离子交换树脂法制备高纯超细氢氧化镁

以强碱性阴离子树脂作为沉淀剂,采用离子交换法制备了高纯超细的氢氧化镁粉体,就离子交换反应过程中的反应温度、反应时间、MgCl2浓度等条件对Mg（OH）2粒径的影响进行了探讨,并利用扫描电镜、微机差热天平、X射线衍射仪对产物进行了表征,实验结果表明,在氯化镁溶液浓度为0．1mol／l,反应温度为60℃,反应时间为16h的条件下可制备出形貌规则、分散性较好的六方片状氢氧化镁,平均粒径可达到100nm左右。     

纳米氢氧化镁粉体的制备及热分解动力学研究

以氯化镁和尿素为原料,采用均匀沉淀法制备出厚度约为20 nm的片状纳米氢氧化镁粉体。利用热重分析法对片状纳米氢氧化镁粉体在不同升温速率下的热分解动力学进行研究,以期深入认识由纳米氢氧化镁粉体热分解得到纳米氧化镁粉体过程的物理化学本质。分别采用Coats-Redfern方程和Dolye方程,对热重分析数据进行了处理和拟合,得到了片状纳米氢氧化镁粉体热分解反应属于Avrami-Erofeev(n=1)的成核和生长为控制步骤的反应机理,其表观活化能E=131 kJ/mol,指前因子A=1.56×1010。     

氢氧化铝镁复合材料的研制

本文研究了两种制备氢氧化铝镁复合材料的方法：一种是采用氯化镁溶液与氢氧化钠溶液进行中和反应,制取氢氧化镁,然后以氢氧化镁料浆为种子,加入铝酸钠溶液中进行晶种分解得到产品;另一种是将硝酸铝和氯化镁按一定比例配制成混合溶液,再缓慢加入氢氧化钠溶液作为沉淀剂制取产品。经过检测,两种方法均可制备得到纯相的氢氧化铝镁复合材料。     

MgCl_2添加方式对Mg(OH)_2形貌及粒度分布的影响

氢氧化镁作为一种无卤阻燃剂,在聚合物阻燃领域具有重要的前景。采用反向沉淀法制得纳米级氢氧化镁粉体,研究了氯化镁添加方式对氢氧化镁粒度分布及团聚状态的影响,并通过热红外联用技术对其热解规律进行了分析。实验结果表明,氯化镁添加方式对氢氧化镁粒度分布及团聚状态有显著的影响;分4次加入氯化镁溶液所得氢氧化镁的粒度分布最均匀,小粒子所占的比例最大,不容易发生团聚现象。     

片状纳米级氢氧化镁粉的制备工艺与分散机理研究

氢氧化镁粉的超细化和高分散性是充分发挥其在聚合物材料中的阻燃性的前提。对片状纳米氢氧化镁粉的制备工艺以及几种表面活性剂的种类、用量对纳米氢氧化镁粉的分散性的影响进行了研究，并通过扫描电子显微镜（SEM）、红外光谱（FTIR）对其进行了表征。研究结果表明，制备片状纳米氢氧化镁的最优工艺条件是：镁液中Mg^2＋的初始浓度为22．75g／L，沉淀剂用20％的NaOH溶液，反应温度为50℃，反应时间为5min。SEM分析表明：在此条件下制得的片状纳米级氢氧化镁粉片径100nm左右，厚10nm左右，但是颗粒之间团聚严重，团聚颗粒达到微米级。使用硅烷FR-693、钛酸酯YB-502和聚乙二醇对氢氧化镁进行原位改性可以提高其分散性。硅烷FR-693、钛酸酯YB-502和聚乙二醇的最佳用量分别为氢氧化镁质量的1．5％，1．5％，0．75％。FTIR分析表明，3种改性剂都可以吸附在氢氧化镁颗粒表面并形成化学吸附。其中硅烷FR-693与粉体表面形成Si-O-Mg化学键合，钛酸酯YB-502与粉体表面形成Ti-O-Mg键合。     

针状纳米氢氧化镁的形貌控制

以氯化镁和氢氧化钠为反应物，添加表面活性剂十二烷基苯磺酸钠（SDBS），在水溶液中利用反向沉淀法制备针状纳米氢氧化镁粉体，其直径为9～12nm，长度为40～110nm。并应用X射线粉末衍射仪（XRD）、场发射扫描电子显微镜（FESEM）、高分辨透射电子显微镜（HRTEM）对所制备粉体的晶型结构、粒度、形貌进行表征。同时讨论了表面活性剂／分散剂对纳米氢氧化镁粉体形貌的影响。     

丙烯酸改性氢氧化镁晶须的制备及研究

以MgCl2·6H2O为原料,氨水和氢氧化钠为混合沉淀剂,丙烯酸为表面改性剂,制备了高纯度的纤维状纳米氢氧化镁晶须.研究了丙烯酸的加入量,反应温度及氢氧化钠溶液的浓度对产物分散性、结晶及产率的影响,同时对产物进行SEM,TEM以及XRD分析.结果表明:控制氯化镁浓度为2mol/L,氢氧化钠溶液的浓度为2.2mol/L,丙烯酸的添加量为3%(质量分数),反应温度为10℃,在此条件下,制备出了长度在50～150nm,直径在8～15nm的高纯纳米氢氧化镁晶须.     

