最新刊期
卷 37 ， 期 4 ， 2016
- 摘要：Transparent Ce3+ doped glass ceramics containing LiLuF4 nanocrystals were prepared by melt-quenching method with subsequent heat treatment. XRD results show that the precipitated crystalline phase in the glass matrix is LiLuF4. Under 330 nm light excitation, Ce3+ doped oxyfluoride glass ceramics containing LiLuF4 nanocrystals show more intense emission than the as-made glass, and the emission intensity increases with the increasing of heat treatment temperature and time. The lifetimes of 370 nm emission of Ce3+ doped oxyfluoride glass ceramics are longer than that of as-made glass.关键词：Ce3+;glass ceramic;LiLuF4 nanocrystals;luminescence properties124|162|0更新时间：2020-08-12
- 摘要：Eu/Tm/Tb-doped singly, doubly and triply borosilicate glasses were prepared using a conventional melting-quenching method. The luminescent properties of Eu/Tm/Tb-doped samples under the UV excitation were investigated in detail by measuring the excitation and emission spectra and calculating CIE chromaticity coordinates. The results show that the sharp emission peak centered at 459 nm originating from 1D2→3F4 of Tm3+ is observed, and the characteristic emission intensity centered at 437 nm ascribing to the broad peak of Eu2+, 589 nm(5D0→7F1)and 612 nm(5D0→7F2)of Eu3+ is reduced due to the energy transfer from Eu3+,Eu2+ to Tm3+ ion. Red, green and blue light can be observed in Eu/Tm/Tb -doped triply samples simultaneously under the excitation of 377 nm. The luminescent intensity and color of borosilicate glasses might be changed by adjusting Eu2O3 content, and the sample with CIE chromaticity coordinates(0.33, 0.386 7)are obtained.关键词：borosilicate glasses;Eu/Tb/Tm;spectroscopic property;energy transfer181|150|1更新时间：2020-08-12
- 摘要：The reduced graphene oxide (RGO) coated with large area NiO nanosheets composites were synthesized through a facile one-pot simplified route. The morphology, crystallographic structures and microwave parameters of the composites were investigated by SEM,TEM, XRD and HP8722ES network analyzer. As a result, the RGO/NiO has a much higher reflection loss and wider bandwidth than pure RGO in the low frequency range (2.0-6.6 GHz). The RGO/NiO nanosheets have much higher dielectric loss properties. The interfacial affinity between NiO and GO may increase the numbers of conductive pathways for electron transfer and enhance microwave absorption property of composites consequently.关键词：microwave absorption;graphene;NiO129|98|0更新时间：2020-08-12
- 摘要：Eu3+-doped CeO2 red nanopowders were sol-gel synthesized by using cerium nitrate as raw materials and starch as dispersing agent. In the sol-gel process, the pH value was adjusted by ammonia. The crystal structure, morphology, luminescence properties and chromaticity coordinates of the nanopowders calcined at different temperatures were analyzed by X-ray diffraction patterns, field emission scanning electron microscopy and spectrofluorometer. The results reveal that the obtained samples are of cubic fluorite structure with the space group Fm3m. The particles are approximately spherical with the size of 10-60 nm. With the increase of calcination temperature, the size of CeO2 increases gradually and the red luminescence of the nanopowders is obviously enhanced. After calcination at 800 ℃, the nanopowders can be effectively excited at near UV (370 nm) and blue (468 nm) regions, which is beneficial to the application in solid state lighting. The approach using starch as dispersing agent in sol-gel processes is simple, green and economical for large scale preparation of nanoceria.关键词：sol-gel processes;nanoceria;rare earth;green synthesis;luminescence89|77|1更新时间：2020-08-12
- 摘要：Not only do the photoluminescence (PL) properties of carbon quantum dots (CQDs) depend on their sizes, but also rely on their surface states. Accordingly, the PL behaviors of CQDs could be tuned by doping and/or grafting heteroatoms and groups. In this work, sulfur-and nitrogen-co-doped carbon quantum dots (SN-CQDs) were firstly synthesized by one-step hydrothermal method using p-aminobenzenesulfonicacid as carbon source. Experimental results indicate that the obtained SN-CQDs have a uniform size and are modified by amine and sulphonic acid groups at their surface. Unlike previous reports, the SN-CQDs show the excitation-wavelength-independent photoluminescence behavior and their fluorescence can be quenched by Fe3+ ions. There is a good linear relationship between the Fe3+ concentrations within 0-10-3 mol·L-1 and the fluorescence quenching rates of SN-CQDs. The detecting limit for Fe3+ ions is about 10-7 mol·L-1. The obtained SN-CQDs have the ability of high selectivity, high sensitivity and good anti-jamming capability to ferric iron ions. Accordingly, SN-CQDs can be used for the detection of Fe3+ ions in the environment and organism.关键词：carbon quantum dots;ferric iron ion;fluorescence quenching242|142|9更新时间：2020-08-12
