Shock Melting Temperature of Initially Porous Iron and Indication for Melting Curve of Iron at High Pressures

The melting curve of iron is crucial for modelling of the earth‘s internal heat structures and to understand melting of solids at high pressures. However, the measured melting temperatures of iron at high pressures are disparate so far. We measured the shocked interface (porous iron/sapphire window) temperatures of a kind of porous iron.By using a model for shock temperature measurement [High Pressures Res. 2 (1990) 159] and the previous results of sound velocity measurements [Chin. Phys. Lett. 18 (2001) 852], we determine the melting temperatures of iron at shock compression high pressures of 145 and 171 GPa. They are consistent with the results reported by other shock compression experiments. Based on the possible different melting mechanisms of iron in diamond anvil cell and in shock compression, the corrected melting temperatures of iron at high pressures become more consistent.     

光学相控阵技术研究进展与发展趋势

光学相控阵技术具有响应速度快、系统紧凑、功能多样和控制灵活等优点,在众多科学技术领域得到了广泛的应用。在近50年来的光学相控阵研究与应用中,涌现出了众多卓越的成果。为了对光学相控阵领域的发展进行梳理,简要回顾了光学相控阵技术的历史,并论述了光学相控阵技术的基本原理。从光束发射与接收等不同应用场景的角度,结合笔者的思考,深入介绍了光学相控阵在高品质的光源技术、激光相干合成技术、光束扫描技术、大气链路畸变控制技术以及合成孔径探测与成像技术多个领域的发展现状,并最后对光学相控阵技术的瓶颈与未来的发展研究趋势进行了评述。     

A Direct Comparison between Static and Dynamic Melting Temperature Determinations below 100 GPa

A preliminary experiment of sound velocity measurements for porous iron with initial average density of 6.275 g/cm^3 has been performed at pressures below 100 CPa, in order to clarify a long-standing problem that the static melting temperature Tin, mostly below 100CPa due to its technical limitations, is notably lower than the extrapolated melting data inferred from the shock wave experiments made above 200 CPa, for the sake of making a direct comparison between the experimental static and dynamic melting temperatures in the same pressure region. With the lately proposed Hugoniot sound velocity data analysis technique [Chin. Phys. Left. 22 (2005) 863], the results deduced from this Hugoniot sound velocity measurement is Tm = 3200 K at 87 CPa and Tm = 3080 K at 80 GPa, which are in good agreement with the two latest static data of Tm = 3510 K at 105 GPa and Tm = 2750 K at 58 GPa, which utilized modern improved double-side laser heating and in situ accurate x-ray diffraction techniques in experiments. It can be concluded that consensus Tm data would be obtained from static and shock wave experiments in the case that the recently improved techniques are adopted in investigations.     

复杂矿样中锡钨的联合测定

砷、锑、铜、氟等对锡的碘量法和钨的硫氰酸盐比色法均有干扰,当分析上述元素含量较高的矿样时,需要预先分离。为此进行加硫酸铵焙烧除砷的试验,並用含磷酸钠或EDTA而适当提高碱度的浸出液浸出以减少铁、钙、镁对锡、钨的吸附和有利于锡转化为锡酸钠于溶液中。试样经焙烧后砷、锑、氟等被驱除,再碱熔水浸则使铁、钙、镁、钛、锰、锆、钡、银、金、铋、镉、钴、汞、镍、钍、铌、钽和稀土元素,以及绝大部份铜进入沉淀,只有铝、锌、钼、铬     

Evidence for a Possible E（5） Symmetry in ^130Xe

By analysing the energy spectrum and E2 transition branching ratios,we show that the E(5) symmetry predictions agree well with the experimental data of nucleus 130Xe,Compared the calculated results with those within the framework of the interacting boson model.It is found that the nucleus 130Xe is definitely a nucleus in the transitional region from U(5) to O(6) symmetry,130Xe is then another empirical evidence of the nucleus with E(5) symmetry.     

