铁苋菜黄酮类化合物的提取及清除羟自由基作用的研究

采用不同的提取剂对铁苋菜黄酮类化合物进行了提取,通过单因素实验及正交实验对铁苋菜黄酮类化合物提取的工艺条件进行了探讨,对铁苋菜提取物的抗氧化活性进行了初步研究。结果表明,乙醇、水、甲醇、丙酮4种提取剂,乙醇的提取效果最好,铁苋菜黄酮提取的最佳工艺条件是温度80℃、乙醇浓度55%、料液比1∶35g/mL、提取时间为3.0h,此条件下黄酮的提取率为90.82%。铁苋菜黄酮类化合物对羟自由基具有一定的清除作用。     

超临界二氧化碳提取沙芥总黄酮的工艺

采用超临界CO2萃取法提取沙芥中总黄酮,通过单因素试验和正交试验考查提取温度、提取压力、提取时间和夹带剂流速对沙芥黄酮提取结果的影响,确定沙芥总黄酮超临界CO2提取工艺的最佳条件.结果表明,最佳参数组合为:温度35℃,压力30MPa,提取时间2.5h,80％乙醇流速0.2mL/min,在此工艺条件下沙芥黄酮的提取率为9.20mg/g.     

微波提取结香花黄酮的工艺

以结香花为原料,采用微波辅助提取法,探讨微波功率、乙醇浓度、料液比和提取时间等因素对结香花黄酮提取效果的影响,在单因素实验的基础上,设计L9（3^4）正交试验优化结香花黄酮提取的最佳工艺条件。结果表明,结香花黄酮提取的最佳工艺条件为：微波功率500W,乙醇浓度60％,料液比1：15g／mL,提取时间12min,在此实验条件下,结香花黄酮的提取量为15．35mg／g。     

正交设计优选银杏黄酮苷的超声提取条件

使用正交设计优化超声提取银杏黄酮苷的工艺条件。得到的最佳提取条件为:对于1g原料,采用60%乙醇水作提取溶剂,盐酸调节其pH值为4.5,在温度50℃下超声提取40min,黄酮苷的平均提取率为81.38%。该工艺简单、无污染且重复性好,适合大量制备银杏黄酮苷。     

马蹄金中黄酮成分分析

为了进一步开发利用马蹄金的资源,用光谱法对马蹄金中黄酮类成分进行定性分析和定量测定,并利用正交设计优选马蹄金中总黄酮的提取条件。结果表明,马蹄金中含有黄酮类、黄酮醇类、异黄酮类等多种黄酮成分。总黄酮提取的最佳条件是:用70%乙醇在50℃下超声波提取1.5h、提取体积80mL、提取一次。马蹄金中总黄酮的含量为0.937%,平均回收率为100.3%,RSD=0.38%(n=6)。此结果为马蹄金药效功能的进一步研究和资源开发利用提供科学依据。     

峨崛岩白菜叶和根状茎总黄酮提取工艺研究

采用微波辅助提取法,以总黄酮含量为考察指标,通过单因素实验和正交试验优选出峨嵋岩白菜叶和根状茎总黄酮微波最佳提取工艺.实验结果表明,峨嵋岩白菜叶中总黄酮提取的最佳工艺条件为:乙醇浓度60%.料液比1:30.微波时间60s/次,微波功率480w,提取次数为3次,黄酮含量为15.181mg/g;根状茎中总黄酮最佳工艺条件为:乙醇浓度60%,料液比1:20,微波时间75s/次,微波功率480w,提取次数为2次,黄酮含量为2.066mg/g.峨嵋岩白菜叶中总黄酮含量较根状茎中丰富,微波辅助提取法适合峨嵋岩白菜有效成分的提取.     

白芷的提取工艺

探讨多因素实验条件对白芷的提取工艺参数的影响,以欧前胡素和异欧前胡素的含量为指标,以乙醇浓度、乙醇用量、提取时间、提取次数为因素进行单因素试验。结果表明,白芷的最佳提取工艺参数为:以8倍量80%乙醇提取3次,每次lh。     

南天竹叶总黄酮的提取工艺

利用L16(44)正交试验设计和Duncan法检验,确立了南天竹叶总黄酮的最佳提取条件及其提取率.结果表明,用1:40(g/mL)的60%乙醇水溶液,提取温度为50℃,提取时间为3h,提取效率较好.最佳工艺条件下黄酮提取率为4.6330%.     

超声波强化响应面法优化提取桔皮黄酮

从提取溶剂及提取条件等方面对柑桔皮总黄酮超声波辅助提取工艺进行优化研究.以黄酮得率为考察指标,用单因子试验对提取溶剂进行筛选,用析因试验对提取条件进行分析,通过最陡爬坡试验和中心组合设计试验,优化超声波辅助提取工艺.结果表明,乙醇和水组成的复合体系是理想的提取溶剂;液料比、提取时间、乙醇浓度、pH值都对柑桔皮总黄酮提取产生一定的影响,其中液料比和提取时间的影响最为显著.超声波辅助提取工艺优化条件为:液料比37mL/g,提取时间83min;在此条件下总黄酮的最大提取量为3.321%.经验证试验表明,该方法是一种实用的提取方法.     

