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美国大都市区划分指标体系的百年演变 被引量:22
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作者 罗海明 张媛明 《国际城市规划》 2007年第5期58-64,共7页
美国大都市区划分指标体系已有近百年历史,从数据可比性和指标体系繁简性角度,可将其划分为形成、发展和成熟三个阶段,并从中央核、流测度、大都市区特征和基本地理单元四个方面,对三个阶段指标体系的特征分别进行了分析。在此基础之上... 美国大都市区划分指标体系已有近百年历史,从数据可比性和指标体系繁简性角度,可将其划分为形成、发展和成熟三个阶段,并从中央核、流测度、大都市区特征和基本地理单元四个方面,对三个阶段指标体系的特征分别进行了分析。在此基础之上,本文对三阶段指标体系特征进行了比较研究,归纳出7点可供借鉴的规律:与郊区化发展阶段相对应、与大都市区发展阶段相对应、总体设计思路保持一致、中央核人口规模门槛值降低、流测度指标不可或缺、大都市区特征逐步弱化和以县为基本地理单元。 展开更多
关键词 大都市区 划分指标体系 中央核 流测度 大都市区特征 基本地理单元
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首都大型科学仪器设备利用与共享评价初探 被引量:11
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作者 王海峰 王晋 杨丽 《中国科技论坛》 CSSCI 北大核心 2014年第9期11-15,共5页
本文构建了北京地区大型科学仪器设备利用和共享评价指标体系,对利用和共享情况进行了评价。结果表明,北京地区新增设备利用率低于总体设备利用率,新增设备对外服务共享率低于总体对外服务共享率,新增设备的利用水平和共享水平均有待提... 本文构建了北京地区大型科学仪器设备利用和共享评价指标体系,对利用和共享情况进行了评价。结果表明,北京地区新增设备利用率低于总体设备利用率,新增设备对外服务共享率低于总体对外服务共享率,新增设备的利用水平和共享水平均有待提升。中央单位的利用水平明显高于市属单位,但市属单位在参与共享的设备原值占比和对外服务共享率上具有优势。中央单位应进一步推进更多的大型科学仪器设备开放共享,市属单位应在设备利用、设备信息公开和跨区域共享上进一步提升。 展开更多
关键词 大型科学仪器设备 中央单位 市属单位 利用 共享
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一种基于CAN总线的集散型火灾报警控制系统 被引量:8
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作者 张专成 邹涛 +1 位作者 冯立杰 赖玉强 《微计算机信息》 北大核心 2006年第05Z期29-31,共3页
提出了一种基于CAN总线的集散型火灾报警控制系统的设计方案,系统以AT89C51单片机为节点控制器,MCP2510为总线控制器,MCP2551为总线收发器。文章主要介绍了AT89C51与MCP2510的SPI接口实现方法,以及MCP2510的初始化方法。
关键词 CAN现场总线 MCP2510 集中机 区域机
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Lowing the energy loss of organic solar cells by molecular packing engineering via multiple molecular conjugation extension 被引量:6
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作者 Hongbin Chen Yalu Zou +12 位作者 Huazhe Liang Tengfei He Xiaoyun Xu Yunxin Zhang Zaifei Ma Jing Wang Mingtao Zhang Quanwen Li Chenxi Li Guankui Long Xiangjian Wan Zhaoyang Yao Yongsheng Chen 《Science China Chemistry》 SCIE EI CSCD 2022年第7期1362-1373,共12页
The central unit(benzo[c][1,2,5]thiadiazole) in Y6 series of molecules plays a determining role in their unique intermolecular packing for a three-dimensionally(3D) network, largely endowing their organic solar cells(... The central unit(benzo[c][1,2,5]thiadiazole) in Y6 series of molecules plays a determining role in their unique intermolecular packing for a three-dimensionally(3D) network, largely endowing their organic solar cells(OSCs) with so far the best power conversion efficiencies(PCEs) and also largely suppressed energy losses(Eloss). Despite its vital role in molecular packing, very few explorations for central unit have been conducted due to possibly the constructing challenge of central heterocyclic units.Herein, a highly efficient acceptor-donor-acceptor(A-D-A) type electron acceptor, CH17, has been designed and constructed,featured with a prominent π extension in both directions of the central and end units with respect to Y6 series. Such a multiple and much enhanced conjugation extension in CH17 enables a much more effective and compact 3D molecular packing compared with that of Y6 supported by X-ray single crystal and other analysis, mainly caused by a newly observed distinctive dual “end unit to central unit” packing mode. This much favorable molecular packing, also kept in its blends with donor materials, leads a larger electron and hole transfer integrals and hence much improved charge transport, and reduced energetic disorders in CH17blends. More importantly, the observed upshifted charge transfer(CT) state of CH17 blends compared with that of Y6, due to its increased molecular conjugation extension in both directions, further enhances