"word"、"词"和"字"

“word”、“词”和“字”是英汉语中的三个基本概念。对比“word”与“词”、“word”与“字”,探讨它们的对应性和非对应性,揭示这些对应性和非对应性存在的原因,对于廓清概念及汉语和汉英对比研究都颇具意义。     

"空巢"不"空"

"空巢"(EmptyNest),是近些年出现的一个新名词,很多人认为这个词语只可意会不能言传.那么,究竟什么是"空巢"呢?单从字义上讲, "空巢"就是"空寂的巢穴",比喻小鸟离巢后的情景,现在被引申为子女长大成人后离开父母,只剩下上一代人单独生活的家庭.     

"过错"莫"错过"

在预防事故工作中,有些事情看起来微不足道,实际上非同小可。有的小事捅出大娄子,懊悔不已;有的无视安全,酿成大祸;有的违章操作,命丧黄泉。     

"孝"对"死刑"

“百善孝为先”,孝乃中华民族文化精神大义,中国文化倡扬行孝,乃至对孝子之罪法外开恩；“不孝”乃元恶,“五刑之属三千,而罪莫大于不孝”。“孝”与“不孝”孰是孰非?人人行孝则天下自平；人人不孝却国将不国!     

解"立"——从"三十而立"到"安身立命"

孔子所说的“三十而立”中的“立”不是指成家立业,而是在对社会和自己都有比较明确的认识和理解的基础上的一种自觉的或者是有相对觉解的意识,一种自我人格独立的意识。人的“立”意识是一种普遍的精神现象,具有自觉性、独立性、阶段性、过程性、内在和外在统一性等特征。在对生命之“立”反思意识有所忽视和遗忘的今天,我们应清醒地认识到“立命”才能真正安身,承担崇高的人生使命、培养高尚的道德情操,投身于国家和社会的建设中,我们的人生才有意义。     

试析"偏"与"偏偏"

对语气副词"偏"、"偏偏"从句法、语义、语用三个角度进行考察,揭示二者的相同点和不同点,以便全面、准确地把握二者的用法.     

从"食品卫生"到"食品安全"

在两起"奶粉事件"——从2004年的阜阳奶粉事件到2008年的三鹿奶粉事件面前——《中华人民共和国食品卫生法》显得那么无助和苍白无力,或许没有几部法律像《食品安全     

"温室效应"与"氧气枯竭"

“温室效应”对人类的首位的最大危害并非全球气候变暖问题,而是对全球人类基本生存条件造成破坏的大气“氧气枯竭”问题,“氧气枯竭”最终会导致人类灭绝的最为严重的后果.     

从"同一性"到"多样性"

人类遗传多样性是生物多样性的重要组成部分。遗传多样性是指生物基因组在长期进化过程中积累起来的遗传变异。这些变异可以是有益的、中性的或有害的;其中一些被保存下来,导致不同种族、群体和个体间基因组的差异,那就是遗传多态性。人类遗传多样性寓于世界民族和各遗     

运输项目风险分析与评价研究

针对在运输项目中,不确定性和风险因素普遍存在的特点,提出了风险评价的基本概念,从不确定性出发,对项目评价指标中相关的中以分析,在净现指标指标评价中,给出了净现值指标期望值和方差的一种新算法,并引用了风险分析和效用分析相结合的方法,从面蚵获得运输项目比较满意的评价结果。     

TiO_2封装对铁基纳米晶磁芯软磁性能的影响

以钛酸四丁酯为前驱体,二乙醇胺为抑制剂,采用溶胶-凝胶法制备TiO_2溶胶,再用浸渍提拉法在Fe_(73.5)Cu_1Nb_3Si_(13.5)B_9纳米晶磁芯表面制备TiO_2涂层,研究了TiO_2封装对纳米晶磁芯软磁性能的影响。结果表明,与TiO_2封装前相比,TiO_2封装后纳米晶磁芯的初始磁导率μ_i、最大磁导率μ_m、饱和磁感应强度B_s、电感L_s、品质因数Q和感应电动势E减小;剩磁B_r、磁滞损耗P_u和矫顽力H_c增大。     

