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Aslotted floor acquisitionmultiple access based MACprotocol for underwater acoustic networks withRTS

Liang-fang QIAN,Sen-lin ZHANG,Mei-qin LIU

《信息与电子工程前沿(英文)》 2015年 第16卷 第3期   页码 217-226 doi: 10.1631/FITEE.1400187

摘要: Long propagation delay, limited bandwidth, and high bit error rate pose great challenges in media access control (MAC) protocol design for underwater acoustic networks. A MAC protocol called slotted floor acquisition multiple access (slotted-FAMA) suitable for underwater acoustic networks is proposed and analyzed. This FAMA based protocol adds a time slot mechanism to avoid DATA packet collisions. However, slotted-FAMA is not suitable for dense networks since the multiple request-to-send (RTS) attempts problem in dense networks is serious and greatly limits the network throughput. To overcome this drawback, this paper proposes a slotted-FAMA based MAC protocol for underwater acoustic networks, called RC-SFAMA. RC-SFAMA introduces an RTS competition mechanism to keep the network from high frequency of backoff caused by the multiple RTS attempts problem. Via the RTS competition mechanism, useful data transmission can be completed successfully when the situation of multiple RTS attempts occurs. Simulation results show that RC-SFAMA increases the network throughput efficiency as compared with slotted-FAMA, and minimizes the energy consumption.

关键词: Underwater acoustic networks     Medium access control (MAC)     Request-to-send (RTS) competition     Throughput     Energy consumption    

Deep eutectic ionic liquids based on DABCO-derived quaternary ammonium salts: A promising reaction mediumin gaining access to terpyridines

Muhammad Faisal, Azeem Haider, Quret ul Aein, Aamer Saeed, Fayaz Ali Larik

《化学科学与工程前沿(英文)》 2019年 第13卷 第3期   页码 586-598 doi: 10.1007/s11705-018-1788-6

摘要: Owing to the directional H-bonding, coordination and -stacking abilities, terpyridines have been widely used as supramolecular tectons in molecular architectures, skeletons in molecular devices and metallopolymers, and are gaining importance in medicinal chemistry. In this paper, we have synthesized, characterized and applied deep eutectic ionic liquids (DEILs) based on 1,4-diazabicyclo[2.2.2]octane; triethylenediamine (DABCO)-derived quaternary ammonium salts for the preparation of terpyridines. These DEILs were synthesized through -alkylation of DABCO with haloalkanes (1-bromopentane or 1-bromoheptane) followed by mixing and heating with methanol or polyethylene glycol as a hydrogen bond donor. The synthesized DEILs were structurally characterized by IR and NMR. The formation of deep eutectic solvent was confirmed by freezing point depression, it composition was investigated through phase diagram, and its thermal stability was determined through differential scanning calorimetry, derivative thermogravimetry and thermal gravimetric analysis studies. Further, theseDEILswereinvestigatedfor theireffectivenesstowards synthesis of 2,2′:6′,2″-terpyridine, 3,2′:6′,3″-terpyridineand 4,2′:6′,4″-terpyridinederivatives through Kröhnke reaction. The results show that these three types of terpyridines can be obtained in reasonable yields (80% 97%) by the one-pot reaction of 2-, 3- or 4-acetylpyridine with a variety of aromatic aldehydes in the presence of DEIL as a reaction medium, sodium hydroxide as a base and ammonium acetate as a cyclizing agent. This methodology is highly efficient and cost-effective for synthesis of symmetrical as well as unsymmetrical terpyridines. Importantly, these DEILs can be reused several times without an obvious loss of activity and are non-toxic, low-volatile, biodegradable and highly thermally stable. Therefore, these DEILs as a non-conventional reaction medium for the synthesis of terpyridines provides appealing opportunities to be investigated in the domain of green synthesis.

