Synthesis of a novel series of 10-oxa-3-aza-tricyclo[5.2.1.0]dec-8-en-4-ones through an intramolecular Diels-Alder reaction

The synthesis of a novel series of 10-oxa-3-aza-tricyclo[5.2.1.0^1,5]dec-8-en-4-ones through the use of the intramolecular Diels-Alder reaction is presented. The use of this reaction allows for the synthesis of functionalized polycyclic systems in a stereocontrolled manner.     

在弱碱性及中性介质中AISI304不锈钢载波钝化膜光电化学研究

采用光电化学方法－恒电位光电流测量技术研究了ＡＩＳＩ３０４不锈钢在０．１ｍｏｌ／ＬＮａ２Ｂ４Ｏ７及０．５ｍｏｌ／ＬＮａ２ＳＯ４介质中载波钝化膜，光电流测量结果表明，光电流大小与电极电势、成膜条件及测量介质有关，载波钝化膜基本上是高度无序的非晶态膜。     

Effects of mechanical boundary conditions on thermal shock resistance of ultra-high temperature ceramics

The effects of mechanical boundary conditions, often encountered in thermalstructural engineering, on the thermal shock resistance (TSR) of ultra-high temperature ceramics (UHTCs) are studied by investigating the TSR of a UHTC plate with various types of constraints under the first, second, and third type of thermal boundary conditions. The TSR of UHTCs is strongly dependent on the heat transfer modes and severity of the thermal environments. Constraining the displacement of the lower surface in the thickness direction can significantly decrease the TSR of the UHTC plate, which is subject to the thermal shock at the upper surface. In contrast, the TSR of the UHTC plate with simply supported edges or clamped edges around the lower surface is much better.     

柱前衍生高效液相色谱法测定减肥药中的芬氟拉明

建立了柱前衍生反相高效液相色谱—紫外检测方法用于测定减肥药中的芬氟拉明。样品用三氯甲烷萃取,异丙醇转溶,再在四氢呋喃中和60℃下,用苯异氰酸酯衍生35min,然后用甲醇／水(72／28,V／V)为流动相和Kromasil C18分离柱,在240nm检测衍生物。方法的线性范围在2．52—126mg／L(r=0．9994),检出限和定量限分别为0．36ng(S／N=3)和1．2ng(S／N=10),平均回收率为98．4％,相对标准偏差(RSD)小于3．00％。     

高效液相色谱法测定乌梅有机酸

采用Kromnsil C18为分析柱,0．0lmol／L磷酸盐缓冲溶液(pH2．7)为流动相,紫外215nm检测,建立了乌梅中草酸、酒石酸、苹果酸、乳酸、乙酸、柠檬酸、琥珀酸等多种有机酸的高效液相色谱方法。方法的回收率为98％～105％;RSD为2．26％～7．82％;检出限为10～75ng(S／N=3)。测定了4种不同产地和种类的乌梅中的苹果酸、乳酸、乙酸、柠檬酸、琥珀酸的含量。     

Microfluidic techniques for tumor cell detection

Cancer metastasis is the main cause of cancer‐related death. Early detection of tumor cell in peripheral blood is of great significant to early diagnosis and effective treatment of cancer. Over the past two decades, microfluidic technologies have been demonstrated to have great potential for isolating and detecting tumor cell from blood. The present paper reviews microfluidic techniques for tumor cell detection based on various physical principles. The specific methods are categorized into active and passive methods depending on whether extra force field is applied. Working principles of the two methods are explained in detail, including microfluidics combined with optical tweezer, electric field, magnetic field, acoustophoresis, and without extra fields for tumor cell detection. Typical experiments and the results are reviewed. Based on these, research characteristics of the two methods are analyzed.     

Experimental investigation of penetration performance of shaped charge into concrete targets

In order to develop a tandem warhead that can effectively destroy concrete targets, this paper explores the penetration performance of shaped charges with different cone angles and liner materials into concrete targets by means of experiments. The penetration process and the destruction mechanism of concrete targets by shaped charges and kinetic energy projectiles are analyzed and compared. Experimental results suggest that both kinetic energetic projectile and shaped charge are capable of destroying concrete targets, but the magnitudes of damage are different. Compared with a kinetic energy projectile, a shaped charge has more significant effect of penetration into the target, and causes very large spalling area. Hence, a shaped charge is quite suitable for first-stage charge of tandem warhead. It is also found that, with the increase of shaped charge liner cone angle, the depth of penetration decreases gradually while the hole diameter becomes larger. Penetration depth with copper liner is larger than of aluminum liner but hole diameter is relatively smaller, and the shaped charge with steel liner is between the above two cases. The shaped charge with a cone angle of 100° can form a jet projectile charge （JPC）. With JPC, a hole with optimum depth and diameter on concrete targets can be formed, which guarantees that the second-stage warhead smoothly penetrates into the hole and explodes at the optimum depth to achieve the desired level of destruction in concrete targets.     

XPS and XRD study of FeCl3-graphite intercalation compounds prepared by arc discharge in aqueous solution

A novel one-step synthesis method of FeCl₃–graphite intercalation compounds (FeCl₃–GICs) by an arc discharge in aqueous solution was reported for the first time. It presented a simply and controllable way to synthesize FeCl₃–GICs. The structure of the stage 7 GICs was examined and characterized by X-ray diffraction. X-ray photoelectron spectroscopic study of stage 7 of FeCl₃–GICs was also carried out. The change in the binding energy suggests the nature of charge transfer and lowering of Fermi level as has been reported previously for other acceptor intercalation compounds.