Spectroscopy and molecule opacity investigation on excited states of SiS

The SiS molecule,which plays a significant role in space,has attracted a great deal of attention for many years.Due to complex interactions among its low-lying electronic states,precise information regarding the molecular structure of SiS is limited.To obtain accurate information about the structure of its excited states,the high-precision multireference configuration interaction(MRCI)method has been utilized.This method is used to calculate the potential energy curves(PECs)of the 18Λ–S states corresponding to the lowest dissociation limit of SiS.The core–valence correlation effect,Davidson’s correction and the scalar relativistic effect are also included to guarantee the precision of the MRCI calculation.Based on the calculated PECs,the spectroscopic constants of quasi-bound and bound electronic states are calculated and they are in accordance with previous experimental results.The transition dipole moments(TDMs)and dipole moments(DMs)are determined by the MRCI method.In addition,the abrupt variations of the DMs for the 1^(5)Σ^(+)and 2^(5)Σ^(+)states at the avoided crossing point are attributed to the variation of the electronic configuration.The opacity of SiS at a pressure of 100 atms is presented across a series of temperatures.With increasing temperature,the expanding population of excited states blurs the band boundaries.

X-ray Spectroscopically Probing Mo_(2)C@MoSe_(2)Heterojunction Electrodes

Due to their high electrical conductivity and layered structure,two dimensional MXene materials are re⁃garded as promising candidates for energy storage applications.However,the relatively low stability and specific ca⁃pacity of MXene materials limit their further utilization.In this study,these issues are addressed using a heterostruc⁃ture strategy via a one-step selenization method to form Mo_(2)C@MoSe_(2).Synchrotron radiation X-ray spectroscopic and high-resolution transmission electron microscopy(HRTEM)characterizations revealed the heterostructure consisting of in-situ grown MoSe_(2)on Mo_(2)C MXene.Electrochemical tests proved the heterojunction electrode’s superior rate perfor⁃mance of 289.06 mAh·g^(-1)at a high current density of 5 A·g^(-1)and long cycling stability of 550 mAh·g^(-1)after 900 cycles at 1 A·g^(-1).This work highlights the useful X-ray spectroscopic analysis to directly elucidate the heterojunction structure,providing an effective reference method for probing heterostructures.

A Smart Fluorescent Light Spectroscope to Identify the Pork Adulteration for Halal Authentication

The complication of adulterated ingredients in processed food items is widely observed in the food industry and remains a continuous disquiet for end users. This problem may affect consumers’ spiritual beliefs, likewise with their fitness and diet. Hence commercial foods should be scrutinized for the precision of the avowed ingredients. This study is dedicated to developing a Fluorescent light Spectroscope to identify the pork adulteration. A simple way of DNA extraction process has been introduced to make the system more convenient. The spectral bands linked with pork fat (PF), beef fat (BF) and their combinations in different food formulation were skimmed, and recognized by correlating them to those spectroscopically illustrative to clean Pork or PF and other different items. Every material has the properties to absorb some light of specific wavelength, and our activity is to determine thus wavelength range at which are absorbed or make any change by the target material. The findings have revealed that spectroscopy can be used as one of the procedures to detect and quantify of pork in different foods and beverages formulation for Halal verification purposes. Special laborious procedures and equipment both are essential for the existing testing methods named RT-PCR (Reverse transcription-polymerase chain reaction) and ELISA (enzyme-linked immunosorbent assay). Most of the food processors and dealers are not skillful to conduct sufficient testing for their products with all these sample preparation, extraction, analysis, and obtaining results which can be overcome by our proposed setup.