关键词: terpyridine     deep eutectic solvent     ionic liquid     Kröhnke reaction     DABCO    

基于Web服务的分布式仿真系统的双重访问控制

陈学勤,吴慧中,朱耀琴

《中国工程科学》 2009年 第11卷 第8期   页码 72-78

摘要:

随着分布式仿真系统与Web服务技术的结合日益紧密,以及功能与资源分离的愈加明显,导致大量仿真资源暴露于网络中,传统、单一的访问控制模型已无法应对。为此提出了一种基于属性的针对功能和资源的双重访问控制模型,采用证书代理机制实现功能端单点登录,采用XACML实现资源端多属性的访问控制。详细描述了该模型的访问控制流程,目前已应用到虚拟采办系统中。通过对性能的分析和测试,证明了该双重访问控制模型的可用性和有效性。

关键词: Web服务安全     双重访问控制     分布式仿真系统    

Control division of agricultural non-point source pollution at medium-sized watershed scale in Southeast

HUANG Jinliang, HONG Huasheng, ZHANG Luoping

《环境科学与工程前沿(英文)》 2008年 第2卷 第3期   页码 333-339 doi: 10.1007/s11783-008-0035-7

摘要: This paper presents the study carried out for controlling agricultural non-point source pollution (NSP) in a medium-sized watershed covering 1.47 × 10 km in Southeast China using quantitative analysis coupled with geographic information system (GIS), universal soil loss equation (USLE), soil conservation service-curve number (SCS-CN), nutrient loss equations, and annualized agricultural nonpoint source model (AnnAGNPS). Based on the quantitative results derived from GIS and environmental models, five control division units were generated for NSP control in Jiulong River watershed, namely, controlling unit for soil losses, controlling unit for livestock breeding and soil losses, controlling unit for excessive fertilizer use and livestock breeding, controlling unit for soil losses and fertilizer use, and controlling unit for excessive fertilizer use and soil losses. This study proved that integrating GIS with environmental models can be adopted to efficiently evaluate major sources and contributors of NSP, and identify the critical source areas of NSP, which enables adjusting measures to local conditions by further control division units developed through such study for control and management of water quality degradation induced by NSP in the Jiulong River watershed.

基于双重分组和密钥计数的并行认证模式

黄玉划,胡爱群,宋宇波

《中国工程科学》 2004年 第6卷 第7期   页码 70-74

摘要:

由于CBC-MAC模式不可并行处理,提出了一种基于双重分组的并行认证模式(PKCB)。在此基础上提出了一种基于密钥计数的并行认证模式(KCTR-MAC)。KCTR-MAC模式安全性比PMAC模式高得多,而速率未降低,KCTR-MAC认证模式和CTR加密模式结合也可构成分组密码算法的一种全工作模式(2CTR),2CTR模式的综合性能不亚于标准模式CCM(CTRwith CBC-MAC),是一种安全快速的实用模式。

关键词: 认证模式     CBC-MAC模式     PMAC模式     CTR模式     CCM模式    

流域水土环境污染跨介质治理策略

夏星辉 ,裴元生 ,郑少奎 ,刘瑞民 ,文武 ,王功芹 ,杨志峰

《中国工程科学》 2022年 第24卷 第5期   页码 49-55 doi: 10.15302/J-SSCAE-2022.05.007

摘要:

污染物在流域水土环境中存在复杂的源汇关系,在水土环境中的转化作用主要受控于各种水‒ 土界面过程,为此,水土环境污染治理需将水土环境作为一个整体,通过跨介质归因识别找到真正的污染源,然后进行跨介质治理。本文首先分析了污染物在流域水土环境中的跨水‒ 土介质迁移过程以及主要影响因素,在此基础上提出了流域水土环境跨介质调控原理及关键过程,主要包括流域水土环境污染跨介质归因识别和流域水土环境污染跨介质治理。同时,重点阐述了污染物在河道外的土壤‒ 水界面、坡面‒ 河道界面,河道内的水‒ 沉积物界面(包括河床潜流带和侧向岸边潜流带的水‒固界面)和水‒ 悬浮颗粒物界面过程在跨介质去除中的重要作用,并采用实际案例阐述了流域非点源污染物的跨介质控制、河流含氮化合物的跨介质去除以及湖泊氮磷的跨介质去除方法等。研究结果可为流域水土环境污染防治提供科学依据。

