Chemical Vapor Deposition and Thermal Oxidation of Cuprous Phosphide Nanofilm

Inorganic semiconductors usually show n-type characterization; the development of p-type inorganic semiconductor material will provide more opportunities for novel devices. In this paper, we investigated the chemical vapor deposition (CVD) of p-type cuprous phosphide (Cu3P) nanofilm and studied its thermal oxidation behavior. Cu3P film was characterized by optical microscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), laser Raman spectroscopy (Raman), and fluorescence spectroscopy (PL). We found that the thickness of film ranged from 4 to 10 nm, and the film is unstable at temperatures higher than room temperature in air. We provide a way to prepare inorganic phosphide nanofilms. In addition, the possible thermal oxidation should be taken into consideration for practical application.

Multi-Analytical Research on the Caisson Painting of Dayu Temple in Hancheng, Shaanxi, China

In this research, the caisson painting of Dayu Temple in Hancheng, Shaanxi, China, was analyzed via a multi-analytical methodology, using a pH meter, an ultra-depth-of-field optical microscope, a scanning electron microscope–energy dispersive spectrometer (SEM-EDS), a high-resolution X-ray diffractometer (XRD), a micro-confocal laser Raman spectrometer, a gas chromatography mass spectrometer (GC-MS), and X-ray fluorescence spectroscopy (XRF). With the corroborative evidence derived from the above analyses, it could be determined that the caisson painting of Dayu Temple was painted on bamboo paper and attached to hemlock wood substrate of the Pinaceae Tsuga genus using starch paste, with common colorants such as carbon black, cinnabar mixed with a small amount of red lead, ultramarine, and ultramarine mixed with Paris green, with animal glue having been adopted as a sizing agent. These results provide important scientific data for the production craft of precious caisson paintings, contributing to the revelation of their historic, artistic, and scientific value, and should enable conservators to make informed decisions in restoration.

Synergistic Flame-Retardant Effect of Aluminum Diethyl Phosphinate in PP/IFR System and the Flame-Retardant Mechanism

Synergistic flame-retardant effect of aluminum diethyl phosphinate (AlPi) in intumescent flame retardant polypropylene (PP/IFR) system and the flame-retardant mechanism were investigated. The flame retardancy of PP/IFR/AlPi (the mass ratio of IFR to AlPi is 2 : 1) was the best, which was proved by the results of the limiting oxygen index (LOI) test, UL-94 test, and cone calorimeter test ( CCT) test. Here, the LOI value of the sample was as high as 34% and passed the V–0 rating in UL–94 test. The peak heat release rate (PHRR) decreased by 92.57%, the total heat release (THR) reduced by 90.52%. Thermogravimetric (TGA) data showed that the introduction of AlPi improved thermal stability and changed the thermal degradation behavior of PP/IFR composites. Interestingly, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDXS) and laser Raman spectroscopy (LRS) proved that PP/IFR/AlPi had formed more residual carbon, but the flame retardancy was worse than PP/IFR/AlPi. This is because when the mass ratio of IFR to AlPi is 2 : 1, the synergy between IFR and AlPi was significant, gas-phase flame retardant and condensed-phase flame retardant reached a balance and obtained the best flame retardant effect.

Structural Changes of Hydroxylapatite during Plasma Spraying: Raman and NMR Spectroscopy Results

Functional osseoconductive coatings based on hydroxylapatite (HAp) and applied preferentially by atmospheric plasma spraying to medical implant surfaces are a mainstay of modern implantology. During contact with the hot plasma jet, HAp particles melt incongruently and undergo complex dehydration and decomposition reactions that alter their phase composition and crystallographic symmetry, and thus, the physical and biological properties of the coatings. Surface analytical methods such as laser-Raman and nuclear magnetic resonance (NMR) spectroscopies are useful tools to assess the structural changes of HAp imposed by heat treatment during their flight along the hot plasma jet. In this contribution, the controversial information is highlighted on the existence or non-existence of oxyapatite, i.e., fully dehydrated HAp as a thermodynamically stable compound.

