Highly enhanced UV absorption and light emission of monolayer WS_(2)through hybridization with Ti_(2)N MXene quantum dots and g-C_(3)N_(4)quantum dots

Two-dimensional(2D)transition metal dichalcogenides(TMD)are atomically thin semiconductors with promising optoelectronic applications across the visible spectrum.However,their intrinsically weak light absorption and the low photoluminescence quantum yield(PLQY)restrict their performance and potential use,especially in ultraviolet(UV)wavelength light ranges.Quantum dots(QD)derived from 2D materials(2D/QD)provide efficient light absorption and emission of which energy can be tuned for desirable light wavelength.In this study,we greatly enhanced the photon absorption and PLQY of monolayer(1L)tungsten disulfide(WS_(2))in the UV range via hybridization with 2D/QD,particularly titanium nitride MXene QD(Ti_(2)N MQD)and graphitic carbon nitride QD(GCNQD).With the hybridization of MQD or GCNQD,1LWS_(2)showed a maximum PL enhancement by 15 times with 300 nm wavelength excitation,while no noticeable enhancement was observed when the excitation photon energy was less than the bandgap of the QD,indicating that UV absorption by the QD played a crucial role in enhancing the light emission of 1L-WS_(2)in our 0D/2D hybrid system.Our findings present a convenient method for enhancing the photo-response of 1L-WS_(2)to UV light and offer exciting possibilities for harvesting UV energy using 1L-TMD.

The UV Aging Properties of Maleic Anhydride Esterified Starch/Polylactic Acid Composites

Esterified starch/polylactic acid（ES/PLA） blending composite was prepared by melting extrusion with maleic anhydride esterified starch and PLA as the raw materials. The composite was accelerated aging by using UV aging box, and its properties were characterized by Fourier transform infrared spectroscopy（FT-IR）, scanning electron microscopy（SEM）, X-ray diffraction（XRD）, thermo gravimetric analysis（TGA） and mechanical testing machine. FT-IR and SEM results show that the infrared absorption peak intensities of C-O, C-H, and C=O in aged samples decrease gradually with increasing aging time. The damage degree of surface and internal of aged samples increases gradually. XRD analysis results show that after aging treatment, the crystalline diffraction peak of thermoplastic esterified starch at 2θ = 21° disappears and the diffraction peaks of PLA at 2θ = 16.5° appear, indicating that the hydrolysis rate of esterified starch is greater than that of PLA. The crystallinity of PLA in aged sample shows an increasing trend at first followed by a decreasing one along with the increasing time of aging treatment, suggesting that the hydrolysis of amorphous regions of PLA is more preferential than its crystalline regions. Because of the influence of crystal structure and the change of composition structure, the initial decomposition temperature of aging test specimen gradually increases with the extension of aging time. The maximum decomposition rate temperature and residual mass increases at first, and then decrease after the aging time extending to 1600 h. As the aging time increases, the damage degree of combination interface between esterification starch and PLA is exacerbated, resulting in the tensile strength and bending strength of aged specimen decreasing gradually.

Effect of Heat-treatment on Crystalline Phase and UV Absorption of 60CeO_2-40TiO_2 Thin Films by Magnetron Sputtering

60CeO2-40TiO2 thin films were deposited on soda-lime silicate glass substrates by R.F. magnetron sputtering. The effects of heat-treatment on the UV-absorption of the thin films were studied on the 60CeO2-40TiO2 thin film with the largest UV cut-off wavelength. The sample films with CeO2：TiO2=60：40 were heated at 773 K, 873 K, 973 K for 30 min. These films are characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and X-ray photoelectron spectroscopy and spectrometer （XPS）. XRD analysis proves that the addition of TiO2 to CeO2 changed the crystalline state of CeO2. But the UV absorption effect of CeO2-TiO2 films with CeO2 crystallite phase is inferior to that of the amorphous phase CeO2-TiO2 films. XPS analysis also indicates that the amorphous phase CeO2-TiO2 films have the most Ce3＋ content in these films. Amorphous phase and crystalline phase of the CeO2-TiO2 films have different effects on UV absorption of the thin films.

