ELECTRONIC CONTROL OF TURBINE POWER UNITS

ＥＬＥＣＴＲＯＮＩＣＣＯＮＴＲＯＬＯＦＴＵＲＢＩＮＥＰＯＷＥＲＵＮＩＴＳ￥ＷａｎｇＤａｏｂｏ（ＤｅｐａｒｔｍｅｎｔｏｆＳｃｉｅｎｃｅａｎｄＴｅｃｈｎｏｌｏｇｙ，ＮＵＡＡ２９ＹｕｄａｏＳｔｒｅｅｔ，Ｎａｎｊｉｎｇ２１００１６，Ｐ．Ｒ．Ｃｈｉｎａ）Ａｂｓ...     

考古,寻找进化的雕塑——对话罗伯特·巴克（下）

斯：你不仅是知名的古生物学家，而且是一位有造诣的艺术家。你是怎样学习绘画的？ 巴：任何人都能作画。绘画的能力不在你的指尖，而在你的眼睛里。如果你能看见结构，如果你能看见形式，你就能把它记录下来。我上解剖学课，就把学生带到动物园，对他们说：“画那头美洲豹。”“我不会画。”他们说。“你们能看见那头美洲豹吗？”“能看见。”“肘部是直的还是弯的？“‘噢，弯的”“踝关节是弯的吗？”“是的。”“它比狗的踝关节还要弯吧？”“不错。”“把它画下来。”要是你懂得怎样看结构，能在你的头脑中大概画下一系列东西，你就能把它画到纸上。     

考古，寻找进化的雕塑——对话罗伯特·巴克（上）

达林·R．斯蒂尔（以下简称“斯”）：你刚上四年级的时候就决定研究恐龙。是受到什么影响吗？     

具有无源控制空腔时正激波/湍流附面层干扰的数值模拟

采用雷诺平均N-S方程和B/L代数湍流模型计算了具有无源控制空腔时正激波/湍流附面层干扰流场。计算与实验结果的比较表明,本文方法可较准确地预测激波结构、激波与附面层干扰区流动基本特征及波后流动分离状态、激波位置、波前马赫数等参数。      

湿热对单向复合材料层合板Ⅱ型分层特性的影响

利用横向裂纹拉伸试验模型（Transverse Crack Tension-tension Test）,在3种湿热环境（室温、85℃和85℃/95%RH）条件下,对2种单向碳纤维增强树脂基复合材料（T300/QY8911和HTA/6376）层合板的Ⅱ型分层特性进行了试验研究。结果表明湿热环境导致复合材料层间断裂韧性降低,引起Ⅱ型应变能释放率门槛值显着下降,裂纹扩展速率大大提高,温度的影响较湿度更为明显。利用电镜（SEM）对试样分层表面进行了检测,湿度对断面特征无明显的影响。     

铂电阻温度计在13.81—273.15K之间的内插方法

前言根据1968年国际实用温标(1975年修订版),在13.18—273.15K之间检定铂电阻温度计,是在若干个定义固定点上对铂电     

CONSTRUCTIONOFACLASSOFPNSEQUENCESWITHPRIMENUMBERPERIODSOF4t＋1FORM

构造了一类４ｔ＋１型质数周期的伪随机序列。该序列提供了比ｍ（Ｍ）序列更多的可供选择周期数，同时证明了它具有良好的伪随机特性     

在电解高纯石英谐振器中辐照引起的频率和电阻的变化

本文描述了由电解高纯石英制造的高精密5兆赫AT切石英谐振器中辐照引起的频率和电阻的变化。文中介绍了辐照测量方法、瞬态和稳态数据,以及热模拟结果。依嗦尔研究成果中的光学级和超Q石英可以像生长的晶体一样足够纯,得出的结论是:1)没有观察到通常与频率时间相关的t~(-1/2)恢复特性;2)如果未经电解,杂质含量仍然很高,足以在离子辐照脉冲后的一个短时间内使品质因数明显下降;3)由于电解能够进一步降低辐照响应,所以,杂质的影响不再很明显;4)电解石英的瞬时辐照响应实际上主要是热造成的。     

