary automotive fuel and as a replacement for conventional fuels. Some of the desirable properties, like high flame velocity, high calorific value motivate us to use hydrogen fuel as a dual fuel mode in diesel engine. In this experiment, hydrogen was inducted in the inlet manifold with intake air. The experiments were conducted on a four stroke, single cylinder, water cooled, direct injection (DI), diesel engine at a speed of 1500 r/min. Hydrogen was stored in a high pressure cylinder and supplied to the inlet manifold through a water-and-air-based flame arrestor. A pressure regulator was used to reduce the cylinder pressure from 140 bar to 2 bar. The hydrogen was inducted with a volume flow rate of 4l pm, 6l pm and 8l pm, respectively by a digital volume flow meter. The engine performance, emission and combustion parameters were analyzed at various flow rates of hydrogen and compared with diesel fuel operation. The brake thermal efficiency (BTE) was increased and brake specific fuel consumption (BSFC) decreased for the hydrogen flow rate of 8l pm as compared to the diesel and lower volume flow rates of hydrogen. The hydrocarbon (HC) and carbon monoxide (CO) were decreased and the oxides of nitrogen (NO ) increased for higher volume flow rates of hydrogen compared to diesel and lower volume flow rates of hydrogen. The heat release rate and cylinder pressure was increased for higher volume flow rates of hydrogen compared to diesel and lower volume flow rates of hydrogen.

关键词： hydrogen     brake thermal efficiency     crank angle     compressed ignition (CI)    

HTML PDF 收藏
分享

使用IEEE 2030.5 标准在电网边缘进行可交易需求响应操作 Article

Javad Fattahi, Mikhak Samadi, Melike Erol-Kantarci, Henry Schriemer

《工程（英文）》 2020年 第6卷 第7期   页码 801-811 doi: 10.1016/j.eng.2020.06.005

摘要： 完整的基于实验室的实施（据我们所知）首次实现了全面的TDR案例，该案例完全符合电气与电子工程师协会（IEEE）2030.5标准，解决了网络安全智能能源规范（SEP）应用协议的互操作性。基于在较长时间内获取的一组智能电表数据，我们参与了多个TDR场景，并通过符合IEEE 2030.5标准的全功能实现证明了我们的方案可以在现实条件下将网络峰值功耗降低22%。

关键词： 可交易需求响应     IEEE 2030.5     智能电网     多代理系统     邻域协调    

HTML PDF 收藏
分享

Oxidative leaching kinetics of molybdenum-uranium ore in H

Lasheen, M. E. El-Ahmady, H. B. Hassib, A. S. Helal

《化学科学与工程前沿（英文）》 2013年 第7卷 第1期   页码 95-102 doi: 10.1007/s11705-013-1317-6

摘要： The processing of molybdenum-uranium ore in a sulfuric acid solution using hydrogen peroxide as an oxidant has been investigated. The leaching temperature, hydrogen peroxide concentration, sulfuric acid concentration, leaching time, particle size, liquid-to-solid ratio and agitation speed all have significant effects on the process. The optimum process operating parameters were: temperature: 95°C; H O concentration: 0.5 M; sulfuric acid concentration: 2.5 M; time: 2 h; particle size: 74 μm, liquid-to-solid ratio: 14 ∶ 1 and agitation speed: 600 rpm. Under these experimental conditions, the extraction efficiency of molybdenum was about 98.4%, and the uranium extraction efficiency was about 98.7%. The leaching kinetics of molybdenum showed that the reaction rate of the leaching process is controlled by the chemical reaction at the particle surface. The leaching process follows the kinetic model 1 ? (1? ) = with an apparent activation energy of 40.40 kJ/mole. The temperature, concentrations of H O and H SO and the mesh size are the main factors that influence the leaching rate. The reaction order in H SO was 1.0012 and in H O it was 1.2544.

