自由电子激光的小型化研究

本文通过对自由电子激光输出波长的分析,指出了自由电子激光小型化的研究方向─-微型摆动器的研究。在分析了小周期摆动器研究现状的基础上,提出了电流摆动器。它不但具有与静磁摆动器相同的效果,而且它的周期可以任意调节。因而,它便于控制。最后,还指出了有待进一步研究的问题。     

一种基于单片机的变电站控制保护系统的实现

以单片机８０３１ 为核心组成的采集、保护和通信模块，通过ＲＳ４８５ 的连接，与４８６ 工控微机构成了分布式３５ ｋＶ 变电站的自控系统，实现变电站的计量、保护和控制等功能，以达到变电站的无人值守或少人值守。     

结构粘结剂的试验研究

粘结剂是粘钢加固技术的关键材料,通过对粘结剂的试验研究,得到了粘结剂的拉压试验曲线与材料力学指标以及粘附于各种标号混凝土时,粘结层的抗剪强度;并且还进行了粘结剂的短期流变试验。     

低电阻率气层测井评价方法

粘土矿物成份是造成气层电阻率低的主要原因。用灰色静态模型计算孔隙度，用BP神经网络计算束缚水饱和度等参数。与岩心分析结果比较，储层参数计算结果精度有所提高。用储层参数建立气层和水层的判别式，判别结果与试油有较好的一致性。综合数字处理结果建立了气层产能评价模型，处理结果与试油结果比较，符合率82％。     

修井机多桥间转向传动机构的设计

对于大型修井机采用的重型底盘,多桥转向系统是底盘开发中的关键技术之一。在分析目前修井机采用的转向传动结构(方案1)存在问题的基础上,参照军用车底盘的应用案例又提出了2种方案,经对比分析,确定了最佳的传动机构新方案,并根据多桥转向理论和四连杆机构的几何关系对该机构进行了参数确定。通过实际应用,证明该转向传动布置方案具有传动误差小、不产生附加转向、现场调节安装方便、易于组织生产等特点。     

The use of doped polyaniline as an electrode in the galvanic anodic protection of ferrous metals in industrial acid solutions

In order to investigate the galvanic anodic protection (GAP) of ferrous metals (such as 410, 304 and 316 stainless steels) in acid solutions by doped polyaniline (PANi), separate doped PANi powder-pressed electrodes with different surface areas (the area ratio of the PANi electrode to stainless steel is between 1:1 and 1:2) have been prepared. These were coupled with ferrous metal in the following solutions: 5 M sulphuric acid, 5 M phosphoric acid and industrial phosphoric acid (containing 5 M phosphoric acid and 0.05% chloride ion) to construct a galvanic cell, in which PANi is cathode while ferrous metal is anode. The results indicate that a PANi electrode with sufficient area can provide corrosion protection to stainless steel in these acidic solutions. A pilot scale coupling experiment was carried out. The results indicate that PANi is a promising material as an electrode for the anodic protection of ferrous metals in acidic solutions in industrial situations.     

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/.     

空气中^131I的取样和测量方法的研究

本文介绍一种气态和气载~(131)I 取样器。着重介绍了一种指数分布源的效率刻度方法,讨论了与取样有关的一些问题。     

微波辐射电镜生物样品制备方法研究

本文报道一种快速微波辐射电镜样品制备方法──水浴法，以及这个方法在动植物样品超薄切片制备中的应用。实验结果表明，水浴法使得样品可以接受相对较长时间的微波辐射而不致造成任何损伤，浸泡液和样品的温度控制简单而且准确，样品处理的结果内外均匀一致，超微结构保存优秀，完全可与常规制样法和Ｌｏｇｉｎ法的结果相媲美，而且在某些方面水浴法要优于常规法和Ｌｏｇｉｎ法。     

Sequence clustering strategies improve remote homology recognitions while reducing search times

Sequence databases are rapidly growing, thereby increasing thecoverage of protein sequence space, but this coverage is unevenbecause most sequencing efforts have concentrated on a smallnumber of organisms. The resulting granularity of sequence spacecreates many problems for profile-based sequence comparisonprograms. In this paper, we suggest several strategies thataddress these problems, and at the same time speed up the searchesfor homologous proteins and improve the ability of profile methodsto recognize distant homologies. One of our strategies combinesdatabase clustering, which removes highly redundant sequence,and a two-step PSI-BLAST (PDB-BLAST), which separates sequencespaces of profile composition and space of homology searching.The combination of these strategies improves distant homologyrecognitions by more than 100%, while using only 10% of theCPU time of the standard PSI-BLAST search. Another method, intermediateprofile searches, allows for the exploration of additional searchdirections that are normally dominated by large protein sub-familieswithin very diverse families. All methods are evaluated witha large fold-recognition benchmark.