检索结果-南通市图书馆

Particle convective heat transfer near the wall in a supercritical water fluidized bed by single particle model coupled with CFD-DEM

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2023年第2期73卷 47-58页

作者： tianning zhang Zhen Wan Youjun Lu State Key Laboratory of Multiphase Flow in Power Engineering(SKLMFPE) Xi'an Jiaotong UniversityXi'an710049ShaanxiChina Xi'an Electronic Engineering Research Institute Xi'an710100ShaanxiChina

Supercritical water fluidized bed(SCWFB)is a promising reactor to gasify biomass or *** optimization design is closely related to wall-to-bed heat transfer,where particle convective heat transfer plays an important *** paper evaluates the particle convective heat transfer coefficient(h_(pc))at the wall in SCWFB using the single particle *** critical parameters in the single particle model which is difficult to get experimentally are obtained by the computational fluid dynamics-discrete element method(CFD-DEM).The contact statistics related to particle-to-wall heat transfer,such as contact number and contact distance,are also *** results show that particle residence time(τ),as the key parameter to evaluate h_(pc),is found to decrease with rising velocity,while increase with larger thermal boundary layer thickness.τfollows a gamma function initially adopted in the gas-solid fluidized bed,making it possible to evaluate h_(pc) in SCWFB by a simplified single particle *** theoretical predicted h_(pc) tends to increase with rising thermal gradient thickness at a lower velocity(1.5 U_(mf)),while first decreases and then increases at higher velocity(1.75 and 2 U_(mf)).h_(pc) occupies 30%-57%of the overall wall-to-bed heat transfer coefficient for a particle diameter of 0.25 *** results are helpful to predict the overall wall-to-bed heat transfer coefficient in SCWFB combined with a reasonable fluid convective heat transfer model from a theoretical perspective.

关键词： Supercritical water Fluidized bed Particle residence time Discrete element method Single particle model

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

多喷嘴喷雾冷却表面传热特性实验研究

化工学报 2024年第1期75卷 231-241页

作者：李晓阳李东陶明磊周致富张灵怡苏力争张天宁李智陈斌西安交通大学动力工程多相流国家重点实验室陕西西安710049 西安电子工程研究所陕西西安710100

低沸点制冷剂(R134a)喷雾冷却能快速降低表面温度,在高性能芯片等电子设备热管理、生物医学中均具有广泛应用,可实现喷雾表面的低温高效散热。多喷嘴喷雾冷却可实现较大冷却表面的均匀冷却及冷量的灵活调控。搭建了制冷剂喷雾冷却实验台... 详细信息

低沸点制冷剂(R134a)喷雾冷却能快速降低表面温度,在高性能芯片等电子设备热管理、生物医学中均具有广泛应用,可实现喷雾表面的低温高效散热。多喷嘴喷雾冷却可实现较大冷却表面的均匀冷却及冷量的灵活调控。搭建了制冷剂喷雾冷却实验台,研究了多喷嘴喷雾冷却表面传热特性,并分析了喷嘴的孔径、间距、高度、喷雾时间和喷雾压力等因素对多喷嘴喷雾冷却表面传热特性的影响。结果表明:喷嘴孔径对冷却均匀性影响最大,其次是喷嘴间距,适当的喷嘴孔径(0.4 mm)和间距(11 mm)能使制冷剂喷雾在表面合理分布,最低温Tmin能达到最小值;10 mm喷嘴高度和1.2 MPa喷雾压力可以使液滴充分雾化并延长有效冷却时间。

关键词：喷雾冷却瞬态传热电子热管理 R134a

维普期刊数据库博看期刊

Plasmonic semiconductor nanogroove array enhanced broad spectral band millimetre and terahertz wave detection

