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造山带的网结状构造样式 被引量:11
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作者 索书田 《地质科技情报》 CAS CSCD 北大核心 1993年第2期1-7,共7页
网结状构造样式是造山带地壳结构的一个重要特征,表现为线状强应变带与夹持其间的透镜状弱应变域规律组合格式。这种网结状型式在几何学上具有尺度不变性,并具三维特征,理论分析和实际观察指出,这种网结状构造样式,是在应变软化作用及... 网结状构造样式是造山带地壳结构的一个重要特征,表现为线状强应变带与夹持其间的透镜状弱应变域规律组合格式。这种网结状型式在几何学上具有尺度不变性,并具三维特征,理论分析和实际观察指出,这种网结状构造样式,是在应变软化作用及变形分解作用控制下递进发育而成的,而造山带地壳结构的不均一性、组成造山带岩石的流变学特征以及变形物理环境,又是控制应变软化及变形分解作用的主要因素。 展开更多
关键词 秦岭 地体 网结状型式 造山带
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赣东北地区“网结状”韧性变形带阵列构造的特征及其构造意义浅析 被引量:9
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作者 崔学军 《江西地质》 1998年第3期213-217,共5页
本文从岩石学、几何学、运动学、矿物学等不同方面描述了赣东北地区“网结状”韧性变形带阵列构造的基本特征,并对其形成时代和构造意义进行了探讨,认为它是印支初期怀玉地体与九岭—鄣公地体碰撞拼贴造山运动的产物。
关键词 网结状 韧性变形带 阵列构造 赣东北
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对中国西部造山带地质研究若干问题的思考 被引量:34
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作者 李荣社 徐学义 计文化 《地质通报》 CAS CSCD 北大核心 2008年第12期2020-2025,共6页
从大陆研究的视角,认为大陆造山带地质研究是广义上的陆缘地质研究,阐述了陆缘多岛弧盆构造系统及其演化过程,提出造山带内时代相近的一组蛇绿混杂岩带是"古陆缘多岛弧盆格局"的残留,"古陆缘多岛弧盆构造系统"的基... 从大陆研究的视角,认为大陆造山带地质研究是广义上的陆缘地质研究,阐述了陆缘多岛弧盆构造系统及其演化过程,提出造山带内时代相近的一组蛇绿混杂岩带是"古陆缘多岛弧盆格局"的残留,"古陆缘多岛弧盆构造系统"的基本残留形式在平面和剖面上都可能是"网结状"等认识。 展开更多
关键词 陆缘构造 蛇绿构造混杂带 网结状 多岛弧盆系统
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Application of extension neural network to safety status pattern recognition of coalmines 被引量:6
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作者 周玉 W.Pedrycz 钱旭 《Journal of Central South University》 SCIE EI CAS 2011年第3期633-641,共9页
In order to accurately and quickly identify the safety status pattern of coalmines,a new safety status pattern recognition method based on the extension neural network (ENN) was proposed,and the design of structure of... In order to accurately and quickly identify the safety status pattern of coalmines,a new safety status pattern recognition method based on the extension neural network (ENN) was proposed,and the design of structure of network,the rationale of recognition algorithm and the performance of proposed method were discussed in detail.The safety status pattern recognition problem of coalmines can be regard as a classification problem whose features are defined in a range,so using the ENN is most appropriate for this problem.The ENN-based recognition method can use a novel extension distance to measure the similarity between the object to be recognized and the class centers.To demonstrate the effectiveness of the proposed method,a real-world application on the geological safety status pattern recognition of coalmines was tested.Comparative experiments with existing method and other traditional ANN-based methods were conducted.The experimental results show that the proposed ENN-based recognition method can identify the safety status pattern of coalmines accurately with shorter learning time and simpler structure.The experimental results also confirm that the proposed method has a better performance in recognition accuracy,generalization ability and fault-tolerant ability,which are very useful in recognizing the safety status pattern in the process of coal production. 展开更多
关键词 safety status pattern recognition extension neural network coal mines
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Microstructures and properties of Cu/Ag(Invar) composites fabricated by powder metallurgy 被引量:1
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作者 Xin ZHANG Dan WU +3 位作者 Lei YANG Chang-dong SHI Yu-cheng WU Wen-ming TANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2017年第8期1759-1766,共8页
The Ag(Invar)composite powder prepared by ball milling was used to fabricate the Cu/Ag(Invar)composites.Microstructures and properties of the composites were studied after sintering and thermo-mechanical treatment.The... The Ag(Invar)composite powder prepared by ball milling was used to fabricate the Cu/Ag(Invar)composites.Microstructures and properties of the composites were studied after sintering and thermo-mechanical treatment.The results indicatethat during ball milling,micro-forging weld and work-hardening fracture result in that the average particle size of the Ag(Invar)powder increases rapidly at first,and then decreases sharply,finally tends to be constant.Compared with the Cu/Invar ones,thesinterability of the composites is greatly improved,resulting in that the pores in them are smaller in amount and size.After thethermo-mechanical treatment,the Cu/Ag(Invar)composites are nearly fully dense with the optimum phase composition and elementdistribution.More importantly,Cu and the Invar alloy in the composites distribute continuously in a three-dimensional(3D)networkstructure.Cu/Invar interface diffusion is effectively inhibited by the Ag barrier layer,leading to a great improvement of themechanical and thermal properties of the Cu/Ag(Invar)composites. 展开更多
