基于PIC16C71的数字水温配制阀的设计

设计了一种基于PIC16C71单片机的数字水温配制阀。该配制阀采用NTC热敏电阻作温度传感器,与固定电阻组成简单分压电路作为水温测量电路,利用PIC16C71单片机内置的8位A/D转换器把热敏电阻上的模拟电压转换为数字量,PIC16C71单片机控制直流电机驱动混水阀调节冷热水的混合比例实现水温调节。给出了控制电路图,对水温测量电路的参数选择和测温精度作了详细讨论。实验和分析表明,选用阻值较大的NTC热敏电阻和分压电阻可较好地解决热敏电阻因功耗较大造成的热击穿问题。     

肠道病毒71型甘肃分离株VP1基因特征分析

目的分析肠道病毒71型(Enterovirus,EV71)甘肃分离株VP1基因的特征。方法应用RT-PCR法扩增4株EV71甘肃分离株(46F、47F、51F和55F)的VP1基因,克隆入pTA2载体,进行核苷酸序列测定,并进行序列的同源性比较及进化树分析。结果 4株病毒VP1核苷酸序列长度均为891bp,推导的氨基酸序列含297个氨基酸。51F与55F毒株核苷酸和氨基酸同源性均为100%,46F与47F的同源性分别为99.6%和99.0%,4株病毒与EV71的C4亚型毒株核苷酸同源性在96%以上,氨基酸同源性在99%以上。同源性和进化树分析显示,4株分离株分属2个群,其中51F和55F毒株同属一个群,其与昆明分离株kunming41-08亲缘关系最为相近;46F和47F同属一个群,其与内蒙分离株0723F/NM/CHN/07关系最为相近。结论 4株EV71甘肃分离株属于C4亚型,为中国EV71的基因分型、分子流行病学研究提供了参考。     

不同温度培养的3株EV71毒株的增殖动力学分析

目的对不同温度培养的3株EV71中国流行株的增殖动力学进行分析。方法分别在32、35、37和40℃条件下对FY23、K9和S1株EV71进行传代培养、2～24h培养及噬斑培养,采用微量滴定法测定病毒的感染性滴度;传代培养的子代病毒通过脑内注射方式感染新生ICR乳鼠,观察病毒的致病性。结果传代培养时,在32和40℃培养的3株病毒致细胞完全病变时间较35和37℃延长,且子代病毒滴度下降,35℃培养的病毒滴度较37℃升高;3株病毒培养24h后,37℃培养的病毒增殖效率最高,35℃次之,40℃最低;4个温度培养的病毒噬斑形态无明显变化;新生乳鼠脑内注射致死率差异无统计学意义(P>0.05)。结论培养温度的变化可影响EV71的致细胞病变速度及子代病毒的增殖,但对病毒噬斑的形态及新生乳鼠的致病能力无明显影响。     

Alfred Swaine Taylor (1801–80)

Abstract

After a period in decline the Portobello Road market in London has enjoyed a revival in the past two or three years. There are at least three dealers in historic photographs within fifty yards of an East Anglian couple who regularly bring good quality decorative antiques and other curios to sell on Saturday mornings. I stopped at their showcase, looked in, walked on, and then returned to take a second look at a scrapbook, so often a source of good printed ephemera. It was open at a page showing a comic drawing of a wagon done up as an itinerant photographer's studio. I was told how much the scrapbook was and spent the next ten minutes looking through it. I decided on balance that I could ‘just about see the price in it’ ignoring the four photographs, which I believed must be of little or no value. On reaching my car I had another look through the album. A negative image of a leaf (figure 1) looked interesting, for a few months earlier I had been to Lacock and now remembered Talbot's photogenic drawings. Examination of the engravings and lithographs showed that they started in the 1820s and ended in 1853. This was undoubtedly a girl's scrapbook begun when she was quite small and probably continued until her early teens when the enthusiasm for pasting was bound to wane. I settled on a probable year of birth of 1840 for the girl but most careful combing discovered no name or initials in the book. There were, however, some postcards celebrating a pageant in 1907 at Bury St Edmunds, Suffolk, and one had been posted to a Mrs F. Methold at an address in Bury, but how she was connected with the book remained to be disovered. I looked once more through the printed ephemera and spotted that two cards with heavily embossed borders had small hand-coloured lithographs pasted on to them. My suspicion that these were early Victorian invitations proved to be correct. Removing the little pictures revealed that they were invitations from the Pharmaceutical Society to Alfred S. Taylor, FRS, to attend two dinners dated May 1848 and July 1849. I did not think that it was straining common sense to conclude that father had given his daughter these old invitations for her scrapbook.     

