共查询到20条相似文献,搜索用时 46 毫秒
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Beverley Christian Alexandre Romanov Irina Romanova Laura J. Turbini 《Journal of Electronic Materials》2014,43(11):4199-4213
Over the last few years, 85 cell phones have been disassembled, ground up, dissolved, and analyzed for elemental content, mainly for information about the metals present in the phones, but also for some metalloids and nonmetals. The following list of 38 elements were detected in some or all of the phones: Be, B, Mg, Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Y, Nb, Pd, Ag, In, Sn, Sb, Te, Ba, Ta, W, Pt, Au, Tl, Pb, Bi, Pr, Nd, Sm, Eu, Gd, Tb, Dy, and Er. Cadmium was never detected. This paper discusses the methods used for carrying out the analysis, proposes possible sources in the telephones for the elements of interest, the reasons for the interest in most of the elements, and method repeatability. 相似文献
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《IEEE transactions on information theory / Professional Technical Group on Information Theory》2005,51(9):3186-3199
A binary sequence satisfies a one-dimensional$(d_1, k_1, d_2, k_2)$ runlength constraint if every run of zeros has length at least$d_1$ and at most$k_1$ and every run of ones has length at least$d_2$ and at most$k_2$ . A two-dimensional binary array is$(d_1, k_1, d_2, k_2; d_3, k_3, d_4, k_4)$ -constrained if it satisfies the one-dimensional$(d_1, k_1, d_2, k_2)$ runlength constraint horizontally and the one-dimensional$(d_3, k_3, d_4, k_4)$ runlength constraint vertically. For given$d_1, k_1, d_2, k_2, d_3, k_3, d_4, k_4$ , the two-dimensional capacity is defined as $$displaylines C(d_1, k_1, d_2, k_2; d_3, k_3, d_4, k_4) hfillcr hfill=, lim_m,n rightarrow infty log_2 N(m, n ,vert, d_1, k_1, d_2, k_2; d_3, k_3, d_4, k_4)over mn $$ where $$N(m, n ,vert, d_1, k_1, d_2, k_2; d_3, k_3, d_4, k_4)$$ denotes the number of$m times n$ binary arrays that are$(d_1, k_1, d_2, k_2; d_3, k_3, d_4, k_4)$ -constrained. Such constrained systems may have applications in digital storage applications. We consider the question for which values of$d_i$ and$k_i$ is the capacity$C(d_1, k_1, d_2, k_2; d_3, k_3, d_4, k_4)$ positive and for which values is the capacity zero. The question is answered for many choices of the$d_i$ and the$k_i$ . 相似文献
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单片机体积小、重量轻、抗干扰能力强、环境要求不高、价格低廉、可靠性高、灵活性好、深受初学者喜欢。以STC90C58为核心控制芯片,DS1302为时钟芯片,DS18B20采集温度,完成多功能电子时钟的设计。该设计能够准确显示年、月、日、星期、时、分、秒及温度,通过按键可以调整年、月、日、星期、时、分、秒、12/24小时转换、整点提示以及闹钟,还可显示阴阳历。 相似文献
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Better breast cancer detection 总被引:2,自引:0,他引:2
《Spectrum, IEEE》2001,38(5):50-54
X-rays go digital, computers read film, and chemicals mark tumors, but will these new technologies make it in the clinic? The imaging technologies considered for breast cancer include film-screen mammography, full field digital mammography, ultrasound, magnetic resonance imaging, scintimammography, thermography, electrical impedance imaging, optical imaging, electric potential measurement, positron emission tomography, novel ultrasound techniques, elastography, magnetic resonance spectroscopy, thermoacoustic computed tomography, microwave imaging, Hall-effect imaging and magneto-mammography 相似文献
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Continuing efforts under the auspices of the National Earthquake Hazards Reduction Program are under way to improve earthquake risk assessment and risk management in earthquake-prone regions of Alaska, California, Nevada, Washington, Oregon, Arizona, Utah, Wyoming, and Idaho, the New Madrid and Wabash Valley seismic zones in the central United States, the southeastern and northeastern United States, Puerto Rico, Virgin Islands, Guam, and Hawaii. Geologists, geophysicists, seismologists, architects, engineers, urban planners, emergency managers, health care specialists, and policymakers are having to work at the margins of their disciplines to bridge the gap between research and practice and to provide a social, technical, administrative, political, legal, and economic basis for changing public policies and professional practices in communities where the earthquake risk is unacceptable 相似文献
