基于多尺度功率谱子带梯度的宽带频谱感知算法与性能分析

为了应对复杂环境下非合作通信、电磁频谱监管等宽带接收中存在的先验信息缺失、信道失真严重以及频域呈现不平坦色噪声的挑战,提出一种基于多尺度功率谱子带梯度的宽带频谱感知算法,该算法不要任何的先验信息,对功率谱进行分段计算梯度,再进行自适应双阈值检测,通过多尺度的技巧提高了宽带频谱感知的稳定性。对该算法在不同信道模型下的统计特性、虚警概率、检测概率以及判决门限的表达式进行了理论推导。理论分析和实验仿真表明,算法适用于高斯噪声信道和平坦衰落信道,能够有效克服色噪声,并且能够实现用户频带范围定位,运算复杂度低、实时性强,对噪声不确定度具有稳健性,能够用于低信噪比场合。

纳雍县水东乡民间二胡“谱子”浅析

纳雍是贵州毕节地区的贫困县之一,其所辖原居仁区(六区)含十个乡,现撤区并乡后为王家镇和水东乡。水东乡(含原箱子、保落、水东、老包、木城五乡)与大方县和织金县毗邻,这里河道深切,山高林密,数十里之遥常无人烟。这里是苗族、汉族、穿青族(国家未承认而贵州承认的一少数民族)的杂居地,人民生活朴素、节俭,情感粗放而纯洁,音乐素材丰富而原始,本人曾在此工作三、四年之久,对这里的民间音乐作过深入的调查,现经整理对其中的民间二胡“谱子”问题作如下分析。

“谱子戏”和“梁子戏”的区别与优劣

二人转有“谱子戏”和“梁子戏”之分，很多年来，二人转演员，以及从事东北地方戏曲创作的音乐工作者们对两种形式孰优孰劣进行过多次的探讨，但凡事只要存在就会有它的必然性，“谱子戏”的科学性和艺术性，“梁子戏”的细腻性，随意性都是二人转这门艺术传承发展的精华。两者共融取利弊劣才能造就出更加完美的东北二人转的曲风。

Temperature-Induced Unfolding Pathway of Staphylococcal Enterotoxin B:Insights from Circular Dichroism and Molecular Dynamics Simulation

In this study,circular dichroism(CD)and molecular dynamics(MD)simulation were used to investigate the thermal unfolding pathway of staphylococcal enterotoxin B(SEB)at temperatures of 298–371 and 298–500 K,and the relationship between the experimental and simulation results were explored.Our computational findings on the secondary structure of SEB showed that at room temperature,the CD spectroscopic results were highly consistent with the MD results.Moreover,under heating conditions,the changing trends of helix,sheet and random coil obtained by CD spectral fitting were highly consistent with those obtained by MD.In order to gain a deeper understanding of the thermal stability mechanism of SEB,the MD trajectories were analyzed in terms of root mean square deviation(RMSD),secondary structure assignment(SSA),radius of gyration(R_(g)),free energy surfaces(FES),solvent-accessible surface area(SASA),hydrogen bonds and salt bridges.The results showed that at low heating temperature,domain Ⅰ without loops(omitting the mobile loop region)mainly relied on hydrophobic interaction to maintain its thermal stability,whereas the thermal stability of domain Ⅱ was mainly controlled by salt bridges and hydrogen bonds.Under high heating temperature conditions,the hydrophobic interactions in domain Ⅰ without loops were destroyed and the secondary structure was almost completely lost,while domain Ⅱ could still rely on salt bridges as molecular staples to barely maintain the stability of the secondary structure.These results help us to understand the thermodynamic and kinetic mechanisms that maintain the thermal stability of SEB at the molecular level,and provide a direction for establishing safer and more effective food sterilization processes.

Rate Law for Photoelectrochemical Water Splitting Over CuO

Photocatalytic splitting of water over p-type semiconductors is a promising strategy for production of hydrogen.However,the determination of rate law is rarely reported.To this purpose,copper oxide(CuO)is selected as a model photocathode in this study,and the photogenerated surface charge density,interfacial charge transfer rate constant and their relation to the water reduction rate(in terms of photocurrent)were investigated by a combination of(photo)electrochemical techniques.The results showed that the charge transfer rate constant is exponential-dependent on the surface charge density,and that the photocurrent equals to the product of the charge transfer rate constant and surface charge density.The reaction is first-order in terms of surface charge density.Such an unconventional rate law contrasts with the reports in literature.The charge density-dependent rate constant results from the Fermi level pinning(i.e.,Galvani potential is the main driving force for the reaction)due to accumulation of charge in the surface states and/or Frumkin behavior(i.e.,chemical potential is the main driving force).This study,therefore,may be helpful for further investigation on the mechanism of hydrogen evolution over a CuO photocathode and for designing more efficient CuO-based photocatalysts.