关键词 Cu/Invar composite Ag barrier layer SINTERING thermo-mechanical treatment 3D network structure mechanical properties thermal properties
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Honeycomb-structured solid acid catalysts fabricated via the swelling-induced self-assembly of acidic poly(ionic liquid)s for highly efficient hydrolysis reactions 被引量:2
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作者 Bihua Chen Tong Ding +6 位作者 Xi Deng Xin Wang Dawei Zhang Sanguan Ma Yongya Zhang Bing Ni Guohua Gao 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2021年第2期297-309,共13页
The development of heterogeneous acid catalysts with higher activity than homogeneous acid catalysts is critical and still challenging.In this study,acidic poly(ionic liquid)s with swelling ability(SAPILs)were designe... The development of heterogeneous acid catalysts with higher activity than homogeneous acid catalysts is critical and still challenging.In this study,acidic poly(ionic liquid)s with swelling ability(SAPILs)were designed and synthesized via the free radical copolymerization of ionic liquid monomers,sodium p-styrenesulfonate,and crosslinkers,followed by acidification.The 31P nuclear magnetic resonance chemical shifts of adsorbed trimethylphosphine oxide indicated that the synthesized SAPILs presented moderate and single acid strength.The thermogravimetric analysis results in the temperature range of 300–345°C revealed that the synthesized SAPILs were more stable than the commercial resin Amberlite IR-120(H)(245°C).Cryogenic scanning electron microscopy testing demonstrated that SAPILs presented unique three-dimensional(3D)honeycomb structure in water,which was ascribed to the swelling-induced self-assembly of the molecules.Moreover,we used SAPILs with micron-sized honeycomb structure in water as catalysts for the hydrolysis of cyclohexyl acetate to cyclohexanol,and determined that their catalytic activity was much higher than that of homogeneous acid catalysts.The equilibrium concentrations of all reaction components inside and outside the synthesized SAPILs were quantitatively analyzed using a series of simulated reaction mixtures.Depending on the reaction mixture,the concentration of cyclohexyl acetate inside SAPIL-1 was 7.5–23.3 times higher than that outside of it,which suggested the high enrichment ability of SAPILs for cyclohexyl acetate.The excellent catalytic performance of SAPILs was attributed to their 3D honeycomb structure in water and high enrichment ability for cyclohexyl acetate,which opened up new avenues for designing highly efficient heterogeneous acid catalysts that could eventually replace conventional homogeneous acid catalysts. 展开更多
关键词 Heterogeneous acid catalyst Acidic poly(ionic liquid) SWELLING 3D honeycomb structure Enrichment Hydrolysis HYDRATION
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Intrusion Detection for Wireless Mesh Networks using Finite State Machine 被引量:5
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作者 Yi Ping Wu Yue +1 位作者 Liu Ning Wang Zhiyang 《China Communications》 SCIE CSCD 2010年第5期40-48,共9页
Wireless Mesh Networks is vulnerable to attacks due to the open medium, dynamically changing network topology, cooperative algorithms, Lack of centralized monitoring and management point. The traditional way of protec... Wireless Mesh Networks is vulnerable to attacks due to the open medium, dynamically changing network topology, cooperative algorithms, Lack of centralized monitoring and management point. The traditional way of protecting networks with firewalls and encryption software is no longer suffi- cient and effective for those features. In this paper, we propose a distributed intrusion detection ap- proach based on timed automata. A cluster-based detection scheme is presented, where periodically a node is elected as the monitor node for a cluster. These monitor nodes can not only make local intrusion detection decisions, but also cooperatively take part in global intrusion detection. And then we con- struct the Finite State Machine (FSM) by the way of manually abstracting the correct behaviors of the node according to the routing protocol of Dynamic Source Routing (DSR). The monitor nodes can verify every node's behavior by the Finite State Ma- chine (FSM), and validly detect real-time attacks without signatures of intrusion or trained data.Compared with the architecture where each node is its own IDS agent, our approach is much more efficient while maintaining the same level of effectiveness. Finally, we evaluate the intrusion detection method through simulation experiments. 展开更多
