Synthesis of large diamond crystals containing high-nitrogen concentration at high pressure and high temperature using Ni-based solvent by temperature gradient method

This paper reprots that with Ni-based catalyst/solvent and with a dopant of NaN 3,large green single crystal diamonds with perfect shape are successfully synthesized by temperature gradient method under high pressure and high temperature in a China-type cubic anvil high-pressure apparatus (SPD-6×1200),and the highest nitrogen concentration reaches approximately 1214-1257 ppm calculated by infrared absorption spectra.The synthesis conditions are about 5.5 GPa and 1240-1300 C.The growth behaviour of diamond with high-nitrogen concentration is investigated in detail.The results show that,with increasing the content of NaN 3 added in synthesis system,the width of synthesis temperature region for growth high-quality diamonds becomes narrower,and the morphology of diamond crystal is changed from cube-octahedral to octahedral at same temperature and pressure,the crystal growth rate is slowed down,nevertheless,the nitrogen concentration doped in synthetic diamond increases.     

MOFs基催化剂活化过硫酸盐在废水处理中的研究进展北大核心CSCD

金属有机框架(MOFs)材料作为一种新兴的多功能材料,因其高的比表面积、可调的孔隙结构、优异的热稳定性和化学稳定性等优势,在催化活化高级氧化水处理领域引起越来越多关注。本综述聚焦于近5年MOFs基催化剂活化过硫酸盐在水处理领域的研究进展。汇总了过硫酸盐活化领域中的各类MOFs基催化剂;介绍了过硫酸盐活化中MOFs基催化剂的常用合成方法;归纳了MOFs基催化剂在活化过硫酸盐过程中的氧化机制;总结了MOFs基催化剂的常见改性方法;最后,对MOFs基催化剂活化过硫酸盐未来研究方向提出了几点建议。有助于加深对MOFs基催化剂活化过硫酸盐降解有机污染物的认识,为开发基于过硫酸盐活化的MOFs基新型非均相催化剂提供理论参考。     

PMP柱前衍生反相高效液相色谱—紫外检测法结合离子色谱—脉冲安倍法测定不同产地泽泻多糖的单糖组成

本文建立了1-苯基-3-甲基-5-吡唑啉酮(PMP)柱前衍生高效液相色谱-紫外检测法结合离子色谱-脉冲安倍法测定泽泻中10种单糖含量的测定方法,并比较了不同产地泽泻多糖中的单糖组成差异。经测定泽泻多糖中含有葡萄糖、半乳糖、半乳糖醛酸和阿拉伯糖,其中葡萄糖含量最高,说明泽泻多糖是以葡聚糖为主的杂多糖。不同产地泽泻多糖中葡萄糖、半乳糖、半乳糖醛酸含量差异显著(P<0.05),葡萄糖含量由高到低依次为广泽泻(166.940～264.724 mg/g)、川泽泻(82.647～155.019 mg/g)和建泽泻(51.148～97.746 mg/g);广泽泻多糖中半乳糖含量(3.511～3.840 mg/g)显著高于川泽泻(1.193～1.797 mg/g,P<0.01)和建泽泻(低于定量限);仅有广泽泻中半乳糖醛酸含量(1.342～1.823 mg/g)高于方法定量限。广泽泻中葡萄糖、半乳糖、半乳糖醛酸摩尔比为60.13∶1∶0.40,川泽泻中葡萄糖、半乳糖摩尔比为1545.05∶1,建泽泻多糖中几乎都是葡萄糖,葡萄糖占比在上述产地多糖中依次增加,三种单糖的杂合程度依次减弱。研究结...     

