4种丙烯酸酯橡胶结构和性能的对比

对比研究日本产AR74,AR840和国产AR100,AR96四种牌号的丙烯酸酯橡胶(ACM)的结构和性能。结果表明:4种胶均为丙烯酸丁酯橡胶;AR100和AR96的相对分子质量和物理性能相近,生胶拉伸强度和门尼粘度高于AR74和AR840;AR74,AR840,AR96和AR100的玻璃化温度依次升高,热稳定性依次变好;采用相同的皂/硫黄硫化体系时,AR840的硫化程度最高,AR100和AR96硫化胶的物理性能优于AR74和AR840硫化胶。     

共混比对不同耐寒级别ACM并用胶性能的影响

研究了不同耐寒级别ACM（标准型AR801和耐寒型AR840）共混比对并用胶性能的影响。结果表明,随着AR840用量的增加,ML升高,AM下降,拉伸强度和撕裂强度下降,耐油性能下降,玻璃化转变温度和脆性温度下降,并用耐寒型ACM可改善ACM硫化胶的耐低温性能。     

AR—M—AR粉对脲醛树脂增强效果研究

利用AR－M－AR粉对脲醛树脂（UF树脂）进行增强和降低游离甲醛释放量研究结果表明，由羟甲基化三聚氰胺和烷基间苯二酚制成的线型AR－M－AN粉能显著提高UF树脂胶合板的胶接强度，特别是胶合耐水性，并能明显地减少UF树脂胶合板的游离甲醛释放量。但是，对于在强酸性条件下合成的部分UF树脂添加AR－M－AR粉后胶接强度下降。     

AR71与2种国产丙烯酸酯橡胶的对比研究

从相对分子质量、玻璃化转变温度和物理机械性能等方面研究了日本瑞翁公司生产的AR71与国产AR81和AR1000。结果表明,AR71的相对分子质量最高且分布最窄,AR1000的相对分子质量分布最宽。AR71和AR81的玻璃化转变温度接近,但都低于AR1000。AR71生胶门尼粘度最高,AR1000混炼胶门尼粘度最高。炭黑填充AR71的Payne效应最明显,但分散较差。采用皂-硫黄硫化体系时,AR71的硫化程度最高,硫化速度最快,AR81的硫化程度最低。AR71硫化胶的有效阻尼温域最宽,AR1000的最窄。     

魔芋胶的交联化学改性研究

采用三氯氧磷、氯乙酸醚化和卡拉胶复配三种方法对魔芋葡甘聚糖(KGM)进行改性,采用AR500动态流变仪测定了魔芋胶的剪切弹性模量和粘性模量随温度和角频率的变化,并与改性后的样品作了比较。结果显示,不同的改性方法可以有效调控魔芋胶的流变性,使之适应更广泛的技术要求,拓展应用范围。     

粘接技术在电厂设备检修中的应用

粘接技术现已广泛应用于国民经济各个部门。近年来,我厂在检修工作中大胆采用粘接技术,取得了可喜的经济、技术效益。下面,分别将使用氧化铜无机胶、C-4无机胶以及AR—5耐磨胶的情况介绍如下: 一、氧化铜无机胶氧化铜无机胶(YW-1无机胶或CPS氧化铜无机胶)是一种高强度、耐高温的无机结构胶。使用它与传统的铆、焊等机械联接法比较,具有工艺简单、使用方便、成本低,可联接各种不同的金属材料、接头处力分布均匀等优点。在一定的工艺条件下,使用它能获得很高的粘接强度,且耐高、低温,     

间苯二酚-甲醛树脂AR50在全钢载重子午线轮胎带束层中的应用

研究新型间苯二酚-甲醛树脂AR50在全钢载重子午线轮胎带束层中的应用。结果表明,新型间苯二酚-甲醛树脂AR50等量替代间苯二酚后胶料的t₁₀延长约16%,有效提高了操作安全性,且有利于胶料中游离硫与钢丝帘线镀层中铜的界面粘合;硫化胶的定伸应力略增大,拉伸强度和拉断伸长率有所减小;耐热空气老化性能和耐疲劳性能更佳;粘合胶与钢丝帘线的初始粘合力提高了约7%,热氧老化后、湿热老化后和动态老化后的抽出力保持率均提高了约2%,盐水老化后的抽出力保持率相当。且加入间苯二酚-甲醛树脂AR50的胶料在混炼过程中,基本消除了烟雾和刺激性气味,大大改善了操作员的环境。     