关键词 wireless mesh networks SECURITY intrusion detection finite state machine
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Continuous Weight Attack on Complex Network
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作者 YIN Yan-Ping ZHANG Duan-Ming +2 位作者 TAN Jin PAN Gui-Jun HE Min-Hua 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第3期797-800,共4页
We introduce a continuous weight attack strategy and numerically investigate the effect of continuous weight attack strategy on the Barabasi-Albert (BA) scale-free network and the Erdos-Rdnyi (ER) random network. ... We introduce a continuous weight attack strategy and numerically investigate the effect of continuous weight attack strategy on the Barabasi-Albert (BA) scale-free network and the Erdos-Rdnyi (ER) random network. We use a weight coefficient ω to define the attack intensity. The weight coefficient ω increases continuously from 1 to infinity, where 1 represents no attack and infinity represents complete destructive attack. Our results show that the continuous weight attack on two selected nodes with small ω (ω≈ 3) could achieve the same damage of complete elimination of a single selected node on both BA and ER networks. It is found that the continuous weight attack on a single selected edge with small ω (ω≈ 2) can reach the same effect of complete elimination of a single edge on BA network, but on ER network the damage of the continuous weight attack on a single edge is c/ose to but always smaller than that of complete elimination of edge even if ω is very large. 展开更多
关键词 network efficiency weight coefficient weak attack complex networks
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Wind-induced vibration of single-layer reticulated shell structures
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作者 张建胜 武岳 沈世钊 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2008年第4期494-498,共5页
Aiming at the dynamic response of reticulated shell structures under wind load,systematic parameter analyses on wind-induced responses of Kiewitt6-6 type single-layer spherical reticulated shell structures and three-w... Aiming at the dynamic response of reticulated shell structures under wind load,systematic parameter analyses on wind-induced responses of Kiewitt6-6 type single-layer spherical reticulated shell structures and three-way grid single-layer cylindrical reticulated shell structures were performed with the random simulation method in time domain,including geometric parameters,structural parameters and aerodynamic parameters.Moreover,a wind-induced vibration coefficient was obtained,which can be a reference to the wind-resistance design of reticulated shell structures.The results indicate that the geometric parameters are the most important factor influencing wind-induced responses of the reticulated shell structures;the wind-induced vibration coeffi-cient is 3.0-3.2 for the spherical reticulated shell structures and that is 2.8-3.0 for the cylindrical reticula-ted shell structures,which shows that the wind-induced vibration coefficients of these two kinds of space frames are well-proportioned. 展开更多
关键词 reticulated shell structures wind-induced response random simulation method in time domain wind-induced vibration coefficient
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Synthesis and 2D H-bonded Cd(Ⅱ) Network Structure of [Cd(C_(10)H_(15)N_3)Cl_2]
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作者 边贺东 徐靖源 +4 位作者 顾文 阎世平 廖代正 姜宗慧 程鹏 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2003年第6期710-712,共3页