关键词： leaching of molybdenum     leaching of uranium     kinetics    

HTML PDF 收藏
分享

SUSTAINABLE DEVELOPMENT OF CROP-LIVESTOCK FARMS IN AFRICA

ONYANGO, Ousmane M. SANOGO, Ibrahim WANYAMA, Gabriel YESUF, David E. PELSTER

《农业科学与工程前沿（英文）》 2021年 第8卷 第1期   页码 175-181 doi: 10.15302/J-FASE-2020362

摘要： Crop-livestock farms across Africa are highly variable due to in agroecological and socioeconomic factors, the latter shaping the demand and supply of livestock products. Crop-livestock farms in Africa in the 21st century are very different from most mixed farms elsewhere in the world. African crop-livestock farms are smaller in size, have fewer livestock, lower productivity and less dependency on imported feed than farms in most countries of Europe, the Americas and the intensive agricultural systems of Asia. This paper discusses the role African crop-livestock farms have in the broader socio-agricultural economy, and how these are likely to change adapting to pressures brought on by the intensification of food systems. This intensification implies increasing land productivity (more food per hectare), often leading to more livestock heads per farm, producing fertilized feeds in croplands and importing feed supplements from the market. This discussion includes (1) the links between crop yields, soil fertility and crop-livestock integration, (2) the increasing demand for livestock products and the land resources required to meet to this demand, and (3) the opportunities to integrate broader societal goals into the development of crop-livestock farms. There is ample room for development of crop-livestock farms in Africa, and keeping integration as part of the development will help prevent many of the mistakes and environmental problems related to the intensification of livestock production observed elsewhere in the world. This development can integrate biodiversity, climate change adaptation and mitigation to the current goals of increasing productivity and food security. The inclusion of broader goals could help farmers access the level of finance required to implement changes.
HTML PDF 收藏
分享

Integrating space and time: a case for phenological context in grazing studies and management

Dawn M. BROWNING, Sheri SPIEGAL, Richard E. ESTELL, Andres F. CIBILS, Raul H. PEINETTI

《农业科学与工程前沿（英文）》 2018年 第5卷 第1期   页码 44-56 doi: 10.15302/J-FASE-2017193

摘要： In water-limited landscapes, patterns in primary production are highly variable across space and time. Livestock grazing is a common agricultural practice worldwide and a concern is localized overuse of specific pasture resources that can exacerbate grass losses and soil erosion. On a research ranch in New Mexico with average annual rainfall of 217 mm, we demonstrate with a quantitative approach that annual seasons vary greatly and examine foraging patterns in Angus-Hereford ( ) cows. We define five seasonal stages based on MODIS NDVI: pre-greenup, greenup, peak green, drydown and dormant, and examine livestock movements in 2008. Daily distance traveled by cows was greater and foraging area expanded during periods with higher precipitation. A regression model including minimum NDVI, rainfall and their interaction explained 81% of the seasonal variation in distance traveled by cows ( <0.01). Cows explored about 81 ha·d while foraging, but tended to explore smaller areas as the pasture became greener (greenup and peak green stages). Cows foraged an average of 9.7 h daily and spent more time foraging with more concentrated search patterns as pastures became greener. Our findings suggest that phenological context can expand the capacity to compare and integrate findings, and facilitate meta-analyses of grazing studies conducted at different locations and times of year.

关键词： GPS collars     Jornada Experimental Range     land-surface phenology     livestock movement     LTAR     MODIS NDVI     rangeland    

HTML PDF 收藏
分享

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

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    

HTML PDF 收藏
分享

Experimental evaluation and simulation of volumetric shrinkage and warpage on polymeric composite short natural fibers reinforced injection molded

GARCÍA,Luis E. GARZÓN,Luis M. LÓPEZ

《机械工程前沿（英文）》 2015年 第10卷 第3期   页码 287-293 doi: 10.1007/s11465-015-0346-x

摘要：

A polymeric natural fiber-reinforced composite is developed by extrusion and injection molding process. The shrinkage and warpage of high-density polyethylene reinforced with short natural fibers of Guadua angustifolia Kunth are analyzed by experimental measurements and computer simulations. Autodesk Moldflow® and Solid Works® are employed to simulate both volumetric shrinkage and warpage of injected parts at different configurations: 0 wt.%, 20 wt.%, 30 wt.% and 40 wt.% reinforcing on shrinkage and warpage behavior of polymer composite. Become evident the restrictive effect of reinforcing on the volumetric shrinkage and warpage of injected parts. The results indicate that volumetric shrinkage of natural composite is reduced up to 58% with fiber increasing, whereas the warpage shows a reduction form 79% to 86% with major fiber content. These results suggest that it is a highly beneficial use of natural fibers to improve the assembly properties of polymeric natural fiber-reinforced composites.

