Effect of Thermal Shock Process in Accelerated Environment Spectrum on the Fatigue Life of 7B04-T6 Aluminum Alloy

The effect of thermal shock, in an accelerated-corrosion environment spectrum, on the fatigue and corrosion behavior of 7B04-T6 aluminum alloy, was determined. The environment spectrum consists of two modules, namely： salt-spray corrosion and thermal shock. The effect of thermal shock on the mechanical properties was determined via tensile tests; SEM, DCS, and XRD were used to determine the effect of thermal shock on the corrosion products. In addition, the corrosion resistance of the products was ascertained through electrochemical testing. The results show that the mechanical properties and fatigue life of the aluminum alloy will decline with prolonged thermal shock time. The thermal shock process may result in denser surface corrosion products than those formed on the no thermal shock specimens, and transformation of some Al（OH）_3 into Al OOH. Al OOH may have resulted in improved corrosion resistance and hence a lower decrease in the fatigue life after corrosion, compared with that of the no thermal shock specimen. Repeated corrosion/thermal shock may have delayed further decease in the fatigue life. Therefore, selection of an appropriate equivalent thermal shock temperature and time was essential for designing the environmental spectrum.

Raman Spectrum and Thermal Stability of a Newly Developed TeO_2-BaO-BaF_2-La_2O_3-LaF_3 Glass

In this work, a new TeO2-BaO-BaF2-La2O3-LaF3 oxyfluorotellurite glass system is investigated. Differential thermal analysis (DTA) and structural analysis by Raman scattering spectra are reported on the glasses. The DTA results indicated that an increase of fluoride content in the glasses decreases the glass transition temperature (Tg) and increases the crystallization onset temperature (Tx). As a result the 70TeO2·20BaF2·10LaF3 glass showed a large Hruby's parameter, possessing excellent thermal stability. Changes in glass network structure with fluoride content are discussed based on the Raman scattering spectra of glasses. The glass network structures in the 70TeO2·4(20-x)BaO·xBaF2·(10-y)La2O3·yaF3 glasses are basically composed of both Te(O, F)4 and Te(O, F)3 units, but the Te(O, F)4/Te(O, F)3 ratio in the glass becomes higher with increasing fluoride content. This may be considered one of the reasons why the 70TeO2·20BaF2·10LaF3 glass exhibits excellent thermal stability.

Simulation of the Traweling Wave Burning Regime on Epithermal Neutrons

New results of two computer experiments on modeling of superthermal neutron-nuclear combustion of natural uranium for two different flux densities of external neutron source and duration of half a year each are presented. The simulation results demonstrate the dependence of the autowave combustion modes on the parameters of the external source.

Thermal Evaporation Deposition of Few-layer MoS_2 Films

We present a study of the fabrication of monolayer MoS_2 on n-Si(111) substrates by modified thermal evaporation deposition and the optoelectrical properties of the resulting film. The as-grown MoS_2 ultrathin film is about 10 nm thick, or about a few atomic layers of MoS_2. The film has a large optical absorption range of 300-700 nm and strong luminescence emission at 682 nm. The optical absorption range covered almost the entire ultraviolet to visible light range, which is very useful for making high-efficiency solar cells. Moreover, the MoS_2/Si heterojunction exhibited good rectification characteristics and excellent photovoltaic effects. The power conversion efficiency of the heterojunction device is about 1.79% under white light illumination of 10 m W/cm^2. The results show that the monolayer MoS_2 film will find many applications in high-efficiency optoelectronic devices.

Alkyl group functionalization-induced phonon thermal conductivity attenuation in graphene nanoribbons

We calculated the room-temperature phonon thermal conductivity and phonon spectrum of alkyl group-functionalized zigzag graphene nanoribbons(ZGNRs) with molecular dynamics simulations. The increase in both chain length and concentration of alkyl groups caused remarkable reduction of phonon thermal conductivity in functionalized ZGNRs. Phonon spectra analysis showed that functionalization of ZGNR with alkyl functional groups induced phonon–structural defect scattering, thus leading to the reduction of phonon thermal conductivity of ZGNR. Our study showed that surface functionalization is an effective routine to tune the phonon thermal conductivity of GNRs, which is useful in graphene thermal-related applications.