The title complex [CdLCl2] 1 (C10H15CdCl2N3, Mr = 360.55) has been synthesized by the reaction of CdCl22.5H2O with the tridentate Schiff base L, N,N-dimethyl-N-pyridin-2-yl- methylene-1,2-diaminoethane, which is deriv... The title complex [CdLCl2] 1 (C10H15CdCl2N3, Mr = 360.55) has been synthesized by the reaction of CdCl22.5H2O with the tridentate Schiff base L, N,N-dimethyl-N-pyridin-2-yl- methylene-1,2-diaminoethane, which is derived from the condensation reaction of pyridine-2- carboxaldehyde and N,N-dimethylethylenediamine. It crystallizes in the monoclinic system, space group C2/c with a = 25.054(13), b = 7.532(4), c = 16.119(8) ? b = 116.238(8)? V = 2728(2) ?, Z = 8, Dc = 1.756 g/cm3, m(MoKa) = 1.970 mm-1, F(000) = 1424, R = 0.0297 and wR = 0.0625. Crystal analyses reveal that the cadmium atom is coordinated by two chlorine atoms and three N atoms from the tridentate ligand in a distorted tetragonal pyramidal environment. Each complex molecule is connected with four surrounding ones to form 2D network by hydrogen bonds along the bc plane. The chlorine atoms act as acceptors and the carbon atoms of the tridentate Schiff base as donors with the CH…Cl distances in the range of 3.518~3.752 ? 展开更多
关键词 crystal structures cadmium(Ⅱ) complex 2D network structure hydrogen bonds
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Sound absorption performance of various nickel foam-base multi-layer structures in range of low frequency 被引量:3
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作者 Wei CHENG Cui-yun DUAN +1 位作者 Pei-sheng LIU Miao LU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2017年第9期1989-1995,共7页
Commercial3D reticular nickel foam and its composite structure were investigated on the sound absorption at200-2000Hz.The absorption performance of foam plates1?5layers(1-layer thickness:2.3mm;porosity:89%;average por... Commercial3D reticular nickel foam and its composite structure were investigated on the sound absorption at200-2000Hz.The absorption performance of foam plates1?5layers(1-layer thickness:2.3mm;porosity:89%;average pore-diameter:0.57mm)was found to be poor,and could be improved by adding backed cavum or front perforated thin sheet.The absorption coefficient could reach about0.4at1000-1600Hz for the composite structure of5-layer foam with a backed5mm-thick cavum,and even0.68at about1000Hz for that of2-layer foam with the same cavum and a perforated plate closely in front of the foam. 展开更多
关键词 reticular metal foam reticular nickel foam composite structure for sound absorption low frequency sound absorption
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Establishment of antenna membrane states FEM on analogue method
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作者 姜文辉 曹喜滨 赵阳 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2008年第5期635-637,共3页
On the basis of choosing the basic element as the bar and choosing the basic mesh as the triangle as well as supposing the conditions of the element, the membrane states of an antenna reflector were researched by the ... On the basis of choosing the basic element as the bar and choosing the basic mesh as the triangle as well as supposing the conditions of the element, the membrane states of an antenna reflector were researched by the analogue method, because the membrane effect was not omitted during the ending deployment process of the radial rib antenna. The expressions of the bar element’s section area and density were obtained, while the expression of the stress state during the ending deployment process of antenna was attained. During the establishment process of the analogue method, the analysis method of the net shell structure was employed. Moreover, during the backward deduction of membrane stress, the continuation method was adopted. Because the expression of the membrane stress state can realize the analysis on the antenna membrane state, this research has great significance of theoretical direction to the normal operation of the space deployable antenna. 展开更多
关键词 radial rib antenna analogue method net shell structure continuation method membrane states
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High-strength Ti-BN composites with core-shell structured matrix and network-woven structured TiB nanowires
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作者 Li-qing HUANG Qun HUANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第4期1169-1177,共9页