the hybridization between its CT and local exciton(LE) states, resulting in higher luminescence efficiency, much suppressed non-radiative recombination loss and smaller Elosswith respect to that of Y6. Consequently, an excellent PCE of 17.84% is achieved with PM6 as the donor in a binary device compared with a PCE of 16.27% for the controlled Y6 device. Furthermore, a further improved PCE of 18.13% is achieved by CH17-based ternary single-junction OSCs along with a markedly reduced Elossof 0.49 e V and larger open-circuit voltage(Voc) of0.89 V, compared with that(16.27% of 展开更多
关键词 organic solar cells A-D-A electron acceptor reduced Eloss central unit multiple conjugation extension molecular packing
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Delicate chemical structure regulation of nonfullerene acceptor for efficient and large thickness organic solar cells
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作者 Zhe Zhang Wanying Feng +9 位作者 Yunxin Zhang Shaohui Yuan Yuyang Bai Peiran Wang Zhaoyang Yao Chenxi Li Tainan Duan Xiangjian Wan Bin Kan Yongsheng Chen 《Science China Chemistry》 SCIE EI CAS CSCD 2024年第5期1596-1604,共9页
Inspired by the success of CH-series acceptors, a small-molecular acceptor, CH-Tz was reported by adopting a new conjugationextended electron-deficient unit([1,2,5]thiadiazolo[3,4-b]pyrazine) on the central core. Owin... Inspired by the success of CH-series acceptors, a small-molecular acceptor, CH-Tz was reported by adopting a new conjugationextended electron-deficient unit([1,2,5]thiadiazolo[3,4-b]pyrazine) on the central core. Owing to the enhanced inter-/intramolecular interactions, CH-Tz exhibited near-infrared absorption and an effective three-dimensional molecular packing network in its single crystal. When blended with polymer donor PM6, the binary device achieved a high power conversion efficiency(PCE) of 18.54%, with a notable short-circuit current density(J_(sc)) of 27.54 m A cm-2and an excellent fill factor(FF) over 80%,which can be partly ascribed to the balanced charge transport properties in the blend film. After employing D18-Cl as the third component, an enhanced PCE of 18.85% was achieved due to a more obvious fiber network. Impressively, the CH-Tz-based OSC devices show excellent thermal stability and thickness insensitivity. Record-breaking Jscof 28.92 m A cm-2was reached for PM6:D18-Cl:CH-Tz ternary device with a thickness of 560 nm. Besides, CH-Tz shows potential in fabricating multicomponent high-performance organic solar cells, where over 19% efficiency could be realized in the quaternary device. Our work advances the strong influence of electron-deficient central units on molecular photovoltaic properties and guides the design of acceptors for stable and large-thickness organic solar cells. 展开更多
关键词 organic solar cells non-fullerene acceptor central unit large thickness molecular packing
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Strategy of constructing virtual peaking unit by public buildings’central air conditioning loads for day-ahead power dispatching 被引量:6
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作者 Chenxing YANG Qingshan XU Xufang WANG 《Journal of Modern Power Systems and Clean Energy》 SCIE EI 2017年第2期187-201,共15页
