In situ radiation measurement and estimation of U/Th ratio to reflect on the uranium bearing potential zone in metamorphic rocks of Mahendragarh district, Haryana

Gross gamma radiation survey was carried out using Nal(Tl) scintillator based portable gamma ray spectrometer (PGRS) around areas of Gaonri, Dholera, Pachnota and Meghot in Mahendragarh district, Haryana. Geologically the area forms part of north Delhi fold belt comprising calc-silicate, quartz biotite schist, impure marble, quartzite and pegmatite rocks. Equivalent uranium (eU₃O₈) concentration in ppm was estimated in situ on a regular grid pattern of 500 m (E-W) × 1000 m (N-S) and grab samples were collected at grid locations for analyzing in the laboratory for estimating the contents of eU₃O_s Ra_eq, ThO₂ and %K. A comparison with the laboratory analysed grab samples for eU₃0₈ data and in situ radiation measurements shows a good match of the two sets of data. The in situ measurements indicate higher concentration of eU₃O₈ in Chapra Bibipur in northeastern most corners, Maghot area in central part, Gaonri in western part and Pachnota in southwestern part of the study area. As index to uranium favorability, U(Ra_eq)-Th contour map (prepared using Surfer software with Krieging interpolation method for this grid size) based on the data on grab samples was generated which show three major clusters of relatively high U-Th ratio. The blocks delineated are enriched in sodic mineral albite which support albite hosted uranium mineralization potential in metamorphic rocks in Haryana.      

紫外线辐照光强对HDPE化学结构及对HDPE/PC共混体系增容效应的影响

采用FT-IR,XPS,凝胶分析以及熔融指数、接触角和力学性能测定,研究了不 同紫外辐照光强对高密度聚乙烯（HDPE）的化学结构、流动性、亲水性和辐照改性 HDPE在HDPE/聚碳酸酯（PC）共混体系中的增容效应的影响。在相同辐照时间下, 随紫外光强提高,引入HDPE分子链的含氧基团数量增加;在辐照过程中,紫外光强 对HDPE的交联有显著影响,在较低光强（32W/m~2）下辐照24h的HDPE无凝胶生成, 便在较高光强（45和78W/m~2）下辐照24h后,HDPE产生凝胶,其含量随紫外光强提 高而增多;与未辐照HDPE相比,较高光强下辐照HDPE的熔融指数有所下降,但其亲 水性得到明显改善;紫外辐照改性HDPE对HDPE/PC体系有增容作用,随紫外光强提 高其增容效应明显增强。与未增容HDPE/PC（80/20）体系相比,加入20%辐照 24hHDPE（光强78W/m~2）的HDPE/PC共混物的拉伸屈服强度从26.3MPa提高到30. 2MPa,缺口冲击强度从51J/m提高到158J/m。     

全光纤通信系统中的偏振激光器

报道了一种简单、实用的解决全光通信中的光源偏振问题的方法,并通过实验对偏振环形腔光纤激光器与没有偏振措施的普通环形腔激光器进行了比较,观察到了清晰的眼图.     

Effect of radiation on conductivity of solid PVA–KOH–PC composite polymer electrolytes

The aim of this work is to enhance the room temperature conductivity of solid alkaline composite polymer electrolytes (ACPEs) based on polyvinyl alcohol/potassium hydroxide/propylene carbonate (PVA–KOH–PC) composites by cross-linking the PVA and bond scission of the PC by γ-radiation. The ACPEs were prepared by solvent-casting technique and irradiated with doses up to 200 kGy at room temperature. The microstructure of the ACPEs was measured using XRD spectrometer, and the results show the structural change from semicrystalline to amorphous, indicating that the cross-linking has been achieved at higher doses. It was found that the PKOH composite at 40 wt% KOH and PPC composite at 60 wt% PC show higher conductivities. The conductivity of the PKPC composites is dominated by dc conductivity at higher frequencies and that PC with 60 wt% has the highest conductivity at a dose of 200 kGy.Paper presented at the International Conference on Functional Materials and Devices 2005, Kuala Lumpur, Malaysia, June 6–8, 2005.     