用调和自制铁粉的502瞬间胶修补机床导轨拉伤面

我厂从1984年开始采用调和自制280目铸铁粉或还原铁粉的502瞬间胶修补拉伤导轨,取得了十分理想的效果。与我厂曾使用过的烧银焊、锡铋合金钎焊、巴氏合金焊、AR—4或AR—5耐磨胶修补的方法相比,该工艺更加实用。现将该工艺介绍如下。一、502瞬间胶特性及自制铁粉的加工 1、502瞬间胶的特性 502瞬间胶为无色透明液体,渗透性强,使用方便;粘接强度高,室温剪切强度达9.8MPa;固化快速,室温几秒钟到几分钟     

粘接技术在机械工业中的应用(续)

八、机械维修在机械产品的维修中,用粘接技术解决问题,常遇到磨损、破裂和自身缺陷方面的较多。1、机床导轨因工作运动磨擦,会产生拉毛、划伤或凹陷等磨损现象,可用多种粘接方法修复。对拉伤等部位铲成平底或尖底沟,除去油污。将胶涂布于沟槽中,稍高于工作面,完全固化后刮平。常用的胶粘剂为耐磨性胶如 AR 型耐磨胶、HNT 耐磨涂料或加进耐磨填料的自制环氧树脂类胶粘剂。2、对磨损面大而严重的导轨面可采用     

AR-4耐磨胶在我厂设备维修上的应用

在设备维修中,人们经常会遇到表面被磨损的零件,如轴、孔、机床导轨等。为了恢复这些零件原来的几何形状,尺寸规格,通常采用电镀、焊补或镶套等工艺。但这些工艺较复杂,费工又费时,因而检修工人迫切需要一种较简便的修复工艺。随着科学技术的发展,湖北省襄樊市生物化学研究所研制的AR—4耐磨胶粘剂(以下简称“耐磨胶”),就是一种简便易用的修补材料。耐磨胶分甲、乙两种组份,使     

丙烯酸树脂及其复合材料热降解动力学研究

采用热重分析仪研究了丙烯酸树脂(AR)和粒径不同玻璃纤维/丙烯酸树脂(GF/AR)复合材料的热降解过程,比较了不同粒径的GF对AR复合材料的热稳定性和其热降解过程的影响,并结合扫描电镜表征了其微观形貌。采用Kissinger法和Flynn-Wall-Ozawa法计算了AR和GF/AR复合材料的热降解动力学活化能,并运用Coats-Redfern法确定了AR和GF/AR复合材料对应的热降解反应机理函数。结果表明:AR和GF/AR复合材料呈现出相似的热分解阶段,GF有助于提高材料的热稳定性且与基体结合较好、分散较均匀;通过不同的计算方法获取了相应的活化能并确定了相应的机理函数。     

On backward periodic autoregressive processes

It has been shown that there is a one-to-one correspondence between a multivariate autoregress ive (AR) process and a scalar periodic AR process. So we can analyze periodic processes by the theory of multivariate AR processes and vice versa.
Multivariate AR processes have been widely studied and the Levinson–Whittle–Wiggins–Robinson algorithm is well known for obtaining the predictor coeffic ient matrices. In addition, the circular Levinson algorithm has been derived for obtaining the coefficients of periodic AR processes.
In this paper, we construct backward periodic AR processes from the auxiliary coefficients used in this algorithm. A numerical example is also presented and the statistical properties of the estimated coefficients of backward periodic AR processes based on a sample of finite size are derived.     

Filling the gap between Continuous and Discrete Time Dynamics of Autoregressive Processes

Discretization of continuous time autoregressive (AR) processes driven by a Brownian motion and embedding of discrete time AR sequences driven by a Gaussian white noise are classical issues. The article aims at establishing and using such discretization and embedding formulae between extended AR continuous time processes and discrete time sequences. The continuous-time processes are driven by either Brownian or jump processes, and may have random coefficients depending on time; Lévy-driven processes are also considered. The innovation of the discrete time processes may be of many types – including Gaussian. In one way, observing the continuous time AR process at discrete times leads the AR dynamics of the discretized process to be characterized. The other way round, AR sequences can be embedded, in the almost sure sense, into continuous time AR processes with the same dynamics. Illustration is provided through many examples and simulation.     