With the gradually widely usage of the air conditioning(AC) loads in developing countries, the urban power grid load has swiftly increased over the past decade.Especially in China, the AC load has accounted for over30... With the gradually widely usage of the air conditioning(AC) loads in developing countries, the urban power grid load has swiftly increased over the past decade.Especially in China, the AC load has accounted for over30% of the maximum load in many cities during summer.This paper proposes a scheme of constructing a virtual peaking unit(VPU) by public buildings’ cool storage central AC(CSCAC) systems and non-CSCAC(NCSCAC)systems for the day-ahead power network dispatching(DAPND). Considering the accumulation effect of different meteorological parameters, a short term load forecasting method of public building’s central AC(CAC) baseline load is firstly discussed. Then, a second-order equivalent thermal parameters model is established for the public building’s CAC load. Moreover, the novel load reduction control strategies for the public building’s CSCAC system and the public building’s NCSCAC system are respectively presented. Furthermore, based on the multiple-rank control strategy, the model of the DAPND with the participation of a VPU is set up. The VPU is composed of large-scale regulated public building’s CAC loads. To demonstrate the effectiveness of the proposed strategy, results of a sample study on a region in Nanjing which involves 22 public buildings’ CAC loads are described in this paper. Simulated results show that, by adopting the proposed DAPND scheme, the power network peak load in the region obviously decreases with a small enough deviation between the regulated load value and the dispatching instruction of the VPU. The total electricity-saving amount accounts for7.78% of total electricity consumption of the VPU before regulation. 展开更多
关键词 central air conditioning Peak load shedding Day-ahead power network dispatching Virtual peaking unit Schedulable capacity
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电力系统单元分布式RTU相对于集中式RTU的优势及其应用 被引量:1
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作者 关永前 《长沙水电师院学报(自然科学版)》 2001年第4期55-57,共3页
对比传统集中式RTU(远方控制单元 ) ,提出了单元分布式RTU的设计思路以及其在安装、运行、维护、扩容等方面的优势 .在进行性能、经济等方面的比较后 ,可以认定 ,单元分布式RTU以其安装简便、运行稳定、易于维护、扩展性好等优势 ,必将... 对比传统集中式RTU(远方控制单元 ) ,提出了单元分布式RTU的设计思路以及其在安装、运行、维护、扩容等方面的优势 .在进行性能、经济等方面的比较后 ,可以认定 ,单元分布式RTU以其安装简便、运行稳定、易于维护、扩展性好等优势 ,必将成为传统集中式RTU的替代品 ,将被广泛应用于综合自动化变电站中 . 展开更多
关键词 RTU 远方控制单元 集中式 单元分布式 综合自动化变电站 电力系统 设计
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渤中19-6气田封隔器金属材料的腐蚀适应性评价 被引量:1
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作者 张明 龚宁 +5 位作者 马英文 程飞 张智 严永博 钟显康 霍宏博 《腐蚀与防护》 CAS CSCD 北大核心 2023年第2期45-52,81,共9页
在模拟渤中19-6气田井下工况环境中对35CrMo碳钢、42CrMo碳钢、HS110抗硫钢、13Cr不锈钢、13Cr超级不锈钢(13CrS)、2205双相不锈钢等6种金属材料进行了腐蚀试验,研究其腐蚀行为。通过失重法计算金属的腐蚀速率,采用扫描电镜(SEM)观察金... 在模拟渤中19-6气田井下工况环境中对35CrMo碳钢、42CrMo碳钢、HS110抗硫钢、13Cr不锈钢、13Cr超级不锈钢(13CrS)、2205双相不锈钢等6种金属材料进行了腐蚀试验,研究其腐蚀行为。通过失重法计算金属的腐蚀速率,采用扫描电镜(SEM)观察金属腐蚀形貌,采用X射线光电子能谱仪(XPS)分析腐蚀产物成分。结果表明:HS110抗硫钢、35CrMo碳钢、42CrMo碳钢、13Cr不锈钢、13Cr超级不锈钢、2205双相不锈钢的腐蚀速率依次降低,且所有钢在液相中的腐蚀速率高于其在气相中的腐蚀速率。渤中19-6气田封隔器的中心管推荐选用13Cr超级不锈钢和2205双相不锈钢,卡瓦等功能性部件推荐选用42CrMo碳钢。 展开更多
关键词 渤中19-6 腐蚀行为 腐蚀速率 封隔器 中心管 功能性部件
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A new approach for real time object detection and tracking on high resolution and multi-camera surveillance videos using GPU 被引量:4
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作者 Mohammad Farukh Hashmi Ritu Pal +1 位作者 Rajat Saxena Avinash G.Keskar 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第1期130-144,共15页