ESR数据系统的研制

报道了电子自旋磁共振谱仪与IBM PC微型机联用,建立了所需要的硬件系统,包括接口和放大器,研制了分辨率为12位的AD/DA转换器,达到同步采样控制,并实现了X-Y记录仪,示波器,绘图仪与打印机的输出,同时系统软件配有信号采样、信号累加、信号平滑、谱线加减、测量g因子及A值,ESR谱的一、二次积分等一系列数据处理程序,还具有谱线模拟、线形分析等一些应用软件,对于谱的定量和解析极为方便,大大提高了谱仪的功能.     

An automatic multistep method for solving stiff initial value problems

A multistep method with matricial coefficients is developed. It can be used to solve stiff initial value problems of the form y′ = Ay + g(x, y). This method bears the nature of the classical Adams—Bashforth—Moulton PC formula and can be shown to be consistent, convergent and A-stable. A careful reformulation of this method legitimatizes the implementation of this algorithm in a variable-step variable-order fashion. Numerical test results from a PECE mode of this method show its possible advantages.     

Widely tunable Yb-doped laser with all fiber structure

In this paper, an all fiber Yb³⁺-doped fiber ring laser with large tuning range has been reported. A 976 nm laser diode (LD) pumped laser is used as the pump source and high concentration Yb³⁺-doped fiber is adopted as gain medium. Adjusting the polarization controller (PC), a widely tunable range of 20 nm from 1030 to 1050 nm is obtained. The spectral linewidth of the pulse is less than 0.2 nm. Comparing with other fiber laser structures, the fiber laser with an all-fiber structure has higher efficiency and better stability. The laser also has very stable and flat output within the whole tuning range.     

基于STM32的汽车涂装线监控系统研究与实现

针对现有汽车电泳涂装线监控系统普遍存在信息采集不全面、分析处理时间长、共享程度低等问题,研究开发了基于STM32的涂装线设备状态监控系统。该系统采用高性能的STM32处理器,结合通用性好易开发的VC 6.0平台自主开发系统上位机软件,完成对设备数据的采集、处理分析及在线显示。首先,构建基于数据采集、中央处理、设备控制及通信的下位机硬件系统;然后,通过RS485总线技术实现各采集模块与中央处理模块的通讯,并通过串口及时将设备参数上传到上位机,实现涂装线设备的实时监控。     

聚碳酸酯在亚临界水中解聚的研究

采用间歇式高压反应装置研究聚碳酸酯(PC)在亚临界水中的解聚.在温度260～340℃、压力4.8～14.8 MPa、反应时间5～60min的反应条件下,考察了反应温度及反应时间对PC解聚率及主产物双酚A(BPA)和苯酚(PhOH)回收率的影响.产物分别采用傅里叶红外光谱(FTIR)、扫描电子显微镜(SEM)、气质联谱(...     

Chemical modification of polymeric microchip devices

Analytical polymeric microchips in both fluidic and array formats offer short analysis times, coupling of many sample processing and chemical reaction steps on one platform with minimal sample and reagent consumption, as well as low cost, minimal fabrication times and disposability. However, the invariable bulk properties of most commercial polymers have driven researchers to develop new modification strategies. This article critically reviews the scope and development of chemical modifications of such polymeric chips since 2003. Surface modifications were based on chemical derivatization or activation of surface layers with reagent solutions, reactive gases and irradiation. Bulk modification of polymer chips used newly incorporation of monomers with selective chemical functionalities throughout the bulk polymer material and integrated the chip modification and fabrication into a single step. Such modifications hold a great promise for establishing a true ‘lab-on-chip’ as can be seen from many novel applications for modulating electroosmosis, suppressing protein adsorption in microchip capillary electrophoretic separations, extraction of analytes and for zone-specific binding of enzymes and other biomolecules.