A novel architectural Ti composite composed of network-woven structured TiB nanowires in a core-shell structured Ti matrix was fabricated to improve the strength of Ti matrix composites(TMCs),where the shell consists ... A novel architectural Ti composite composed of network-woven structured TiB nanowires in a core-shell structured Ti matrix was fabricated to improve the strength of Ti matrix composites(TMCs),where the shell consists of rich N solute atoms while the core is deficient of N solute atoms through spark plasma sintering of powder mixtures of Ti powder and BN nano-powder.The phase composition,morphology,element distribution,and mechanical properties of prepared samples were analyzed by X-ray diffraction(XRD),scanning electron microscope(SEM),electron probe microanalyzer(EPMA),and electronic universal material testing machine.The results indicate that the TMCs with designed architectures have been successfully achieved,and the as-prepared Ti-2BN(wt.%)composite exhibits an ultimate compressive strength of~1.8 GPa with a strain-to-fracture of~9%,while the Ti-1BN(wt.%)attains an ultimate compressive strength of~1.6 GPa and a strain-to-fracture of~20%.Moreover,the roles of the hybrid reinforcement structures in strengthening the Ti composites were discussed. 展开更多
关键词 titanium matrix composites TiB nanowires NITROGEN network-woven structure core-shell structure
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System Recovery-Aware Virus Propagation Model and Its Steady-State Analysis 被引量:1
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作者 Lin Sun Cai Fu +3 位作者 Ming Fu Deliang Xu Lansheng Han Deqing Zou 《China Communications》 SCIE CSCD 2016年第5期151-161,共11页
Network structures and human behaviors are considered as two important factors in virus defense currently. However, due to ignorance of network security, normal users usually take simple activities, such as reinstalli... Network structures and human behaviors are considered as two important factors in virus defense currently. However, due to ignorance of network security, normal users usually take simple activities, such as reinstalling computer system, or using the computer recovery system to clear virus. How system recovery influences virus spreading is not taken into consideration currently. In this paper, a new virus propagation model considering the system recovery is proposed first, and then in its steady-state analysis, the virus propagation steady time and steady states are deduced. Experiment results show that models considering system recovery can effectively restrain virus propagation. Furthermore, algorithm with system recovery in BA scale-free network is proposed. Simulation result turns out that target immunization strategy with system recovery works better than traditional ones in BA network. 展开更多
关键词 computer virus system recovery virus propagation model target immunization strategy
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Sound absorption of several various nickel foam multilayer structures at aural frequencies sensitive for human ears 被引量:1
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作者 Pei-sheng LIU Xin-bang XU +1 位作者 Wei CHENG Jing-he CHEN 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2018年第7期1334-1341,共8页
Using the three-dimensional reticular nickel foam as experimental material, the sound absorption performance was investigated for several various multilayer structures in the frequency range of 2000-4000 Hz, which is ... Using the three-dimensional reticular nickel foam as experimental material, the sound absorption performance was investigated for several various multilayer structures in the frequency range of 2000-4000 Hz, which is aurally sensitive for human ears. The results showed that the 7.5 mm-thick foam sample, which was formed by piling of 5-layer foam plate(thickness: 1.5 mm; porosity: 96%; average pore-diameter: 0.65 mm) could exhibit an excellent sound absorption effect at 4000 Hz, with the absorption coefficient about 0.8. Constituting alternate air gap with the total thickness of about 18.5 mm can greatly improve the absorption performance at relatively low frequencies of 2000-3150 Hz, with the absorption coefficient up to about 0.5 or more. In addition, the research showed that alternate piling up the perforated plate inside the foam plates can also achieve a quite good effect of sound absorption at relatively low frequencies. 展开更多
关键词 reticular nickel foam composite structure of sound absorption aurally sensitive frequency sound absorption
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Degradation efficiency of Mg_(65)Cu_(25-x)Ag_(x)Y_(10) nanoporous dealloyed ribbons on pesticide wastewater 被引量:1
