690V变频器在造纸厂的应用

在大型造纸厂经常会遇到使用200~1 000 k W变频电动机的情况。因为0.38 k V电机生产工艺的原因不可能做到很大功率,而中压(10 k V,6 k V)的变频器因为价格、安全与稳定性的原因也有其缺陷,所以0.69 k V这个电压等级的变频器就有了用武之地。     

The Real-World Safety Potential of Connected Vehicle Technology

Objective: This article estimates the safety potential of a current commercially available connected vehicle technology in real-world crashes.

Method: Data from the Centre for Automotive Safety Research's at-scene in-depth crash investigations in South Australia were used to simulate the circumstances of real-world crashes. A total of 89 crashes were selected for inclusion in the study. The crashes were selected as representative of the most prevalent crash types for injury or fatal crashes and had potential to be mitigated by connected vehicle technology. The trajectory, speeds, braking, and impact configuration of the selected in-depth cases were replicated in a software package and converted to a file format allowing “replay” of the scenario in real time as input to 2 Cohda Wireless MK2 onboard units. The Cohda Wireless onboard units are a mature connected vehicle technology that has been used in both the German simTD field trial and the U.S. Department of Transport's Safety Pilot project and have been tuned for low false alarm rates when used in the real world. The crash replay was achieved by replacing each of the onboard unit Global Positioning System (GPS) inputs with the simulated data of each of the involved vehicles. The time at which the Cohda Wireless threat detection software issued an elevated warning was used to calculate a new impact speed using 3 different reaction scenarios and 2 levels of braking.

Results: It was found that between 37 and 86% of the simulated crashes could be avoided, with highest percentage due a fully autonomous system braking at 0.7 g. The same system also reduced the impact speed relative to the actual crash in all cases. Even when a human reaction time of 1.2 s and moderate braking of 0.4 g was assumed, the impact speed was reduced in 78% of the crashes. Crash types that proved difficult for the threat detection engine were head-on crashes where the approach angle was low and right turn–opposite crashes.

Conclusions: These results indicate that connected vehicle technology can be greatly beneficial in real-world crash scenarios and that this benefit would be maximized by having the vehicle intervene autonomously with heavy braking. The crash types that proved difficult for the connected vehicle technology could be better addressed if controller area network (CAN) information is available, such as steering wheel angle, so that driver intent can be inferred sooner. More accurate positioning in the real world (e.g., combining satellite positioning and accelerometer data) would allow the technology to be more effective for near-collinear head-on and rear-end crashes, because the low approach angles that are common in such crashes are currently ignored in order to minimize false alarms due to positioning uncertainty.     

The behavioral component in the meaning of places

How do people think about the physical setting in the world around them? Part of the answer to this question may be in terms of the behaviors that occur there. To explore people's knowledge of behavior—place associations, twenty places (shown via color photographs) were assessed in five ways: (a) ratings of the place's suitability for each of eleven behaviors, (b) ratings of the expected frequency of occurrence of the eleven behaviors, (c) free listings of reasons for going to each place, (d) free listings of activities-while-there and (e) free listings of activities associated with the place. Results showed that people can distinguish places on the basis of behaviors, that the behavioral component of place meaning is composed of distinct aspects, and that knowledge of behavior is related to a global, overall representation of a place.     

用改良彗星试验检测工业废水的DNA损伤作用

采用改良彗星试验直接检测了多种工业废水不所引起的Ｖ７９细胞ＤＮＡ损伤。结果表明,所测的种各工业废话水均含有ＤＮＡ损伤剂,能够诱发培养的Ｖ７９细胞ＤＮＡ链断裂,其中以制革厂不的ＤＮＡ损伤作用最强。本研究显示出改良彗星试验在综合评价各种废水遗传毒性方面具有广阔的应用前景。     

上海市若干环境污染物的诱变性

用中国仓鼠肺成纤维细胞(V_(79)),进行次黄嘌呤—鸟嘌呤磷酸核糖转移酶位点(HGPRT Locus)试验,检测了上海市若干环境污染物的诱变性。结果发现,污染物量与诱变性之间呈剂量—反应关系。所有样品经代谢活化后(加S_9),其诱变性均有增高的趋势。卷烟焦油、油烟冷凝物的T/C值均>3,而不加S_9的黄浦江水和自来水样,则对V_(79)细胞可能具有间接的诱变作用(T/C值<3)。     

