Design of a Weak Signal Detecting Circuit in the Infrared Spectrum Absorbed Type Gas Sensor

In the infrared spectrum absorbed type gas concentration sensor,voltage signal obtained from the two-channel thermopile infrared detector TPS2534 is very weak.In order to solve this problem,the authors have established the structure of the sensor and designed weak signal detecting circuit of the sensor based on infrared spectrum absorption principle,differential de-noising principle and weak signal detecting principle.The authors have made experiments using CH4 gas.The results show that the circuit can remove noise effectively and detect weak electrical signal obtained from the detector.

乙酰丙酮铱Ir(acac)_(3)电子结构及光学性质的理论研究

乙酰丙酮铱是一种由过渡金属Ir与乙酰丙酮酸(acetylcaetonato)有机部分组成的过渡金属有机配合物,它是一种重要的绿光磷光材料,同时其也是多种铱系发光材料的组成部分.采用密度泛函理论(DFT)对Ir(acac)_(3)单体及其二聚物的基态几何结构进行了优化,在此基础上考察了它们的振动和红外光谱,并使用CIS方法对它们的激发态性质进行了理论研究.计算得到的单体和二聚物的吸收光谱均在紫外波段,单体的主要吸收峰有260 nm,350 nm,414 nm,二聚物的主要吸收峰有299 nm,353 nm,401 nm.计算得到了二者在乙腈CH_(3)CN溶液中的吸收光谱,与它们气相情况的结果相比,溶剂极性的影响使得电子吸收谱发生蓝移.计算结果表明Horst Kunkely和Arnd Vogler所得光谱中既含有单体的特征光谱,又含有二聚体的特征光谱,证明实验溶液中同时存在乙酰丙酮铱的低聚物,并且二者的组分比能被合理推算.最后,对多聚体的形成机理作了简单讨论.

A New Temperature Channel Selection Method Based on Singular Spectrum Analysis for Retrieving Atmospheric Temperature Profiles from FY-4A/GIIRS

Hyperspectral data have important research and application value in the fields of meteorology and remote sensing.With the goal of improving retrievals of atmospheric temperature profiles,this paper outlines a novel temperature channel selection method based on singular spectrum analysis(SSA)for the Geostationary Interferometric Infrared Sounder(GIIRS),which is the first infrared sounder operating in geostationary orbit.The method possesses not only the simplicity and rapidity of the principal component analysis method,but also the interpretability of the conventional channel selection method.The novel SSA method is used to decompose the GIIRS observed infrared brightness temperature spectrum(700-1130 cm-1),and the reconstructed grouped components can be obtained to reflect the energy variations in the temperature-sensitive waveband of the respective sequence.At 700-780 cm-1,the channels selected using our method perform better than IASI(Infrared Atmospheric Sounding Interferometer)and Cr IS(Cross-track Infrared Sounder)temperature channels when used as inputs to the neural network retrieval model.

Electronic structure and infrared spectrum of a W_n C^(0,±) (n = 1-6) cluster

WnC0＇± （n= 1-6） clusters are investigated by using the density functional theory （DFT） at the B3LYP/LANL2DZ level. We find that the neutral, anionic and cationic ground state structures are similar within the same size, and constituted by substituting a C atom for one W atom in the structures of Wn＋1 clusters. The natural bond orbital （NBO） charge analyses indicate that the direction of electron transfer is from the W atom to the 2p orbital of the C atom. In addition, the calculated infrared spectra of the WnC0＇± （n= 2-6） clusters manifest that the vibrational frequencies of neutral, anionic and cationic clusters are similar in a range of 80 cm-1-864 cm-1. The high frequency, strong peak modes are found to be an almost stretched deformation of the carbide atom. Finally, the polarizabilities of WnC0＇± （n= 1-6） clusters are also discussed.