在线全文

学校读者我要写书评

暂无评论

Light(Science & Applications) 2021年第4期10卷 600-609页

作者： Jinchao Tong Fei Suo tianning zhang Zhiming Huang Junhao Chu Dao Hua zhang School of Electrical and Electronic Engineering Nanyang Technological UniversityNanyang Avenue639798 SingaporeSingapore State Key Laboratory of Infrared Physics Shanghai Institute of Technical

High-performance uncooled millimnetre and terahertz wave detectors are required as a building block for a wide range of *** state-of-the art technologies,however,are plagued by low sensitivity,narrow spectral bandwidth,and complicated ***,we report semiconductor surface plasmon enhanced high-performance broadband millimetre and terahertz wave detectors which are based on nanogroove InSb array epitaxially grown on GaAs substrate for room temperature *** making a nanogroove array in the grown InSb layer,strong millimetre and terahertz wave surface plasmon polaritons can be generated at the InSb-air interfaces,which results in significant improvement in detecting performance.A noise equivalent power(NEP)of 2.2× 10^(-14)WHz^(-1/2) or a detectivity(D)of 2.7× 10^(12)cmHz^(1/2) W^(-1) at 1.75 mm(0.171 THz)is achieved at room *** lowering the temperature to the thermoelectric cooling available 200 K,the corresponding NEP and D'of the nanogroove device can be improved to 3.8× 10^(-15)WHz^(-1/2) and 1.6× 10^(13) cm Hz^(-1/2) w^(-1),*** addition,such a single device can perform broad spectral band detection from 0.9 mm(0.330 THz)to 9.4 mm(0.032 THz).Fast responses of 3.5μs and 780 ns are achieved at room temperature and 200 K,*** high-performance millimnetre and terahertz wave photodetectors are useful for wide applications such as high capacity communications,walk-through security,biological diagnosis,spectroscopy,and remote *** addition,the integration of plasmonic semiconductor nanostructures paves a way for realizing high performance and multifunctional long-wavelength optoelectrical devices.

关键词： wave spectral terahertz

无线电地图辅助的多无人机部署与用户关联离线规划方法

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

电讯技术 2024年第8期64卷 1249-1256页

作者：万诺天王雨榕张恬宁马骋乾夏晓晨许魁中国人民解放军陆军工程大学通信工程学院南京210007 中国人民解放军31155部队南京210042

构建基于无人机基站(Unmanned Aerial Vehicle Base Station, UBS)的空地网络是解决移动通信网络覆盖等问题的重要途径。区别于地面移动通信网络,空地网络需要对UBS位置和用户关联进行联合优化。针对上述问题,首先通过构建二进制无线电... 详细信息

构建基于无人机基站(Unmanned Aerial Vehicle Base Station, UBS)的空地网络是解决移动通信网络覆盖等问题的重要途径。区别于地面移动通信网络,空地网络需要对UBS位置和用户关联进行联合优化。针对上述问题,首先通过构建二进制无线电地图(Binary Radio Map, BRM)使得UBS能够有效获取整个任务区域中用户位置关联的信道知识,在此基础上提出基于BRM的离线多UBS部署与用户关联联合规划方法。该方法以最大化网络效用函数为目标,通过互嵌套的启发式UBS部署位置搜索和基于匹配博弈的UBS-用户匹配实现UBS位置和用户关联的离线优化。在复杂城市环境下,相比于参考方案,所提方法可使得用户和速率性能提升10%~40%。

关键词：空地网络无人机基站部署用户关联二进制无线电地图

Temperature-dependent Photoluminescence of Silicon Nanocrystals Embedded in SiO2 Matrix

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2018年第4期34卷 513-516页

作者： zhang tianning zhang Kenan CHEN Xiren WANG Shuxia zhang Rongjun SHAO Jun CHEN Xin DAI Ning National Laboratory for Infrared Physics Shanghai Institute of Technical Physics Chinese Academy of Sciences Shanghai 200083 P. R. China Department of Optical Science and Engineering School of Information Science and Engineering Fudan University Shanghai 200433 P. R. China University of Chinese Academy of Sciences Beijing 100049 P. R. China

Nanostructured silicon plays a key role in the fidds of microelectronics, optoelectronics and photonics. Since near-infrared photolummescence（PL） was first observed in nanoporous silicon at room temperature, silicon nanocrystals（Si-NCs） have attracted considerable attention due to their tunable structures and properties. Considerable efforts have recently been devoted to obtaining deeper insight in the PL emission of colloidal and solid Si-NCs and the applications of these materials.

