2,2,6,6-四甲基-4-甲氧基哌啶氮氧自由基制备方法的改进

阐述了一种制备 4 -甲氧基 -2 ,2 ,6 ,6 -四甲基哌啶氮氧自由基的改进方法 :以四氢呋喃为溶剂 ,0℃时 ,在N2 的保护下和NaH的存在下 ,2 ,2 ,6 ,6 -四甲基 -4 -羟基哌啶氮氧自由基与MeI在室温反应 5h。分离混合物 ,得到粘稠状红色液体 ,加入正己烷 ,在 -2 0℃条件下储存 ,结晶出针状深红色的晶体。熔点 :4 2～ 4 3℃ ,产率 70 %以上     

SE-I型混凝剂在水处理中的应用

利用透射电镜和微孔滤膜超滤法研究了SE -I和PAC混凝剂的结构形貌和相对分子质量分布情况 ;比较了SE -I和PAC混凝处理油田含油废水、煤矿矿井废水和水库水的效果。实验结果表明 ,SE -I较PAC具有更大的枝化度和相对分子质量 ,体现在水处理效果上是SE -I较PAC有更好的除油、除浊、去除COD和脱色效果。SE -I型混凝剂是一种高效水处理剂     

吸收式制冷技术在尿素余热回收中的应用

简单介绍了热水型溴化锂吸收式制冷机组的原理、特点,论述了利用尿素系统产生的余热通过制冷机组制取冷媒水用于冷却碳丙液,降低了碳丙液温度.提高了变换气中二氧化碳的脱除效果,降低了电耗.     

Experiments of a prototype wind-driven reverse osmosis desalination system with feedback control

A prototype wind-powered reverse osmosis desalination system was constructed and tested on Coconut Island off the northern coast of Oahu, Hawaii, for brackish water desalination. The system has four major subsystems: a multi-vaned windmill/pump, a flow/pressure stabilizer, a reverse osmosis module, and a control mechanism. The feedback control mechanism, developed by this study, allowed this prototype system to be operated satisfactorily under mild ambient wind of 5 m/s or less. No auxiliary power source was needed. The system operational data showed that at an average wind speed of 5 m/s, brackish feedwater at a total dissolved solids concentration of 3000 mg/1 and at a flow rate of 13 1/min could be processed by this system. The average rejection rate of this prototype system was 97% and the average recovery ratio was 20%. The energy efficiency of the system was measured at 3 5%, which is comparable to the typical energy efficiency of well-operated multi-vaned windmills. Generally, the system's energy efficiency decreases as wind speed increases.     

Rheology of poly(propylene)/clay nanocomposites

The linear and nonlinear shear rheological behaviors of poly(propylene) (PP)/clay (organophilic‐montmorillonite) nanocomposites (PP/org‐MMT) were investigated by an ARES rheometer. The materials were prepared by melt intercalation with maleic anhydride functionalized PP as a compatibilizer. The storage moduli (G′), loss moduli (G″), and dynamic viscosities of polymer/clay nanocomposites (PPCNs) increase monotonically with org‐MMT content. The presence of org‐MMT leads to pseudo‐solid‐like behaviors and slower relaxation behaviors of PPCN melts. For all samples, the dependence of G′ and G″ on ω shows nonterminal behaviors. At lower frequency, the steady shear viscosities of PPCNs increase with org‐MMT content. However, the PPCN melts show a greater shear thinning tendency than pure PP melt because of the preferential orientation of the MMT layers. Therefore, PPCNs have higher moduli but better processibility compared with pure PP.© 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2427–2434,2004     

TiCl4水解法制备纳米TiO2粉体

以TiCl4为原料,采用低温液相水解法制备了纳米TiO2粉体,着重研究了Ti4 的浓度和添加聚乙烯吡咯烷酮(Polyvinylpyrrolidone,PVP)对产物的晶相、颗粒大小和表面形貌的影响.使用XRD,TEM,SEM,激光粒度测试仪对样品进行了表征.结果表明,Ti4 浓度影响TiO2粉体的相转变温度,随着Ti4 浓度的升高金红石相的含量逐渐升高,但粉体分散性变差;添加PVP提高了所得TiO2粉体的分散性,粒径降低为40～50 nm左右,并改善了粉体的形貌.     

