陀兴水库扩建后土坝坝基防渗方案研究

陀兴水库建于二十世纪六七十年代,工程分为两期,目前正在进行二期改扩建工程(正常蓄水位由53.23 m抬升到60 m)。根据水库现状条件和工程地质勘探成果拟定了两套防渗方案,并从渗流稳定、坝坡抗滑稳定以及工程投资等方面开展了对比研究。研究表明无论从渗透稳定、抗滑稳定还是工程投资方面方案2均优于方案1。研究成果可为工程的设计和施工提供参考。     

Improving Parsing of ‘BA’ Sentences for Machine Translation

The research on Chinese‐Japanese machine translation has been lasting for many years, and now this research field is increasingly thoroughly refined. In practical machine translation system, the processing of a simple and short Chinese sentence has somewhat good results. However, the translation of complex long Chinese sentence still has difficulties. For example, these systems are still unable to solve the translation problem of complex ‘BA’ sentences. In this article a new method of parsing of ‘BA’ sentence for machine translation based on valency theory is proposed. A ‘BA’ sentence is one that has a prepositional word ‘BA’. The structural character of a ‘BA’ sentence is that the original verb is behind the object word. The object word after the ‘BA’ preposition is used as an adverbial modifier of an active word. First, a large number of grammar items from Chinese grammar books are collected, and some elementary judgment rules are set by classifying and including the collected grammar items. Then, these judgment rules are put into use in actual Chinese language and are modified by checking their results instantly. Rules are checked and modified by using the statistical information from an actual corpus. Then, a five‐segment model used for ‘BA’ sentence translation is brought forward after the above mentioned analysis. Finally, we applied this proposed model into our developed machine translation system and evaluated the experimental results. It achieved a 91.3% rate of accuracy and the satisfying result verified effectiveness of our five‐segment model for ‘BA’ sentence translation. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

棉／Viloft／牛奶蛋白／Lyocell多组分喷气涡流纱的开发

文章研制开发了棉／Viloft／牛奶蛋白／Lyocell多组分喷气涡流（MVS）纱和环锭纱,并对两种纱线的强力、毛羽、耐磨等性能进行了测试,结果证明：MVS纱的毛羽指标明显优于环锭纱,尤其是2mm以上的毛羽指数;MVS纱的强度和断裂伸长率要比环锭纱稍低;MVS纱和环锭纱的耐磨性能相近;MVS纱的条干CV值比环锭纱好。     

基于CFRP层合板钻削轴向力时变曲线的钻头几何形状分析

为探索能够实现碳纤维增强复合材料（CFRP）层合板低损制孔的钻头几何形状,采用4种不同几何形状的钻头,对T800级CFRP层合板进行钻孔实验研究,分析了钻头几何形状对钻削轴向力的影响,探讨了钻削轴向力与分层损伤之间的关系。结果表明:轴向力归零速度与出口分层因子有较好的正相关性,可采用钻削轴向力归零速度来表征钻头几何形状对CFRP层合板钻孔的适用性能。同时,实验发现切削区域具有多阶段几何特征的钻头,在钻出工件底部时轴向力是分阶段缓慢归零,出口分层因子较小。      

用于TFT-LCD液晶显示的可调电荷泵设计

为了满足TFT-LCD液晶显示的驱动要求,设计了一种通过控制饱和区MOS管的导通电阻来调节输出电压的可调电荷泵。与传统的电荷泵相比,该电荷泵通过负反馈系统进行控制,具有输出可调、最少外围器件、低纹波、易于集成等优点。采用此可调电荷泵电路的芯片已在UMC0.6μm-BCD工艺线投片,测试结果表明,该可调电荷泵电路工作良好,独特的稳压方式使得电荷泵输出纹波降至最低,并且电荷泵的电容尺寸小,从而减小了整个系统的PCB面积,可调电荷泵正电压输出范围为10～30V,负电压输出范围为-5～-30V,负载电流为50mA时,输出纹波为27mV,可调电荷泵的整体效率可达80%。     

Temperature fluctuations and moisture migration in wheat stored for 15 months in a metal silo in Canada