关键词： Silicon nanocrystal Photohtminescence Red-shift

市售肉品产志贺毒素大肠杆菌污染情况与耐药性分析——以泰安市为例

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

中国动物传染病学报 2024年第3期32卷 119-127页

作者：张天宁李文阳董鹏程毛衍伟杨啸吟罗欣朱立贤山东农业大学食品科学与工程学院泰安271000

产志贺毒素大肠杆菌(STEC)是一类产生一种或一种以上志贺毒素的具有强致病能力的食源性病原菌,现已是威胁人类健康的重要公共卫生问题之一。本文以山东省泰安市为调查点,对商超和农贸市场零售肉中产志贺毒素大肠杆菌(STEC)的污染情况进... 详细信息

产志贺毒素大肠杆菌(STEC)是一类产生一种或一种以上志贺毒素的具有强致病能力的食源性病原菌,现已是威胁人类健康的重要公共卫生问题之一。本文以山东省泰安市为调查点,对商超和农贸市场零售肉中产志贺毒素大肠杆菌(STEC)的污染情况进行调研,170份零售肉样品中9份样品检出STEC阳性,检出率为5.3%;其中商超和农贸市场的检出率分别为3.1%和6.7%,无显著性差异(P>0.05)。通过聚合酶链式反应(PCR)研究24株STEC分离菌株的血清型、毒力基因的携带情况。24株STEC中12株确定O血清型,分别为O26(10株)和O45(2株)。主要携带的毒力基因为stx1,hlyA(62.5%,15/24)和stx2(37.5%,9/24)基因,eaeA基因未检出。通过纸片扩散法对24株产志贺毒素大肠杆菌菌株进行耐药性检测,分离株对麦迪霉素的耐药率最高91.7%,对阿莫西林、氨苄西林的耐药率均为37.5%,对头孢西丁和多粘菌素敏感。综上所述,泰安市零售畜禽肉品中存在STEC不同程度的污染,其中猪肉、牛肉引起食源性疾病风险较大。本研究为相关部门加强市售肉品中STEC的监控提供一定的指导。

关键词：零售肉 STEC 耐药性血清型毒力基因

Vertically coupled ZnO nanorods on MoS2 monolayers with enhanced Raman and photoluminescence emission

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Nano Research 2015年第3期8卷 743-750页

作者： Kenan zhang Yun zhang tianning zhang Wenjing Dong Tiaoxing Wei Yan Sun Xin Chen Guozhen Shen Ning Dai National Laboratory for Infrared Physics Shanghai Institute of Technical Physics Chinese Academy of Sciences Shanghai 200083 China State Key Laboratory for Superlattices and Microstructures Institute of Semiconductors Chinese Academy of Sciences Beijing 100083 China

Hybrid structures composed of layered materials have received much attention due to their exceptional tunable optical, electronic and catalytic properties. Here, we describe a hydrothermal strategy for coupling vertical ZnO nanorods on MoS2 monolayers without a catalyst. These vapor-solid-grown MoS2 monolayers aid in growing vertical ZnO nanorods via epitaxy. Enhanced Raman and photoluminescence emissions were observed from the MoS2 monolayers under the ZnO nanorods in these coupled structures, which was attributed to the light antenna effect of the ZnO nanorods. These hybrid and incorporation protocols for layered materials will provide new perspectives and opportunities for promoting the construction of heterojunctions with adjustable layered structures leading to fascinating fundamental phenomena and advanced devices.

