On joint analysing XMM-NuSTAR spectra of active galactic nuclei

A recently released XMM-Newton note revealed a significant calibration issue between nuclear spectroscopic telescope array(NuSTAR)and XMM-Newton European Photon Imaging Camera(EPIC)and provided an empirical correction to the EPIC effective area.To quantify the bias caused by the calibration issue in the joint analysis of XMM-NuSTAR spectra and verify the effectiveness of the correction,in this work,we perform joint-fitting of the NuSTAR and EPIC-pn spectra for a large sample of 104 observation pairs of 44 X-ray bright active galactic nuclei(AGN).The spectra were extracted after requiring perfect simultaneity between the XMM-Newton and NuSTAR exposures(merging good time intervals(GTIs)from two missions)to avoid bias due to the rapid spectral variability of the AGN.Before the correction,the EPIC-pn spectra are systematically harder than the corresponding NuSTAR spectra by■subsequently yielding significantly underestimated cutoff energy E_(cut)and the strength of reflection component R when performing joint-fitting.We confirm that the correction is highly effective and can commendably erase the discrepancy in best-fitΓ,E_(cut),and R.We thus urge the community to apply the correction when joint-fitting XMM-NuSTAR spectra,but note that the correction is limited to 3–12 keV and therefore not applicable when the soft X-ray band data are included.Besides,we show that as merging GTIs from two missions would cause severe loss of NuSTAR net exposure time,in many cases,joint-fitting yields no advantage compared with utilizing NuSTAR data alone.Finally,We present a technical note on filtering periods of high background flares for XMM-Newton EPIC-pn exposures in the small window(SW)mode.

文艺的形态学研究

形态学是关于结构的学说。文艺形态学作为美学的一个领域,研究艺术世界内部的结构。自六十年代起,苏联美学界认为审美现象和艺术活动是复杂地组织起来的系统,是多侧面而完整的。用任何单一的方法去研究,都不能作出符合实际的解释,把不同的研究方法机械地结合起来也难以奏效,而系统方法揭示了完整地理解审美客体的前景。在苏联美学界中,对系统方法倡导最力、著述最丰的当推卡冈。他的《艺术形态学》

Electronic Structures, DNA-binding, SAR, and Spectral Properties of Ruthenium Methylimidazole Complexes [Ru（MeIm）4L]^2＋（L=iip,tip,2ntz）

Theoretical studies on the electronic and geometric structures, the trend in DNA-binding affinities as well as the the structure-activity relationship （SAR） of a series of water-soluble Ru（II） methylimidazole complexes, i.e. [Ru（Mehn）4iip]^2＋ （1） （MeIm=l-methylimidazole, iip=2-（1H-imidazo-4-group）-lH-imidazo[n,5-f][1,10]phenanthroline）, [Ru（MeIm）4tip]^2＋ （2） （tip=2-（thiophene-2-group）-lH-imidazo[4,5-f] [i,10]phenanthroline）, and [Ru（Melm）42ntz]^2＋ （3） （2ntz=2-（2-nitro-l,3-thiazole-5-group）-lH-imidazo[4,5-f][1,10]phenanthroline）, were car- ried out using the density functional theory （DFT）. The electronic structures of these Ru（II） complexes were analyzed on the basis of their geometric structures optimized in aqueous solution, and the trend in the DNA-binding constants （Kb） was reasonably explained. The results show that the replacement of imidazole ligand by thiophene ligand can effectively improve the DNA-binding affinity of the complex. Meanwhile, it was found that introduc- ing the stronger electronegative N atom and NO2 group on terminal loop of intercalative ligand can obviously reduce the complex＇s LUMO and HOMO-LUMO gap energies. Based on these findings, the designed complex [Ru（MeIm）42ntz]^2＋ （3） can be expected to have the greatest Kb value in complexes 1-3. In addition, the structure-activity relationships and antitumor mechanism were also carefully discussed, and the antimetastatic activity of the designed complex 3 was predicted. Finally, the electronic absorption spectra of this series of complexes in aqueous solution were calculated, simulated and assigned using DFT/TDDFT methods as well as conductor-like polarizable continuum model （CPCM）, and were in good agreement with the experimental results.