Kiso Multi-Fiber Spectroscope Project

A multi Fiber Spectroscope at Kiso Observatory is under consideration as our next instrument. In this paper we report an overview of our instrument and a scientific target of survey project. We are going to attach multi fiber system at the prime focus of Kiso 150m Schmidt telescope. This telescope has some advantage for our project. First, the effciency in survey for the objects, which number density is 0 1 to 10/degree 2, is higher than other multi object system due to the wide field of view (6 °×6 °). Second, an optics of telescope is well matched to fiber numerical aperture (NA) at an input end of fiber. Moreover, taking a focal ratio degradation (FRD) and scrambling property into account, since the light from object does not move at the entrance slit of spectroscope, we could get spectroscopic data stably with this system. We select a fiber with 100μm core which corresponding to 6 arcsec on focal plane, that is matched with a typical seeing (3 arcsec) at Kiso Observatory and set 150 fibers to one field. For efficient observations, it is necessary to arrange fibers accurately within an accuracy of ±25μm on the curved focal plane during a typical exposure time (1 hour). Therefore we examine a particular positioner specialized for curved surface. We also develop a spectroscope that is suited for a fast focal ratio and proceed with making its design. One of our main key projects with this system is a non biased survey for solar neighbour stars. We are now establishing a new metallicity determination method that easily and reliably measures a metallicity from low dispersion spectra. (see Itoh it et al. 1998) As we consider our main target as Galactic objects and low resolution (R is around 1000), we could observe a star with 17 mag at V band (1 hour exposure).

Optical Spectroscopy of Classical Be Stars in Old Open Clusters

We performed the optical spectroscopy of 16 classical Be stars in 11 open clusters older than 100 Myr.Ours is the first spectroscopic study of classical Be stars in open clusters older than 100 Myr.We found that the Hαemission strength of most of the stars is less than 40?,in agreement with previous studies.Our analysis further suggests that one of the stars,[KW97]35–12,might be a weak Hαemitter in nature,showing Hαequivalent width of-0.5?.Interestingly,we also found that the newly detected classical Be star LSⅢ+4737b might be a component of the possible visual binary system LSⅢ+4737,where the other companion is also a classical Be star.Hence,the present study indicates the possible detection of a binary Be system.Moreover,it is observed that all 16 stars exhibit a lesser number of emission lines compared to classical Be stars younger than 100 Myr.Furthermore,the spectral type distribution analysis of B-type and classical Be stars for the selected clusters points out that the existence of CBe stars can depend on the spectral type distribution of B-type stars present in these clusters.

Vibrational spectroscopy-are we close to finding a solution for early pancreatic cancer diagnosis?

Pancreatic cancer(PC)is an aggressive and lethal neoplasm,ranking seventh in the world for cancer deaths,with an overall 5-year survival rate of below 10%.The knowledge about PC pathogenesis is rapidly expanding.New aspects of tumor biology,including its molecular and morphological heterogeneity,have been reported to explain the complicated“cross-talk”that occurs between the cancer cells and the tumor stroma or the nature of pancreatic ductal adenocarcinoma-associated neural remodeling.Nevertheless,currently,there are no specific and sensitive diagnosis options for PC.Vibrational spectroscopy(VS)shows a promising role in the development of early diagnosis technology.In this review,we summarize recent reports about improvements in spectroscopic methodologies,briefly explain and highlight the drawbacks of each of them,and discuss available solutions.The important aspects of spectroscopic data evaluation with multivariate analysis and a convolutional neural network methodology are depicted.We conclude by presenting a study design for systemic verification of the VS-based methods in the diagnosis of PC.

Benchmarking calculations of excitation energies and transition properties with spectroscopic accuracy of highly charged ions used for the fusion plasma and astrophysical plasma

Atomic radiative data such as excitation energies, transition wavelengths, radiative rates, and level lifetimes with high precision are the essential parameters for the abundance analysis, simulation, and diagnostics in fusion and astrophysical plasmas. In this work, we mainly focus on reviewing our two projects performed in the past decade. One is about the ions with Z■30 that are generally of astrophysical interest, and the other one is about the highly charged krypton(Z = 36)and tungsten(Z = 74) ions that are relevant in research of magnetic confinement fusion. Two different and independent methods, namely, multiconfiguration Dirac–Hartree–Fock(MCDHF) and the relativistic many-body perturbation theory(RMBPT) are usually used in our studies. As a complement/extension to our previous works for highly charged tungsten ions with open M-shell and open N-shell, we also mainly focus on presenting and discussing our complete RMBPT and MCDHF calculations for the excitation energies, wavelengths, electric dipole(E1), magnetic dipole(M1), electric quadrupole(E2), and magnetic quadrupole(M2) transition properties, and level lifetimes for the lowest 148 levels belonging to the 3l3configurations in Al-like W61+. We also summarize the uncertainties of our systematical theoretical calculations, by cross-checking/validating our datasets from our RMBPT and MCDHF calculations, and by detailed comparisons with available accurate observations and other theoretical calculations. The data are openly available in Science Data Bank at https://doi.org/10.57760/sciencedb.10569.

