The investigation of 32P wire for catheter-based endovascular irradiation

The dose distribution from a 32P source has been measured and calculated in order to evaluate its application in endovascular irradiation. The source dimension was 27 mm in length and 0.3 mm in diameter and was embedded in the end of a Ni-Ti wire. Dose measurements were performed using radiochromic film in several specially designed tissue equivalent phantoms. Loevinger's point dose kernel was used for the calculation. The approximate dose rate at a radial distance of 1.5 mm from the center of the source was found to be 6.75 cGy/s per GBq (0.25 cGy/s per mCi), which allows the delivery of a therapeutic dose in a short time interval with a satisfactory homogeneity without stepping the source. However, the dose rate falls off almost exponentially along the radial distance. Therefore it may not be suitable for treating large diameter vessel from a centrally located source. The effect of a curved 32P wire source on the radial dose distribution was also investigated. The results showed that for a maximum bend of 180 degrees the dose rate was increased by as much as 20% along the inner radial distance but decreased by as much as 20% along the outer radial distance compared to the dose along a straight wire. However, for curvatures normally encountered in a clinical situation, the dose rate was changed less than 5%.     

硅中硼离子注入校准样品的研制

本文主要介绍了硅中硼离子注入校准样品的制备与研究。分别用三台SIMS仪器对样品进行了深度剖析与比对,并对用作校准目的的样品主要参数进行了定值。     

沸石催化剂在甲苯甲基化中的择形催化形用

综述了影响甲苯甲基化择形催化的因素,讨论了沸石的内外表面酸中心及酸强度、沸石的孔道、反应物和产物的吸附等因素对提高对二甲苯选择性的影响。     

航空齿轮表面硬化层断裂性能研究

按照航空齿轮的具体工艺过程，对材料12Cr2Ni4A的拉伸试样和断裂试样进行设计和加工，通过三点弯曲实验，重点研究了齿轮材料硬化层的硬度分布，硬化试样拉伸力学性能参数和断裂性能参数，实验结果表明，所采用试样的加工工艺方案是可行的，所获得的Kc基本反映我国航空硬化齿轮材料的断裂性能特征，为定量预测航空硬化齿轮疲劳寿命提供实验和理论分析的依据。     

Study on Oxygen-Sensing Properties of LaNiO3 Thin Films

The synthesis of rare-earth perovskite-type composition thin films of LaNiO₃ by means of the inorganic-sol-gel (ISG) method was studied. The structural stability under high temperature in reducing atmospheres and the oxygen-sensitivity mechanism of the LaNiO₃ thin films were examined. It is shown that under the experimental conditions, LaNiO₃ decomposes and the valance states of nickel are +2 and +3.     

Influence of Lanthanum on Fluorescence Properties of Ag-BaO Thin Films

Ag-BaO thin films doped with lanthanum were prepared by vacuum deposition. Compared with the normal Ag-BaO thin film, there is almost no change with the shape and the peak site of the fluorescence spectrum; however, fluores-cence emission strength of the whole observation band(325 -600 nm)increases about 40%, and the increase of short wavelength range is more remarkable than that of long wavelength range, which we named “blue-stronger“ phenomenon. Analytic results show that, with the forming of intermetallic compounds between silver and lanthanum, the 4f-state energy levels lie just below the Fermi level within 5 eV. It is the energy exchange between the 4f energy levels and the conduction band that causes the increase effect of fluorescence emission, and it is the optical absorption cross section of 4f electron, which increases with the increase of energy of incidence photon, that gives rise to the “blue-stronger“ phenomenon.     

2,6-二甲基萘生产技术进展

概述了国外2，6-二甲基萘生产技术现状，详细介绍了ExxonMobil公司2，6-二甲基萘的工艺路线和日本神户制钢所的提纯方法，指出了实现我国2，6-二甲基萘工业化生产应注意的问题。     

以市场需求为导向 加强校企合作办学

能否适应市场需求、得到社会认可是衡量高等技术应用型人才的唯一标准。本文提出要确立以市场需求为导向的人才培养观念,适应行业和地方经济的发展需要进行高职高专院校的专业建设和课程改革,并加强校企合作,突出校外实习在高职高专人才培养中的重要地位。     

前景璀璨的新型生物降解塑料-聚乳酸

简要介绍了聚乳酸的一般合成方法、性质、应用，着重介绍聚乳酸在医药和医疗领域中的应用和世界范围内的市场发展概况。     

用数采器对空压机进行状态监测预报

通过几个典型事例的分析、判断和处理，介绍了该厂怎样利用９１ｌ型数采器对２Ｄ１２—１００／８型空压机运行状态进行监测，以预报早期故障，为设备检修提供指导．