Temperatures and moisture contents inside a metal silo filled with 20 t of wheat were monitored from August 2003 to October 2004 in Western Canada. In the summer and then repeated in the autumn of 2005, grain moisture contents inside small columns, inserted in the top of the grain bulk in the same metal silo, were measured after 4 and 8 weeks. The columns had the following configurations: 1) both the top and bottom of the column were open; 2) the top of the column was open and the bottom was sealed; and 3) the top of the column was sealed and the bottom was open.During the 15-month period, headspace temperature averaged 2.9 ± 0.2 °C higher than that of the ambient air with a maximum of 18.3 °C and a minimum of 0 °C. There was larger temperature fluctuation in the headspace than inside the grain mass. The average temperature gradient was 5.09 ± 1.24 °C/m inside the grain mass. The highest temperature gradient was 32.4 °C/m and it was located at the center of the bin at 1.6 m high. “Inside” grain had a lower moisture change than the surface grain.Grain in the top section of the column with the column configuration of Top End Open had the largest change of its moisture content, and grain in the middle section of the column with any of the configurations did not change. Grain inside the small columns at different locations in the silo had different moisture movement trends. These trends were consistent with the measured moisture migration in the entire silo. These results confirm that even in a small silo there were temperature gradients large enough to drive air movement and the induced convection currents could cause moisture migration.     

一种双层浮筏式南极望远镜运输减振方案设计

Dome A是南极内陆距海岸线最遥远的一个冰穹,具有极为重要的科考价值,但是从上海中国南极科考基地出发前往Dome A的道路振动加速度值十分巨大。首先,分析了从上海到南极的运输振动环境,确定了从南极泰山站到Dome A为重点的缓冲包装的关注范围,并提取了该区间测得的最大加速度值;其次,以南极巡天望远镜主镜室为包装减振对象,设计了一套双层隔振的浮筏式减振系统用于南极内陆地区的运输,根据相应的最大振动加速度值确定了减振系统的相应参数;最后,对其进行了静力学和动力学的模拟分析。2013年冬季在中国漠河地区进行了减振系统的运输实际测试,测试结果显示,该套系统可以满足南极巡天望远镜主镜的运输安全需求。     

冷却空气流向对CFRP制孔刀具磨损及孔质量的影响

在加工碳纤维增强树脂基复合材料（CFRP）时多用冷却工艺来提升加工质量。其中,空气冷却工艺因其方便性被广泛用于实际加工中。然而,目前尚缺少空气冷却方向对刀具磨损和加工质量的研究。文章通过控制冷却空气的方向,开展了干式切削、正向喷气和逆向吸气冷却条件下钻削CFRP材料的研究。获得了上述冷却条件对双顶角刀具第二主切削刃末端磨损的影响规律,发现气体冷却都能有效抑制刀具磨损,且在对出口温度影响相近的条件下,逆向冷却比正向冷却能够更好地抑制磨损。进而分析了冷却条件对钻削出口损伤的抑制效果,发现冷却、冷却方式对孔出口撕裂深度的抑制作用都较小,但逆向吸气冷却能够有效减小出口的毛刺高度,是一种有效提高制孔质量的冷却工艺。      

A low-distortion BiCMOS seventh-order Bessel filter operating at2.5 V supply

This paper presents the design of a seventh-order continuous-time Bessel filter using a new low-voltage and highly linear BiCMOS transconductor. A high-gain and parasitic-insensitive integrator is obtained by using an active capacitor scheme. The filter has been designed to operate at a 2.5 V supply with a nominal -3 dB cutoff frequency of 600 kHz. It has been fabricated in 1 μm, double-poly 6-GHz BiCMOS process. The inband group delay variation is less than 10 ns. The total harmonic distortion (THD) measured with a 100 kHz input signal is less than -49 dB for a 2 V_pp amplitude and the dynamic range is 77 dB. The filter can be frequency tuned over almost one decade with a gain variation less than 0.2 dB in the passband. A common-mode rejection ratio (CMRR) of 53 dB in the passband is observed, thanks to a careful common-mode control strategy