PVC/PVDF/CPE共混体系研究

以ＣＰＥ作为ＰＶＣ／ＰＶＤＦ的增容剂,研究了ＰＶＣ／ＰＶＤＦ／ＣＰＥ三元共混新体系。对不同组成的共混物的物理机械性能进行测试,分析了讨论了ＰＶＤＦ／ＣＰＥ的增韧效果和机理。结果表明：ＣＰＥ对ＰＶＣ／ＰＶＤＦ共混体系有明显的增容作用,ＰＶＤＦ／ＣＰＥ并用对增韧ＰＶＣ有显著的协同效应。     

反应挤了HDPE／PET共混合金结构与性能研究

采用ＤＳＣ、ＷＡＸＤ、ＳＥＭ及ＴＧＡ等方法研究了ＨＤＰＥ／ＰＥＴ共混合金在增溶剂Ｅ／ＶＡＣ或Ｅ／ＡＡ作用下的结晶性、形态结构及热稳定性。结果表明，Ｅ／ＶＡＣ或Ｅ／ＡＡ的加入，使ＨＤＰＥ／ＰＥＴ体系中ＨＤＰＥ组分的熔融热焓降低，结晶度下降，但熔融峰位置和晶胞基本保持不变；从ＳＥＭ照片可以观察到Ｅ／ＶＡＣ、Ｅ／ＡＡ对共混体系具有一定的增容作用，Ｅ／ＡＡ和效果优于Ｅ／ＶＡＣ；共混体系的热稳定性随Ｅ／ＶＡ     

偏氯乙烯悬浮共聚过程中蒸汽压变化的研究

研究了ＶＤＣ／ＭＭＡ和ＶＤＣ／ＡＮ悬浮共聚过程中蒸汽压的变化。结果表明：该两个共聚体系的蒸汽压—聚合时间关系可分为三个阶段,第一阶段迅速升压,第二阶段缓慢升压,第三阶段显著降压;由于ＡＮ部分地溶于水,使ＶＤＣ／ＡＮ悬浮共聚的第二阶段压力变化很小;ＶＤＣ／ＭＭＡ悬浮共聚约在转化率为７０％时开始降压;ＶＤＣ／ＡＮ悬浮共聚约在转化率为６５％时开始降压     

HDP—PVC／ABS合金材料的研究

研究了高聚合度聚氯乙烯（ＨＤＰ－ＰＶＣ）／ＡＢＳ二元体系力学性能以及添加第三组分对合金材料力学性能的影响。结果表明：ＨＤＰ－ＰＶＣ／ＡＢＳ配比为１００／２５时,共混物的综合性能好,体系能形成较完善的海岛结构;ＨＤＰ－ＰＶＣ／ＡＢＳ／ＭＢＳ体系中,ＭＢＳ能改善多元体系的界面性能,提高合金材料的综合性能;ＨＤＰ－ＰＶＣ／ＡＢＳ／ＣＰＥ体系中,ＣＰＥ能使形成网状结构和海岛结构共存的合金体系,提高合金材料     

PVDF/炭黑导电复合材料的PTC性能研究

研究炭黑种类和用量及ＰＶＤＦ种类对ＰＶＤＦ／炭黑导电复合材料ＰＴＣ特性的影响。结果表明,大粒径、比表面积小的Ｎ７６５炭黑填充导电复合材料的ＰＴＣ性能较好,出现ＰＴＣ现象的炭黑用量范围大;随着ＰＶＤＦ分子量的增大,ＰＶＤＦ／Ｎ７６５炭黑导电复合材料出现最大ＰＴＣ强度的炭黑用量减少,最大ＰＴＣ强度也随之增大。     

DVD光学头结构方案的分析和比较

为了实现高密度存储,ＤＶＤ盘片使用波长为６５０／６３５ｎｍ的激光且物镜ＮＡ应大于０．６。而ＣＤ则使用７８０ｎｍ的激光且数值孔径约为０．４。为了能与ＣＤ类光盘兼容,ＤＶＤ播放器／驱动器中除了要有完成ＣＤ为类盘片的解码电路外,其光学头也需能同时读取ＣＤ盘片。本文分析了目前已经实用的兼容ＣＤ的ＤＶＤ光学砂设计并比较了它们的优缺点。     

SiC-CVD过程的人工神经网络建模

ＳｉＣ－ＣＶＤ过 本质复杂性制约 了碳／碳复合材料表面有效地制备高性能抗氧化涂层。本研究在对ＣＶＤ工艺过程及机理试验研究的基础上,采用人工神经网络技术对ＳｉＣ－ＣＶＤ过程进行了辨识与模拟研究,建立了ＳｉＣ－ＣＶＤ过程的神经网络的模型。     