Investigating color appearance in optical see‐through augmented reality

Color appearance for real objects has been studied over decades and it has been well modeled. However, in augmented reality (AR) environments, virtual content is added to a real background and a mixed appearance is perceived. In this research, we studied color appearance in AR and investigated the applicability of the CAM16 color appearance model, one of the most comprehensive current color appearance models, in an AR environment. Using a benchtop optical mixing apparatus as an AR simulator, objective measurements of mixed colors in AR were performed. Then a psychophysical color matching experiment was performed with combinations of mixed foreground and background colors. The results showed that CAM16 is not accurate in predicting the color appearance in AR environment; therefore, it was modified with the addition of chromatic simultaneous contrast, resulting in an improved fit to the AR experiment data. A second psychophysical color matching experiment was performed on a single display to compare the color perception in AR with color perception in real world from a single display.     

Cell Adhesion Regulates Expression of the Androgen Receptor and Coregulators in Different Prostate Cancer Cells

Prostate cancer cells adhere to a tumor basement membrane, while secretory epithelial cells reside in a suprabasal cell compartment. Since tumor cells are derived from suprabasal epithelial cells, they experience de-novo substratum adhesion in the context of oncogenesis. We therefore analyzed whether cell-matrix adhesion could affect the protein expression and activity of the AR. In this study, AR protein expression declined upon suspension of BPH-1-AR cells, but not in PC-3-AR cells shown by Western blot. In a time course study, BPH-1 cell lost AR expression within 6 hours, and the synthetic androgen, R1881 reduced the loss of AR expression. We further explored the mechanism of AR loss in suspended BPH-1 cells. BPH-1-AR cells underwent apoptosis (anoikis) when suspended for 2 – 5 hours. Suspension did not induce significant apoptosis or decreasing of AR expression in PC-3 cells. Inhibition of apoptosis in suspended BPH-1-AR cells, either by expression of Bcl-2 or Bcl-xl or by treatment with Z-VAD, a caspase inhibitor, prevented loss of AR protein. In contrast, the calpain protease inhibitor, ALLN, accelerated the loss of AR protein expression. Additionally, cell-matrix adhesion changed the expression of coregulators of AR in the mRNA level of prostate cancer cells. Our results demonstrate that AR protein expression was reduced through activation of cell death pathways, and thus indirectly through cell suspension in BPH-AR cells. The activity of AR can also be regulated by adhesion in PC-3-AR and LNCaP cells through affecting the coregulators level.     

热处理工艺对减反膜性能的影响

以本实验室制备的高性能减反膜为研究对象,利用溶胶一凝胶法合成SiO：溶液,采用高速旋涂法制备纳米多孔SiO2减反膜,测试结果表明涂覆在白玻基材上的减反膜在可见光波段（400～800nm）范围内的透过率为94．6％±0．3％,其在405nm波长处的透过率达到1198．27％;同时进一步研究了热处理工艺在减反膜涂覆阶段对其减反性能的影响,研究发现：如果在基材表面涂覆一定厚度的减反膜,不同的热处理工艺对其的减反效果影响很大;如果热处理工艺选择不当,会使最终得到的涂层失去减反效能,甚至大幅度降低基材本身的透过率,为84．9％±1．1％。     

Improving Strategies in the Development of Protein-Downregulation-Based Antiandrogens

The androgen receptor (AR) plays a crucial role in the occurrence and development of prostate cancer (PCa), and its signaling pathway remains active in castration-resistant prostate cancer (CRPC) patients. The resistance against antiandrogen drugs in current clinical use is a major challenge for the treatment of PCa, and thus the development of new generations of antiandrogens is under high demand. Recently, strategies for downregulating the AR have attracted significant attention, given its potential in the discovery and development of new antiandrogens, including G-quadruplex stabilizers, ROR-γ inhibitors, AR-targeting proteolysis targeting chimeras (PROTACs), and other selective AR degraders (SARDs), which are able to overcome current resistance mechanisms such as acquired AR mutations, the expression of AR variable splices, or overexpression of AR. This review summarizes the various strategies for downregulating the AR protein, at either the mRNA or protein level, thus providing new ideas for the development of promising antiandrogen drugs.