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目的探讨偏振数码照相结合计算机辅助图像分析法评价邻面去釉后釉质脱矿程度的准确性。方法于2010年3月选取青岛大学医学院附属医院口腔外科门诊因正畸需要拔除的上颌第一前磨牙40颗,沿牙冠颊舌向磨切得到80个标本,随机分为A（空白对照,未进行任何去釉处理）、B（邻面去釉）、C（邻面去釉后使用氟化泡沫）、D（邻面去釉后使用护牙素）4组。体外pH循环60d后,用偏振数码照相结合计算机辅助图像分析法定量测量各组标本邻面去釉及再矿化后的灰度值,以此来评价其釉质脱矿程度。同时用显微硬度仪定量测量各组标本的硬度值作为对照。结果（1）灰度值：A组灰度值最低,B组灰度值最高,C组和D组经过再矿化处理后灰度值较B组降低,差异有统计学意义（P〈0．05）。c组和A、D组之间灰度值差异无统计学意义（P〉0．05）。（2）硬度值：A组硬度值最高,B组硬度值最低,c组和D组经过再矿化处理后硬度值升高,但均较A组低。B组硬度值和其他3组之间比较,差异均有统计学意义（P〈0．05）,而A组与c组、c组与D组之间硬度值比较,差异均无统计学意义（P〉0．05）。结论偏振数码照相结合计算机辅助图像分析法得出的结果与显微硬度仪的定量检测结果相符合,表明了其是一种有效的定量评价釉质脱矿及再矿化效果的方法,值得临床推广。     

NiTi根管器械表面耐磨镀层的制备和性能研究

目的：研究镍钛合金表面耐磨镀层的制备工艺和性能,提高镍钛根管器械的表面硬度和耐磨性。方法：采用直流电镀法在NiTi合金表面制备了Ni—W合金镀层,通过能谱分析和X射线衍射技术（XRD）研究电镀工艺对Ni—W耐磨镀层成分和结构的影响。采用销一盘式摩擦试验机对耐磨Ni—W合金镀层的耐磨性进行测试,通过磨损失重和磨痕形貌观察评价和分析了Ni—W合金镀层的耐磨性和耐磨机理。结果：在NiTi合金表面所制备的Ni—W合金耐磨镀层的W含量在15．2．20．2wt％范围内,且镀层致密,无微观裂纹。Ni—W合金镀层的结构是W在Ni中的固溶体。与Ni—Ti合金基体相比,镀有Ni—W合金镀层的Ni—B合金试样的磨损失重大幅度降低,耐磨性显著提高;Ni—W合金镀层的硬度和耐磨性随镀层中W含量的增加而增大。结论：直流电镀技术对镍钛合金根管器械进行表面改性可显著提高其耐磨忡．     

不同年龄圆锥角膜患者的角膜硬度参数特征分析

目的：观察角膜硬度参数(SP-A1)在不同年龄以及不同严重程度分级圆锥角膜患者中的特征。

方法：横断面研究。连续纳入2018-09/2020-12在河南省立眼科医院诊断为圆锥角膜的患者247例345眼,平均年龄24.51±6.38岁。根据年龄将患者分为≤20岁组、21～30岁组和≥31岁组。采用Amsler-Krumeich(AK)分级将圆锥角膜严重程度分为AK1、AK2、AK3和AK4。测量患者视力、角膜平坦曲率(K1)、角膜陡峭曲率(K2)、角膜平均曲率(Km)、最薄点角膜厚度(TCT)。应用角膜生物力学分析仪(Corvis ST)测量患者的角膜SP-A1以及眼压、最大形变振幅(DA Max)、第1次压平时间(A1T)、第1次压平速度(A1V)、第2次压平时间(A2T)、第2次压平速度(A2V)、凹面半径(Radius)、生物力学校正眼压(bIOP)。采用Spearman秩相关分析SP-A1与其他参数的相关性。采用单因素方差分析比较不同年龄组以及不同疾病严重程度间SP-A1差异。

结果：不同年龄组间性别构成比、最佳矫正视力(LogMAR)、眼压、K1、K2、Km、TCT和严重程度分级比较差异无统计学差异(P>0.05)。圆锥角膜患者SP-A1与年龄呈弱的正相关(r_s=0.137, P=0.011)。≥31岁组患者角膜SP-A1显著高于≤20岁组和21～30岁组(P<0.05)。≤20岁和21～30岁组中SP-A1与K1、K2和Km呈负相关,≥31岁组中SP-A1仅与K2呈负相关(P<0.05)。此外,总人群及各年龄组中SP-A1与DA Max、A1V和A2T呈负相关(P<0.05),与TCT、眼压、bIOP、A1T、A2V和Radius呈正相关(P<0.05)。随着疾病严重程度的增加年龄≤20岁组和21～30岁组圆锥角膜患者的SP-A1逐渐降低(P<0.05)。年龄≥31岁的圆锥角膜患者,AK1组与AK4组、AK2组与AK3组、AK2组与AK4组SP-A1的比较差异有统计学意义(P=0.008、0.035、0.001)。

