A new wavelet based fault detection,classification and location in transmission lines

This paper deals with the application of wavelet transforms for the detection, classification and location of faults on transmission lines. A Global Positioning System clock is used to synchronize sampling of voltage and current signals at both the ends of the transmission line. The detail coefficients of current signals of both the ends are utilized to calculate fault indices. These fault indices are compared with threshold values to detect and classify the faults. Artificial Neural Networks are employed to locate the fault, which make use of approximate decompositions of the voltages and currents of local end. The proposed algorithm is tested successfully for different locations and types of faults.     

Investigations of TaB2 on oxidation-inhibition property and mechanism of Si-based coatings in aerobic environment with broad temperature region for carbon materials

To investigate the formation mechanism of the dendrites glass-ceramics and the effect of TaB₂ modifier on the oxidation-inhibition ability of Si-based coatings in aerobic environment with broad temperature region for carbon materials, the Si-based coatings modified with different TaB₂ content were fabricated by the liquid phase sintering method. The fabricated coatings and its corresponding composite powders were investigated in dynamic TG aerobic environments up to 1500 ℃. The initial oxidation temperatures of Si-based coatings modified with TaB₂ powders are almost completely suppressed to 800 ℃. With the increase of TaB₂ phase content, the relative oxygen permeability of the Si-based coatings is significantly reduced, which can be interpreted as the generation of liquid boride, silicide and Ta-Si-B-O compound glass ceramics those can improve the stability of the coating. The formation mechanism of the dendrites glass-ceramics was illustrated.     

Damage of the ocular surface from indoor suntanning—Insights from in vivo confocal microscopy

PurposeTo evaluate the ocular surface at the microstructural level of adults who habitually undertake indoor-suntanning utilising in vivo confocal microscopy.MethodsParticipants were prospectively recruited and enrolled into either а study group (n = 75) with a history UV indoor tanning, or a control group (n = 75) with no prior history of artificial tanning. The study group participated in voluntary tanning sessions performed with standard equipment and maintained their usual routine for eye protection. Slit lamp biomicroscopy and in vivo confocal microscopy were performed at baseline before undertaking a series of suntanning sessions (10 sessions of 10 min duration over a 15 day period), within three days after the last session, and four weeks after the last session. Control group participants were examined at baseline and 8 weeks later and did not participate in tanning sessions.ResultsAll participants were female with a mean age of 25 ± 4 years and 24 ± 4 years in the study and control groups, respectively. No clinically significant changes were observed in either group over time using slit lamp biomicroscopy (all p ≥ 0.05), however, statistically significant differences were observed between the study and the control group for all corneal layers imaged using confocal microscopy (all p ≤ 0.03). Characteristic cystic conjunctival lesions with dark centres and bright borders were observed in 95% of the study group before and in 100% after the suntanning sessions.ConclusionIndoor suntanning resulted in statistically significant microstructural changes in the cornea and the bulbar conjunctiva that are undetectable with slit lamp biomicroscopy.     

基于新标准的俄罗斯釆金业职业风险评估

当前俄罗斯正在进行立法改革以实现治理体系现代化，其中改革的重点是国家管理体系中的劳动保护、工业安全和突发事件的应急处理。过去的立法体系侧重于对受伤员工提供健康补偿和医疗救护，而新的立法体系则以预防为主，以期通过建立完善的风险管理机制和运行规则，提高安全生产水平、普及安全文化教育，保障员工的生命安全。新标准强调企业必须进行职业风险评估，并将职业风险评估纳入企业工作管理体系。论文以采金业为例，选取伊尔库茨克州波戴波区金矿露天采场为研究案例，探讨了现代化职业风险评估的方法，明确了职业风险评估首先要进行危害鉴别，编制了风险源管理档案清单。采用实测员工风险因素的“记分法”和数学模拟“矩阵法”完成了伊尔库茨克州波戴波区金矿露天采场主要职业的风险评估。研究表明: 在钻井爆破作业场所，由碎石的喷射、粉尘的排放和噪声效应引起的危险为不可接受风险，通过实施安全生产制度（即遵守安全标准和技术要求、为工人提供防护装备）,可将高风险和不可接受风险化解为可接受风险；阐述了高风险职业，编制了风险手册，提出了改善工作条件的首要措施是消除影响爆破手和钻机操作员的有害因素，并为员工提供能更有效预防噪音和振动的个人防护用品。     