High resolution cameras and multi camera systems are being used in areas of video surveillance like security of public places, traffic monitoring, and military and satellite imaging. This leads to a demand for computa... High resolution cameras and multi camera systems are being used in areas of video surveillance like security of public places, traffic monitoring, and military and satellite imaging. This leads to a demand for computational algorithms for real time processing of high resolution videos. Motion detection and background separation play a vital role in capturing the object of interest in surveillance videos, but as we move towards high resolution cameras, the time-complexity of the algorithm increases and thus fails to be a part of real time systems. Parallel architecture provides a surpass platform to work efficiently with complex algorithmic solutions. In this work, a method was proposed for identifying the moving objects perfectly in the videos using adaptive background making, motion detection and object estimation. The pre-processing part includes an adaptive block background making model and a dynamically adaptive thresholding technique to estimate the moving objects. The post processing includes a competent parallel connected component labelling algorithm to estimate perfectly the objects of interest. New parallel processing strategies are developed on each stage of the algorithm to reduce the time-complexity of the system. This algorithm has achieved a average speedup of 12.26 times for lower resolution video frames(320×240, 720×480, 1024×768) and 7.30 times for higher resolution video frames(1360×768, 1920×1080, 2560×1440) on GPU, which is superior to CPU processing. Also, this algorithm was tested by changing the number of threads in a thread block and the minimum execution time has been achieved for 16×16 thread block. And this algorithm was tested on a night sequence where the amount of light in the scene is very less and still the algorithm has given a significant speedup and accuracy in determining the object. 展开更多
关键词 central processing unit (CPU) graphics processing unit (GPU) MORPHOLOGY connected component labelling (CCL)
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Mechanism of Fast Data Retransmission in CU-DU Split Architecture of 5G NRG 被引量:2
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作者 HUANG He LIU Yang +2 位作者 LIU Zhuang HAN Jiren GAO Yin 《ZTE Communications》 2018年第3期40-44,共5页
The 5G radio access network (RAN) architectm'e is supposed to be split into the central unit (CU) and the distributed unit (DU) in order to support more flexible transport networks and provide enhanced user exp... The 5G radio access network (RAN) architectm'e is supposed to be split into the central unit (CU) and the distributed unit (DU) in order to support more flexible transport networks and provide enhanced user experience. However, such functional split may also introduce some new technical issues. In this pa- per, we study the data fast retransmission issue introduced by this functional split in different scenarios and solutions are provided to handle this issue. With the fast data retransmis- sion mechanism proposed in this paper, the retransmitted da- ta packets could be identified and handled with high priority. In this way, the data delivery between the CU and DU in 5G RAN is assured. 展开更多
关键词 5G RAN central unit distributed unit fast retransmission
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High efficiency ternary organic solar cells enabled by compatible dual-donor strategy with planar conjugated structures 被引量:4
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作者 Sanhui Chen Tingting Yan +7 位作者 Billy Fanady Wei Song Jinfeng Ge Qiang Wei Ruixiang Peng Guohui Chen Yingping Zou Ziyi Ge 《Science China Chemistry》 SCIE EI CAS CSCD 2020年第7期917-923,共7页
