新型骨架式轿车车身开发研究进展

新型骨架式车身主要由骨架和蒙皮组成，它具有减少模具制造成本、缩短开发周期、减轻质量等优点。本文总结了骨架式车身在国内外的研究进展，重点讨论了开发这种骨架式车身的几个关键技术，包括车身新材料如高强度钢板、铝合金以及拼焊板的开发和应用技术，新工艺如温成形、液压胀形、蒙皮与骨架的连接技术的研究。     

Counter-current air-water flow in narrow rectangular channels with offset strip fins

Counter-current two-phase flows of air-water in narrow rectangular channels with offset-strip fins have been experimentally investigated in a 760 mm long and 100 mm wide test section with 3.0 and 5.0 mm gap widths. The two-phase flow regime, channel-average void fractions and two-phase pressure gradients were studied. Flow regime transition occurred at lower superficial velocities of air than in the channels without fins. In the bubbly and slug flow regimes, elongated bubbles rose along the subchannel formed by fins without lateral movement. The critical void fraction for the bubbly-to-slug transition was about 0.14 for the 3 mm gap channel and 0.2 for the 5 mm gap channel, respectively. Channel-average void fractions in the channels with fins were almost the same as those in the channels without fins. Void fractions increased as the gap width increased, especially at high superficial velocity of air. The presence of fins enhanced the two-phase distribution parameter significantly in the slug How, where the effect of gap width was almost negligible. Superficial velocity of air dominated the two-phase pressure gradients. Liquid superficial velocity and channel gap width has only a minor effect on the pressure gradients.     

A Study of the flow phenomenon of water in a channel with flat plate obstruction geometry at the entry

The flow ina parallel walled test channel, when obstructed with a geometry at the entrance, can be forward, reverse and stagnant depending on the position of the obstruction. This interesting flow phenomenon has potential benefit in the control of energy and various flows in the process industry. In this experiment, the flat plate obstruction geometry was used as an obstruction at the entry of the test channel. The parameters that influence the flow inside and around the test channel were the gap (g) between the test channel and the obstruction geometry, the length (L) of the test channel and the Reynolds number (Re). The effect of the gap to channel width ratio (g/w) on the magnitude of the velocity ratio (V₁/V₀ : velocity inside/ velocity outside the test channel) was investigated for a range of Reynolds numbers. The maximum reverse flow observed was nearly 20% to 60% of the outside velocity for Reynolds number ranging from 1000 to 9000 at g/w ratio of 1.5. The maximum forward velocity inside the test channel was found 80% of the outside velocity at higher g/w ratio of 8. The effect of the test channel length on the velocity ratio was investigated for different g/w ratios and a fixed Reynolds number of 4000. The influence of the Reynolds number on the velocity ratio is also discussed and presented for different gap to width ratio (g/w). The flow visualisation photo-graphs showing fluid motion inside and around the test channel are also presented and discussed.     

有芯工频炉酸性炉衬对生产欧元材料的影响

通过对有芯工频炉酸性炉衬生产欧元材料出现的问题进行分析，发现在使用有芯工频炉酸性耐火材料时，炉衬寿命大大缩短，并使铜液Si含量超标，造成材料报废。而炉衬材料换成中性耐火材料时，基本上控制了Si含量，达到了欧元材料标准，并使炉衬寿命大大提高。     

Ti:LiNbO_3扩散条带光波导的变分分析

本文利用变分技术将Ti:NbO_3条带波导的波导模场分布分解成为两个相关的一维问题.对模参数和传播常数提供一种新的迭代近似方法.本方法收敛速度非常快,它对具有矩形横截面的光波导和扩散条带波导都适用。     

海水有鳞鱼皮制革工艺的初步研究

本文针对海水有鳞鱼皮的组织构造特征,对鱼皮制革工艺过程中的几个主要工序以及如何保持鱼皮特有的外观花纹,提高鱼皮产品高附加值等问题进行了初步研究,并对我国鱼皮制革的开发提出了几点建议。     

基于E1信道的图像传输系统的设计

本文提出了利用E1信道进行图像传输的方法,介绍了舆系统的工作原理,对视频编码器进行了较为详细的分析,并采用数字信号处理器作控制器,实现图像的实时传输。     

A novel distributed scheduling scheme for OFDMA uplink using channel information and probabilistic transmission

Distributed uplink scheduling in OFDMA systems is considered. In the proposed model, mobile terminals have the responsibility of making their own transmission decisions. The proposed scheme is based on two dimensional reservation in time and frequency. Terminals use channel state information in order to favor transmissions over certain subchannels, and transmission is done in a probabilistic manner. The proposed approach provides more autonomy to mobile devices in making transmission decisions. Furthermore, it allows avoiding collisions during transmission since it leads to collision detection during the resource reservation phase. The proposed approach is compared to other random access methods and shown to be superior in terms of increasing sum-rate, reducing the number of users in outage, and reducing the collision probability in the reservation phase.     

人体皮肤对激光镜式反射的实验研究

实验证实人体皮肤对激光具有镜式反射。     

In vivo confocal fluorescence imaging of skin surface cellular morphology: a pilot study of its potential as a clinical tool in skin research

The cellular morphology of the stratum corneum was studied in vivo using a novel imaging technique that uses confocal fluorescence microscopy in combination with topical application of a fluorescent contrast agent. Images obtained with this method show a strong variation in skin surface cellular morphology among healthy subjects. The results of several clinical studies suggest that cellular morphology is affected by the efficiency of the process of desquamation. As such, cellular morphology shows strong potential to serve as an indicator of skin health that yields mechanistic insight into the origins of skin ailments, such as xerosis, and the effectiveness of their treatments.