关键词： MoS2 monolayers ZnO nanorods Raman photoluminescence

SeBROP:blind ROP attacks without returns

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2022年第4期16卷 185-202页

作者： tianning zhang Miao Cai Diming zhang Hao Huang Department of Computer Science and Technology Nanjing UniversityNanjing210023China School of Computer and Information Hohai UniversityNanjing211106China College of Computer Engineering Jiangsu University of Science and TechnologyZhenjiang212008China

Currently,security-critical server programs are well protected by various defense techniques,such as Address Space Layout Randomization(ASLR),eXecute Only Memory(XOM),and Data Execution Prevention(DEP),against modern code-reuse attacks like Return-oriented Programming(ROP)***,in these victim programs,most syscall instructions lack the following ret instructions,which prevents attacks to stitch multiple system calls to implement advanced behaviors like launching a remote *** this kind of gadget greatly constrains the capability of code-reuse *** paper proposes a novel code-reuse attack method called Signal Enhanced Blind Return Oriented Programming(SeBROP)to address these *** SeBROP can initiate a successful exploit to server-side programs using only a stack overflow *** leveraging a side-channel that exists in the victim program,we show how to find a variety of gadgets blindly without any pre-knowledges or reading/disassembling the code ***,we propose a technique that exploits the current vulnerable signal checking mechanism to realize the execution flow control even when ret instructions are *** technique can stitch a number of system calls without returns,which is more superior to conventional ROP ***,the SeBROP attack precisely identifies many useful gadgets to constitute a Turing-complete *** attack can defeat almost all state-of-the-art defense *** SeBROP attack is compatible with both modern 64-bit and 32-bit *** validate its effectiveness,We craft three exploits of the SeBROP attack for three real-world applications,i.e.,32-bit Apache 1.3.49,32-bit ProFTPD 1.3.0,and 64-bit Nginx *** results demonstrate that the SeBROP attack can successfully spawn a remote shell on Nginx,ProFTPD,and Apache with less than 8500/4300/2100 requests,respectively.

关键词： code-reuse atack ROP signal

Epitaxial indium antimonide for multiband photodetection from IR to millimeter/terahertz wave

在线全文

学校读者我要写书评

暂无评论

Photonics Research 2022年第5期10卷 1194-1201页

作者： JINCHAO TONG HENG LUO FEI SUO tianning zhang DAWEI zhang DAO HUA zhang School of Electrical and Electronic Engineering Nanyang Technological UniversitySingapore 639798Singapore School of Physics and Electronics Central South UniversityChangsha 410083China Ministry of Education and Shanghai Key Laboratory of Modern Optical System University of Shanghai for Science and TechnologyShanghai 200093China

Conventional photodetection converts light into electrical signals only in a single electromagnetic *** detection technology is highly desirable because it can handle multispectral information discrimination,identification,and *** epitaxial solid-state multiband detection technologies are mainly within the IR wave ***,we report epitaxial indium antimonide on gallium arsenide for IR and millimeter/terahertz wave multiband *** photoresponse originates from interband transition in optoelectrical semiconductors for IR wave,and surface plasmon polaritons induced nonequilibrium electrons for a millimeter/terahertz *** detector shows a strong response for an IR wave with a cutoff wavelength of 6.85 μm and a blackbody detectivity of 1.8×10^(9) Jones at room *** a millimeter/terahertz wave,the detector demonstrates broadband detection from 0.032 THz(9.4 mm)to 0.330 THz(0.9 mm);that is,from Ka to the W and G bands,with a noise equivalent power of 1.0×10^(-13) W Hz^(-1/2) at 0.270 THz(1.1 mm)at room *** detection performance is an order of magnitude better while decreasing the temperature to 170 K,the thermoelectric cooling *** detectors,capable of large scale and low cost,are promising for advanced uncooled multiband detection and imaging systems.

关键词： millimeter multiband wave