The Resonance Neutrons in Activation Analysis Part 1: Theory

A great majority of studies in the field of neutron activation analysis is concerned with the question of how to distinguish the activity of the radionuclide arising from the determined element from the activity of other radionuclides in the sample following activation.     

热声驱动器谐振频率影响因素分析

分析了结构参数、操作参数以及工质等因素对热声驱动器谐振频率的影响 ,并结合驻波型热声驱动器 ,给出了相应的计算结果和实验数据。     

Quantitavive Proton Magnetic Resonance Analysis of Ranitidine in Solid Dosage Forms

A rapid and specific proton magnetic resonance (PMR) spectroscopic method was developed for determining ranitidine hydrochloride in tablets. 2-Choloroacetophenon was used as the internal standard and DMSO-d₆ served as the PMR solvent. The concentration of drug per unit dose was calculated from the integration values for the resonance signals of ranitidine hydrochloride at 4.32 δ ppm and int. st. at 5.19 δ ppm. The method using commercial products gave comparable results to those obtained by the methods of UV spectroscopy and USP XXIII.     

Quantitative Proton Magnetic Resonance Analysis of Primidone in Solid Dosage Forms

A rapid and specific proton magnetic resonance (PMR) spectroscopic method was developed for determining primidone in tablets. Maleic acid was used as the internal standart and DMSO-d₆ served as the PMR solvent.     

定量核磁共振氢谱测定新药替格瑞洛

本文建立了基于核磁共振氢谱（¹H NMR）测定新药替格瑞洛绝对含量的方法.采用Bruker Avance 300型NMR谱仪,以磺胺多辛为内标;以替格瑞洛中质子信号δ_H 7.14（2H,m）和δ_H 7.04（1H,s）,磺胺多辛质子信号δ_H 8.04（1H,s）、δ_H 7.73（2H,d）和δ_H 6.54（2H,d）作为定量峰;以氘代甲醇（CD₃OD）为溶剂进行测定.测定条件为：探头温度为308 K,谱宽为3 511.5 Hz,中心频率为1 470.6 Hz,脉冲翻转角为θ=30°,延迟时间为10 s,采样次数为16,线宽因子为0.3 Hz.在此实验条件下,替格瑞洛样品与内标磺胺多辛的定量峰分离良好,实验结果精密度较高、重复性较好、线性范围较宽,其线性拟合方程为：Y=1.053X-0.081（r=0.996,n=5）.最终测得样品中替格瑞洛含量为99.4%,相对标准偏差（RSD）为0.20%.该方法简便、准确、快速,适用于替格瑞洛样品的绝对含量测定.     

发动机喷流对火箭气动特性影响

开展了考虑底部发动机喷流影响的火箭气动特性CFD仿真设计,比较了有/无喷流时火箭附近流场结构、表面压力分布、整体气动力/力矩特性在亚/超声速段的差异,结果显示,发动机喷流对火箭亚声速段的轴向力、法向力和俯仰力矩特性均有较为显著的影响,且有减小尾部空气舵气动控制力矩的影响,而超声速段的影响仅限于轴向力。该仿真结果与飞行试验气动辨识结果较为一致。基于仿真分析结果,可建立一种折中考虑喷流影响的气动特性设计方法,供火箭精细化气动特性设计参考使用。      

Study of the Proton Magnetic Resonance of Methoxy-Tamoxifen Towards Ortho-Substitution

The objective of the work was to study the proton magnetic resonance of derivatives of methoxytamoxifen towards ortho substitution of a trialkylstannyl-moiety and iodine. Since Iodo-methoxytamoxifen was specially needed for further biological studies in the detection and characterisation of breast tumors, it was necessary to be certain of the position of substitution (i.e. ortho to the amino ether).     

Determination of Diethylcarbamazine Citrate in Tablets by Proton Magnetic Resonance

A simple, specific and accurate proton magnetic resonance (PMR) procedure has been developed for the quantitative determination of diethylcarbamazine in standard mixtures and tablets. The average recovery of the pure drug in standard mixtures with maleic acid as an internal standard was 100.03 ± 0.11% w/w. Reproducible results were obtained when the drug was determined in its tablet dosage form.     

Viscosity Correlations with Nuclear (Proton) Magnetic Resonance Relaxation in Oil Disperse Systems

Using nuclear (proton) magnetic resonance relaxometry (NMRR) was studied oil disperse systems. Dependences of NMR–relaxation parameters—spin–lattice T_1i, spin–spin T_2i relaxation times, proton populations P_1i and P_2i, and petrophysical correlations were received for light and heavy oils. Experimental results are interpreted on the base of structure-dynamical ordering of oil molecules with structure unit formation.     