Raman spectroscopy and ionic structure of Na_3AlF_(6-)Al_2O_3 melts

Raman spectrum of molten cryolite was recorded. Based on the new understanding of the scattering coefficients, contents of various structural entities in acidic NaF-AlF3 melts at 942-1 024 ℃ in previous research were reanalyzed. The new quantitative analysis results show that when cryolite ratio（CR） is less than 2, AlF4- is the dominant anion in the melts, and its mole fraction is about 0.70 for melts with CR=1.5 and 0.50 for melts with CR=2. When CR is more than 2.5, the mole fraction of AlF6^3- is relatively large, which is around 0.45 for melts with CR=2.5. Ionic structure of Na3AlF6-Al2O3 melts was investigated by UV-Raman spectroscopy. Octahedral AlF6^3- and tetrahedral AlF4- are proved to exist with possible partial replacement of F- by O^2-. Al2O2F4^2- with a large scattering coefficient also exists in the melts in which alumina concentration is more than 4% （mass fraction）. The increase of temperature causes blue-shift of the bands in the Raman spectra.

用量子力学讨论氢原子问题

本论文在量子力学理论计算的基础之上,对求解出来的能量及能量本征函数对氢原子的光谱系、能级、简并度、概率分布以及电流分布与磁矩的变化等性质进行了详细讨论,并对其给予了定量的解释说明。

Study on FTIR Spectra of Corn Germs and Endosperms of Three Different Colors Combining with Cluster Analysis

[Objective] This research aimed to study the FTIR spectra of corn germs and endosperms so as to provide a scientific way for identifying corn of different types. [Method] The corn germs and endosperms of three types were studied by using Fourier transform infrared spectroscopy（FTIR） technology, combined with cluster analysis. [Result] The overall characteristics of original FTIR spectra were basically similar within the range of 700-1 800 cm^-1. The FTIR spectra were mainly composed by the absorption peaks of polysaccharides, proteins and lipids. Within the wavelength range of 700-1 800 cm^-1, there were only tiny differences in original FTIR spectra among the corn germs and endosperms of three different types. The spectra were then processed by using first derivative and second derivative. The second derivative spectra were used for hierarchical cluster analysis（HCA）. The results showed that with the wavelength range of 700-1 800 cm^-1, the second derivative spectra of the 52 samples could be better clustered according to the tree types and corn germ and corn endosperm. The clustering correct rate reached 96.1%.[Conclusion] FTIR technology, combined with cluster analysis, can be used to identify different types of corn germs and endosperms, and it is characterized by convenience and rapidness.

Orientation of Pigments in the Isolated PhotosystemⅡSub-core Reaction Center CP47/D1/D2/Cyt b-559 Complexes:A Linear Dichroism Study

Linear dichroism (LD) spectroscopy is an important technique in the study of the orientation and organization of pigments in the photosynthetic membrane complexes in vivo and in vitro . In this work, the orientation of the pigments in the isolated photosystem Ⅱ (PSⅡ) sub_core reaction center complexes was analyzed and characterized by means of low temperature absorption and LD spectroscopy. The preparations containing different amounts of CP47 isolated from spinach (Spinacia oleracea L.) chloroplast were used in order to investigate the orientation of pigments in the PSⅡ sub_core CP47/D1/D2/Cyt b_559 (CP47/D1/D2) complexes. Chlorophyll a (Chl a) absorbing at 680 nm in CP47/D1/D2/Cyt b_559 complex showed an orientation of the Q y transition parallel to the membrane plane. It is proposed that there are two forms of β_carotene (β_Car) in CP47/D1/D2/Cyt b_559 complex, denoted as β_Car (Ⅰ) and β_Car (Ⅱ), with different orientations, β_Car (Ⅰ) at 470 and 505 nm is roughly parallel to the membrane plane, and β_Car (Ⅱ) at 460 and 490 nm seems to be perpendicular orientation. Upon the photoinhibitory experiment β_Car (Ⅱ) was found to be photosensitive and easily photodamaged. It also showed that the positive LD signal observed at 680 nm was quite complicated. This signal is tentatively attributed to P680 and some Chl a of antenna in CP47 protein based upon our measurements.

