Countercurrent chromatography meets MS

Interfacing countercurrent chromatography with thermospray mass spectrometry provides a new analytical tool for detecting nonvolatile, hydrophilic or thermally unstable bioactive natural products.     

固体中氢,氘负离子的形成和电荷交换截面的测量

用电荷交换的观点,分析在束箔离子相互作用中的负离子形成过程.导出了负离子产额与电荷交换截面的关系为:φ~-=σ_(?)~2/(3σ_i~2).证明φ~-与入射核子速度有关,与停留时间无关.报告了在不同入射速度下,H~ ,D~ ,H_2~ ,D_2~ 和H_e~ 等种离子在碳膜中产生的H~-,D~-或H_e~-的测量结果.由此得到电子损失截面σ_l和电子浮获截面σ_c的观测值.     

球形闭孔膨胀珍珠岩的制造方法(Ⅱ)——球形闭孔膨胀珍珠岩的膨胀工艺研究

分析了球形闭孔膨胀珍珠岩的形成机理,介绍了球形闭孔膨胀珍珠岩的膨胀工艺及工艺流程并给出了实施例.     

去除硅石中气液包裹体的研究

利用差异腐蚀方法对各种石英矿物进行处理 ,结果表明 ,去除气液包裹体的效果明显 ,同时还发现 ,通过测定石英颗粒在浸油中的光透过率 ,能够检验石英矿物气液包裹体被去除的程度。这对于深入研究硅石代替水晶技术有重要意义     

A sphingosine-1-phosphate receptor regulates cell migration during vertebrate heart development

Coordinated cell migration is essential in many fundamental biological processes including embryonic development, organogenesis, wound healing and the immune response. During organogenesis, groups of cells are directed to specific locations within the embryo. Here we show that the zebrafish miles apart (mil) mutation specifically affects the migration of the heart precursors to the midline. We found that mutant cells transplanted into a wild-type embryo migrate normally and that wild-type cells in a mutant embryo fail to migrate, suggesting that mil may be involved in generating an environment permissive for migration. We isolated mil by positional cloning and show that it encodes a member of the lysosphingolipid G-protein-coupled receptor family. We also show that sphingosine-1-phosphate is a ligand for Mil, and that it activates several downstream signalling events that are not activated by the mutant alleles. These data reveal a new role for lysosphingolipids in regulating cell migration during vertebrate development and provide the first molecular clues into the fusion of the bilateral heart primordia during organogenesis of the heart.     

透明介质中单缝Fraunhofer′s衍射条纹的变化

研究Ｆｒａｕｎｈｏｆｅｒ′ｓ衍射装置由空气移至水或其它透明介质中衍射条纹间距的变化．在考虑到介质中光波波长会发生变化的同时,兼顾介质中透镜焦距的变化,从而进一步计算衍射条纹的间距,得出更符合事实的结论．     

试论新时期以来中国文艺学的大发展

新时期以来，中国文艺学获得了长足的多元的发展，这种大发展主要表现在文学观念冲破旧有束缚、张扬人文精神，在自律与他律的辩证统一中探索和把握文学的审美意识形态本质，并在此基础上促使文学理论走向多元和成熟；文学研究方法也在借鉴中外文论和其它学科研究方法的基础上取得突破和创新，有力推动了文艺学研究方法的多元化，反过来又促进了新时期文学观念的拓展和更新。     

TE10波在矩形波导管中传播的计算机模拟

编程模拟TE10波在矩形波导管中传播及驻波形成的动态图象.通过计算机图像模拟,可以更快、更深刻地掌握微波传输的原理.