MODIFICATION OF ABSORPTION SPECTRUM OF GaAs/AlGaAs QUANTUM WELL INFRARED PHOTODETECTOR BY POSTGROWTH ADJUSTMENT

Quantum well intermixing techniques modify the geometric shape of quantum wells to allow postgrowth adjustments.The tuning effect on the optical response property of a GaAs/AlGaAs quantum well infrared photodetector(QWIP) induced by the interdifussion of Al atoms was studied theoretically.By assuming an improvement of the heterointerface quality and an enhanced Al interdiffusion caused by postgrowth intermixings,the photoluminescence spectrum shows a blue-shifted,narrower and enhanced photoluminescence peak.The infrared optical absorption spectrum also shows the expected redshift of the response wavelength.However,the variation in the absorption peak intensity depends on the boundary conditions of the photo generated carriers.For high-quality QWIP samples,the mean free path of photocarriers is long so that the photocarriers are largely coherent when they transport across quantum wells.In this case,the enhanced Al interdiffusion can significantly degrade the infrared absorption property of the QWIP.Special effects are therefore needed to maintain and/or improve the optical properties of the QWIP device during postgrowth treatments.

Synthesis，Crystal Structure and Infrared Spectrum of Lanthanum Dinuclear Coordination Compound with Alanine：〔La2（ala）4（H2O）8〕·（ClO4）6

Lanthanum coordination compound with l-alanine[La2（ala）4（H2O）8]·（ClO4）6（ala=l-alanine） was synthesized by reaction of lanthanum perchlorate with l-alanine in aqueous solution and obtained in the form of single crystals.The X-ray crystal structure has been determined and the IR spectrum has been studied.The title compound Cl6La2C12H44O40N4,Mr=1375.2,crystallizes in the triclinic,space group P1 , with parameters: a= 11.227（3）,b=11.445（2）,c=11.014（3）,α=114.46（2）,β=114.51（2）,γ=78.62（2）°,V=1171.73,Z=1,Dc=1.95 g/cm￣3,F（000）=680,μ=22.9 cm￣-1（MoKα）.The final R=0.050,Rω=0.051.In the crystal,two lanthanum ions are coordinated by four alanine molecules via four carboxylate bridges to form a dinuclear coordination compound.Four water molecules are coordinated to each lanthanum ion. There is a symmetric centre between the two lanthanum ions.The IR spectrum of the coordination compound and the relationship between the IR spectrum and the structure have been studied.The mechanism of the configuration inversion of alanine has been proposed.

Evaluation of Expression Recognition Function in Autism Spectrum Disorder Using Near-Infrared Spectroscopy

One of the characteristics of Autism Spectrum Disorder (ASD) is social disorder. The specificity of facial and expression recognition for people with ASD is gathering attention as a factor of this social disorder. The study examined the hemodynamic activities in the prefrontal cortex using near-infrared spectroscopy (NIRS) when a person with ASD performed an expression recognition task. The subjects were twenty males (18 - 22 years old) with ASD and without intellectual disabilities. Forty-five healthy males matched for age and sex were included as a control group. In both groups, the degree of autistic tendencies was evaluated using the Autism-Spectrum Quotient (AQ). Using eight standard emotional expressions of Japanese people, two expression recognition tasks were set. An NIRS was used to measure the prefrontal cortex blood mobilization during the expression-processing process. The AQ was significantly higher in the ASD group, while the rate of overall correct expression response was significantly lower (p &rho;= &minus;0.40 p < 0.001). In the automatic expression-processing task, no activation in the prefrontal cortex was found in either the ASD or the control group. In the conscious expression-processing task, the activation of the left and right lateral prefrontal cortex was weaker in the ASD group compared to the control group. Unlike in the control group, a mild activation of posterior prefrontal cortex was found in the ASD group. The expression-processing process of the ASD group was found to be different from that of the control group. NIRS was effective in detecting a brain function disorder in people with ASD during an expression-processing process.

