Manufacture and characteristic analysis of YVO_4 laser polarized prisms

A YVO4 crystal Gland-Foucasult prism is manufactured. The relationships between prism structure angle and view field angle are studied with different wavelengths. The results show that the prism with the structure angle of 2 8.180 has a good extinction ratio and the transmission characteristic in both visible and near-infrared regions.

Dynamic Variation and Simulation of Extinction Coefficient of Corn Population

[Objective] The aim was to study the dynamic variation of extinction coefficient of corn population, so as to improve the accuracy of assessment on net primary productivity （NPP） or yield. [Method] Based on the data of photosynthetic active radiation and leaf area index during corn growing season （from May to September） in 2006, observed in Jinzhou observation station of corn farmland ecosystem, China Meteorological Administration, the dynamic variation of extinction coefficient of corn population was analyzed. [Result] There was a great daily variation in the extinction coefficient of corn population during growing season, and the maximum value appeared from 7：00 to 9：00 and from 15：00 to 17：00, while the minimum could be found around 12：00, but the amplitude of variation decreased in tasseling stage. On a large time scale （5 d）, there was a parabolic relationship between extinction coefficient （K） and leaf area index （LAI）, with determination coefficient R2 of 0.960 7. The simulation equation of extinction coefficient, based on the sun elevation angle or leaf area index, had poor accuracy at various time during growing season, so a new dynamic model of extinction coefficient was established, namely K=λ（0.784 8-0.001 6θ）（0.154 8LAI2-0.558 6LAI＋0.654）. [Conclusion] The effect of sun elevation angle and leaf area index on extinction coefficient during corn growing season was considered in the new dynamic model of extinction coefficient, and its simulated result was superior to that of single-factor model.

Comparison of Visibility Measurements over Horizontal Path by Micro-pulsed Lidar and Visibility Meter

As a powerful tool to scan the atmosphere, the I idar can derive visibility values by directly collecting the backscattering laser light from the atmosphere. Simultaneous measurements of atmospheric visibility by Micro-pulsed lidar （MPL） and a commercial visibility meter （VM） NQ-1 have been performed to evaluate the feasibility of the MPL system designed by the Ocean Remote Sensing Laboratory （ORSL） of the Ocean University of China （OUC） from October 21 2005 to November 21 2005 in the Shilaoren Sightseeing Garden on the Qingdao coast. All the 880 data samples obtained by the two instruments have high correlation coefficients （up to 0.86）, which indicates it is feasible to utilize MPL to measure atmospheric visibility.

Dependence of Mixed Aerosol Light Scattering Extinction on Relative Humidity in Beijing and Hong Kong

The hygroscopic properties of mixed aerosol particles are crucial for the application of remote sensing products of aerosol optical parameters in the study of air quality and climate at multiple scales. In this study, the authors investigated aerosol optical properties as a func tion of relative humidity （RH） for two representative me tropolises： Beijing and Hong Kong. In addition to the RH data, mass concentrations of PM10 （particulate matter up to 10 utm in diameter） and aerosol scattering extinction coefficient （aext） data were used. The relationship between the mass scattering extinction efficiency （MEE, defined as O＇ext/PMl0） and RH can be expressed by regression func tions asf= 1.52x ＋ 0.29 （re= 0.77）,f= 1.42x ＋ 1.53 （re= 0.58）,f= 1.19x ＋ 0.65 （re= 0.59）, andf= 1.58x ＋ 1.30 （re = 0.61） for spring, summer, autumn, and winter, respec tively, in Beijing. Here, f represents MEE, x represents I/（1-RH）, and the coefficients of determination are pre sented in parentheses. Conversely, in Hong Kong, the corresponding functions are f= 1.98x- 1.40 （r^2= 0.55）,f = 1.32x - 0.36 （r^2 = 0.26）,f= 1.87x - 0.65 （r^2 = 0.64）, and f= 2.39x - 1.47 （r^2 = 0.72）, respectively. The MEE values for Hong Kong at high RHs （RH 〉 70%） are higher than those for Beijing, except in summer; this suggests that aerosols in Hong Kong are more hygroscopic than those in Beijing for the other three seasons, but the aerosol hy groscopicity is similarly high in summer over both cities. This study describes the effects of moisture on aerosol scattering extinction coefficients and provides a potential method of studying atmospheric visibility and ground level air quality using some of the optical remote sensing products of satellites.

