浅谈高中英语教学效果的提高——从教学内容上进行分析

随着新课标的推出,对高中英语教学提出了综合发展学生英语语言能力的要求。本文结合教学内容,从提高高中英语教学效果出发,在听力、口语、词汇、阅读、写作等五个方面进行了分析阐述。     

基于机动车排放的自适应信号控制模型

从减少交叉口机动车排放量的角度,分析了信号控制对机动车排放影响因素的作用机理,阐述了信号配时-行驶工况-机动车排放三者之间的关系;根据机动车行驶工况变化对排放的影响,建立了车辆完全停车、不完全停车以及不停车3种状态下的机动车排放计算模型;以交叉口车均排放增加量最小为优化目标,确定了信号配时方案的优化方法.以长春市某典型...     

Establishment and cryopreservation of liver, heart and muscle cell lines derived from the Chinese alligator （Alligator sinensis）

The Chinese alligator, Alligator sinensis, is a critically endangered species. A conservation project of gene resources for an endangered species first involves the preservation of organs, tissues, gametes, genomic DNA libraries and cell lines. The present study is the first to establish and cryopreserve cell lines of liver, heart and muscle tissues from the Chinese alligator. The study revealed that there was a large discrepancy in cell migration time in primary cultures among liver (11-12 d), heart (13-14 d) and muscle (17-18 d) tissue pieces. The differences in time in primary cell culture suggested that it was relatively easy to build visceral-derived cell lines for reptiles. Biological analysis showed that the population doubling time for thawed cells was approxi- mately 36 h. Karyotyping revealed that the frequency of Chinese alligator cells showing chromosome number as 2n=32 was 88.6%-93.4%. Chinese alligator cell lines established here provide a vital resource for research and are likely to be useful for protection of this rare and critically endangered species. Furthermore, the establishment of these methods may supply technical and theoretical support for preserving genetic resources at the cellular level for other reptile species.     

Experimental study on the explosive boiling in saturated liquid nitrogen

Nowadays,thedevelopmentandapplicationofsuperconductionisbecomingmoreandmoreimpor tantinmanyareas .Duringtheworkingprocessofsu perconductor,somefactors ,forinstance ,deforma tion ,friction ,andmagneticvortex ,canresultinin stantaneousandrandomheatimpulsion ,andmakeitover heatedtothecriticaltemperatureanddeviatefromthenormaloperationcondition .Undersomeex tremeconditions ,thesuperconductorcannotgobacktothenormalstateevenifremovingthetransientheat load ,thusverysevereandunexpectableconse quencema…     

Crystallization and preliminary X-ray diffraction analysis of FKBP12 complexed with a new neurotrophic ligand

Thetherapyofnerveinjuryandneurode generativediseasessuchasAlzheimer’sdiseaseandParkinson’sdiseaseisadifficultprojectforscientiststosurmount.Manydrugsandtherapeuticapproacheshavebeenusedtotreatthesediseases ,buttheresultisunsatisfactory[1] .Inrecent years ,neurotrophinsincludingnervegrowthfactor (NGF) ,neurotrophin3(NT3) ,neurotrophin 4 / 5 (NT4 / 5 )andbrain de rivedneurotrophicfactor (BDNF)werestudiedex tensivelyandfoundtoaffectthesurvival,growth ,and/ordifferentiationofneuronsandsever…     

Hausdorff centered measure of certain linear Cantor sets

Thenotionofpackingmeasure ,introducedinRefs.[1— 3],hasbeenusedincomparisonwithHausdorffmeasuretostudytheregularityandrectifi abilityofsetsintheplane[4 ] .TheHausdorffmeasureisdefinedusingeconomicalcoversofaset,whilethepackingmeasureisdefinedviapackingwithdisjointballscenteredinthegivenset (formoredetailsseeRefs .[5— 7]) .Asasymmetryofthepackingmea sure ,theHausdorffcenteredmeasure ,definedbythecoverswithballscenteredinthegivenset,wasintro ducedinRef .[4 ].RaymondandTricot[8] verifiedthatt…     

利用物理诱变活性污泥深度处理焦化废水的研究

采用紫外线、变温和超声波等物理诱变方法,对SBR工艺处理焦化废水中的活性污泥进行了诱变处理,将诱变后的污泥用于二级生化处理出水的后续处理,比较了处理前后焦化废水中CODcr、NH3-N和TOC的变化,并使用GC-MS方法分别对处理前后焦化废水中有机物的降解情况进行了分析.结果表明,经诱变处理后的活性污泥对焦化废水中剩余CODcr、NH3-N、TOC和难降解有机物的降解能力有所增加；在三种物理诱变方法中,超声波与变温处理对微生物的诱变效果较好,紫外线较差.     

别让老鼠目睹人类灭绝——世界环境日感怀

假如地球只有人类?我真的不敢想象那是什么样子. 帮朋友策划出版《灭绝之路(野生动物保护手册)》一书之后,我几乎每年的"6·5"世界环境日都去造访地处京城的世界灭绝动物墓地. 这是一处美丽幽静的湿地河谷,像香港沙田的跑马场,放眼望去,绿草青青,池塘和老树一明一暗,点缀着麋鹿悠闲的身影.这片湿地河谷长久被我们遗忘了,它曾是元、明、清三代皇家苑囿;更鲜为人知的是,清朝末年,世界上最后一群麋鹿曾保存在这里,当时并不为人们所知.     

单圈连通图的边独立指数

依据图的边独立指数概念,探讨了单圈连通图的边独立指数的相关性质,得到了单圈连通图边独立指数的上、下界,并给出了单圈连通图边独立指数达到上、下界的极图     

不同氮水平处理对金银木苗木的生理影响

以两年生金银木为样本,在苗木生长的萌芽期、生长初期、速生期和硬化期对其进行不同施氮量处理,测定它们对金银木生理生化指标的影响,基于试验结果,指出N4处理能有效地提高金银木苗木叶片中SOD与POD酶活性,氮水平太低时效果不明显,过高则会造成浪费并抑制苗木生长。