关键词: 流域;水土污染防治;水土环境;水 ‒ 沉积物界面;水环境质量;跨介质治理    

大中功率节能调速传动的合理电压等级

马小亮

《中国工程科学》 2001年 第3卷 第11期   页码 80-84

摘要:

大中功率风机和泵采用变频调速可节约大量电能,大部分功率在0.2~2 MW范围中。我国现在200 kW以上的电机多是中压,现行中压电网多为10 kV,选用10 kV直接变频从技术和经济角度看都不太合理。由于变频器输入侧都有变压器,因此电机和变频器没有必要和电网一致。文章讨论不同功率段的合理电压等级以及在电机电压和电网电压不同情况下当变频器出现故障时如何实现旁路工作。

关键词: 大中功率     节能调速     合理电压等级     低压变频     中压变频     旁路    

Uncoupled state space solution to layered poroelastic medium with anisotropic permeability and compressible

Zhiyong AI, Wenze ZENG, Yichong CHENG, Chao WU

《结构与土木工程前沿(英文)》 2011年 第5卷 第2期   页码 171-179 doi: 10.1007/s11709-011-0103-0

摘要: This paper presents an uncoupled state space solution to three-dimensional consolidation of layered poroelastic medium with anisotropic permeability and compressible pore fluid. Starting from the basic equations of poroelastic medium, and introducing intermediate variables, the state space equation usually comprising eight coupled state vectors is uncoupled into two sets of equations of six and two state vectors in the Laplace-Fourier transform domain. Combined with the continuity conditions between adjacent layers and boundary conditions, the uncoupled state space solution of a layered poroelastic medium is obtained by using the transfer matrix method. Numerical results show that the anisotropy of permeability and the compressibility of pore fluid have remarkable influence on the consolidation behavior of poroelastic medium.

关键词: uncoupled state space solution     layered poroelastic medium     three-dimensional consolidation     anisotropic permeability     compressible pore fluid    

Preparation of solar selective absorbing CuO coating for medium temperature application

HUANG Qunwu, WANG Yiping, LI Jinhua

《化学科学与工程前沿(英文)》 2007年 第1卷 第3期   页码 256-260 doi: 10.1007/s11705-007-0046-0

摘要: A new method of preparing CuO solar selective absorbing coating for medium temperature is presented. After pretreatment, brass was overlaid with CuO by chemical plating. The effects of reactant concentration, reaction temperature and reaction time on the absorptivity of CuO coating were investigated. The optimized condition of preparing CuO coating was obtained. The CuO coating was analyzed with X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). In order to prolong the period of use, the CuO coating was protected by TiO. The experiment shows that the TiO/CuO coating is more heat-resistant, acid-resistant, and wear resistant than CuO coating, without losing absorptivity markedly. The TiO coating can reduce emissivity and protect the CuO coating.

关键词: photoelectron spectroscopy     temperature     pretreatment     absorptivity     microscopy    

Frontier of continuous structural health monitoring system for short & medium span bridges and condition