An Empirical Method for Estimating Background Stratospheric Aerosol Extinction Profiles over China

The current paper introduces an empirical method for estimating the vertical distribution of background stratospheric aerosol extinction profiles covering the latitude bands of 50±5°N,40±5°N,30±5°N,and 20±5°N and the longitude range of 75 135°E based on Stratospheric Aerosol and Gas Experiment (SAGE) II aerosol extinction measurements at wavelengths of 1020 nm,525 nm,452 nm,and 386 nm for the volcanically calm years between 1998 2004.With this method,the vertical distribution of stratospheric aerosol extinction coefficients can be estimated according to latitude and wavelength.Comparisons of the empirically calculated aerosol extinction profiles and the SAGE II aerosol measurements show that the empirically calculated aerosol extinction coefficients are consistent with SAGE II values,with relative differences within 10% from 2 km above the tropopause to 33 km,and within 22% from 33 km to 35 km.The empirically calculated aerosol stratospheric optical depths (vertically integrated aerosol extinction coefficient) at the four wavelengths are also consistent with the corresponding SAGE II optical depth measurements,with differences within 2.2% in the altitude range from 2 km above the tropopause to 35 km.

A New Method for Aerosol Retrieval Based on Lidar Observations in Beijing

Lidar has been used extensively in the area of atmospheric aerosol measurement.Two unknowns at the reference altitude,the lidar ratio and the backscatter coefficient,need to be resolved from the lidar equation.In the actual application,these two values are difficult to obtain,particularly the backscatter coefficient.To better characterize the optical properties of aerosols,optical thickness,and attenuated backscatter obtained by other instruments are usually used as the input for joint inversion.However,this method is limited by location and time.In this study,the authors propose a new method for aerosol retrieval by using Mie scattering lidar data to solve this problem.The authors take the horizontal aerosol extinction coefficient as the constraint to begin the iteration until a self-consistent aerosol vertical profile was obtained.By comparing their results with Aerosol Robotic Network(AERONET) data,the authours determine that the aerosol extinction coefficient obtained by combining horizontal and vertical lidar observations is more precise than that obtained by using the traditional Fernald method.This new method has been adopted for retrieving the extinction coefficient of aerosols during the observation days.

In vivo and in situ detection of colorectal cancer using Fourier transform infrared spectroscopy

AIM: Real-time and rapid Identification of the malignant tissue can be performed during or before surgical operation. Here we aimed to detect in vivo and in situ colorectal cancer by using Fourier transform infrared (FTIR) spectroscopy and fiber-optic technology. METHODS: A total of five patients with large intestine cancer were detected in vivo and in situ. Of them, three cases of colon cancer and one case of cecum cancer were detected intraoperatively and in vivo by using a FTIR spectrometer during surgical operation, and one case of rectum cancer was explored non-invasively and in vivo before the surgical operation. Normal and malignant colorectal tissues were detected in vivo and in situ using FTIR spectroscopy on the basis of fundamental studies. RESULTS: There were significant differences between FTIR spectra of normal and malignant colorectal tissues detected in vivo and in situ. Experimental results revealed that the spectral characteristics of normal and malignant tissues found in vivo and in situ were similar to those obtained from in vitro measurement in our previous fundamental research. CONCLUSION: FTIR fiber-optic attenuated total reflectance (ATR) spectroscopy can identify in situ and in vivo colorectal cancer. FTIR spectroscopie method with fiber optics is a non-invasive, rapid, accurate and in vivo cancer detection technique in clinical diagnosis.

