Effect of Self-adhesive Resin Cement and Tribochemical Treatment on Bond Strength to Zirconia

Aim To evaluate the interactive effects of different self- adhesive resin cements and tribochemical treatment on bond strength to zirconia. Methodology The following self-adhesive resin cements for bonding two zirconia blocks were evaluated： Maxcem （MA）, Smartcem （SM）, Rely X Unicem Aplicap （UN）, Breeze （BR）, Biscem （BI）, Set （SE）, and Clearfil SA luting （CL）. The specimens were grouped according to conditioning as follows： Group 1, polishing with 600 grit polishing paper; Group 2, silica coating with 110 μm Al2O3 particles which modified with silica; and, Group 3, tribochemical treatment - silica coating ＋ silanization. Specimens were stored in distilled water at 37℃ for 24 hours before testing shear bond strength. Results Silica coating and tribochemical treatment significantly increased the bond strength of the MA, UN, BR, B1, SE and CL to zirconia compared to #600 polishing. For both #600 polished and silica coating treatments, MDP- containing self-adhesive resin cement CL had the highest bond strengths to zirconia. Conclusion Applying silica coating and tribochemical treatment improved the bond strength of self-adhesive resin cement to zirconia, especially for CL.

Virus-phytoplankton adhesion:a new WSSV transmission route to zooplankton

The pathogenicity of white spot syndrome virus （WSSV） to zooplankton species, rotifer Brachionus urceus （Linnaeus）, copepod Acartia clausi （Giesbrecht） and mysid shrimp Neomysis awatschensis （ Brandt ）, was estimated by immersion challenge and virus - phytoplankton adhesion mute to investigate a potential new transmission mute of WSSV to zooplankton. WSSV succeeded in infecting these zooplankton species and nested-PCR revealed positive results for the virus - phytoplankton adhesion mute, whereas WSSV cannot infect zooplankton by immersion challenge. These results indicated that virus - phytoplankton adhesion route is a successful new transmission mute of WSSV to zooplankton and also implied that phytoplankton could be a carrier in WSSV transmission.

One-pot preparation and applications of self-healing,self-adhesive PAA-PDMS elastomers

A new family of transparent,biocompatible,self-adhesive,and self-healing elastomer has been developed by a convenient and efficient one-pot reaction between poly(acrylic acid)(PAA)and hydroxyl-terminated polydimethylsiloxane(PDMSOH).The condensation reaction between PAA and PDMS-OH has been confirmed by attenuated total reflection Fourier transform infrared(ATR-FTIR)spectra.The prepared PAA-PDMS elastomers possess robust mechanical strength and strong adhesiveness to human skin,and they have fast self-healing ability at room temperature(in^10 s with the efficiency of 98%).Specifically,strain sensors were fabricated by assembling PAA-PDMS as packaging layers and polyetherimide-reduced graphene oxide(PEI-rGO)as strain-sensing layers.The PAA-PDMS/PEI-rGO sensors are stably and reliably responsive to slight physical deformations,and they can be attached onto skin directly to monitor the body’s motions.Meanwhile,strain sensors can self-heal quickly and completely,and they can be reused for the motion detecting after shallowly scratching the surface.This work provides new opportunities to manufacture high performance self-adhesive and self-healing materials.

The Crack Self-healing Properties of Cement-based Material with EVA Heat-melt Adhesive

An experimental program was carried out to investigate whether EVA （ethylene vinyl acetate copolymer） heat-melt adhesive can potentially act as a self-healing agent in cement-based material. The effects of incorporation of EVA and heating on the properties of mortar were studied. Self-healing capacity of EVA specimens was also verified. The experimental results show that the addition of EVA would not greatly affect original characteristics of the matrix when EVA content was less than 5%; the interface between EVA and cement matrix was well improved after heating, which allows a significant improvement in flexural strength and toughness of specimen; pre-damaged specimens in various degrees （30%, 50% and 70%） were effectively repaired by EVA and the repair efficiency all exceeded 100%.

Adhesive Bonding and Self-Curing Characteristics of α-Starch Based Composite Binder for Green Sand Mould/Core

Interactions between different components in α-starch based composite binder for green sand mould/core were investigated by using XRD, IR spectra, 1H NMR spectra and SEM. Several adhesive hardening structures and theories of the binder at room temperature were proposed according to the interactions between various compositions. Thus, the reasons for the binder to have excellent combination properties and unique adhesive bonding and self-curing characteristics were explained by these theories successfully. And the theories are of great directive importance to design and development of composite binder for green sand mould/core.