Ayaho MIYAMOTO, Risto KIVILUOMA, Akito YABE

《结构与土木工程前沿(英文)》 2019年 第13卷 第3期   页码 569-604 doi: 10.1007/s11709-018-0498-y

摘要: It is becoming an important social problem to make maintenance and rehabilitation of existing short and medium span(10-20 m) bridges because there are a huge amount of short and medium span bridges in service in the world. The kernel of such bridge management is to develop a method of safety(condition) assessment on items which include remaining life and load carrying capacity. Bridge health monitoring using information technology and sensors is capable of providing more accurate knowledge of bridge performance than traditional strategies. The aim of this paper is to introduce a state-of-the-art on not only a rational bridge health monitoring system incorporating with the information and communication technologies for lifetime management of existing short and medium span bridges but also a continuous data collecting system designed for bridge health monitoring of mainly short and medium span bridges. In this paper, although there are some useful monitoring methods for short and medium span bridges based on the qualitative or quantitative information, mainly two advanced structural health monitoring systems are described to review and analyse the potential of utilizing the long term health monitoring in safety assessment and management issues for short and medium span bridge. The first is a special designed mobile loading device(vehicle) for short and medium span road bridges to assess the structural safety(performance) and derive optimal strategies for maintenance using reliability based method. The second is a long term health monitoring method by using the public buses as part of a public transit system (called bus monitoring system) to be applied mainly to short and medium span bridges, along with safety indices, namely, “characteristic deflection” which is relatively free from the influence of dynamic disturbances due to such factors as the roughness of the road surface, and a structural anomaly parameter.

关键词: condition assessment     short & medium span bridge     structural health monitoring(SHM)     long-term data collection     system     maintenance     bridge performance     information technology     loading vehicle(public bus)     in-situ loading    

“数控一代”示范工程引领和推动共性使能技术在中小企业推广应用

魏峰,周源,薛澜

《中国工程科学》 2017年 第19卷 第3期   页码 45-52 doi: 10.15302/J-SSCAE-2017.03.007

摘要:

数控技术是推动机械产品升级换代的关键共性使能技术。考虑到广大中小企业自身技术、资金等诸多障碍和市场失灵、组织失灵问题,共性使能技术在推广应用中存在严重的“死亡之谷”现象。“数控一代”示范工程的工作方针是以需求为牵引、以创新为动力、以企业为主体、“用产学研金政”紧密结合、重点突破、成功示范。“数控一代”示范工程将数控技术应用到典型行业的机械产品中,使装备和产品性能得到本质提升,加快机械产品整体升级换代和企业向可持续发展转型升级的步伐,在共性使能技术研发与企业创新生产之间的鸿沟上架起一座桥梁,取得了显著的成就,是共性使能技术推广应用的成功范例,为进一步在各个行业、区域全面普及数控技术及开展“智能一代”机械产品创新应用工程提供有益借鉴并奠定坚实的基础。

关键词: 示范工程     共性使能技术     技术创新扩散     中小企业     转型升级    

大中型水利工程建设管理的实践和体会

张基尧

《中国工程科学》 2011年 第13卷 第8期   页码 22-25

摘要: 水利工程建设是基础设施建设的重要组成部分。加强水利工程建设管理是提高水利投资效益和社会、经济、生态效益的重要途经,是工程管理科学研究的重要内容。文章主要阐述了不同阶段大中型水利工程建设管理的责任主体、管理重点、有效做法和成功案例。

关键词: 大中型水利工程;项目管理;实践体会    

信息中心物联网节点状态监测技术研究

崔立群,伍军

《中国工程科学》 2020年 第22卷 第6期   页码 121-127 doi: 10.15302/J-SSCAE-2020.06.016

摘要:

为了管理信息中心物联网(IC-IoT)不断变化的网络状态信息,本文针对信息中心物联网提出一种节点状态监测方案,以更好适应未来网络的发展。首先提出一种新的管理信息库结构用于记录各种网络节点状态信息,采用信息中心网络(ICN)的命名格式,以网络节点状态内容本身为中心。在此架构上采用跟踪路由方法,结合基于数据块重要性的自适应数据放置策略来获得所需的网络状态信息,提高网络节点状态信息检索效率,同时设计了安全防护机制来达到保证数据机密性与对管理用户进行访问控制的目的。搭建网络仿真测试环境评估了上述跟踪路由机制、自适应数据放置策略、访问控制安全防护带来的时延影响,仿真结果表明此方案能够有效地提高数据获取效率,访问控制模型提供了数据机密性和其他安全性功能,仅附加了少量的计算成本。

关键词: 信息中心网络,物联网,节点监测,访问控制    

人体胃肠道–菌群相互作用的工程学研究模型

Marc Mac Giolla Eain, Joanna Baginska, Kacy Greenhalgh, Joëlle V.