Potential oxidative stress in children with chronic constipation

AIM: To investigate the potential oxidative stress in children with -chronic constipation and to explore its mechanisms.METHODS: Seventy children with chronic constipation and 70 age- and sex-matched healthy children were enrolled in a randomized controlled study. Plasma levels of vitamins C and E, activities of superoxide dismutase and catalase and lipoperoxide level in erythrocytes were determined by spectrophotometry.RESULTS: Compared with healthy children whose vitamin C,vitamin E, superoxide dismutase, catalase and lipoperoxide were 58.35±14.42 μmol/L, 27.15±6.55 μmol/L, 2 206±171U/(g· Hb), 327.3±82.2 K/(g·Hb) and 19.18±4.27 nmol/(g·Hb)respectively, the levels of vitamin C, vitamin E, the activity of superoxide dismutase, and catalase in the children with chronic constipation significantly decreased [46.59±11.51 μmol/L,20.65±4.80 μmol/L, 1943±147 U/(g·Hb) and 269.3±67.8 K/(g·Hb),respectively P＜0.01], while the lipoperoxide significantly increased [25.22±5.01 nmol/(g·Hb), P＜0.01]. With a prolonged course of disease, the levels of vitamin C, vitamin E, the activity of superoxide dismutase and catalase in the children with chronic constipation gradually decreased,while the level of lipoperoxide gradually increased.CONCLUSION: Chronic constipation can cause potential oxidative stress in children.

A 155 Mbps laser diode driver with automatic power and extinction ratio control

An integrated laser diode driver(LDD) driving an edge-emitting laser diode was designed and fabricated by 0.35 μm BiCMOS technology. This paper proposes a scheme which combines the automatic power control loop and temperature com-pensation for modulation current in order to maintain constant extinction ratio and average optical power. To implement tem-perature compensation for modulation current,a novel circuit which generates a PTAT current by using the injecting base current of a bipolar transistor in saturation region,and alternates the amplifier feedback loop(closed or not) to control the state of the current path is presented. Simulation results showed that programmed by choice of external resistors,the IC can provide modu-lation current from 5 mA to 85 mA with temperature compensation adjustments and independent bias current from 4 mA to 100 mA. Optical test results showed that clear eye-diagrams can be obtained at 155 Mbps,with the output optical power being nearly constant,and the variation of extinction ratio being lower than 0.7 dB.

Spectral and Energy Efficiency of Downlink MU-MIMO Systems with MRT

This paper studies the achievable spectral efficiency(SE)of downlink multiuser multiple-input-multiple-output(MIMO)system,where the base station(BS)is deployed an arbitrary finite antenna number and communicates simultaneously with many users. We assume that the BS has accurate channel state information(CSI)and adopt maximum ratio transmission(MRT)precoding. An accurate analytical result for the achievable SE is obtained. Based on the analytical result on the achievable SE,we further study the achievable energy efficiency(EE)of multiuser MIMO system by considering an energy consumption model. Results indicate that the increasing number of BS antennas can boost the achievable SE of system,whilst the achievable SE tends to a saturated rate in the high signal-tonoise ratios(SNR)regime. Furthermore,an important conclusion is that the increasing number of users is beneficial for the achievable EE and there is an optimal antenna number to maximize the EE of system.

Load Management Scheme Using Air Conditioning Electric Power Consumption and Photovoltaic Power System Generation

In the last few decades, in the world and also in the European Union, considerable resources had been invested in the rapid development of renewable energy sources and distributed generation in general. At the same time, power consumption is continuously increasing, and consumers are becoming more complex, which ultimately requires new investments in the distribution network. Concept of smart grids is generally accepted as a possible solution. Smart grid is a concept with many elements, where monitoring and control of every element in the chain of production, transmission, distribution and final consumption enable much more efficient delivery and use of electricity. One of the elements of smart grid efficiency is the ability of real-time demand-supply balancing. This balancing is carried out by monitoring of consumption and redistribution of electricity among individual end users, according to their needs. The aim of this paper is creating algorithm for real-time load management using power measurements. Algorithm for real-time load management at the ETFOS （Faculty of Electrical Engineering in Osijek）, Croatia is created based on measurements of photovoltaic power plant production, the power consumption of air conditioning system and the faculty building total electricity consumption. Expected result of real-time re-dispatching of air conditioners consumption, depending on the level of electricity production in photovoltaic power plant is decreasing peak demand of the faculty.

