人上尿路病变腔内微探头导管超声与X线静脉尿路造影的比较研究

目的比较腔内微探头导管超声与X线静脉尿路造影对人上尿路病变的诊断价值.方法导管超声及X线静脉尿路造影(IVP)检查30例病人.所有病例均经手术证实或其他检查方法验证.结果导管超声对肾盂内肿瘤的显示率为92%(12例/13例),IVP的显示率为54%(7例/13例);大小<10mm的肾盂内肿瘤的显示率导管超声为100%(6例/6例),IVP只有17%(1例/6例);导管超声能够准确定位肾盂旁肿瘤,显示肾盂旁血管畸形,明确输尿管梗阻病因,而IVP诊断较困难.结论IVP可作为上尿路病变的筛选性检查手段,腔内导管超声可作为后续性精细检查方法以进一步明确病变的部位、层次及性质.     

B超的声束切片厚度参数及标准化检测技术

<正>作为医学诊断设备,临床上对B超有两个最重要的技术要求:一是探测深度;二是图像分辨力。图像分辨力包括空间分辨力和对比度分辨力,其中空间分辨力又分为轴向、侧向和俯仰方向3种,而"俯仰分辨力"的更常用称谓是"切片厚度"。本文介绍的是关于切片厚度的物理概念、临床意义及其标准化检测技术。一、声束切片厚度概念超声成像的基本原理告诉我们:当其频率达数兆赫兹,换能元件孔径达10mm以上时,超声波将在人体组织中成束传播,因而被称为"声束"或"波束"。A超探头和机械扇形扫描式B超探头采用的是单元式换     

腔内导管超声系统

腔内导管超声已用来评价很多病变,微探头可以置于血管腔内和非血管腔内来显示病变.二维基础上的三维重建在腔内超声图像中是一种新的方法.这篇综述将探讨腔内超声系统装置及一些进展.     

美国声学专利述评选译

1.用于形成图象的声纳换能器系统此主动声纳系统由高出海底2m左右的拖体载运。工作频率为2MHz,在2～10m距离内以45°扇面对海底前向区域扫描。它用一组(共5个)换能器21～25来实现这样的操     

基于统计法纹理描绘子的超声图像分割算法

超声C扫描成像中经常存在成像对比度低边缘模糊不清等现象,从而导致图像分割不完整。针对该问题,提出基于统计法纹理描绘子的图像分割算法。基于单晶探头C扫描成像中采样点之间声束重叠的特点,首先进行超声声束分析并且选取声束重叠数据;然后采用区域描绘子的相关纹理测度替代传统的幅值特征值,对采样区域中缺陷的特征信息进行描述,从而提高超声成像分辨率和对比度;最后采用数学形态学进行滤波,进一步提高缺陷的识别度。通过304不锈钢标准试块底面圆形盲孔C扫成像试验进行验证并与自适应阈值分割算法比较,实验结果显示该文算法可以得到清晰完整的缺陷分割区域,并且比自适应阈值分割算法更为有效可靠,尤其对于易忽略的小尺寸缺陷同样得到良好的分割效果。     

海底沉积物岩芯横向声学测量系统的标定

水平轴向测量技术相对成熟,但较难获取海底沉积物的无扰动分层声学特性,采用横向测量技术可以解决这一问题。文章研究了海底沉积物岩芯横向测量技术,将水作为海底沉积物测量的参考标准,进行测量系统的标定。提出了等效换能器的概念,将样品以外的声传播介质整合成等效换能器的一部分,标定测量等效换能器声延时和声传播初始能量。以水为标准介质,分别采用33、80、100 kHz三种频率的声学换能器,以及75、90、110 mm三种管径的聚氯乙烯(Polyvinyl Chloride,PVC),测量所得的水中的声速与标准计算水中的声速具有一致性,其中以采用80 kHz频率声学换能器和90 mm管径PVC管测量时的声速误差最小,选用此状态进行标定,得出当隔水耦合测量法换能器相对距离为142.02 mm时,标定的等效换能器声延时为45.88±0.08 μs,等效换能器声传播初始能量(以接收换能器的接收电压表示)为0.86±0.03 V。应用标定的等效换能器声延时和声传播初始能量测量海底沉积物。计算得到声速和声衰减系数符合黏土质粉砂的声学特性。     

基于阵列探测方式的时域光声成像系统

将阵列超声探头和超声相控技术与光声成像相结合的成像系统，与采用水听器的单探头旋转扫描光声成像系统相比，避免了机械旋转机构给光声信号采集所带来的不稳定性，提高了数据采集速度．时域光声信号由64阵元线阵超声探头以电子相控聚焦的方式进行线性扫描采集，然后通过时域后向投影算法进行光声图像的重建．采用波长532nm、重复频率10Hz的脉冲激光，系统可快速重建样品内部光学吸收分部的二维图像，单帧图像数据采集时间小于200s，成像横向分辨率小于2mm．实验结果表明，采用此方法可显著提高系统对光声信号的扫描稳定性和成像效率，该系统是一种有潜在临床应用价值的光声成像系统．     

