Planar-optical mesh-connected tree interconnects: a feasibility study

The mesh-connected tree is a two-dimensional interconnect topology that combines aspects of a conventional tree network and a two-dimensional nearest-neighbor mesh network. Because of its topological features, a mesh-connected tree has the potential to be implemented with planar optoelectronic interconnect concepts. We examine the feasibility of employing vertical-to-surface-transmissionelectro-photonic optical array switches together with planar micro-optical components for the future implementation of an optoelectronic mesh-connected tree interconnect.     

VCSEL-array-based angle-multiplexed optoelectronic crossbar interconnects

A large crossbar switch, which is a desirable building block for any low-latency interconnect network, is difficult to implement because of many practical problems associated with digital electronics. We propose a new method for implementing a large optoelectronic crossbar interconnect to take advantage of a unique principle of optics. Based on an emerging vertical-cavity surface-emitting laser (VCSEL) technology, a passive angle-multiplexed beam-steering architecture is proposed as a key component of the optoelectronic crossbar. Various optical system parameters are evaluated. Because there is no optical fan-out power loss, the interconnect capacity of the proposed system is determined by the diffraction-limited receiver power cutoff, and therefore interconnection of more than 1000 nodes with a per node bandwidth of 1 GHz is possible with today's technology. A 64-element VCSEL-array-based proof-of-principle optical system for studying the interconnect scalability has been built. Details of the features of the proposed system, its advantages and limitations, demonstration experimental results, and their analyses are presented.     

Actin-titin interaction in cardiac myofibrils: probing a physiological role

The high stiffness of relaxed cardiac myofibrils is explainable mainly by the expression of a short-length titin (connectin), the giant elastic protein of the vertebrate myofibrillar cytoskeleton. However, additional molecular features could account for this high stiffness, such as interaction between titin and actin, which has previously been reported in vitro. To probe this finding for a possible physiological significance, isolated myofibrils from rat heart were subjected to selective removal of actin filaments by a calcium-independent gelsolin fragment, and the "passive" stiffness of the specimens was recorded. Upon actin extraction, stiffness decreased by nearly 60%, and to a similar degree after high-salt extraction of thick filaments. Thus actin-titin association indeed contributes to the stiffness of resting cardiac muscle. To identify possible sites of association, we employed a combination of different techniques. Immunofluorescence microscopy revealed that actin extraction increased the extensibility of the previously stiff Z-disc-flanking titin region. Actin-titin interaction within this region was confirmed in in vitro cosedimentation assays, in which multimodule recombinant titin fragments were tested for their ability to interact with F-actin. By contrast, such assays showed no actin-titin-binding propensity for sarcomeric regions outside the Z-disc comb. Accordingly, the results of mechanical measurements demonstrated that competition with native titin by recombinant titin fragments from Z-disc-remote, I-band or A-band regions did not affect passive myofibril stiffness. These results indicate that it is actin-titin association near the Z-disc, but not along the remainder of the sarcomere, that helps to anchor the titin molecule at its N-terminus and maintain a high stiffness of the relaxed cardiac myofibril.     

A Geometric Strategy Algorithm for Orthogonal Projection onto a Parametric Surface

Journal of Computer Science and Technology - In this paper, we investigate how to compute the minimum distance between a point and a parametric surface, and then to return the nearest point (foot...     

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河道砂体储层预测分析——以FLQ地区为例

储层横向预测的关键是波阻抗反演,各种基础资料品质的好坏直接影响反演精度。在构造解释成果基础上,结合该地区的地质状况和地震资料对储层进行基于模型波阻抗反演,以波阻抗反演得到的砂体分布范围为依据,对泉一段进行横向预测研究。结合沉积相分析成果,为寻找有利目标奠定了基础,建立一套沉积相-地震储层预测-地震地质解释三位一体的隐蔽油气藏勘探开发新思路。     

Reusable unit process life cycle inventory for manufacturing: grinding

This paper is a part of a series in which the goal is to provide users with calculation tools to estimate the energy use and mass loss of one unit process in a full manufacturing line. It is known as a unit process life cycle inventory (UPLCI). As such, this information is reusable in a wide range of products made of different materials. Grinding is the first UPLCI in this series, which is in the mass reduction category of the taxonomy of manufacturing processes. The energy calculations are not limited to the active or tip grinding energy, but include idle and basic energy values. In addition, an example calculation is provided to assist the UPLCI reader. The UPLCI can then be connected to others to estimate whole product manufacturing sequences.     

Temperatures and wear mechanisms in dressing of vitrified bonded grinding wheels

For the first time dressing temperatures were measured directly in the contact zone of grinding and diamond dressing tool. With average temperatures of 400 °C and maximum temperatures of 810 °C without cooling lubricant, the need to cool the dressing tool sufficiently is affirmed. For a diamond dressing tile and form rollers in contact with vitrified bonded corundum and CBN wheels, the main grit wear mechanisms were adhesions instead of breakage or high volumetric splintering. Extensive analyses proved that components of the grinding wheel bonding and abrasives were molten during the dressing process and solidified amorphously. This verifies high peak surface pressures and flash temperatures.