结论：圆锥角膜患者SP-A1与年龄正相关,且在年龄≤30岁的患者中,SP-A1会随着疾病严重程度增加而逐渐降低。     

洛氏硬度计（C标尺）测量结果的不确定度评定

目的：对本实验室洛氏硬度计（C标尺）测量结果的不确定度作以评定。方法：按照JJG112-2003《金属洛氏硬度计（A B C D E F G H K N T标尺）检定规程》,以C标尺为例,考虑洛氏硬度试验中标准硬度块、硬度计及试样等因素对洛氏硬度计（C标尺）测量结果的不确定度进行评定,即通过分析、计算洛氏硬度试验中产生不确定度的若干分量,计算出扩展不确定度。结果：洛氏硬度计测量结果的扩展不确定度对32.5 HRC标准硬度块为：y_1=y_1±U_（95）=33.11HRC±1.078HRC,k=2;对62.3 HRC标准硬度块为：y_2=y_2±U_（95）=63.31HRC±0.710HRC,k=2。结论：在洛氏硬度计检定过程中,测量结果的不确定度主要取决于洛氏硬度计的允许误差。评定结果令人满意,符合洛氏硬度（C标尺）的测量要求。     

软坚散结法治疗甲状腺结节有效性 和安全性Meta分析

目的:系统评价具有软坚散结功效的中药复方治疗甲状腺结节的疗效和安全性。方法:检索具有软坚散结功效的中药复方治疗甲状腺结节的RCTs,进行方法学质量评价并提取数据,用Revman5.3软件进行Meta分析。结果:纳入34篇临床随机对照试验。分析结果显示中药+西药组vs西药组、中药组vs西药组,在总有效率、甲状腺结节直径缩小方面差异有统计学意义。结论:中药治疗甲状腺结节疗效优于西药治疗,且不良反应少,相对安全。     

Effect of Vacuum Heat Treatment on the Element Diffusion Behavior and Corrosion Resistance of Al2O3-3wt.%TiO2 Coating of Q235 Steel

In this study, we address the effect of vacuum heat treatment on the morphology of Al₂O₃-3wt.%TiO₂ coating, element diffusion behavior, coating hardness, and corrosion resistance. The pores, cracks, and non-liquefied particles on the as-heat treated coating surface of the vacuum-heat-treated coating were observed and compared with the as-sprayed coating using a scanning electron microscope. The diffusion behavior of the elements in the coating was demonstrated by using a line scanning of a cross-section of the coating. Hardness and corrosion-resistance test results were used to judge the effect of a vacuum heat treatment on the coating. The research results show that compared with atmospheric heat treatment, the vacuum heat treatment had less effect on the pores, cracks, and non-liquefied particles on the surface of the coating. However, in the absence of new oxide formation, the pores and cracks in the cross-section of the coating were significantly improved by the vacuum heat treatment. The surface hardness and corrosion resistance of the coating were significantly improved. The crack defects were eliminated, and the uniformity of TiO₂ distribution was improved, which are the main factors that improved the coating performance after vacuum heat treatment. The combination of the coating and the substrate is strengthened, and an Al₂O₃ and TiO₂ interdiffusion zone is formed when the coating undergoes vacuum heat treatment, which is the main mechanism improving the performance of the AT3 coating.     

High-Performance Thermal Interface Materials with Magnetic Aligned Carbon Fibers

Thermal interface materials with high thermal conductivity and low hardness are crucial to the heat dissipation of high-power electronics. In this study, a high magnetic field was used to align the milled carbon fibers (CFs, 150 μm) in silicone rubber matrix to fabricate thermal interface materials with an ordered and discontinuous structure. The relationship among the magnetic field density, the alignment degree of CFs, and the properties of the resulting composites was explored by experimental study and theoretical analysis. The results showed higher alignment degree and enhanced thermal conductivity of composites under increased magnetic flux density within a certain curing time. When the magnetic flux density increased to 9 T, the CFs showed perfect alignment and the composite showed a high thermal conductivity of 11.76 W/(m·K) with only 20 vol% CF loading, owing to the ordered structure. Meanwhile, due to the low filler loading and discontinuous structure, a low hardness of 60~70 (shore 00) was also realized. Their thermal management performance was further confirmed in a test system, revealing promising applications for magnetic aligned CF–rubber composites in thermal interface materials.     

The Influence of Low-Molecular-Weight Monomers (TEGDMA,HDDMA, HEMA) on the Properties of Selected Matrices and Composites Based on Bis-GMA and UDMA

Bisphenol A-glycidyl methacrylate (bis-GMA) and urethane dimethacrylate (UDMA) are usually combined with low-viscosity monomers to obtain more desirable viscosity, handling characteristics and general properties. The present study determined the flexural strength (FS), flexural modulus (FM), diametral tensile strength (DTS), and hardness (HV) of five matrices and composites based on these resins. The polymerization shrinkage stress (PSS) was also studied for the composites. The polymer matrices were formed using bis-GMA and UDMA. TEGDMA, HEMA and HDDMA acted as co-monomers. The composites had 45 wt.% of filler content. The highest FS and FM were obtained from the UDMA/bis-GMA/TEGDMA/HEMA matrix and the composite (matrix + filler). The best DTS values were obtained from the UDMA/bis-GMA/HEMA matrix and the composite. One of the lowest values of FS, FM, and DTS was obtained from the UDMA/bis-GMA/HDDMA matrix and the composite. All the composites demonstrated similar hardness values. The lowest polymerization shrinkage stress was observed for the UDMA/bis-GMA/TEGDMA/HEMA composite, and the highest PSS was observed for the UDMA/bis-GMA/TEGDMA/HDDMA composite. The addition of HEMA had a positive effect on the properties of the tested materials, which may be related to the improved mobility of the bis-GMA and UDMA monomers.