变温结晶法制备高分散性纳米氢氧化镁

以轻烧粉与氯化铵反应得到的精制氯化镁溶液为原料,氨气为沉淀剂,通过改变反应温度控制反应体系过饱和度,变温反应制备出高分散纳米氢氧化镁,并利用扫描电镜(SEM)、X射线衍射(XRD)和激光粒度分布仪对产品进行了表征。实验研究了变温反应与恒温反应产品形貌和粒径的区别,结合液相体系中OH-浓度随反应温度的变化过程,分析讨论了变温法制备高分散纳米氢氧化镁的机理。     

立方纳米氧化镁的制备及形貌表征

利用直接沉淀法得到片状氢氧化镁前驱体,再结合煅烧法得到立方纳米氧化镁;为优化实验条件,讨论氢氧化镁前驱体及氧化镁的形貌影响因素。实验结果表明:当氢氧化钠的物质的量浓度为0. 5 mol/L、镁盐物质的量浓度为0. 4 mol/L时,可得到分散性较好的片状氢氧化镁前驱体;当氯化镁的纯度较高时,氢氧化镁结晶度进一步提高,呈现出分散均匀的花瓣状薄片形貌;煅烧温度控制在1 150℃时,所得到的立方纳米氧化镁分散性较好。     

球形氢氧化镁的制备及其晶体生长动力学

制备花状球形氢氧化镁粉体,研究了几种关键因素对镁回收率的影响和氢氧化镁的晶体生长动力学.结果表明,随着反应溶液中Mg~(2 )初始浓度和pH值的提高,镁的回收率提高;提高反应温度使镁的回收率提高,但当温度超过60℃后,反应溶液中氨的大量挥发使其pH值迅速降低,因而镁回收率下降;陈化可以提高镁的回收率,当陈化时间超过60 min后因镁已完全沉淀,回收率不再提高.在最佳工艺条件下用氨法制备的氢氧化镁颗粒为花状球形,形状规则,分散性好,粒度均匀,粒径约2μm,单片厚度约30 nm.晶体生长动力学研究表明,析出Mg(OH)_2晶体的质量和Mg(OH)_2晶粒平均粒径随着时间呈指数增长.     

Effect of Permeable Crystalline Material on Steel Reinforcement Corrosion of Concrete

Permeable crystalline materialcan permeate into pores and cracks of concrete and catalyze the reaction between Ca(OH) 2and unhydrated cement to generate a great quantity needle non-soluble crystals, which can stop up the pores and cracks of concrete, and increase the impermeability of concrete. This paper reported the results of a study conducted to evaluate steel reinforcement corrosion of concrete specimens uncoated and coated with permeable crystalline material as well as mixed with the permeable crystalline material. The properties evaluated for corrosion test were water impermeability, water absorption, compressive strength and potential. The results of water impermeability, water absorption, compressive strength clearly showed that the permeable crystalline material could prohibit water, any soluble salts and moisture from penetrating the concrete to cause corrosion, leaking, and other problems, and it did increase the compressive strength, which was favorable for protection of corrosion of reinforcing steel. Moreover, it was concluded from the potential-time curve that the steel reinforcement of uncoated specimen was in the state of activation whereas that of other specimens coated and mixed with the permeable crystalline material was in the state of inactivation. Above all, it was indicated that the permeable crystalline materialis very effective to protect the steel reinforcement of concrete from corrosion.     

The Research and Application About "Dry Peeling Off" Technology for Airplane Surface Paint Layer

In this paper, the principle of spurting take off lacquer were introduced; and with orthogonal method the unsaturate polyester was prepared ;it was easy to peel airplane paint layer off with this material and equipment.     

Quality Study of Honeycomb Core Shaping Without Wax Stabilization

Sandwich panels utilizing honeycomb cores result in lightweight, high-strength units that are very rigid. Indeed, they give honeycomb panels the best strength-to-weight ratio of any construction type available. Conventionally, the wax is poured into the cell of the core to strengthen the structure and prevent the core from being crushed during milling. Much time and labor is required to wax, mill, and clean the cores. In this study, the process of pouring wax into the core was skipped. In other words, the cutter directly milled the core. Experiments showed that the compressive strength of the core produced without wax stabilization was only 3% lower than that of cores produced using the traditional method. In addition, the drum peel strengths of cores produced without wax stabilization were 38.4% higher than cores produced using the traditional method, in which residual wax seriously polluted the adhesive. It was also found that eliminating the wax process can reduce costs.     