钢渣基盾粉/橡胶复合材料的性能及机理

基于利用超细立磨与钢渣制备钢渣基盾粉(简称盾粉)的研究成果,以橡胶工业配方制备盾粉/橡胶复合材料。测试矿物成分、化学成分、粒度分布、结构组成、微观结构和热稳定性,从微观层面阐述盾粉用于橡胶工业配方的相关机理。结果表明:当盾粉替代炭黑比例为5%~10%(质量分数,下同)时,盾粉与橡胶基体的相容性较好,盾粉/橡胶复合材料拉伸强度为16.16~17.06 MPa,高于15 MPa,拉伸伸长率为619.8%~668.21%,高于350%,磨耗量为130~196 mm^(3),小于200 mm^(3),均满足国标要求;当盾粉替代炭黑比例为5%时,盾粉/橡胶复合材料的硫化时间缩短、硫化速率指数提高。盾粉/橡胶复合材料燃烧时,一方面盾粉中SiO2与硫自由基、Fe、Zn、Al发生反应形成Si-Mg阻燃体系、Si-Al阻燃体系与Si-Fe消烟体系;另一方面盾粉与橡胶体系产生关联作用组成致密的炭层,阻止部分热量的传递与火焰的蔓延。

光谱技术在果树叶片营养诊断上的应用研究进展

光谱技术具有分析速度快、操作简单、多元素同时监测、不需要消耗化学药品、自动化程度较高等特点,其可以实现作物单株和大样本的营养诊断和分析。综述了光谱技术在果树叶片大量元素(N、P、K)、中微量元素(Ca、Mg、Fe、Mn、Cu、Zn)营养诊断上的应用研究进展,并讨论了该领域今后进一步的研究方向。

荧光增白剂与人血清白蛋白相互作用的多种光谱法及分子对接技术研究

通过多种光谱方法与分子对接技术,从分子水平上对两种荧光增白剂(C.I.135、C.I.185)与人血清白蛋白(HSA)的相互作用机制进行研究。稳态荧光光谱及紫外-可见光谱实验结果表明,C.I.135、C.I.185与HSA均形成了基态复合物(HSA-C.I.135、HSA-C.I.185),猝灭机理为静态猝灭机理,热力学参数表明氢键与范德华力是结合作用的主要作用力,并且结合过程都是自发进行。三维荧光光谱结果表明C.I.135、C.I.185可以改变HSA的氨基酸残基微环境和构象,C.I.185对HSA产生的影响是最大的。分子模拟实验进一步验证上述实验结果。

基于自适应滤波的暗电流消除设计

暗电流作为光电探测器的固有噪声,是影响双光束分光光度计检测性能的重要因素。为消除此影响,提出自适应滤波双光束分光光度计。首先,设计实时暗电流检测系统,能在每个检测周期内捕获样品信号、参考信号和暗电流信号。其次,针对时域差异引起的暗电流消除问题,引入自适应级联滤波算法(Recursive Least Squares and Normalized Least Mean Squares,RLS-NLMS),算法采用三级级联滤波模型,一级局部均值(Local Mean,LM)降低暗电流与检测信号之间的相关性,二级低阶RLS滤波器用于检测信号滤波,三级高阶NLMS滤波器用于处理RLS输出信号。实验结果显示,自适应滤波双光束分光光度计的透射比相对误差仅为1.46%,较传统方法降低了66%,在暗电流消除方面表现出色,具有实际应用价值。