Spectral Properties and Characterization of the Modified PSⅡ Core Complexes

用组氨酸的特异性修饰剂 (DEPC)对PSⅡ核心复合物进行了化学修饰 ,并对其光谱性质进行了研究。研究结果表明 :修饰后的PSⅡ核心复合物的吸收光谱在红区发生了很大变化 ,随修饰时间的增加 ,6 80nm处的吸收逐渐下降。修饰后的PSⅡ核心复合物的荧光光谱在最初的 1min内出现荧光上升现象 ,然后逐渐下降 ,峰位蓝移。这些研究结果表明 ,组氨酸残基的修饰导致了原初电子供体P6 80结构的破坏 ,并对其功能产生了影响。

Hyperspectral Intelligent Monitoring System of Major Soil Nutrients Based on ArcGIS Engine

Based on the object-oriented concept,the hyperspectral intelligent monitoring system of major soil nutrients was designed and developed by using C# and ArcGIS Engine in combination with Microsoft SQL Server.The system mainly includes the following functions：file operation,basic map operation,spectral preprocessing,model management,nutrient content quick calculation,spatial distribution analysis,user management and so on.This system can accomplish the input and preprocessing of soil hyperspectra,and calculate the content of major nutrients,such as soil organic matter,nitrogen,phosphorus as well as potassium quickly and intelligently based on hyperspectral data.Thereby,the soil nutrients regional distribution in the research area can be analyzed by using the principle of geostatistics.This study can not only promote the practicability of soil quantitative remote sensing,but also provide references for the decision-making of agricultural fertilizing.

Physico-Chemical Properties and Laboratory Hyperspectral Reflectance of Coastal Saline Soil in Shangyu City of Zhejiang Province, China

45 and 50 composite soil samples were collected, respectively, from twoagricultural fields, that were enclosed and reclaimed from coastal tidal-flat areas in 1996 and 1984respectively, in Shangyu of Zhejiang Province, China, to investigate the physico-chemicalproperties and the hyperspectral characteristics of the saline soils and to make an assessment ontheir relationships. The reflectance spectra of saline soils were measured using a spectroradiometerin laboratory. The mean spectral curves of the saline soils from the two sites different inreclamation year showed that the saline soil taken from the recently reclaimed land with highersalinity demonstrated a lower reflectance intensity in the spectral region from about 550 nm to 2300nm. In addition, nine absorption bands, i.e., 488 nm, 530 nm, 670 nm, 880 nm, 940 nm, 1400 nm, 1900nm, 2 200 nm and 2 300 nm, were chosen as the spectral bands to investigate the relationshipsbetween soil physico-chemical properties by means of Pearson correlation analysis. Finally, thefirst two principal components were calculated from nine absorption bands and used to discriminatethe saline soil samples taken from two sampled fields. The results indicate that it is feasible todetect physico-chemical properties of saline soils from fields reclaimed for varying time periods onthe basis of the hyperspectral data.

The Influence of Surfactants on Chlorophyll Binding Status and Excitation Energy Transfer in Photosystem Ⅰ of Wheat

Surfactants are widely used in the purification and research of structure and function of the protein complexes in photosynthetic membrane. To elucidate the mechanism of interaction between surfactants and photosystem Ⅰ (PSⅠ), effects of two typical surfactants, Triton X_100 and sodium dodecyl sulfate (SDS) on PSⅠ, were studied at different concentrations. The results were: SDS led to the reduction of apparent absorption intensity and blue shift of absorption peaks; while Triton X_100 led to the decrease of apparent absorption intensity in red region and blue shift of the peak, but to the increase of apparent absorption intensity in blue region. The fourth derivative spectra show that the longwavelength (669 nm and 683 nm) absorbing chlorophyll a was affected greatly and their relative changes of absorbance were axially symmetrical. The presence of surfactant could make the long wavelength fluorescence emission decrease greatly and a new fluorescence peak appeared around 680 nm, it was obvious that the surfactant interceded the transfer of excitation energy from antenna pigments to reaction center. The surfactants might affect the microenvironment of proteins, even the structure of PSⅠ protein subunits and hence changed the binding status of pigments with protein subunits, or the pigments might be released from the subunits. All of these might affect the absorption and the transfer of excitation energy.