Estimation Approaches of ηUV,PUV and UV Directional Wave Spectra and Their Comparison

The observation and estimation of directional spectra of sea waves is one of the essential subjects of study of oceanic dynamics. On the basis of the irregular linear wave theory, estimation methods for i/UV, PUV and VV directional wave spectra are derived. By using ij and PUV data measured in-situ, directional wave spectra are estimated, meanwhile the virtues and defects of various spectra are comparied. This method provide a basis for the observations of sea waves.

Preparation of nanometer yellow iron and its UV absorption capacity

The nanometer yellow iron oxide was prepared by oxidizing Fe（OH）2 with air, which was verified with XRD and TEM. The result shows that nanometer yellow iron oxide is spindle-shaped and well-distributed with a long axis of 150-200 nm and short axis of 40-50 nm. Ultraviolet （UV） transmittance of the iron oxide shows the great effect of concentration on both transparency and UV ab- sorption, and it has been proven that iron oxide with a concentration of 0.025wt% is preferred. The spectrum of XRD indicates that it is goethite. When the yellow iron is dispersed in sol, given that the wavelength of UV is less than 300 nm, its UV absorption capacity is superior to those of ZnO and TiO2. The absorption capacity of the yellow iron is less than TiO2 and more than ZnO as the wavelength of UV is 300-400 nm.

Cell-cycle-dependent variation in UV absorption spectrum of Hela cells treated with Trichostatin A

Objective： The aim of our study was to discovery the different cell cycle arrest effect after different densities HeLa cells treated with Trichostatin A （TSA）. In addition, this study would find some important relationship between cycle arrest effect and UV absorption spectrum of cell. Methods： 0.2 IJM TSA was applied to act on HeLa cells of different density. Then, the cycle arrest effect and UV absorption spectrum of cells were investigated, which provide support to analyze the effect of TSA on cancer cells. Results： Cell cycle arrest effect in G0/G1 of the lower density cells was more obvious than that in other groups. The other discovery in this work was that the cellular UV absorption value was higher when the density of cultured cell was lower. Conclusion： This experiment would guide the clinical study on early or late stage cancer patients in the future. On the other hand, this work indicates when cells were arrested in G0/G1 phase, the cellular absorption value increased at the same time, so UV absorption spectrum could characterize the change of cell cycle.

Study of blood sugar concentration based on serum UV absorption spectra＊

UV absorption spectrum and neural network theory was used for the analysis of blood sugar concentration. Experimental investigation shows that absorption spectrum has the following characteristics in the wave band of 200-300 nm： （1） The absorption spectrum is of complex shape, there is more absorption peak in UV-band, it shows that there is a complex absorption phenomenon in blood group macromolecules; （2） The curve shapes of absorption spectra are similar to different samples ,the reason is that the spectrum is synthesis of some group macromolecules absorption spectrum; （3） There is a degree of displacement of absorption peak to different samples; （4） There is no significant correlation between absorbance and blood sugar concentration at 278 nm, but random. Based on the wave band of 280 nm to 300 nm, a neural network model was built to determine the blood sugar concentration.

Research on Viscoelasticity of Modifi ed Bitumen Containing LDHs Anti-UV Aging Agent

We applied LDHs to modify the bitumen by melt blending, and studied the viscoelasticity of LDHs modifi ed bitumen by means of dynamic shear rheometer（DSR）. The creep test was used to evaluate the viscoelastic behavior. The experimental results indicated that, due to the addition of the LDHs, the viscoelastic properties of modifi ed bitumen were superior to those of pristine bitumen. Therefore, the LDHs would be an alternative to modifi ers used in the bitumen to improve the UV-aging resistance during the service of asphalt pavement.

