口腔数字全景X射线摄影系统检测方法

本文根据口腔数字全景X射线摄影系统的技术特性,在实验数据基础上分析、研究,确定检测参数和技术指标,制定出口腔数字全景X射线摄影系统检测方法,为计量系统及医院质量控制,提供检测技术依据。     

口腔全景X射线辐射源关键计量特性的检测方法研究

<正>近几年,口腔全景X射线辐射源广泛应用于各级医院,已成为口腔放射诊断的主要设备。然而,国内还没有相应的计量检定规程,这就给医院的设备管理和质量控制带来难度。本文在参考普通X射线辐射源检定方法的基础上,对原有标准器进行改进,研究出一套适合于口腔全景X射线辐射源计量检测的方法。     

全景影像后期工作流程及技术方案介绍

正近年来,随着虚拟现实技术的兴起,其中一个重要的分支"全景"影像也随之成为热点。同时,"全景"影像的拍摄,由于高清摄影机小型化程度的提高而变得越来越经济方便。从去年到今年的一年间,各类全景摄影机也不断在全景设备市场涌现。如图1中来自Nokia的OZO、三星的ProjectBeyond、GoPro的Omni,还有Google的Jump都是现在市场上热卖的全景摄影机或全景摄影架。     

分析口腔X射线机影像质控检测

目的:分析口腔X射线机影像质量控制检测结果,并制定相应的加强质量控制措施,使其更好地服务于口腔X射线放射科诊断工作。方法:选取某市医院2013年-2014年已检的120台医用口腔X射线机,依据国家相关技术规定、检测方法和防护指标及使用多功能剂量仪对设备进行检测,评价其检测结果。结果:120台医用口腔X射线机来源以口腔科室为主,其中占据数量较多的是图像采集,综合性医院和少数高档医院口腔诊所主要集中进口机器。经检测结果得知,医院口腔科、放射科及口腔诊所的设备合格率为90%以上,进口设备的合格率为100%,全景机的合格率低于牙片机。根据牙科X射线摄影最短焦皮距、X射线加载时间值的偏差、有用线束半值层等性能指标检测结果合格率均有不同。结论:医院应及时针对影响口腔X射线机性能质量问题采取措施,使X射线机影像质量技术参数达到最佳状态,降低受检者照射剂量和漏诊率及废片率,提高口腔医疗诊断准确率。     

全景牙科X射线机校准研究

为解决全景牙科X射线机量值溯源问题,该文通过检测不同厂家不同型号的全景牙科X射线机的性能,确定全景牙科X射线机校准的计量参数:空气比释动能、辐射输出的重复性、辐射质、管电压、空间分辨率、低对比度分辨率以及曝光时间。根据全景牙科机的工作原理,研制用于检测校准全景牙科X射线机的设备,并采用该设备,开展全景牙科X射线机的管电压、分辨力、辐射输出的辐射质检测以及重复性试验。在实验测量结果的基础上,给出全景牙科X射线机的校准方法。     

天津牌荧光缩影医用X射线胶片

天津牌荧光缩影医用X射线胶片是一种正色性、高感光度，中等反差，细颗粒，单面涂布感光层的胶片，专门适用于拍摄X射线间接摄影机荧光屏上的图像，其生产过程采用一系列先进而精密复杂的工艺技术，如：计算机控制双注法乳化，特殊晶型卤化银颗粒，新型化学增感技术，高速光学增感剂，新型坚膜剂等，因此其质量可与一些世界名牌产品媲美。     

5000 m3球罐γ射线全景曝光探伤

介绍了 5 0 0 0m3球罐γ射线全景曝光探伤的线源选择 ,γ射线探伤微电脑自动控制仪、输源管与驱动钢丝软轴及其它配套仪器设备的选购 ,γ射线全景曝光探伤工艺要求及注意事项。     

医用口腔数字化曲面断层X射线设备空气比释动能测量值的不确定度评定

医用口腔数字化曲面断层X射线设备空气比释动能测量值的不确定度的评定方法。     

JJG744-2004中存在的问题

JJG744-2004《医用诊断X射线辐射源》检定规程在某些条款及检定方法上较JJG744-1997的确有所改进,但笔者认为基于以下原因还应作进一步修订:1.对X射线机分类描述不清,JJG744-2004中将X射线机分为连续工作方式、间歇工作方式、有影像增强器和无影像增强器。笔者认为应细分为摄影机和透视机,并分别描述检定项目、方法及结果判定。2.JJG744-2004未提到普通荧光屏透视机分辨力的测量要求和方法,但是普通荧光屏透视机只依据空     

超高解像力数字摄影机

我们正开发一种摄影机,它是一种基于利用CCD列阵压电微调节产生3000×2320像素的Kontron ProgRes 3012摄影机。这种新摄影机可记录大至1平方米美术绘画,解像力达每毫米20像素。这种新型摄影机可结合X—Y转移阶段,在此阶段,可使列阵环绕像平面移动以获得可镶嵌的组块,形成最终大数字式影像。     

Polymers for Mucoadhesive Drug Delivery System: A Current Status

To overcome the relatively short gastrointestinal (GI) time and improve localization for oral controlled or sustained release drug delivery systems, bioadhesive polymers that adhere to the mucin/epithelial surface are effective and lead to significant improvement in oral drug delivery. Improvements are also expected for other mucus-covered sites of drug administration. Bioadhesive polymers find application in the eye, nose, and vaginal cavity as well as in the GI tract, including the buccal cavity and rectum. This article lays emphasis mainly on mucoadhesive polymers, their properties, and their applications in buccal, ocular, nasal, and vaginal drug delivery systems with its evaluation methods.     

