The Surface Morphologies and Spectroscopy Analysis of VC Coatings on the Substrate of Cr12MoV Prepared by TD Process after Salt Spray

The normal temperature corrosion of VC coating on the substrate of Cr12MoV prepared by TD process was tested in 5% NaCl aqueous solution, its surface morphologies and corrosion components after salt spray were observed with SEM and EDS, respectively, and the effects of salt spray on micro-structures of VC coating were analyzed. Moreover, the invalidation mechanism of VC coating after salt spray and its effect on substrate material were discussed. The experimental results shown that the uniformity and integrity of VC coating surface are destroyed by salt spray for 120 h, a large number of the pits are produced on the coating surface, and the coating falls off, which speeds corrosion breakage of its substrate; the oxidated film on its surface becomes rougher, broken and discontinuous, and falls off easily, which reduce the ability of resistance salt spray; the failure modes of VC coating after salt spray are expressed with falling off of oxidated film, stress concentration and pore effect and so on, the corrosion breakage of oxidated film is the corrosion result of deoxidization corrosion from oxygen and HCl produced by NaCl and vapor.

Combined spatial frequency spectroscopy analysis with visible resonance Raman for optical biopsy of human brain metastases of lung cancers

The purpose of this study is to examine optical spatial frequency spectroscopy analysis(SFSA)combined with visible resonance Raman(VRR)spectroscopic method,for thefirst time,to discriminate human brain metastases of lung cancers adenocarcinoma(ADC)and squamous cell carcinoma(SCC)from normal tissues.A total of 31 label-free micrographic images of three type of brain tissues were obtained using a confocal micro-Raman spectroscopic system.VRR spectra of the corresponding samples were synchronously collected using excitation wavelength of 532 nm from the same sites of the tissues.Using SFSA method,the difference in the randomness of spatial frequency structures in the micrograph images was analyzed using Gaussian functionfitting.The standard deviations,calculated from the spatial frequencies of the micrograph images were then analyzed using support vector machine(SVM)classifier.The key VRR biomolecularfingerprints of carotenoids,tryptophan,amide II,lipids and proteins(methylene/methyl groups)were also analyzed using SVM classifier.All three types of brain tissues were identified with high accuracy in the two approaches with high correlation.The results show that SFSA–VRR can potentially be a dual-modal method to provide new criteria for identifying the three types of human brain tissues,which are on-site,real-time and label-free and may improve the accuracy of brain biopsy.

SpectraTr:A novel deep learning model for qualitative analysis of drug spectroscopy based on transformer structure

The drug supervision methods based on near-infrared spectroscopy analysis are heavily dependent on the chemometrics model which characterizes the relationship between spectral data and drug categories.The preliminary application of convolution neural network in spectral analysis demonstrates excellent end-to-end prediction ability,but it is sensitive to the hyper-parameters of the network.The transformer is a deep-learning model based on self-attention mechanism that compares convolutional neural networks(CNNs)in predictive performance and has an easy-todesign model structure.Hence,a novel calibration model named SpectraTr,based on the transformer structure,is proposed and used for the qualitative analysis of drug spectrum.The experimental results of seven classes of drug and 18 classes of drug show that the proposed SpectraTr model can automatically extract features from a huge number of spectra,is not dependent on pre-processing algorithms,and is insensitive to model hyperparameters.When the ratio of the training set to test set is 8:2,the prediction accuracy of the SpectraTr model reaches 100%and 99.52%,respectively,which outperforms PLS DA,SVM,SAE,and CNN.The model is also tested on a public drug data set,and achieved classification accuracy of 96.97%without preprocessing algorithm,which is 34.85%,28.28%,5.05%,and 2.73%higher than PLS DA,SVM,SAE,and CNN,respectively.The research shows that the SpectraTr model performs exceptionally well in spectral analysis and is expected to be a novel deep calibration model after Autoencoder networks(AEs)and CNN.