Identifying Gas-Washing and Water-Washing of Oil Reservoirs by Fluorescence and Infrared Spectra of Single Oil Inclusion

Samples in the two oil fields with reported gas-washing and water-washing were collected for fluid inclusion analysis.Micro-fluorescence and Fourier infrared spectra of single oil inclusions were measured to study the different effects of gas-washing and water-washing on oil compositions.The results show that spectral parameter QF_(535)values of the oils altered by gas-washing were expanded toward decreasing and increasing,respectively.The CH_(2)/CH_(3)distribution range ratio does not expand significantly,but the peak values are averaged.And the distribution of H_(2)O/Alkanes has no change.The QF_(535)values of the oils affected by water-washing increased towards the increase direction,and the distribution ranges of both CH_(2)/CH_(3)and H_(2)O/Alkanes increase significantly.The changes of QF_(535)in light oil reservoirs altered by gas-washing and CH_(2)/CH_(3)in heavy oil reservoirs by water-washing are not obvious.Therefore,two spectral parameter distribution trend charts of light and heavy oil reservoirs are summarized to discriminate the gas-washing and water-washing processes.This study is of great practical significance to utilize fluid inclusion analysis to restructure stages and processes of petroleum accumulation.

Detection of Chlorpyrifos Residues in Akesu Red Fuji Apple based on Near Infrared Spectrum

[Objective] The paper was to explore a method for detecting chlorpyrifos residues in red Fuji apple. [Method] The original spectral data of apple samples sprayed with different volume fractions of chlorpyrifos were collected using near infrared spectrometer at the band of 4 000-10 000 cm^（-1）. The original spectra were pre-treated by a variety of methods, and partial least squares（PLS） model was established for predictive analysis. [Result] Near infrared spectrum showed sensitivity to apple samples sprayed with different volume fractions of chlorpyrifos, but had low precision on pesticide-free samples. Data of blank control group were further eliminated for modeling prediction. The results showed that the results were the best when pre-treated with first derivative（FD）： R=0.987 9; the square error of prediction（SEP） was 0.173 6; the root-mean-square error of cross-validation（RMSECV） was 0.120 5; and the precision was 0.923 4. [Conclusion] Near infrared spectrum can better predict chlorpyrifos residue, providing a new method for detecting chlorpyrifos residues in Akesu red Fuji apple.

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.

Ca^(2+)影响辛基异羟肟酸浮选独居石的FTIR、XPS研究

独居石浮选体系中往往有方解石、萤石、白云石等大量的伴生矿,而这些伴生矿在独居石矿中会解离出大量的Ca^(2+),而Ca^(2+)往往会影响矿浆浮选环境。为此,通过Ca^(2+)的溶液化学计算、独居石浮选试验,以及浮选条件下作用的独居石表面红外光谱分析(FTIR)和X射线光电子能谱(XPS),分析研究Ca^(2+)的影响。Ca^(2+)的溶液化学计算显示,在水溶液中,随着pH值的升高,Ca^(2+)分别以离子态、羟基络合物和氢氧化合物的形式存在,当pH值在7~8之间,优势组分为Ca^(2+)和Ca(OH)^(+)。独居石浮选结果表明,不添加Ca^(2+)时,捕收剂OHA不能充分的浮选独居石,回收率为75.37%;而在pH为8±0.5,加入3×10^(-4)mol·L^(-1)的Ca^(2+)剂量,可显著的提高OHA对独居石的浮选性能,回收率达到96.48%。由溶液化学计算可知,Ca(OH)+是活化独居石的优势组分;Ca^(2+)剂量大于3×10^(-4)mol·L^(-1)时浮选回收率下降幅度较大,说明Ca^(2+)剂量的进一步增加,反而抑制独居石浮选,只有一定剂量的Ca^(2+)有效的促进独居石浮选,这可能归因于Ca^(2+)剂量消耗了OHA的浓度,进而影响独居石的浮选。红外光谱分析表明,在Ca^(2+)的作用下,光谱中出现两个关键性的新峰,其一为1454 cm^(-1)处的N—O—H弯曲振动峰,其二为880 cm^(-1)处的O—N拉伸振动峰,而在2974和2928 cm^(-1)的有机峰—CH_(3)和—CH_(2)—峰明显增强,这些基团的出现表明发生了化学吸附且吸附强度大于纯独居石吸附OHA的效果。XPS分析表明,仅使用OHA吸附独居石,独居石表面的N元素相对含量较低,为0.61%,而Ca^(2+)处理后的独居石,OHA吸附独居石时,独居石表面的N元素相对含量较高,达到2.36,由此可以得出,Ca^(2+)会促进OHA吸附到独居石表面。从分峰拟合中可以看出,添加Ca^(2+)在独居石的解理面上氧原子与Ca(OH)^(+)反应形成O—Ca—OH基团,可以作为吸附OHA的新吸附位点,同时独居石的铈原子与OHA上的两个氧原子形成五元螯合物也作吸附位点,得出独居石表面可以有两个吸附位点,独居石表面的Ca和Ce原子的活性位点都能吸附OHA,有利于OHA在独居石表面吸附,形成更均匀更致密的OHA疏水吸附层,这就是Ca^(2+)在OHA浮选独居石的性能得到改善的原因。这项研究有助于丰富矿浆中金属离子的活化理论,也证实了有效的矿物浮选分离不仅仅依赖于捕收剂-矿物相互作用的强度,而在很大程度上依赖于浮选溶液的化学性质。利用或者控制表面反应是开发一种更高效、更经济的浮选工艺的主要技术手段。