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作者 Qing XIA Shi-yao HE +4 位作者 Wei ZHANG Qing-chun XIANG Ying-dong QU Ying-lei REN Ke-qiang QIU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第5期1472-1484,共13页
Dealloyed ribbons with a layer of networked nanoporous structure of different pore sizes were fabricated by dealloying the as-spun Mg_(65)Cu_(25-x)Ag_(x)Y_(10)(x=0,5,10,at.%)ribbons in dilute H_(2)SO_(4) solution in o... Dealloyed ribbons with a layer of networked nanoporous structure of different pore sizes were fabricated by dealloying the as-spun Mg_(65)Cu_(25-x)Ag_(x)Y_(10)(x=0,5,10,at.%)ribbons in dilute H_(2)SO_(4) solution in order to enhance the degradation efficiency of pesticide wastewater.Compared to the as-spun ribbons,it is found that the dealloyed ribbons with the networked nanoporous structure exhibit higher degradation efficiency due to their large specific surface areas and enough active sites for the degradation process.Both the average pore sizes of the nanoporous structure and the degradation efficiency of the pesticide wastewater increase with the increase of Ag addition in the dealloyed ribbons.The maximum degradation efficiency up to 95.8%is obtained for the Mg_(65)Cu_(15)Ag_(10)Y_(10)dealloyed ribbon under the optimal conditions of pH being 3,the initial cis-cypermethrin concentration being 500 mg/L,and the dosage of dealloyed ribbon being 1.33 g/L. 展开更多
关键词 networked nanoporous structure MgCu-based amorphous ribbon DEALLOYING cis-cypermethrin wastewater degradation efficiency
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DTMC-based Modeling and Analysis of Obstacle Ad hoc Networks
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作者 Tong Ning Wu Di Wang Xiukun 《China Communications》 SCIE CSCD 2010年第5期83-92,共10页
One of the main characteristics of Ad hoc networks is node mobility, which results in constantly changing in network topologies. Consequently, the ability to forecast the future status of mobility nodes plays a key ro... One of the main characteristics of Ad hoc networks is node mobility, which results in constantly changing in network topologies. Consequently, the ability to forecast the future status of mobility nodes plays a key role in QOS routing. We propose a random mobility model based on discretetime Markov chain, called ODM. ODM provides a mathematical framework for calculating some parameters to show the future status of mobility nodes, for instance, the state transition probability matrix of nodes, the probability that an edge is valid, the average number of valid-edges and the probability of a request packet found a valid route. Furthermore, ODM can account for obstacle environment. The state transition probability matrix of nodes can quantify the impact of obstacles. Several theorems are given and proved by using the ODM. Simulation results show that the calculated value can forecast the future status of mobility nodes. 展开更多
关键词 Ad hoc network discrete time markov chain mobility model OBSTACLE
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The First Three-dimensional Crown Ether Complex:{[Na(B18-C-6)]_(6)[Pt(SCN)_(6)]}[Pt(SCN)_(6)](SCN)_(2)with Covalent Bond
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作者 YIN Jin-biao SUN Feng-wen +1 位作者 LI Da-cheng DOU Jian-min 《聊城大学学报(自然科学版)》 2003年第2期11-13,共3页
The novel benzo-18-crown-6(B18-C-6)complex;{[Na(Bl8-C-6)]_(6)[Pt(SCN)_(6)]}[Pt(SCN)_(6)](SCN)_(2)(1)was synthesized and characterized by elemental analysis,IR spectrum and x-ray diffraction analysis.Thr crystal struct... The novel benzo-18-crown-6(B18-C-6)complex;{[Na(Bl8-C-6)]_(6)[Pt(SCN)_(6)]}[Pt(SCN)_(6)](SCN)_(2)(1)was synthesized and characterized by elemental analysis,IR spectrum and x-ray diffraction analysis.Thr crystal structure belongs to rhomobohedral,space group R-3 with cell dimesions:a=6=1.9933(3),c=2.9760(6)nm,α=β=90,γ=120°,V=10.240(3)nm^(3),Z=3,A,aclcd=1.564 g/cm^(3),F(000)=4908.1 is composed of one{[Na(B18-C-6)]_(6)[Pt(SCN)_(6)]}4+complex cation,one[Pt(SCN)_(6)]^(2-)complex anion and two SCN~anions.{[Na(B18-C-6)]_(6)[Pt(SCN)_(6)3}4+complex cation shows a three-dimensional network structure bridged by Na-O interactions between adjacent[Na(B18-C-6)]+units.The function of[Pt(SCN)_(6)]^(2-)complex anion and two SCN'anions are balancing charge in crystal. 展开更多
关键词 three-dimensional network crown ether Pt complex benzo-18-crown-6
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Reconstruction of caprine mandibular segmental defect by tissue engineered bone reinforced by titanium reticulum 被引量:3