面向云计算应用层演化的隐私保护方法研究

云计算应用层中的组合服务具有演化属性,因此,隐私数据在服务组合过程中,用户的隐私数据可能会因为服务或服务流程的演化而暴露。根据服务演化的特征,以描述逻辑为基础,提出了一种面向云计算应用层演化的隐私保护方法。对隐私协议进行形式化描述;根据服务的演化特征,对服务的演化进行监控,保证满足用户的隐私需求;利用实例研究证明该方法的正确性与可行性。     

面向连续查询的敏感语义位置隐私保护方案

针对连续查询位置服务中构造匿名区域未考虑语义位置信息导致敏感隐私泄露问题，通过设计[(K,θ)]-隐私模型，提出一种路网环境下面向连续查询的敏感语义位置隐私保护方案。该方案利用Voronoi图将城市路网预先划分为独立的Voronoi单元，依据用户的移动路径和移动速度，选择具有相似特性的其他[K-1]个用户，构建匿名用户集；利用匿名用户集用户设定的敏感语义位置类型和语义安全阈值，以及用户所处语义位置的Voronoi单元，构建满足[(K,θ)]-隐私模型的语义安全匿名区域，可以同时防止连续查询追踪攻击和语义推断攻击。实验结果表明，与SCPA算法相比，该方案在隐私保护程度上提升约15%，系统开销上降低约20%。     

增强现实中基于位置安全性的LBS位置隐私保护方法

为了解决基于位置的服务(LBS)和增强现实(AR)技术快速发展带来的用户位置隐私泄露的隐患,分析了现有的位置隐私保护方法的优缺点,提出基于位置安全性的位置隐私保护方法。将区域安全度和伪装区域引入该方法中,将提示某区域是否需要保护这一度量标准定义为区域安全度,非安全区域(即需要给予保护的区域)的区域安全度设置为1,安全区域(即不需要保护的区域)设置为0,通过扩大区域安全度和识别等级来计算位置安全度。实验结果表明,该方法与未引入位置安全性的方法相比降低了平均定位误差,提高了平均安全性,从而有效地保护了用户的位置隐私,提高了LBS的服务质量。     

域名管理体系与注册保护初探

域名具有重要的品牌价值,研究域名管理体系有利于开展域名注册与保护。现行域名注册规则容易导致域名与字号、商标、姓名等传统权利的冲突。互联网域种类繁多、层级结构复杂,企业应当建立域名注册评估机制、抢注侵权监测机制,加强域名注册与维权保护。     

关于高炉炉缸长寿的关键问题解析

 高炉长寿化是大型高炉发展的必然趋势,实现高炉长寿的关键在于弄清高炉侵蚀的根本原因。从高炉炉缸侵蚀机理、高炉炉缸象脚型侵蚀原因、高炉炉缸圆周方向侵蚀不均匀性、高炉冷却强度与冷却效率以及高炉炉缸维护技术等5个方面探讨了高炉长寿存在的共性问题,指出高炉炉缸炭砖损毁的本质是碳不饱和铁水对炭砖的溶蚀。具体结果表明,首先,高炉炉缸象脚型侵蚀最严重部位位于高炉炉缸死料柱的根部位置;其次,阐明了直接导致高炉存在不均匀侵蚀的主要原因在于冷却系统的冷却水量和送风系统的风量在高炉周向方向分配不均匀;然后,阐明了冷却系统的作用本质是降低耐火材料热面温度,并提出了高炉冷却强度指数及高炉冷却效率指数;最后,分析了采用无钛矿护炉和钛矿护炉两种模式的高炉炉缸维护技术。     

碱铝硅酸盐玻璃化学强化关键影响因素概述

化学强化是一种玻璃机械强度增强方法,适用于异型、超薄、高碱、高膨胀玻璃增强,因新型超薄显示产品的屏幕保护玻璃发展需要,化学强化技术重新在碱铝硅酸盐玻璃品种掀起研究热潮。本文对化学强化本质及铝硅酸盐玻璃在屏幕保护玻璃应用进行了回顾,基于玻璃化学强化的高CS、DOL和低CT诉求,归纳总结了关键影响因素,第1,碱铝硅酸盐玻璃的成分及结构是基础,氧化铝有利玻璃网络孔隙增大创造交换通道,氧化钠或氧化锂是离子交换关键物质;第2,对于玻璃组成和结构设计,要求玻璃网络键合度R=O/Si或O/(Si+Al)满足2.15~2.40,碱金属氧化物质量分数大于13%且膨胀系数大于6×10^-6/℃;第3,在化学强化工艺方面,化学强化温度决定离子扩散系数,化学强化时间决定DOL,一步法仅能获得相对较大的CS,而DOL不很理想,只有两种离子参与交换的二步法才有利于CS和DOL同步提高。