SiTe分子激发态光谱性质的理论研究

采用多参考组态相互作用(MRCI)的方法研究了Si Te分子的电子结构,获得18个Λ-S态的势能曲线.基于势能曲线(PECs)通过数值积分方法获得电子态的光谱常数.计算Si Te分子的电偶极矩(PDMs)并分析电子组态的变化对电偶极矩的影响.此外,计算得到的势能曲线表明,11Π和13Π态与附近的5个电子态(13Σ^(+),13Δ,11Σ^(-),13Σ^(-),11Δ)在16500~27400 cm^(-1)的能量区域内密集分布,邻近的电子态对13Π态有明显的扰动作用.通过11Π和13Π态的自旋-轨道耦合矩阵元,分析电子组态与自旋-轨道耦合矩阵元的关系.最后,计算了SiT e分子21Σ^(+)-X1Σ^(+),13Π-13Δ,11Π-X1Σ^(+),13Π-13Σ^(-)和13^(+)Σ^(-)13Π的跃迁偶极矩(TDM)以及11Π-X1Σ^(+)和21Σ^(+)-X1Σ^(+)的辐射寿命.

糖尿病周围神经病变多模态MRI研究进展

糖尿病周围神经病变(diabetes peripheral neuropathy,DPN)是较常见的糖尿病慢性并发症,严重影响患者生活质量。DPN发病机制比较复杂,目前研究表明与神经病理性改变关系密切。近些年多模态MRI获得长足进展,MRI以软组织分辨率高、无创、无辐射等优点著称,成为探索DPN中枢神经及周围神经发病机制的重要方法。本文应用基于体素的形态学测量(voxel-based morphometry,VBM)、弥散张量成像(diffusion tensor imaging,DTI)、功能MRI(functional MRI,fMRI)等技术,对研究DPN脑结构、脑功能改变以及周围神经结构异常的文献进行综述,为临床早期诊断和制订精准治疗方案提供依据。

夹心饼干缺陷在线检测系统的设计

为了降低饼干企业用人成本、提升夹心饼干产品质量,设计了安装于夹心机内的小型一体化的饼干缺陷检测视觉系统和处理算法,采用分光系统将一次拍摄分别在2个相机成像,分别用于对饼胚和馅料的检测,该结构能够同时对饼胚和馅料的各种生产过程中可能产生的缺陷进行在线检测和自动剔除。工程应用表明,该系统调试方便、检测稳定且精度高,具有良好的推广应用价值。

基于多光谱技术分析绿原酸与肌原纤维蛋白相互作用的初步研究

本研究以高白鲑肌原纤维蛋白(Myofibrillar Protein,MP)为研究对象,探究不同浓度(6、30、150、300μmol/g)绿原酸(Chlorogenic Acid,CA)与MP相互作用的结构变化及结合性质。在25℃下孵育形成不同CA-MP复合物,通过测定复合物的理化性质(总巯基,表面疏水性),二级,三级结构变化(傅里叶红外光谱、同步荧光、三维荧光),结合性质(紫外光谱,荧光猝灭及热力学参数)分析CA-MP复合物相互作用情况。结果表明,在300μmol/g CA存在下,蛋白总巯基含量和表面疏水性分别骤降25.65%,40.26%(P<0.05);蛋白质二级结构随之展开,α-螺旋含量下降至11.73%,造成蛋白结构稳定性降低;同步荧光与三维荧光光谱表明CA对蛋白荧光具有猝灭作用,且色氨酸比酪氨酸的猝灭效果高7.90%。紫外光谱和荧光猝灭证实CA-MP形成复合物且二者的结合为静态猝灭,热力学参数进一步验证二者相互作用的主导力为疏水作用力。本研究旨在为多酚与高白鲑MP相互作用提供有价值的信息,为后续对不同结构多酚与高白鲑肌球蛋白的相互作用机制提供研究基础。

