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探讨使用不同压力气体吹拂两步法自酸蚀粘接剂对树脂牙本质粘接界面微观形貌及微拉伸粘接强度的影响。20颗离体的完整无龋第3磨牙去除冠釉,按粘接过程中气体吹拂处理方法不同随机分为4组(处理剂和粘合剂均轻吹;处理剂强吹,粘合剂轻吹;处理剂轻吹,粘合剂强吹;处理剂和粘合剂均强吹。轻吹气压为0.1MPa,强吹气压为0.3 MPa),每组5颗牙。各组粘接完成后,37℃水浴24 h,每颗牙切出1片薄片状试件利用场扫描电子显微镜(SEM)观察4组粘接界面微观形貌(n=5),另外每颗牙制成8根长方体形试件测试微拉伸强度(μTBS)(n=40)。SEM观察显示,第1组的粘接剂层最厚,树脂突最短小稀疏;第2组和第3组的粘接剂层较薄,树脂突更长更致密更均匀;第4组的粘接剂层最薄,但是树脂突更长更致密更均匀。第2组的μTBS最高(41.32±3.76)MPa,其次为第3组(31.17±4.80)MPa、第1组(26.24±5.21)MPa,第4组最低(14.89±2.31)MPa。在两步法自酸蚀粘接中,采用气体加压技术吹拂处理剂可显著提高树脂牙本质粘接强度。 相似文献
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北京航空材料研究院研制了一种双组分室温硫化有机硅胶粘剂,工作温度为-60~350℃,颜色为红色或白色,固含量为100%,活性期为1~8h,可以粘接钢、铝、铜、钛合金等金属,也可以粘接硅橡胶和金属,对某些极性高分子材料也可以实现有效粘接。例如粘接硅橡胶和金属,250℃老化200h后室温粘接强度超过2.0MPa,250℃时的粘接强度超过1.0MPa;粘接金 相似文献
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耐350℃有机硅胶粘剂 总被引:1,自引:0,他引:1
北京航空材料研究院研制了一种双组分室温硫化有机硅胶粘剂,工作温度为-60~350℃,颜色为红色或白色,固含量为100%,活性期为1~8h,可以粘接钢、铝、铜、钛合金等金属,也可以粘接硅橡胶和金属,对某些极性高分子材料也可以实现有效粘接。例如粘接硅橡胶和金属,250℃老化200h后室温粘接强度超过2.0MPa,250℃时的粘接强度超过1.0MPa;粘接金 相似文献
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目的对比新型自粘性流动树脂Constic与目前常用的自酸蚀粘结剂搭配普通复合树脂对牙本质的粘接强度,评估自粘性流动树脂Constic的粘接性能能否满足临床需要。方法收集新鲜拔出的人类磨牙60颗,随机分为3组(A组,B组,C组):A组为自粘性流动树脂Constic、B组为一步法自酸蚀粘结剂幻彩-bond搭配普通流动树脂Filtek Supreme XT Flowable、C组为两步法自酸蚀粘结剂Clearfil SE-Bond搭配Filtek Supreme XT Flowable。测试粘接试样剪切粘接强度并对测试结果进行单因素方差分析(one-way ANOVA,LSD)分析。然后在体式显微镜下放大至50倍进行断裂面观察并进行断裂类型统计。结果3组剪切粘接强度分别为:9.15±2.33MPa(A组),10.79±2.37MPa(B组),13.89±2.56MPa(C组)。A组剪切粘接强度与B组之间的差异无统计学意义(P0.05),但均低于C组(P0.05)。A组和B组主要发生的是粘附破坏,C组以混合断裂为主。结论自粘性流动树脂Constic与一步法自酸蚀粘结剂相似,可满足临床需要。 相似文献
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探讨使用不同压力气体喷涂偶联剂对氧化锆表面形貌及氧化锆-树脂粘合剂粘接强度的影响。烧结、喷砂后的氧化锆瓷片,按偶联剂种类(CP;ZP)和喷涂气体压力的高低(L 0.1 MPa;H 0.3 MPa)随机分为CPL、CPH、ZPL、ZPH 4个实验组及无偶联剂处理的对照组NP(n=15)。各组处理后的氧化锆瓷片利用激光共聚焦显微镜观察5组氧化锆表面形貌并测量粗糙度,并与树脂粘合剂(SA luting)粘接并测试微剪切强度。激光共聚焦显微镜观察显示,CPL和ZPL组中氧化锆表面光滑平坦,CPH、ZPH组的氧化锆表面则保留了高低不平的微观形貌,平均粗糙度明显高于低压气体喷涂组。CPH组的微剪切粘接强度最高(24.82±7.34)MPa,其次为CPL组(17.93±1.53)MPa、ZPL组(15.67±3.39)MPa和ZPH组(9.59±5.97)MPa,对照组最低(8.77±3.12)MPa。偶联剂喷涂压力显著影响氧化锆-树脂粘合剂的粘接强度。,, 相似文献
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密封胶的粘接性能直接关系到建筑的防水、防风以及保温效果。为保证不同工况下选出更为合适的建筑用密封胶类型,测试建筑施工密封胶长周期粘接性能是十分必要的。试验选择聚硫密封胶、硅酮密封胶以及聚氨酯密封胶3种作为测试对象,粘接光滑和粗糙2种不同的基体制作试件,将试件放在低湿和高湿2种环境下,通过微控电子拉力机测试密封胶的粘接参数,并计算粘接强度和破坏面积比。结果表明,在低湿环境下,对于粗糙基体,硅酮密封胶的粘接性最佳;对于光滑基体,聚氨酯密封胶的粘接性最佳。在高湿环境下,对于粗糙基体,聚硫密封胶的粘接性最佳;对于光滑基体,硅酮密封胶的粘接性最佳。 相似文献
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MK Uddin AS Juraimi ME Ali MR Ismail 《International journal of molecular sciences》2012,13(8):10257-10267
