葡聚糖修饰漆酶的制备及其催化特性和稳定性

将经NaIO₄氧化处理的葡聚糖（500×10³）连接在漆酶分子上以提高漆酶在酸性溶液环境中的稳定性。HPLC和SDS-PAGE分析表明葡聚糖修饰漆酶的分子量在200×10³以上。荧光光谱和圆二色性光谱分析表明修饰漆酶保持了天然漆酶的三级和二级结构。酶催化反应显示修饰漆酶与天然漆酶具有类似的底物亲和性和催化活性，而其在酸性条件下的稳定性显著提高。通过葡聚糖修饰使得漆酶在pH 3,50℃下的酶活半衰期从0. 07 h提高到17. 1 h，在含30%（体积）乙腈, pH 3下的酶活半衰期从0. 11 h提高到10. 3 h。在不同pH下测定修饰漆酶在216 nm处的圆二色性光谱，结果显示偶联葡聚糖增强了漆酶分子的结构稳定性，提高了其在高温及有机溶剂存在下的催化活性。     

Preparation and application of polybenzoxazine adsorption resin

The synthesis and application of polybenzoxazine adsorption resin was studied. First, the precursor was synthesized by the solventless method. And then a kind of spherical and granular polybenzoxazine resin was obtained using reverse‐phase suspension polymerization technique in the process of solidification. Besides, the influence of dispersion medium, the volume ratio of precursor to medium, the solidification temperature, and the agitation speed were studied in detail in the process of polymerization. Second, the spherical shape of the polybenzoxazine resin was identified by scanning electronic microscope and the thermal stability of resin was measured by thermogravimetric analysis. Finally, the adsorption capacity of the spherical resin on pyridine was studied in cyclohexane systems. The correlation coefficient of Langmuir adsorption constant temperature line was bigger than 0.99, which indicated that the equilibrium sorption date was coincident with the Langmuir isotherm equation. And the saturated adsorptive capacity of dried resin achieved 222.2 mg g^?1. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

聚丙烯的晶型及常用成核剂

介绍了α,β这两种最重要的聚丙烯的结晶形态及性能特点,阐述了常用的α晶型成核剂(包括无机成核剂、有机成核机和高分子成核剂)及β晶型成核剂的结构特点和使用性能,并结合当前的工作展望了成核剂的发展方向。     

Processing and characterization of particles reinforced SiOC composites via pyrolysis of polysiloxane with SiC or/and Al fillers

Polysiloxane loaded with SiC as inert filler, and Al as active filler, was pyrolyzed in nitrogen to fabricate SiOC composites, and the processing and properties of the filled SiOC composites were investigated. Adding SiC fillers could reduce the linear shrinkage of filler-free cured polysiloxane in order to obtain monolithic SiC/SiOC composites. The flexural strength of SiC/SiOC composites reached 201.3 MPa at a SiC filler content of 27.6 vol.%. However, SiC/SiOC composites exhibited poor oxidation resistance, thermal shock resistance and high temperature resistance. Al fillers could react with hydrocarbon generated during polysiloxane pyrolysis at 600 °C and N₂ at 800 °C to form Al₄C₃ and AlN, respectively. The volume expansions resulting from these two reactions were in favor of the reduction in linear shrinkage and the improvement in flexural strength of SiC/SiOC composites. The flexural strength of Al-containing SiC/SiOC composites was 1.36 times that of SiC/SiOC composites without Al at an Al filler content of 20 vol.%. The addition of Al fillers remarkably improved the high temperature resistance and oxidation resistance of SiC/SiOC composites, but not thermal shock resistance.     

Coupling of nuclear heating reactor with desalination process

A seawater desalination plant using a nuclear heating reactor (NHR) coupled with the multi-effect distillation (MED) process was developed by the Institute of Nuclear Energy Technology, Tsinghua University, China. The seawater desalination plant was designed to supply potable water demand to some coastal location or island where both fresh water and energy sources are severely lacking. The NHR design possesses intrinsic and passive safety features, which was demonstrated by the NHR-5 experiences. The intermediate circuit and steam circuit were designed as the safety barriers between the NHR and MED desalination systems. With the power range of the heating reactor within 10 to 200 MWt, the desalination plant could provide 8,000 to 160,000 m³/d of potable water of appropriate quality. The design concept and parameters, safety features, and comparative investigation of coupling schemes are presented in the paper.     

火柴胶质量改进的方向

火柴，在20世纪80年代以前，是一个使用极其广泛的商品。直至今日，在城市虽已大部被汽油或燃气打火机所取代，但在农村却仍有广阔市场。展望未来，很有可能因为石油资源的日益减少和价格的不断上涨。火柴还将可能有它再度辉煌的一日。     

Dynamic viscoelasticity of low‐density polyethylene/in‐situ‐grafted carbon black composite

The study on the dynamic viscoelastic properties of grafted carbon black (g‐CB) filled low‐density polyethylene (LDPE) was carried out. Because of formation of CB networking, the characteristic modulus plateau and loss tangent arc appears. Addition of grafting monomer like butyl acrylate (BA) and acroleic acid (AA) enhances the interaction between particles and matrix due to accelerated formation of micronetworking in the composites induced by forming branch chains of AA and BA with multiunit. The decrease of the temperature corresponding to α_c mechanical relaxation together with AA (BA) addition given by the position of loss tangent (tan δ) peak for LDPE is owed to the formation of long‐chain polymer grafted between CB and the matrix, which facilitates the slip of the lamella of LDPE. The influence of maleic anhydride (MA) on enhancing interaction between LDPE and CB is not so pronounced, as compared with AA and BA because of no formation of long chain between CB particle and polymer matrix. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4127–4132, 2006     

差别化涤纶短纤维的生产技术经济

以有光涤纶 1 .33dtex缝纫线专用短纤维为研究对象 ,借助化纤成形技术和经济学原理 ,从技术装备、产能匹配等着手 ,研究了加工制造差别化涤纶短纤维的技术适应性、差别化成本及其主要构成。提出差别化纤维研发中聚合 -纺丝的几种匹配模式 ,以及合成纤维及其品种相互替代的潜在可能性。对大型生产装置、装备的柔性化与专用性的相互兼容进行了探讨     

EDTA在尿素换热设备清洗中的应用

草酸法清洗换热设备垢层时对设备腐蚀严重。EDTA能与积垢中的铁离子反应生成溶于水的络合离子,达到清洗积垢的目的,对设备腐蚀程度也小,通过EDTA、Fe含量的变化可判断清洗程度。     

振动筛板槽中液滴分散动力学的研究——(Ⅱ)实验结果及Monte-Carlo模拟技术的应用

本文根据前文(I)报的理论分析,采用Monte-Carlo方法对实验数据进行模拟.液滴直径的测量采用照相法及透光法.所测得的液滴直径分布数据及平均液滴直径的数据,在微机上进行拟合归纳,得到了振动筛板槽中液滴直径分布模型及液滴平均直径的关联式.模型计算结果与实测值拟合较好.应用Monte-Carlo模拟技术对液滴破碎和凝聚这一随机过程进行了模拟及参数估计,得到了液滴破碎速率及凝聚速率参数.