Quaternary phosphonium modified epoxidized natural rubber: effect of reaction time,reaction mechanism,thermal property and antimicrobial activity

Herein we endow epoxidized natural rubber with antimicrobial activity by chemical modification. The rubber is firstly ring-opened by bromoacetic acid and then modified by antimicrobial group quaternary phosphonium salt. Using the hydrogen nuclear magnetic resonance spectroscopy (¹H NMR) and the ICP atomic emission spectrometry (ICP-AES), the degree of epoxidation, the convert ratio of epoxy groups, and the phosphorus content of the products are measured, and then the effects of reaction time on the structure of products are investigated. The possible reaction mechanism and side reactions in ring-opening procedure are discussed through the comparison of data with different reaction time, and the ring-expansion reaction is supposed to be dominated in the side reactions. The thermal properties of modified rubbers and the structural factors behind are also investigated using differential scanning calorimeter and thermogravimetric analyzer. Antimicrobial activities of modified rubbers with different ring-opening reaction time toward Escherichia coli are studied, and the activity may increase with the content of quaternary phosphonium salt groups. This research may have the benefit for optimizing the structure of chemically modified antimicrobial rubbers.     

P(BS-co-BA)和P(BS-co-BSE)的合成与扩链研究

用癸二酸、己二酸部分取代丁二酸,通过熔融溶液相结合的聚合方法,得到两者一系列的共聚物。通过数均分子量和熔点两个指标,得出最佳取代比例为20%癸二酸取代丁二酸的共聚物(PBSE-20)和20%己二酸取代丁二酸的共聚物(PBSA-20)。用异佛尔酮二异氰酸酯(IPDI)对这两种共聚物进行扩链改性,结果表明:扩链后,其数均分子量大小顺序为PBS>PBSA-20>PBSE-20,分子量分布均小于扩链前;且断裂伸长率均大于扩链前,各聚合物的热分解温度均大于300℃。阐述了脂肪族聚酯分子量、熔点及分子结构对称性与降解性能之间的关系。     

煤焦油对煤微波辅助萃取率的影响研究

以煤焦油蒸馏所得馏分为萃取溶剂,对煤在微波辅助条件下的萃取过程进行研究,主要考察了不同溶煤比和微波辐射时间等因素对萃取率的影响.结果表明,当溶煤比为3∶1且微波辐射为25 min时的萃取率最高,可以达到25.51%,有望为低温煤焦油的合理利用提出一种新途径.萃取残煤的FT-IR和SEM分析检测表明,萃取后残煤样的H/C降低,但煤的大分子结构没有受到破坏.     

PBO与T700纤维及其复合材料的性能研究

本文对具有21世纪超级纤维之称的PBO纤维与目前在先进复合材料中广泛使用的T-700碳纤维性能进行了比较。实验数据表明，PBO纤维在高性能纤维中强度最高。但PBO纤维复合材料层间剪切强度低于芳纶纤维复合材料，这是由于PBO纤维未经表面处理，纤维表面的活性低而且较光滑所致。     

Sinomenine Hydrochloride Promotes TSHR-Dependent Redifferentiation in Papillary Thyroid Cancer

Radioactive iodine (RAI) plays an important role in the diagnosis and treatment of papillary thyroid cancer (PTC). The curative effects of RAI therapy are not only related to radiosensitivity but also closely related to the accumulation of radionuclides in the lesion in PTC. Sinomenine hydrochloride (SH) can suppress tumor growth and increase radiosensitivity in several tumor cells, including PTC. The aim of this research was to investigate the therapeutic potential of SH on PTC cell redifferentiation. In this study, we treated BCPAP and TPC-1 cells with SH and tested the expression of thyroid differentiation-related genes. RAI uptake caused by SH-pretreatment was also evaluated. The results indicate that 4 mM SH significantly inhibited proliferation and increased the expression of the thyroid iodine-handling gene compared with the control group (p < 0.005), including the sodium/iodide symporter (NIS). Furthermore, SH also upregulated the membrane localization of NIS and RAI uptake. We further verified that upregulation of NIS was associated with the activation of the thyroid-stimulating hormone receptor (TSHR)/cyclic adenosine monophosphate (cAMP) signaling pathway. In conclusion, SH can inhibit proliferation, induce apoptosis, promote redifferentiation, and then increase the efficacy of RAI therapy in PTC cells. Thus, our results suggest that SH could be useful as an adjuvant therapy in combination with RAI therapy in PTC.     

Mn4+-activated KLaMgWO6: A new high-efficiency far-red phosphor for indoor plant growth LEDs

Novel Mn⁴⁺-activated KLaMgWO₆ red phosphors with different Mn⁴⁺ concentrations were successfully synthesized via a high-temperature solid-state reaction method. The phase formation, microstructure, photoluminescence properties, decay lifetimes and internal quantum efficiency were discussed to analyze the properties of the as-prepared phosphors. The samples belonged to monoclinic crystal system with enough WO₆ octahedrons that provided suitable sites for Mn⁴⁺ ions. Upon the excitation of 348?nm, KLaMgWO₆:Mn⁴⁺ phosphors gave bright far-red emission around 696?nm due to the ²E_g→⁴A_2g transition of Mn⁴⁺ ions. The critical concentration of Mn⁴⁺ was 0.6?mol% and the concentration quenching mechanism belonged to electric multipolar interaction. Besides, the CIE chromaticity coordinates of the KLaMgWO₆:0.6%Mn⁴⁺ phosphor were (0.7205, 0.2794) which located in deep red range, and its color purity reached up to 96.6%. The KLaMgWO₆:0.6%Mn⁴⁺ sample also exhibited high internal quantum efficiency of 43%. All of the admirable optical properties indicate that the KLaMgWO₆:Mn⁴⁺ phosphors can be applied to indoor plant growth illumination.     

鱼尾型机头中熔体流动的三维流场分析

本文利用ANSYS和MATLAB软件，对鱼尾型片材机头中熔体的速度、压力、剪切应力和粘度的分布进行三维有限元模拟和分析。探知了熔体在流道内的运动规律及特点并分析其原因，对口模设计具有定的指导作用。     

高纯纳米ZnSnO3气敏材料的制备及气敏性能

用草酸-氨水共沉淀法制备了ZnSnO3粉体,适当烧结后制备了一种对乙醇具有高灵敏度和高选择性的传感器。用X射线衍射仪和电镜对其成分和形貌进行分析。此外,用DSC-TG检测了草酸-氨水共沉淀法制得的前驱体反应过程,并与其它方法如：固-固反应、氨水反应制备出的粉体作了比较。结果发现：草酸-氨水共沉淀法制备的前驱体,在600℃,30h热处理后,可以获得高纯纳米ZnSnO3粉末。由这种粉末经700℃烧结2h制成的传感器对乙醇的灵敏度可达13．329。在有其它气体共存时,这种气敏传感器对乙醇具有良好的选择性。在30d的连续检测下,具有很好的稳定性。     

硫酸鱼精蛋白与溴甲酚绿的分光光度研究

在pH 3.95的B-R缓冲溶液中,硫酸鱼精蛋白(Protamine Sulfate,PS)与溴甲酚绿(XJFL)相互作用,在414 nm处有最大吸收峰;研究了酸度、温度、时间、离子强度、表面活性剂等对体系的影响;测出了XJFL与PS反应生成物的线性范围:0～23.63 mg·L-1;计算了表观摩尔吸光系数:ε=16.51 L·cm-1·g-1及离解度:α=0.12;建立了PS的反应体系。