Hexavalent Chromium Cr (VI) Removal from Water by Mango Kernel Powder

Metal trace elements (MTE) are among the most harmful micropollutants of natural waters. Eliminating them helps improve the quality and safety of drinking water and protect human health. In this work, we used mango kernel powder (MKP) as bioadsorbent material for removal of Cr (VI) from water. Uv-visible spectroscopy was used to monitor and quantify Cr (VI) during processing using the Beer-Lambert formula. Some parameters such as pH, mango powder, mass and contact time were optimized to determine adsorption capacity and chromium removal rate. Adsorption kinetics, equilibrium, isotherms and thermodynamic parameters such as ΔG˚, ΔH˚, and ΔS˚, as well as FTIR were studied to better understand the Cr (VI) removal process by MKP. The adsorption capacity reached 94.87 mg/g, for an optimal contact time of 30 min at 298 K. The obtained results are in accordance with a pseudo-second order Freundlich adsorption isotherm model. Finally FTIR was used to monitor the evolution of absorption bands, while Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) were used to evaluate surface properties and morphology of the adsorbent.

Progress of Mid Infrared Spectroscopy in Soil Environment Research

Soil is the basis of agricultural and forestry production,and it is of great significance to obtain soil information efficiently and comprehensively for soil management.Due to the complexity of soil organic components,it is difficult to obtain the information of soil organic components comprehensively by traditional chemical analysis method.As a non-destructive,real-time and high-throughput analysis method,mid infrared spectroscopy(MIR)has the ability to obtain soil organic environmental information efficiently and accurately.It can provide a large number of basic data for soil environmental monitoring,digital mapping,agricultural and forestry production,and help to realize the real-time monitoring of soil environment and the informatization of agriculture and forestry.In this paper,the detection process of MIR obtaining soil environmental spectral information and processing methods of spectral data were briefly introduced,and the research progress on extraction and influencing factors of mid infrared spectrum characteristics of soil in recent years was reviewed.Moreover,the significance and future development direction of soil science for the technology were discussed.

Rapid Detection of Oil Pollution in Soil by Using Laser-Induced Breakdown Spectroscopy

Detection of oil pollution in soil has been carried out using laser-induced breakdown spectroscopy（LIBS）. A pulsed neodymium-doped yttrium aluminum garnet（Nd：YAG） laser（1,064 nm, 8 ns, 200 mJ） was focused onto pelletized soil samples. Emission spectra were obtained from oil-contaminated soil and clean soil. The contaminated soil had almost the same spectrum profile as the clean soil and contained the same major and minor elements. However, a C–H molecular band was clearly detected in the oil-contaminated soil, while no C–H band was detected in the clean soil. Linear calibration curve of the C–H molecular band was successfully made by using a soil sample containing various concentrations of oil. The limit of detection of the C–H band in the soil sample was 0.001 mL/g. Furthermore, the emission spectrum of the contaminated soil clearly displayed titanium（Ti） lines, which were not detected in the clean soil. The existence of the C–H band and Ti lines in oil-contaminated soil can be used to clearly distinguish contaminated soil from clean soil. For comparison, the emission spectra of contaminated and clean soil were also obtained using scanning electron microscope-energy dispersive X-ray（SEM/EDX） spectroscopy,showing that the spectra obtained using LIBS are much better than using SEM/EDX, as indicated by the signal to noise ratio（S/N ratio）.

Rapid recognition of Chinese herbal pieces of Areca catechu by different concocted processes using Fourier transform mid-infrared and near-infrared spectroscopy combined with partial least-squares discriminant analysis

Rapid and sensitive recognition of herbal pieces according to different concocted processing is crucial to quality control and pharmaceutical effect. Near-infrared （NIR） and mid-infrared （MIR） technology combined with supervised pattern recognition based on partial least-squares discriminant analysis （PLSDA） was attempted to classify and recognize six different concocted processing pieces of 600 Areca catechu L. samples and the influence of fingerprint information preprocessing methods on recognition performance was also investigated in this work. Recognition rates of 99.24%, 100% and 99.49% for original fingerprint, multiple scatter correct （MSC） fingerprint and second derivative （2nd derivative） fingerprint of NIR spectra were achieved by PLSDA models, respectively. Meanwhile, a perfect recognition rate of 100% was obtained for the above three fingerprint models of MIR spectra. In conclusion, PLSDA can rapidly and effectively extract otherness of fingerprint information from NIR and MIR spectra to identify different concocted herbal pieces ofA. catechu.