超声-微波协同辅助溶剂法提取喜树果中黄酮化合物的研究

超声-微波协同辅助溶剂法和普通溶剂法提取喜树果黄酮,紫外-可见分光光度法确定其含量。喜树果中黄酮化合物的优化工艺为:提取时间4—8min、提取溶剂中乙醇体积分数70%、料液比1∶6,优化工艺条件下总黄酮的产率可达1.13%。与普通溶剂法相比,超声-微波协同辅助溶剂法提取时间大为缩短,工艺效率显著提高,是一种具有绝对优势的喜树果中黄酮化合物的提取方法。     

关于"太阳在银河系中所受引力与到银心距离r的关系"的讨论

讨论了银道面内的引力场强分布和太阳在银河系中所受引力与到银心距离r的关系，指出引力场强g并不是与r的平方成反比，这是由于银河系的大小和形状不能忽略造成的．强调了万有引力定律的适用条件．     

Set the controls for the heart of the Sun

In this paper we describe experiments conducted with high-power lasers that are attempting to replicate, for a very short time and in miniature, conditions found in the Sun. Experiments to date have reached conditions in the outer part of the Sun. To reach the Sun's centre requires compression of material to very much greater than solid density and heating to over ten million degrees. To achieve this, a new class of experiments and a new generation of high-power lasers are required.     

Dependence of the Intensity of the Spectral Lines and the Composition of the Sample and the Plasma Parameters of the Unipolar Arc

The investigation was made of the dependence of the intensity of Tl, Ga, Mo, Mg, Mn, Sn, Bi, Ni, Zn, Pt and Au spectral lines and the plasma parameters (temperature T, electron concentration n_e, degree of 6 ionnization α) from concentration of lithium additive.     

干涉仪系统传递函数测量及影响因素的分析

波前功率谱密度(PSD)被用于评价惯性约束聚变(ICF)激光驱动器光学元件中频段的波前误差。干涉仪对PSD较高空间频率分量的测量存在失真效应,可通过干涉仪系统传递函数(STF)的检测标定来获得真实的波前PSD分布。采用台阶板位相比较法测得大口径菲索相移干涉仪检测系统在透射和反射检测情形下的传递函数。对传递函数测试算法进行了比较分析,明确了干涉仪系统zoom倍率的改变等因素对传递函数测量的影响,为波前PSD的准确检测奠定了基础。     

From the Solution of the Tsarev System to the Solution of the Whitham Equations

We study the Cauchy problem for the Whitham modulation equations for increasing smooth initial data. The Whitham equations are a collection of one-dimensional quasi-linear hyperbolic systems. This collection of systems is enumerated by the genus g=0,1,2, ... of the corresponding hyperelliptic Riemann surface. Each of these systems can be integrated by the so-called hodograph transformation introduced by Tsarev. A key step in the integration process is the solution of the Tsarev linear overdetermined system. For each g>0, we construct the unique solution of the Tsarev system, which matches the genus g+1 and g–1 solutions on the transition boundaries.     

On the Problem of the Amenability of the Gauge Group

Let G be one of the local gauge groups C(X, U(n)),C (X, U(n)), C(X, SU(n)) or C (X, SU(n)) where X is a compact Riemannian manifold. We observe that G has a nontrivial group topology, coarser than its natural topology, w.r.t. which it is amenable, viz. the relative weak topology of C(X, M(n)). This topology seems more useful than other known amenable topologies for G. We construct a simple fermionic model containing an action of G, continuous w.r.t. this amenable topology.     

On the stability of the equilibria of the Rikitake system

In this note we present an analytical study of the stability of the equilibria of the Rikitake system. We prove that the two non-hyperbolic equilibria of the Rikitake system are unstable for all positive values of the parameters.     

Testing the mechanism for the LSP stability at the LHC

The lightest supersymmetric particle (LSP) is a natural candidate for the cold dark matter of the universe. In this Letter we discuss how to test the mechanism responsible for the LSP stability at the LHC. We note that if R-parity is conserved dynamically one should expect a Higgs boson which decays mainly into two right-handed neutrinos (a “leptonic” Higgs) or into two sfermions. The first case could exhibit spectacular lepton number violating signals with four secondary vertices due to the long-lived nature of right-handed neutrinos. These signals, together with the standard channels for the discovery of SUSY, could help to establish the underlying theory at the TeV scale.     

地球的扁率对卫星运动的影响

指导出地球引力场的势能,分析了卫星的椭圆轨道旋进的现象。