Masking severely tetracycline-stained teeth with ceramic laminate veneers

When the primary restorative objective is the reinstatement of vital natural tooth color, dark tetracycline-stained teeth still represent the ultimate challenge for ceramic laminate veneers. Masking severe stain with opaquing composite resins is a significant advancement; however, the procedure requires additional chairtime, is technique sensitive (to avoid excessive opacity), and involves removal of additional tooth structure. The learning objective of this article is to describe and compare two different methods for masking tetracycline-stained teeth. The article illustrates the natural tooth color derived from ceramic laminate veneers when bonded to opaque composite resins in the maxillary arch, and compares it to a new ceramic veneer formulation in the mandibular arch, which masks the stain, eliminates the need for subopaquing with composite resins, and resembles the qualities of natural tooth color.     

高耐磨陶瓷衬板在高炉料车上的应用

高炉料车衬板磨损问题，是炼铁厂普遍存在的难题，它不仅影响炼铁系统的正常运行，而且增加日常维护的工作量。高耐磨陶瓷衬板的应用，成功地解决了料车磨损问题。     

Reconstruction of composite facial defects: the combined application of multiple reconstructive modalities

OBJECTIVE: To describe the combined use of craniofacial skeletal reconstruction, tissue expansion and microvascular free tissue transfer in the repair of major composite facial defects. DESIGN: Case series with an integrated team approach. SETTING: Craniofacial unit, university teaching hospital. PATIENTS: Three cases were selected to best illustrate the combined use of the three modalities in reconstruction of acute traumatic, congenital and post-traumatic facial defects. A 15-year-old boy had a shotgun wound to the face; a 23-year-old man had Treacher Collins syndrome; and a 55-year-old woman had a post-traumatic composite defect of the central midface. INTERVENTIONS: Preoperatively, complete neurologic, ophthalmologic and dental examinations, anthropometric analysis, prosthodontic assessment, computed tomography and computer graphics. Operatively, craniofacial exposure followed established surgical principles. Skeletal reconstruction was performed to provide accurate positioning of bony segments and three-dimensional stability. Bone grafting was used when necessary to restore bony continuity and increase stability. Tissue expansion was used to provide more locally available tissue for wound closure and resurfacing composite defects. Microsurgical free tissue transfer was used to provide functional replacement of deficient tissues. RESULTS: The results of the modalities used for reconstruction of these composite facial defects are illustrated for each case described. CONCLUSIONS: The use of multiple modalities, including craniofacial skeletal reconstruction, tissue expansion and free tissue transfer, allow the surgeon to address the specific functional and anatomical requirements associated with composite facial defects that are characterized by a combined deficiency of multiple tissues in the craniofacial region.     

耐火纤维喷涂结合剂的研究与应用

针对通常耐火纤维喷涂中存在的问题，分析耐火纤维喷涂用结合剂的性能要求和常用结合剂的结合机理，完成了不同使用温度条件下耐火纤维喷涂用结合剂的实验研究。通过实际应用，取得了优良的使用效果。     

Endoscopic application in aesthetic and reconstructive facial bone surgery

Twenty-three cases of endoscopically assisted facial bone surgery were performed over the past 3 years. Our series is consistent with 16 cases of aesthetic contouring surgery and 12 treatments of facial bone fracture, including three cases for recontouring of frontal bone, three cases for recontouring of zygoma, endoscopically assisted correction of three zygomatic and blowout fractures, four cases for rhinoplasty and septoplasty for deviated nose, and three cases for mandible contouring surgery. To accomplish this technique, a rigid 4-mm, 30-degree down-angled endoscope was used. The frontal bone or zygomatic arch was approached endoscopically through two or three small incisions on the frontal or temporoparietal scalp. All endoscopic instruments were then manipulated through these incisions. The approach for endoscopically assisted rhinoplasty is the same as with standard rhinoplasty procedures. The approach for zygoma complex and maxillary sinus needs an intraoral incision. Recontouring of zygoma, mandible, and nasal dorsum by an air-driven burr and rasp was performed with endoscopic visual assistance. A plate and screw fixation for zygomatic arch fracture requires an additional small skin incision over the plate for the trocar method. The duration of follow-up ranged from 6 months to 30 months. The postoperative course was satisfactory with a few complications. The extra time needed for the endoscopic procedures was less than 1 hour. Endoscopically assisted facial bone surgery can be performed with adequate visualization and direct manipulation of all facial bones. Complications usually associated with extensive incisions in the bicoronal approach may be avoided. Poor visualization in the conventional approach for operation of orbit, nose, maxillae, and mandible may be avoided by use of the endoscope. This technique may prove to be ideal for aesthetic surgery for facial skeleton with smaller scar and less morbidity.     