Influence of TiO_2 on the electrochemical performance of pasted typeβ-nickel hydroxide electrode in alkaline electrolyte

Nickel hydroxide was used as the positive electrode material in rechargeable alkaline batteries, which plays a significant role in the field of electric energy storage devices. β-nickel hydroxide（β-Ni（OH）2 ） was prepared from nickel sulphate solution using potassium hydroxide as a precipitating agent. Pure β-phase of nickel hydroxide was confirmed from XRD and FT-IR studies. The effects of TiO2 additive on the β-Ni（OH）2 electrode performance are examined. The structure and property of the TiO2 added β-Ni（OH）2 were characterized by XRD, TG-DTA and SEM analysis. A pasted–type electrode is prepared using nickel hydroxide powder as the main active material on a nickel sheet as a current collector. Cyclic voltammetry and electrochemical impedance spectroscopy studies were performed to evaluate the electrochemical performance of the β-Ni（OH）2 and TiO2 added β-Ni（OH）2 electrodes in 6 M KOH electrolyte. Anodic（Epa） and cathodic（Epc）peak potentials are found to decrease after the addition of TiO 2 into β-Ni（OH）2 electrode material. Further,addition of TiO2 is found to enhance the reversibility of the electrode reaction and also increase the separation of the oxidation current peak of the active material from the oxygen evolution current. Compared with pure β-Ni（OH）2 lectrode,TiO2 added β-Ni（OH）2 electrode is found to exhibit higher proton diffusion coefficient（D） and lower charge transfer resistance. These findings suggest that the TiO2 added β-Ni（OH）2 electrode possess improved electrochemical properties and thus can be recognized as a promising candidate for the battery electrode applications.

Design and analysis of Wedge-enhanced Raman spectroscopy substrate

Here,a novel Au Wedge-enhanced Raman spectroscopy(WERS)substrate is proposed.The electric field enhancement factor and the effective mode field radius with varying geometry parameters are investigated.The proper excitation wavelength 633 nm is obtained.The practical application of WERS substrate is discussed.The Au WERS not only can provide a continuous extremely highly localized electric field as surface-enhanced Raman scattering(SERS)hotspots,but also can offer 10 orders of magnitude of SERS enhancement factor.The corresponding results reveal that WERS substrate will be widely applied in optics,biology,chemistry and other fields.

Laser-induced breakdown spectroscopy in China

Laser-induced breakdown spectroscopy （LIBS） has been regarded as a future superstar for chemical analysis for years due to its unique features such as little or no sample preparation, remote sensing, and fast and multi-element analysis. Chinese LIBS comnmnity is one of the most dynamically developing communities in the World. The aim of the work is to inspect what have been done in China for LIBS development and, based on the understanding of the overall status, to identify the challenges and opportunities for the future development. In this paper, the scientific contributions from Chinese LIBS comlnunity are reviewed for the following four aspects： fimdamentals, instrumentation, data processing and modeling, and applications; and the driving force of LIBS development in China is analyzed, the critical issues for successful LIBS application are discussed, and in our opinion, the potential direction to improve the technology and to realize large scale commercialization in China is proposed.

Multi-element analysis by ArF laser excited atomic fluorescence of laser ablated plumes： Mechanism and applications

A new multi-element analysis technique based on laser-excited atomic fluorescence was reviewed. However, the one-wavelength-one-transition constraint was overcome. Numerous elements were induced to fluoresce at a single excitation wavelength of 193 nm. This was possible provided that the analytes were imbedded in dense plumes, such as those produced by pulsed laser ablation. The underlying mechanism of the technique was explained and corroborated. Analytical applications to metals, plastics, ceramics and their composites were discribed. Detection limits in the ng/g range and mass limits of atto moles were demonstrated. Several real-world problems, including the analysis of paint coating for trace lead, the non-destructive analysis of potteries and ink, the chemical profiling of electrode plastic interfaces, and the analysis of ingestible lead colloids were discussed.