- 摘要：NiO:Cu/ZnO pn heterojunctions with different oxygen concentration were fabricated by magnetron sputtering technology. The rectifying characteristics of NiO:Cu/ZnO pn heterojunctions have been improved with the O2/(Ar+O2) ratio from 0% to 30%, where the average optical transmittance increases from 40% to 80% in the visible range, which may be explained by the improved crystallization due to the reduced defects. When the oxygen partial pressure increases to 80%, the rectifying property is depressed again because of introducing more oxygen into the sample and the appearance of more defects. These results are also evidenced by EDS, XRD, AFM and UV results.关键词：NiO;Cu doping;pn heterojunctions;magnetron sputtering;rectifying property179|102|1更新时间：2020-08-12
- 摘要：To investigate the application of heat capacity high power diode lasers under the condition of low temperature, high transient power and long interval working time, a 3-D transient thermal model was established. By adopting the finite element analysis, the effect of 3-D sizes of the heat sink on the transient thermal characteristics of diode laser was calculated successfully. According to the simulation results, the heat sink with dimension of 26.6 mm×11.5 mm×4 mm was chosen to package the heat capacity diode laser, and the experiments of the diode laser working 3.5 s continuously under -20 ℃ and -30 ℃ were carried out respectively. Eventually, the temperature curves of the active region were obtained and demonstrated a good consistence with the simulation results.关键词：laser;diode laser;heat capacity;transient thermal characteristic162|209|1更新时间：2020-08-12
- 摘要：GaAs substrate was treated by N+ with 150 W RF plasma and followed by rapid thermal annealing. The PL intensity increased by 91%. XPS analysis indicates that GaAs surface has been nitrided after high power RF N+ plasma processing, and the nitridation effect is enhanced under higher RF power. No oxide is found on nitrided GaAs surface. The prepared samples were kept on heat plate in open air for PL stability evaluation, little drop was found during a 30 days test.关键词：plasma;XPS;PL;GaAs87|350|3更新时间：2020-08-12
- 摘要：Numerical simulation model of field plate termination diamond Schottky barrier diode(SBD) was established in this paper, the influence of the field plate length L, insulating layer thickness TOX, substrate doping concentration NB, and the structure shape of the field plate on the electric field distribution inside the device and the influence of breakdown voltage of diamond SBD were numerical simulated by Silvaco device simulation tools ATLAS. The results of numerical simulation were analyzed and explained physically. The breakdown voltage increases with the increasing length of the field plate within the range of 0.0 to 0.2 μm when TOX=0.4 μm and NB=1015 cm-3, and decreases when L>0.2 μm. The breakdown voltage increases with the increasing of insulating layer thickness TOX within the range of 0.1 to 0.4 μm when L=0.2 μm and NB=1015 cm-3, and decreases when TOX>0.4 μm. The breakdown voltage of the device reaches its maximum 1 873 kV when L=0.2 μm, TOX=0.4 μm, and NB=1015 cm-3. The steps field plate can effectively improve the breakdown voltage of the device,compared with the ordinary field plate structure.关键词：field plate termination;diamond Schottky barrier diode;electric field distribution;breakdown voltage98|191|1更新时间：2020-08-12
- 摘要：Based on the generalized nonlinear Schrdinger equation, nonlinear chirped-pulse propagation and supercontinuan (SC) generation in dispersion-flattened dispersion-decreasing fibers (DFDFs) were investigated numerically. The simulation results indicate that the effect of initial chirp parameter on pulse propagation and SC generation is highly related to the choices of pumping conditions and fiber parameters. When DFDF has small normalized quadratic dispersion coefficient, proper positive chirps can significantly enhance the SC bandwidth, while negative chirps or too large positive chirps suppresses the SC bandwidth. There is a wide range of positive chirps that can enhance the SC bandwidth, but the range of proper positive chirps become narrower as input soliton order decreases; When DFDF has large normalized quadratic dispersion coefficient and the pump pulse is a lower-order soliton, the enhancement of SC bandwidth by initial chirp parameter is insignificant, and the widest SC spectrum is generated when the initial chirp is close to zero.关键词：nonlinear optics;supercontinuum;dispersion-flattened dispersion-decreasing fiber101|178|1更新时间：2020-08-12
- 摘要：Three kinds of top-OLEDs with fluorescent dyes-green C545t, yellow Rubrene and red DCJTB were fabricated by reasonable design of microcavity structure, and the corresponding optical properties were also studied. The results show that the spectrum of OLEDs can be narrowed by micro-cavity effect. With the increasing of the viewing angle, the spectral peak of green C545t and yellow Rubrene devices don't change significantly and exhibit independence of the viewing angle, however, an obvious blue shift of red DCJTB device can be observed. The maximum power efficiency of green device is 8.7 lm/W, and the brightness is 7 205 cd/m2 with the current density of 45 mA/cm2. The maximum current efficiency of yellow device is 11.5 cd/A, and the brightness is 3 770 cd/m2 with the current density of 48 mA/cm2. The maximum current efficiency of red device is 3.54 cd/A, and the brightness is 1 358 cd/m2 with the current density of 50 mA/cm2. Not only the chroma and luminous efficiency but also the angle-independence of the top-OLED can be improved by the use of appropriate luminescent material and suitable device structure.关键词：top-emitting organic light-emitting devices;luminescent dyes;microcavity;spectra136|141|3更新时间：2020-08-12