知识嵌入的医疗对话生成

针对以往医疗对话生成方法未能有效建模医学知识,导致生成的回复缺乏医学常识一贯性的问题,很多学者尝试引入医疗知识图谱,但集成医疗知识图谱时容易占用较多输入数据空间,这限制了模型输入可以保留对话上下文信息量的大小。本文提出知识嵌入的医疗对话生成模型(medical conversation generation model based on knowledge embedding,MCG-KE),该模型基于历史对话进行实体预测得到上下文知识嵌入实体,引入串行图编码方式和图注意力机制获得当前对话相关的医疗知识图谱子图编码,将上下文知识嵌入实体、医疗知识图谱子图编码和历史对话编码作为对话生成模型的输入,用于知识嵌入的医疗对话生成。实验结果表明,模型在高效计算的情况下,所生成的医疗对话在自动评价和人工评价等相关指标上的性能均有提升。

沈阳故宫西所外檐彩画现状研究

以沈阳故宫西所外檐彩画为研究对象,分析了彩画的类型、特征及典型现状病害,探究清官式彩画在严寒地区现代赋存环境下的存续现状。采用田野调查、实验分析等研究方法,厘清了西所外檐彩画谱子规制,分析和总结了近四五十年以来的彩画病害和病害分布规律,在西所彩画重绘保护工程即将展开之际,为彩画重绘工程的谱子设计、传统工艺做法的继承和延续以及彩画的预防性保护等工作提供了重要的参考。同时,记录和完善了沈阳故宫彩画保护和管理的历史与经验,为继承和延续彩画传统工艺提供了技术上的佐证和支持。

非正常算子局部谱的若干结果

在本文,我们得到下列结果 1.设T是完全非正常的协亚正常算子,且具单位延拓性质,假设D=TT~*-T~*T满足:是闭的。若△是闭园盘且△°∩σ(T)≠φ,则存在非零元x∈H使得σT(X)(?)△。 2.设T是θ一类算子,则T有单位延拓性质,若T满足σ(T)∩R′=φ,则谱子空间X_T(δ)是闭的,这里δ是C的闭子集,且T有非平凡的不变子空间。

敦煌舞谱的整理与分析(一)

1925年,中国学者刘半农先生首先将在巴黎适录的P.3501残卷编入《敦煌掇琐》,拟名为"舞谱".自此,《敦煌舞谱》遂得到中外学者公认,为世人瞩目.半个多世纪过去了,国内外学术界对敦煌舞谱的研究,可以说仍是寥若晨星.国内学者的研究文章,开始一直只局限于P.3501残卷,主要是从其与唐人打令或声诗、杂言曲词的关系入手来考释谱字、谱词,虽提供了不少有用的参考资料,但并未从分析舞谱本身结构、内容的角度对它作全面、系统的研究.海外学者(主要是日本学者)的论文虽然不乏巨制鸿篇,力图逐卷逐谱地在舞谱的解读上探幽发微,却又忽略了对舞谱残卷本身的科学整理。

谱意义下的非交换Hardy空间(英文)

{αt}t∈G是群G作用在VNA M上的*自同构的σ-弱连续的表示,满足ταt=τ,t∈G.对1≤p<∞,{αt}t∈G可以延拓到非交换Lp空间上.基于谱子空间理论,讨论了非交换Hardy空间Hp(α).

Separation of Ions from Volatile Organic Compounds Using High-Field Asymmetric Waveform Ion Mobility Spectrometry-Mass Spectrometer

A combination of high-field asymmetric waveform ion mobility spectrometry （FAIMS） with mass spectrometer （MS） was analyzed. FAIMS separates ions from the volatile organic compounds in the gas-phase as an ion-filter for MS. The sample ions were created at ambient pressure by ion source, which was equipped with a 10.6 eV UV discharge lamp （A=116.5 nm）. The drift tube of FAIMS is composed of two parallel planar electrodes and the dimension is 10 mm×8 mm×0.5 mm. FAIMS was investigated when driven by the high-filed rectangular asymmetric waveform with the peak-to-peak voltage of 1.36 kV at the frequency of 1 MHz and the duty cycle of 30%. The acetone, the butanone, and their mixture were adopted to characterize the FAIMS-MS. The mass spectra obtained from MS illustrate that there are ion-molecular reactions between the ions and the sample neutral molecular. And the proton transfer behavior in the mixture of the acetone and the butanone is also observed. With the compensation voltage tuned from -30 V to 10 V with a step size of 0.1 V, the ion pre-separation before MS is realized.