The main objective of this research was to appraise the changes in mineral content and antioxidant attributes of Portulaca oleracea over different growth stages. The antioxidant activity was measured using 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric-reducing antioxidant power (FRAP) assays. The iodine titration method was used to determine the ascorbic acid content (AAC). DPPH scavenging (IC(50)) capacity ranged from 1.30 ± 0.04 to 1.71 ± 0.04 mg/mL, while the ascorbic acid equivalent antioxidant activity (AEAC) values were 229.5 ± 7.9 to 319.3 ± 8.7 mg AA/100 g, total phenol content (TPC) varied from 174.5 ± 8.5 to 348.5 ± 7.9 mg GAE/100 g. AAC 60.5 ± 2.1 to 86.5 ± 3.9 mg/100 g and FRAP 1.8 ± 0.1 to 4.3 ± 0.1 mg GAE/g. There was good correlation between the results of TPC and AEAC, and between IC(50) and FRAP assays (r(2) > 0.9). The concentrations of Ca, Mg, K, Fe and Zn increased with plant maturity. Calcium (Ca) was negatively correlated with sodium (Na) and chloride (Cl), but positively correlated with magnesium (Mg), potassium (K), iron (Fe) and zinc (Zn). Portulaca olerecea cultivars could be used as a source of minerals and antioxidants, especially for functional food and nutraceutical applications. 相似文献
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采用沉水植物表面流湿地(沉水组)、挺水植物表面流湿地(挺水组)和浮床湿地(浮床组)3种盐沼湿地对长江口近岸低污染水体进行脱氮除磷效能的研究。结果表明,HRT为3 d时,水组、挺水组、浮床组对NO3^--N的去除率在高温时段分别为79.9%±13.2%、71.8%±15.2%、77.2%±13.2%,中温时段分别为39.4%±13.7%、31.5%±8.5%、18.4%±16.6%,低温时段分别为15.6%±14.6%、19.7%±8.6%、2.%5±8.6%。沉水组和挺水组对TP的去除率受温度影响较小,分别为66.4%±32.4%、55.5%±29.4%;而浮床组除磷效果受温度影响较大。当HRT缩短为1.5 d时,3组湿地系统在高温时段仍可达到相近的脱氮除磷效果,在中低温时段脱氮除磷效果都有不同程度的下降。 相似文献
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以丁二烯(Bd)和丙烯腈(AN)为聚合单体,以过硫酸盐为引发剂,以硫醇为相对分子质量调节剂,在10 L聚合釜上采用自由基乳液聚合法合成了AN质量分数为(25±2)%的中腈基含量液体丁腈橡胶。研究了聚合配方及后处理工艺对聚合物性能的影响。结果表明,在聚合反应温度为(30±1)℃;过硫酸盐B 1.5~2.5份,硫醇5~6份,复配阴离子乳化剂A 2~4份;洗涤剂为90℃以上热水,用量为胶浆的1.5倍;干燥温度为(120±5)℃的条件下,可以制得Mn为(1 400±200),AN质量分数为(25±2)%的中腈基含量液体丁腈橡胶。 相似文献
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利用非溶剂相转化法(NIPS),通过在聚偏氟乙烯(PVDF)铸膜液中加入聚二甲基硅氧烷(PDMS),制备了PDMS/PVDF共混疏水微孔膜,并研究了凝胶浴组成(水/乙醇)对铸膜液凝胶动力学、膜形貌、疏水性及力学性能的影响。结果表明,随着凝胶浴中乙醇百分含量由零增加至100 %时,PDMS/PVDF共混膜的断面上指状孔基本消失,海绵状孔结构贯穿断面;当凝胶浴中乙醇含量为100 %时,PDMS与PVDF发生分相;膜表面疏水性能增加,水接触角达到139.68 °;弹性模量、拉伸强度、断裂伸长率分别由(48.06±4.20)、(2.82±0.15) MPa、(92.90±2.53) %下降至(15.70±2.83)、(0.72±0.13) MPa、(15.47±1.63) %。 相似文献
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Mahmud I Rahman Z Keka SI Devnath S Masum N Masum N Hossain S 《Journal of oleo science》2011,60(2):79-85