《工程(英文)》 2017年 第3卷 第1期   页码 60-65 doi: 10.1016/J.ENG.2017.01.011

摘要:

研究宿主–胃肠道微生物的相互作用已经成为管理人类健康和疾病的关键组成部分。微生理系统的发展正在为研究人员提供前所未有的对于这种复杂关系的获取和理解。这些系统结合了微型工程、微流体和细胞培养的优点,来创建人类肠道中普遍存在的环境条件。在这里我们提出的HuMiX(人类微生物交联对话) 平台,是一个利用这种多学科方法提供具有代表性的人体胃肠道的体外模型系统,用于研究宿主–微生物分子的相互作用。我们总结了使用该平台获得的概念验证结果,强调其对于大大增强我们对宿主–微生物相互作用了解的潜力,且其可能对药物、食品和营养以及医疗保健行业产生的巨大影响。同时讨论了这些技术面临的一些关键问题和挑战。

关键词: 微生物     微流体     肠道芯片     HuMiX    

Easy access to pharmaceutically relevant heterocycles by catalytic reactions involving

Ximei Zhao, Matthias Rudolph, Abdullah M. Asiri, A. Stephen K. Hashmi

《化学科学与工程前沿(英文)》 2020年 第14卷 第3期   页码 317-349 doi: 10.1007/s11705-019-1874-4

摘要: This review summarizes recent advances in the field of gold-catalyzed synthesis of pharmaceutically relevant aza-heterocycles via generated -imino gold carbene complexes as intermediates.

关键词: gold     heterocycles     alkynes    

标题 作者 时间 类型 操作

Aslotted floor acquisitionmultiple access based MACprotocol for underwater acoustic networks withRTS

Liang-fang QIAN,Sen-lin ZHANG,Mei-qin LIU

期刊论文

Deep eutectic ionic liquids based on DABCO-derived quaternary ammonium salts: A promising reaction mediumin gaining access to terpyridines

Muhammad Faisal, Azeem Haider, Quret ul Aein, Aamer Saeed, Fayaz Ali Larik

期刊论文

基于Web服务的分布式仿真系统的双重访问控制

陈学勤,吴慧中,朱耀琴

期刊论文

Control division of agricultural non-point source pollution at medium-sized watershed scale in Southeast

HUANG Jinliang, HONG Huasheng, ZHANG Luoping

期刊论文

基于双重分组和密钥计数的并行认证模式

黄玉划,胡爱群,宋宇波

期刊论文

流域水土环境污染跨介质治理策略

夏星辉 ,裴元生 ,郑少奎 ,刘瑞民 ,文武 ,王功芹 ,杨志峰

期刊论文

大中功率节能调速传动的合理电压等级

马小亮

期刊论文

Uncoupled state space solution to layered poroelastic medium with anisotropic permeability and compressible

Zhiyong AI, Wenze ZENG, Yichong CHENG, Chao WU

期刊论文

Preparation of solar selective absorbing CuO coating for medium temperature application

HUANG Qunwu, WANG Yiping, LI Jinhua

期刊论文

Frontier of continuous structural health monitoring system for short & medium span bridges and condition

Ayaho MIYAMOTO, Risto KIVILUOMA, Akito YABE

期刊论文

“数控一代”示范工程引领和推动共性使能技术在中小企业推广应用

魏峰,周源,薛澜

期刊论文

大中型水利工程建设管理的实践和体会

张基尧

期刊论文

信息中心物联网节点状态监测技术研究

崔立群,伍军

期刊论文

人体胃肠道–菌群相互作用的工程学研究模型

Marc Mac Giolla Eain, Joanna Baginska, Kacy Greenhalgh, Joëlle V.

期刊论文

Easy access to pharmaceutically relevant heterocycles by catalytic reactions involving

Ximei Zhao, Matthias Rudolph, Abdullah M. Asiri, A. Stephen K. Hashmi

期刊论文