厚朴叶与厚朴皮、厚朴花的毒性比较研究

目的研究厚朴叶的毒性及与厚朴皮、厚朴花的毒性比较,为厚朴叶的开发利用提供实验依据。方法通过急性毒性实验,小鼠骨髓微核实验,小鼠精子畸形实验,大鼠30 d喂养实验,来研究厚朴叶毒性和进行毒性比较。结果在急性毒性实验中,各给药组小鼠无死亡;小鼠骨髓微核实验中和精子畸形实验中,各给药组与正常组无统计学差异。大鼠30 d喂养实验中,厚朴叶对大鼠的食物利用率、血常规、肾功能都有所影响,也影响肝、卵巢、睾丸的脏体系数;在对大鼠各脏器病理组织学检查中未见明显异常;厚朴叶与厚朴皮、厚朴花的慢性毒性差异为后两者不影响血常规。结论厚朴叶无急性毒性,无致骨髓突变毒性,无致精子畸形毒性;厚朴叶有慢性毒性作用,表现在影响食物利用率、血常规、肾功能、器官发育;厚朴叶与厚朴皮、厚朴花的毒性差异表现在慢性毒性中影响血常规,其它无差异。     

Agrobacterium tumefaciens-mediated Transformation of CryⅠA(b) gene to Trichoderma harzianum

In this study, Cry ⅠA(b) gene was successfully transferred into the biocontrol fungus Trichoderma harzianum with an efficiency of 60-180 transformants per 10^6 spores by using Agrobacterium tumefaciens-mediated transformation. Putative transformants were analyzed to test the presence of Cry ⅠA(b) gene by Southern blot. Most transformants contained a single T-DNA copy. RT-PCR analysis showed that the Cry ⅠA(b) gene was transcribed. Antifungal activities and insecticidal activities of the transformants were examined. There was no obvious difference in antifungal activities between the transformants and their wild strains. The modified mortalities of the transformants T1 and T2 were 69.57% and 91.30%, respectively. The tranformation system mediated by A. tumefaciens proved to be a powerful tool for the filamentous fungi transformation and functional genomic study with its high transformation frequency, simplicity of T-DNA integration, and genetic stability of transformants.     

微量镍元素添加对铁基非晶/纳米晶磁芯软磁性能的影响

用单辊法制备的宽20 mm,厚25μm的Fe_(73.5)Cu_1Nb_3Si_(13.5)B_9和Fe_(73.5)Ni_(0.3)Cu_1Nb_3Si_(14.2)B_8合金带材,绕制成外径为40 mm,内径为25 mm的环型磁芯,然后将磁芯在不同的温度下进行退火处理,研究了微量Ni元素添加对合金带材的晶化行为以及对横向磁场退火后的非晶/纳米晶磁芯的软磁性能的影响。结果表明:与Fe_(73.5)Cu_1Nb_3Si_(13.5)B_9合金带材相比,添加微量Ni元素的Fe_(73.5)Ni_(0.3)Cu_1Nb_3Si_(14.2)B_8合金带材的一级起始晶化温度Tx1和一级晶化峰温度Tp1降低,其二级起始晶化温度Tx2和二级晶化峰温度Tp2升高,两级起始晶化温度之间的差值ΔTx增大;与横向磁场退火后的Fe_(73.5)Cu_1Nb_3Si_(13.5)B_9非晶/纳米晶磁芯相比,横向磁场退火后的Fe_(73.5)Ni_(0.3)Cu_1Nb_3Si_(14.2)B_8非晶/纳米晶磁芯的起始磁导率μi和饱和磁感应强度Bs减小,矫顽力Hc增大;当测试频率f和最大磁感应强度Bm不变时,有效幅值磁导率μa增大,比总损耗Ps和矫顽力Hc减小;当测试频率f不变时,电感Ls和品质因数Q增大;当励磁电流I不变时,感应电动势E大。     

完全图Kn的{P5,C5}分解

图分解问题已在很多邻域中得到了广泛的应用。用P₅表示5个顶点的路，C₅表示5个顶点的圈，本研究讨论了完全图K_n分解成5个顶点的路P₅和圈C₅的存在性，给出完全图K_n存在{P₅,C₅}-强制分解的充分必要条件是n≥7(n≠8)，以及完全图K_n存在{P₅,C₅}-分解的充分必要条件是n≥5(n≠6)。     