Phytochemical Estimation and Therapeutic Amelioration of Aesculus hippocastanum L. Seeds Ethanolic Extract in Gastric Ulcer in Rats Possibly by Inhibiting Prostaglandin Synthesis

Objective To quantify phytochemicals using liquid chromatography and mass spectroscopy(LCMS)analysis and explore the therapeutic effect of Aesculus hippocastanum L.(AH)seeds ethanolic extract against gastric ulcers in rats.Methods Preliminary phytochemical testing and LCMS analysis were performed according to standard methods.For treatment,the animals were divided into 7 groups including normal control,ulcer control,self-healing,AH seeds low and high doses,ranitidine and per se groups.Rats were orally administered with 10 mg/kg of indomethacin,excluding the normal control group(which received 1%carboxy methyl cellulose)and the per se group(received 200 mg/kg AH seeds extract).The test group rats were then given 2 doses of AH seeds extract(100 and 200 mg/kg,respectively),while the standard group was given ranitidine(50 mg/kg).On the 11th day,rats in all groups were sacrificed,and their stomach was isolated to calculate the ulcer index,and other parameters such as blood prostaglandin(PGE2),tissue superoxide dismutase(SOD),catalase(CAT),malonyldialdehyde(MDA),and glutathione(GSH).All isolated stomach tissues were analyzed for histopathological findings.Results The phytochemical examination shows that the AH seeds contain alkaloids,flavonoids,saponins,phenolic components,and glycosides.LCMS analysis confirms the presence of quercetin and rutin.The AH seeds extract showed significant improvement in gastric mucosa conditions after indomethacin-induced gastric lesions(P<0.01).Further marked improvement in blood PGE2 and antioxidant enzymes,SOD,CAT,MDA and GSH,were observed compared with self-healing and untreated ulcer-induced groups(P<0.01).Histopathology results confirmed that AH seeds extract improved the mucosal layer and gastric epithelial membrane in treated groups compared to untreated ulcer-induced groups.Conclusions LCMS report confirms the presence of quercetin and rutin in AH seeds ethanolic extract.The therapeutic effect of AH seeds extract against indomethacin-induced ulcer in rat model indicated the regenerated membrane integrity,with improved cellular functions and mucus thickness.Further,improved antioxidant enzyme level would help to reduce PGE2 biosynthesis.

The d-orbital coupling modulation of CuNi alloy for acetonitrile electrochemical reduction and in-situ hydrogenation behavior characterization

Electrochemical reduction of acetonitrile to ethylamine with a high selectivity is a novel approach to manufacture valuable primary amines which are important raw material in organic chemical industry. However, the poor ethylamine Faradic efficiency(FE_(ethylamine)) and catalyst stability at the high current density prohibit this method from being practically used. Herein, CuNi alloy ultrafine-nano-particles based on the d-orbital coupling modulation were synthesized through the electrodeposition and their catalytic performance towards acetonitrile reduction reaction(ACNRR) has been systematically studied. The highest FE_(ethylamine)(97%) is achieved with the current density of-114 mA cm^(-2). For practical application, the current density can reach-602.8 mA cm^(-2) with 82.8% FE_(ethylamine)maintained. With the appearance of other organics which co-exist with acetonitrile in the SOHIO process, CuNi can also hydrogenate acetonitrile in it with more than 80% FE_(ethylamine). Our in-situ spectroscopy analysis and DFT calculations towards the acetonitrile hydrogenation behavior reveal that the evenly dispersed Ni in Cu modulates the dband so as to endow CuNi with the better acetonitrile adsorption, milder binding energy with the reaction intermediates, smaller barrier for *CH_3CH_2NH_2 desorption and higher ability for H_2O dissociation to provide *H.