MMS星座对磁层顶磁通量绳内离子惯性尺度结构的观测

利用MMS观测数据,对磁层顶通量绳内离子惯性尺度（d_i）的结构进行分析研究.结果发现,许多不同尺度（约1d_i至数十d_i）的通量绳内都存在具有d_i尺度的电流 j _m,其方向在磁层顶局地坐标系的-M方向,即与磁层顶查普曼-费拉罗电流同向,由电子在+M方向的运动（ v _em）携带.这些电流结构具有以下特征:磁鞘与磁层成分混合,磁场为开放形态;离子去磁化,电子与磁场冻结;N方向（即垂直于磁层顶电流片方向）的电场 E _n显著增大,幅度达到约20mV·m-1,并伴有明显的尖峰状起伏,该增强和尖峰状起伏的电场对应于霍尔电场.分析表明,电流、电子与离子运动的偏离以及霍尔电场之间遵从广义欧姆定律,三者密切关联.进一步对磁层顶磁重联的探测数据进行分析发现,在很多重联区内也存在与通量绳内相似的结构,其尺度约为d_i量级,其中霍尔电场 E _N、电流 j _M和电子速度 v _eM均与通量绳内对应物理量的方向相同且幅度相近.基于上述观测事实,采用经典FTE通量绳模型,对通量绳内电流、电子运动和霍尔电场的起源进行了初步探讨,认为其来源于磁层顶无碰撞磁重联区内的相应结构,并且后者在离子尺度通量绳的形成过程中起到重要作用.      

Microbially induced iron precipitation associated with a neutrophilic spring at Borra Caves, Vishakhapatnam, India

The present investigation uncovers various pieces of evidence for the possible biologically induced mineralization in iron mats associated with a pH-neutral spring in the Borra caves, Vishakhapatnam, India. Electron microscopy [scanning electron microscopy (SEM) and transmission electron microscopy (TEM)] demonstrated large numbers of (i) hollow tubes (diameter ～1?μm) resembling sheaths of the iron-oxidizing bacteria Leptothrix, (ii) thin (diameter <1?μm) solid fibers of uncertain origin, (iii) nanoscale subspherical to irregularly shaped particles encrusting tubes and fibers, and (iv) aggregates of broken and partially disintegrated sheaths, fibers, and particles embedded in extracellular polymeric substances (EPS) occasionally including microbial cells. X-ray microanalyses by energy dispersive spectroscopy (EDS) revealed that the mat accumulated largely Fe but also smaller amounts of Si and traces of P and Ca. Particles rich in Si and Al (possibly kaolinite) and Ca (carbonate) were also observed. High-resolution TEM/EDS of unstained ultrathin sections suggests that microbial sheaths were highly mineralized by amorphous to cryptocrystalline Fe-rich phases and less frequently by other fine-grained and fibrous authigenic claylike minerals. Total number of microorganisms in the iron mats was 5.8×10(5) cells, g sed(-1) (wet weight). Analysis of the 16S rRNA gene diversity revealed microorganisms assigned to eight different phyla [Proteobacteria (62%), Chloroflexi (8%), Bacteroidetes (7%), Planctomycetes (1%), Actinobacteria (5%), Acidobacteria (6%), Nitrospira (1%), Firmicutes (5%)]. Within the Proteobacteria, Betaproteobacteria was the predominant class, which accounted for 28% of the sequences. Within this class some obvious similarities between the obtained sequences and sequences from other cave systems could be seen, especially sequences affiliated with Leptothrix, Siderooxidans, Crenothrix, Comamonadaceae, Dechloromonas, and many uncultured Betaproteobacteria. Four (4%) of the sequences could not be assigned to phylum level but were affiliating with the candidate division TM7 (2%), candidate division OP11 (1%), and candidate division WWE3 (1%). The results allow us to infer a possible relationship of microbial sheaths, EPS, and the iron precipitates to microbial community diversity in the Borra cave springs. Understanding biogenic iron oxides in caves has important astrobiological applications as it provides a potential tool for the detection of extraterrestrial life.