介质靶表面的充电效应对等离子体浸没离子注入过程中鞘层特性的影响

针对等离子体浸没离子注入技术在绝缘体表面制备硅薄膜工艺，采用一维脉冲鞘层模型描述介质靶表面的充电效应对鞘层厚度、注入剂量及靶表面电位等物理量的影响.数值模拟结果表明：随着等离子体密度的增高，表面的充电效应将导致鞘层厚度变薄、表面电位下降以及注入剂量增加，而介质的厚度对鞘层特性的影响则相对较小. 关键词： 等离子体浸没离子注入 脉冲鞘层 绝缘介质 充电效应     

Investigation on Ochratoxin A stability using different extraction techniques

The stability of Ochratoxin A during its extraction using different extraction techniques has been evaluated. Microwave-assisted extraction and pressurised liquid extraction, in addition to two other reference methods of extraction, i.e. ultrasound-assisted and magnetic stirring-assisted extraction, were evaluated. The effect of extraction temperature using the cited techniques was checked.The results show that Ochratoxin A can be extracted using microwave-assisted extraction at temperatures up to 150 °C without degradation. Pressurised liquid extraction can be used at temperatures up to 100 °C, for extraction times of less than 30 min. Further, both ultrasound-assisted extraction and magnetic stirring extraction can be applied at temperatures up to 65 °C.High-performance liquid chromatography combined with fluorescence detection using a Chromolith RP-18e column at a flow rate of 5 mL min⁻¹ was used to quantify the Ochratoxin A. The retention time for the Ochratoxin A was 1.3 min. The limits of detection (LOD) and of quantification (LOQ) were 0.03 and 0.10 μg L⁻¹, respectively.     

Curvature Conditions for Immersions of Submanifolds and Applications

Some curvature conditions about the geodesics emanating from a submanifold are obtained. These conditions are used to to study the topological and geometric properties of the ambient spaces which admit some minimal submanifolds.     

Photoelastic stress freezing analysis of total shoulder replacement systems

Photoelastic stress freezing analyses in the orthopaedic literature have, in the past, been limited to studies where bone-on-bone, bone-on-metal or ultra-high molecular weight polyethylene (UHMWPE)-on-metal constructs are modeled. In these cases photoelastic plastics are used to simulate either bone or UHMWPE as it interacts with a metal implant. In joints such as the shoulder, a UHMWPE component is often cemented directly into the scapula's glenoid concavity using polymethylmethacrylate (PMMA). While a photoelastic material can be used to simulate bone with proper load scaling, UHMWPE and PMMA have very different mechanical properties at elevated stress freezing temperatures as compared within vivo body temperature. In this study, materials were identified such that proper scaling of elastic properties at elevated temperatures was utilized to simulate the metal-UHMWPE-PMMA-bone construct. Stresses on orthogonal planes throughout the glenoid were compared for two different UHMWPE component anchoring geometries (keeled and pegged). High stresses were found at the neck of the glenoid and also at the component-bone interface beneath simulated PMMA inclusions.     

Total absolute curvature and tightness of noncompact manifolds

In the first part we prove an extension of the Chern-Lashof inequality for noncompact immersed manifolds with finitely many ends. For this we give a lower bound of the total absolute curvature in terms of topological invariants of the manifold. In the second part we discuss tightness properties for such immersions. Finally, we give an upper bound for the substantial codimension.

     

Differential geometry of tensor product immersions

In this article we obtain the best possible estimates of the type number of tensor product immersions and investigate tensor product immersions with lowest possible type. Several classification theorems in this respect are then proved.     

大鼠肾组织的超低温快速冷冻固定和冷冻置换研究

超低温快速冷冻固定以极高的冷冻速率（１００００Ｋ／ｓ）对生物组织进行物理固定，可使生物组织结构、组织内可溶性离子及游离性物质得到保存，使被固定后的生物组织保持最接近于原自然状态，这种样品制备方法大大优于化学制备法，因而在Ｘ－射线微分析及免疫细胞化学中得到广泛应用。生物样品超低温快速冷冻后，利用冷冻置换法，在低温下将生物组织内的结晶水缓慢置换出来，而后常规包埋切片，可获得理想的组织结构及组织内待分析成分。本文应用超低温快速冷冻固定技术及冷冻置换法对大鼠肾皮质部的快速冷冻固定及损伤进行探讨。     

Characterization of the Nanoscale Microstructure of an Immersion Silver on Sputtered Copper

1 INTRODUCTION Silver and its compounds have received much attention due to their current and potential applica- tions in many areas[1, 2]. As a metal with the highest electrical and thermal conductivities, silver was one of the most important noble metals used in electrical industries in the last century. Several decades ago, however, the development of silver application in electronic area seemed not so quick. The fear for some undesirable phenomena involving silver, like “electrochemi…     

3-D-electron microscopy configuration of TMOS wet silica gels prepared by the quick-freeze,deep-etching-rotary-replication technique

Silica gel provides a useful medium for crystal growth; solution growth is confined to pores left free by the polymer during its development. All growth steps depend on the gel structure, which is not completely known for crystal growth conditions. Therefore, a three-dimensional (3-D) visualization has been performed for two TMOS aqueous gels, which are rather fragile: the quick-freeze, deep-etching, rotary-replication method has been applied for sample preparation. An original surface labeling technique has been used for surface recognition. The results concern the distribution of macropores that are responsible for crystal nucleation; micropores whose total volume is larger have not been visualized due to the limits of the method. These results are discussed in comparison with previous data performed by light scattering.     

γ-聚谷氨酸在细胞冻存中的作用

无DMSO、无血清细胞冻存液在临床级细胞产品的冷冻保存中具有重要的应用价值。本文以K562细胞为模型,设置含10%(v/v)DMSO及胎牛血清的冻存液为阳性对照,含10%(v/v)甘油的RPMI 1640培养基冻存液为阴性对照组,含10%(v/v)甘油及0.01%(w/v)γ-PGA的RPMI 1640培养基冻存液为实验组,考察了在无DMSO、无血清细胞冻存体系中γ-聚谷氨酸对细胞的冷冻保护作用。将K562细胞以1×10^6cells/mL的密度分别悬浮在上述冻存液中,置于液氮冻存10周,检测复苏后K562的细胞复苏率、细胞形态以及复苏后细胞的扩增情况,以评判γ-聚谷氨酸在无DMSO无血清冻存液中对K562细胞的冷冻保护作用。结果显示,实验组的细胞复苏率为(83.00±3.00)%,明显高于阴性对照组的(70.33±5.51)%(p<0.05)和阳性对照组的(71.00±2.65)%(p<0.05);且实验组冻存后的细胞形态完整,冻存前后细胞的平均直径及圆度基本一致,细胞复苏后培养24h后的细胞活性为(88.83±14.29)%,明显高于阴性对照组的(67.51±5.20)%(p<0.05),与阳性对照组的(78.75±3.31)%没有显著性差异,同时复苏后细胞扩增的延滞期明显缩短。可见,在无DMSO、无血清的甘油冻存体系中添加γ-PGA可显著提高细胞的冻存效果,具有良好的实际应用价值。