关键词： biocomposite     natural fiber     shrinkage     simulation     warpage    

HTML PDF 收藏
分享

Highly active and durable Pd-Cu catalysts for oxygen reduction in alkaline exchange membrane fuel cells

OMASTA, Justin M. ROLLER, William E. MUSTAIN

《能源前沿（英文）》 2017年 第11卷 第3期   页码 299-309 doi: 10.1007/s11708-017-0495-1

摘要： A Pd-Cu catalyst, with primary B2-type phase, supported by VulcanXC-7R carbon was synthesized via a solvothermal method. The catalysts were physically and electrochemically characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and both cyclic and linear sweep voltammetry using a rotating disk electrode (RDE). During the RDE testing, the half-wave potential of the Pd-Cu/Vulcan catalyst was 50 mV higher compared to that of commercial Pt/C catalyst for the oxygen reduction reaction (ORR) in alkaline media. The Pd-Cu/Vulcan exhibited a specific activity of 1.27 mA/cm and a mass activity of 0.59 A/mg at 0.9 V, which were 4 and 3 times greater than that of the commercial Pt/C catalyst, respectively. The Pd-Cu/Vulcan catalyst also showed higher alkaline exchange membrane fuel cell (AEMFC) performance, with operating power densities of 1100 MW/cm operating on H /O and 700 MW/cm operating on H /Air (CO -free), which were markedly higher than those of the commercial Pt/C. The Pd-Cu/Vulcan catalyst also exhibited high stability during a short-term, AEMFC durability test, with only around 11% performance loss after 30 hours of operation, an improvement over most AEMFCs reported in the literature to date.

关键词： alkaline exchange membrane (AEM)     fuel cell     Pd-Cu     oxygen reduction     high performance     water    

HTML PDF 收藏
分享

快速球磨法高效实现各向同性气雾化MnAl 粉的纳米化制备 Article

Rial, E.M. Palmero, A. Bollero

《工程（英文）》 2020年 第6卷 第2期   页码 172-176 doi: 10.1016/j.eng.2019.03.013

摘要： 球磨（30 s）和退火后获得的矫顽力高达4.2 kOe (1 Oe = 79.6 A·m–1)，与早期文献报道的球磨时间超过20 h时的矫顽力相当。

关键词： 永磁体     纳米结构     相变     MnAl     气雾化     球磨法    

HTML PDF 收藏
分享

Effects of ambient temperature on regulated gaseous and particulate emissions from gasoline-, E10- andM15-fueled vehicles

Rencheng Zhu, Jingnan Hu, Liqiang He, Lei Zu, Xiaofeng Bao, Yitu Lai, Sheng Su

《环境科学与工程前沿（英文）》 2021年 第15卷 第1期 doi: 10.1007/s11783-020-1306-1

摘要： Abstract • Emissions from two sedans were tested with gasoline, E10 and M15 at 30°C and -7°C. • As the temperature decreased, the PM, PN and BC emissions increased with all fuels. • Particulate emissions with E10 and M15 were more sensitive to the temperature. • The PN and BC generated during cold start-up dominated those over the WLTC. Ambient temperature has substantial impacts on vehicle emissions, but the impacts may differ between traditional and alcohol gasolines. The objective of this study was to investigate the effects of temperature on gaseous and particulate emissions with both traditional and alcohol gasoline. Regulated gaseous, particle mass (PM), particle number (PN) and black carbon (BC) emissions from typical passenger vehicles were separately quantified with gasoline, E10 (10% ethanol and 90% gasoline by volume) and M15 (15% methanol and 85% gasoline by volume) at both 30°C and -7°C. The particulate emissions with all fuels increased significantly with decreased temperature. The PM emissions with E10 were only 48.0%–50.7% of those with gasoline at 30°C but increased to 59.2%-79.4% at -7°C. The PM emissions with M15 were comparable to those with gasoline at 30°C, but at -7°C, the average PM emissions were higher than those with gasoline. The variation trend of PN emissions was similar to that of PM emissions with changes in the fuel and temperature. At 30°C, the BC emissions were lower with E10 and M15 than with gasoline in most cases, but E10 and M15 might emit more BC than gasoline at -7°C, especially M15. The results of the transient PN and BC emission rates show that particulate emissions were dominated mainly by those emitted during the cold-start moment. Overall, the particulate emissions with E10 and M15 were more easily affected by ambient temperature, and the advantages of E10 and M15 in controlling particulate emissions declined as the ambient temperature decreased.

