环Zn上椭圆曲线的群法则及其在Paillier系统中的应用

本文研究了定义在环Zn上椭圆曲线E的有理点集E(Zn)的群的定义法则,以及这类椭圆曲线在密码学上的应用.我们给出了环Zn上椭圆曲线明确的点加公式,使得E(Zn)形成一个交换群,从理论上清晰地解决了以往在该类曲线上某些点相加不能定义的问题.为了在密码学上方便地应用这类椭圆曲线,还给出了在该加法法则下的E(Zn)的群结构....     

紫金洗煤厂絮凝剂自动添加系统的研究

针对紫金洗煤厂煤泥水处理的实际情况,设计了絮凝剂自动添加控制系统。系统根据实时检测到的煤泥水浓度、流量以及溢流水浊度,通过前馈和反馈相结合的方法,自动控制絮凝剂添加量。工业试验表明:使用该系统降低了药耗,稳定了溢流水浊度,改善了循环水质量。     

高效浓密机机理研究

目前,在国内的许多浓密机制造厂都称自己生产的是高效浓密机,实际上有些所谓的高效浓密机除了将进料点下移之外,与普通浓密机没有什么区别。根据对国外引进浓密机的调试经验和对国产浓密机的改造体会,对高效浓密机的设备结构和工作机理进行论述,其中有许多是我们自己的研究成果和对其作用机理的理解。     

烯烃加成法合成烷基酚聚氧乙烯醚磺酸盐

实验以烯烃加成法,经烯丙基化、磺化二步反应合成了烷基酚聚氧乙烯醚磺酸盐.在烯丙基化过程中,分别以十六烷基三甲基溴化铵和聚乙二醇为催化剂,得到产率不同的中间体烯丙基醚;在磺化过程中,以烯烃加成反应,以亚硫酸氢盐-亚硫酸盐为磺化剂,硝酸盐为催化剂,或以添加产物为催化剂,得到产率不同的磺酸盐.讨论了二步反应中使用不同催化剂产...     

手性铜试剂在羰基化合物加成反应中的应用

介绍了有机铜试剂具有价格低廉、毒性小、配位能力好等的优点,总结了有机铜试剂在不饱和羰基化合物的不对称共轭加成反应中的应用,特别是催化不饱和酯、硫酯、砜、醛和酮等α,β-不饱和羰基化合物的不对称共轭加成反应,提出了手性铜试剂催化不对称共轭加成反应在底物选择上仍然具有一定的局限性,该反应的底物主要集中于酮类化合物,而砜类和...     

1,1-二氟-1-氯乙烷合成研究进展

介绍了1,1-二氟-1-氯乙烷(HCFC-142b)的基本性质、用途和合成研究进展,比较了直接氟代法、偏氯乙烯加成氟代法和光氯化法的研究概况和不同方法的优缺点.采用在催化剂存在下,用偏氯乙烯和氟化氢在液相中加成氟化的方法生产HCFC-142b是最具工业前景的合成路线,该工艺路线的关键是氟化催化剂的选择,选择一种助催化剂...     

Er掺杂强韧化Al_2O_3/TiAl复合材料

以Ti、Al、TiO2为起始原料,以Er2O3为掺杂剂,原位热压合成了Er掺杂Al2O3/TiAl复合材料。通过XRD、SEM分析及力学性能测试,研究了不同Er2O3引入量对合成Al2O3/TiAl复合材料微观结构和力学性能的影响。结果表明:复合材料主要由TiAl、Ti3 Al、Al2 O3相和少量Al10 Er6 O24相组成,含Er相主要分布在基体相晶界处;掺杂0.01 mol Er2 O3制得的复合材料,经1250℃保温2 h真空热压烧结后表观断裂韧性达到最大值(10.41 MPa.m1/2),经1300℃保温2 h真空热压烧结后弯曲强度达到最大值(456.06 MPa);当Er2O3掺杂量增加到0.02 mol时,复合材料的弯曲强度和表观断裂韧性均呈减小趋势。微观结构分析表明,掺杂0.01 mol Er2O3的复合材料断口毛糙,颗粒尺寸变小,增强相分布较均匀,表明适量的Er2O3掺杂可细化复合材料晶粒尺寸,提高增强颗粒分布均匀度,起到增强增韧的效果。     

Improvement of the growth of Arthrospira (Spirulina) platensis from Toliara (Madagascar): Effect of agitation, salinity and CO2 addition

Arthrospira (Spirulina) platensis Toliara isolated from alkaline and salt lakes in the south-western area of Madagascar is a potential source of proteins that could efficiently fight against food deficiency in developing countries like Madagascar. Up to now, productivity in this country has been low, so a better understanding of the growth conditions of this species is needed to improve its production. Growth experiments were undertaken in bubble columns at laboratory scale. The influence of agitation of the culture, medium salinity (ranging from 13 to 35 g L⁻¹) and CO₂ addition (ranging from 0 to 2%, v/v) on growth and protein content was examined. Because Arthrospira cells are fragile, a bubble column without additional mixing gave the best growth. Arthrospira (Spirulina) platensis showed higher specific growth rate (μ_max) and protein content for lower salinity. Addition of 1% of CO₂ improved the productivity by near 60%. The feasability of semi-continuous culture was demonstrated and optimal culture conditions led to a mean productivity of 0.22 ± 0.03 g L⁻¹ d⁻¹, a mean specific growth rate of 0.015 ± 0.002 h⁻¹ and a protein content of 53 ± 2% of total dry weight.     

Microstructure and piezoelectric properties of CuO-doped 0.95(K0.5Na0.5)NbO3-0.05Li(Nb0.5Sb0.5)O3 lead-free ceramics

The effects of sintering temperature and the addition of CuO on the microstructure and piezoelectric properties of 0.95(K_0.5Na_0.5)NbO₃-0.05Li(Nb_0.5Sb_0.5)O₃ were investigated. The KNN-5LNS ceramics doped with CuO were well sintered even at 940 °C. A small amount of Cu²⁺ was incorporated into the KNN-5LNS matrix ceramics and XRD patterns suggested that the Cu²⁺ ion could enter the A or B site of the perovskite unit cell and replace the Nb⁵⁺ or Li⁺ simultaneously. The study also showed that the introduction of CuO effectively reduced the sintering temperature and improved the electrical properties of KNN-5LNS. The high piezoelectric properties of d₃₃ = 263 pC/N, k_p = 0.42, Q_m = 143 and tan δ = 0.024 were obtained from the 0.4 mol% CuO doped KNN-5LNS ceramics sintered at 980 °C for 2 h.     

助剂MgO对甲烷二氧化碳重整Co/BaTiO3催化剂催化性能的影响

采用溶胶-凝胶法在Co/BaTiO3催化剂中引入助剂MgO,考察了其对甲烷二氧化碳重整Co/BaTiO3催化剂的催化反应性能的影响,利用X射线衍射仪(XRD)、H2程序升温还原(H2-TPR)对催化剂进行了表征,结果表明,助剂MgO使钴催化剂中的活性Co2O3组分增多,还原性和分散性能较好;在n(CO2)∶n(CH4)为1∶1、气相空速(GHSV)为12 000 h-1、反应温度为700℃的条件下,催化剂Co-MgO/BaTiO3表现出良好的催化性能,且反应初期甲烷转化率可达到94.87%,CO选择性可达85.21%,H2收率可达74.08%。