Effect of structural and electrochemical properties of different Cr-doped contents of Li[Ni1/3Mn1/3Co1/3]O2

Layered Li[Ni_(1−x)/3Mn_(1−x)/3Co_(1−x)/3Cr_x]O₂ materials with x = 0, 0.01, 0.02, 0.03, 0.05 are prepared by a solid-state pyrolysis method. The oxide compounds were calcined with various Cr-doped contents, which result in greater difference in morphological (shape, particle size and specific surface area) and the electrochemical (first charge profile, reversible capacity and rate capability) differences. The Li[Ni_(1−x)/3Mn_(1−x)/3Co_(1−x)/3Cr_x]O₂ powders were characterized by means of X-ray diffraction (XRD), charge/discharge cycling, cyclic voltammetry, and SEM. XRD experiment revealed that the Li[Ni_(1−x)/3Mn_(1−x)/3Co_(1−x)/3Cr_x]O₂ (x = 0, 0.01, 0.02, 0.03, 0.05) were crystallized to well layered -NaFeO₂ structure. The first specific discharge capacity and coulombic efficiency of the electrode of Cr-doped materials were higher than that of pristine material. When x = 0.02, the sample showed the highest first discharge capacity of 241.9 mAh g⁻¹ at a current density of 30 mA g⁻¹ in the voltage range 2.3–4.6 V, and the Cr-doped samples exhibited higher discharge capacity and better cycleability under medium and high current densities at room temperature.     

Rheology studies of polyethylene/chemical blowing agent solutions within an injection molding machine

An in‐line capillary rheometer nozzle equipped to a conventional reciprocating 55‐ton injection molding machine was used to study the viscosity of single phase low density polyethylene (LDPE)/chemical blowing agent (CBA) solutions under high shear rate in the concentration range of 0 to 5 wt%. The steady shear viscosity of LDPE with endothermic and exothermic chemical blowing agents was measured for shear rates ranging from 170 to 200,000 s^?1 and under pressure conditions up to 36 MPa. Pressure‐volume‐temperature (pvT) measurements were determined to account for the pressure effects and the changes of the free volume during processing. The viscosity reduction of the polymer‐CBA solution was found to be dependent on the concentration of the chemical blowing agent and melt pressure. A model based on a simplified Cross‐Carreau model, incorporating the pvT behavior of LDPE, and the free volume concept was proposed to estimate the viscosity reduction resulting from the addition of a chemical blowing agent. The model employs a scaling method based on concentration‐dependent and pressure‐dependent shift factors to collapse the viscosity measurement to a master curve at each temperature. POLYM. ENG. SCI., 45:1108–1118, 2005. © 2005 Society of Plastics Engineers     

Novel nitrogen‐containing epoxy resin. II. Cure kinetics by differential scanning calorimetry

The isothermal and nonisothermal cure behaviors of a novel nitrogen‐containing epoxy resin (XT resin) were studied by differential scanning calorimetry (DSC). Various kinetic parameters and details of cure process were obtained based on the Avrami theory. The results indicated that Avrami method is suitable for calculating the kinetic parameters up to the gel point at least. The apparent activation energy (E_a) for isothermal cure process was in agreement with that for nonisothermal cure process. E_a value in the early stage (78.5–81.0 KJ mol^?1) was about three times than that in the later stage (23.3–26.5 KJ mol^?1). The kinetic results from Avrami theory may present a combined effect of all factors, and which is helpful to understand the cure technique for XT–DDS system. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3483–3489, 2006     

测井资料在井壁稳定性研究中的应用

井壁稳定性问题是石油钻井工业面临的一个重大课题。利用测井资料研究井壁稳定性是一种有效的方法。文章利用声波、密度测井资料计算了岩石力学参数、岩石强度参数，在此基础上进行了地应力计算、进而确定了地层破裂压力和坍塌压力，预测了安全钻井液密度范围，为钻井设计提供参考，并可指导安全钻井。通过新疆X 201井安全钻井液密度窗口的测井预测值与实钻钻井液密度对比分析，证明利用测井资料评价井壁稳定性的可行性和准确性，具有工程应用价值。