关键词： Particle mass     Particle number     Black carbon     Alcohol gasoline     Low temperature    

HTML PDF 收藏
分享

一种高效的异构车辆集群协同框架 Research Articles

Iftikhar AHMAD1,2,Rafidah Md NOOR2,Zaheed AHMED3,Umm-e-HABIBA3,Naveed AKRAM4, 5,Fausto Pedro GARCÍA MÁRQUEZ6

《信息与电子工程前沿（英文）》 2021年 第22卷 第9期   页码 1247-1259 doi: 10.1631/FITEE.2000260

摘要： 异构车辆集群集成了多种类型通信网络，可在各种车辆应用中高效运行。长期演进（LTE）和专用短程通信的集成是异构网络的一种普遍形式。这种网络基础设施的异构性和成本/数据共享的不合作性是需要解决的潜在问题。车辆集群框架是解决这些问题的一种方案，但是该框架在部署到现实世界前应经过形式验证。为解决这些问题，提出一种异构的车辆集群框架，称为目标和兴趣感知集群框架。该框架集成了车载自组织网络与LTE网络，以提高道路交通效率。在此基础上，给出该框架的模型系统。使用模型检测技术对该模型进行形式验证，在功能层面评估其性能。为在微观层面评估该框架性能，通过整合最先进的工具创建异构仿真环境。仿真结果表明，与其他方法相比，该框架具有更好性能。

关键词： 车辆集群；异构性；协同；形式验证；系统模型    

HTML PDF 收藏
分享

标题 作者 时间 类型 操作

针对Wimax中多用户的考虑状态转移损失的省电算法

Bo LI,Sung-kwon PARK

期刊论文

基于最小速率保证的IEEE 802-16e公平调度算法

史俊财,胡爱群,关艳峰

期刊论文

基于多跳双向认证的802.16Mesh网络SA管理机制

王兴建,胡爱群,黄玉划

期刊论文

包容性工程——借助工程技术发明为身体或精神障碍人士赋能

Cummings, Philippe M. Fauchet, Michael Goldfarb, Martha W.M. Jones, Maithilee Kunda, Jonathan B.Stassun, Zachary E. Warren, Karl E. Zelik

期刊论文

Performance, emission and combustion characteristics of CI engine fuelled with diesel and hydrogen

Senthil KUMAR,M. LOGANATHAN,E. James GUNASEKARAN

期刊论文

使用IEEE 2030.5 标准在电网边缘进行可交易需求响应操作

Javad Fattahi, Mikhak Samadi, Melike Erol-Kantarci, Henry Schriemer

期刊论文

Oxidative leaching kinetics of molybdenum-uranium ore in H

Lasheen, M. E. El-Ahmady, H. B. Hassib, A. S. Helal

期刊论文

SUSTAINABLE DEVELOPMENT OF CROP-LIVESTOCK FARMS IN AFRICA

ONYANGO, Ousmane M. SANOGO, Ibrahim WANYAMA, Gabriel YESUF, David E. PELSTER

期刊论文

Integrating space and time: a case for phenological context in grazing studies and management

Dawn M. BROWNING, Sheri SPIEGAL, Richard E. ESTELL, Andres F. CIBILS, Raul H. PEINETTI

期刊论文

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

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

期刊论文

Experimental evaluation and simulation of volumetric shrinkage and warpage on polymeric composite short natural fibers reinforced injection molded

GARCÍA,Luis E. GARZÓN,Luis M. LÓPEZ

期刊论文

Highly active and durable Pd-Cu catalysts for oxygen reduction in alkaline exchange membrane fuel cells

OMASTA, Justin M. ROLLER, William E. MUSTAIN

期刊论文

快速球磨法高效实现各向同性气雾化MnAl 粉的纳米化制备

Rial, E.M. Palmero, A. Bollero

期刊论文

Effects of ambient temperature on regulated gaseous and particulate emissions from gasoline-, E10- andM15-fueled vehicles

Rencheng Zhu, Jingnan Hu, Liqiang He, Lei Zu, Xiaofeng Bao, Yitu Lai, Sheng Su

期刊论文

一种高效的异构车辆集群协同框架

Iftikhar AHMAD1,2,Rafidah Md NOOR2,Zaheed AHMED3,Umm-e-HABIBA3,Naveed AKRAM4, 5,Fausto Pedro GARCÍA MÁRQUEZ6

期刊论文