改性膨润土和沉水植物联合作用处理沉积物磷

首次将改性膨润土（modified bentonite,MB）作为原位吸附材料与沉水植物苦草（Vallisneria spiralis,V.spiralis）联合处理沉积物磷.研究结果表明,MB可以促进沉水植物V.spiralis的生长, V.spiralis可能通过根系分泌作用促进溶磷或是通过促进根际微生物群落的P代谢活性增加沉积物中的生物可利用性P含量.MB与沉水植物V.spiralis对沉积物P的联合作用效果优于MB和沉水植物V.spiralis单独作用之和.厚度5cm MB和V.spiralis联合作用对沉积物TP,IP,OP,Fe/Al-P和Ca-P的去除率可达59.8%,57.1%,67.8%,66.7%和44.7%.微生物试验结果表明,厚壁菌门Erysipelotrichaceae科的菌属PSB-M-3是联合组相比单一V.spiralis组或单一MB组微生物群落P代谢功能增强的主要贡献者.本研究还首次发现了Erysipelotrichaceae科微生物可作为沉积物中潜在的除磷菌.研究结果表明MB和沉水植物联合控制沉积物磷技术可进一步应用到富营养化湖泊沉积物控制工程.     

V2O5/CeO2催化剂用于低温NH3-SCR的性能研究

采用浸渍法制备了系列V2O5/CeO2催化剂,用于低温NH3选择性催化还原(NH3-SCR)NO.同时,考察了催化剂中V2O5负载量和煅烧温度对催化活性的影响,并运用SEM,BET和XRD物理化学技术对催化剂进行了表征.结果表明,V2O5/CeO2催化剂对模拟烟气中的NO转化呈现出较高的活性,但是V2O5负载量和催化剂的催化活性并不呈线性递增的关系.当V2O5负载量超过10%时,催化剂的催化活性开始下降.随着煅烧温度的升高,由于钒酸铈的生成,催化剂的催化活性下降.400℃为最佳煅烧温度.     

利用天然磁黄铁矿去除水中As (V)的研究

考察了时间、pH、温度、吸附剂投加量、无机阴离子等因素对磁黄铁矿去除As(V)过程的影响.同时,对去除过程的动力学和等温线进行分析,并探究了动态去除的效果.结果显示:磁黄铁矿对As(V)的去除在24 h达到平衡;在pH值3~9范围内去除率都达到80%以上;温度升高和吸附剂用量增加都对As(V)去除具有促进作用;PO_4~(3-)、SiO_3~(2-)、CO_3~(2-)对吸附有较强的抑制作用;在As(V)初始浓度为2 mg·L~(-1)时动态吸附出水浓度在150个吸附床体积(BV)内能达到国家饮用水标准;吸附去除过程符合拟二级动力学方程和Langmuir等温方程.能谱仪和X射线电子能谱分析表明,去除过程是一个自发吸热的配位离子交换反应.本实验表明,天然磁黄铁矿是一种有潜力的除砷吸附剂.     

养殖鳜鱼体内典型有机氯化合物的检测与人体健康风险评估初探

利用GC-ECD检测了江苏省吴江市某养殖塘内的一批鳜鱼体内有机氯农药（OCPs）和多氯联苯（PCBs）等典型有机氯化合物（OCs）的含量水平,并对其人体健康风险进行了初步评估.结果表明,养殖鳜鱼体内滴滴涕（DDTs）、六六六（HCHs）、六氯苯（HCB）和PCBs的含量范围分别为1.3～4.57、0.13～1.24、0...     

催化光度法测定环境样品中痕量钒的研究

研究了在磷酸介质中,利用高碘酸钾氧化罗丹明B测定环境样品中痕量钒的方法,最大吸收波长530nm,表观摩尔吸光系数2.71×10~8L·mol~(-1)·cm~(-1),在0～30ng/25mL范围内符合比耳定律,用于测定自来水和小麦中钒的含量,结果令人满意。