Novel si mulation method for fiber Bragg grating under inhomogeneous strainfields

The spectra of fiber Bragg grating (FBG) in inhomogeneous strain fields are distorted due to its inhomogeneity of both the periods and the effective refractive index. The couple mode theory and the Runge-Kutta method can be employed for exact simulation of the spectrum of Bragg grating in such field, but the convergence speed is slow. On the other hand, although the transfer matrix method could be used with higher convergence speed, the precision is poor because of the neglect of the grads of strain change. By improving the FBG equivalent period, a novel simulation method based on a modified transfer matrix method is proposed, which has the advantage of quick-convergence as well as good accuracy.

Throughput Analysis of Dynamic Spectrum Anti-Jamming Multiple-Access in HF Communication Systems

A multiple-access networking scheme based on the new dynamic spectrum anti-jamming system is proposed in this paper. The network consists of a center node and multiple user nodes. The center node detects spectrum holes in the operation band periodically according to the user performance target. Detected spectrum holes are allocated to users who request communication. Throughput of this networking scheme is analyzed over a high-frequency(HF) interference channel. The effect of error correction coding and spectrum hole information transmission error is discussed. Throughput of this scheme and conventional frequency-hopping multiple-access(FHMA) scheme are compared. Results show that user performance increase leads to throughput decrease, which can be offset by error correction coding. If spectrum hole information transmission is in error, the throughput is not affected much as long as the bit error rate is below 10-2. Furthermore, throughput of this scheme is obviously superior to the throughput of FHMA scheme.

A research on statistical retrieval algorithms and spectral characteristics of the total absorption coefficients in the Yellow Sea and the East China Sea

This paper suggests a group of statistical algorithms for calculating the total absorption coefficients based on in situ data of apparent optical property and inherent optical property collected with strict quality assurance according to NASA ocean bio-optic protocols in the Yellow Sea and the East China Sea in spring 2003. The band-ratios ofRrs412/Rrs555, Rrs49o/Rrs555 are used in the algorithms to derive the total absorption coefficients （at） at 412, 440, 488, 510, 532 and 555nm bands, respectively. The average relative errors between inversed and measured values are less than 25.8%, with the correlative coefficients （R2） being 0.75-0.85. Error sensitivity analysis shows that the maximum retrieval error is less than 24.0% at ＋5% error in Rrs＇s. So the statistical algorithms of this paper are practicable. In this paper, the relations between the total absorption coefficients at 412, 488, 510, 532, 555 nm and that of 440nm are also studied. The results show that the relations between the total absorption coefficients of 400-600 nm and that of 440 nm are correlated well and all of their correlative coefficients R2 are greater than 0.99. Furthermore, a regression analysis is also done for the slope of the linear relations and wavelengths, and the R2 is also 0.99. Thus it is possible to retrieve other bands＇ total absorption coefficients with only one band absorption value, which significantly reduce the number of unknown parameters in studying other ocean color related problems.

Optical Remote-sensing Monitoring and Forecasting of Atmospheric Pollution in Huaibei Area, China

Huaibei is an energy city. Coal as the primary energy consumption brings a large number of regional pollution in Huaibei area. Differential optical absorption spectroscopy （DOAS） as optical remote sensing technology has been applied to monitor regional average concen- trations and inventory of nitrogen dioxide, sulfur dioxide and ozone. DOAS system was set up and applied to monitor the main air pollutants in Huaibei area. Monitoring data were obtained from 7 to 28 August, 2011. Monitoring results show measurements in controlling pollution are effective, and emissions of pollutants are up to the national standard in Huaibei area. Prediction model was also created to track changing trend of pollutions. These will provide raw data support for effective evaluation of environmental quality in Huaibei area.

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.

Transmission spectra of one-di mensional photonic crystals including negative-refractive-index media

We introduce a new model of one-dimensional （1D） photonic crystal composed of alternately arranged RHM and LHM layers with positive and negative refractive indices respectively, for which the transmission spectra of the model are calculated numerically with the transfer matrix method, and the bandgap structure and the polarization properties are analyzed. We found that the introduction of negative refractive index layers （i.e. LHM medium layers） gives rise to some peculiar band-gap structure and polarization properties as follows. Firstly, the forbidden bands are extremely wide and the transmission bands are very sharp without oscillation;and secondly, the change of incident angle has different influences on the forbidden bands of TE and TM modes. For the TM mode, the forbidden band width decreases substantially and finally vanishes, and for the TE mode with central wavelength, the total reflection happens at anv incident anale.