Ternary organic solar cells(OSCs) have received extensive attention for improving the power conversion efficiency(PCE) of organic photovoltaics(OPVs). In this work, a novel donor material(ECTBD) consisting of benzodit... Ternary organic solar cells(OSCs) have received extensive attention for improving the power conversion efficiency(PCE) of organic photovoltaics(OPVs). In this work, a novel donor material(ECTBD) consisting of benzodithiophene(BDT) central electron donor unit was developed and synthesized. The small molecular donor has the same central unit as PM6. The addition of ECTBD into PM6:Y6 system could improve the morphology of active blend layer. In addition, ECTBD showed good morphologically compatibility when blending with PM6:Y6 host, resulting in the improvement of fill factor and current density. As a result, the ternary devices based on PM6:ECTBD:Y6 ternary system achieved a highest PCE of 16.51% with fill factor of 76.24%, which was much higher than that of the binary devices(15.7%). Overall, this work provided an effective strategy to fabricate highly efficient ternary organic solar cells through design of the novel small molecular donor as the third component. 展开更多
关键词 ternary organic solar cells small molecule donor high fill-factor the same central unit strategy MORPHOLOGY
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LARGEST ALTYN TAGH LITHOSPHERIC SHEAR FAULT IN CENTRAL ASIA 被引量:1
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作者 Xu Zhiqin 1, Yang Jingsui 1, Zhang Jianxin 1, Jiang Mei 1, Li Haibing 1,Liou J.G. 2 2 Department of Geological & Environmental Sciences,St 《地学前缘》 EI CAS CSCD 2000年第S1期231-232,共2页
The Altyn Tagh fault (ATF) extending in NEE—SWW direction lying at the northwestern boundary of Qinghai—Tibet plateau is the largest strike\|slip fault in Central Asia. On the basis of recent geologic mapping and de... The Altyn Tagh fault (ATF) extending in NEE—SWW direction lying at the northwestern boundary of Qinghai—Tibet plateau is the largest strike\|slip fault in Central Asia. On the basis of recent geologic mapping and detailed study of lithotectonic characteristics for the paleotectonic units at the two sides of the Altyn Tagh Fault ( Altun Mt. to west and the Qilian Mt. to east ) we propose that the paleotectonic units in the Altun Mt. can be correlated with those in the Qilian Mt. assuming 400km left\|lateral displacement for the Altyn Tagh fault. Natural seismic data across the Altun Mt. indicate that the Altyn Tagh fault is a lithospheric shear fault and the lithospheric shearing is probably related to southward intracontinental oblique subduction of the Tarim terrane beneath the Altun Mt.1\ Comparison of the major paleotectonic units at the two sides of the Altyn Tagh fault\;(1) The Alxa\|Dunhuang Massif:The Alxa massif lying at the southern margin of the Sino\|Korean craton consists mainly of an Early Proterozoic basement including high\|grade and middle\|grade metamorphic rocks, which were intruded by granite at 1719Ma. The Paleozoic passive margin sediments is well developed. In the Altun Mt., the Early Proterozoic and late Archean basement of the Duhuang massif includes high\|grade and middle\|grade metamorphic rocks dating 2789Ma (Sm\|Nd method) and 2405Ma (U\|Pb method). 展开更多
关键词 LITHOSPHERIC SHEAR FAULT paleotectonic unit SEISMIC the Altyn Tagh FAULT central ASIA
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Exogenous platelet-derived growth factor improves neurovascular unit recovery after spinal cord injury 被引量:3
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作者 Lu-Xia Ye Ning-Chen An +10 位作者 Peng Huang Duo-Hui Li Zhi-Long Zheng Hao Ji Hao Li Da-Qing Chen Yan-Qing Wu Jian Xiao Ke Xu Xiao-Kun Li Hong-Yu Zhang 《Neural Regeneration Research》 SCIE CAS CSCD 2021年第4期757-763,共7页