Preparation of Ultrafine SiO2 Powder from Rice Husk and Properties of Its Infrared Spectrum

This paper discussed impact of temperature on the size distribution in preparing ultrafine silica from rice husk.The samples prepared were analyzed with infrared spectrum,and the relation between the particle size and intensity of characteristic absorption peak of IR at center around 1 100 cm-1 was disscussed with the baseline method.Results show that when the temperature is 650 ℃ and roasting time is 11 h,at optimal reaction conditions,the size distribution of the ultrafine silica powder prepared is relatively concentrated,and the average particle size is 199.5 nm.Moreover,the characteristic absorption band of IR is broadening gradually along with particle size decreasing.

Study on the Authenticity of Identification Methods in White Spirit by Infrared Spectrometer

This experiment studies on the used infrared spectroscopy to establish technology methods for liquor identification methods, as well as offers the science data for establishment of the fingerprint in white spirit. The results have shown that using near-infrared spectroscopy analysis of liquor has the obvious features such as strong specificity, good reproducibility, simple operation, and finally confirmed that it is an authentic and ideal method for identification in white spirit.

ANALYSIS OF SYMMETRY OF C_60) ADSORBED ON THE SILVER MIRROR BY SERS SPECTRUM

The SERS spectrum of C_(60) was obtained by using silver mirror. From the SERS spectrum of C_(60) and the IR spectrum of C_(60), we proposed that C_(60) adsorbed on the silver mirror adopts a more ellipsoidal shape.

新吲哚菁绿IR-820辅助的近红外荧光成像和光热及协同治疗在肿瘤诊疗中的应用进展

新吲哚菁绿IR-820因其具有强近红外(near-infrared,NIR,750~1700 nm)荧光特性、良好生物相容性、高光热转换效率及稳定性等优势,在NIR发光的有机荧光染料中脱颖而出,被广泛应用于生物医学成像、荧光标记、细胞实时监测、光热治疗等研究领域。为更好地发挥IR-820的生物医学应用价值,研究人员用不同生物化学分子修饰IR-820来增强其荧光及光热特性,制备多种类的荧光纳米粒子,在基础生物医学成像与肿瘤光热治疗方面开展了众多研究。总结了IR-820荧光纳米粒子在近红外荧光成像和通过光热机理及与其他技术协同治疗肿瘤中的应用研究,希望为进一步推进有机荧光染料IR-820在生物医学领域应用和临床转化发展提供参考。

Signature of symmetry of laterally coupled quantum dots in far-infrared spectrum

We study the effect of structure asymmetry on the energy spectrum and the far-infrared spectrum （FIR） of a lateral coupled quantum dot. The calculated spectrum shows that the parity break of coupled quantum dot results in more coherent superpositions in the low-lying states and exhibits unique anti-crossing in the two-electron FIR spectrum modulated by a magnetic field. We also find that the Coulomb correlation effect can make the FIR spectrum of coupled quantum dot without strict parity deviate greatly from Kohn theorem, which is just contrary to the symmetric case. Our results therefore suggest that FIR spectrum may be used to determine the symmetry of coupled quantum dot and to evaluate the degree of Coulomb interaction.

