Synthesis of poly(3,4-propylenedioxythiophene)/MnO2 composites and their applications in the adsorptive removal of methylene blue

AbstractThe poly(3,4-propylenedioxythiophene)/MnO2 composites (PProDOT/MnO2) were prepared successfully by soaking the PProDOT powders into potassium permanganate (KMnO4) solution, with the mass ratio of PProDOT and KMnO4 from 2:1 to 1:2. The structure and morphology of composites were characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, ultraviolet–visible absorption spectra (UV), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX) and field emission scanning electron microscope (FE-SEM). Furthermore, PProDOT/MnO2 composites were tested as the adsorbents for removal of methylene blue (MB) from aqueous solution. The results revealed that the composites were successfully synthesized, and the thiophene sulfur was oxidized into sulfoxide by KMnO4. The highest percentage removal of MB after 30min was 91% for PProDOT/MnO2 (1:2) composite, and the percentage removal of MB was ~12mgg−1 after 60min at initial concentrations of MB dye of 5.6mgL−1 in the case of PProDOT/MnO2 (1:2) composite. Besides, the adsorption process of PProDOT/MnO2 (1:2) composite was described by pseudo-second-order and Langmuir models

Signal Improvement for Underwater LIBS

We employed a collinear long-short double-pulse laser induced breakdown spectroscopy (LS-DP-LIBS) to detect the underwater metal samples. The emission spectra, time-resolved signal, plasma images and sound characteristics of plasma shockwaves are experimentally investigated in this work. The results show that the underwater signal of Al, Cu and Fe spectral lines are significantly improved by collinear LS-DP-LIBS with inter-pulse delay of 35 us. The mechanism of the signal improvement is considered to be the pre irradiation effect of the long pulse laser beam. In the collinear LS-DP-LIBS method, the long pulse first generates a cavitation bubble in water and provides a gaseous environment. Then the short pulse generates the plasma from the sample surface. The present experiments show that the collinear LS-DP-LIBS method offers a significant signal improvement in underwater measurement of metal samples. This new method has great potential in deep-sea exploration using LIBS

Improved Analysis of Manganese in Steel Samples Using Collinear Long–Short Double Pulse Laser-Induced Breakdown Spectroscopy (LIBS)

A long-short double pulse laser-induced breakdown spectroscopy (long-short DP-LIBS) method was employed to improve the performance of LIBS for the measurement of manganese in steel samples. The long pulse was generated by a Nd:YAG laser which was operated at free runing (FR) mode. To investigate the detection ability without sample preparation, the steel washers were tested using SP-LIBS and long-short DP-LIBS, respectively. The measurement results show that the long-short DP-LIBS method was able to record clear spectra from the rusty steel washers. The steel washers were also measured after the polishing process. The measurement results show that the signal intensity was enhanced by long-short DP-LIBS. Through the observation with scanning electron microscope (SEM) on the laser craters, the results suggest that the improvement of detection ability can be attributed to the pre-radiation effect of long-pulse laser beam. Next, the analytical performance for quantitative measurement of manganese was evaluated by employing ten standard steel samples. The results show that the linearty fit (R2) of calibration curve is 0.988 for long-short DP-LIBS, whereas, R2 is only 0.810 for SP-LIBS under the same measurement conditions. The five times repeated measurement results show that the average Relative Standard Deviation (RSD) of the tested samples is 29.3% for SP-LIBS and is 10.5% for long-short DP-LIBS. The prediction results also show that the average Relative Error of Prediction (REP) is 94.9% for SP-LIBS and it 4.9% for long-short DP-LIBS. The experimental results in current work demonstrate that long-short DP-LIBS is promising for the on line measurement of steel in the steelmaking plant

Feasibility Investigation for Online Elemental Monitoring of Iron and Steel Manufacturing Processes using Laser-Induced Breakdown Spectroscopy