偏氯乙烯/丙烯腈/苯乙烯悬浮共聚合动力学

本文研究了偏氯乙烯（ＶＤＣ）／丙烯腈（ＡＮ）／苯乙烯（Ｓｔ）三元悬浮共聚合体系的聚合机理、共聚速率、非聚物组成及其特性粘度的影响因素。实验表明随着投料配比的改变,可分成四个不同聚合机理区域。Ｓｔ对ＶＤＣ／ＡＮ／Ｓｔ三元悬浮共聚有缓聚作用。ＶＤＣ三元悬浮共聚速率可用半经验模型,ｄＣ／ｄｔ＝αＣ＾β「Ⅰ」ｏ＾γｅｘｐ（－γｋｄｔ）描述,由实验得到模型参数γ值为２．２４,模型参数α、β是聚合温度与引发剂浓度的函数。ＶＤＣ－ＡＮ－Ｓｔ三元悬浮共聚物存在着较宽的ＶＤＣ组成分布,并受到单体ＡＮ水溶性的影响,经ＡＮ动态相平衡校正后,可预测ＶＤＣ三元共聚物组成。ＶＤＣ－ＡＮ－Ｓｔ共聚物的特性粘度随着转化率的升高而增大。在相同引发剂用量下,高转化率ＶＤＣ－ＡＮ－Ｓｔ共聚物特性粘度的对数与温度的倒数成线性关系。     

E/VAC与马来酸酐反应挤出接枝的研究

用同向双螺杆挤出机进行Ｅ／ＶＡＣ熔融接枝ＭＡＨ的反应。考察了单体、引发剂用量和加工条件对接枝率及熔体流动速率的影响。结果表明,在Ｅ／ＶＡＣ接枝ＭＡＨ的反应中,接枝率随着ＤＣＰ用量、ＭＡＨ用量以及螺杆转速的增加出现峰值,较佳的实验配方为Ｅ／ＶＡＣ：ＭＡＨ：ＤＣＰ＝１００：２：０．２。接枝反应对Ｅ／ＶＡＣ的流动性有很大影响,接枝物的熔体流动速率随ＤＣＰ用量的增加而下降。     

CPE增容PVC／EPDM共混体系力学性能研究

以聚氯乙烯（ＰＶＣ）为主体材料，新型三元乙丙橡胶（ＥＰＤＭ）为改性剂，氯化聚乙烯（ＣＰＥ）为增容剂进行共混，来改善ＰＶＣ的抗冲击性能。实验结果表明，ＰＶＣ和一定量的ＣＰＥ、ＥＰＤＭ共混改性后，共混体系的冲击强度大幅度提高，ＰＶＣ／ＣＰＥ／ＥＰＤＭ在１００／５／１０（Ｗ／Ｗ）时，冲击强度上升值最大，可达４３．７ｋＪ／ｍ＾２，拉伸断裂强度提高近３０％。     

致密工艺对C/C复合材料摩擦性能的影响

采用针刺全炭纤维网胎无纬布整体结构预制体为骨架，经化学气相沉积（CVD）、树脂浸溃（RD固化致密及炭化、石墨化制得C／C复合材料。研究了粗糙层（RL）和树脂炭（RC）对摩擦性能的影响。结果表明，RL结构的C／C复合材料的摩擦性能较好，稳定性较高，是用作飞机刹车材料的前提；采用CVD＋RI制备且石墨化后的C／C复合材料具有优良的摩擦磨损特性；CVD试样的密度较低时，摩擦系数较高，但磨损较大，较难形成完整的摩擦膜。     

Chemical-Vapor-Infiltrated Silicon Nitride, Boron Nitride, and Silicon Carbide Matrix Composites

Composites of carbon/chemical-vapor-deposited (CVD) Si₃N₄, carbon/CVD BN, mullite/CVD SiC, and SiC yarn/CVD SiC were prepared to determine if there were inherent toughness in these systems. The matrices were deposited at high enough temperatures to ensure that they were crystalline, which should make them more stable at high temperatures. The fiber-matrix bonding in the C/Si₃N₄ composite appeared to be too strong; the layers of BN in the matrix of the C/BN were too weakly bonded; and the mullite/SiC composite was not as tough as the SiC/SiC composites. Only the SiC yarn/CVD SiC composite exhibited both strength and toughness.     