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作者 席庆 步荣发 +1 位作者 刘洪臣 毛天球 《Chinese Journal of Traumatology》 CAS 2006年第2期67-71,共5页
Objective :To investigate the feasibility of using natural poritos as scaffolds in bone tissue engineering (TE) and repair of caprine mandibular segmental defect with titanium reticulum reinforced. Methods: Natur... Objective :To investigate the feasibility of using natural poritos as scaffolds in bone tissue engineering (TE) and repair of caprine mandibular segmental defect with titanium reticulum reinforced. Methods: Natural poritos with a pore of 190-230 μm in size and porosity of about 50 %-65 % was molded into the shape of granules 5 mm × 5 mm × 5 mm in size. Expanded autologous caprine marrow mesenchymal stem cells were induced by recombinant human morphogenetic protein-2 (rhBMP2) to improve osteoblastic phenotype. Then marrow derived osteoblasts were seeded into poritos in density of 4 × 10^7/ml and incubated in vitro for 48 hours prior to implantation. Then osteoblastic cells/poritos complexes were implanted into mandibular defect and the defect was reinforced by titanium reticulum. Implantation of poritos alone acted as the control. Bone regeneration was assessed 4, 8, 16 weeks after implantation using roentgenographie analysis and histological observation was done after 16 weeks. Results: New bone could be observed histologically on the surface and in the pores of natural coral in all specimens in the cell-seeding group, whereas in the control group there was no evidence of osteogenesis process in the center of the construction. The results showed that new bone grafts were successfully restored 16 weeks after implantation. Conclusions: This study suggests the feasibility of using porous coral as scaffold material transplanted with marrow derived osteoblasts by TE method. By means of titanium reticulum reinforcement, mandibular defect could be successfully restored. It shows the potentiality of using this method for the reconstruction of bone defect in cfinic. 展开更多
关键词 Tissue engineering MANDIBLE Titanium reticulum
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Strength behavior and collapse of spatial-reticulated structures under multi-support excitation 被引量:4
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作者 YE JiHong ZHANG ZhiQiang CHU Ye 《Science China(Technological Sciences)》 SCIE EI CAS 2011年第6期1624-1638,共15页
Under strong shocks,long-span spatial-latticed structures may collapse due to dynamic instability or strength failure.The elasto-plastic dynamic behaviors of three spatiallatticed structures,including two double-layer... Under strong shocks,long-span spatial-latticed structures may collapse due to dynamic instability or strength failure.The elasto-plastic dynamic behaviors of three spatiallatticed structures,including two double-layer cylindrical shells and a spheri-cal shell used for the 2008 Olympic Games in Beijing,were quantitatively examined under multi-support excitation(MSE) and uniform support excitation(USE).Numerical analyses described several important parameters such as the peak acceleration and displacement responses at key joints,the number and distribution of plastic elements,and the deformation of the shell at the moment of collapse.Results of the analysis revealed the features and the failure mechanism of the spatial-latticed structures under MSE and USE.In both scenarios,the double-layer reticulated shell collapsed in the "overflow" mode,collapse was govrned by the number of invalid plastic elements rather than the total number of plastic elements,and the collapse of the structure began with damage to certain local regions near the supports.By comparing the numbers and distributions of the plastic members under MSE to those under USE,it was observed that the plastic members spread more sufficiently and the internal forces were more uniform under MSE,especially for lower apparent velocities in soils.Due to the effects of pseudo-static displacement,the stresses in members near supports under MSE were higher than those under USE.These regions are prone to failure during earthquakes and deserve special attention in the seismic design of reticulated structures. 展开更多
关键词 multiple support excitation(MSE) uniform support excitation(USE) elastic-plastic time history analysis spatial-latticed structure strength failure
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