埼玉県行田市埼玉愛宕山古墳の測量・GPR調査

早稲田大学東アジア都城・シルクロード考古学研究所 デジタル調査概報 第4

单壁碳纳米管分子光谱表征及应用的研究进展

不同结构的单壁碳纳米管（SWCNTs）具有不同的光学性质。着重介绍了单壁碳纳米管的基本光学性质，概述了SWCNTs的吸收光谱、拉曼光谱和荧光光谱3种分子光谱袁征技术及其在SWCNTs分离、传感等方面应用的研究进展。系统分析和比较了3种方法的特点，同时展望了分子光谱在SWCNTs表征方面的应用前景

离子液体催化木质素转化制备丁香醛

木质素的高值转化对于生物质的全组分利用具有重要意义,直接关乎生物炼制产业链的经济可行性。离子液体作为一种新型催化剂,具有较高的可设计性、结构稳定性和热稳定性,可用于木质素催化转化制备具有高附加值的小分子产物以提高木质素的利用效率。以乙醇胺类和胍类离子液体为催化剂,考察了木质素种类与用量、催化剂种类与浓度、反应温度和pH值等因素对丁香醛收率的影响。结果表明:当催化剂为乙醇胺四氟硼酸盐[MEA]BF4,木质素与催化剂用量比为2∶1,固液比1∶150,温度160℃,pH=4.35,反应6 h后丁香醛收率最高,为9.20%。</p

离子液体催化木质素转化制备丁香醛

木质素的高值转化对于生物质的全组分利用具有重要意义,直接关乎生物炼制产业链的经济可行性。离子液体作为一种新型催化剂,具有较高的可设计性、结构稳定性和热稳定性,可用于木质素催化转化制备具有高附加值的小分子产物以提高木质素的利用效率。以乙醇胺类和胍类离子液体为催化剂,考察了木质素种类与用量、催化剂种类与浓度、反应温度和pH值等因素对丁香醛收率的影响。结果表明:当催化剂为乙醇胺四氟硼酸盐MEABF_4,木质素与催化剂用量比为2∶1,固液比1∶150,温度160 ℃,pH=4.35,反应6 h后丁香醛收率最高,为9.20%

A Fast-Response Calorimeter with Dynamic Corrections for Transient Heat Transfer Measurements

Robust fast-response transient calorimeters with novel calorimeter elements have attracted the attention of researchers as new synthetic materials have been developed. This sensor uses diamonds as the calorimeter element, and a platinum film resistance is sputtered on the back to measure the temperature. The surface heat flux is obtained based on the calorimetric principle. The sensor has the advantages of high sensitivity and not being prone to erosion. However, non-ideal conditions, such as heat dissipation from the calorimeter element to the surroundings, can lead to measurement deviation and result in challenges for sensor miniaturization. In this study, a novel transient calorimeter (NTC) with two different sizes was developed using air or epoxy as the back-filling material. Numerical simulations were conducted to explain the complex heat exchange between the calorimeter element and its surroundings, which showed that it deviated from the assumption of an ideal calorimeter sensor. Accordingly, a dynamic correction method was proposed to compensate for the energy loss from the backside of the calorimeter element. The numerical results showed that the dynamic correction method significantly improved the measurement deviation, and the relative error was within 2.3% if the test time was smaller than 12 ms in the simulated cases. Detonation shock tunnel experiments confirmed the results of the dynamic correction method and demonstrated a practical method to obtain the dynamic correction coefficient. The accuracy and feasibility of the dynamic correction method were verified in a single detonation shock tunnel and under shock tube conditions. The NTC calorimeter exhibited good repeatability in all experiments

Coaxial Thermocouples for Heat Transfer Measurements in Long-Duration High Enthalpy Flows

Coaxial thermocouples have the advantages of fast response and good durability. They are widely used for heat transfer measurements in transient facilities, and researchers have also considered their use for long-duration heat transfer measurements. However, the model thickness, transverse heat transfer, and changes in the physical parameters of the materials with increasing temperature influence the accuracy of heat transfer measurements. A numerical analysis of coaxial thermocouples is conducted to determine the above influences on the measurement deviation. The minimum deviation is obtained if the thermal effusivity of chromel that changes with the surface temperature is used to derive the heat flux from the surface temperature. The deviation of the heat flux is less than 5.5% when the Fourier number is smaller than 0.255 and 10% when the Fourier number is smaller than 0.520. The results provide guidance for the design of test models and coaxial thermocouples in long-duration heat transfer measurements. The numerical calculation results are verified by a laser radiation heating experiment, and heat transfer measurements using coaxial thermocouples in an arc tunnel with a test time of several seconds are performed