低频扩频中伪随机序列产生方法的研究

伪随机序列的产生是实现BPC低频时码发播台扩展频谱技术升级的一个重要环节。针对BPC低频时码发播台的现有系统，提出了伪随机序列的产生方案，并对其性能作了分析。     

IMPACTS OF FUTURE SEA LEVEL RISE ON SALT WATER INTRUSION IN THE CHANGJIANG RIVER ESTUARY

Sea level rise could increase the salinity of an estuary by altering the balance between fresh water and salt water. The implications of sea level rise for increasing salinity have been examined in the Changjiang (Yangtze) River estuary. By correlative analysis of chlorinity, discharge and tidal level and calculation of two-dimensional chlorinity, distribution of the Changjiang River estuary, the changes of the intensity and lasting hours of salt water intrusion at Wusong Station and the changes of chlorinity distribution in the South Branch of the Changjiang River estuary have been estimated when future sea level rises 50-100 cm. The intensity of salt water intrusion in the future will be far more serious than current trend.     

矢量数据栅格化的一种有效方法——环绕数法

矢量数据栅格化是GIS数据处理的一项重要任务。目前,已存在多种栅格化方法,但是每种方法都有各自的局限性。本文首次提出了环绕数法,它基于计算几何转角理论,通过计算跨越数来确定环绕数,是一种简单、高效、易于实现的栅格化方法。应用环绕数法,不但可以完成简单多边形的栅格化,而且可以完成自交多边形的栅格化。     

Strong Tides in 1964 and 1982

1StrongtideandastronomicalconditionsPartial solar eclipse occurred 4 times in 1964, 1982 and 2000 respectively. Time interval is about 3 Saros periods (one Saros period is 18 years and 10.33～11.33 days). Total lunar eclipse occurred 2 times in 1964 and 2000 respectively and 3 times in 1982. However, there was no lunar eclipse in 1966, 1984 and 2002. It seems that they had similar astro-nomical conditions and the best was in 1982. The studies about the effect of tide on the global climate…     

个性化大地测量报表服务的实现

报表服务是大地测量信息系统的一项基本功能，但往往会因为格式的微小调整而导致系统的整体重构。首先分析了当前报表生成方法的缺点，提出了基于XML相关技术生成报表的新思路；然后介绍了以XML为基本语法的统一数据交换接口，屏蔽了各种报表数据源的差异；重点讨论了如何运用XSL技术将接口文件变换成通用的HTML，并对报表中的图形信息用SVG进行描述，从而将报表转换成通用浏览器可以识别的信息模型；最后对此技术进行了实践。通过在系统外部更改报表样式文件，能够实现报表服务的个性化，增强系统的扩展性。     

HYDROLOGIC SERIES CHARACTERISTICSANALYSIS OF THE MAJOR RIVERS AROUNDTHE TAKLIMAKAN DESERT

I.IN~crIOXLocatedinthecoddlepatofTallmBasin,withanareaof33.76X104klnZ,theTaldirnakan~isinthehinterlandofEurasia.Blockedbythehighmountainsaround,vapourofoceancanhardlyreachthedesert.APartfromthis,asthedeSertisinthesinkingcompensationareaoftheascensionalaircurrentaamstheQinghal-XIZangPlateau,itSprecipitationisrareandtheevaporationcapacityisintensealltheyearround.Allthesecontributetotheformationsofthetypifydrydesertclimate.Theacidityindexofthedesertandthearoundregionisashighasmorethan50,w…     

信号流图求解部分分式展开

含有多重极点的有理真分式展开为部分分式，不需要计算低阶导数。列出被求函数的各阶导数的关系式，画出各阶导数作为节点的信号流图。该图无环路，既直观表现出各高阶导数的相互关系及影响的单向性，也使求节点增益的梅森公式特别简便。该方法将求高阶导数问题简化为代数运算，特别适合于编制成计算机程序     

Fatty Acid Composition Analyses of the DCMU Resistant Mutants of Nannochloropsis oculata (Eustigmatophyceae)

1　Introduction　Nannochloropsissp .areoneofpotentialsourcesofpolyunsaturatedfattyacids ,especiallytheeicosapen taentaenoicacid (EPA ,C2 0∶5 ) ,whichisimportantforbothanimalsandhumans .　Thefattyacidcompositionofthisalgaisaffectedbyvariousenvironmentalfactors ,suchaslightintensity(Sukeniketal.,1989;Sukeniketal.,1990 ) ,imply ingthatafactorinfluencingthephotosyntheticprocessmayaffectcellularfattyacidsynthesisandtheirmetabolism .AselectionprogramofincreasingcellularEPAcontenthasbeencarriedo…     

瞬变电磁法探测公路隧道工程中的不良地质构造

为了给公路设计部门提供选线依据,运用瞬变电磁法在山西境内的某两条高速公路隧道工程设计线路段上进行探测,以查明下覆不良地质构造的发育情况.通过对瞬变电磁法的探测能力进行理论上的讨论,对不同地电断面情况下的异常体电磁响应的定性分析,得出用瞬变电磁法探测不良地质体的可行性结论.经过资料处理,查出不良地质构造赋存的位置,解释结果与钻探资料完全吻合.     

The Kaidun meteorite: Clasts of alkaline‐rich fractionated materials

Abstract— Clasts of alkaline (the second find in meteorites) and subalkaline rocks were found in the Kaidun meteorite. One of them (#d4A) is a large crystal of albite with inclusions of fluorapatite, arfvedsonite, aenigmatite, and wilkinsonite. The two latter minerals were previously unknown in meteorites. Another clast (#d[3–5]D) has a melt crystallization texture of mainly feldspar (oligoclase) composition and contains relict grains of both high‐Ca and low‐Ca pyroxene and fluorapatite. The mineralogical characteristics of these clasts suggest a genetic relationship and an origin from the same parent body. The textural and mineralogical characteristics of the clasts indicate origin by extensive igneous differentiation. Such processes most likely took place in a rather large differentiated body. The material of clast #d(3–5)D is similar in some mineralogical respects to basaltic shergottites.