MCM-41担载的镍钼硫化物上二苯并噻吩的加氢脱硫反应动力学

 采用高压滴流床反应器研究了在WHSV＝30~90 h-1,p＝5.0 MPa和θ＝280~340 ℃的条件下,二苯并噻吩(DBT)在不同Ni含量的Ni-Mo/MCM-41催化剂样品上的加氢脱硫(HDS)反应动力学. 应用拟1级活塞流模型计算了该系列催化剂上的HDS反应的表观反应速率常数以及加氢反应路径和氢解反应路径的反应速率常数. 结果表明,加氢反应路径的速率常数和氢解反应路径的速率常数在同一个数量级上,说明在Ni-Mo/MCM-41上进行DBT的HDS反应时, 这两个平行的反应路径是并重的. 随着催化剂中Ni/Mo原子比的增大,两个反应路径的速率常数均增大,并在Ni/Mo原子比为0.75时达到最大值. 当Ni/Mo原子比增大到1.0时,两个反应路径的速率常数均大幅下降. 根据Arrhenius方程求得了DBT在Ni-Mo/MCM-41上进行HDS反应的表观活化能. 结果表明,催化剂的活性与表观活化能存在明显的相关关系,活化能越低,活性越高.     

聚合物串联耦合双环电光开关的优化

利用耦合模理论、电光调制理论和微环谐振理论,提出一个聚合物串联耦合双环电光开关器件模型,在1.55 μm谐振波长下对该器件进行了模拟和优化.结果为：微环波导芯截面尺寸为1.6×1.6 μm2,波导芯与电极间的限制层厚度为1.6 μm,电极厚度为0.15 μm,微环半径为15.2 μm,微环与信道间的耦合间距为0.14 μm,微环与微环间的耦合间距为0.6 μm,输出光谱的3 dB带宽约为0.06 nm,开关电压约为6 V左右,插入损耗约为2.2 dB,串扰约为－20 dB.所设计的双环电光开关较单环型电光开关不仅输出光谱更加平坦陡峭,非谐振光更弱,而且开关电压更低.     

组装在贵金属基底上的金纳米粒子对CO的电化学催化氧化

研究了组装在Au, Pt电极表面的金纳米粒子对CO的电化学催化氧化行为, 首次在实验上观察到较大粒径金纳米粒子(粒径＞10 nm)对CO的电催化氧化活性. 考察了金粒子表面金氧化物对粒子电催化活性的影响, 发现表面金氧化物的形成是金纳米粒子对CO具有电催化氧化活性的前提. 对于相同粒径的金纳米粒子, 随着粒子表面金氧化物量的增加,催化活性增大.     

稀土脯氨酸配合物[RE2(L-Pro)6(H2O)4](ClO4)6的标准生成焓测定

合成了两种稀土高氯酸盐与L 脯氨酸配合物的晶体.经热重、差热、化学分析及对比有关文献,知其组成是[Pr2(L Pro)6(H2O)4](ClO4)6和[Er2(L Pro)6(H2O)4](ClO4)6,质量分数为99.24％和98.20％.选用RE(NO3)3•6H2O(RE=Pr,Er)、L Pro、NaClO4•H2O和NaNO3作辅助物,使用具有恒温环境的反应热量计,以2 mol•L－1 HCl作溶剂,分别测定了[2RE(NO3)3•6H2O＋6L Pro＋6NaClO4•H2O]和{[RE2(L PrO)6(H2O)4](ClO4)6＋6NaNO3}在298.15 K时的溶解热.设计一热化学循环求得化学反应的反应焓ΔrHm分别是：63.904 kJ•mol－1和91.017 kJ•mol－1,经计算得配合物[RE2(L Pro)6(H2O)4](ClO4)6(s)在298.15 K时的标准生成焓ΔfHm(298.15 K)分别是－6 594.78 kJ•mol－1和－6 532.87 kJ•mol－1.     

QuEChERS-超高效液相色谱-串联质谱测定青贮牧草中23种农药残留

采用改进的QuEchERS前处理方法结合超高效液相色谱串联质谱（UPLC-MS/MS），建立了青贮皇竹草中23种农药残留的检测方法。样品经超纯水浸泡，1%甲酸乙腈提取，无水MgSO4、乙二胺-N-丙基硅烷（PSA）、十八烷基硅烷（C18）和石墨化炭黑（GCB）基质分散净化，Agilent ZORBAX Eclipse Plus C18色谱柱分离，电喷雾串联质谱多反应监测（MRM）模式测定。23种农药在0.5～20μg/L范围内线性关系良好（R2>0.9986），检出限为0.002～0.1μg/kg，定量限为0.005～0.2μg/kg。在0.5, 1, 5μg/kg 3个添加浓度水平下，回收率在76.2%～105.9%，相对标准偏差（RSD）在2.3%～11%。该方法适用于青贮皇竹草中23种农药的定性定量分析。