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61.
62.
This paper presents a photogrammetry-based volume measurement framework for the particle density estimation of Lightweight expanded clay aggregate (LECA). The results are compared with computed tomography (CT) and Archimedes’ method measurements. All of the steps required in order to apply the proposed approach are explained. Next, we discuss how the interpretation of open pores affects the results of volume measurements. We propose to process the shapes obtained from different methods by applying an Ambient Occlusion algorithm with the same threshold, t = 0.175. The difference between the CT and SfM methods is less than 0.006 g/cm3, proving that the photogrammetry-based approach is accurate enough. The Archimedes’ method significantly overestimates the density of the particles. Nevertheless, its accuracy is acceptable for most engineering purposes. Additionally, we evaluate the accuracy of shape reconstruction (in terms of the Hausdorff distance). For 95% of the grain’s surface, the maximum error is between 0.073 mm and 0.129 mm (depending on the grain shape). The presented approach is helpful for measuring the particle density of porous aggregates. The proposed methodology can be utilized in order to estimate intergranular porosity, which is valuable information for the calibration of DEM models.  相似文献   
63.
To enhance the formability of magnesium alloys, inhibition of basal texture development by the particle-stimulated nucleation (PSN) effect has attracted significant interest. However, its contribution to texture development is not easily observed due to the separation of texture from the conventional deformation behavior. This study aims to separate the Ca texture from the deformation behavior of AZX611 alloy and quantify it using scanning electron microscopy with electron backscatter diffraction (SEM-EBSD). Since Ca in the AZ61 magnesium alloy precipitated as Al2Ca, the hot-rolled magnesium alloys AZ31, AZ61, and AZX611 were used. High temperature compression was conducted at 723 K, the strain rate 0.05/s and 0.005/s and the true strain up to −1.0. Dynamic recrystallization was observed in each specimen and the Ca-free alloys showed dislocation glide at high strain rates and solute drag at low strain rates. When the dislocation glide dominated, basal texture was strengthened. In contrast, solute drag caused non-basal texture development. Precipitation hardening caused AZ61 to have higher flow stress than those of the Ca-free alloys by the PSN effect; its texture was observed separately because the PSN grain growth around the precipitation and orientation was specific, similar to the one developed at the solute atom drag.  相似文献   
64.
Today, Ni-Cr steel is used for advanced applications in the high-temperature and electrical industries, medical equipment, food industry, agriculture and is applied in food and beverage packaging and kitchenware, automotive or mesh. A study of input steel powder from various stages of the recycling process intended for 3D printing was conducted. In addition to the precise evaluation of the morphology, particle size and composition of the powders used for laser 3D printing, special testing and evaluation of the heat-treated powders were carried out. Heat treatment up to 950 °C in an air atmosphere revealed the properties of powders that can appear during laser sintering. The powders in the oxidizing atmosphere change the phase composition and the original FeNiCr stainless steel changes to a two-phase system of Fe3Ni and Cr2O3, as evaluated by X-ray diffraction analysis. Observation of the morphology showed the separation of the oxidic phase in the sense of a brittle shell. The inner part of the powder particle is a porous compact core. The particle size is generally reduced due to the peeling of the oxide shell. This effect can be critical to 3D printing processing, causing defects on the printed parts, as well as reducing the usability of the precursor powder and can also change the properties of the printed part.  相似文献   
65.
Conclusion: The results of the present investigation suggest that modification of HA could improve efficiency and durability in augmentation laryngoplasty. Objectives: Injection laryngoplasty (IL) is one of the most suitable options for treatment of glottic insufficiency, which is caused by vocal fold (VF) paralysis, atrophy, or scarring. Hyaluronic acid (HA) is a widely used material for VF injection. This study was intended to evaluate the durability and efficiency of HA of different particle sizes for VF augmentation. Methods: Three types of HA, Restylane®, monophasic low-viscosity, and unequal particle-sized middle-viscosity HA were injected into the left VF of three groups with eight rabbits each. Results: After 6 and 10 weeks, the injected site was evaluated endoscopically, histologically, radiologically, and functionally. None of the 24 rabbits showed any signs of respiratory distress. Computed tomography (CT) images and endoscopic evaluation revealed sufficient augmented volume of the injected VF in all treated groups 6 weeks after the injection. Histological data at week 10 showed that unequal particle-sized HA did not migrate from its original injection site, while other HAs migrated to the periphery of the arytenoid cartilage. Videokymographic analysis showed more favorable vibrations of unequal particle-sized HA injected VF mucosa 10 weeks post-injection, compared to the other treatment groups.  相似文献   
66.
67.
 目的 研究海藻酸钠改性载顺铂磁性纳米药物的组织分布特征。方法 昆明小鼠84只,随机分为实验组和对照组,分别按顺铂剂量10 mg·kg-1从尾静脉推注载顺铂磁性纳米药物或顺铂0.2 mL,于给药后1,2,4,10 h,1,3,7 d,分7个时间点各处死实验组和对照组一组小鼠(6只),取出小鼠的心、肝、脾、肺、肾组织,经强酸湿法消化后在原子吸收光谱仪上测定各组织样本中铂的浓度。结果 给药后7个不同时间点磁性顺铂在各组织中的浓度均明显高于顺铂(P<0.001),7 d后实验组中肝、脾、肾组织中磁性顺铂的浓度分别为(8.31±1.92 )、(24.23±6.02)、(3.02±0.74) μg·g-1,而对照组中顺铂分别只有(1.47±0.64)、0、(1.62±0.38) μg·g-1。结论 一次性给药后海藻酸钠改性载顺铂磁性纳米药物在小鼠体内的分布与顺铂不同,前者主要分布于肝、脾,并在组织中维持较长时间,后者主要分布于肝、肾,较快从组织中被清除。  相似文献   
68.
目的:确定透明质酸(HA)瘤内分布,为肺肿瘤的早期诊断提供依据。方法:免疫组化定位肿瘤内HA的分布,亲和层析法从仔猪肋软骨提取猪软骨链蛋白(p-CLP),125I标记p-CLP进行体内分布代谢示踪学研究。结果:HA免疫显色提示肿瘤细胞外基质HA有较高表达,放射示踪实验示1~7h内实验组单位质量的放射性计数百分比(13.46%~29.14%)明显高于对照组(6.4%~13.70%),差异有统计学意义,P<0.01。结论:p-CLP在肺肿瘤内浓集,125I标记p-CLP体内代谢示踪能够为肺肿瘤等疾病的早期诊断提供实验依据。  相似文献   
69.
目的探讨CT引导下125I粒子植入联合TACE治疗原发性肝癌合并门静脉癌栓的临床价值。方法抽取佛山南海社会福利中心康复医院放射科2010年1月~2013年10月收治的18例原发性肝癌合并门静脉癌栓患者作为研究对象,并给予6个月~2年的随访,同时结合其临床资料进行回顾性分析。结果经治疗后随访发现,18例患者中,共有14例获得有效治愈,总有效率为77.8%。结论给予原发性肝癌合并门静脉癌栓患者CT引导下125I粒子植入联合TACE治疗,能够有效保证临床治疗效果,值得推广。  相似文献   
70.
在分析基本微粒群优化算法(PSO)和支持向量机(SVM)原理的基础上,采用带有末位淘汰机制的微粒群优化算法优化支持向量机的参数,建立了延迟焦化装置粗汽油干点软测量的微粒群支持向量机模型.该方法利用支持向量机结构风险最小化原则和PSO算法快速全局优化的特点,用于软测量建模.仿真实验表明:所建模型的泛化性能较好,模型具有较高的精度.  相似文献   
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