施耐德ATV71变频器在球团生产线POLYCOM高压辊磨机上的应用

本文介绍了施耐德ATV71变频器在球团生产线POLYCOM高压辊磨机上的应用,经过测试,产能也完全达到设计要求,辊磨机中压变频器运行良好,为球团高效生产提供了设备保障。     

AZ71镁合金TIG焊焊接接头微观组织与力学性能

采用钨极氩弧焊接方法对2.2mm厚镁合金AZ71薄板进行焊接加工。焊后对接头进行拉伸试验和硬度测试,结果表明:采用90A的电流焊接时,接头抗拉性能最好(281.23MPa),达到母材的89.58%。断裂发生在焊缝区,焊接接头断口呈准解理断口,接近解理断口;母材断裂为延性断裂,断口呈韧窝断口;焊缝区显微硬度最高,其次是母材,热影响区硬度最低。     

Performance of cable-stayed bridge pylons subjected to blast loading

Since the terrorist attacks of 2001, concern about potential car bomb attacks on buildings and infrastructure such as bridges and tunnels has increased tremendously. Design for better performance of these structures subjected to blast load is important to prevent progressive collapse of the structure and catastrophic loss of lives. The objective of this research was to study the performance of hollow steel box and concrete-filled composite pylons of a cable-stayed bridge subjected to blast loads. Car bomb detonation on the deck is assumed to be the most likely scenario to occur. A coupled numerical approach with combined Lagrangian and Eulerian models was used to consider the interaction of the deck and pylon with the air that transfers the explosion effect to the bridge. The non-linear explicit finite element analysis program, MD Nastran SOL700 was used to simulate the spatial and time variation of the blast load as well as blast shock wave-bridge interaction response. The blast resistance of two different types of pylons was investigated in a comparative study. The study established damage patterns of the pylon and showed superior performance of the concrete-filled composite pylon over the hollow steel box pylon. For the hollow steel box pylon, the P-Δ effect on the instability of the pylon subjected to blast load was significant.     

Chebulagic Acid,a Hydrolyzable Tannin,Exhibited Antiviral Activity in Vitro and in Vivo against Human Enterovirus 71

Human enterovirus 71 is one of the major causative agents of hand, foot and mouth disease in children under six years of age. Presently, no vaccines or antiviral drugs have been clinically available to employ against EV71. In this study, we demonstrate that treatment with chebulagic acid reduced the viral cytopathic effect on rhabdomyosarcoma cells with an IC₅₀ of 12.5 μg/mL. The utilization of the chebulagic acid treatment on mice challenged with a lethal dose of enterovirus 71 was able to efficiently reduce mortality and relieve clinical symptoms through the inhibition of viral replication. Chebulagic acid may represent a potential therapeutic agent to control infections to enterovirus 71.     

生物反应器培养Vero细胞生产肠道病毒71型

目的研究利用微载体技术规模化制备肠道病毒71型(Enterovirus 71,EV71)的方法。方法利用NBSCelliGen 310 5 L生物反应器进行Vero细胞微载体培养,考察了不同微载体Cytodex-1浓度(3、10、15、20 g/L)对Vero细胞生长代谢及细胞密度的影响,并且与细胞工厂(Cell factory,CF)中Vero细胞染毒后的病毒繁殖进行比较。分别采用上清液、洗涤液、洗脱液模式收毒,比较不同收毒方式中EV71的抗原含量及病毒滴度(CCID50)。结果采用10 g/L微载体浓度,批次培养方式培养Vero细胞120 h后,细胞密度可达5.47×106个/ml;当微载体浓度大于15 g/L时,由于葡萄糖消耗速度快,需采用灌注模式培养。按MOI 0.2染毒后,微载体培养的收毒时间比CF慢48 h,但其病毒滴度可达8.8 Log10CCID50/ml,约为CF的5倍。EV71与微载体存在离子交换吸附作用,按上清液加洗脱液方式收毒,抗原总量可达12 61 U/ml,约为CF的3倍。结论已成功建立了生物反应器微载体5 L发酵培养Vero细胞生产EV71的方法,为进一步EV71大规模培养以及疫苗研发奠定了基础。