Development of an HPLC–UV assay method for the simultaneous quantification of nine antiretroviral agents in the plasma of HIV-infected patients

A new method using high-performance liquid chromatography coupled with ultra violet detection(HPLC–UV)was developed and validated for the simultaneous quantification of atazanavir,dolutegravir,darunavir,efavirenz,etravirine lopinavir,raltegravir,rilpivirine and tipranavir in human plasma.For the first time we reported here the development and validation of an HPLC–UV assay to quantify the frequently administered 9antiretroviral compounds including dolutegravir and rilpivirine.A simple solid phase extraction procedure was applied to 500 μL aliquots of plasma.The chromatographic separation of the drugs and internal standard(quinoxaline) was achieved with a gradient of acetonitrile and sodium acetate buffer on a C_(18) reverse-phase analytical column with a 25 min analytical run time.Calibration curves were optimised according to the therapeutic range of drug concentrations in patients,and the coefficient of determination(r^2) was higher than0.99 for all analytes.Mean intraday and interday precisions(RSD) for all compounds were less than 15.0%,and the mean accuracy(% deviation from nominal concentration) was also found to be less than 15.0%.Extraction recovery range was between 80% and 120% for all drugs analysed.The solid phase extraction and HPLC–UV method enable a specific,sensitive,and reliable simultaneous determination of nine antiretroviral agents in plasma.Good extraction efficiency and low limit of HPLC–UV quantification make this method suitable for use in clinical trials and therapeutic drug monitoring.

Statistical study of EUV and X-ray transient brightenings

Using the visual inspection and base difference method and data from the X-ray Telescope （XRT） onboard Hinode and TRACE with improved spatial and temporal resolution, we selected 48 X-ray transient brightenings （XTBs） and 237 EUV transient brightenings （ETBs） to study the connection between these two types of transient brightenings （TBs）. These ETBs and XTBs have smaller areas （8.42 Mm^2 and 36.3 Mm^2, respectively, on average） and shorter durations （9.0 min and 6.9 min, respectively, on average） than previous studies. These XTBs show three types of morphological structure： point-like, single-loop and multiple-loop. We find only 20% of the ETBs have corresponding XTBs while the other 80% have no X-ray signatures at all. This is presumably due to the small amount of released energy, which is not enough to heat the plasma to coronal temperatures which produce X-ray emission rather than being due to the limitation of spatial resolution and temperature sensitivity of the X-ray instrument. These small ETBs may significantly contribute to the coronal heating.

Observations of EUV and soft X-ray recurring jets in an active region

We present simultaneous observations of three recurring jets in EUV and soft X-ray （SXR）, which occurred in an active region on 2007 June 5. By comparing their morphological and kinematic characteristics in these two different wavelengths, we found that EUV and SXR jets had similar locations, directions, sizes and velocities. We also analyzed their spectral properties by using six spectral lines from the EUV Imaging Spectrometer （EIS） onboard Hinode and found that these jets had temperatures from 0.05 to 2.0MK and maximum electron densities from 6.6× 10^9 to 3.4× 10^10cm^-3. For each jet, an elongated blue-shifted component and a red- shifted component at the jet base were simultaneously observed in the Fe XII A195 and the He II A256 lines. The three jets had maximum Doppler velocities from 25 to 121 km s-1 in the FexII A195 line and from 115 to 232 km s -1 in the HeII A256 line. They had maximum non-thermal velocities from 98 to 181 km s-1 in the Fe xII A195 line and from 196 to 399 km s-1 in the He II A256 line. We also examined the relationship between averaged Doppler velocities and maximum ionization temperatures of these three jets and found that averaged Doppler velocities decreased with the increase of maximum ionization temperatures. In the photosphere, magnetic flux emergences and cancelations continuously took place at the jet base. These observa- tional results were consistent with the magnetic reconnection jet model, implying that magnetic reconnection between emerging magnetic flux and ambient magnetic field occurred in the lower atmosphere.

Determination of Tea Saponin in Camellia Seed Oil with UV and HPLC Analysis

A simple procedure is described for the HPLC and UV determination of tea saponin in tea seed oil. Determinate was accomplished with UV wavelength detection 550 nm for saponification sample, and HPLC was done under conditions: C18 analytical column of TC-C18, 4. 6 × 250 mm, column temperature at room temperature, injected sample volume was 10 μL, mobile phase’s methanol, flow-rate 0.8 ml/min and detection wavelength 280 nm.