In-process thermal treatment of polylactic acid in fused deposition modelling

Polylactic acid (PLA) is one of the most widely used open source fused filament fabrication materials due to its ease of extrusion, biodegradability, and mechanical strength. The mechanical strength of PLA largely depends on the proper growth of its semi-crystalline structure, which can be severely impaired by a low rate of crystallization, particularly in open source printers. This can be further aggravated by the non-uniform thermal distribution of heat that causes improper curing among the extruded beads of the printing material. As a result, PLA printed on open source printers does not achieve the best mechanical properties. This research, for the first time, proposes an additive-free solution implemented through a detailed set of experimentation to improve the curing rate through in-process temperature variations to cure the joints among the beads. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy is used to confirm the improvements in the bead joints. This work is conducted in two phases of experiments. In the first phase, a full factorial ANOVA is used to investigate various process parameters and the important variables are used in the second phase to print test specimens in four different sets.     

Investigation of the Corrosion Behaviors of HVOF-Sprayed Carbide Cernet Coatings in Molten Al-Zn-Si Alloy Bath

In continuous hot-dip galvanization process the corrosion and chemical stability of the sink roll in the galvanizing bath are important problem which effects on the quality and productivity. In order to protect the sink roll the carbide cermet and/or ceramic coatings were deposited on the surface of the sink roll. The WC-, Cr3 C2-cermet coatings were deposited by high velocity oxygen fuel (HVOF) spray, respectively. The coating samples were immersed in molten Zn-alloy containing 50 wt % aluminum at 833 K for 24 hr and 144 hr, respectively. The inter-diffusion and inter-reaction of Zn, Al and elements in coating and corrosion behaviors of these coatings were investigated by XRD, SEM and EPMA etc. The corrosion mechanisms of the carbide cermet coatings and ceramic coatings in molten High Al-Zn-alloy were approached.     

Fundamental study of adhesion of ice to cooling solid surface (Discussion on influence of copper oxide layer on ice adhesion force)

In many situations, ice often adheres to a cooling solid surface, frequently causing serious accidents. It is critical to clarify the mechanism of ice adhesion to the cooling surface in order to prevent ice adhesion. In a past study, the shearing stresses of two kinds of test plates with a copper surface having the higher thermal conductivity were measured. The shearing stress corresponds to ice adhesion force. Both shearing stresses were significantly different; however, the cause remains unclear.Therefore, the present study focuses on an oxide layer as the main factor causing the difference of both shearing stresses; the influence of the oxide layer formed on shearing stress was discussed. And in the removal and reformation processes of the oxide layer, the time variation of the shearing stress was clarified. Moreover, the relationship between the state of the copper surface and the shearing stress was also clarified by surface analysis.     

重塑标准推行格局 推动LED照明的普及（英文）

正When you are enjoying the green,energy-saving and healthy lighting of IKEA LED luminaire,you may not realize that most of IKEA’s LED bulbs are produced by the LED luminaire smart manufacturing system of Hangzhou Zhongwei Photoelectricity CO.,LTD(ZVISION).No longer enclosed in the laboratory,the product standards are brought into the factory workshop and even to the entire production process.Thus,the standards are promoted and applied in a favorable way by enterprises,benefitting consumers with high quality products.     

Chinese Experts Contribute to ISO＇s New Toy Standards

正The international standard,ISO 8124-6,Safety of toys–Part 6:Certain phthalate esters in toys and children’s products,was officially issued by ISO worldwide on August 15.It was the first time for Chinese experts to lead the ISO standard development in toys industry.The standard was drafted by a group of Chinese experts from SAC/TC for toys and relevant Chinese departments and finally completed by a dedicated international group of experts.ISO 8124-6 makes a substantive breakthrough in the aspects of the scope of toys,limitation of plasticizer types,control of test cost,accuracy of test,operation convenience,etc.,offering the operational guidance for toy manufactures and testing laboratories.     

中国质量(北京)大会(英文)

正Themed on"quality,innovation,development",the first China Quality Conference(Beijing)was held in the Great Hall of the People on September 15.Chinese Premier Li Keqiang delivered an important speech at the conference.State Councilor Yang Jing and Wang Yong attended the conference with over 600 domestic and international representatives from foreign,regional and international quality organizations     

National Working Meeting on Land and Resources Standardization

正The National Working Meeting on Land and Resources Standardization was held in Beijing on July 15,2014.Wang Min,the Deputy-Minister of the Ministry of Land and Resources,and Yin Minghan,the Chief-Engineer of SAC addressed the meeting.Representatives from relevant competent departments and technical committees were present.The meeting aims to summarize work,discuss existing problems and make clear working thoughts,promoting standardization work of land and resources to a new level.Wang Min pointed out that the standardization work of land and resources should be centered on the basic principles of"protecting land and resources dutifully,intensively and economically utilizing land and resources,and making all-out efforts to safeguard the public’s rights and interests",highlighted the