让步LTE 业务模式成固网宽带发力焦点

中国移动的搅局令原本就不甚盈利的固网市场雪上加霜,在宽带业务模式仍旧局限于包月套餐收费的情况下,固网接入市场的商业模式也亟待重塑。2014年是LTE全面商用的一年,三大运营商纷纷将投资重心向LTE倾斜,固网宽带的建设在一定程度上也受到了影响,中国电信、中国联通均减少了在固网上的投入。运营商固网投资缩减几乎是2014年宽带接入市场的主基调。

浙江海盐:墙材企业渐成固废利用主力

海盐县墙材企业在政策引领下，充分发挥各类墙体材料（混凝土砖类、烧结保温砖类及传统粘土多孔砖类）企业的生产特性，消化、利用各类社会生产、生活中产生的固体废弃物。2015年度，有5家企业（2家混凝土砖企业、1家烧结保温砖企业、2家烧结砖企业）达到奖励标准，共利用、消化各类固体废弃物36．41万吨。

湖南永州无管处完成固定监测站迁建前期准备工作

5月7日,湖南省永州市无线电管理处和中国铁塔股份有限公司永州市分公司签订了《永州市无线电固定监测站迁建工程施工服务合同》,标志着永州市政府固定监测站迁建前期准备工作结束,迁建工作即将启动。永州市政府固定监测站位于市政府办公大楼楼顶,铁塔高35米,于1997年建成。该铁塔由冷镀锌材料拼接而成,设计使用期限为15年至20年,目前已超期使用,存在较大安全隐患。

WiMAX将成固定宽带新宠移动市场前景暗淡

分析人士日前表示，未来几年，WiMax将在固定宽带市场崭露头角，但在移动市场的前景相对暗淡。专家称，2009年，全球固定WiMax保有量将达到2000万。目前，欧洲和美国市场已开始部署WiMax固定宽带（802.16d）。但专家认为，WiMax固定宽带市场最终还要集中在发展中国家，因为在这些市场中，宽带基础设施发展得还不够完善。

中国联通宽带用户达5829万成固定业务收入主流

截至2012年第一季度末，中国联通宽带用户总数达到5828．875户，季度新增263．7万户。2011年中国联通固定宽带业务收入同比增长18．1％，首次超过固定话音业务，已成为固定业务收入主要来源。

钢轨钢的接触疲劳伤损及实验研究

本文简要综述了钢轨钢的接触疲劳伤损特征和疲劳成因 ,探讨了提高钢轨钢使用寿命的途径 ,研究了三种中低碳贝氏体钢的接触疲劳行为。

北京云蒙山花岗岩基的岩石变形及其成因

云蒙山花岗岩基由12个侵入体组成,岩基中的片麻状花岗岩是在126±21Ma时侵入的Ⅰ型花岗岩。根据岩基中花岗岩与围岩的变形特征,确定岩基的侵位机制为底辟定位型。花岗岩中的变形组构与环绕岩基的糜棱岩带在岩基定位晚期、花岗岩浆完全结晶之前形成。由于云蒙山花岗岩基的强力定位,导致密怀变质核杂岩在燕山晚期再次发生伸展构造运动。

城乡经济差别的主要表现、成因及对策——来自郴州的研究报告

目前城乡经济差别主要表现在经济要素、经济运行过程和经济结构等方面,具有由显性差别到隐性差别、由数量差别到质量差别、由经济收入差别到文化素质差别、由领导个人差别到领导方式差别等特点,其形成原因是多方面的。我们应从心理调适、角色分工、组织措施、模式选择及法律法规的建设等五个方面采取对策,缩小城乡差别。

我国当代社会阶层成因探析

改革开放以来,我国实现了计划经济向市场经济的转化,社会经济、政治以及文化结构发生了深刻地变化,我国社会阶层结构也出现了变革,产生了一些新的社会阶层。研究我国当代新的社会阶层形成的原因,对于正确认识当前的社会阶层结构变革,认识新的社会阶层具有现实意义。

Study on the Chromatographic Fingerprint of Volatile Constituents from Acacia Honey

[Objective] The experiment aimed to study chromatographic fingerprint in volatile components of acacia honey and provide scientific evaluation and effective control on quality of acacia honey.[Method] Using solid-phase microextraction method to separate and detect volatile components and construct chromatographic fingerprint.[Result] The honey was preheated for 15 min in water bath at 40 ℃ and solid-phase microextraction 85 μmPA was used to extract in overhead air about 30 min,then put it into the injector and desorpted 3 min,which is in 230 ℃.The Supelco WaxTM10 30 m×0.25 mm×0.25 μm column and gradient heating program was the best method to separate volatile components from honey.83 fingerprint peaks were constructed,among which 17 common fingerprint peaks were comprised of chromatographic fingerprint of volatile components of acacia honey.[Conclusion] The chromatographic fingerprint could provide reference for quality control of acacia honey.