Synthesis of Ecofriendly Self-crosslinking Adhesive and Its Application in Pigment Printing

Glycidyl acrylate was synthesized successfully utilizing phase - transfer catalyst and was applied to emulsion polymerization of acrylates as the crosslinking agent. Combined with other two kinds of crosslinking agents, a new type of ecofriendly self - crosslinking adhesive was prepared . Factors affecting the preparation such as reaction temperature, initiator, eniulsifiers, reaction time and so on were studied comprehensively. Properties in relation to pigment printing of the prepared adhesives were also tested and compared with two kinds of commercial adhesives that have been widely applied in printing industry.

Improvement of Interfacial Adhesion Strength and Thermal Stability of Cu/p-SiC:H/SiOC:H Film Stack by Plasma Treatment on the Surface of Cu Film

A highly reliable interface of self-aligned barrier CuSiN thin layer between the Cu film and the nano-porous SiC：H （p-SiC：H） capping barrier （k=3.3） has been developed in the present work. With the introduction of self-aligned barrier （SAB） CuSiN between a Cu film and a p-SiC：H capping barrier, the interfacial thermal stability and the adhesion of the Cu/p-SiC：H film are considerably enhanced. A significant improvement of adhesion strength and thermal stability of Cu/p-SiC：H/SiOC：H film stack has been achieved by optimizing the pre-clean step before caplayer deposition and by forming the CuSiN-like phase. This cap layer on the surface of the Cu can provide a more cohesive interface and effectively suppress Cu atom migration as well.

Effect of Different Pretreatments to Post-space on Bonding Strength of Fiber Posts Luted with a Self-adhesive Resin Cement

The effects of different post-space pretreatments on the retentive force of fiber posts cemented with a self-adhesive resin cement were investigated. Twenty-eight single-canal premolars were obturated by Resilon using warm vertical compaction and treated with distilled water, 2.5% NaOCl, 17% EDTA and 2.5% NaOCI; or 17% EDTA, 2.5% NaOCI, and ultrasonic agitation （U/E/N treatment）. Subsequently, radicular dentin surfaces were observed under scanning electron microscopy （SEM）. RelyX Fiber Posts were cemented in the treated canals by using RelyX U100, and thin-slice push-out test and SEM observation of coronal and apical regions of the specimens were performed. Data were analyzed using two-way ANOVA and Tukey＇s HSD post- hoc tests, and the percentage of failure type was calculated. Ultrasonic/EDTA/NaOC1 irrigation showed the maximum effectiveness in removing the smear layer and debris on the dentin surface. The apical bond strength of the experimental groups was significantly higher than that of the control group （P〈 0.05）. Adhesive failure between cement and dentin was the most common mode of failure. No obvious RDIZ or resin tag was detected. Chemical irrigants facilitated the bonding of these fiber posts, and ultrasonic activation improved retention. Future studies should evaluate the effectiveness of irrigation on fiber post push-out strength in fatigue cycling condition.

连接方式对HC420/780DP-AA6063接头剪切拉伸性能的影响

通过剪切拉伸试验研究了HC420/780DP钢与AA6063挤压铝合金胶接、自冲铆接、螺栓连接、胶铆连接及胶螺连接接头的剪切拉伸性能,结果表明:自冲铆接和螺栓连接会破坏板材的完整性,剪切拉伸过程中铆钉或螺栓与板材接触位置发生应力集中,导致裂纹萌生、扩展,最终铆钉拉脱或AA6063挤压铝合金撕裂;结构胶增大了钢/铝接头的受力面积,剪切拉伸过程中强度较低的AA6063挤压铝合金发生断裂;胶接、胶铆连接、胶螺连接接头最大剪切载荷基本一致,但胶铆连接、胶螺连接接头吸收的能量与胶接接头相比分别增大了11.8%和8%;当钢/铝接头处于仅受剪切拉伸载荷的服役环境时,可考虑单独使用结构胶进行连接,无需额外使用自冲铆接或螺栓连接。

Diels-Alder型自修复聚氨酯胶粘剂的制备及其性能

目前,针对珍贵零件粘接后难以回收重复使用的问题,将可逆共价键引入胶粘体系成为解决问题的方向。研究使用糠醇(FA)和N,N′-(4,4′-亚甲基二苯基)双马来酰亚胺(BMI)制备了含有Diels-Alder(DA)键的二元醇(DA diol),使用六亚甲基二异氰酸酯(HDI)分别与聚四氢呋喃二醇(PTMG-2000)和DA diol反应封端,最后使用1,1,1-三(羟甲基)丙烷(TMP)与封端产物反应形成交联结构的聚氨酯材料(DPU)。结果表明,DPU具备优异的机械性能、热稳定性和粘接性能。DA键在DPU中具有可逆性且DA逆反应(r-DA)的最佳温度为135℃。DA键含量最多的DPU-Ⅳ的修复效率最高可达到89.0%。DPU-Ⅲ、DPU-Ⅳ粘接性能优异,对不锈钢粘接的剪切强度分别可达到(6.41±0.41)和(2.89±0.34)MPa;DPU-Ⅳ具有重复粘接使用的能力,对不锈钢基材重复粘接的3次的剪切强度分别为(2.89±0.34)、(1.91±0.15)和(1.68±0.20)MPa。粘接性能测试体现出胶膜自身强度与粘接的剪切强度、修复效率与重复粘接能力间的相关性。

