用αβ谱仪测量人工αβ放射性气溶胶体积活度的试验研究

本文介绍了用αβ谱仪系统同时测量αβ谱、实现Ｒｎ／Ｔｈ子体补偿、确定超铀α核素气溶胶体积活度及人工放射性气溶胶总β体积活度的技术途径。利用ＲａＡ、ＲａＣ′ａ峰的二段时间计数可确定空气中ＲａＡ、ＲａＢ、ＲａＣ的气溶胶体积活度，相应的，也能给出ＲａＢ、ＲａＣ对总β计数的贡献。根据一般环境条件下的平衡比，用ＴｈＣ′的。计数修正Ｔｈ子体对αβ测量的影响。￣［２３９］ｐｕ或／和￣［２４１］Ａｍ人工核素的α计数，可通过两段时间分别扣除ＲａＡ、ＲａＣ′拖尾的方法确定；β计数分别扣除Ｒｎ／Ｔｈ子体β贡献即可确定。在本文规定的测量条件下，对室内天然Ｒｎ子体水平在１５Ｂｑ／ｍ￣３以下，超铀α核素气溶胶体积活度的测量下限可达到０．１Ｂｑ／ｍ￣３；即使在７５Ｂｑ／ｍ￣３环境下，人工核素总β的测量下限也可达ｌＢｑ／ｍ￣３以下。     

某厂锆（Zr）生产流程中不同产物的天然放射性核素含量测定

本文报道了某厂锆(Zr)生产流程中原料(锆英砂,主要成份为 ZrSiO_4)、半成品(ZrC,ZrCl_4)、废渣和成品锆中天然放射性核素~(238)U、~(226)Ra、~(232)Th 和~(40)K 含量测定结果。采用 NaI(Tl)γ能谱法进行测定,结果表明,原料、半成品和废渣中都含有一定的放射性,各生产环节应采取适当的防护措施;成品锆中基本不含放射性,可安全地应用于各个生产和生活领域。     

Electron microscopic observations and DNA chain fragmentation studies on apoptosis in bone tumor cells induced by ~(153)Sm-EDTMP

ＥｌｅｃｔｒｏｎｍｉｃｒｏｓｃｏｐｉｃｏｂｓｅｒｖａｔｉｏｎｓａｎｄＤＮＡｃｈａｉｎｆｒａｇｍｅｎｔａｔｉｏｎｓｔｕｄｉｅｓｏｎａｐｏｐｔｏｓｉｓｉｎｂｏｎｅｔｕｍｏｒｃｅｌｓｉｎｄｕｃｅｄｂｙ１５３ＳｍＥＤＴＭＰＺｈｕＳｈｏｕＰｅｎｇ，Ｘｉａ...     

Synthesis,Functionalization, and Bioconjugation of Monodisperse,Silica‐Coated Gold Nanoparticles: Robust Bioprobes

Herein, we report an efficient process for preparing monodisperse Au@SiO₂ nanoparticles using homogeneous shaking and without the use of surface‐coupling silane agents or large stabilizers. The resulting pure‐silica surface of the Au@SiO₂ nanoparticles is very important for straightforward surface functionalization with different functional groups via well‐established silica surface chemistry. Subsequent covalent bioconjugation of the aldehyde‐functionalized Au@SiO₂ nanoparticles with various biomolecules is successfully employed to make robust nanoprobes for fast, colorimetric DNA and protein detection based on the sequence‐specific hybridization properties of DNA and the specific binding affinity between proteins, respectively.     

基于EXTEND的排队规则仿真研究

排队系统是一种典型的离散事件动态系统,在不同的排队规则下会有不同的系统特性。通过仿真软件EXTEND对不同排队规则下的排队系统进行了建模及仿真。在分析仿真结果的基础上,探讨了不同排队规则下排队系统的内在规律。     

Diagnosis and treatment of iatrogenic ureteral injury

Diagnosis and treatment of 17 patients who sustained 20 iatrogenic ureteral injuries were analyzed. Primary operations in which ureteral injury occurred are almost gynecologic procedures and general surgery. Injuries were managed by ureteroureterostomy in four, ureteral stent in one, removal suture ligation and ureteral double J-catheter in one, ureteroneocystostomy in ten, psoas-hitch technique and ureteroneocystostomy in one, nephrectomy in two. All patients with appropriate repair were followed-up periods of three to five years. Renal function of these patients had optimal results. When ureteral injury occurs, B-US, IVU, cystoscopy, retrograde ureterography or infusion of dye may be useful. An appropriate repair should be chosen according to length and position of ureteral injuries. Reoperation was optimal in two to three weeks. Immediate recognition of accidental ureteral injury provides optimal results. Patients with unrecognized injuries had suboptimal results.     

Ohmic contact and transport properties of II–VI Green/Blue laser diodes

The employment of the Zn(Se,Te) pseudo-graded contacting scheme to p-type ZnSe-based alloys contributes directly to the recent demonstration of room temperature continuous-wave operation of II– VI green-blue laser diodes. Contact ohmicity is maintained down to cryogenic temperatures which enabled the investigation of electrical transport properties associated with the p-type nitrogen-doped ZnSe, Zn(S,Se), and (Zn,Mg)(S,Se). The observation of both persistent photoconductivity and a metastable population of holes which are in thermodynamic equilibrium with hydrogenic acceptors having reduced activation energy suggests the presence of a DX-like behavior for holes in p-type (Zn,Mg)(S,Se).     

编程绘制数学曲线的探讨

通过编写程序输出数学曲线,具有一定的趣味性,可以开阔编程视野。只要具有初级程序设计能力,再结合有关数学知识就能实现。程序设计的思想是利用数学公式求得多个位置值,用Tab函数定位,用Print语句在这些位置上分别输出符号“”,从而得到由多个“”组成的数学曲线,例如三角函数曲线、抛物线曲线、半圆曲线及概率曲线等。     

项目实训中的协同编程方法研究

在高职院校的软件项目实训环节中,大多项目需要团体协作进行编程。针对如果有效提高学生的协同编程效率、团队合作意识以及合作学习能力的问题,提出了基于Dillenbourg原则的协同编程方法。通过实践证明,该方法取得了良好的实训效果。     

浅谈混凝土重力坝上游止水铜片断裂修复技术

以月潭水库上游面止水铜片修复为例,具体介绍了混凝土重力坝止水铜片缺陷产生的原因、修复方案、质量控制等,修复后达到了良好的效果,其方案可行,质量可靠,可以为其他类似工程提供借鉴。