Effect of Layered Double Hydroxides on the Deterioration Process of Cement Paste under Sulfate Attack

This study investigated the effect of layered double hydroxides (LDHs) on the deterioration process of cement paste in the sulfate environment. Cement pastes with the addition of original and calcined LDHs at 2.5 wt.% and 5.0 wt.% of cement were exposed to Na₂SO₄ solution for 360 days. The macroscopic performance of the cement paste was assessed based on mass variation, porosity, compressive strength, and content of sulfate ions. Furthermore, the microhardness, microstructures, and composition of the degraded pastes were examined using Vickers hardness (HV), mercury intrusion porosimetry (MIP), scanning electron microscope (SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The results indicate that cement paste incorporated with LDHs can mitigate the corrosion caused by sulfate effectively, especially in the case of calcined LDHs (C-LDHs), which primarily increase the adsorption of sulfate. Compared with the control specimen, the 180 d compressive strength loss ratio of specimens with 2.5 wt.% and 5.0 wt.% of C-LDHs decreased by 63.66% and 80.51%, respectively. Moreover, LDHs can reduce the amount of ettringite crystals, densify the microstructure, and refine the pore structure to mitigate the cement paste’s sulfate corrosion significantly. Compared with the control specimen, the 180 d harmful pore volume fraction of specimens laced with 2.5 wt.% and 5.0 wt.% C-LDHs decreased by 43.77% and 54.51%, respectively. In terms of the content of C-LDHs, an optimal content of C-LDHs could ensure the dominant effect of adsorption, while excessive C-LDHs could refine pores. In addition, Vickers hardness has an excellent correlation with compressive strength, which could precisely predict the compressive strength. Moreover, by combining the Vickers hardness distribution and content distribution of sulfate ions, the cross-section of the paste could be classified into four regions to evaluate the deterioration process accurately: the degraded zone, the strengthened zone, the invaded zone, and the intact zone.     

实时超声弹性成像在甲状腺乳头状癌诊断中的应用价值

目的 探讨甲状腺乳头状癌采用实时超声弹性成像技术的应用价值。方法 回顾性分析2013年9月~2014年9月入我院进行手术治疗的甲状腺乳头状癌患者、甲状腺良性结节患者各30例,所有患者术前行甲状腺超声诊断技术检查,术后经病理组织标本活检证实为甲状腺乳头状癌、甲状腺良性结节。对两组病理诊断结果、超声图像特点和实时超声弹性成像结果进行对比和分析。结果 甲状腺乳头状癌结节内的钙化多数为微小钙化,结节边缘毛糙,结节纵横比≥1,差异具有统计学意义（P < 0.05）。乳头状癌组的结节为Ⅳ级的个数明显多于良性结节组,乳头状癌组的结节为Ⅳ级的个数明显多于良性结节组,差异均具有统计学意义（P < 0.05）。结论 实时超声弹性成像能够准确的评价甲状腺结节的相对硬度,对鉴别甲状腺良、恶性肿瘤及甲状腺乳头状癌具有重要的应用价值。     

A Study on the Acquirement Method of Mechanical Property Parameters in the Different Base Materials Composite Region of Clad Rebar

Clad rebar is one of the key structures of marine and construction services. Therefore, it is of great importance to acknowledge the mechanical property parameters of the composite region in the structural integrity evaluation of clad rebar. The different base materials of clad rebar (20MnSiV/316L steel, 35#/316L steel, 45#/316L steel, and 55#/316L steel) are researched in this study. The composite area is further refined, and simultaneously, a refinement model of the composite region of clad rebar is established. In view of the fact that a surface hardness experiment is quite easy to conduct, a proposed method consists of obtaining the mechanical property parameters of materials using the surface hardness test. The mechanical property parameters are acquired; moreover, the relationship between yield stress and surface hardness of the stainless steel clad rebar is set up. We used this method to acquire the mechanical parameters of a composite surface uneven area of clad rebar, and we established a mechanical parameters mathematics model of clad rebar, it is a significant basis for a structural integrity evaluation of cladding materials.     

Structural,Physical, and Mechanical Analysis of ZnO and TiO2 Nanoparticle-Reinforced Self-Adhesive Coating Restorative Material

This study aimed to modify an EQUIA coat (EC; GC, Japan) by incorporating 1 and 2 wt.% of zinc oxide (ZnO; EC-Z1 and EC-Z2) and titanium dioxide (TiO₂; EC-T1 and EC-T2) nanoparticles, whereby structural and phase analyses were assessed using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), respectively. Thermogravimetric analysis/differential scanning calorimetry, micro-hardness, and water absorption analyses were conducted, and the microstructure was studied by scanning electron microscopy/energy-dispersive spectroscopy. FTIR spectra showed a reduction in peak heights of amide (1521 cm⁻¹) and carbonyl (1716 cm⁻¹) groups. XRD showed peaks of ZnO (2θ ~ 31.3°, 34.0°, 35.8°, 47.1°, 56.2°, 62.5°, 67.6°, and 68.7°) and TiO₂ (2θ ~ 25.3°, 37.8°, 47.9, 54.5°, 62.8°, 69.5°, and 75.1°) corresponding to a hexagonal phase with a wurtzite structure and an anatase phase, respectively. Thermal stability was improved in newly modified materials in comparison to the control group. The sequence of obtained glass transitions was EC-T2 (111 °C), EC-T1 (102 °C), EC-Z2 (98 °C), EC-Z1 (92 °C), and EC-C (90 °C). EC-T2 and EC-T1 showed the highest (43.76 ± 2.78) and lowest (29.58 ± 3.2) micro-hardness values. EC showed the maximum water absorption (1.6%) at day 7 followed by EC-T1 (0.82%) and EC-Z1 (0.61%). These results suggest that EC with ZnO and TiO₂ nanoparticles has the potential to be used clinically as a coating material.     