The blood-spinal cord barrier plays a vital role in recovery after spinal cord injury.The neurovascular unit concept emphasizes the relationship between nerves and vessels in the brain,while the effect of the blood-sp... The blood-spinal cord barrier plays a vital role in recovery after spinal cord injury.The neurovascular unit concept emphasizes the relationship between nerves and vessels in the brain,while the effect of the blood-spinal cord barrier on the neurovascular unit is rarely reported in spinal cord injury studies.Mouse models of spinal cord injury were established by heavy object impact and then immediately injected with plateletderived growth factor(80μg/kg)at the injury site.Our results showed that after platelet-derived growth factor administration,spinal cord injury,neuronal apoptosis,and blood-spinal cord barrier permeability were reduced,excessive astrocyte proliferation and the autophagyrelated apoptosis signaling pathway were inhibited,collagen synthesis was increased,and mouse locomotor function was improved.In vitro,human umbilical vein endothelial cells were established by exposure to 200μM H2O2.At 2 hours prior to injury,in vitro cell models were treated with 5 ng/mL platelet-derived growth factor.Our results showed that expression of blood-spinal cord barrier-related proteins,including Occludin,Claudin 5,andβ-catenin,was significantly decreased and autophagy was significantly reduced.Additionally,the protective effects of platelet-derived growth factor could be reversed by intraperitoneal injection of 80 mg/kg chloroquine,an autophagy inhibitor,for 3 successive days prior to spinal cord injury.Our findings suggest that platelet-derived growth factor can promote endothelial cell repair by regulating autophagy,improve the function of the blood-spinal cord barrier,and promote the recovery of locomotor function post-spinal cord injury.Approval for animal experiments was obtained from the Animal Ethics Committee,Wenzhou Medical University,China(approval No.wydw2018-0043)in July 2018. 展开更多
关键词 AUTOPHAGY blood-spinal cord barrier central nervous system locomotor function neurovascular unit platelet-derived growth factor spinal cord spinal cord injury
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Implementing Delay Multiply and Sum Beamformer on a Hybrid CPU-GPU Platform for Medical Ultrasound Imaging Using Open MP and CUDA 被引量:2
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作者 Ke Song Paul Liu Dongquan Liu 《Computer Modeling in Engineering & Sciences》 SCIE EI 2021年第9期1133-1150,共18页
Anovel beamforming algorithmnamed Delay Multiply and Sum(DMAS),which excels at enhancing the resolution and contrast of ultrasonic image,has recently been proposed.However,there are nested loops in this algorithm,so t... Anovel beamforming algorithmnamed Delay Multiply and Sum(DMAS),which excels at enhancing the resolution and contrast of ultrasonic image,has recently been proposed.However,there are nested loops in this algorithm,so the calculation complexity is higher compared to the Delay and Sum(DAS)beamformer which is widely used in industry.Thus,we proposed a simple vector-based method to lower its complexity.The key point is to transform the nested loops into several vector operations,which can be efficiently implemented on many parallel platforms,such as Graphics Processing Units(GPUs),and multi-core Central Processing Units(CPUs).Consequently,we considered to implement this algorithm on such a platform.In order to maximize the use of computing power,we