The metallurgical industries are very important for social development. In order to improve the metallurgical techniques and quality of products, the real-time analysis and monitoring of iron and steel manufacturing processes are very significant. Laser-induced breakdown spectroscopy (LIBS) has been studied and applied for the contents measurement of iron and steel. In this paper, the remote open-path LIBS measurement was studied under different sample temperature, lens to target distance (LTD), sample angle conditions to clarify its online measurement features. The 3D profile measurement system of parallel laser beam fringes projection was also developed to measure the sample profile at different sample temperature. The measurement results demonstrated the robustness of remote open-path LIBS system and 3D profile measurement system. However, the correction is necessary to enhance the detection ability of LIBS online measurement. In order to improve the precision and accuracy of real-time elemental measurement, an innovative co-axial laser beam measurement system combining LIBS and 3D profile techniques is proposed to automatically adjust the focus unit and measure the sample components. The further study of this promising method will be developed for online application of iron and steel manufacturing processes

Structured sparse model based feature selection and classification for hyperspectral imagery

Sparse modeling is a powerful framework for data analysis and processing. It is especially useful for high-dimensional regression and classification problems in which a large num-ber of feature variables exist but the amount of training sam-ples is limited. In this paper, we address the problems of feature description, feature selection and classifier design for hyperspectral images using structured sparse models. A lin-ear sparse logistic regression model is proposed to combine feature selection and pixel classification into a regularized op-timization problem with the constraint of sparsity. To explore the structured features, three-dimensional discrete wavelet transform (3D-DWT) is employed, which processes the hy-perspectral data cube as a whole tensor instead of adapting the data to a vector or matrix. This allows more effective capturing of the spatial and spectral structure. The structure of the 3D-DWT features is imposed on the sparse model by group LASSO which selects the features on the group level. The advantages of our method are validated on the real hyperspectral data

Viral pancreatitis: research advances and mechanisms

Acute pancreatitis is caused by trypsinogen activation in acinar cells caused by various injury forms (gallstone, high triglycerides, alcohol, etc.). Viral pancreatitis is a clinically rare disease type, which is easily neglected by clinicians and causes serious adverse consequences. Viral pancreatitis involves the entry of viruses into pancreatic cells, triggering inflammation, immune response activation, and enzymatic autodigestion, leading to tissue damage and potential complications. At present, there are few available reports on viral pancreatitis, most of which are case reports. This review brings attention to clinicians by describing the incidence of viral pancreatitis to enhance clinical understanding and patient care

Transient Receptor Potential Melastatin 8 (TRPM8)-Based Mechanisms Underlie Both the Cold Temperature-Induced Inflammatory Reactions and the Synergistic Effect of Cigarette Smoke in Human Bronchial Epithelial (16HBE) Cells

Transient receptor potential melastatin 8 (TRPM8) is a major receptor of cold environment. Recently, we found that cigarette smoke extract (CSE) upregulated TRPM8 mRNA and protein expression in bronchial tissues that made them more sensitive to cold stimuli. In our present study, we found that cold temperature (18°C)-induced activation of TRPM8 in 16HBE (human bronchial epithelial) cells facilitated Ca2+ influx and subsequently led to the increased expression of interleukin (IL)-6, IL-8, and tumor necrosis factor (TNF)-α via the upregulation of p-extracellular signal-regulated kinase (ERK) and the activation of NF-κB. In addition, 16HBE cells that co-stimulated with 18°C and CSE were used to explore the synergistic effect of CSE on cold temperature-induced inflammatory cytokine production as well as the possible involved signaling pathway. RT-PCR and western blot analysis revealed that CSE upregulated TRPM8 mRNA and protein level in 16HBE cells. Ca2+ imaging, western blot, and luciferase assay showed more robust increase in intracellular Ca2+ and promoted phosphorylated ERK, P38, and NF-κB activity, respectively, in 16HBE cells co-stimulated with CSE and cold temperature, and such alteration was attenuated by TRPM8 short hairpin RNA (shRNA) transfection and BCTC pretreatment. Furthermore, enhanced levels of IL-6, IL-8, and TNF-α showed by enzyme-linked immunosorbent assay (ELISA) were reduced by specific inhibitors of ERK and NF-κB. Collectively, our results suggest that mitogen-activated protein kinase (MAPK)/NF-κB signaling is involved in TRPM8-mediated cold temperature-induced inflammatory cytokine expression. In addition, CSE synergistically amplifies cold temperature-induced inflammatory factors release via upregulating TRPM8 expression and enhancing MAPK/NF-κB signaling pathway