可录蓝光光盘存储材料的研发方法初探

为了满足更高容量的存储需求,采用405nm蓝紫激光的记录介质已经逐步研发并推向市场。这种采用更短波长激光的记录介质统称为蓝光盘,共出现过三种主要的格式:包括HD DVD(简称HD,已退出市场)、Blu-ray Disc(简称BD)、CBHD。

Satellite-based Estimates of Canopy Photosynthetic Parameters for an Alpine Meadow in Northern Tibet

Plant photosynthesis is the fundamental driver of all the biospheric functions. Alpine meadow on the Tibetan Plateau is sensitive to rapid climate change, and thus can be considered an indicator for the response of terrestrial ecosystems to climate change. However, seasonal variations in photosynthetic parameters, including the fraction of photosynthetically active radiation by canopy(FPAR), the light extinction coefficient(k) through canopy, and the leaf area index(LAI) of plant communities, are not known for alpine meadows on the Tibetan Plateau. In this study, we used field measurements of radiation components and canopy structure from 2009 to 2011 at a typical alpine meadow on the northern Tibetan Plateau to calculate these three photosynthetic parameters. We developed a satellite-based(NDVI and EVI) method derived from the Beer-Lambert law to estimate the seasonal dynamics of FPAR, k,and LAI, and we compared these estimates with the Moderate Resolution Imaging Spectroradiometer(MODIS) FPAR(FPAR_MOD) and LAI product(LAI_MOD). The results showed that the average daily FPAR was 0.33, 0.37 and 0.35, respectively, from 2009 to 2011, and that the temporal variations could be explained by all four satellite-based FPAR estimations, including FPAR_MOD, an FPAR estimation derived from the Beer-Lambert law with a constant k(FPAR_LAI), and two FPAR estimations from the nonlinear functions between the ground measurements of FPAR(FAPRg) and NDVI/EVI(FPAR_NDVI and FPAR_EVI). We found that FPAR_MOD seriously undervalued FPARg by over 40%. Tower-based FPAR_LAI also significantly underestimated FPARg by approximately 20% due to the constant k(0.5) throughout the whole growing seasons. This indicated that using FPAR_LAI to validate the FPAR_MOD was not an appropriate method in this alpine meadow because the seasonal variation of k ranged from 0.19 to 2.95 in this alpine meadow. Thus, if the seasonal variation of k was taken into consideration, both FPAR_NDVI and FPAR_EVI provided better descriptions, with negligible overestimates of less than 5% of FAPRg(RMSE=0.05), in FPARg estimations than FPAR_MOD and FPAR_LAI. Combining the satellite-based(NDVI and EVI) estimations of seasonal FPAR and k, LAI_NDVI and LAI_EVI derived from the Beer-Lambert law also provided better LAIg estimations than LAI_MOD(less than 30% of LAIg). Therefore, this study concluded that satellite-based models derived from the Beer-Lambert law were a simple and efficient method for estimating the seasonal dynamics of FPAR, k and LAI in this alpine meadow.

Tiny 2D silicon quantum sheets:a brain photonic nanoagent for orthotopic glioma theranostics

We report that atomically thin two-dimensional silicon quantum sheets(2D Si QSs),prepared by a scalable approach coupling chemical delithiation and cryo-assisted exfoliation,can serve as a highperformance brain photonic nanoagent for orthotopic glioma theranostics.With the lateral size of approximately 14.0 nm and thickness of about 1.6 nm,tiny Si QSs possess high mass extinction coefficient of 27.5 Lg^(-1)cm^(-1)and photothermal conversion efficiency of 47.2%at 808 nm,respectively,concurrently contributing to the best photothermal performance among the reported 2 D mono-elemental materials(Xenes).More importantly,Si QSs with low toxicity maintain the trade-off between stability and degradability,paving the way for practical clinical translation in consideration of both storage and action of nanoagents.In vitro Transwell filter experiment reveals that Si QSs could effectively go across the b End.3 cells monolayer.Upon the intravenous injection of Si QSs,orthotopic brain tumors are effectively inhibited under the precise guidance of photoacoustic imaging,and the survival lifetime of brain tumor-bearing mice is increased by two fold.Atomically thin Si QSs with strong light-harvesting capability are expected to provide an effective and robust 2D photonic nanoplatform for the management of brain diseases.

D-A-π-A organic sensitizers containing a benzothiazole moiety as an additional acceptor for use in solar cells

Three novel triphenylamine-based D-A-r-A-featured dyes （Zl-Z3） have been designed, synthesized and characterized for use in dye-sensitized solar cells. Benzothiazole was incorporated as an additional acceptor, which greatly enhanced the molar ex- tinction coefficient of the dyes. Various conjugated linkers, such as benzene, furan and thiophene, were also introduced to con- figure the novel D-A-n-A framework in order to prolong electron flow and active transportation. Among all dyes, Z2 contain- ing a thiophene linker exhibited the maximum overall conversion efficiency （r/） of 4.16% （Jsc = 9.27 mA cm-2, Voc = 642 mV, FF = 0.70） under standard global AM 1.5 G solar condition.