铁电驻极体空气耦合声换能器的研制

基于多孔聚丙烯铁电驻极体薄膜系统研制了平面型和球型聚焦空气耦合超声波换能器。平面型换能器孔径为20mm,两个球型聚焦换能器的孔径和焦距分别为20mm和35mm、30mm和40mm。使用激光干涉仪测得了三个换能器作为发射器工作时的带宽和谐振频率,并且将在脉冲回波模式下测得的换能器作为接收机工作时的响应与激光干涉仪测试结果进行比较。最后选择孔径为20mm的球型聚焦换能器,在脉冲回波模式下对不同直径孔的聚乙烯阶梯楔进行扫描成像。     

光声层析成像技术的研究进展

光声层析成像技术是一种新兴的医学成像技术,具有高分辨率、高对比度、高穿透深度的优点。文章简要介绍光声层析成像技术的原理,并报道基于单聚焦换能器扫描的层析成像技术和基于多探元超声探测方式的层析成像技术,指出该技术在医学检测上具有重要的应用前景。     

乳腺非肿块型病变的超声临床分析

目的:评价乳腺非肿块型病变的超声反应。方法:采用回顾性分析的形式对我院于2018年1月-2018年12月期间,所收治的经常规检查确诊的患者共50例予以分析。结果 :20例非肿块型乳腺病变反应中,恶性病变11例(55%),良性病变9例(45%)。其中3例为浸润性导管癌、4例为导管内癌、淋巴转移性低分化癌3例、纤维性腺癌1例、淋巴细胞性白血病2例、增生2例、腺病4例、炎性病变1例。20例非肿块型乳腺病变中,12例为片状低回声区域(60%),8例为微钙化片状低回声区域(40%);恶性组病灶最大直径为2.25±1.03(cm),良性组为3.09±1.02(cm),良性病变组微钙化比例77.8%和恶性病变27.3%;腋下异常淋巴结分析,良性病变9.1%,恶性病变55.5%。结论:非肿块型乳腺病变内部微钙化存在对导管内癌诊断具有显著价值。腋下存在淋巴结异常对于良恶性病变鉴别诊断有一定作用。     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.     

Mechanism Study on the Wear of CrAlTiN Coated High-Speed Steel Twist Drills Under Dry Cutting Conditions

As demands about environment protection are growing up, dry cutting technology is getting more and more concerns from all over the world. Main works performed here are study on dry cutting performances and wear mechanisms of M2high-speed steel (HSS) twist drills with CrAlTiN multicomponent coatings, which was deposited using magnetron sputter ion plating system, in drilling 45 and 30CrMnSiA steel, and their comparisons to those in drilling the same steel but using monolayer CrN and commercial TiN coated drills. Drilling performances of drills are evaluated mainly through the measurements of width on outer corner flank land and the cutting forces. Results show that performances of CrAlTiN coated drills are better than those of monolayer CrN and TiN coated drills. In drilling 45 and 30CrMnSiA steel, the average tool life of the CrAlTiN coated drills are 17.2 and 11.8 times higher than those of the uncoated drills. Observing wear of the drill with scanning electronic microscope, results show that there is no crack or spallation of the CrAlTiN coatings in wear zones. Main mechanism of the wear here is adhesion.     

Study on Bond Ability of Arc-Spraying Coatings with Different Surface Pretreatment on Cast-Iron

Arc spraying coatings are widely used in various applications, but uncommon in cast iron substrate. Different surface pretreatment technology is tested on substrates of gray cast iron. Surface roughness and residual stress were measured by TR200 and X-ray diffraction analyzer. Influence of different surface pretreatment methods ( dry blasting and fusebond) on roughness and residual stress was analyzed. The arc-sprayed coatings of wire 3Cr13 (φ2mm) on gray cast iron substrate is studied. The microstructure and interface of bonding layer were observed by SEM. The bond strength was taken by tensile test. Results show that bond strength with grit blasting is higher than fuse-bond; it is feasible to make wire 3Cr13 coating with arc spraying on cast iron substrate roughened by grit blasting.     

Structural Characteristics of TiO2 Ceramic Coating by Micro-Plasma Oxidation

TiO2 ceramic coatings with thickness of 20 μm were formed on the surface of pure titanium by micro-plasma oxidation. Their micro-structures were investigated by by using X-ray diffraction and their surface images were detected by using scan electronic microscope. There were three kinds of TiO2 coatings, pure anatase type TiO2 phase, mixed phases consisted of rutile type TiO2 phase and anatase type TiO2 phase, pure rutile type TiO2 phase. The coating surface with the pure anatase type TiO2 phase is rough, while the coating surface with the pure rutile type TiO2phase is smooth. The upper coating surface with the mixed type TiO2 phases is anatase type TiO2 structure and the subsurface of the TiO2 coating is rutile type TiO2structure.     

Evaluation of fatigue life of steel using steel grain size

The insightful discussion of the relationship between the construction of metallographic and fatigue life and proposition of mathematical relationships describing this relationship was conducted in the paper. This paper presents a method for estimating the fatigue life, based on the construction of the microstructural material taking into account the grain size and the participation of ferrite and pearlite phase.