选择测试阀在现场测试中的应用

选择测试阀是新一代全通径压控式测试器，在结构和性能上有了本质的创新，使现场操作更加简便、安全，对井筒条件要求低，更适用于高温、高压、深井、气井的地层测试，拓宽了地层测试和其它井下作业的兼容性。经7井次应用，其安全性、可靠性越来越得到认可。     

构造矩形微带贴片天线的展开基函数

本文介绍了如何构造矩量法展开基函数的一种方法- 空腔模型法.文中首先根据空腔模型所得到的内部场结构推导出贴片表面电流的表达式,然后与文献中已有的计算结果和实验结果相比较.计算结果与实验结果相当吻合,并且比文献 [7]的计算结果更具有精确性,从而验证了本文所述方法的正确性.     

微生物实验室防止污染扩散的设计与效果检测

介绍了建造的微生物实验室的布局与防气溶胶污染扩散措施、安全操作箱(初级防护)与负压室(次级防护)对噬菌体气溶胶有很好的防扩散效果。所用二次过滤装置滤效可达99.99％～100％。     

风往北吹——北国春城数码印象

当起笔写这段文字的时候，我却已离开北方，窝在南方潮湿阴冷的房间里怀念那个干爽明媚有着蓝天白云的北方。记忆是从零散的文字与图片间交叉进行的。     

The influence of varying degrees of adhesion as determined by mechanical tests on the sensory and consumer acceptance of a meat product

The adhesion between meat pieces in meat products, varied by the addition of different concentrations of a crude myosin solution, was measured by a trained sensory panel and by two instrumental tests: tensile adhesive strength (TAS) and punch and die. A consumer trial was used to find which level of adhesion was preferred. Results from the sensory panel showed that the adhesion could be detected as highly significant (P < 0·001) differences in three tactile measurements and in the two eating qualities, ease of fragmentation and rubberines. TAS measurements gave larger differences between treatments than punch and die, and had very high correlations with ease of fragmentation and crumblines on cutting. The small consumer study revealed no overall preference for any one product. Hence, although differences in adhesion between meat pieces in a meat product are detectable subjectively and can be measured objectively by TAS tests, preference for any particular strength varies between individuals.     

蒸汽与魔法的对抗 探秘新魔幻网游《黑金》

继大型3D武侠网游《九阴真经》成功推出之后,游戏蜗牛于近日又公布了旗下最新3D魔幻网游《黑金》的一系列背景资料和画面、视频。作为蜗牛又一款里程碑式的超前作品,《黑金》所采用的3D引擎在《九阴真经》"Flexi"的基础上进行了升级优化,并由中、俄顶尖团队联合研发,其创作阵容和技术储备显然要比之前所有的产品都更为抢眼。同时,游戏中浓厚纯正的蒸汽朋克文化氛围、动态的世界体系和战斗模式,以及史诗般庞大的罕见故事背景等所有核心特色,都是对目前国内乃至国际游戏市场上传统魔幻题材网游所进行的大胆突破,并已先后在E3、CJ和GC等多个国内外知名游戏展上初露锋芒。     

The strength and stiffness of perimysial connective tissue isolated from cooked beef muscle

Thick transverse slices of bovine M. semitendinosus were cooked for 1 h at 50°–90° and then cooled. Perimysial connective tissue was dissected from the cooked meat and subjected to mechanical testing in a small-scale device. The initial ‘toe’ region of the J-shaped load-extension curve was progressively lost with increasing temperature, the curve becoming more nearly linear after cooking at 90°C. These effects are explained on the basis of the progressive straightening out of the crimps from the collagen fibres, the crimps becoming finally lost at approximately 70°C. The final stiffness of the perimysium at greater extensions was unchanged at higher temperatures. Breaking strength increased from raw to cooked at 50°C, thereafter decreasing at cooking temperatures up to 90°C. it is proposed that this technique of testing isolated perimysium gives a valuable means of directly measuring the effects of cooking, or other treatments, on the intrinsic properties of perimysial collagenous material. Quantitative knowledge of these will help to determine its contribution to the overall mechanical properties, and hence eating quality, of cooked meat.     

Tissue characterization based on scatterer number density estimation

The authors propose a robust model for characterizing the statistical nature of signals obtained from ultrasonic backscatter processes. The model can accommodate frequency-dependent attenuation, spatially varying media statistics, arbitrary beam geometries, and arbitrary pulse shapes. On the basis of this model, statistical schemes are proposed for estimating the scatterer number density (SND) of tissues. The algorithm for estimating the scatterer number incorporates measurements of both the statistical moments of the backscattered signals and the point spread function of the acoustic system. The number density algorithm has been applied to waveforms obtained from ultrasonic phantoms with known number densities and in vitro mammalian tissues. There is an excellent agreement among theoretical, histological, and experimental results. The application of this technique for noninvasive clinical tissue characterization is discussed.     

Fracture toughness of frozen meat

The fracture toughness and dynamic mechanical moduli of frozen beef M. semitendinosus were investigated at various sub-zero temperatures using several different test geometries. Traditional fracture mechanics methods were considered inapplicable to frozen meat, since considerable plastic flow occurs in addition to elastic deformation and fracture. Graphical work area methods still apply, based on calculating areas under load-deflection diagrams to measure the energy used up to fracture. Total work to fracture was found to vary both with temperature and geometry, with a peak occurring between -10°C and -15°C. It was shown that it is possible to separate out the components of fracture and flow using two methods: microtome cutting and compact tension. In microtome cutting, the cutting energy was found to depend on the thickness of cut, increasing linearly from 50 μm to 500 μm. This variation is attributed to a dependence of the volume of the plastic zone size at the cutting tip on the thickness. By extrapolation to zero thickness, an essential value of fracture energy of approximately 100J/m(2) was determined, assuming the absence of large-scale plastic yielding. It was also possible to determine a value for the essential work of fracture using graphical work area methods in compact tension, obtaining values between 100 and 200 J/m(2). Dynamic mechanical testing showed loss peaks in mechanical damping occurring between -5°C and -10°C, with both temperature and magnitude of these peaks varying with frequency. Cryo-scanning electronic microscopy showed evidence of the nature of the fracture transition within frozen meat, indicating ductile deformation at higher temperatures (above -15°C), and brittle fracture at lower temperatures (below -15°C).