The structural spectra of high dilutions and their unconventional application

Until few years, the so-called implausible science, homeopathy, was on the verge of being rejected on conventional physicochemical grounds. The mere selection of ultrahigh dilutions (UHD) (homeopathic potencies) for experimentation by mainstream scientists seemed impossible, but the curiosity to explore the science behind homeopathy kept igniting intellectual alma mater who subjected homeopathy to laboratories and test tubes, to know beyond its clinical application. Still, there exist a huge gap and a challenge to convince a conventional scientist to go beyond his domains and look for something which is apparently invisible (beyond Avogadro). But gradually we are overcoming this dogma and exploring the finer aspects and applications of UHDs. Much research has been undertaken, at least, to protect the identity of UHDs, and we are now verge of proving the plausibility of homeopathy from every aspect. This issue of International Journal of High Dilution Research features two interesting articles on nature of UHDs and their unconventional application. The first article by NC Sukul et al aimed to decipher the nature of the water structure of UHDs of two commonly used homeopathic drugs Natrum muriaticum and Sulphur by Laser Raman Spectroscopy. This work is in the series undertaken by the group, who earlier experimented using Nuclear Magnetic Resonance; Electronic, Vibrational and Raman spectroscopy to shown differences in UHDs of various drugs. The present experiment could differentiate the intensities (potencies) of Nat-m and Sulph when compared to their controls, on the basis of hydrogen bond strength and free OH groups. The second article by Nandy et al proposes a new dimension to the application of UHD. In an interesting manner, the author used UHDs of Ferrum metallicum and Zincum oxidatum to improve the electrical properties of the electroactive Poly (vinylidene fluoride-hexafluoropropylene) (PVDF-HFP). The PVDF-HFP composite films were synthesized in their usual way, but an incorporation of Ferrum and Zinc-o could make the film as homeo-PVDF-composite. This enhancement of the electrical properties and are possibly due to the presence of nanoparticle, as hypothesized by the group. The nature and application of UHDs are promising but challenging areas, which can only be validated through extensive research and validation. The realm of UHDs is expanding, and the day is not far when plausibility of homeopathy would be proved from every aspect, but at the same time we should also keep the momentum of research at pace in clinical research too!

Raman spectroscopy reveals variation in free OH groups and hydrogen bond strength in ultrahigh dilutions

Objective: To decipher the nature of water structure in two ultrahigh diluted (UHD) homeopathic drugs by Laser Raman Spectroscopy. Method: Two homeopathic drugs Calcarea carbonica (Calc.) and Sepia officinalis (Sep.) in 8cH, 202cH, and 1002cH and their diluent medium 90% ethanol in 8cH and 202cH were used in the present study. Laser Raman spectra of all the samples were obtained in the wave number region of 2400 – 4200 cm-1. The intensity ratio at vibration frequencies between 3200 and 3420 (R1) and that between 3620 and 3420 (R2) were calculated for each UHD of the samples. Results: The spectra show a marked difference in intensities in the stretching vibrations of CH and OH groups of all the samples. R1 values for three UHDs of Calc. and Sep. show negative and positive relationships, respectively. In the case of R2 values, the relationship in three UHDs is 81002 for Calc., and 8> 202 < 1002 for Sep. In the case of control (ethanol UHDs) both R1 and R2 show a negative relationship. Conclusion: R1 denotes a relative number of OH groups with strong and weak hydrogen bonds. R2 indicates the relative number of OH groups with broken and weak H-bonds. Therefore, the UHDs of the two drugs and the control are different from each other with respect to hydrogen bond strength of OH groups and the number of free OH groups or non-hydrogen bonded water molecules.

Reduction of NOx by H2 on WOx-Promoted Pt/Al2O3/SiO2 Catalysts Under O2-Rich Conditions

This work addresses the reduction of NOx by H2 under O2-rich conditions using Al2O3/SiO2-supported Pt catalysts with different loads of WOx promotor. The samples were thoroughly characterised by N2 physisorption, temperature-programmed desorption of CO, scanning electron microscopy, X-ray diffraction, laser raman spectroscopy, X-ray photoelectron spectroscopy and diffuse reflectance infrared fourier transform spectroscopy with probe molecule CO. The catalytic studies of the samples without WOx showed pronounced NOx conversion below 200 °C, whereas highest efficiency was related to small Pt particles. The introduction of WOx provided increasing deNOx activity as well as N2 selectivity. This promoting effect was referred to an additional reaction path at the Pt-WOx/Al2O3/SiO2 interface, whereas an electronic activation of Pt by strong metal support interaction was excluded. Graphic Abstract