Quantitative Elemental Analysis Using Long-Short Double-Pulse Laser Induced Breakdown Spectroscopy

鉄鋼プロセス，ボイラなどの様々な産業プロセスにおいて，物質の元素組成をリアルタイムで計測可能な技術が求められている．鉄鋼プロセスでは，鉄鉱石，コークス，石灰石などを原料として，鋼板などを製造する過程で各プロセス中の成分組成を計測することが求められ，溶融金属の組成などをリアルタイム制御することなどが重要となる．しかし，現在まで，これらの産業プロセスで元素組成をリアルタイムで計測可能な技術や装置は実用化されていない．レーザーを用いた非接触，リアルタイム計測方法として，レーザー誘起ブレークダウン分光法(Laser Induced Breakdown Spectroscopy，LIBS)がある．本研究では，LIBSを用いた元素組成の定量計測を目的に，ロング・ショートダブルパルスLIBSの開発を行った．本手法を鋼材中のマンガン及び炭素計測に適用し，計測の安定性，定量性に優れた特性を有することを実証した．The understanding of the controlling factors is becoming more important to improve the efficiency of industrial systems including steel-making processes, boilers and so on. Laser diagnostics such as laser-induced breakdown spectroscopy (LIBS) makes it possible to monitor these parameters due to their fast response, high sensitivity, and non-contact features. In this study, a new collinear long and short double pulse LIBS method was developed to improve the detection ability and the measurement accuracy by the control of the plasma cooling process using the long pulse-width laser radiation. The plasma generated by the short pulse-width laser is stabilized and maintained at high temperature during the plasma cooling process by long pulse-width laser radiation. The method was demonstrated to have better measurement stability and quantitative measurement characteristics for Manganese and Carbon measurement in the steel samples compared to the normal single pulse LIBS method

CURRENT DENSITY EFFECTS ON PLASMA EMISSION DURING PLASMA ELECTROLYTIC OXIDATION (PEO) ON AZ91D-MAGNESIUM ALLOY

The effect of bipolar pulse mode current ratio on plasma behavior was investigated in PEO on AZ91D Mg-Alloy. Two cases of current ratio including 1.20 and 0.88 were applied to the sample. Plasma emission behavior was studied using plasma images and plasma emission measured by photodetector and Intensified Charged-Couple Device (ICCD) camera. The current ratio of greater than 1 shows the continuous increase and then stabilization in emission intensity with a gradual increase in voltage throughout the PEO process. In contrast, the current ratio of less than 1, a sudden drop in plasma emission intensity with voltage was found after 786s. Therefore, PEO process can be divided into two regimes, arc regime and soft regime, before and after voltage drop respectively. Results of measured spectra show that a soft regime does not have atomic or ionic excitation during PEO process. It is demonstrated that the growth of porous layer during PEO can be controlled, which is benefit for the protective oxide coating of sample

Unveiling the additive-assisted oriented growth of perovskite crystallite for high performance light-emitting diodes.

Solution-processed metal halide perovskites have been recognized as one of the most promising semiconductors, with applications in light-emitting diodes (LEDs), solar cells and lasers. Various additives have been widely used in perovskite precursor solutions, aiming to improve the formed perovskite film quality through passivating defects and controlling the crystallinity. The additive's role of defect passivation has been intensively investigated, while a deep understanding of how additives influence the crystallization process of perovskites is lacking. Here, we reveal a general additive-assisted crystal formation pathway for FAPbI3 perovskite with vertical orientation, by tracking the chemical interaction in the precursor solution and crystallographic evolution during the film formation process. The resulting understanding motivates us to use a new additive with multi-functional groups, 2-(2-(2-Aminoethoxy)ethoxy)acetic acid, which can facilitate the orientated growth of perovskite and passivate defects, leading to perovskite layer with high crystallinity and low defect density and thereby record-high performance NIR perovskite LEDs (~800 nm emission peak, a peak external quantum efficiency of 22.2% with enhanced stability)