Numerical Analysis of the Adhesive Forces in Nano-Scale Structure

Nanohairs, which can be found on the epidermis of Tokay gecko＇s toes, contribute to the adhesion by means of van der Waals force, capillary force, etc. This structure has inspired many researchers to fabricate the attachable nano-scale structures. However, the efficiency of artificial nano-scale structures is not reliable sufficiently. Moreover, the mechanical parameters related to the nano-hair attachment are not yet revealed qualitatively. The mechanical parameters which have influence on the ability of adhesive nano-hairs were investigated through numerical simulation in which only van der Waals force was considered. For the numerical analysis, finite element method was utilized and van der Waals force, assumed as 12-6 Lennard-Jones potential, was implemented as the body force term in the finite element formulation.

一步法快速制备Mg^(2+)-壳聚糖/聚丙烯酰胺多功能复合水凝胶

文中采用一步法制备了具有黏附性、导电性、应变传感性能和自愈性的Mg^(2+)-壳聚糖(CS)/聚丙烯酰胺(PAM)双网络复合水凝胶。将Mg^(2+)直接加入到水凝胶反应体系中,原位形成金属离子交联键,避免了复杂的浸泡过程;此外,采用紫外光引发比热引发聚合更方便快捷。Mg^(2+)-CS/PAM水凝胶与多种材料具有较强的黏附能力,如橡胶、玻璃、塑料、金属、皮肤和石头等,其中与橡胶表面的黏附强度为32.09 kPa。由于其中丰富的自由离子,Mg^(2+)-CS/PAM水凝胶表现出良好的导电性和应变敏感性,可用于监测人体的大运动和细微运动。而且切割后的水凝胶在室温4 h内可完全愈合,还能拉伸至原来长度的4倍。

Parameter Self - Learning of Generalized Predictive Control Using BP Neural Network

This paper describes the self—adjustment of some tuning-knobs of the generalized predictive controller(GPC).A three feedforward neural network was utilized to on line learn two key tuning-knobs of GPC,and BP algorithm was used for the training of the linking-weights of the neural network.Hence it gets rid of the difficulty of choosing these tuning-knobs manually and provides easier condition for the wide applications of GPC on industrial plants.Simulation results illustrated the effectiveness of the method.

Self - Crosslinking Behavior of Self - Emulsion Water - Based Polyure-thane Coating Agents

The relation between structures and properties of polyurethane are investigated by modern physical and chemical methods.The results obtained are as follows:the effects of the content of self-crosslinking agent on the properties of polyurethane,i.e.,dispersion stability,dynamical viscoelasticity and mechanical properties are discussed.It is found that the optimum molar ratio of epichlorohydrin and diethylenetriamine is 1:2.A mois-

Culture Self- Consciousness in Transmission of Chinese Philosophy from the Perspective of English Globalization -- Taking the Belt and Road Initiative for Example

The Belt and Road Initiative contains the aspiration of Chinese nation to pursue ideological freedom and desire of strengthening international exchanges and cooperation. This paper takes the Belt and Road Initiative for example,emphasizing the interpretation of the inheritance and development of Chinese culture so as to study the importance of Culture Self-Consciousness in Chinese Philosophy,in the context of English globalization. That is to say,this paper stresses the spirits and the stand of nation 's demonstration on pursuing peace,cooperation and sustainable development in the civilization continuity from traditional China to the contemporary China,with practical philosophic view.

植物油微胶囊沥青混合料的微观力学性能及自愈合机制

为了研究植物油微胶囊沥青混合料的微观力学性能及自愈合机制,利用分子动力学方法基于12分子沥青模型构建沥青微裂缝模型,采用植物油提取物油酸、亚油酸以及石油基再生剂乙基四氢化萘作为芯材,探究三种芯材释放后沥青微裂缝的自愈合进程,计算沥青分子的自扩散系数并分析不同芯材的作用机制,同时构建沥青-集料模型,采用粘聚能、粘附能、粘附强度等指标分析融入不同芯材后沥青-集料界面的微观力学性能。结果表明:芯材的释放加速了沥青分子的自扩散,提高了微裂缝的自愈合能力,且微裂缝自愈合能力随温度的升高而增强;与芯材融合后老化沥青的粘聚能和粘附能分别提高了37.2%和36.8%以上,并且老化沥青-集料界面的粘附强度增加;与石油基再生剂相比,植物油能更好地促进微裂缝的愈合。通过分子动力学技术可以更深入地探查微胶囊沥青路面的自愈合机制,从而为微胶囊芯材的设计与选择提供可行的方法。