Operation and investigation of a tilted bottom cavity for pyrgeometer characterizations

A new cavity for pyrgeometer characterizations has been built at the Infrared Radiometry Section of the World Radiation Center (WRC-IRS) at PMOD/WRC. The calculated effective emissivity of 0.99993+/-0.00033 was obtained from Monte Carlo simulations taking into account the geometry and the measured temperature distributions of the cavity. The cavity is operated in a temperature range of -30 degrees C to +30 degrees C and is initially flushed with nitrogen to reduce the relative humidity in the cavity. The estimated uncertainties of retrieved pyrgeometer parameters k1, k2, and k3 are +/-0.024, +/-0.0008, and +/-0.03, respectively. The relative uncertainty of pyrgeometer sensitivity C is 0.8%. The comparison with the cavity used since 1995 at PMOD/WRC gave average differences of 0.005, 0.00026, and 0.08 for k1, k2, and k3, respectively. The pyrgeometer sensitivity retrieved with the new cavity is on average 1.0% higher than with the original cavity.     

Polymers for mucoadhesive drug delivery system: a current status

To overcome the relatively short gastrointestinal (GI) time and improve localization for oral controlled or sustained release drug delivery systems, bioadhesive polymers that adhere to the mucin/epithelial surface are effective and lead to significant improvement in oral drug delivery. Improvements are also expected for other mucus-covered sites of drug administration. Bioadhesive polymers find application in the eye, nose, and vaginal cavity as well as in the GI tract, including the buccal cavity and rectum. This article lays emphasis mainly on mucoadhesive polymers, their properties, and their applications in buccal, ocular, nasal, and vaginal drug delivery systems with its evaluation methods.     

铝纤维板共振结构声学特性的理论初析

铝纤维板与背后空腔组成的吸声结构具有明显的共振吸声特性。铝纤维板的声学参量,即相对声阻抗率ζ和等效厚度l与等效参孔率σ的比值,可由驻波管法测量的吸声系数频响曲线反演求得。南于铝纤维毡的材质均摊性,铝纤维板共振吸声结构不再可以看成“局部反应”的声学元件,在空腔内加置小间距的横隔板有助于提高结构的吸声性能。     

高碳钢冷轧辊拔长过程内 部孔洞演变模拟分析

目的研究拔长锻造过程中,不同的工艺参数对锻件内部孔洞闭合效果的影响。方法采用数值模拟的方法,研究了高碳钢冷轧辊拔锻坯在拔长锻造过程中,下砧宽、压下量、送进量等关键工艺参数对锻坯内部孔洞闭合效果及应力应变分布状态的影响。结果 3个工艺参数都对锻件心部质量及内部应力应变状态有影响。结论有效压实心部疏松缺陷的最佳砧宽为200 mm;采用每次压下量基本一致的工艺方案,即每次压下率保持在17%左右,可保证锻件变形均匀,从而获得较好的心部质量;相对送进量为0.8时,有利于心部孔洞的锻合。     

Measurement of magnetic losses in resonant metallised ferrites

Microwave magnetic losses, far enough from the ferromagnetic resonance, are generally measured by perturbation methods, i.e. by comparing resonance of a cavity with and without magnetic sample. Nevertheless such methods require very accurate apparatuses, for parameters of the resonant cavity are slightly altered by the presence of the sample because of the relative smallness of the latter. The fore-going difficulty can be overcome by using the sample as a resonant cavity. The TM010mode of a cylindrical metallised sample are very convenient to achieve accurate measurement of magnetic losses. This method is quite effectual for materials with low magnetic moments and for low frequencies (from 1 to 5 GHz). Large metallic cavities are avoided and the apparatus is very simple.     

Investigation of a Flow around Cavities

A supersonic flow around a ring cavity on a cylindrical body has been experimentally investigated in wide ranges of relative lengths of the cavity and Mach numbers. The influence of these parameters on the pressure distribution, the structure of the flow, and the regimes of flow around the cavity has been determined.     

分数导数黏弹性准饱和土中球空腔振动特性

在频率域内用解析方法研究分析了简谐轴对称荷载和流体压力作用下分数导数黏弹性准饱和中球空腔的稳态响应问题。将土骨架等效为具有分数阶导数本构关系的黏弹性体,基于Biot两相饱和介质模型,通过势函数推导求得了边界部分透水时分数导数粘弹性准饱和土中球空腔的位移、应力和孔压等的解析解。根据界面连续性条件,确定了待定系数的表达式。在此基础上,考察了准饱和土各参数对动力响应的影响,结果表明：轴对称荷载和流体压力两种情况时,相对渗透系数对动力响应的影响有较大的差异。分数导数本构模型更合理地描述了准饱和土中球空腔的振动特性。     

Methods of Measuring the Thermodynamic Temperature of a High-Temperature Blackbody

A brief comparative analysis is made of methods of measuring the temperature of the radiating cavity of a high-temperature blackbody. The methods examined are based on relative and absolute measurements of the radiation parameters and the use of blackbodies during phase transformations.     

Photoshop的新特色功能介绍之一——全景接片自动合成

这是新版PhotoshopCS的一项新的特色功能,适用于把分别的画面连接起来,合成一幅全景画面,影像质量很好,操作程序简便、快速而实用,本文以实际例子和图像详细阐述其具体操作过程。