Near-zero thermal expansion of In2(1-x)(HfMg)xMo3O12 with tailored phase transition

Solid solutions of In2（1-x）（HfMg）xMo3O12 are synthesized by solid state reaction with the aim to reduce the phase transition temperature of In2Mo3O12 and improve its thermal expansion property.The effects of（HfMg）^6＋ incorporation on the phase transition and thermal expansion are investigated.It is shown that the monoclinic-to-orthorhombic phase transition temperature obviously decreases and the coefficient of thermal expansion（CTE） of the orthorhombic becomes less negative and approaches to zero with increasing the content of（HfMg）^6＋.A near zero thermal expansion covering the case at room temperature（RT） is achieved for the solid solutions with x ≥ 0.85,implying potential applications of this material in many fields.

Characteristics of emissive spectrum and the removal of nitric oxide in N_2/O_2/NO plasma with argon additive

Although the approach using non-thermal plasma（NTP） for deNOx has been studied for over 15 years,how to achieve higher removal effciency with lower cost is still a barrier for its industrial application.In order to investigate the impact of the argon additive on electron density,energy and nitric oxide reduction process in plasma,the spectrum of the dielectric barrier discharge at atmospheric pressure in a coaxial reactor was measured using the monochromater with high resolution.The comparative experiments for NO reduction were carried out simultaneously in N2/O2/NO plasma stream with and without argon,respectively.The nitrogen molecular spectrum which is attributed to the energy level transition（C^3πu→ B^3πg） was compared in the wavelength range 300-480 nm and the electron density and temperature were determined based on the relative intensities and Stark broadening width of spectral lines.The spectrum results indicated that the argon additive could enhance the intensity of emissive spectrum of plasma,thus the electron concentration as well as the energy was increased,and finally prompted the ionization rate to produce active N,O and O3.The results of NO reduction showed that NO conversion effciency increased in the range of 10%-30% with 5% addition of argon in stream comparing with the condition without argon additive.This study will play a positive role in the industrial application of dielectric barrier discharge deNOx reactor.

Analysis of Thermal Infrared Anomalies for the April16,2013M_W7.8of Khash, Iran Earthquake

After using the "Time-Frequency Relative Power Spectrum"( T-F RPS) method based on the China Geostationary Meteorological Satellite( FY-2 C/FY-2 E) infrared remote sensing brightness temperature data processing,we rapidly and accurately extracted and identified pre-earthquake thermal infrared anomalies for the April 16,2013 MW7. 8 of Khash,Iran Earthquake. Spatial evolution of anomalies showed the distribution and process. The anomalies were mainly distributed in the east of Khash,Iran. The characteristics of process and distribution presented X-Type model of NE and near NS strip which relates to the geological structure of this region. The epicenter was located near the intersection region of the X-Type abnormal migration process. Besides,the results of time series of anomalies showed that,the duration was more than 40 days and the maximum amplitude was about18 times. The earthquake occurred 20 days after the abnormal maximum amplitude which appeared on March 26,2013.