基于动态亚胺键结合的自粘附纳米纤维素-明胶离子传导凝胶的构建与性质

聚合物水凝胶通常具有优异的亲水性、粘附性、导电性等性能,可广泛应用于柔性传感、药物输送、环境等领域。针对天然高分子水凝胶存在的力学性能、导电性能等的不足,采用将含醛基的纳米纤维素与含氨基的明胶进行结合以形成动态亚胺键,并通过引入纳米蛭石形成的快速离子传输通道,以改善天然聚合物水凝胶的离子导电性。其次,采用物理共混方法将单宁酸引入到凝胶体系中,形成多重氢键网络,进一步提高凝胶的力学性能。同时,得益于单宁酸自身的儿茶酚结构能够与不同表面形成可逆非共价相互作用,从而赋予了凝胶优异的自粘附能力。结果表明:纳米纤维素-明胶离子传导凝胶的拉伸强度达到43.35kPa,应变提高了50倍,较未添加纳米蛭石凝胶提高了300%,弹性模量达到2870kPa,较未添加纳米蛭石凝胶提高了18倍,导电性能提高了92.4%,可作为柔性传感器用于人体运动监测,在智能可穿戴设备领域具有良好的应用潜力。

基于最小二乘法的不干胶材料柔性版印刷网点增大及补偿研究

不干胶材料印刷品通常采用柔性版印刷,其印刷网点的变化影响着不干胶材料上图像复制的质量,因此需要进行网点增大补偿。本研究设计了柔性版印刷测试版,获取了不同印刷条件下的网点增大数据,基于最小二乘法,借助Matlab软件拟合了网点增大曲线,对比分析了印版硬度、印刷压力和加网线数对网点增大的影响。同时采用“网点实际增大补偿”算法对网点增大进行了补偿,并对补偿效果进行了模拟验证。研究结果表明,镜面铜版纸不干胶材料在柔性版印刷时应选用硬度偏大、加网线数适中的柔性版,并在尽可能小的印刷合压量条件下印刷;采用“网点实际增大补偿”算法对网点增大进行补偿,能较好地控制网点增大,还原印刷阶调。

三种不同树脂粘结系统对纤维桩粘结效果的影响

目的评价全酸蚀粘结系统、自酸蚀粘结系统及自粘结树脂对纤维桩粘结效果的影响。方法选取2021年10月至2022年3月于泰州职业技术学院口腔门诊部行前牙纤维桩修复的82例患者(共122颗前牙)作为研究对象,按照不同树脂粘结系统将其分为全酸蚀组(28例,40颗)、自酸蚀组(26例,40颗)及自粘结组(28例,42颗)。全酸蚀组使用Tetric-N Bond全酸蚀树脂粘结剂对纤维桩进行粘结,自酸蚀组使用All-Bond Universal自酸蚀树脂粘结剂对纤维桩进行粘结,自粘结组使用Relyx Unicem自粘结树脂对纤维桩进行粘结,完成纤维桩粘结后行全瓷冠修复。比较三组纤维桩核的稳固率及全瓷冠修复体的红色美学指数(PES)、白色美学指数(WES)评分。结果粘结6、12、18个月后,三组纤维桩核的稳固率组间及组内比较,差异无统计学意义(P>0.05)。粘结18个月后,三组全瓷冠修复体的PES、WES评分比较,差异无统计学意义(P>0.05)。结论三种树脂粘结系统对纤维桩的粘结效果在短期内相当,远期效果还需进一步的观察。

基于肟-氨基甲酸酯的超强自修复水性聚氨酯胶粘剂的制备及性能分析

基于肟-氨基甲酸酯热可逆成键原理,利用可工业批量获得的二甲基乙二肟为构建单元,设计合成了一类具有高强动态网络结构的水性乳液,制备出综合性能与重复利用兼顾的聚氨酯胶粘剂;通过变温红外光谱结合差式扫描量热仪分析了肟-氨基甲酸酯升温过程的可逆成键特性,并利用动态力学谱仪对变温过程的网络松弛行为进行了研究.结果表明,合理的硬段含量与结构设计赋予了胶粘剂极高的粘结强度(25 MPa,一般商业通用热熔胶的粘结强度<6 MPa)、优异的乳液稳定性(粒径<100 nm)以及接近97%的修复效率(160℃,10 min下的剪切搭接实验).该类乳液具有超强、稳定及工艺可放大等特性,为水性自修复胶粘剂的商业化开发提供了新途径和新思路.