Convenient and inexpensive determination of optical constants and film thickness of blended organic thin film

This work presents the study of optical constants and film thickness of blended organic thin films, emphasizing on the modeling procedure with modified genetic algorithm aided by absorption or transmittance spectra of both pure materials and the blends. Taking the blending of copper phthalocyanine(Cu Pc) and fullerene(C60) as an example, a simple, convenient and low-cost method for the determination of the optical constants and film thickness of blended organic thin films was demonstrated. New scheme for optical modeling of blended organic thin film was proposed by introducing peak energies of Cody-Lorentz oscillators of the pure materials, which were determined by fitting the film absorption of pure materials. These oscillators of pure materials could be recognized in the transmittance spectrum of their blends, and were further used as the initial searching ranges in the simulation of blended films. As a result, the constraint bounds of the unknown parameters were significantly reduced and modeling efficiency as well as fitting accuracy was improved. For instance, the fitting of the transmittance curves of blended films with different blending ratios reached reliable results in comparison with extinction coefficients obtained from experiment.

Preparation of nanophase M-type ferrite and its laser-attenuated characteristics

By citrate sol-gel auto-combustion method,the nanophase M-type planar hexagonal ferrite is prepared.The transmission electron microscopy(TEM),X-ray diffraction(XRD) and thermal analysis are used to study the grain size,phase composition,microstructure and crystallization process.The results show that the nanophase M-type Sr-ferrite prepared by this method is single,and its grain size is smaller than 100 nm.Moreover,most of the grains present hexagonal sheet shape.Tests are carried out for its attenuation to 1.06 mm laser.It is found that the extinction capability of the nanophase M-type Sr-ferrite smoke is good,and its mass extinction coefficient is 1.628 m2/g.

Correlation between the molecular structure and transcis isomerization characteristics of azobenzenes

Photochemical and thermal isomerization of various azobenzenes was systematically investigated to understand the correlation between the molecular structure and trans → cis isomerization characteristics of azobenzenes. A blue shift in π-π absorption band of ortho-alkylated azobenzenes （1o and 2o） was observed together with a reduction in molar extinction coefficient （e） in comparison with both meta-alkylated azobenzenes （4m and 5m） and 7p lacking the meta and ortho substituents. For orthoalkylated azobenzene, photochemical trans-to-cis isomerization and thermal back cis-to-trans isomerization in solution oc- curred slowly when compared with 4m, 5m and 7p. The half-life time of the cis form of 20 was found to be 380 h, which is about 8-50 times longer than those of comparable 4m, 5m （43-13 h） and 7p （7 h）. Furthermore, comparison of the molecular structure and isomerization characteristics of azobenzene thiol （20 and 5m） self-assembled monolayers on flat gold surfaces indicates that the trans-to-cis photoconversion in monolayer systems is influenced by steric hindrance and strong intermoleculax interaction between azobenzene units.

Extinction Effects of Multiplicative Non-Gaussian L′evy Noise in a Tumor Growth System with Immunization

The extinction phenomenon induced by multiplicative non-Gaussian L′evy noise in a tumor growth model with immune response is discussed. Under the influence of the stochastic immune rate, the model is analyzed in terms of a stochastic differential equation with multiplicative noise. By means of the theory of the infinitesimal generator of Hunt processes, the escape probability, which is used to measure the noise-induced extinction probability of tumor cells, is explicitly expressed as a function of initial tumor cell density, stability index and noise intensity. Based on the numerical calculations, it is found that for different initial densities of tumor cells, noise parameters play opposite roles on the escape probability. The optimally selected values of the multiplicative noise intensity and the stability index are found to maximize the escape probability.

A kind of denoising method for airborne waveform sampling LiDAR

This paper describes a full waveform sampling LiDAR system applying stripe principle. A kind of denoising method based on edge detection of original stripe signal is proposed. This method is compared with other denoising methods, such as Wiener filtering, mean filtering and median filtering. It is found that the proposed denoising method is much more effective for dealing with the waveform signals.