燃煤锅炉温度场与高温腐蚀气氛场同步在线检测装置开发及应用

燃煤锅炉主燃区燃烧场的经济性、安全性和环保性对于智慧电厂建设具有重要意义。其中,水冷壁近壁面高温腐蚀H_(2)S和CO气体浓度的实时在线监测尤为重要。为实现燃煤锅炉主燃区温度场和高温腐蚀气氛场的同步测量,基于红外热成像原理,采用Optris-PI1M小型红外热成像仪,基于LabVIEW温度实时采集应用软件,在炉膛的观察口对主燃区温度场进行连续监测。以低成本1.5μm附近的通信波段激光器作为测量高温腐蚀气体H_(2)S和CO的激光光源,并结合波长调制光谱技术和频分复用技术,以实现H_(2)S和CO气体浓度的同步检测。线性度实验表明,其线性拟合相关系数为0.9995。将研制的同步检测仪器对某300 MW四角切圆燃煤锅炉的主燃区的温度场和气氛场进行了现场应用试验。现场测试结果表明,锅炉主燃区温度主要分布范围在1300~1400℃,最高温度达到了1500℃;同时得到了锅炉主燃区的H_(2)S和CO浓度分布,H_(2)S浓度在12~125 mg/m^(3)的范围内波动,而CO浓度主要分布在10%~20%之间,最高可达22%;炉内H_(2)S和CO的浓度呈正相关,氧气浓度保持在1%以下,由于厌氧燃烧会导致两种气体的含量增加,从而造成对水冷壁近壁面的高温腐蚀。

Polysilicon Prepared from SiCl_4 by Atmospheric-Pressure Non-Thermal Plasma

Non-thermal plasma at atmospheric pressure was explored for the preparation of polysilicon from SiCl4. The power supply sources of positive pulse and alternating current （8 kHz and 100 kHz） were compared for polysilicon preparation. The samples prepared by using the 100 kHz power source were crystalline silicon. The effects of H2 and SiCl4 volume fractions were investigated. The optical emission spectra showed that silicon species played an important role in polysilicon deposition

热效应作用下高功率薄片涡旋激光器的模场结构

激光介质热效应引起的谐振腔模场结构变化成为高功率涡旋激光器的一个关键问题.本文建立了环形光泵浦薄片激光晶体的温度场及热形变计算模型,将热效应像差作为谐振腔衍射积分方程的微扰,研究热效应对激光器模场结构的影响规律.具体研究了Nd:YAG,Nd:YLF和Nd:YVO_(4)薄片涡旋激光器的模场结构随泵浦功率、晶体吸收系数、晶体厚度的变化规律.研究结果表明,热效应使涡旋激光器模谱产生径向展宽,模式纯净度下降.泵浦功率越大,高阶径向模式占比越大,模场结构越复杂.泵浦功率升高时,Nd:YVO_(4)激光器的模谱展宽最大,Nd:YAG激光器的模谱展宽最小.晶体吸收系数越大,模谱展宽越严重;激光晶体厚度减小时,模谱展宽呈增宽趋势.

不同产地蓝铜矿矿物学及谱学特征研究

蓝铜矿是含铜的碳酸盐矿物,它产于铜矿床的氧化带,是一种次生矿物,因此蓝铜矿的出现可作为寻找原生铜矿床的标志。国内学者对蓝铜矿的谱学研究比较少,且对世界不同著名产地蓝铜矿矿物学与谱学特征对比是空白区。通过扫描电镜能谱分析仪、粉晶X射线衍射仪、同步热分析仪、红外光谱仪等仪器对2块中国产地蓝铜矿矿物样品(安徽六峰山、广东阳春)与2块外国产地蓝铜矿矿物样品(老挝、澳大利亚)的成分、结构及谱学特征进行了分析与探讨。能谱元素分析结果显示4块矿物样品的主要元素为C、O、Cu三种元素。X衍射结果表明除产于安徽六峰山矿物外,其他3种产地矿物X衍射物相分析结果均为蓝铜矿Cu_(3)(OH)_(2)(CO_(3))_(2)。产于安徽六峰山矿物除了主物相蓝铜矿的衍射峰外,在其他位置也检测出衍射峰,表明产于安徽六峰山的矿物含有第二物相孔雀石CuCO_(3)·Cu(OH)_(2)。从同步热分析仪热重曲线可以看出主要有两个失重台阶,300℃之前的失重可能是蓝铜矿中含有小部分的孔雀石的分解失重,而300~600℃的失重对应的是蓝铜矿的分解失重。从红外光谱上看主要的红外峰为蓝铜矿的特征峰,四个不同产地的红外光谱比较相似。结合蓝铜矿的外观特征,可为不同产地蓝铜矿的产地鉴定和检测提供依据。