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Lei Zhang Tian Gong Zhiqiang Yu Huan Dai Zhenjingfeng Yang Ganlin Chen Jinhua Li Ruikun Pan Huide Wang Zhinan Guo Han Zhang Xiao Fu 《Advanced functional materials》2021,31(1):2005471
The emerging monoelemental 2D materials named as Xenes including borophene, silicene, germanene, stanene, phosphorene, arsenene, antimonene, bisthumene, selenene, and tellurene, have attracted rising attention experimentally and theoretically. Because of their excellent and versatile physical, chemical, electrical, and optical advantages, Xenes have been shown or have been predicted to have excellent performance in nanotechnology applications, addressing challenges and advances in electronics, energy, healthcare, and environment. In this review, the basic fundamentals in the classification of the periodic table group and the synthesis methods for the emerging materials are summarized. Then, the hybridization, doping and functionalization of 2D Xenes, and their corresponding applications are presented. Furthermore, a summary of research progress on 2D Xenes and the challenges and perspectives for their further development are discussed. 相似文献
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CompactPCI总线技术及系统设计 总被引:1,自引:1,他引:0
CompactPCI总线具有高总线带宽、高性能、支持热插拔,满足高速度、高性能尤其是复杂控制算法并要求可视化操作的应用场合的功能需求。首先,对CompactPCI总线技术在扩展性、封装和连接、被动式背板、热插拔和高性能等方面的技术特点。然后对其核心技术——热插拔技术做了简要的介绍,并在此基础上,对CompactPCI系统设计的相关问题进行了详细的论述。最后指出CompactPCI总线技术在工业、热力、石化、冶金、交通、现代通讯、核能、航空、航天、军事等领域具有广阔的应用前景。 相似文献
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本文概述九十年代通信技术的新动向,主要讲卫星通信、移动通信、光纤通信以及公用和专用通信网传输技术的发展趋势。文中着重指出各种有前途的新技术,包括卫星通信的星上点波束天线,小孔径天线地面终端,与ISDN兼容;数字移动通信的蜂窝微区(micro-cell),个人便携通信的无线接入交换网;光纤通信的掺铒光纤放大器,DFB调谐单频激光管,多量子阱(MQW),光电子集成,外差检测,密集FDM多路载波通信;以及公用通信网数字化、综合化、宽带化组成B-ISDN,同步光纤网,同步数字体系,异步转移方式;专用通信网的局域网(LAN和MAN),光纤分布数据接口,分隙环(slotted ring),分布排队双总线等新建议。 相似文献
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Bioinspired strategies for designing hydrogels with excellent adhesive performance have drawn much attention in biomedical applications. Here, bioinspired adhesive hydrogels tackified by independent nucleobase (adenine, thymine, guanine, cytosine, and uracil) from DNA and RNA are successfully explored. The nucleobase‐tackified hydrogels exhibit an excellent adhesive behavior for not only various solid substrates (polytetrafluoroethylene, plastics, rubbers, glasses, metals, and woods) but also biological tissues consisting of heart, liver, spleen, lung, kidney, bone, and muscle. The maximum adhesion strength of A‐, T‐, G‐, C‐, and U‐tackified hydrogels on the aluminum alloy surface is 780, 166, 250, 227, and 433 N m?1, respectively, superior to that of pure PAAm hydrogels (40 N m?1) after adhesive time of 10 min. It is anticipated that bioinspired hydrogels will play a significant role in the applications of wound dressing, medical electrodes, tissue adhesives, and portable equipment. Moreover, the bioinspired nucleobase‐tackified strategy would open a novel avenue for designing the next generation of soft and adhesive materials. 相似文献
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提出一种矿井智能化监管系统设计方案,该系统包括无线传感器网络(WSN)、工业以太网络、人员定位卡、井下视频手机、监管服务器、监控计算机、数据库、中心交换机、智能化监管信息平台。系统将工业以太网络和无线传感器网络结合,构建井下有线/无线的混合通信系统进行数据传输,井上利用智能化信息监管平台实现与井下作业人员、井上管理人员、井上其他人员的数据通信和资源共享;该系统具有井下人员实时定位、井下与井上实时视频通信、矿井环境监测、智能化信息处理、矿井信息分发、资源调度、异常情况报警等功能,矿井环境监测包括对瓦斯、CO、电化学氧气、硫化氢、风速、矿压、温湿度、矿尘、噪音等环境参数的监测。 相似文献
