Cycloaddition reactions of some analogs of the acridizinium ion

The 1-aryl-2-imidazo[1,2-b]isoquinolin-4-ium system ( 3 and 4 ), prepared by the action of aniline, or a suitable aniline derivative upon 2-phenacyl-3-chloroisoquinolinium bromide undergoes cycloaddition reactions only with the more nucleophilic alkenes such as cyclopentadiene or 9-vinylcarbazole. The pyrazino[1,2-b]isoquinolin-5-ium-2-oxide ( 8–10 ) system reacts with nucleophilic alkenes more readily than does the acridizinium system 1. For both systems the cycloaddition appears to occur across the meso position of the central ring.     

Exploring the physical,chemical and thermal characteristics of a new potentially insensitive high explosive RX-55-AE-5

Current work at Lawrence Livermore National Laboratory (LLNL) includes both understanding properties of old explosives and measuring properties of new ones. The necessity to know and understand the properties of energetic materials is driven by the need to improve performance and enhance stability to various stimuli, such as thermal, friction and impact insult. This paper will concentrate on the physical properties of RX-55-AE-5, which is formulated from heterocyclic explosive, 2,6-diamino-3,5-dinitropyrazine-1-oxide, LLM-105, and 2.5% Viton A. Differential scanning calorimetry (DSC) was used to measure a specific heat capacity, C _p, of≈0.950 J g⁻¹ °C⁻¹, and a thermal conductivity, κ, of≈0.475 W m⁻¹ °C⁻¹. The LLNL kinetics modeling code Kinetics05 and the Advanced Kinetics and Technology Solutions (AKTS) code thermokinetics were both used to calculate Arrhenius kinetics for decomposition of LLM-105. Both obtained an activation energy barrier E≈180 kJ mol⁻¹ for mass loss in an open pan. Thermal mechanical analysis, TMA, was used to measure the coefficient of thermal expansion (CTE). The CTE for this formulation was calculated to be ≈61 μm m⁻¹ °C⁻¹. Impact, spark, friction are also reported.     

含有脂肪族侧链的聚醚醚酮的合成、表征及结构与性能关系

以苯酚和含有不同链长的长链脂肪酮作为原料, 制备了与双酚A结构相似的双酚单体, 并与4, 4'-二氟二苯酮共聚, 合成了几种含有不同长度脂肪族侧链结构的聚醚醚酮类(PEEKs)聚合物. 利用元素分析和核磁共振氢谱(1H NMR)对所合成的双酚单体进行了表征, 并用红外光谱(FTIR)\, 示差量热扫描仪(DSC)、热失重分析仪(TGA)和电子拉力机对所合成的聚合物结构和性能的关系进行了研究.     

同位素稀释超高效液相色谱-串联质谱法测定人血清中孕酮

建立了超高效液相色谱-串联质谱(UPLC-MS/MS)测定人血清中孕酮的分析方法。血清样品经乙酸乙酯、正己烷液液萃取(LLE)后,采用Acquity UPLC BEH C_(18)色谱柱(2.1 mm×100 mm,1.7μm)进行梯度分离,色谱运行时间为5 min,采用电喷雾(ESI)正离子电离模式和多反应监测(MRM)扫描模式,同位素内标法定量。考察了两步萃取法对孕酮的提取效果,不同流动相的分离效果以及样品稳定性,结果表明以甲醇-0.1%氨水溶液为流动相时分离效果较好。优化条件下,孕酮在10～10 000pg/mL范围内线性关系良好(r~2=0.999 8),方法检出限和定量下限分别为5、10 pg/mL;平均加标回收率为91.5%～106%,日内相对标准偏差(RSD)为1.2%～8.2%,日间RSD为4.1%～9.1%。采用该方法对30个真实血清样品进行测定,孕酮质量浓度为0.050 2～1.363 5 ng/mL,均在正常生理范围内。该方法灵敏度高、准确可靠,可用于临床血清样品中孕酮生理水平的检测。     

Infrared investigation of the reactions of rhodiumcarbonyl halides and carbon monoxide at elevated pressures

Infrared spectral results at elevated carbon monoxide pressures suggest that rhodiumdicarbonyl halides and carbon monoxide exist in an equilibrium with the corresponding rhodiumtricarbonyl halides.     

Dynamics of water confined in single- and double-wall carbon nanotubes

Using high-resolution quasielastic neutron scattering, we investigated the temperature dependence of single-particle dynamics of water confined in single- and double-wall carbon nanotubes with the inner diameters of 14+/-1 and 16+/-3 A, respectively. The temperature dependence of the alpha relaxation time for water in the 14 A nanotubes measured on cooling down from 260 to 190 K exhibits a crossover at 218 K from a Vogel-Fulcher-Tammann law behavior to an Arrhenius law behavior, indicating a fragile-to-strong dynamic transition in the confined water. This transition may be associated with a structural transition from a high-temperature, low-density (<1.02 gcm(3)) liquid to a low-temperature, high-density (>1.14 gcm(3)) liquid found in molecular dynamics simulation at about 200 K. However, no such dynamic transition in the investigated temperature range of 240-195 K was detected for water in the 16 A nanotubes. In the latter case, the dynamics of water simply follows a Vogel-Fulcher-Tammann law. This suggests that the fragile-to-strong crossover for water in the 16 A nanotubes may be shifted to a lower temperature.     

On the origin of the redshift of the OH stretch in Ice Ih: evidence from the momentum distribution of the protons and the infrared spectral density

Recent measurements of the momentum distribution in water and ice have shown that the proton is in a considerably softer potential in ice Ih than in water or the free monomer. This is broadly consistent with the large red shift observed in the vibrational spectrum. We show that existing water models, which treat the intramolecular potential as unchanged by the hydrogen bonding are unable to reproduce the momentum distribution. In addition, even if they can substantially explain the red shift they are unable to explain the large increase in intensity observed in the infrared spectrum in going from the monomer to ice Ih. We show that the inclusion of a bond dipole derivative term is essential to explain the observed intensities in the infrared spectrum. Though this term is partially responsible for the softening of the effective potential of the proton we show that best agreement with the observed momentum distribution requires a further softening of the harmonic component of the intramolecular potential. We introduce an efficient normal-mode molecular dynamics algorithm for calculating the momentum distribution with path-integrals.     

产学研合作创新方式下政府补贴策略选择

创新补贴策略是政府鼓励企业创新的一种常见政策,考虑到企业内在的吸收能力与外部不同政府补贴策略方式的存在,本文以产学研合作创新方式为基础,通过建立三阶段博弈模型,利用模型解析与仿真分析讨论吸收能力与创新投入分配比例系数对政府补贴策略选择的影响。研究结果表明:无论政府采取哪一种补贴方式,均可以有效激励企业加大创新投入规模,并且企业的吸收能力与R&D投入、产量及社会福利均呈正相关关系;但是,吸收能力对利润及政府补贴的影响受限于补贴方式和企业的创新投入分配比例系数;此外,在创新产品补贴下,创新难度系数对政府补贴额度的影响并不明显,而创新产品补贴总体优于创新投入补贴。