近红外光谱传感器的测点热误差补偿方法设计

红外光谱传感器测量受测点不合理产生的热误差影响存在测量偏差较大的问题。提出一种近红外光谱传感器测点热误差补偿方法。根据近红外光谱传感器热变形和测点温度之间的关联性,确定近红外光谱传感器最佳测温点。根据偏F统计量的检验在回归模型中加入拟合处理后的温度变量,删除前期无利用价值的温度变量,以此为依据建立测点热误差模型。根据测点热误差模型中的约束条件,对各个测点进行标定处理,同时引入人工神经网络对近红外光谱传感器各个测点进行温度拟合补偿。实验结果表明,所提方法得到的测点热误差补偿量最高值为45μm、对丝杠XYZ三个轴的补偿量与实际值一致、补偿后的误差控制在4.5μm以内。证明采用所提方法可以获取满意的近红外光谱传感器温度补偿结果。

Phase transition and near-zero thermal expansion of Zr_(0.5)Hf_(0.5)VPO_7

The Zr（0.5）Hf（0.5）VPO7 is successfully synthesized by the solid-state method with near-zero thermal expansion. Powder x-ray diffraction（XRD）, Raman spectroscopy, thermal dilatometry, and scanning electron microscopy（SEM） are used to investigate the structure, the phase transition, and the coefficient of thermal expansion（CTE） of Zr（0.5）Hf（0.5）VPO7. The investigation results show that the samples are of the single cubic type with a space group of Pa3ˉ at room temperature（RT）.It can be inferred that the superstructure is transformed from the 3 × 3 × 3 superstructure to the 1 × 1 × 1 ideal crystal in a temperature range between 310 K and 323 K. The CTE is measured by a dilatometer to be 0.59 × 10^（-6） K^（-1）（310 K–673 K）. The values of intrinsic（XRD） and extrinsic（dilatometric） thermal expansion are both near zero. The results show that Zr（0.5）Hf（0.5）VPO7 has near-zero thermal expansion behavior over a wide temperature range.

新能源汽车电池的在线监测与原位分析技术

为控制新能源汽车电池耗电量,并对其电能消耗行为进行原位分析,针对新能源汽车电池的在线监测与原位分析技术展开研究。完善动力锂电池组结构模型,根据汽车电池的热耦合特性,推导监测核函数,实现新能源汽车电池的在线监测。在此基础上,确定汽车电池的电极材料,并分别从表征特性、拉曼光谱两个角度,对其电池元件的原位特性进行研究。

Thermal aging behavior of high performance poly(vinyl alcohol) hydrogel

The thermal aging behavior of poly （ vinyl alcohol ） （ PVA ） hydrogel was studied at four different temperatures of 40 ℃, 50 ℃, 60 ℃ and 70 ℃ in one year. The samples of PVA hydrogel were closely covered by plastic film. The changes of their chemical structures and physical properties during aging were measured through different measurable techniques including tensile testing, gel permeation chromatography （ GPC ）, viscosity analysis, and Fourier transform infrared （FTIR） spec- trum. The results showed that the molecular weight of PVA in hydrogel changed little with time and temperature. FTIR spectra of PVA in all the samples were similar to those of the original samples. The tensile strength of PVA hydrogel didn＇t change until the 330th days.