Autooxidation Mechanism of Pyrogallol and Its Free Radical Effects Studied by Means of ESR,UV and NMR

Pyrogallol(pyrogallic acid)is easy to be autooxidized,forming a free radical under alkaline condition,but the mechanism has not been clear.The mechanism of the autooxidation of pyrogallol was studied with ESR,UV and NMR techniques and it was found that pyrogallol was autooxidized to a quinone radical under alkaline condition.And at the same time oxygen recieved an electron from the reaction to form superoxide anions,the hydroxyl free radical was then produced by HaberWeiss reaction.The oxygen free radicals generated from this process promoted the autooxidation of pyrogallol.

Use of Cucurbita pepo Oil to Fight against the UV Action on the Skin

Skin aging is a process most often attributed to UV [1] and also to the use of creams and other cosmetic products low in antioxidant compounds [2]. Photochemically stable pepo Cucurbita oil can be used as an exogenous cosmetic supplement due to its high antioxidant content. Incorporated in an agar, media containing a synthetic melanin solution with added pumpkin oil are subjected to UV light, the aging thus modeled is followed by the measurement of photoresistance values correlated with chemical and spectrophotometric analyses. This study confirms that pumpkin oil is highly effective in protecting the skin, especially the most sensitive skins such as babies’ skin [3] by reinforcing the action of melanin and also that of albinos without melanin. Indeed its SPF (Significant Sun Protection Factor) index estimated during this work is very consistent, i.e. more than 22% of UVB (280 - 315 nm) radiations are suppressed.

Analytical Method Development and Validation of Filgrastim by UV and RP-UFLC Methods

The research work was carried out for establishing a new Ultra Violet (UV)— Visible spectroscopy and Reverse phase-Ultra Fast Liquid Chromatography (RP-UFLC) method for the analysis and quantification of a biosimilar drug, Filgrastim. Filgrastim or recombinant methionyl granulocyte colony stimulating factor (rGCSF) is a glycoprotein. It has a biological action essential for proliferation and differentiation of hematopoetic and progenitor cells. The UV and RP-UFLC work was carried on a Shimadzu UV1800 Spectrophotometer and Shimadzu Prominence LC-20AD UFLC systems, respectively. The λmax of filgrastim was found to be 215 nm. The correlation coefficient by UV spectroscopy was found to be 0.9994 for the concentration range of 1 to 3 μg/ml in double distilled water. The Reverse phase UFLC was done by using Phenomenex C4 (25 cm × 0.46 cm internal diameter) 15 μ, 300 A° analytical column. The optimized mobile phase for binary elution was Acetonitrile and double distilled water (80:20) with a flow rate of 1 ml/min. The retention time of drug was at 3.2 min. It was observed that the response of the detector was linear in the range of 5 - 15 μg/ml with correlation coefficient value of 0.999. After developing the methods, it was assured for the intended use by validation of the analytical parameters like linearity, accuracy, precision, limit of detection, limit of quantitation, ruggedness and robustness. The results of all the parameters for both the methods were found to be within the acceptance criteria as per the International Council for Harmonisation (ICH) guidelines.

Impact of UV-A Radiation on Erythemal UV and UV-index Estimation over Korea

Because total UV （TUV） in the UV-A region is 100 times higher than in the UV-B region, UV-A is a considerable compo- nent when calculating erythemal UV （EUV） and UV-index. The ratio of EUV to TUV in the UV-A value [EUV（A）/TUV（A）] is investigated to convert the EUV（A） from TUV（A） for broadband observation. The representative value of EUV（A）/TUV（A）, from the simulation study, is 6.9 × 10^- 4 changing from 6.1 ×10^-4 to 7.0 × 10^ -4 as aerosol optical depth, total ozone and solar zenith angle change. By adopting the observational data of EUV（B） and TUV（A） from UV-biometer measurements at Yonsei University [（37.57°N, 126.95°E）, 84 m above sea level], the EUV irradiance increases to 15% of EUV（B） due to the consideration of EUV（A） from the data of TUV（A） observation. Compared to the total EUV observed from the Brewer spec- trophotometer at the same site, the EUV（B） from the UV-biometer observes only 95% of total EUV, and its underestimation is caused by neglecting the effect of UV-A. However, the sum of EUV（B） and EUV（A） [EUV（A＋B）] from two UV-biometers is 10% larger than the EUV from the Brewer spectrophotometer because of the spectral overlap effect in the range 320-340 nm. The correction factor for the overlap effect adjusts 8% of total EUV.

