低频振荡中系统总阻尼的探讨

介绍了系统总阻尼的概念,对低频振荡中系统总阻尼进行了数学推导,分析了与系统阻尼有关的参数及如何通过调整某些参数达到使系统总阻尼增加,且不会造成其他振荡模式阻尼的减小。通过电力系统分析综合程序(PSASP)仿真计算进行了验证。     

Insight into the Impact of Oxidative Stress on the Barrier Properties of Lipid Bilayer Models

As a new field of oxidative stress-based therapy, cold physical plasma is a promising tool for several biomedical applications due to its potential to create a broad diversity of reactive oxygen and nitrogen species (RONS). Although proposed, the impact of plasma-derived RONS on the cell membrane lipids and properties is not fully understood. For this purpose, the changes in the lipid bilayer functionality under oxidative stress generated by an argon plasma jet (kINPen) were investigated by electrochemical techniques. In addition, liquid chromatography-tandem mass spectrometry was employed to analyze the plasma-induced modifications on the model lipids. Various asymmetric bilayers mimicking the structure and properties of the erythrocyte cell membrane were transferred onto a gold electrode surface by Langmuir-Blodgett/Langmuir-Schaefer deposition techniques. A strong impact of cholesterol on membrane permeabilization by plasma-derived species was revealed. Moreover, the maintenance of the barrier properties is influenced by the chemical composition of the head group. Mainly the head group size and its hydrogen bonding capacities are relevant, and phosphatidylcholines are significantly more susceptible than phosphatidylserines and other lipid classes, underlining the high relevance of this lipid class in membrane dynamics and cell physiology.     

曝气生物滤池去除受污染饮用水源水中的氨氮

采用曝气生物滤池(BAF)对受污染水源水进行了除氨氮效果研究,结果表明,当原水氨氮质量浓度在0.240～1.407 mg/L范围内时,氨氮平均去除率为83%,进水氨氮的质量浓度人工增加至O.717～12.455 mg/L时,氨氮平均去除率为88%,具有较好的氨氮去除效率和抗冲击负荷能力;同时探讨了进水氨氮容积负荷对氨氮去除效果的影响.     

Molecular Identification of the G-Protein Genes and Their Expression Profiles in Response to Nitrogen Deprivation in Brassica napus

Heterotrimeric guanine nucleotide binding protein (G-protein) consisting of Gα, Gβ, and Gγ subunits is one of the key signal transducers in plants. Recent studies indicated that G-protein has been proposed as an important mediator of nitrogen responses in rice, wheat, and Arabidopsis. However, little is known about these G-proteins in Brassica napus (B. napus), except for three identified G-proteins, BnGA1, BnGB1, and BnGG2. Therefore, the aim of the present study is to characterize the members of the G-protein gene family in allotetraploid B. napus and to analyze their expression profiles in response to nitrogen deprivation. In total, 21 G-protein family members were identified in B. napus, encoding two Gα, six Gβ, and 13 Gγ. Sequence and phylogenetic analyses showed that although genome-wide triploid events increased the number of genes encoding Gα, Gβ, and Gγ subunits, the gene structure and protein properties of the genes encoding each G-protein subunit were extremely conserved. Collinearity analysis showed that most G-protein genes in B. napus had syntenic relationships with G-protein members of Arabidopsis, Brassica rape (B. rapa), and Brassica oleracea (B. oleracea). Expression profile analysis indicated that Gα and C-type Gγ genes (except BnGG10 and BnGG12 were highly expressed in flower and ovule) were barely expressed in most organs, whereas most Gβ and A-type Gγ genes tended to be highly expressed in most organs. G-protein genes also showed various expression patterns in response to nitrogen-deficient conditions. Under nitrogen deficiency, Gα and five C-type Gγ genes were upregulated initially in roots, while in leaves, Gα was downregulated initially and five C-type Gγ genes were highly expressed in different times. These results provide a complex genetic dissection of G-protein genes in B. napus, and insight into the biological functions of G-protein genes in response to nitrogen deficiency.     