锂基脂静态热氧化老化行为的红外吸收光谱定量分析

为探讨锂基润滑脂在高温使用工况下的热老化行为,以不同矿物油、合成油PAO为基础油,以12-羟基硬脂酸锂为稠化剂制备润滑脂样品。使用自行设计的红外光谱定量分析设备,采用静态热老化方式模拟并系统研究了不同老化温度、不同基础油种类的锂基润滑脂老化过程。探索了该老化过程中的润滑脂中关键组分分子结构变化及其规律,并分析建立了可用于有效评定润滑脂热老化程度的综合性能指标E。结果表明:锂基润滑脂的热老化过程中,首先基础油发生氧化、硝化、硫化等反应,随着老化程度的加剧,稠化剂发生降解;对于140℃下静态热老化的1#锂基脂样品,E值上升至新脂的1~23倍时为初级氧化阶段,上升至23~38倍时为氧化的平台阶段,结合其他理化指标,前2个阶段为影响润滑脂寿命的主要部分,随老化时间增加,E值继续上升,润滑脂结构开始降解失效。另外,润滑脂老化程度随温度的升高而加速。基础油种类对老化速率有一定影响,聚α烯烃规整的长链烷烃结构在老化过程后期能够保持稠化剂结构的稳定,制备的润滑脂样品具有更好的高温性能。

皮秒激光驱动微丝靶产生的超热电子能谱实验研究

目的 针对激光辐照平面靶中超热电子束流发散角过大以及产生的X光源亮度不足的问题,提出采用高功率皮秒激光辐照微丝靶,研究电子再循环效应对超热电子束流和X光源特性的影响。方法 实验在“星光-Ⅲ”装置皮秒束激光器上进行,分别采用直径10μm的钼和金丝靶作为X射线背光源。利用针孔相机在激光反射方向测量X光焦斑,靶前法线方向布置电子磁谱仪测量逃逸出靶的超热电子能谱。结果 获得的X光焦斑的纵向尺寸最小值达到10μm,与丝靶直径相当。超热电子能谱结果显示自持独立钼丝和金丝中最高温度分别为863 keV和816keV,比对应的带CH衬底丝靶中的超热电子温度和数目均有显著提升。结论 说明移除支撑丝靶的低密度衬底是增强电子再循环效应的有效途径,通过这种方式能够提高超热电子束流的强度和集中度,增强轫致辐射强度,从而获得微焦点和高亮度的X射线源。

基于法布里-珀罗干涉仪测量大气环境CO_(2)的方法

CO_(2)是主要的温室气体之一,它的排放和累积导致温室效应加强,进而引起全球气候变化,因此获取大气环境中CO_(2)的浓度变化对研究气候变化意义重大.针对低成本、快速和在线精确测量大气环境CO_(2)的技术需求,本文构建了基于法布里-珀罗干涉仪的CO_(2)大气浓度在线测量系统,并研究了精确获取其浓度反演方法.采用基于微机电系统(MEMS)技术的热辐射源作为法布里-珀罗干涉仪系统光源,设计透射式光路代替常见的折射式光路.通过静电控制两镜片的间距,改变干涉谱,实现10 nm步长的中心波长的干涉峰调节,扫描获得CO_(2)实时在线吸收光谱,基于差分吸收光谱原理获取了CO_(2)气体的浓度.利用样气标定系统,并用商用光声光谱多气体分析仪校验系统,结果表明,该系统检测限达1.09×10^(-6),检测精度为±1.13×10^(-6),测量误差小于1%.在煤城淮北开展了大气环境CO_(2)实时在线检测,并与商用光声光谱分析仪开展比对观测实验,二者相关系数R=0.92.实验结果表明,研发的法布里-珀罗干涉仪系统能够满足大气环境CO_(2)浓度的快速、在线高精度测量技术需求.

基于热分析图谱的卷烟配方原料分类分档模型构建与应用

【目的】提高卷烟配方原料分类分档的工作效率,帮助配方人员客观掌握配方原料的年度间波动。【方法】提出一种热分析图谱结合支持向量机算法(SVM)对卷烟配方原料进行分类分档的新技术。采用python3中sklearn中的SVM模块,通过核函数和one-against-all方法并选择合适的惩罚参数,对2016—2018年度的129个样品进行训练学习,并对33个样品进行测试。当模型预测准确率达到应用需求后,对2019年度46个卷烟配方原料进行分类预测。【结果】129个训练集样品的分类准确率为93.02%,33个样品测试集样品的分类准确率为84.85%,46个卷烟配方原料的分类准确率为84.78%。