The serum phosphorus level is recently considered as one of the foretelling markers for the severity of cardiovascular diseases (CVD). We therefore investigated whether the serum phosphorus level in the diabetic patients against healthy individuals could act as a possible marker for identification of vulnerability to cardiovascular disease. One hundred and thirty two human subjects were involved in the study among which one hundred and four subjects are CVD patients and twenty eight were healthy individuals. The levels of the lipid profile and the glycemic status were significantly increased in the patients than those of the control subjects (Fasting glucose, FS=8.3 ± 0.3 vs. 6.1 ± 0.0 mmol/L; blood glucose 2 h after breakfast (STAB)=12.0 ± 0.5 vs. 8.5 ± 0.7, mmol/L; HbA1c (%),6.7 ± 0.2 vs. 5.4 ± 0.3; and Total cholesterol (TC)=189 ± 4.0 vs. 162 ± 7.0; low density lipoprotein cholesterol (LDL-C), 111 ± 3.8 vs. 96 ± 5.0; triacyglycerol (TG), 202 ± 9.0 vs. 118 ± 5.3 mg/dL, respectively. The serum phosphorus level was significantly increased in CVD patients (mg/dL, patient vs. control, 5.1 ± 0.10 vs. 3.7 ± 0.1). Simple regression analyses revealed a highly significant positive correlation between serum phosphorus and TC, TG and FG. Thus the results demonstrate that the serum phosphorus level might be another parameter which is closely associated with diabetes and could also be used as a possible marker for the risk of CVD. 相似文献
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da Silva JB Temponi Vdos S Fernandes FV de Assis Dias Alves G de Matos DM Gasparetto CM Ribeiro A de Pinho Jde J Alves MS de Sousa OV 《International journal of molecular sciences》2011,12(12):8993-9008
The present study was aimed at evaluating the antinociceptive and anti-inflammatory effects of the ethanol extract from Vernonia condensata leaves in animal models, in order to afford a better understanding of these properties. The extract reduced the number of abdominal contortions at doses of 100 (51.00 ± 3.00), 200 (42.00 ± 2.98) and 400 mg/kg (39.00 ± 4.00). In formalin tests, a significant reduction in the licking time (p < 0.01) was observed in the first phase by 25.14 (200 mg/kg = 51.50 ± 4.44) and 31.15% (400 mg/kg = 48.00 ± 4.37). The doses of 100 (43.37 ± 5.15), 200 (34.62 ± 4.16) and 400 mg/kg (28.37 ± 3.98) inhibited (p < 0.001) the second phase. After 60 and 90 min of treatment, a dose of 400 mg/kg (10.13 ± 0.39 and 11.14 ± 1.33, respectively) increased the latency time. Doses of 200 and 400 mg/kg potentiated the sleeping time induced by diazepam, pentobarbital and meprobamate. The extracts (100, 200 and 400 mg/kg) showed anti-inflammatory effects by a decrease in paw edema. The extracts also reduced the exudate volume at the doses of 200 and 400 mg/kg. The leukocyte migration had significant effect (p < 0.001) at doses of 100, 200 and 400 mg/kg. The completion of additional experiments in the investigation of the antinociceptive and anti-inflammatory activities of V. condensata allowed a better understanding of the central and peripheral mechanisms involved. 相似文献