一阶中立型时滞微分方程的振动性：祝贺肖伊莘教授八十寿辰

本文给出一类中立型微分方程振动的新的充分条件。     

Type III hyperlipoproteinemia associated with apolipoprotein E deficiency

Subjects with type III hyperlipoproteinemia develop premature atherosclerosis and have hyperlipidemia due to an increase in cholesterol-rich very low density lipoproteins (VLDL) of abnormal electrophoretic mobility. Apolipoprotein E is a major protein constituent of VLDL and appears to be important for the hepatic uptake of triglyceride-rich lipoproteins. A new kindred of patients with type III hyperlipoproteinemia is described in which no plasma apolipoprotein E could be detected, consistent with the concept that type III hyperlipoproteinemia may be due to an absence or striking deficiency of apolipoprotein E.     

Ulysses Radio Occultation Observations of the lo Plasma Torus During the Jupiter Encounter

Radio signals from Ulysses were used to probe the lo plasma torus (IPT) shortly after the spacecraft's closest approach to Jupiter. The frequencies of the two downlinks at S-band (2.3 gigahertz) and X-band (8.4 gigahertz) were recorded, differenced, and integrated in order to derive the columnar electron density of the IPT. The measurements agree qualitatively with contemporary models of the IPT based on Voyager data, but significant differences are apparent as well. The overall level of the IPT electron density is approximately the same as the prediction, implying that the amount of gas (or plasma) injected from lo is similar to that observed during the Voyager era. On the other hand, the IPT seems to be less extended out of the centrifugal equator, implying a smaller plasma temperature than predicted.     

射频等离子体对小麦种子萌发的影响

为了系统、深入的了解等离子体对作物影响的作用机理,采用射频等离子体处理小麦种子,测定了不同强度等离子体处理后的种子活力、萌发过程中淀粉酶活性、呼吸速率以及幼苗的根系活力的变化。结果表明,较低强度等离子体处理(80～200W)能提高小麦萌发过程中淀粉酶活性和呼吸强度,促进碳水化合物的转化和运输,使小麦种子的发芽率、发芽势和发芽指数分别提高30.0%、107.7%和53.5%。80～200W等离子体也能够提高小麦幼苗根系活力、促进根系发育,其中以160W等离子体作用效果最强,使根系活力提高39.65%、侧根数增加19.81%、根长增加7.85%。等离子体强度过高(240W)则表现出一定的抑制效应。     

基于1H NMR技术的奶牛I型和II型酮病血浆代谢谱分析

【目的】运用代谢组学中¹H NMR技术方法筛选出Ⅰ型酮病、Ⅱ型酮病与健康对照组之间血浆差异性代谢物。【方法】选取产后7—28 d,平均胎次为2—3胎的实验奶牛50头。根据血糖（Glc）、β-羟丁酸（BHBA）和游离脂肪酸（NEFA）的含量与临床发病特点分为Ⅰ型酮病、Ⅱ型酮病与健康对照组,其中Ⅰ型酮病20头,Ⅱ型酮病为20头,健康对照组为10头。当患病牛血中BHBA＞1.20 mmol·L^-1,Glc＜2.50 mmol·L^-1,NEFA＞0.50 mmol·L^-1时,被认为患I型酮病;当患病牛血浆中BHBA＞1.20 mmol·L^-1,Glc＞2.80 mmol·L^-1, NEFA＞0.50 mmol·L^-1时,被认为患II型酮病;当奶牛血中BHBA＜1.00 mmol·L^-1,Glc＞3.75 mmol·L^-1,NEFA＜0.40 mmol·L^-1时,被认为健康对照组。运用代谢组学中¹H NMR技术对实验奶牛的血浆代谢物分析,获得相应的代谢图谱,并结合多元统计分析中的主成分分析（PCA）、正交偏最小二乘判别分析（OPLS-DA）的模式判别,从而寻找潜在的生物标记物。【结果】通过¹H NMR分析,Ⅰ型酮病、Ⅱ型酮病与健康对照的代谢图谱差异明显,3组代谢产物各自聚集,分散区域显著。Ⅱ型酮病与健康对照比较,获得7种血浆差异代谢物,主要为丙氨酸、赖氨酸、β-羟丁酸、丙酮、乳酸等,其中血浆中β-羟丁酸、丙酮、乳酸浓度升高;丙氨酸、赖氨酸、酪氨酸、肌酸浓度呈现下降。Ⅰ型酮病与健康对照组比较,获得19种血浆差异代谢物,主要为酪氨酸、苯丙氨酸、肌酸、β-羟丁酸、丙酮等,其中β-羟丁酸、丙酮浓度升高;酪氨酸、苯丙氨酸、赖氨酸、组氨酸、丙氨酸、肌酸、肌醇、β-葡萄糖、谷氨酰胺、谷氨酸、柠檬酸、α-葡萄糖、甲酸、甘氨酸、O-乙酰葡萄糖胺、磷酸胆碱浓度呈现下降。Ⅰ型酮病与Ⅱ型酮病比较,获得24种血浆差异代谢物,主要为柠檬酸、组氨酸、β-葡萄糖、异亮氨酸、极低密度脂蛋白/低密度脂蛋白等,其中β-羟丁酸、低密度脂蛋白和极低密度脂蛋白、异亮氨酸、缬氨酸、丙酮、亮氨酸、乙酸浓度升高;柠檬酸、酪氨酸、组氨酸、肌醇、谷氨酰胺、β-葡萄糖、苯丙氨酸、谷氨酸、α-葡萄糖、赖氨酸、甲酸、甘氨酸、磷酸胆碱、丙氨酸、O-乙酰葡萄糖胺浓度呈现下降。【结论】¹H NMR技术与多元统计分析的有效结合能够有效的筛选出Ⅰ型酮病、Ⅱ型酮病与健康对照组之间血浆差异性代谢物,为进一步探究奶牛Ⅰ型酮病、Ⅱ型酮病的发病机理和诊断与防治提供了新的方向。     