Recent Progress in High-speed and High Spectral Efficiency Optical Transmission Technology

Increasing the spectral efficiency and per channel data rate have historically been shown to be the most cost-effective method to meet the need of ever growing capacity demand in the core network. In this paper we review recent progress in high-speed and high-spectral-efficient optical transmission technology. We discuss spectrally efficient modulation and detection technologies that have been experimentally explored for future 100-Gb/s and above optical transmission system. Emerging methods aiming at extending system reach for noise and nonlinearity-stressed high spectral efficiency optical transmission systems have also been reviewed. We show that spectrallyefficient multilevel coding coupled with polarization multiplexing and digital coherent detection has the potential to enable 400Gb/s per channel WDM system operating with existing 50GHzspaced WDM infrastructure at a spectral efficiency of 8b/s/Hz.

Drifting Sand Endangering Gezira Irrigation Scheme in Central Sudan, History and Impact

This study was carried out at Gezira area in Central Sudan that lies between longitude 32° and 32° 50＇ and latitude 14° and 14°15＇. It dealt with the history of the sand, its source and rate of movement towards Gezira scheme and monitored the trend of blowing sand over 10 years. To find out the origin of drifting sand, sand samples were collected from the sandy area west to the White Nile and from the study area. Heavy minerals analysis was carried out on these samples and its mineral assemblage was matched with the mineral of both sand at western bank of the White Nile and the Blue Nile. To picture the trend of moving sand, Multispectral Scanning System （MSS, 1975）, and Thematic Map （TM, 1985） were used to delineate the sandy areas and their trend with time. The rate of the blowing sand was quantified using Bottemane sand catcher. The heavy mineral results showed that the mineral of the drifting sand in the study area are quite similar to the sand of sand dune west to the White Nile indicating the same origin. The sand was transported by southern and southwestern winds through a corridor across the White Nile to its eastern bank, where the most likely water transported sediment was reworked by wind and transported further to the northeast. Between 1972 and 1985, the sand invaded the area at an average rate of about 30 km2 per year and map of 1985 demonstrated a corridor across the White Nile for sand movement. The area was subject to 7 days sand storm with an average of 35 kg/m.d and in summer time, the average amount of moving sand was about 28 kg/m.d. These results demonstrated the future hazard of drifting sand and its impact, which has to be tackled immediately to protect Gezira scheme.

Remote sensing retrieval of total absorption coefficient in the Bohai Sea

Temporal and spatial patterns of inherent optical properties in the Bohai Sea are very complex. In this paper, we used 77 groups of field data of AOPs （apparent optical properties） and IOPs （inherent optical properties） collected in June, August, and September of 2005 in the Bohai Sea, to retrieve the spectral total absorption coefficient a（2） with the quasi-analytical algorithm （QAA）. For QAA implementation, different bands in the region 680-730 nm （in 5 nm intervals） were selected and compared, to determine the optimal band domain of the reference wavelength. On this basis, we proposed a new algorithm （QAA-Com）, a combination of QAA-685 and QAA-715, according to turbidity characterized by a（440）. The percentage difference of model retrievals in the visible domain was between 4.5%-45.1%, in average of 18.8% for a（2）. The QAA model was then applied to Medium Resolution Imaging Spectrometer （MERIS） radiometric products, which were temporally and spatially matched with in-situ optical measurements. Differences between MERIS retrievals and in-situ values were in the range 9.2%-27.8% for a（2） in the visible domain. Major errors in satellite retrieval are attributable to uncertainties of QAA model parameters and in-situ measurements, as well as imperfect atmospheric correction of MERIS data by the European Space Agency （ESA）. During a storm surge in April 2009, time series of MERIS images together with the QAA model were used to analyze spatial and temporal variability of the total absorption coefficient pattern in the Bohai Sea. It is necessary to collect more independent field data to improve this algorithm.