移动视频服务在主流市场普及的十大因素

2006年，宽带及网络多媒体的成功应用令移动网络开始广泛应用于视频服务领域。各地的企业和消费者在日常生活中成功使用移动视频服务的例子多不胜数，使用时间远远超过十亿分钟，同时带来了逾十亿美元的收入。如果运营商、集成商、广播机构及内容提供商实施一系列措施以进一步推广这些服务的应用，仅移动视频一项，就将在2007年增长三倍以上。以下就是服务提供商现已实施的举措。     

浅析移动多媒体的货币化进程

过去的一年，流行的视频网站、兴趣社区（Communities of interest）、社交网络的普及和个性化需求出现成倍增长。虽然以分钟计算，多媒体服务和使用率均创下历史新高，但服务提供商和内容提供者仍然在根据消费者和企业的需求，不断调整着他们的收益和推出新服务模式。     

再造简约优雅之风ASUS U系列设计师专访

当几年前，苹果CEO乔布斯在台上向全世界展示了轻薄如蝉翼的MacBookAir的时候，苹果向世界证明自己用“简约性感”的设计征服了消费者。     

Nitrosamine carcinogens also swim in chlorinated pools

Highly carcinogenic N-nitrosodialkylamine (nitrosamine) disinfection byproducts were quantified in chlorinated swimming pools, hot tubs, and aquaria. N-Nitrosodimethylamine, the most abundant nitrosamine detected, was measured in swimming pools and hot tubs at levels up to 500-fold greater than the drinking water concentration of 0.7 ng/L associated with a one in one million lifetime cancer risk. Temperature, enclosure, amine and nitrite precursor loading, and the use of disinfection schemes with reduced chlorine doses contributed to statistically significant variability in its occurrence. N-Nitrosodibutylamine and N-nitrosopiperidine were also detected but together represented <5% of the total analyte distribution. The presence of N-nitrodimethylamine at levels comparable to N-nitrosodimethylamine points to a competition between the nitration and nitrosation of amines in chlorinated recreational waters. Since nitrosamines can cause bladder cancer, the significance of our measurements needs clarification with respect to recent epidemiological results that are suggestive of a link between swimming in chlorinated pools and bladder cancer.     

FTTH正在走出实验室

多年以来,光纤到家（FTTH）一直在商用化的边缘徘徊。虽然进行了大量的试验和一定规模的部署,但是经济性和技术性的问题使FTTH一直难以向广泛商用化迈出新的一步。一个重要的原因是,传统电话公司和有线网络公司对自己的传统网络投入了如此巨大的人力和物力,以致不可能使他们心甘情愿地进行如此剧烈的变革,至少他们担心现有的核心业务会受到严重的威胁。正在走向前台的新一代网络提供者——“第三种网络提供者”,则与众不同,他们的前途决定于是否能够为客户提供价格合理的高质量新型宽带业务。由于他们是从零开始的,而且在大多数…     

双功能化、双重响应聚（N-异丙基丙烯酰胺）基微凝胶的研究

为制备具有特殊层次结构的多功能化微凝胶,利用N-异丙基丙烯酰胺（NIPAM）为温敏性单体、甲基丙烯酸（MAA）为pH敏感单体、聚乙二醇甲基丙烯酸酯（PEGMA）为反应性稳定剂,通过沉淀聚合合成了内部富含羧基、表面富含羟基的一系列共聚物微凝胶。利用滴定法测定了微凝胶中羧基的含量。透射电镜和动态光散射表明得到的微凝胶几乎是单分散的。变温动态光散射和浊度测定结果表明,所制备的微凝胶具有良好的pH-响应性,随温度改变呈现两级体积相转变。     

Comparison of byproduct formation in waters treated with chlorine and iodine: relevance to point-of-use treatment

