Elemental Compositions of Over 80 Cell Phones

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.     

Zero/Positive Capacities of Two-Dimensional Runlength-Constrained Arrays

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$k_i$.     

基于51单片机的多功能电子时钟设计

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。     

Better breast cancer detection

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     

Reduction of earthquake risk in the United States: bridging the gapbetween research and practice

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     

Recent Advances in Hybridization,Doping, and Functionalization of 2D Xenes

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.     

基于TM影像光谱指数的棉花病害严重度估测

通过获取多时相试验区TM影像和大田同步调查棉花黄萎病,将TM影像光谱指数与病害严重度进行相关分析,建立棉花病害严重度估测模型.结果表明:随着病害严重度的增加,TM影像光谱指数B2,B4,SATVI,OSAVI,MSAVI,TSAVI,SVNSWI,SNSWIa,SNSWIb,SVNI,DNSIa,DNSIb,NDSWI...     

CompactPCI总线技术及系统设计

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。     

通信传输技术九十年代新动向

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。