Reporter-based screen for <Emphasis Type="Italic">Arabidopsis</Emphasis> mutants compromised in nonhost resistance

Plants are exposed to many potentially pathogenic microbes in the environment, but each species is only susceptible to a limited number of pathogens. The broad resistance is referred to as nonhost resistance. To date, little is known about the underlying mechanism of nonhost resistance and the signaling transduction process. Here we describe a simple method for isolating Arabidopsis nonhost resistance mutants against a nonadapted bacterial pathogen. A RAP2.6 promoter-driven LUC reporter system was developed to replace the tedious bacterial growth assay during the primary screening. The RAP2.6-LUC reporter gene is normally induced by the virulent bacterium Pseudomonas syringae pv tomato but not the nonadapted bacterium P. syringae pv phaseolicola. By using this method we iso- lated 4 mutants displaying strong reporter activity in response to P. syringae pv phaseolicola, which were characterized in some details, ebsl, ebs2, ebs3, and ebs4 （enhanced bacterial susceptibility） were compromised in resistance against P. syringae pv phaseolicola and/or P. syringae pv tomato. In addition, ebs4 showed enhanced hypersensitive response to the incompatible bacterium P. syringae pv tomato （avrB）. These results demonstrated that the method is suited for large scale screening for nonhost resistance mutants.     

Ubi1 intron-mediated enhancement of the expression of Bt cry1Ah gene in transgenic maize （Zea mays L.）

The cry1Ah gene was one of novel insecticidal genes cloned from Bacillus thuringiensis isolate BT8. Two plant expression vectors containing cry1Ah gene were constructed. The first intron of maize ubiqutinl gene was inserted between the maize Ubiquitin promoter and cry1Ah gene in one of the plant expressing vectors （pUUOAH）. The two vectors were introduced into maize immature embryonic calli by microprojectile bombardment, and the reproductively plants were acquired. PCR and Southern blot analysis showed that foreign genes had been integrated into maize genome and inherited to the next generation stably. The ELISA assay to T1 and T2 generation plants showed that the expression of CrylAh protein in the construct containing the ubil intron （pUUOAH） was 20% higher than that of the intronless construct （pUOAH）. Bioassay results showed that the transgenic maize harboring cry1Ah gene had high resistance to the Asian corn borers and the insecticidal activity of the transgenic maize containing the ubil intron was higher than that of the intronless construct. These results indicated that the maize ubil intron can enhance the expression of the Bt cry1Ah gene in transgenic maize efficiently     

菊粉内切酶在毕赤酵母中的表达及酶学性质测定

为了实现菊粉内切酶在毕赤酵母(Pichia pastoris)中的高活性表达并对表达的菊粉内切酶酶学性质、水解菊粉的产物进行分析。通过下载无花果曲霉菊粉内切酶基因的编码序列,做了密码子优化后进行全基因合成,然后在毕赤酵母GS115中表达。对表达的菊粉内切酶的酶活、最适反应温度、最适pH值、热稳定性进行了分析,最后对酶水解菊粉的产物进行了高效液相色谱(HPLC)分析。摇瓶表达的酶活力为420 U/mL,酶的最适反应温度为55℃,最适反应pH为6.0。HPLC分析表明:表达的菊粉内切酶酶解底物菊粉的主要产物为低聚果糖,聚合度为3～5之间。构建的工程酵母可以高效表达菊粉内切酶,可以用于生产低聚果糖。     

黄芩中黄芩新素提取制备工艺优化的研究

目的 为建立制备大量高纯度黄芩新素的方法。方法 比较了超声法和回流提取法提取黄芩中黄芩新素,及不同萃取溶剂对黄芩中黄芩新素得率的影响,通过HPLC色谱法测定黄芩新素的含量,并用LC-8A高压制备色谱仪制备黄芩新素。结果 采用回流提取法及使用乙醚作为萃取溶剂时,黄芩新素得率最高,制备的黄芩新素纯度可达到97.96%。结论 本实验建立的方法操作简便,重现性好,制备的黄芩新素纯度符合对照品纯度的要求。