Selective catalytic reduction of N2O in industrial emissions containing O2, H2O and SO2: behavior of Fe/ZSM-5 catalysts

The catalytic behavior in N₂O reduction by propane in the presence of O₂, H₂O and SO₂ of Fe/ZSM-5 catalysts prepared by ion exchange and chemical vapour deposition (CVD) is reported. The catalyst prepared by CVD shows a lower dependence of the rate of selective N₂O reduction on the decrease in C₃H₈ to N₂O ratio in the feed and a higher resistance to deactivation by SO₂ in accelerated durability tests with high SO₂ concentration (500 ppm). This catalyst shows stable catalytic behavior in the presence of SO₂ for more than 600 h of time-on-stream. Characterization of the catalysts by UV–VIS–NIR diffuse reflectance indicates that the poor performances of the sample prepared by ion exchange could be related to the presence of highly clustered Fe³⁺ species, in this catalyst. On the other hand, Fe₂O₃ particles are not present in the sample prepared by CVD while mainly isolated Fe³⁺ ions and iron-oxide nanoclusters are present.     

炭布高温预处理对C/C复合材料摩擦磨损性能的影响

采用炭布叠层为坯体，经等温ＣＶＤ工艺制备Ｃ／Ｃ复合材料，并对其摩擦磨损性能进行初步探讨，结果表明，炭布高温预处理能改善Ｃ／Ｃ复合材料的摩擦磨损性能，随着刹车压力的增大，试样的磨损率增大而摩擦系数则减小。     

Selective gas-phase oxidation at oxide nanoparticles on microporous materials

Catalytic oxidation over single metal or bimetallic oxides in nano-size generated on various matrices including zeolite via the chemical vapor deposition (CVD) technique and other methods are reviewed along with other interesting catalytic reactions. Among the various matrices studied, the partially deboronated borosilicate (DBH) played a unique role for the para-selective oxidation of alkylaromatics. The CVD Fe/Mo/DBH activated by the proper calcination procedure exhibited higher catalytic activity, better product selectivity, and superior stability to form aldehydes, in particular, terephthaldehyde and p-tolualdehyde, by the gas-phase O₂ oxidation of p-xylene than its impregnated counterpart and bulk catalytic material. Current mechanistic understanding on the unusual promoting role of CO₂ over the same catalyst was postulated for the O₂ oxidation reaction.

The silica overlayer in nano-size deposited on zeolite by the CVD of silicon alkoxides not only increased the para-selective property, but also provided other useful functions such as control of pore opening and thermal stability of the zeolite catalyst. Other oxidation reactions such as oxidative dehydrogenation of alkylaromatics and alkanes were also reviewed along with the selective N₂O oxidation of benzene to phenol.

CVD Fe/Mo/ZSM-5 oxidized p-xylene to produce aldehydes, but disproportionation and dehydrocoupling of p-xylene to toluene and pseudocuemen, and trimethylbiphenyl-methane, respectively, remained the predominant reactions.     

The improvement of mechanical properties of SiC/SiC composites by in situ introducing vertically aligned carbon nanotubes on the PyC interface

In order to improve the mechanical properties, vertically aligned carbon nanotubes (VACNTs) were in situ introduced on the pyrocarbon (PyC) interfaces of the multilayer preform via chemical vapor deposition (CVD) process under tailored parameters. Chemical vapor infiltration (CVI) process was then employed to densify the multilayer preform to acquire SiC/SiC composites. The results show that the growth of VACNTs on PyC interface is highly dependent to the deposition temperature, time and constituent of gas during CVD process. The preferred orientation and high graphitization of VACNTs were obtained when temperature is 800?℃ and C₂H₄/H₂ ratio is 1:3. The bending strength and fracture toughness of SiC/SiC composites with PyC and PyC-VACNTs interfaces were compared. Compared to the SiC/SiC composite with PyC interface, the bending strength and fracture toughness increase 1.298 and 1.359 times, respectively after the introduction of PyC-VACNTs interface to the SiC/SiC composites. It is also demonstrated that the modification of PyC interface with VACNTs enhances the mechanical properties of SiC/SiC composites due to the occurrence of more fiber pull-outs, interfacial debonding, crack branching and deflection     