鞣花酸抑制酪氨酸酶的动力学、荧光光谱分析及分子对接

以蘑菇酪氨酸酶为靶点,采用抑制动力学、荧光光谱分析结合分子对接模拟技术,系统研究鞣花酸(ellagic acid,EA)对酪氨酸酶的抑制作用及机理。体外研究与动力学结果表明,EA以可逆的混合型抑制方式显著抑制酪氨酸酶活性(IC_(50)=0.05mg/mL),其结合常数K_(I)<K_(IS),表明EA与游离酶的结合比与酶-底物复合物的结合更紧密。荧光光谱猝灭分析表明,EA与酪氨酸酶存在静态猝灭作用,两者通过自发的吸热过程结合生成复合物,主要作用力为疏水作用力,只有1个或1类结合位点。同步和三维荧光光谱分析表明,EA使酪氨酸酶的微环境极性增大,疏水能力减弱,酪氨酸酶的Trp残基更靠近结合位点。分子对接模拟分析进一步印证上述实验结果,形象地表明EA对酪氨酸酶为混合型抑制,EA主要通过疏水作用力和氢键与游离酶或酶-底物复合物进行结合,最终导致酶活性降低。本研究对EA在食品工业中作为保鲜剂的各种应用具有一定参考意义。

光声光谱技术应用于痕量气体浓度测量的研究进展

光声光谱技术作为实现痕量气体浓度高效率、高精度测量的重要气体传感技术,因其响应速度快、灵敏度高、选择性好等优点被广泛应用到大气环境检测、电力系统故障诊断、医疗健康诊断等领域当中。首先介绍了光声光谱技术痕量气体浓度测量的基本原理,对应用光声效应实现痕量气体浓度测量的机理进行了简要的描述,同时,介绍了基于光声光谱技术的典型痕量气体浓度测量装置的结构。其次,从光声信号强度的理论分析出发,引出国内外学者在光声光谱痕量气体浓度测量领域的研究热点,为了实现基于光声光谱技术的痕量气体浓度测量装置更强的抗干扰能力、更紧凑的结构、更低的检测下限、更高的检测灵敏度,国内外学者的研究重点可以总结为以下三点:(1)辐射光源的选取和设计,以实现更佳辐射光源的输出波长、更宽的调谐范围、更高的辐射光源输出功率。(2)更优秀的光声池设计,以实现更高效的声能量积聚、更紧凑的结构和更强的抗干扰能力。(3)声敏探测器的设计,以实现更高的声音灵敏度、更高的信噪比。详细介绍了基于光声光谱痕量气体浓度测量装置的三个核心元件:辐射光源,主要介绍了相干光源和非相干光源的应用研究进展;光声池,主要介绍了光声池的设计原则以及非共振式和共振式光声池的应用研究进展;微音器,主要介绍了电容式微音器、压电式微音器的应用研究进展,并对近期研究热点石英增强光声光谱技术进行简要的介绍。在介绍目前辐射光源、光声池、微音器应用研究进展的同时,分析了各元件的优势和需要解决的问题。最后,总结了光声光谱技术应用于痕量气体浓度测量领域装置存在的信噪比不高、结构复杂、检测灵敏度和检测下限易受混合气体之间的交叉干扰等问题,并且对未来测量装置中的三个核心元件:辐射光源、光声池、微音器的发展趋势进行了展望。

掺铒CaF_(2)、SrF_(2)、PbF_(2)晶体的光谱性能与团簇结构研究

3μm波段中红外激光处于大气传输窗口,又可以作为基础光源,是激光技术研究的前沿。目前,铒离子激活的激光晶体材料是产生3μm中红外激光的重要途径之一。然而,Er3+离子4I11/2激光上能级荧光寿命较短,下能级4I13/2的寿命较长,难以实现粒子数反转,导致自终止现象。为了解决这一难题,往往需要高浓度掺杂,通过能量传递降低4I13/2能级的寿命。然而高浓度掺杂又会造成晶体热性能变差,限制了掺Er3+激光晶体效率和功率。三阶铒离子容易在氟化物晶体中形成团簇,导致稀土离子间距缩短,即使在低掺杂浓度下稀土离子之间的能量传递作用仍较为显著。同时,低浓度掺杂还可以减轻激光运转下晶体的热堆积效应。掺铒氟化物晶体已成为一类重要的高功率、高效率中红外激光材料。然而,掺铒氟化物晶体的光谱性能与铒离子团簇结构之间的相互联系尚不明确,制约了掺铒氟化物晶体光谱和激光性能的进一步发展。本文采用第一性原理计算模拟了铒离子在CaF_(2)、SrF_(2)和PbF_(2)晶体中的团簇结构。结果显示,铒离子团簇结构随基质晶体变化逐渐演变。结合模拟计算和实验表征定性揭示了不同晶体离子团簇与光谱性能的联系,为掺铒氟化物中红外激光晶体材料的调控与设计提供参考。

