ICP-MS法测定聚酯纤维中TiO2含量

采用湿法和微波法对聚酯纤维样品进行消解,利用电感耦合等离子体质谱联用仪(ICP-MS)对样品中TiO2含量进行了测定,得到湿法消解样品测定值2 857.46μg/g(相对标准偏差为1.08%),微波消解样品测定值2599.21μg/g(相对标准偏差为2.76%).分别测定了两种消解方法的检出限,湿法消解检出限为4.0 ...     

Resveratrol Promotes Angiogenesis in a FoxO1-Dependent Manner in Hind Limb Ischemia in Mice

Critical limb ischemia (CLI) is a severe form of peripheral artery diseases (PAD) and seriously endangers the health of people. Therapeutic angiogenesis represents an important treatment strategy for CLI; various methods have been applied to enhance collateral circulation. However, the current development drug therapy to promote angiogenesis is limited. Resveratrol (RSV), a polyphenol compound extracted from plants, has various properties such as anti-oxidative, anti-inflammatory and anti-cancer effects. Whether RSV exerts protective effects on CLI remains elusive. In the current study, we demonstrated that oral intake of RSV significantly improved hind limb ischemia in mice, and increased the expression of phosphorylated Forkhead box class-O1 (FoxO1). RSV treatment in human umbilical vein endothelial cells (HUVECs) could increase the phosphorylation of FoxO1 and its cytoplasmic re-localization to promote angiogenesis. Then we manipulated FoxO1 in HUVECs to further verify that the effect of RSV on angiogenesis is in a FoxO1-dependent manner. Furthermore, we performed metabolomics to screen the metabolic pathways altered upon RSV intervention. We found that the pathways of pyrimidine metabolism, purine metabolism, as well as alanine, aspartate and glutamate metabolism, were highly correlated with the beneficial effects of RSV on the ischemic muscle. This study provides a novel direction for the medical therapy to CLI.     

CVD样品台旋转对沉积金刚石涂层的影响

以CH3COCH3和H2为反应气源,利用热丝化学气相沉积(HFCVD)方法,通过改变样品台的旋转频率在YG6硬质合金(WC-6wt; Co)基体上沉积金刚石涂层.利用X射线衍射分析YG6硬质合金表面沉积金刚石涂层物相,通过扫描电子显微镜和压痕试验机分析金刚石涂层的表面形貌、沉积厚度和膜基结合性能,考察了样品台旋转频率对沉积金刚石涂层结构与性能的影响,以确定最佳的样品台旋转频率.结果 表明,在固定沉积工艺参数条件下,当样品台的旋转频率为2次/h时,在YG6硬质合金基体上沉积的金刚石涂层具有较优的晶粒和更均匀致密的聚晶结构以及更高的膜-基结合力.     

CVD金刚石薄膜表面的缺陷研究

用SEM方法观察分析了CVD金刚石薄膜表面的缺陷形貌和结构,直观的两种缺陷为孪晶和孔洞.孪晶反映了晶粒的不完整性,它的产生取决于气相中活性分子的浓度与生长表面活性位数目的比值,孪晶比率随碳源浓度升高和衬底温度的降低而增大;孔洞反映了膜的不致密性,其产生与膜生长速率和衬底表面初始成核密度切相关,孔洞密度随碳源浓度升高和衬底温度的升高而增大.     

The blood flow and the motion of vessel wall

The correlation problem between the blood flow and the motion of vessel wall in the mammalian circulatory system is discussed in this paper. Supposing the blood flow is under the stable oscillatory condition, a set of formulas for velocity distribution, pressure distribution, displacement of vessel wall and constraining stress are obtained. Kuchar’s formulas are extended from steady flow to unsteady oscillatory flow by means of the formulas obtained in this paper. The problem of elasticity effect of vessel wall is also discussed.     

The Total Synthesis of (±)-13-Hydroxyneocembrene

(13S)-hydroxyneocembrene(18), a cembranoid which was isolated in 1988 from soft coral Sarcophyton trocheliophorum¹, has been shown to be an effective inductor of the release of labeled glucose from the lecithincholesterol liposomes and have cytostatic activities². The geometrical structure and absolute configuration of 18 have been defined to be 1S, 2E, 7E, 11E, 13S. Herein, we report the total synthesis of (±)-13hydroxyneocembrene(18).     

An application of nonsymmetric Lax-Milgram lemma to nonassociated plasticity

Based on a general assumption for plastic potential and yield surface, some properties of the nonassociated plasticity are studied, and the existence and uniqueness of the distribution of incremental stress and displacement for work-hardening materials are proved by using nonsymmetric Lax-Milgram lemma, when the work-hardening parameter A>F/Q/–F/, Q/.     

自成像魏格纳函数分析

在空域-频域空间,基于魏格纳变换和魏格纳分布函数,分析讨论了一维物体的自成像及其形成过程.从成像过程中各衍射频谱分量的光程差,给出了Talbot效应和Montgomery效应的统一解释.对于周期物的Talbot效应,得到了用杨氏双缝干涉解释自成像现象的理论依据.周期物的自成像是物平面上间距为两倍周期、光程差为波长的整数平方倍的各衍射频谱分量同相相干迭加的结果.Montgomery效应是物平面上间距为抛物线关系、光程差为波长整数倍的各衍射频谱分量同相相干迭加的结果.     

大气压直流氩等离子体射流工作特性研究

介绍了一种新型大气压直流双阳极等离子喷枪,并对其电特性参数和发射光谱进行了测量.通过对氩等离子体射流的电信号进行时域和频域分析,研究了载气流量和弧电流的变化对射流脉动的影响,结果表明氩等离子体电弧的伏安特性呈上升趋势,射流脉动属于接管模式,电源特性中的交流分量引起的电压波动是影响氩等离子体射流脉动的主要因素. 通过光谱法测量了氩等离子体射流在弧室内和弧室出口的发射光谱,利用玻尔兹曼曲线斜率法计算了射流的激发温度,根据Ar I谱线的斯塔克展宽得到了射流的电子密度,并对等离子体射流满足局域热力学平衡(LTE) 关键词： 等离子喷枪 射流脉动 激发温度 局域热力学平衡