Recently, gas sensing is performed in various fields such as environmental protection, industrial process, agricultural analysis, medical care, and security and safety. In these fields, portable gas sensing apparatuses that enable high-sensitive, real-time, and/or on-site measurements are required. Figure 1 shows the correlation between the detection sensitivity and measurement time of existing...

Hydrogen-bond acidic polymers are important high affinity materials sensitive to organophosphates in the chemical warfare agent sensor detection process. Interactions between the sensor sensitive materials and chemical warfare agent simulants were studied by inverse gas chromatography. Hydrogen bonded acidic polymers, i.e., BSP3, were prepared for micro-packed columns to examine the interaction...

The NDIR gas detection method is based on the absorption of infrared radiation, which is shown by many polyatomic or heterodimer diatomic gases. For example CO2 gas absorbs IR radiation at 4.26μm wavelength. The detected radiation intensity at this wavelength decreases if the concentration of CO2 increases between source and detector. The extent of absorption mainly depends on the absolute numb...

At the present theoretical study, DFT calculations were performed for elucidating thereaction, absorption energy and the quantum molecular descriptors including electronic chemical potential, chemical hardness, Homo, Lumo, band gap energy (Eg) and finding the most active nitrogen-doped graphene sheet (N-G) for absorption H2S, CH4, N2 and CO2 gases. Finally it found that nitrogen-doped gra...

Gas Chromatography (GC) is a mature analytical technology used predominately for separating and quantifying the components of complex organic chemical mixtures. The addition of mass selective detectors has extended the use of GC to include compound identification. A wide range of columns and sample introduction techniques allow GC to solve most analytical problems for volatile and semi-volatile...

Membrane contactor using amine based absorbents is an efficient technology for CO2 separation from gaseous mixtures. A novel porous polysulfone (PSF) flat membrane was prepared via non-solvent phase inversion method. The PSF membrane was modified by adding polyvinyl pyrrolidone (PVP) to the dope solution. The fabricated membrane was used in the serpentine flow field contactor module for CO2 abs...

We present a new HST/STIS spectrum of the z = 3.18 quasar PKS 1935-692 and summarize the spectral features shortwards of 304 Å in the rest frame likely to be caused by foreground HeII Lyman-α absorption. In accord with previous results on two other quasars at similar redshifts, we demonstrate a correlation with the HI Lyman-α forest absorption, and show that much of the helium absorption is cau...

The LINER galaxy NGC 2639 contains a water vapor megamaser, suggesting the presence of an edge-on nuclear accretion disk or torus. This galaxy is thus a good candidate for revealing absorption by the torus of any compact nuclear continuum emission. In this paper, we report VLBA radio maps at three frequencies and an ASCA X-ray spectrum obtained to search for free-free and photoelectric absorpti...

Laboratory measurements of water vapor absorption using cavity ring-down spectroscopy revealed a broad absorption at 405 nm with a quadratic dependence on water monomer concentration, a similar absorption with a linear component at 532 nm, and only linear absorption at 570 nm in the vicinity of water monomer peaks. D2O ab5 sorption is weaker and linear at 405 nm. Van’t Hoff plots constructed at...

Low-temperature photoluminescence-excitation spectra are studied in an n-type modulation-doped T-shaped single quantum wire with a gate to tune electron densities. With a nondegenerate one-dimensional (1D) electron gas, the band-edge absorption exhibits a sharp peak structure induced by the 1D density of states. When the dense 1D electron gas is degenerate at a low temperature, we observe a Fer...