Due to their efficacy in deactivating a range of microbial pathogens, particularly amoebic cysts, iodine-based disinfectants have been a popular option for point-of-use (POU) drinking water disinfection by campers, the military, and rural consumers in developing countries. Recently, concerns regarding the formation of cytotoxic and genotoxic iodinated disinfection byproducts (I-DBPs) have arisen during chloramine disinfection of iodide-containing waters in the developed world; similar concerns should pertain to iodine-based POU disinfection. Because there are alternative POU disinfection techniques, including chlorine-based disinfectants, this paper compared disinfection byproduct formation from a range of iodine-based disinfectants at their recommended dosages to chlorination and chloramination under overdosing conditions. Just as chloroform was the predominant trihalomethane (THM) forme during chlorination or chloramination, iodoform was the predominant THM formed during iodination. Conditions fostering THM formation were similar between these treatments, except that THM formation during chlorination increased with pH, while it was slightly elevated at circumneutral pH during iodination. Iodoform formation during treatment with iodine tincture was higher than during treatment with iodine tablets. On a molar basis, iodoform formation during treatment with iodine tincture was 20-60% of the formation of chloroform during chlorination, and total organic iodine (TOI) formation was twice that of total organic chlorine (TOCl), despite the 6-fold higher oxidant dose during chlorination. Based upon previous measurements of chronic mammalian cell cytotoxicity for the individual THMs, consumers of two waters treated with iodine tincture would receive the same THM-associated cytotoxic exposure in 4-19 days as a consumer of the same waters treated with a 6-fold higher dose of chlorine over 1 year. Iodoacetic acid, diiodoacetic acid, and other iodo-acids were also formed with iodine tincture treatment, but at levels <11% of iodoform. However, testing of a Lifestraw Personal POU device, which combines an iodinated anion exchange resin with activated carbon post-treatment, indicated minimal formation of I-DBPs and no iodine residual. Although N-nitrosamines have been associated with oxidant contact with anion exchange resins, N-nitrosamine formation rapidly declined to low levels (4 ng/L) using the Lifestraw device after the first few flushes of water.     

岩石地基锚桩锻锤基础的动力性能试验研究与设计实践

引言过去,建筑在岩石地基上冲击振动能量较大的缎锤基础,设计时一般采用加深锤基础的埋置深度和加大基础底面积的办法来满足锻锤基础设计的振动要求。这势必挖去很大一部分岩体,然后再用钢筋混凝土浇注起来,这样既费时、费工又费材料。本文提出在岩石地基上采用锚桩的方法将锻锤基础与岩体较为牢固地联成整体,充分发挥岩石地基的作用改善锻锤基础的工作条件,就可以满足锤基础的振动要求。从而减小锤基础的埋置深度和底面积尺寸。这样既减少工程量、节约投资又能加快施工进度。然而岩石地基     

Formation of N-nitrosodimethylamine (NDMA) from dimethylamine during chlorination

Chlorine disinfection of secondary wastewater effluent and drinking water can result in the production of the potent carcinogen N-nitrosodimethylamine (NDMA) at concentrations of approximately 100 and 10 parts per trillion (ng/L), respectively. Laboratory experiments with potential NDMA precursors indicate that NDMA formation can form during the chlorination of dimethylamine and other secondary amines. The formation of NDMA during chlorination may involve the slow formation of 1,1-dimethylhydrazine by the reaction of monochloramine and dimethylamine followed by its rapid oxidation to NDMA and other products including dimethylcyanamide and dimethylformamide. Other pathways also lead to NDMA formation during chlorination such as the reaction of sodium hypochlorite with dimethylamine. However, the rate of NDMA formation is approximately an order of magnitude slower than that observed when monochloramine reacts with dimethylamine. The reaction exhibits a strong pH dependence due to competing reactions. It may be possible to reduce NDMA formation during chlorination by removing ammonia prior to chlorination, by breakpoint chlorination, or by avoidance of the use of monochloramine for drinking water disinfection.     

Microchip:2012关注物联网、智能电网和通信技术

技术继续向我们生活的方方面面进一步渗透,包括计算、工业/制造、移动技术(例如电话和平板电脑)、医学进步以及可再生能源(例如电动汽车)。尽管隶属这些行业的应用已经颇为丰富,但仍有巨大的扩展空间。半导体继续充当所有这些扩展领域的创新推动力。一般来说,半导体市场的成长基本都围绕着给生活中涉及的设备添加智能。连通性正是可以发展和创新的重要领域之一,这是因为嵌入式系统越来越多,使之相互之间能够互相交流的需求日益强烈。