两交替运行部件冷贮备可修系统的可靠性

考虑一个两个交替运行部件冷储备系统的可靠性,系统每过T时间部件交替运行一次,部件的寿命和维修时间服从一般分布,所有随机变量相互独立,利用马尔科夫更新过程方法以及L-S变换工具,得到了系统主要可靠性指标的拉普拉斯变换表达式,系统的平均首次故障前时间,系统的稳态可用度,系统的稳态平均故障频度。     

深埋超大断面单拱隧道开挖有限元分析

以铁路某地下超大断面单拱隧道的2种施工方案为研究对象,该单拱超大跨隧道跨度达41.10m,高度达22.50m,开挖面积829.1573m2,属于极少见的超大跨单拱隧道,在其开挖前先进行有限元分析,分别从开挖稳定性、锚杆轴力、初衬受力和围岩变形等4方面对特大跨隧道的开挖方案修建技术进行了分析和讨论,得出一些有益的结论,可为今后类似工程提供参考。     

DETECTION OF STRAND BREAKS OF DNA IN HUMAN EARLY CHORIONIC VILLUS CELLS INDUCED BY DIAGNOSTIC ULTRASOUND USING ^32P-LABELED ALU HYBRIDIZATION

Genetic effects of ultrasound on fetus havebeen extensively studied since ultrasonograph waswidely appliedin obstetric practice.In recent years,there have been reports onin vivomolecular geneticeffects of diagnostic ultrasound[1-4].In vitroexperi-ments have found that single-stranded breaks(ssbs)and double-stranded breaks(dsbs)in DNA are themain indices for DNA lesions induced by ultra-sound[5].But,no reports on whether ultrasound cancausein vivossbs and dsbs in DNAare available.Tofurther …     

关于水泥混凝土路面施工工艺的讨论

工程一般采用用槽钢模板，高22cm，每节长4m。支立模板时，根据设计预先放出的中线及路面边线将模板就位，固定模板时用预制好的混凝土块。或特制支架压牢为好。如用钢钎固定时，则不准直接打入基层中，可用冲击或旋转钻造孔打入，防止基层震裂。     

A NEW METHOD TO CONSTRUCT A FULL-LENGTH cDNA LIBRARY OF HUMAN NORMAL BLADDER TISSUE

ThepurposeoftheHumanGenomeProjectistounravelthe geneticinstructionsencodedbygenes.Identificationof protein codingandfunc tionalsequenceswithin genomeDNAcomplementthephysicalandgeneticmappingwork ,whichlaysfoundationforfurtherresearchintocomplexphe nomenaofgrowth ,development,differentiation ,carcinogenesis,etc.ThesearchforgenesresponsibleforhumandiseasesandbiologicalfeaturesandthestudiesoftheirstructuresandfunctionsrelyontheavailabilityofhighfidelitycDNAlibrariesfromvariouscelltypesandtissu…     

浅谈全球定位系统(GPS)在高速公路测量中的应用

1 GPS测量特点 (1)测站之间无需通视. (2)定位精度高. (3)观测时间短. (4)提供三维坐标. (5)操作简便. (6)全天候作业.     

MICROARRAY ANALYSIS OF DIFFERENT GENE EXPRESSION OF HUMAN CERVICAL CANCER SUBCLONE CELL LINES

Objective To examine the differentially expressed invasion-related genes in two anchorage-independent uterine cervical carcinoma cell lines derived from the same patient using a cDNA array. Methods Two human uterine cervical carcinoma subclonal cell lines CS03 and CS07 derived from a single donor line CS1213 were established by limited dilution procedure. The two cDNA samples retro-transcribed from total RNA derived from CS03 and CS07 cells were screened by a cDNA microarray carrying 234 human cell-cycle related genes and 1011 human signal transduction and membrane receptor -associated genes, scanned with a ScanArray 3000 laser scanner. Results The cDNA microarray analysis showed that ]2 genes in CS03 were up-regulated compared to CS07, and 24 genes in CS07 were upregulated. The function of a number of differentially expressed genes was consistently associated with cell-cycle, cell proliferation, migration, apoptusis, signal transduction and tumor metastasis, including p34^cdc2, TSC22, plasminogen activator inhibitor Ⅰ （PAI-1）and desmusome associated protein（Pinin）. Conclusion Multiple genes are differentially expressed in uterine cervical carcinoma cell lines even came from the same patient. It is suggested that these genes are involved in the different phenotypic characteristics and development of cervical carcinoma.     

RLC－310人体肾透明细胞癌细胞株的生物学和形态学特点

对新建的克隆性人肾透明细胞癌细胞株ＲＬＣ－３１０进行了生物学鉴定和形态学观察。发现细胞可重叠生长，群体倍增时间３２ｈ，集落形成率４４％，具有超二倍体核型，染色体众数６４。细胞没有支原体污染，有特异性的ＬＤＨ同功酶谱，细胞接种Ｂａｌｂ／ｃ裸鼠可形成移植瘤。细胞大小均一，核大，细胞表面有丰富的微绒毛，未见到细胞间的桥粒结构。胞质内有变形的粗面内质网、线粒体和较多糖原颗粒，张力原纤维可见。细胞核异形性明显，核仁数目增多，有边集。表明这株细胞保持了肾透明细胞癌的基本特点。     

北方国际集装箱运价指数走势分析(2021年2月)

2021年2月,因春节假期调休,天津航运指数下设的北方国际集装箱运价指数共发布17次:假期前,指数基本稳定;假期后,指数大幅震荡(见图1).2月1日,欧洲和南非航线运价小幅下滑,地西和南美东航线运价上涨,其他航线运价保持平稳,北方国际集装箱运价指数微跌0.16％.2月2-10日,南美东航线运价略有下跌,韩国仁川航线运价微涨,其他航线运价稳定,北方国际集装箱运价指数稳中微升,累计上涨0.11％.2月18--26日,欧洲、美国、南美和南非航线运价整体下行,地东航线运价稳中有涨,地西、韩国釜山和韩国仁川航线运价大幅攀升,北方国际集装箱运价指数快速冲高后波动走弱,累计上涨0.16％.2月26日,北方国际集装箱运价指数收于1 866.27点,比1月29日上涨2.02点,涨幅为0.11％.