Atherogenic Lipoproteins for the Statin Residual Cardiovascular Disease Risk

Randomized controlled trials (RCTs) show that decreases in low-density lipoprotein cholesterol (LDL-C) by the use of statins cause a significant reduction in the development of cardiovascular disease (CVD). However, one of our previous studies showed that, among eight RCTs that investigated the effect of statins vs. a placebo on CVD development, 56–79% of patients had residual CVD risk after the trials. In three RCTs that investigated the effect of a high dose vs. a usual dose of statins on CVD development, 78–87% of patients in the high-dose statin arms still had residual CVD risk. The risk of CVD development remains even when statins are used to strongly reduce LDL-C, and this type of risk is now regarded as statin residual CVD risk. Our study shows that elevated triglyceride (TG) levels, reduced high-density lipoprotein cholesterol (HDL-C), and the existence of obesity/insulin resistance and diabetes may be important metabolic factors that determine statin residual CVD risk. Here, we discuss atherogenic lipoproteins that were not investigated in such RCTs, such as lipoprotein (a) (Lp(a)), remnant lipoproteins, malondialdehyde-modified LDL (MDA-LDL), and small-dense LDL (Sd-LDL). Lp(a) is under strong genetic control by apolipoprotein (a), which is an LPA gene locus. Variations in the LPA gene account for 91% of the variability in the plasma concentration of Lp(a). A meta-analysis showed that genetic variations at the LPA locus are associated with CVD events during statin therapy, independent of the extent of LDL lowering, providing support for exploring strategies targeting circulating concentrations of Lp(a) to reduce CVD events in patients receiving statins. Remnant lipoproteins and small-dense LDL are highly associated with high TG levels, low HDL-C, and obesity/insulin resistance. MDA-LDL is a representative form of oxidized LDL and plays important roles in the formation and development of the primary lesions of atherosclerosis. MDA-LDL levels were higher in CVD patients and diabetic patients than in the control subjects. Furthermore, we demonstrated the atherogenic properties of such lipoproteins and their association with CVD as well as therapeutic approaches.     

Niobic acid and niobium phosphate as highly acidic viable catalysts in aqueous medium: Fructose dehydration reaction

All silicious MCM-41 was investigated as a support or a support precursor for Pd/SiO₂ and prepared catalysts were tested for methanol synthesis from CO and H₂. The methods of Pd loading on the MCM-41 were impregnation, seed impregnation and chemical vapor deposition (CVD). For both impregnations, most Pd existed outside of the pore as large particles, and only a small part of Pd was inserted into the pore of MCM-41 retaining the initial structure. On the contrary, in the catalyst prepared by CVD method, the MCM-41 structure was completely destroyed to become amorphous SiO₂. Yet the average Pd particle size in this catalyst was smaller and its distribution was narrower than those of the catalysts prepared by impregnation methods. In the methanol synthesis from CO hydrogenation the catalyst prepared by CVD showed higher methanol selectivity than other MCM-41-derived catalysts. This result was considered to be due to the more uniform distribution of the Pd particle size.     

气体流速对La／Co／Ni／MgO催化剂CVD法制备碳纳米管的影响

我们在400℃下利用溶胶一凝胶法制备了La／Co／Ni／MgO催化剂,用化学气相沉积法（CVD）在650—600℃下裂解乙炔气体生长碳纳米管,研究了载气、还原气体和碳源气体流速对碳纳米管产量的影响。其中,载气流速N2是100mL／min,还原气体流速H2是30mL／min,碳源气体流速c2H4是60mL／min时,催化剂聚合物团簇分散效果最佳,碳纳米管的产量和形貌达到最大。     

IL-17 Pathway Members as Potential Biomarkers of Effective Systemic Treatment and Cardiovascular Disease in Patients with Moderate-to-Severe Psoriasis

Psoriasis is a chronic inflammatory condition associated with atherosclerotic cardiovascular disease (CVD). Systemic anti-psoriatic treatments mainly include methotrexate and biological therapies targeting TNF, IL-12/23 and IL-17A. We profiled plasma proteins from patients with moderate-to-severe psoriasis to explore potential biomarkers of effective systemic treatment and their relationship to CVD. We found that systemically well-treated patients (PASI < 3.0, n = 36) had lower circulating levels of IL-17 pathway proteins compared to untreated patients (PASI > 10, n = 23). Notably, IL-17C and PI3 were decreased with all four examined systemic treatment types. Furthermore, in patients without CVD, we observed strong correlations among IL-17C/PI3/PASI (r ≥ 0.82, p ≤ 1.5 × 10⁻¹²) pairs or between IL-17A/PASI (r = 0.72, p = 9.3 × 10⁻⁸). In patients with CVD, the IL-17A/PASI correlation was abolished (r = 0.2, p = 0.24) and the other correlations were decreased, e.g., IL-17C/PI3 (r = 0.61, p = 4.5 × 10⁻⁵). Patients with moderate-to-severe psoriasis and CVD had lower levels of IL-17A compared to those without CVD (normalized protein expression [NPX] 2.02 vs. 2.55, p = 0.013), and lower IL-17A levels (NPX < 2.3) were associated with higher incidence of CVD (OR = 24.5, p = 0.0028, 95% CI 2.1–1425.1). As a result, in patients with moderate-to-severe psoriasis, we propose circulating IL-17C and PI3 as potential biomarkers of effective systemic anti-psoriatic treatment, and IL-17A as potential marker of CVD.