氮在Fe-Cr-V液态高氮合金中的溶解行为

 采用MgO坩埚高频真空/加压感应炉在氮气压力04~10 MPa、温度1 570~1 640 ℃下,对加压感应熔炼Fe Cr V系高氮不锈钢进行了实验研究。结果表明,在30CaO 45Al2O3 25SiO2渣覆盖的情况下,氮在Fe 15Cr 10V、Fe 18Cr 10V、Fe 18Cr 15V和Fe 20Cr 20V液态合金中的溶解度分别为0595%、0736%、0776%和1020%,溶解度与氮分压的关系基本符合Sievert定律。渣对钢液吸氮和铝脱氧都起重要的作用,1 873 K、10 MPa氮气氛中,在30CaO 45Al2O3 25SiO2、40CaO 40Al2O3 20SiO2、40CaO 50Al2O3 10SiO2三种不同渣系作用下氮在液态Fe 18Cr 15V中的浓度分别是0776%、0849%和0884%。     

Genome-Wide Identification of TaSAUR Gene Family Members in Hexaploid Wheat and Functional Characterization of TaSAUR66-5B in Improving Nitrogen Use Efficiency

Excessive input of nitrogen fertilizer not only causes a great waste of resources but brings about a series of ecological and environmental problems. Although Small Auxin Up-regulated RNAs (SAURs) participate in diverse biological processes, the function of SAURs in the nitrogen starvation response has not been well-studied. Here, we identified 308 TaSAURs in wheat and divided them into 10 subfamilies. The promoter regions of most TaSAURs contain hormone responsive elements, and their expression levels change under the treatment of different hormones, such as IAA, MeJA, and ABA. Interestingly, overexpression of one of the TaSAUR family members, a nitrogen starvation responsive gene, TaSAUR66-5B, can promote the growth of Arabidopsis and wheat roots. In addition, overexpression of TaSAUR66-5B in Arabidopsis up-regulates the expression levels of auxin biosynthesis related genes, suggesting that overexpression TaSAUR66-5B may promote root growth by increasing the biosynthesis of auxin. Furthermore, overexpression of TaSAUR66-5B in wheat can increase the biomass and grain yields of transgenic plants, as well as the nitrogen concentration and accumulation of both shoots and grains, especially under low nitrogen conditions. This study provides important genomic information of the TaSAUR gene family and lays a foundation for elucidating the functions of TaSAURs in improving nitrogen utilization efficiency in wheat.     

一种提高稠油采收率的技术——混相水驱

铜油混相水驱是稠油吞吐热采降压开采后提高采收丰的一种技术。它是利用氮气、泡沫及活性剂各自不同的特性，来提高驱油效率和扩大波及体积，达到提高最终采收率的目的。经室内模拟认为：该技术比常规水驱驱油效率提高30%，采收率提高7%；配套工艺技术比蒸汽驱简单且投资少。     

滹沱河平原地下水矿化度和硬度变化分析

地下水为石家庄市的主要供水水源。在开采时间增长和开采量增加的作用下,地下水位下降且形成常年性地下水降落漏斗。地下水位下降对地下水质量的影响程度,一直为人们所关注。通过分析20世纪90年代以来滹沱河平原典型农业开采区的地下水水质资料,得出矿化度和总硬度与地下水位埋深密切相关的结论。     

基于数据预测的手机总全向灵敏度(TIS)的快速测试

手机总全向灵敏度（TIS）是OTA测试的重要指标之一。而基于CTIA的步进测试法,测试非常耗时。本文在深入研究基站发射功率和误码率关系的基础上,得出具有一定通用性的拟合函数,进而提出了一种基于数据预测的TIS测试方法。通过编写相应自动测试软件,实现快速测试。该法将大大提高测试效率,有很高的应用和推广价值。