On the pop-in mode of fracture

Experimental observations concerning the pop-in mode of fracture obtained during an investigation of the fracture toughness of glassy plastics are related. Comments on the mechanics of the pop-in mode are presented.     

A comparison of estimators of output multipliers from incomplete input-output data

This paper presents derivations and empirical tests of three formulas for estimating output multipliers with only limited input-output type data. The first formula assumes only knowledge of the proportion of the value of output of the firm or industry in question which is respent within the region, as well as an estimate of the average of this value over all industries. The second formula assumes this value as well as the relative values of the I-O row totals. The third equation assumes data equivalent to a column in the I-O matrix is known for the specific firm or industry in question. The data requirements for all three formulas are modest but are more for (2) than for (1) and are more for (3) than for (2). All three formulas are shown to be quite reliable but the third gives especially close estimates of the actual multipliers for the several models tested. It is concluded that fairly rough estimates of the average interindustry proportion can be safely used but it is important to obtain the firm or industry expenditure (direct effects) data as accurately as possible.     

Solid-phase immune electron microscopy (SPIEM) for rapid viral diagnosis

Immune electron microscopy (IEM) is one of the fastest and most sensitive methods for the detection and diagnosis of viruses. This technique is based on formation of immune complexes of the virus with its corresponding antibody. In IEM optimal precipitation depends on a correct ratio, and there is a prozone effect. These problems can be overcome by using the solid-phase immune electron microscopic (SPIEM) technique. In this technique the antibody is attached to a particle which is used for 'fishing' the virus to be examined out of the suspension. After low speed centrifugation the preparation is treated either for observation in the transmission electron microscope or in the scanning electron microscope. In 'positive' samples the virus is seen attached to the surface of the particle. We report here results with S. aureus as the solid phase for the detection of Sindbis virus. The anti-Sindbis gamma globulins are attached to the bacteria by means of protein A present on their surface.     

On the least time control problem with interior output constraints

A variational problem arising in the study of least time controls is formulated in terms of norms of functionals on suitable Banach spaces. The existence of a solution is demonstrated by an appeal to the Hahn-Banach theorem, and the form of solution is developed from the equality conditions for Hölder's inequality. The systems being controlled are linear, but not necessarily time invariant, and the results may accordingly find application in the control of batch processing systems.     

Acid-base status in the toad Bufo viridis in vivo

The acid-base status in the toad Bufo viridis was assessed on blood samples taken through a chronical cannula from unrestrained animals. Blood gases and the pH were very constant in animals which were kept either under control conditions (free access to tap water) or immersed in shallow water. pH was 7.646 +/- 0.032 (mean +/- SEM) in 14 control toads at 26 degrees C. PCO2 was 13.1 +/- 1.2 mm Hg and [HCO3-] was 17.0 +/- 0.7 mmol/l at the same temperature. pH and PCO2 were independent of the hematocrit and the haemoglobin in the blood. Diamox induced a characteristic metabolic acidosis which is apprently the result of the inhibition of carbonic anhydrase both in the kidney and in the skin. The results are discussed in relation to the role of the kidney and the skin in regulating the acid-base balance in the toad.     

A Mechanized Proof Environment for the Convenient Computations Proof Method

A mechanized verification environment made up of theories over the deductive mechanized theorem prover PVS is presented, which allows taking advantage of the convenient computations method. This method reduces the conceptual difficulty of proving a given property for all the possible computations of a system by separating two different concerns: (1) proving that special convenient computations satisfy the property, and (2) proving that every computation is related to a convenient one by a relation which preserves the property. The approach is especially appropriate for applications in which the first concern is trivial once the second has been shown, e.g., where the specification itself is that every computation reduces to a convenient one. Two examples are the serializability of transactions in distributed databases, and sequential consistency of distributed shared memories. To reduce the repetition of effort, a clear separation is made between infrastructural theories to be supplied as a proof environment PVS library to users, and the specification and proof of particular examples. The provided infrastructure formally defines the method in its most general way. It also defines a computation model and a reduction relation—the equivalence of computations that differ only in the order of finitely many independent operations. One way to prove that this relation holds between every computation and some convenient one involves the definition of a measure function from computations into a well-founded set. Two possible default measures, which can be applied in many cases, are also defined in the infrastructure, along with useful lemmas that assist in their usage. We show how the proof environment can be used, by a step-by-step explanation of an application example.     

Time-Division Multilevel Multiplexing Communication Method

We propose a method that combines time division with multilevel signals in order to increase the channel capacity efficiently. This combined method enables increasing the bandwidth by a factor of , being the number of levels of the multilevel signal or alternatively enabling the transmission of independent channels, or any combination between both. This method increases bandwidth cost effectiveness and reduces the impact of fiber chromatic dispersion.     

处理器与音视频外设之间的连接

数字信号处理器以需要大量I/O负载的应用为目标,通常为开发人员提供各种集成接口一某些是标准接口,另外一些则是专用接口.例如,美国模拟器件公司(ADI)的Blackfin系列处理器是会聚处理器,这意味着它们在一个芯片上集成了DSP与MCU功能,这些处理器拥有与音频应用相关的两种主要类型的串行接口.该处理器的低比特速率双线接口(TWI)与串行外设接口(SPI)模块是用于音频器件控制与配置的.这些外设接口的前向通道通常用于配置或控制音频转换器,而反向通道则主要负责传输转换器的反馈信息或状态信息.该处理器的高比特速率串行端口外围电路,通常用于执行音频数据传输.