use the GPUs andmulti-core CPUs inmixture.The platform used in our test is a low cost Personal Computer(PC),where a GPU and a multi-core CPU are installed.The results show that the hybrid use of a CPU and a GPU can get a significant performance improvement in comparison with using a GPU or using amulti-core CPU alone.The performance of the hybrid system is increased by about 47%–63%compared to a single GPU.When 32 elements are used in receiving,the fame rate basically can reach 30 fps.In the best case,the frame rate can be increased to 40 fps. 展开更多
关键词 BEAMFORMING delay multiply and sum graphics processing unit multi-core central processing unit
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防御性军事战地远程控制系统的设计
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作者 周颖 《兵工自动化》 2004年第6期3-5,共3页
防御性军事战地远程控制系统硬件由指控单元、中央单元、直流电源和外设单元组成。系统软件包括指控单元绘图、指控和中央单元间通信、中央单元和外设单元间通信、外设与军备间指令等界面。每个外设单元控制与它相连接 20m 远的 16 路军... 防御性军事战地远程控制系统硬件由指控单元、中央单元、直流电源和外设单元组成。系统软件包括指控单元绘图、指控和中央单元间通信、中央单元和外设单元间通信、外设与军备间指令等界面。每个外设单元控制与它相连接 20m 远的 16 路军备,操作员根据军备功能决定传送信息给中央单元,经解码后传送指令到外设单元并控制电源设备、指挥军备的爆炸。 展开更多
关键词 远程控制 指控单元 中央单元 外设单元 军备
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A neurovascular unit-on-a-chip:culture and differentiation of human neural stem cells in a three-dimensional microfluidic environment
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作者 Wen-Juan Wei Ya-Chen Wang +2 位作者 Xin Guan Wei-Gong Chen Jing Liu 《Neural Regeneration Research》 SCIE CAS CSCD 2022年第10期2260-2266,共7页
Biological studies typically rely on a simple monolayer cell culture,which does not reflect the complex functional characteristics of human tissues and organs,or their real response to external stimuli.Microfluidic te... Biological studies typically rely on a simple monolayer cell culture,which does not reflect the complex functional characteristics of human tissues and organs,or their real response to external stimuli.Microfluidic technology has advantages of high-throughput screening,accurate control of the fluid velocity,low cell consumption,long-term culture,and high integration.By combining the multipotential differentiation of neural stem cells with high throughput and the integrated characteristics of microfluidic technology,an in vitro model of a functionalized neurovascular unit was established using human neural stem cell-derived neurons,astrocytes,oligodendrocytes,and a functional microvascular barrier.The model comprises a multi-layer vertical neural module and vascular module,both of which were connected with a syringe pump.This provides controllable conditions for cell inoculation and nutrient supply,and simultaneously simulates the process of ischemic/hypoxic injury and the process of inflammatory factors in the circulatory system passing through the blood-brain barrier and then acting on the nerve tissue in the brain.The in vitro functionalized neurovascular unit model will be conducive to central nervous system disease research,drug screening,and new drug development. 展开更多
关键词 (neural)differentiation ASTROCYTE blood-brain barrier brain microvascular endothelial cells central nervous system microfluidics neural stem cells NEURON neurovascular unit OLIGODENDROCYTE organ-on-a-chip
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一种多终端主从式网络协议的研究 被引量:1
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作者 谭家玉 袁力强 孙雅丽 《哈尔滨商业大学学报(自然科学版)》 CAS 1999年第3期29-32,36,共5页
本文提出一种简单实用的多终端主从式网络协议,适用于较多终端的一主多从结构数据采集和自动控制系统及局部网络中。
关键词 协议 终端 主机 集中器 报文 通信 轮询
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基于MCS-51单片机的现场总线型分布式火灾报警控制系统