- 摘要：GaN-based multiple quantum wells (MQWs) were epitaxially grown on (0001)-oriented sapphire substrate by metal organic chemical vapor deposition (MOCVD) technique. X-ray diffraction measurements indicated that the MQWs had good periodic structure and smooth interface. By employing bonding and laser lift-off techniques, the MQW structure was sandwiched between two high reflectivity dielectric distributed Bragg reflectors (DBRs), forming a vertical-cavity surface-emitting laser (VCSEL). Under optical pumping, the VCSEL achieved laser action at room temperature with a threshold pumping energy density of about 8.8 mJ/cm2. The laser emitted a blue light at 447.7 nm with a narrow linewidth of 0.11 nm, and had a high spontaneous emission factor of about 6.0×10-2.关键词：GaN;VCSEL;laser lift-off;optical pumping;lasing128|384|5更新时间：2020-08-12
- 摘要：Amorphous indium tungsten oxide (a-IWO) thin film transistors (TFTs) show superior electrical performance and stable properties, but their industrial fabrication methods still need to be developed. In this study, the effect of annealing temperature on the electrical performance of a-IWO TFTs was investigated, where the related basic dependence and physical essence were involved. The experimental results indicate that the field-effect mobility of a-IWO TFTs increases gradually with the annealing temperature increasing, due to the more oxygen vacancies as well as the larger carrier concentration at higher annealing temperatures. Meanwhile, annealing at 200 ℃ led to the best subthreshold swing and threshold voltage of a-IWO TFTs, as is assumed to mainly result from the best front-channel interface caused by the smallest roughness of the a-IWO films annealed at 200 ℃.关键词：amorphous indium tungsten oxide;thin film transistors;annealing temperature;oxygen vacancies;roughness79|182|2更新时间：2020-08-12
- 摘要：A kHz 213 nm DUV solid-state-laser was developed adopting LD side-pumping configuration and electro-optical Q-switched techniques. A fundamental frequency radiation with the output power of 10 W was presented. The laser system could operate stably at the wavelength of 213 nm using multiple frequency techniques. When the pumping current of LD is 80 A, the maximum average output power of 213 nm beam arrives at 151 mW with the repetition rate of 1 kHz, the pulse width of 10 ns, and the power instability of 3%. Then, the polarization matching of the laser beam in the nonlinear crystal was analyzed. Furthermore, the operation properties of the laser system were studied detailedly under different repetition rates.关键词：deep ultraviolet laser;pulse LD pump;solid-state laser93|94|4更新时间：2020-08-12
- 摘要：A new type of water-soluble CdTe quantum dot was synthesized by using mercapto propionic acid as the capping ligand for the detection of enoxacin. The fluorescence intensity of CdTe QDs was significantly quenched in the presence of Cu2+. In the presence of enoxacin,the fluorescence of CdTe QDs was recovered because Cu2+ preferred to react with enoxacin. The degree of recovery of CdTe QDs fluorescence intensity was proportional to the enoxacin concentration, which provided a new method for the detection of enoxacin based on the fluorescence quenching-recovery properties of CdTe QDs. In the presence of 2.3×10-5 mol/L Cu2+ in pH=10 borax buffer solution, the recovered fluorescence of CdTe QDs was linearly related with the enoxacin concentration in the range of 8.0×10-7-3.0×10-5 mol/L with a detection limit of 7.2×10-8 mol/L. This method has been successfully applied for the detection of enoxacin in real samples, and the accuracy is within 95.5%-105.0%.关键词：CdTe quantum dots;enoxacin;Cu2+ ion;fluorescence quenching-recovery100|115|2更新时间：2020-08-12
- 摘要：In order to identity different oil spill by the fluorescence phenomena of oil and its products, the hyperspectral images data of six varieties of oil spills samples were collected under two kind of illuminations (UV and halogen lights) using hyperspectral imaging camera. In the spectral region of 400-720 nm (10 nm spectral bandwidth), four radiation index were obtained which include radiation index of individual spectral bands and the difference, ratio, and the normalized difference radiation index of consecutive spectral bands. Then, a novel method composed of Fisher and PCA to identify most significant wavelengths was proposed, and a classified model based on REF-SVM and the proposed method was established. By comparison, it is found that the different radiation index, light fusions and model consensus of feather selected method all can improve the accuracy of recognition rate. The overall accuracy rate by our method is above 99.1%, which is obviously higher than traditional methods only use one method. The experiment results show that the multi-pattern fusion can effectively improve the recognition rate of marine oil spill.关键词：hyper-spectral imaging;light fusions;band index;model consensus;oil identification113|212|4更新时间：2020-08-12