Forced convection rheoforming process for preparation of 7075 aluminum alloy semisolid slurry and its numerical simulation

A self-developed forced convection rheoforming （FCR） machine for the preparation of light alloy semisolid slurry was introduced. The microstructure characteristics of 7075 aluminium alloy semisolid slurry at different stirring speeds prepared by the FCR process were analyzed. The experimental results suggest that with the increase of the stirring speed, the mean grain size of the semisolid decreases and the shape factor as well as the number of primary grains increase. Meanwhile, the preparation process of semisolid slurry was numerically simulated. The flow characteristics of the melt in the device and the effect of the stirring speed on temperature field and solid fraction of the melt were investigated. The simulated results show that during the preparation process of semisolid slurry, there is a complex convection within the FCR device that obviously changes the temperature field distribution and solid fraction of the melt. When the convection intensity increases, the scope of the undercooling gradient of the melt is reduced and temperature distribution is improved.

Microstructural evolution during solution treatment of thixoformed AM60B Mg alloy

The microstructural evolution and kinetic characteristics were studied during solution treatment of AM60B Mg alloy prepared by thixoforming. The results indicate that the microstructural evolution includes two stages： the first stage involves rapid dissolution of eutectic β （Mg 17 Al 12 ） phase, homogenization and coarsening, and the second stage is regarded as normal grain growth consisting of primary α-Mg particles （primary particles） and secondary α-Mg grains （secondary grains）. In the first stage, the dissolution completes in a quite short time because the fine β phase can quickly dissolve into the small-sized secondary grains. The homogenization of Al element needs relatively long time. Simultaneously, the microstructure morphology and average grain size obviously change. The first stage sustains approximately 1 h when it is solutionized at 395 ℃ Comparatively, the second stage needs very long time and the microstructure evolves quite slowly as a result of low Al content gradient and thus low diffusivity of Al element after the homogenization of the first stage. The growth model of primary particles obeys power function while that of the secondary grains follows the traditional growth equation in the first stage. In the second stage, both of the primary particles and secondary grains behave a same model controlled by diffusion along grain boundaries and through crystal lattice.

张骞出使西域的历史贡献——纪念我国古代探险家、外交家张骞逝世二千一百周年

元封五年(前106年),汉武帝刘彻在“求茂才异等诏”中说;“盖有非常之功,必待非常之人。”“其令州郡察吏民,有茂才异等,可为将、相及使绝国者”。这几句话既是对未来人才的殷切期望,又是对已故人才的高度赞赏,是汉武帝用人经验的总结。汉武帝当政时期是一个人才辈出,群星灿烂的时期。张骞就是在这个时期里出现的一位“茂才异等”,在“使绝国”方面建立过非常之功的杰出的探险家和外交家。张骞,成固(今陕西城固)人,生年不详,卒于元鼎三年(前114年)。

Mechanical behavior of Al-Zn-Mg-Cu alloy under tension in semi-solid state

In order to study the hot fractures in relation to the semi-solid processing, the tensile tests of an extruded 7075 aluminum alloy which is based on Al?Zn?Mg?Cu system were carried out in the high temperature solid and semi-solid states at different strain rates. The results show that the tensile behavior can be divided into three regimes with increasing the liquid fraction. The alloy first behaves in a ductile character, and as the temperature increases, the fracture mechanism changes from ductile to brittle which is determined by both of liquid and solid, and lastly the fracture mechanism is brittle which is totally dominated by liquid. At strain rates of 1×10?4, 1×10?3 and 1×10?2 s?1, the brittle temperature ranges are 515?526, 519?550 and 540?580 °C, respectively. Two equations which are critical for tensile behavior are proposed.

Microstructure evolution and segregation behavior of thixoformed Al-Cu-Mg-Mn alloy

A commercial wrought Al-Cu-Mg-Mn alloy（2024） was thixoformed based on the recrystallization and partial melting（RAP） route, and the microstructure evolution and segregation behavior during the indirect thixoforming process were studied. The results show that fine spheroidal microstructures can be obtained by partial remelting of commercial extruded 2024 alloys without additional thermomechanical processing. During the indirect thixoforming, the stress distribution can be optimized by increasing the thickness of base region. Under three-dimensional compression stress state, the microstructures are homogeneous among different regions with no evidence of liquid segregation and micro-porosities, and the grains in the columns are deformed plastically. The distribution of tensile mechanical properties is consistent with the microstructures. Moreover, the distribution of deformation mechanism was discussed, and a technical method for improving the stress distribution was proposed.

