Low-temperature growth of silicon-boron layer as solid diffusionsource for polysilicon contacted p+-n shallow junction

A new material, Si-B, is proposed as a solid diffusion source for fabrication of poly-Si contacted p⁺-n shallow junctions. The junction depth of the Si-B source diode has been measured and compared with that of a BF₂⁺-implanted poly-Si source diode. It was found that the Si-B source diode had a much shallower junction and was less sensitive to thermal budget than the BF₂⁺ source diode. This was attributed to the smaller surface concentration and diffusivity of boron in the silicon in Si-B source diodes. Regarding electrical characteristics of diodes with a junction depth over 500 Å, a forward ideality factor of better than 1.01 over 8 decades and a reverse-current density lower than 0.5 nA/cm² at -5 V were obtained. As the junction depth shrank to 300 Å, the ideality factor and reverse current density of diodes increased slightly to 1.05 and 1.16 nA/cm², respectively. These results demonstrated that a uniform ultrashallow p⁺-n junction can be obtained by using a thin Si-B layer as a diffusion source     

MIKEII 软件系统在穆棱河流域面源污染估算中的应用

穆棱河流域面源污染入河量调查和估算采用了MIKEII软件系统，根据水质、水量实测数据，在参数率定和模型验证的基础上．对穆棱河部分河段的水质进行模拟，拟合出面源入河量和年内分布。经验证计算结果较其他方法更合理可靠。     

施工项目管理与成本控制

工程项目的施工管理与项目成本管理它是包含与被包含的关系,也是依赖与被依赖的关系。在工程项目施工中,施工项目管理它包含了诸如规划、组织、协调、实施、控制、修偏、改进等环节,而成本控制是实施、控制的项目管理中的很重要的也是项目管理成败的关键环节,故在工程项目管理中,做好施工过程中的各个分部分项工序的成本分解分析控制尤为重要,为此,工程管理人员将“项目成本控制”作为施工项目管理中的重中之重进行控制,以提高施工的最大经济效益。     

An automatic method for controlling the centre of gravity of a model

In many applications the location of the centre of gravity of a mechanical part is an important factor that a designer must consider. If it is not in a desired location, a part might not work properly, e.g. unbalanced force might be generated in a rotational part. After a part is modeled, its centre of gravity cannot be altered unless its external shape or internal mass distribution is changed. However, the external shape is usually constrained by other design considerations. In this paper, an algorithm is proposed for controlling the centre of gravity of a hollowed part. Using this algorithm, the location of the centre of gravity of a part is controlled by changing its internal mass distribution.     

A transmit/receive IF chip set for WCDMA mobiles in 0.35 /spl mu/m CMOS

An implementation of the IF section of WCDMA mobile transceivers with a set of two chips fabricated in an inexpensive 0.35-/spl mu/m two-poly three-metal CMOS process is presented. The transmit/receive chip set integrates quadrature modulators and demodulators, wide dynamic range automatic gain control (AGC) amplifiers, with linear-in-decibel gain control, and associated circuitry. This paper describes the problems encountered and the solutions envisaged to meet stringent specifications, with process and temperature variations, thus overcoming the limitations of CMOS devices, while operating at frequencies in the range of 100 MHz-1 GHz. Detailed measurement results corroborating successful application of the new techniques are reported. A receive AGC dynamic range of 73 dB with linearity error of less than /spl plusmn/2 dB and spread of less than 5 dB for a temperature range of -30/spl deg/C to +85/spl deg/C in the gain control characteristic has been measured. The modulator measurement shows a carrier suppression of 35 dB and sideband/third harmonic suppression of over 46 dB. The core die area of each chip is 1.5 mm/sup 2/.     

应用管网式水力喷射泵延长垦西油田油井免修期

水力喷射泵采油是 2 0世纪 90年代初研制成功的一种采油新工艺 ,1994年通过ISO90 0 1质量体系认证 ,主要适用于稠油井、出砂严重及偏磨、腐蚀严重的油井。 1998年 3月开始在垦西油田K71断块实施该工艺 ,目前有管网式水力喷射泵井 2 7口 ,与常规机械采油相比 ,垦西油田油井免修期由 110d延长到 35 0d左右。介绍了管网式水利喷射泵采油工艺及其在垦西油田的实施效果。     

机电一体化技术在综合采煤设备中的应用与发展

介绍了机电一体化技术在国内外煤矿井下综采设备中的应用，并论述了机电一体化技术发展与相关技术的研究。     

空间桁架结构拓扑优化设计的线性规划方法

本文以杆件内力为设计变量,构造了多工况作用下空间桁架结构拓扑优化的线性规划模型,考虑了应力和位移约束,能够避免奇异最优拓扑和不稳定结构的产生。