Proton Resonance Assignments in Oligosaccharides Containing Multiple Monosaccharide Residues of the Same Type

A technique is described for assisting the resonance assignment process in oligosaccharide proton NMR spectra, where multiple residues of the same type generate extreme resonance overlap in the spectrum. The approach involves the modification of a conventional HOHAHA experiment with constant-time acquisition in t₁, which effectively proton decouples the C-1 protons of residues whose resonances overlap, thus affording a significant increase in effective resolution in that dimension. For a sufficiently long spin-lock time, complete one-dimensional subspectra are obtained essentially free of cross talk from adjacent resonances. Further simplification of the assignment process is illustrated by incorporation of the constant-time modification into a three-dimensional HOHAHA-HOHAHA experiment.     

基于ＳＣＰＩ的运载火箭遥测系统自动测试平台设计

针对目前火箭遥测系统专属测试设备操作复杂、通用性差等特点,提出一种基于SCPI指令的虚拟仪器智能测试方案,利用SCPI指令完成程序对智能设备的输出控制,结合TCP/IP通信技术、数据库访问技术以及在LabVIEW程序中完成Excel动态存储技术等,实现了火箭遥测系统电性能自动测试、闭环测试、在线监测等功能,测试结果表明,测试平台极大地提高了系统测试效率,测试数据可靠性好,可满足运载火箭遥测系统电性能测试工作,具有较好的推广价值。     

Hydrogen Bonding Study of Quinoline and Coal-Derived Asphaltene Components with o-Phenylphenol by Proton Magnetic Resonance

Abstract

Proton magnetic resonance (PMR) studies are reported of hydrogen bonding between the OH proton of o-phenylphenol (OPP) and the nitrogen electron donor of quinoline (Qu). Data are also reported on the hydrogen bonding of a coal-derived asphaltene and its acid and base components with OPP. Determination was made of the equilibrium constants of the 1:1 complex between OPP and Qu at 39, 32, 1, and ?18°C from the PMR studies. Qualitative results are reported for the interaction between the base fraction of asphaltene and OPP at 32, 1, and ?26°C.     

Further Development of Automatic Activation Analysis System (AAAS) with Fast Neutrons

Improvement of results of activation analysis has been achieved by using a device for simultaneous rotation of the sample around tow axes: one parallel and the other perpendicular to the target during the irradiation. A change of the construction of the container resulted in the increase of its volume and a decrease in the mean sample-to-target distance. The distribution of the neutron flux along the axis of the container during the irradiation has been measured. An arrangement for automatic loading and unloading of sample is also described.     

远程激光诱导击穿光谱技术分析岩石元素成分

远程激光诱导击穿光谱技术是一种利用脉冲激光和聚焦光路对远距离目标烧蚀击穿,获取目标等离子体光谱,定性或定量分析物质元素组成的光谱探测技术。设计并搭建了一套远程激光诱导击穿光谱系统。该系统结合卡式望远镜光学结构,实现探测2～10 m距离的目标、并可自动变焦。基于该系统提出一种远程探测岩石主要元素含量方法。通过对比实验,研究了脉冲能量、采集延时、积分时间、探测点累计探测次数对光谱信号的影响,确定了岩石谱线获得的最佳条件。选择48块岩石标本和6种常见国标岩石样品(页岩、花岗岩、安山岩、玄武岩、片麻岩、伟晶岩)进行LIBS实验。以原子光谱数据库为参考,根据岩石的主要元素提取特征谱线(SiⅠ390.55 nm,AlⅠ394.40 nm,AlⅠ396.15 nm,CaⅡ396.85 nm,FeⅠ404. 60 nm,SiⅠ500.60 nm,MgⅠ518.36 nm,NaⅠ589.59 nm)。利用偏最小二乘算法(PLS)建立岩石成分定量分析模型,将48块岩石标本作为训练集进行求解,并用六种国标岩石对模型进行检测,预测岩石Si和Al元素含量,平均误差分别为9.4%和9.6%。     

Prediction of Wall Heat Fluxes in a Rocket Engine with Conjugate Heat Transfer Based on Large-Eddy Simulation