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广播电视技术台站的安全播出工作是的个复杂的系统工程,人工巡机、巡检、抄表在安全播出、机房管理中仍具有其他技术手段不可替代的作用。本文结合技术台站的工作性质、技术特点就自行设计、制作、安装、使用巡检抄表提示系统的情况予以介绍,该系统具有较强的实用意义。 相似文献
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Lipson J. Minford W. Murphy E. Rice T. Linke R. Harvey G. 《Lightwave Technology, Journal of》1985,3(5):1159-1163
We have fabricated and evaluated the first single mode wavelength multiplexer based on a diffraction grating and strip waveguides. The waveguides were employed to minimize the physical spacing between inputs in order to maximize the ratio of channel width to channel separation. The center channel insertion losses for the six channel device were 6.4, 4.9, 6.0, 5.6, 6.8, and 7.8 dB at 1279, 1308, 1338, 1508, 1536, and 1566 nm, respectively. The 1-dB full channel widths averaged 6.0 nm. A matching demultiplexer with multi-mode outputs was also fabricated. The center channel insertion losses were 0.9, 1.1, 1.2, 1.7, 1.8, and 2.1 dB at 1278, 1310, 1337, 1505, 1533, and 1563 nm, respectively. Full 1-dB channel widths ranged from 15 to 11 nm. Out of band rejection exceeded 35 dB. 相似文献
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Chandrakasan A.P. Burstein A. Brodersen R.W. 《Solid-State Circuits, IEEE Journal of》1994,29(12):1415-1428
This paper presents the design of a low-power chipset for a portable multimedia terminal that supports pen input, speech I/O, text/graphics output, and one-way full-motion video. Its power consumption was minimized using an approach that involves optimization at all levels of the design, including extended voltage scaling, reduced swing logic, and switched capacitance reduction through operation reduction, choice of number representation, exploitation of signal correlations, self-timing to eliminate glitching, logic design, circuit design, and physical design. The entire chipset, which performs protocol conversion, synchronization, error correction, packetization, buffering, video decompression, and D/A conversion, is implemented in 1.2 μm CMOS and operates from a 1.1 V supply while consuming less than 5 mW 相似文献
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Black phosphorus nanostructures (nano‐BPs) include BP nanosheets, BP quantum dots, and BP nanoparticles. Since first being discovered in 2014, nano‐BP has become one of the most popular nanomaterials. Nano‐BP has many unique properties, such as excellent surface activity, tunable bandgap, high carrier mobility, moderate on/off ratio, excellent biocompatibility, good biodegradation, etc., all of which make nano‐BP particularly attractive in biomedicine and biosensing. This review article comprehensively summarizes recent advances in synthesis, functionalization, biomedicine, and biosensing applications of nano‐BP. Different methods are first introduced, such as mechanical cleavage, liquid‐phase ultrasonic exfoliation, electrochemical exfoliation, solvothermal treatment, and acoustic‐microfluidic stripping, for making the nano‐BP. Then two strategies are emphasized to enhance ambient stability of nano‐BP, namely physical encapsulation and chemical modification. Next, how to develop nano‐BP as advanced imaging agents, nanocarriers, and nanomedicine for bioimaging (fluorescence imaging, thermal imaging, and photoacoustic imaging) and disease treatment (phototherapy and photo/chemical/immune synergistic therapy) is demonstrated. The biosensing applications on nano‐BP is introduced, including electrochemical biosensor, fluorescence biosensor, chemiluminescence biosensor, electrogenerated chemiluminescence biosensor, and colorimetric biosensor. Finally, the current challenges and future perspectives on nano‐BP in bioapplications are discussed. 相似文献