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作者 黄天录 张专成 +1 位作者 庞新法 汪成龙 《现代电子技术》 2006年第23期97-100,共4页
介绍了一种基于MCS-51单片机的现场总线型分布式火灾报警控制系统。该系统具有以下特点:用简单的机器语言表示最基本的逻辑原型,为联动编程提供了良好的人机界面;采用现场总线结构,容易实现网络集成;网络通信采用同步计数顺序争用多址... 介绍了一种基于MCS-51单片机的现场总线型分布式火灾报警控制系统。该系统具有以下特点:用简单的机器语言表示最基本的逻辑原型,为联动编程提供了良好的人机界面;采用现场总线结构,容易实现网络集成;网络通信采用同步计数顺序争用多址接入技术,使集中机摆脱了对区域机的巡访,增强了系统的分布化程度,提高了设备的利用率。系统结构灵活、使用方便,可满足大、中、小各种规模的火灾报警及消防控制的要求。 展开更多
关键词 现场总线 分布式 集中机 区域机
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认识CPU的接口
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作者 李国良 《电脑知识与技术(过刊)》 2005年第6期58-59,共2页
我们都知道,CPU即中央处理单元,是英文Central Processing Unit的缩写,是整个系统的核心,也是整个系统最高的执行单位。它的作用是负责整个系统指令的执行,数学与逻辑的运算,数据的存储与传送,以及对内对外输入与输出的控制。因... 我们都知道,CPU即中央处理单元,是英文Central Processing Unit的缩写,是整个系统的核心,也是整个系统最高的执行单位。它的作用是负责整个系统指令的执行,数学与逻辑的运算,数据的存储与传送,以及对内对外输入与输出的控制。因为CPU是决定电脑性能的核心部件.以前人们就以它来判定电脑的档次,于是就有了486、586、PII称呼。事实上.生产CPU的不同厂商.都为自己的产品规定了不同的名称。如Intel公司称作奔腾.AMD公司的称作K6等。目前CPU的接口都是针脚式接口.对应到主板上就有相应的插槽类型。CPU接口类型不同.在插孔数、大小、形状都有变化。所以不能互相接插。 展开更多
关键词 CPU central Intel公司 中央处理单元 AMD公司 unit 系统指令 核心部件 电脑性能 接口类型 PII 执行 传送 数据 奔腾 插槽 主板
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Trends of central line-associated bloodstream infections in the intensive care unit in the Kingdom of Bahrain:Four years’experience
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作者 Safaa Al-Khawaja Nermin Kamal Saeed +2 位作者 Sanaa Al-khawaja Nashwa Azzam Mohammed Al-Biltagi 《World Journal of Critical Care Medicine》 2021年第5期220-231,共12页
BACKGROUND The central venous line is an essential component in monitoring and managing critically ill patients.However,it poses patients with increased risks of severe infections with a higher probability of morbidit... BACKGROUND The central venous line is an essential component in monitoring and managing critically ill patients.However,it poses patients with increased risks of severe infections with a higher probability of morbidity and mortality.AIM To define the trends of the rates of central line-associated bloodstream infections(CLABSI)over four years,its predicted risk factors,aetiology,and the antimicrobial susceptibility of the isolated pathogens.METHODS The study was a prospective case-control study,performed according to the guidelines of the Center for Disease Control surveillance methodology for CLABSI in patients admitted to the adult intensive care unit(ICU)and auditing the implementation of its prevention bundle.RESULTS Thirty-four CLABSI identified over the study period,giving an average CLABSI rate of 3.2/1000 central line days.The infection's time trend displayed significant reductions over time concomitantly with the CLABSI prevention bundle's reinforcement from 4.7/1000 central line days at the beginning of 2016 to 1.4/1000 central line days by 2018.The most frequently identified pathogens causing CLABSI in our ICU were gram-negative organisms(59%).The most common offending organisms were Acinetobacter,Enterococcus,and Staphylococcus epidermidis,each of them accounted for 5 cases(15%).Multidrug-resistant organisms contributed to 56%of CLABSI.Its rate was higher when using femoral access and longer hospitalisation duration,especially in the ICU.Insertion of the central line in the non-ICU setting was another identified risk factor.CONCLUSION Implementing the prevention bundles reduced CLABSI significantly in our ICU.Implementing the CLABSI prevention bundle is crucial to maintain a substantial reduction in the CLABSI rate in the ICU setting. 展开更多
关键词 Bloodstream infection central line Intensive Care unit MICROBIOLOGY Prevention bundle Kingdom of Bahrain
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