整体式陶瓷杯炉缸内衬的设计实践和应用效果

针对炉缸内衬破损的主要因素,将炼铁工艺设计和高炉长寿实践成果融入炉缸内衬设计,对炉缸内衬进行包含炼铁工艺设计、内衬性能设计、砌体结构设计等方面的体系设计为长寿型现代大型高炉奠定寿命技术基础至关重要.已经应用于多座大型高炉的整体式陶瓷杯炉缸内衬通过体系性设计,获得持续稳定、密闭等有益于长寿的技术特征,它们的实际使用情况表明,炉缸内衬温度结果符合设计预期,陶瓷杯侵蚀速率缓慢,理论推测可在10年以上的冶炼周期中为炭砖提供有效保护.     

Electrochemical diagnostics of the combatibility of stomatological metal materials after thermal treatment for the application of ceramic coatings

The electrochemical properties of stomatological metallic materials are investigated after their high-temperature annealing (at 900–1200°C) in air during exposure in a biological solution (imitating the human saliva). The materials were maintained in the steady state and under conditions of renovation of a thermally oxidized surface. It is shown that the electrode potentials change nonmonotonically, which proves the presence of a porous thermal oxide film on the surface of metals. The highest rate of healing of pores during exposure of samples in solution is observed for NiCrMo, VT5, VT14, and CoCrMo alloys. Based on the results of measuring the emf of the galvanic currents in the Ti (VT1-0)-metal (alloy) paris, as well as of the pulse currents at the moment of renovation of the surface of one element of the contact pair, a conclusion is drawn on the possibility of applying all materials studied in the pair with the control material (nonannealed titanium), and the most preferable combinations are determined.     

FR-S500型变频器在陶瓷过滤机的应用及故障分析与对策

介绍FR-S500型变频器在陶瓷过滤机上的应用,谈论变频器技术特性和优点。通过在陶瓷过滤机上的应用,分析了变频器的常见故障原因及相应的对策。     

冶金烟气微孔陶瓷管膜研制及深度除尘应用的研究

提出了将SiC、Al2O3等原料等静压成型后烧制成多孔陶瓷基体,再通过多次浸浆、干燥达到所需膜厚度后,采用热喷涂制成非对称陶瓷复合膜管的新工艺技术.研发出能够处理高温烟气的微孔陶瓷管复合膜除尘器,应用到冶金高温烟气中进行深度除尘和净化.采用了SEM、EDS等手段对多孔陶瓷基体和微孔复合膜进行表征,结果表明其具有良好的微孔结构和物理性质.自行设计了一套测定过滤效率的冷态试验装置模型,并通过实验确定了合理的参数.     

高效能陶瓷燃烧器在萍钢350 m3高炉上的应用

对高效能陶瓷燃烧器在萍钢350m^3高炉上的使用情况进行了总结。在纯烧高炉煤气的条件下,萍钢高炉热风温度可达到1100℃,为实现高炉高产、低耗、高效创造了条件。     

基于改进MMI的HMM训练算法及其在面部表情识别中的应用

提出一种改进的最大互信息(MMI)准则函数并把它应用于隐马尔可夫模型(HMM)的参数估计,重新推导了HMM的迭代公式.该准则函数相对于原来准则函数定义更为合理,能有效利用训练样本集中的鉴别信息,使得训练数据得到充分利用,提高了HMM的性能.把这种改进的HMM算法应用于面部表情识别,利用改进的光流算法提取面部表情特征向量序列,并利用改进HMM算法和BP神经网络构建了面部表情混合分类器.实验结果表明了该方法能有效提高面部表情识别率,有效解决HMM参数估计问题.