剪切波弹性成像测量宫颈硬度的可重复性研究

目的：评价剪切波弹性成像（shear wave elastography,SWE）测量育龄期健康未育女性宫颈杨氏模量值的可重复性。方法：由同一名接受过SWE检测培训的高年资医师于同一天不同时间点,前后2次对100名处于育龄期但未育的健康女性宫颈行剪切波弹性成像,测量时选取宫颈4个位点：内口前唇（anterior lip of the inner mouth,IA）、内口后唇（posterior lip of the inner mouth,IP）、外口前唇（anterior lip of the outer mouth,EA）及外口后唇（posterior lip of the outer mouth,EP）,获取育龄期健康未育女性宫颈杨氏模量值。使用组内相关系数（interclass correlation coefficient,ICC）评价检查者内可重复性,同时绘制BlandAltman散点图评价测量一致性。结果：宫颈4个测量位点的前后2次测值均无统计学差异（P>0.05）;宫颈IA、EA、EP处杨氏模量值的组内相关系数分别为0.828、0.785、0.768,提示组内可重...     

An in vivo method for microhardness measurements on human teeth

A non-destructive, in vivo method of measuring the enamel hardness directly on patients is described. Normal values on 39 students arc given and compared with those of five patients, one of whom suffered from abnormal oral acid concentration, and the others from the effects of various degrees of hyposialosis caused by radiologic treatment of tumors in head and neck. The difference between the two groups was significant below the 0.1% level. It was suggested that the method may be used to test the degree of salivary gland inactivation after radiologic treatment and the efficiency of different saliva substitutes used to alleviate the effects of hyposialosis.     

Hardness evaluation of penile prostheses

AIM: This work investigates the hardness and buckling force of penile prostheses to further understand the rigidity of penile prostheses before and after implantation. METHODS: Evaluated herein are four prosthetic samples (three inflatable, one semi-rigid), five real prostheses (one inflatable, four semi-rigid), and one prosthesis after implantation. The hardness is measured with a Shore Durimeter by pressing the tester's indentor to the surface of the specimen. A volunteer with inflatable prosthesis implantation is evaluated with respect to penile hardness versus various numbers of pumping. The buckling force of the prosthesis is also determined by a push-pull gauge and a specially designed sampling table. RESULTS: Results in this study demonstrate that although the inflatable prosthesis could only be pumped to a certain amount of hardness, hardness and buckling force correlate well with each other. After reaching the hardness limit, prostheses can even be pumped a further few times. However, continuous pumping only puts more tension on the prosthetic material without increasing hardness and could induce mechanical failure of the prosthesis. Results also indicate that the buckling force decreases with increasing length of the semirigid prostheses, and increases when the prosthesis has a larger diameter. CONCLUSION: This mechanical measurement of rigidity in penile prostheses could provide more information to clinicians about the penile prosthesis before surgical implantation, and to patients about prosthesis usage after implantation.     

苏锡常地区建制镇水厂出厂水中总硬度及微量元素调查

调查了苏锡常地区建制镇水厂出厂水中的总硬度及微量元素的含量。结果表明：该地区以地下水为水源的水厂水中总硬度、铁、锰的含量较高，超标严重。两种水源中锌的含量均不高，所有水厂出厂水中硒、铜、铬、砷、铅、汞均未检出。     

Response of juvenile centrarchids to sublethal concentrations of waterborne selenium. I. Uptake,tissue distribution,and retention

Juvenile bluegill (Lepomis macrochirus and largemouth bass (Micropterus salmoides) contained significantly elevated levels of selenium in all tissues examined after exposure to 10 μ/l for 120 days. The relative accumulation of selenium in specific tissues was: spleen > heart > liver > kidney > erythrocytes > gill > plasma > white muscle > gonad > intestine > stomach > brain. Water temperature and hardness did not affect the equilibrium concentrations or tissue distribution observed after 90 days, although earlier values were influenced. Selenium concentrations remained unchanged after 30-day elimination trials in spleen, liver, kidney, and white muscle, but exhibited a half-life retention time ≤ 15 days in gill and erythrocytes. The largest difference between species was in the selenium content of white muscle, with bluegill concentrating approximately twice that of largemouth bass. The major uptake pathway appears to be crythrocyte transport mediated by active oxo-groups on the selenium anion, with subsequent exchange at preferential sites. High apportionment into the spleen and heart may be influenced by differential formation of selenoproteins. Even though no mortality resulted under these controlled experimental conditions, possible pathologic enhancement, combined with the added body burden from dietary intake, strongly suggest the potential for toxicity in natural systems where waterborne selenium concentrations approach 10 μ/l.     

陈香路百路片压片工艺研究

本文以陈香路百路片为例，试验了压片工艺所施压力、颗粒及成品的含水量对中草药片剂硬度、崩解时限和脆碎度的影响，以优选压片工艺，消除松片、掉粉的质量问题。