松树之间

<正>在墨西哥Valle de Bravo一处茂密的丛林中,五栋假日住宅散布于此。它们顺应着场地的环境,在松树林与风的回声中静静屹立。五栋住宅采用完全相同的内部结构,其内部六个功能区相互连接围合出中央天井。该中庭享有良好的视野,静谧的氛围,和亲密的舒适感。位于北侧的建筑内部空间相对私密,而南侧则向自然充分开放。低层坐落着客厅,餐厅,厨房和一间融入外部露台、中庭和花园的卧室。顶层三间卧室面向松树林迎接美丽的自然景观。建筑材料源自于当地的砖,木和泥土。     

Classification of heat treatable parts

Conclusions The classification of heat treated parts on the basis of common principles of technological classification facilitates the development and wide adoption of standard heat treatment processes and the organization of production on a scientific basis.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 5, pp. 2–9, May, 1973.     

The effect of baking soda/hydrogen peroxide dentifrice (Mentadent) and a 0.12 percent chlorhexidine gluconate mouthrinse (Peridex) in reducing gingival bleeding

The purpose of this study was to determine the effectiveness of a baking soda/hydrogen peroxide dentifrice, Mentadent, and a 0.12 percent chlorhexidine gluconate mouthrinse, Peridex, in reducing gingival bleeding. Forty subjects were divided into three groups; the baking soda group, the chlorhexidine group and the control group. All groups received oral hygiene instruction and brushed and flossed three times per day. Bleeding point scores were evaluated at baseline and at five weeks. The baking soda/hydrogen peroxide group used the supplied dentifrice as their sole toothpaste. The 0.12 percent chlorhexidine group used the mouthrinse twice per day. The control group performed oral hygiene as instructed. At five weeks, the 0.12 percent chlorhexidine mouthrinse significantly reduced gingival bleeding. The dentifrice and control groups revealed no statistically significant reductions. The results indicate that the 0.12 percent chlorhexidine mouthrinse is useful in improving oral health, whereas the baking soda/hydrogen peroxide dentifrice offered no advantages to conventional oral hygiene.     

Medical grade tubing: Criteria for catheter applications

In 1990 there were approximately 710 million catheter units produced world-wide from a variety of materials. This number is expected to increase 5–7% in 1991. Intravenous catheters are currently being produced from a myriad of materials including polyurethanes, polyvinylchloride, silicone rubber, and Teflon®, to name a few. Along with the ultimate end usage of a catheter, many other performance characteristics must be evaluated. Some of these characteristics are mechanical and physical properties, surface properties, hemocompatibility, biostability, and processability. The Vialon® biomaterial has a tensile strength of 520 kg/cm² which is over 50% higher than the other materials studied. This bioengineered material, which is a member of the broad class of polyurethanes, also gave better hemocompatibility properties, as measured by in vivo platelet deposition. In addition Vialon® is engineered such that the material softens in the body's moisture and heat rendering it biocompatible. The thermoplastic nature of this polymer also allows its ease of processing by such conventional means as thermal extrusion. A comparison of the aforementioned materials against these and other performance criteria was undertaken and will be presented.     

Carrier Phase Error in Single Sideband-Partial Response Systems

This paper studies the effect of a demodulator carrier phase error on the performance of a synchronous data transmission system. Various single sideband-partial response systems are ranked on the basis of their sensitivity to the phase error. Mean-square distortion due to the phase error and the vertical eye opening of the resulting eye patterns are used as performance measures of comparison. The influence of system bandwidth on the system performance is also studied.