浅谈《塑料模具设计》课程的教学改革

根据塑料模具行业发展的需要,教学过程中应精选内容,采用合理的教学方法,利用现代教育技术优化课堂教学,注重学生实践创新能力的培养.     

硫酸四氨合铜的制备及组成测定的实验研究

探讨了“硫酸四氨合铜的制备及组成测定”实验的设置及在高等医学院校基础化学实验课程中的开设情况，结果表明：增设该实验后，以加强学生综合实验能力的训练很有益处。     

基础化学实验中常规实验与微型实验的比较

化学实验微型化是目前教学实验的一个重要发展趋势,该文就硫酸亚铁铵制备的常规实验与微型实验进行了比较,微型化学实验不但可以达到常规实验相同的实验目的和效果,而且大大减少试剂用量,并可在一定程度上解决实验过程产生的化学废弃物,改善实验室的空气品质。     

A cause of water-sensitivity in modern oil paint films: The formation of magnesium sulphate

Unvarnished twentieth-century oil paintings are often sensitive to aqueous swabbing, a method routinely employed by conservators for surface cleaning. This study proposes a connection between sensitivity and the presence of magnesium sulphate heptahydrate which has been identified on the surface of some of water-sensitive paintings. The probable source of magnesium is magnesium carbonate, an additive in some twentieth-century oil paints, which has reacted with atmospheric sulphur dioxide (SO₂). Films made using modern manufactured paints and formulations made in the laboratory were exposed to gaseous SO₂ and raised relative humidity and examined using scanning electron microscopy with energy dispersive X-ray spectroscopy and X-ray diffraction to characterize the crystalline entities. Films containing magnesium carbonate formed magnesium sulphite and sulphate hydrates. Films containing zinc oxide were also investigated. These formed zinc and sulphur containing salts. Sensitivity to swabbing with water before and after exposure was evaluated. Films that developed salts, demonstrated increased sensitivity to aqueous swabbing after exposure to SO₂. Findings suggest that increased water sensitivity may be due to a combination of the formation of hygroscopic degradation products and to weakening of the paint film due to salt-induced disruption of the surface.     

LTE和LTE-Advanced关键技术探究

作为新一代宽带业务的国际标准(4G时代),LTE网络采用了许多新技术。它采用扁平化网络构架的方式进行设计,包括一些聚合多载波、异构网络、中继、多点发送、MIMO和先进的抗干扰管理等技术。这些技术极大地提高了小区边缘用户的一些性能,使小区的信息传输速率和系统容量得以增加。     

硫酸钡混悬液产品配方优化

利用正交试验探讨了六偏磷酸钠、枸橼酸钠、羧甲基纤维素钠（CMC）等助剂对医用硫酸钡混悬液产品稳定性的影响,得到的最优化质量浓度组合（g／ml）为六偏磷酸钠：CMC：枸橼酸钠-3：2：5。其中CMC因子对稳定性结果影响最大。该研究能为医用硫酸钡混悬液生产工艺的控制和改进提供有益的参考。     

电位法测定水中硫酸盐的研究

提出了用离子选择电极电位法测定硫酸盐的新方法.在最佳条件下,电极电位与硫酸盐浓度在1×10-5～1×10-2mol/L之间有良好线性关系,检测下限为6.3×10-6/mol/L.该方法简便准确,已用于水中硫酸盐测定,结果满意.     

丙烯酸／聚乙二醇单甲醚丙烯酸酯二元共聚物阻垢性能研究

以丙烯酸、聚乙二醇单甲醚（分子量为400,1000）丙烯酸酯为原料,合成了两种含膦酰基醚基羧基的共聚物阻垢荆T-400和T-1000,以静态阻垢方法分别从阻垢剂用量、钙离子浓度、阻垢时间、阻垢温度及溶液pH值考察了侧链聚醚聚合度不同的两种阻垢剂对阻碳酸钙垢、硫酸钙垢性能的影响差异．结果表明,T-400、T-1000两种共聚物阻垢剂具有优良的阻碳酸钙垢性能和优异的阻硫酸钙垢性能;共聚物用量为12mg／L时,侧链聚醚聚合度小的共聚物T-400阻碳酸钙垢性能优于T-1000;共聚物用量为4mg／L时,侧链聚醚聚合度大的共聚物T-1000阻硫酸钙垢性能优于T-400．     

The role of DHEA-S in the mood adjustment against negative competition outcome in golfers

Abstract

Several lines of evidence suggest that dehydroepiandrosterone sulphate (DHEA-S) is invariably consumed following different types of acute stress, implicating its role in stress coping and recovery. The role of DHEA-S in the mood adjustment against negative outcome for athletic competition has not previously been investigated. In the current study, 14 elite golfers participating in a major national golf tournament were subsequently divided into two groups according to their competition outcomes: made the cut (n = 8) and failed to make the cut (n = 8). The Profile of Mood States (POMS) inventory and plasma concentrations of DHEA-S and cortisol were measured 1 day before the beginning of competition (baseline) and 1, 3, and 5 days after the players' final competition, in the morning (08.00–08.30 h) under fasted conditions. Results showed that the total mood disturbance scores and DHEA-S were not changed for the group that made the cut throughout the entire observation period. DHEA-S concentration for the group that failed to make the cut fell significantly below baseline values on day 1 and remained lower for 5 days. The Depression subscale of the POMS for the group that failed to make the cut was increased only on day 1 post-competition, reflecting a situational reaction to the event. Cortisol concentration for the group that made the cut fell significantly below baseline values on day 1 only after competition and no change was observed for the group that failed to make the cut. In conclusion, although the overall mood state post-competition was well-maintained for those golfers who had a negative competition outcome, plasma DHEA-S concentration was reduced for 5 days, suggesting that it has a role in the coping mechanism against psychological challenge.     

Kinetics of acoustic release of doxorubicin from stabilized and unstabilized micelles and the effect of temperature

Ultrasound is being investigated as a trigger mechanism to deliver high concentrations of chemotherapy drugs to cancerous tissues using polymeric micelles. In this paper, we examined the kinetics of acoustic release of doxorubicin using stabilized and non-stabilized micelles. Kinetic models were used to regress release and re-encapsulation time constants for three different compounds, namely non-stabilized Pluronic^® P105 micelles, P105 micelles stabilized using an interpenetrating network of N,N-diethylacrylamide and micelles formed by PEO-b-poly(NIPAAm-co-HEMA-lactate_n). Results showed that the kinetic release constant (k_r) depends on the micellar system under investigation. On the other hand, there is no statistically significant difference between re-encapsulation rate constants for stabilized and unstabilized micelles. We hypothesize that k_r depends on the degree of cross-linking or stabilization.