Comparison of degradation reactions of Acid Yellow 61 in both oxidation processes of H_2O_2/UV and O_3

The comparison of degradation of Acid Yellow 61 as a model dye compound in both oxidation processes of H 2O 2/UV and O 3 has been studied. When the decolorization rate of Acid Yellow 61 in both reactions presented similar, it was found there are some differences from the results of AOX removal and production of inorganic ions and organic acids. The results reveal that the H 2O 2/UV has beneficial effect on mineralization than O 3 only for degradation of Acid Yellow 61 solution and it is possible for enhancement of method efficiency by taking longer reaction time and addition of high concentration of oxidants.

Disinfection of Primary Municipal Wastewater Effluents Using Continuous UV and Ozone Treatment

UV radiation and ozonation were investigated as disinfection alternatives for the wastewater treatment plant. The inactivation of total and fecal coliforms using ozone and ultraviolet radiation as separate treatments was evaluated. Different ozone concentrations (3 to 40 mg O3/L) were applied and UV fluencies ranging from 8.5 to 12 mJ/cm2 at different pH values (from 5 to 9) were tested. Best results were obtained for ozone doses near 20 mg/min with removals of 72% and 78% of fecal and total coliforms, respectively. The ozone also was capable of oxidizing organic matter in the effluent measured as COD (the highest removal obtained was 36% for 20 mg O3/min). Maximum bacterial resistance was observed at pH 7 in both cases. The UV light offered a high bacterial inactivation (over 80%) and the lowest bacterial inactivation was observed at pH 7. Finally, we obtained the electric energy per order (EEO, kWh/m3/order), defined as the electric energy (kW-h) required to degrade a contaminant by one order of magnitude in a unit volume of contaminated water, being noteworthy that EEO values for the UV process resulted were lower than those determined for the process with ozone in all the water flow tested.

Obtaining space-based SDO/AIA solar UV and EUV images from ground-based Hαobservations by deep learning

In this work,we explore the mappings from solar images taken in Hα(6563 A)by the Global Oscillation Network Group(GONG)on the ground to those observed in eight different wavelengths(94,131,171,193,211,304,335 and 1600 A)by SDO/AIA in space.Eight mappings are built by training the conditional Generative Adversarial Networks(cGANs)on datasets with 500 paired images,which are[Hα,AIA94],[Hα,AIA131],[Hα,AIA171],[Hα,AIA193],[Hα,AIA211],[Hα,AIA304],[Hα,AIA335]and[Hα,AIA1600].We evaluate the eight trained cGANs models on validation and test datasets with 154-pair images and 327-pair images,respectively.The model generated fake AIA images match the corresponding observed AIA images well on large-scale structures such as large active regions and prominences.But the small-scale flare loops and filament threads are difficult to reconstruct.Four quantitative comparisons are carried out on the validation and test datasets to score the mappings.We find that the model-generated images in 304 and 1600 A match the corresponding observed images best.This exploration suggests that the cGANs are promising methods for mappings between ground-based Ha and space-based EUV/UV images,while some improvements are necessary.

Solvent Effects on the UV Absorption Spectrum of Carmofur

In this article, we reported that carmofur could be induced by some solvent to produce conformational alteration. Ultraviolet (UV) spectra were used to study the conformation alteration of carmofur. Upon the addition of acid in the some solvent, UV spectroscopy of carmofur could change gradually. When base was added to this system, UV spectroscopy of carmofur could return to the original state, and the change process was reversible. The variable temperature 1H and 13C-NMR spectrum were used to testify that temperature did not have any effect on the conformation alteration of carmofur in Acetonitrile: Trifluoroacetic-acid (9:1). These two conformers of carmofur were structurally stable in Acetonitrile: Trifluoroacetic-acid (9:1).