Microstructure control of AZ31 alloy by self-inoculation method for semisolid rheocasting

A novel rheocasting process, self-inoculation method （SIM）, was developed for the microstructure control of semisolid wrought Mg alloy. This process involves mixing between liquid alloy and particles of solid alloy （self-inoculants）, subsequently pouring the mixed melt into a special designed multi-stream fluid director. The primary phase with dendritic morphology in the conventionally cast AZ31 alloy has readily transformed into near spherical one in the slurry produced by SIM from melt treatment temperature between 690 ℃ and 710 ℃ and self-inoculants addition of 3%-7%. Achievement of the non-dendritic microstructure at the higher melt treatment temperature requires more self-inoculants addition or decreases in the slope angle of fluid director. Primary phase in the slurry thus produced has attained an ideally globular morphology after isothermal holding at 620 ℃ for 30 s. The increasing holding time leads to decrease of shape factor but the coarsening of particle size. The spheroidization and coarsening evolution process of solid particles during the isothermal holding were analyzed by Lifshitz-Slyozov-Wagner （LSW） theory.

Amine-grafted on lanthanide metal-organic frameworks:Three solid base catalysts for Knoevenagel condensation reaction

A post-synthetic modification strategy has been used to prepare three solid base catalysts, including Er（btc）（ED）075（H2O）0.25 （2, btc = 1,3,5-benzenetricarboxylates, ED = 1,2-ethanediamine）, Er（btc）（PP）0.55（H20）0.45 （3, PP = piperazine）, and Er（btc）（DABCO）0.15（H2O）0.85 （4, DABCO = 1,4- diazabicyclo[2.2.2]octane）, by grafting three different diamines onto the coordinatively unsaturated Er（III） ions into the channels of the desolvated lanthanide metal-organic framework （Er（otc））. The resulting metal-organic frameworks were characterized by elemental analysis, thermogravimetric analysis, powder X-ray diffraction, and N2 adsorption. Based on its higher loading ratio of the diamine, as well as its greater stability and porosity, catalyst 2 exhibited higher catalytic activity and reusability than catalysts 3 and 4- for the Knoevenagel condensation reaction. The catalytic mechanism of 2 has also been investigated using size-selective catalysis tests.

Microstructure and mechanical properties of Mg-Zn-Y-Zr alloy prepared by solid state recycling

Machined chips of Mg-Zn-Y-Zr alloy were consolidated by cold pressing and then hot extrusion under various processing temperatures and extrusion ratios. The results show that the microstructure of the chip-extruded alloy is marked by a large number of recrystallized grains and some unrecrystallized grains, which results in high strength but low ductility at temperatures below 320 ℃. With increasing processing temperature up to 360 ℃, entirely recrystallized and equiaxed grains are obtained. Mg-Zn-Y-Zr alloy with low strength but high ductility is obtained compared with the alloy processed at low temperature. At 420℃, coarse and equiaxed grains are formed, which results in the drastic decrease of mechanical properties. With increasing extrusion ratio from 8 to 16, the grain refinement is more obvious and the mechanical properties at room temperature are improved effectively. However, the yield strength and ultimate tensile strength are improved a little with further increasing extrusion ratio.

Simulation of temperature field and metal flow during continuous semisolid extending extrusion process of 6201 alloy tube

A continuous semisolid extending extrusion （CSEP） method was proposed. Temperature field and metal flow during continuous semisolid extending extrusion process of 6201 alloy tube were studied. During the process, the temperature in the roll-shoe cavity decreases gradually, and the isothermal lines of the alloy deviate from the shoe side to the work roll side in the roll–shoe gap. Metal flow velocity decreases gradually from the surface of the work roll to the surface of the shoe. In the extrusion mould, alloy temperature decreases gradually from the entrance to the exit and from the center to the sidewall of the mould. The extending cavity is radially filled with the alloy. The flow lines in the tube corresponding to the centers of the splitflow orifices and the welding gaps are dense, and the corresponding harness values are high; there are 8 transitional bands between them. In order to prepare 6201 alloy tubes with good surface quality, the pouring temperature from 750 ℃ to 780 ℃ was suggested.