Optimization for Purification and Characterization of Recombinant Hirudin Ⅲ from E. coli

Aim To optimize purification conditions of recombinant hirudin 3 in thefermentation broth and characterize the product. Methods Reambinant hirudin 3 was isolated andpurified from the fermentation broth by three column chromatography steps with macroporous resin,DEAE cellulose DES2 and preparative RP-HPLC, respectively, and the optimal conditions were obtained.Purity of the product was determined by SDS-PAGE and analytical RP-HPLC. The molecular weight wasdetermined by mass spec-trometry. The structure of the product was analyzed by peptide map.ResultsThe product with purity of 95.4786% was obtained after three purification steps in the optimumconditions with a total yield of 39%. The molecular weight of the product was 6 913.32 ± 6.55 Da,coincident to the theoretical molecular weight of r-hirudin 3. The structure of the product wascoincident to r-hirudin 3 either. Conclusion The optimized purification steps can be successfullyemployed for purification of r-hirudin 3 from E. coli using batch-type approaches. The productobtained with high purity was confirmed to be r-hirudin 3.

Determination of Arsenic and Mercury in Soil by Microwave Digestion and Hidride GenerationAtomic Fluorescence Spectrometry

[Objective] The aim was to develop a rapid, simple method for determina- tion of arsenic and mercury in soil samples by atomic fluorescence spectrometry. [Method] The method for determination of As and Hg in soil by combined atomic fluorescence spectrometry and microwave digestion was used. [Result] The concentration curve was linear within the range of 0-80.0μg/L of As and 0-8.0 μg/L of Hg, and the detection limits of As and Hg was 0.036 μg/L and 0.015 μg/L, respectively. The precision for elevenfold determination of As at 40.0 ug/L level and Hg at 4.0μg/L level were 1.1% and 2.2%（RSD）, respectively. Recoveries of 103.0%-106.6% for As and 90.0%-95.0% for Hg were obtained for there soil samples. [Conclusion] The proposed method has the advantages of simple operation, high sensitivity, and high efficiency; it was successfully used for determination of As and Hg in soil samples.

Comparison of Phycobiliproteins from Gracilaria lemaneiformis (Rhodophyceae) and Its Pigment Mutants in Spectral and Molecular Respects

Comparative studies of absorption spectra of phycobiliproteins of Gracilaria lemaneiformis Greville and its pigmental mutants were conducted in this study. The results showed that the absorption spectra of phycoerythrins ( PE) from different material changed significantly, while those of phycocyanins (PC) and allophycocyanins (APC) were basically similar. In order to disclose the essence of die difference, partial sequences of die subunit genes of PE of Qingdao strain of G. lemaneiformis (qd) and its pigmental mutants were determined. The amino acid sequences were deduced and used to explain spectral shifts of PE from the pigmental mutants. The amino acid sequences of PE resembled each other, and several residues changed among qd and its pigmental mutants. Residue substitutions were found in a region consisting of amino acids which determined are secondary structure and subunits interactions, thus might influence the confirmation and interaction of subunits, and further caused spectral deviation.

Determination of Chromium and Zinc in Soil by Microwave Digestion and Flame Atomic Absorption Spectrometry

[Objective] The aim was to develop a rapid, simple method for determination of chromium and zinc in soil samples by flame atomic absorption spectrometry.[Method] The method for determination of Cr and Zn in soil by combined flame atomic absorption spectrometry and microwave digestion was used. [Result] The concentration curve was linear within the range of 0-0.8 mg/L for Cr and 0-0.8 mg/L for Zn, the detection limits of Cr and Zn was 0.0025 mg/L and 0.002 3 mg/L, respectively. Recoveries of 102.4%-103.2% for Cr and 97.7%-98.3% for Zn were obtained for there soil samples. [Conclusion] The proposed method has the advantages of simple operation, high sensitivity, and high efficiency; it was successfully used for determination of Cr and Zn in soil samples.