Oxygen‑Coordinated Single Mn Sites for Efficient Electrocatalytic Nitrate Reduction to Ammonia

Electrocatalytic nitrate reduction reaction has attracted increasing attention due to its goal of low carbon emission and environmental protection.Here,we report an efficient NitRR catalyst composed of single Mn sites with atomically dispersed oxygen(O)coordination on bacterial cellulose-converted graphitic carbon(Mn-O-C).Evidence of the atomically dispersed Mn-(O-C_(2))_(4)moieties embedding in the exposed basal plane of carbon surface is confirmed by X-ray absorption spectroscopy.As a result,the as-synthesized Mn-O-C catalyst exhibits superior NitRR activity with an NH_(3)yield rate(RNH_(3))of 1476.9±62.6μg h^(−1)cm^(−2)at−0.7 V(vs.reversible hydrogen electrode,RHE)and a faradaic efficiency(FE)of 89.0±3.8%at−0.5 V(vs.RHE)under ambient conditions.Further,when evaluated with a practical flow cell,Mn-O-C shows a high RNH_(3)of 3706.7±552.0μg h^(−1)cm^(−2)at a current density of 100 mA cm−2,2.5 times of that in the H cell.The in situ FT-IR and Raman spectroscopic studies combined with theoretical calculations indicate that the Mn-(O-C_(2))_(4)sites not only effectively inhibit the competitive hydrogen evolution reaction,but also greatly promote the adsorption and activation of nitrate(NO_(3)^(−)),thus boosting both the FE and selectivity of NH_(3)over Mn-(O-C_(2))_(4)sites.

环金属配体Ir(Ⅲ)配合物结构、光谱和量子效率的理论研究

对一类环金属Ir(Ⅲ)[(C^N)_(2)Ir(A^A)]配合物[C^N=ptaz(1,2,4),mhtz(3),ptaz=3,4,5-三苯基-4H-1,2,4-三唑,mhtz=1,3-双甲基-5-苯基-1H-1,2,4-三唑;A^A=pzpy(1),npzpy(2,3),bicb(4),pzpy=2-(1H-吡唑-1-基)吡啶,npzpy=4-二甲基氨基-2-(1H-吡唑-1-基)吡啶,bicb=3,3′-亚甲基双(1-甲基-1H-咪唑-2-亚基)]的结构、光谱特征和磷光量子效率进行了理论研究.计算方法探究表明,基于B3LYP泛函优化的基态结构和单激发组态相互作用(CIS)方法得到的激发态结构计算的吸收和发射光谱更准确.配合物1~4的最低吸收峰和发射峰分别位于408,376,382,365 nm和503,506,468,511 nm处,其HOMOs主要由金属和C^N配体占据,而配合物1~3的LUMOs由A^A配体的π反键轨道组成,配合物4的LUMO存在于C^N配体上.因此,配合物4的最低吸收峰和发射峰具有与配合物1~3不同的金属到配体和配体内部(MLCT/ILCT)的混合跃迁性质,非共轭N^N配体的引入显著消弱了其在跃迁过程中的贡献程度.配合物1~4的量子效率取决于非辐射跃迁速率常数k_(nr),这与它们重组能的贡献[4569 cm^(-1)(3)>2583 cm^(-1)(1)>1232 cm^(-1)(2)>975 cm^(-1)(4)]相一致,表明主配体的体积和辅助配体的共轭能力都能影响配合物的磷光量子效率.