四川桉树菌根类型及林分密度对菌根真菌的影响

四川人工桉树林中的巨桉、尾叶桉、兰桉、大叶桉有外生菌根、内生菌根和混合菌根 3种菌根类型 ,而窿缘桉缺少混合菌根类型。自然状态下 ,5种桉树菌根化率有明显差异 ,其中以巨桉、兰桉最高 ,分别为 6 8 3 %、6 4 6 % ,而窿缘桉菌根化率最低 (2 9 6 % )。同一桉树树种 ,外生菌根化率最高 ,内生菌根化率次之 ,混合菌根化率最低。林分郁闭度对菌根真菌的分布有很大影响 ,随着森林郁闭度增加 ,桉树林分外生、内生菌根真菌的类群趋于复杂     

一阶变系数中立型方程的振动性

In this paper we investigate the oscillation of a kind of first order neutral delay differential equations. Some sufficient conditions for the oscillation of all solutions and the existence of non-oscillatory solutions are obtained. Our results solve seve     

带强迫项的脉冲泛函微分方程的振动性

研究了一阶带强迫项脉冲泛函微分方程的振动性,得到方程的解具有振动性的充分条件,并找到在适当的脉冲控制下,方程的所有解都是振动的．     

直立型川麦冬生物学性状与块根产量相关性研究

［目的］研究直立型川麦冬优良新品系的生物学性状与块根产量相关性变化规律,为麦冬规范化生产提供科学依据。［方法］随机选取一般的直立型川麦冬植株序列15窝,测定植株高度、植株冠幅、总叶片数、分蘖数、块根数等生物学性状Xi和鲜块根总产量Y,用SPSS软件进行相关回归分析。［结果］川麦冬新品系的植株生物学性状对块根产量均有极显著的影响（P〈0.001）;其变化规律为：Y=-2.662 1＋0.538 1X1＋0.205 3X2＋0.005 1X4＋0.783 1X5＋0.292 9X6,影响程度分别为块根数〉分蘖数〉株高〉冠幅〉叶片数。［结论］促进麦冬块根数量增多膨大和增加植株分蘖、培育合理的植株构型是麦冬GAP可持续高产的有效措施。     

Radio astronomy with very large arrray

The construction of the Very Large Array of radio telescopes has been completed, and this new research instrument is now being used to make radio images of astronomical objects with a resolution comparable to or better than that of ground-based optical telescopes. The role of the Very Large Array in current and future research is discussed both in principle and in terms of a sample of observing projects.     

高阶非线性脉冲微分方程解的振动性

对高阶非线性脉冲微分方程解的振动性态进行了研究,得到了解振动的充分条件,对解性态的关键性影响因素进行了较深入的探讨.     

Very-Long-Baseline Radio Interferometry: The Mark III System for Geodesy, Astrometry, and Aperture Synthesis

The Mark III very-long-baseline interferometry (VLBI) system allows recording and later processing of up to 112 megabits per second from each radio telescope of an interferometer array. For astrometric and geodetic measurements, signals from two radio-frequency bands (2.2 to 2.3 and 8.2 to 8.6 gigahertz) are sampled and recorded simultaneously at all antenna sites. From these dual-band recordings the relative group delays of signals arriving at each pair of sites can be corrected for the contributions due to the ionosphere. For many radio sources for which the signals are sufficiently intense, these group delays can be determined with uncertainties under 50 picoseconds. Relative positions of widely separated antennas and celestial coordinates of radio sources have been determined from such measurements with 1 standard deviation uncertainties of about 5 centimeters and 3 milliseconds of arc, respectively. Sample results are given for the lengths of baselines between three antennas in the United States and three in Europe as well as for the arc lengths between the positions of six extragalactic radio sources. There is no significant evidence of change in any of these quantities. For mapping the brightness distribution of such compact radio sources, signals of a given polarization, or of pairs of orthogonal polarizations, can be recorded in up to 28 contiguous bands each nearly 2 megahertz wide. The ability to record large bandwidths and to link together many large radio telescopes allows detection and study of compact sources with flux densities under 1 millijansky.     

带脉冲的高阶线性时标微分方程的振动性（英文）

研究了带强迫项的一阶时标脉冲微分方程的振动性,得到几个时标方程的解具有振动性的判定条件,并举例说明了脉冲对时标系统解振动性的重要性.     

带脉冲的多时滞高阶线性泛函微分方程的振动性和渐近性(英文)

研究了一类带脉冲的高阶线性泛函微分方程,建立了无脉冲的微分方程的振动性和渐近性的比较原理,在此比较原理下得到了带脉冲的高阶线性泛函微分方程一些有用结论,通过寻找适当的脉冲函数可保证方程解的振动性和渐近性.最后通过实例验证了相关结论.     

带扩散系数的拟线性时滞脉冲现象的振动性

研究了一类带扩散系数的拟线性脉冲时滞抛物型方程组的振动性,利用振动的定义、Green公式和Newmann边值条件将这类脉冲时滞抛物方程组的振动问题转化为脉冲时滞微分不等式正解的不存在性问题,并利用最终正解的定义和脉冲时滞微分不等式,获得了该类方程组所有解(强)振动的充分条件.     

一类具有时滞和HollingⅢ类功能性反应的捕食系统的稳定性与Hopf分支

研究一类具有时滞和Hollingm类功能性反应的捕食系统,通过分析系统的特征方程,研究了正平衡点的局部稳定性,得到了系统出现Hopf分支的条件,利用中心流形定理和规范型理论,得到了确定Hopf分支方向和分支周期解稳定性的计算公式．