Synthesis,characterization and gas-sensing properties of Pd-doped SnO_2 nano particles

SnO2 nano particles with various Pd-doping concentrations were prepared using a template-free hydrothermal method.The effects of Pd doping on the crystal structure,morphology,microstructure,thermal stability and surface chemistry of these nano particles were characterized by transmission electron microscope,X-ray diffractometer and X-ray photoelectron spectroscope respectively.It was observed that Pd-doping had little effect on the grain sizes of the obtained SnO2 nano particles during the hydrothermal route.During thermal annealing,Pd-doping could restrain the growth of grain sizes below 500℃ while the grain growth was promoted when the temperature increased to above 700℃.XPS results revealed that Pd existed in three chemical states in the as-synthesized sample as Pd^0,Pd^2＋ and Pd^4＋,respectively.Pd^4＋ was the main state which was responsible for improving the gas-sensing property.The optimal Pd-doping concentration for better gas-sensing property and thermal stability was 2.0%-2.5% （mole fraction）.

Tomographic inversion of near-surface Q factor by combining surface and cross-hole seismic surveys

The estimation of the quality factor Q plays a fundamental role in enhancing seismic resolution via absorption compensation in the near-surface layer.We present a new geometry that can be used to acquire field data by combining surface and cross-hole surveys to decrease the effect of geophone coupling on Q estimation.In this study,we drilled number of receiver holes around the source hole,each hole has different depth and each geophone is placed geophones into the bottom of each receiver hole to avoid the effect of geophone coupling with the borehole wall on Q estimation in conventional cross-hole seismic surveys.We also propose a novel tomographic inversion of the Q factor without the effect of the source signature,and examine its stability and reliability using synthetic data.We estimate the Q factors of the near-surface layer in two different frequency bands using field data acquired in the Dagang Oilfield.The results show that seismic absorption in the nearsurface layer is much greater than that in the subsurface strata.Thus,it is of critical practical importance to enhance the seismic solution by compensating for near-surface absorption.In addition,we derive different Q factors from two frequency bands,which can be treated,to some extent,as evidence of a frequency-dependent Q.

Determination of Chlorine and Bromine in Plant Materials by Ion Chromatography

A method was developed for determination of chlorine and bromine in plant materials by ion chromatography using temperature programing-semi molten for sample preparation. Values of detection limits of the method found were 1.0×10^-5 for CI and 1.3×10^-6 for Br. The measuring range of the method found were 0.3-20.0 mg/L for CI and 4,0-120,0 μg/L for Br. The results obtained agreed quite well with those reference values.

Effect of Rapid Thermal Annealing Ambient on Gettering Efficiency and Surface Microstructure in 300mm CZ Silicon Wafers

The effect of rapid thermal annealing （RTA） ambient on denuded zone and oxygen precipitates in Czochralski （CZ） silicon wafers is studied in this paper. N2 and a N2/NH3 mixture are used as RTA ambient. It is demonstrated that a high density of oxygen precipitates and thin denuded zone are obtained in N2/NH3 ambient,while a relatively lower density of oxygen precipitates and thicker denuded zone are observed in N2 ambient. As the RTA duration times increased, the oxygen precipitate density increased and the denuded zone depth decreased. X-ray photoelectron spectroscopy （XPS） data and atomic force microscope （AFM） results show that there RTA process,which can explain the different effect of RTA was a surface nitriding reaction during the N2/NH3 ambient ambient.

Determination of Cadmium and Lead in Sugarcane by Graphite Furnace Atomic Absorption Spectrometer with Zeeman Correction

[Objective] The aim was to develop a rapid,simple method for determination of cadmium and lead in sugarcane samples by graphite furnace atomic absorption spectrometry.[Method] The method for determination of Cd and Pb in sugarcane by combined graphite furnace atomic absorption spectrometry and microwave digestion was used.[Result] The concentration curve was linear within the range of 0-0.80 μg/L the detection limits of Cd and Pb was 0.015 and 0.030 μg/L,respectively.The precision for elevenfold determination of Cd and of Pb at the 0.40 μg/L level were 1.8% and 2.3%（RSD）,respectively.Recoveries of 96.7%-98.2% for Cd and 104.6%-106.7% for Pb were obtained for two sugarcane samples and one certified reference material.[Conclusion] The proposed method has the advantages of simple operation,high sensitivity,and high efficiency;it was successfully used for determination of Cd and Pb in sugarcane samples.