古代铜矿冶炼过程中稀土元素的变化研究

主要研究稀土元素在铜矿冶炼过程中的变化规律及其在冶金考古中的潜在应用。实验采用电感藕合等离子体发射光谱仪(ICP-AES)测试了湖北铜绿山、宁夏照壁山、山西中条山和内蒙古林西大井古代矿冶遗址的铜矿石，炼渣和铜锭的稀土元素含量，通过对其稀土总量和稀土配分模式的对比研究，探讨了稀土元素在古代铜矿冶炼过程中的化学行为。结果发现稀土元素在铜矿冶炼过程主要富集在炼渣中，金属铜中的稀土元素含量很低。因此，要想根据青铜器中的稀土元素特征示踪铜料来源，是很难实现的。通过对比各矿冶遗址的铜矿石、炼渣和铜锭的稀土配分曲线，发现炼渣的稀土配分曲线为判断古代所使用的冶炼技术及铜矿石的输出路线提供了可能。     

Microcalorimetric Evaluation of the Effect of Kanamycin： An Analysis Based on the Median-Effect Principle

A study of the effect of drug, kanamycin, on the growth metabolism of recombinant Escherichia coli B 1 was carded out by microcalorimeter monitoring of the metabolic activity of treated cells. Power-time curves of growing recombinant Escherichia coli cell suspensions, treated with different kanamycin doses, were recorded. The extent of the effect was evaluated by changes in the slopes of the microcalorimetric curves and the kinetics of the drug action was interpreted from the time at which these changes reached their maximum values and maintained their maximum values. Experimental dose-effect relationships conform to the median-effect principle of the mass-action law： fa/（1-fa）=（D/D50）^m. A plot of y=lg[（fa）^1-1]^-1 versus x=lg D gives the slope m, D50 and R∞. The experimental results revealed that high concentration of kanamycin had an inhibitory effect on the growth of recombinant Escherichia coli B 1 in the lg phase, and had a promoting effect in the stationary period. Moreover, it was demonstrated that microcalorimetry was a reliable method for the detection of modulatory effects in biology.     

含氮杂环多芳基咪唑衍生物的合成及其光物理性能

以冰醋酸为溶剂和催化剂,苯偶酰/9,10-菲醌、3-吲哚甲醛/3-咔唑甲醛及醋酸铵经"一锅"反应高效合成了系列含吲哚或咔唑结构单元的多取代咪唑衍生物.考察了反应物配比、溶剂的选择和用量及温度等因素对反应的影响,研究了所合成化合物的光物理性能;筛选出对p H值敏感且结构独特的两个化合物作为p H荧光探针,检测在其作用下MCF-7细胞在不同p H值环境中的荧光成像,结果表明探针2-(9-苄基-9H-咔唑-3-基)-4,5-二苯基-1H-咪唑(2d)和2-(9-苄基-9H-咔唑-3-基)-1H-菲并[9,10-d]咪唑(4)都可用作检测活细胞内p H变化的p H荧光探针.     

Study on the Interaction of Colloidal Gold with Taq DNA Polymerase

The interaction of colloidal gold with Taq DNA polymerase （Taq） was investigated in this study. Taq-gold conjugate was formed by adding the enzyme to the colloidal gold solution, as evidenced by UV-Vis spectroscopy, X-ray photoelectron spectroscopy, and photon cross correlation spectroscopy measurements. The conjugate was further characterized by transmission electron microscopy. It was found that the Taq-gold conjugate particles were still spherical and well-dispersed. The influence of gold nanoparticles on the bioactivity of Taq was studied by analyzing the yield of the polymerase chain reaction amplification. Results indicated that the enzymatic activity of Taq decreased after interaction with the colloidal gold.     

He-N2碰撞体系散射截面的理论研究

本文运用量子化学从头计算MP2方法6-311 G(3df,2p)基组,计算了He-N2相互作用的势能,拟合出He原子与N2分子相互作用的各向异性势函数,其势函数参数:势能球平均势阱位置、势阱深度、势能零点位置与通过散射实验数据分析的ESMSV(Exponential-Spline-Morse-Spline-Van der waals)势比较吻合.然后,用公认精确度高的密耦方法计算了He原子与N2分子碰撞体系的总微分截面、弹性微分截面、转动激发的非弹性微分截面和积分截面,计算结果与实验数据符合得较好.     

无线接入技术浅析

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