环保绝缘介质C_(6)F_(12)O混合气体FTIR检测技术研究

环保绝缘介质C_(6)F_(12)O混合气体具有应用于中低压设备的潜力,因此C_(6)F_(12)O混合气体检测技术的研究具有非常重要的现实意义。文中基于红外吸收光谱提出了C_(6)F_(12)O混合气体定性定量检测技术。基于密度泛函理论,对C_(6)F_(12)O分子进行结构优化,仿真计算其振动频谱,与实验检测红外光谱进行对比。对体积分数标定模型的波段和特征量的选取进行了详细的研究,提出C_(6)F_(12)O混合气体相关绝缘设备的混合比和微量体积分数检测方案。结果表明,红外光谱的仿真结果与实验结果具有较好的一致性;不同体积分数的吸收峰有很好的线性关系,利用峰值作为特征值比峰面积建立的体积分数标定模型准确性和稳定性强。混合比检测时,以3 500~3 567 cm^(-1)波段的峰值作特征量建立模型的拟合度为0.999 57,检测误差在2%以内;微量检测时,以1 750~1 820 cm^(-1)波段的峰值作特征量建立模型的拟合度高达0.999 97,检测误差小于3.8%,建立的体积分数标定模型的稳定性、准确性较好。文中研究结果提供实验和仿真的C_(6)F_(12)O红外光谱信息,为C_(6)F_(12)O型气体绝缘设备提供FTIR检测技术,为C_(6)F_(12)O混合气体绝缘设备的混合比和微量体积分数检测提供了重要的理论支撑。

Airborne Shortwave Infrared Spectral Remote Sensing as a Direct Prospecting Method for Oil and Gas Resources

The spectral characters of hydrocarbons in some oil-bearing strata and soil layers over oil and gas reservoirs in the Junggar Basin and northern Tarim Basin in Xinjiang are compared with those of chemically pure hydrocarbons. The hydrocarbons are characterized by the bi-absorption at 2310nm and 2350nm. Hydrocarbon and radioactive anomalies in oil and gas terrains are found much more widespread than carbonate altcrations. Based on the spectra of heavy hydrocarbons related to oil between 2270nm and 2460nm and refined data treatme nt, remote sensing may hold encouraging promise as a directly prospecting technique for oil and gas resources.

Extraction of the key infrared radiation temperature features concerning stress and crack evolution of loaded rocks

The infrared radiation temperature(IRT)variation concerning stress and crack evolution of rocks is a critical focus in rock mechanics domain and engineering disaster warning.In this paper,a methodology to extract the key IRT features related to stress and crack evolution of loaded rocks is proposed.Specifically,the wavelet denoising and reconstruction in thermal image sequence(WDRTIS)method is employed to eliminate temporal noise in thermal image sequences.Subsequently,the adaptive partition temperature drift correction(APTDC)method is introduced to alleviate temperature drift.On this basis,the spatial noise correction method based on threshold segmentation and adaptive median filtering(OTSU-AMF)is proposed to extract the key IRT features associated with microcracks of loaded rocks.Following temperature drift correction,IRT provides an estimation of the thermoelastic factor in rocks,typically around 5.29×10^(-5) MPa^(-1) for sandstones.Results reveal that the high-temperature concentrated region in cumulative thermal images of crack evolution(TICE)can elucidate the spatiotemporal evolution of localized damage.Additionally,heat dissipation of crack evolution(HDCE)acquired from TICE quantifies the progressive failure process of rocks.The proposed methodology enhances the reliability of IRT monitoring results and provides an innovative approach for conducting research in rock mechanics and monitoring engineering disasters.