Although a lot of research and development has been done to understand and master the major physics involved in cryogenic rocket engines (combustion, feeding systems, heat transfer, stability, efficiency, etc.), the injection system and wall heat transfer remain critical issues due to complex physics, leading to atomization in the subcritical regime and the interactions of hot gases with walls. In such regimes, the fuel is usually injected through a coaxial annulus and triggers the atomization of the central liquid oxidizer jet. This type of injector is often referred to as air-assisted, or coaxial shear, injector, and has been extensively studied experimentally. Including such injection in numerical simulations requires specific models as simulating the atomization process is still out of reach in practical industrial systems. The effect of the injection model on the flame stabilization process and thus on wall heat fluxes is of critical importance when it comes to the design of wall-cooling systems. Indeed, maximizing the heat flux extracted from the chamber can lead to serious gain for the cooling and feeding systems for expander-type feeding cycles where the thermal energy absorbed by the coolant is converted into kinetic energy to drive the turbo-pumps of the feeding system. The methodology proposed in this work to numerically predict the flame topology and associated heat fluxes is based on state-of-the-art methods for turbulent reactive flow field predictions for rocket engines, including liquid injection, combustion model, and wall treatment. For this purpose, high-fidelity Large Eddy Simulation Conjugate Heat Transfer, along with a reduced kinetic mechanism for the prediction of H2/O2 chemistry, liquid injection model LOx sprays, and the use of a specific wall modeling to correctly predict heat flux for large temperature ratio between the bulk flow and the chamber walls, is used. A smooth and a longitudinally ribbed combustor configuration from JAXA are simulated. The coupling strategy ensures a rapid convergence for a limited additional cost compared to a fluid-only simulation, and the wall heat fluxes display a healthy trend compared to the experimental measurements. An increase of heat transfer coherent with the literature is observed when walls are equipped with ribs, compared to smooth walls. The heat transfer enhancement of the ribbed configuration with respect to the smooth walls is coherent with results from the literature, with an increase of around +80% of wall heat flux extracted for the same chamber diameter.     

脉冲微放电发射光谱用于合金样品元素分析

利用大气压脉冲微放电剥蚀源对铝合金进行光谱分析。该针板结构微放电装置具有价格低廉、操作便捷、分析快速等特点。脉冲放电能瞬间注入极大的放电能量,不致使样品融化,进而保证放电的稳定性。在几微秒的时间内,对钨针电极施加近-4 000 V的高压,电极间迅速形成放电通道,针尖和样品之间形成高达20 A的电流,造成对样品的剥蚀,并对被剥蚀的粒子进行激发。单次放电脉冲注入能量约为8.5 mJ,能量以电流的形式传递于放电电极。剥蚀形貌图表明放电微等离子体局域在电极间隙,针尖轴向上的能量传递和电流密度远高于离轴区域。为了深入研究剥蚀机制和物理性质,对等离子体源的电学特性进行了讨论。通过精确的时序拍摄技术观测了等离子体的演化过程,从ICCD相机的快速成像结果可以看到等离子体源寿命与脉冲高压放电源的脉宽相当,发光强度与放电电流变化趋势相吻合。与光谱分析装置相连接,脉冲微放电剥蚀源可有效激发合金样品中的铝、镁、锰、铜等元素原子谱线。对放电过程等离子体光谱特性进行考察,利用玻尔兹曼斜线法和Stark展宽法计算等离子体电子温度和电子数密度,分别得到过程中等离子体电子激发温度约6 700 K,等离子体电子数密度约1017 cm-3量级,并验证了放电处于局域热平衡状态。探究其定量分析性能,结果表明该脉冲微放电等离子体直接作为一种光谱分析源可实现对铝合金样品快速定量分析。     

用于固体火箭羽焰真温测量的宽量程多光谱高温计

现有的多光谱高温计的测量下限均大于1 173 K(900 ℃),不适用于新型火箭羽焰真温测量范围的要求(900~2 700 K)。为了解决现有的多光谱高温计无法测量1 173 K以下羽焰真温的问题,研制了用于固体火箭发动机羽焰真温测量的宽量程多光谱高温计。该多光谱高温计采用了并联光电探测器阵列相邻像元的方法,并且创建了基于对数函数的900~1 173 K温区的温度标定方法,从而拓宽了高温计的温度测量范围。针对某型号固体火箭发动机羽焰的三个目标点进行了现场测量,实验结果验证了该高温计的有效性。     

Neutrons at the boundary of magnetic media

The behavior of a neutron as a quantum-mechanical top at the boundary of two magnetically noncollinear media is analyzed. Attention is paid to such phenomena as splitting of reflected and refracted beams, total reflection forwards, cross interference, polarization and depolarization effects. The exact formulae are obtained for the reflectivity and transmittance of neutrons with the spin precessing in the guide field. In a weak guide field approximation, they are simplified and generalized for a stratified, collinearly magnetized, medium and for oscillating guide fields. It is pointed out that reflection of neutrons can be used to study the spin superposition and to carry out the Wigner experiment on the result of a quantum mechanic measurement. Neutron spin turners including flippers can be made with mirrors on the basis of magnetically anisotropic thin films.     

Troubles with the Proton rms-Radius

Due to the peculiar shape of the proton charge density ??(r) the value of the rms-radius r _rms determined from electron scattering data depends strongly on the density ??(r) at large radii, which is not fixed by scattering data. Supplementing the data with the large-r shape of ??(r) resulting from the Fock components (n?+???, . . .) dominating the large-r behavior produces a more reliable value. This radius agrees with the one we previously extracted, but disagrees with the one recently obtained from muonic Hydrogen. The origin of the discrepancy is not understood.