- 摘要：The binding of levofloxacin (LEFX) with pepsin (PEP) was investigated by spectroscopic and molecular docking methods under simulated physiological conditions. LEFX effectively quenched the fluorescence of PEP by a static quenching process. Based on the results of binding capacity, the thermodynamic parameters were calculated and the molecular docking was studied. It is concluded that the LEFX can spontaneously bind with PEP mainly through electrostatic forces. The three-dimensional fluorescence spectra reveal that the microenvironment and conformation of PEP are demonstrably changed in the presence of LEFX. Since the binding of LEFX can affect the microenvironment of the PEP activity site, LEFX causes the inhibition of PEP activity.关键词：levofloxacin;pepsin;interaction;fluorescence spectroscopy;molecular docking160|69|5更新时间：2020-08-12
- 摘要：Three novel amide derivatives were designed and prepared by the reaction of vanillic acid with 6-aminocaproic acid (EACA), p-aminomethylbeozoic acid (AMBA) or tranexamic acid (AMCA), respectively. The structures were identified by IR, ESI-MS, 1H NMR and 13C NMR. In order to study their hemostatic activity in vitro, the plasma recalcification time (PRT) was determined by traditional method, fluorescence kinetics method and UV kinetics method, respectively. In order to study the stability of derivatives in blood, the interaction between derivatives and human serum albumin (HSA) was investigated under imitated physiological condition by fluorescence spectroscopy, UV-visible absorption spectroscopy and molecular docking, respectively. The results stated clearly that derivatives could reduce PRT significantly and exhibit obvious procoagulant effect in vitro. Moreover, in some concentrations, the hemostatic activity of derivative Ⅱ was better than AMBA. The results obtained by three different methods were in correspondence. New kinetics methods not only avoided artificial error effectually but also had good repeatability. In addition, more reasonable and credible information could be obtained in the process of serum agglutination. On the other hand, the spectra experiments showed that three derivatives could all form stable complexes with HSA respectively. The binding types between derivatives and HSA were all van der Waals force and hydrogen bonds. The results were accordant with molecular docking. It indicates that all the derivatives can be transferred and delivered by HSA to play pharmacological effects at corresponding site. Consequently, there is a strong possibility that the three vanillylamide derivatives can be applied to practice.关键词：vanillic acid;amide derivatives;hemostasia;human serum albumin (HSA);spectroscopic methodology108|146|0更新时间：2020-08-12
- 摘要：Ultraviolet-visible absorption and resonance Raman spectra of all-trans-β-carotene dissolved in cyclohexanol were measured in the temperature range of 65-2 ℃. The sample turns from the liquid state to the solid state at about 22 ℃. After the phase transition, the absorption spectra produce a large blue-shift. With the decreasing of the temperature, the spectra have the same phenomena in the solid and liquid state: the spectra are red-shift, the Raman scattering cross section (RSCS) increases, and the Raman line width decreases. However, the rates of the red-shift (10 times in the liquid state) and the RSCS sharply increase with the temperature in the solid state. It indicates that these results are due to the enhanced modulation effect of the π electron energy gap on the vibration of CC bonds. In this work, we provide some explanations.关键词：all-trans-β-carotene;RSCS;electron-phonon coupling94|49|0更新时间：2020-08-12
- 摘要：Multi parameters are studied in full color LED dispaly panel, which is bothered by the uniformity of gray level while implementation of brightness correction algorithm. The main causes of deviation for brightness correction parameter and image data correction are analyzed, which have serious influence on brightness deviation of gray level. Moreover, a balance algorithm of parameters is proposed, based on which the optimal parameters are selected that can improve uniformity of all gray level and increase gray color. For practicing, accuracy value of the correction parameters is selected as 8 bits, and minimum gray level accuracy of the image data is 0.5, then the interval of image data is [42, 1], based on uniformity index of 97%. Similarly, accuracy value of the correction parameters is selected as 10 bits, and minimum gray level accuracy of the image data is 0.25, then the interval of image data reduces to [20, 1]. Obviously, two gray level of LED display panel is increased.关键词：minimum carry precision;balance formula;gray weight algorithm;gray level115|166|3更新时间：2020-08-12
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