Thermostable Broad Band Polarizing PVA-Film: Theoretical and Experimental Investigations

In the present work, for the first time on the basis ofpoly （vinyl alcohol） （PVA）, 2- （4-dimethylaminostyryl）-l-ethylquinolinium iodide （quinaldine red （QR）） and trisodium （4E）-5-oxo- 1-（4-sulfonatophenyl）-4-[（4-sulfonatophenyl）hydrazono]-3 pyrazolecarboxylate （tartrazine （T））, thermostable polarizing film in a wide range of spectra （λmax=394-511 nm） with polarization efficiency （PE） = 98% in absorption maximum and stretching degree （Rs） = 3.5 was developed. The basic spectral-polarization parameters （polarization efficiency and transmittance） of oriented colored PVA-films were measured and discussed. During the work it was found that oriented PVA-films are the phenomenon of anisotropy of thermal conductivity （λ｜/λ⊥）. It is a very important parameter for the development of thermostable PVA-polarizing films. For the first time quantum-chemical calculations using density functional theory （DFT） approach for structural analysis and electronic spectrum of the QR were carried out via the B3LYP/dgdzvp and TDB3LYP/dgdzvp methods. Interpretation of absorption strips in visible region of spectrum was also reported. The excitation energies, electronic transitions and oscillator strengths for the studied structures have also been calculated （B3LYP/dgdzvp）. The NBO analysis and Mulliken atomic charges of the QR were carried out.

Higher degree moment tensor inversion of Mani earthquake using far-field broadband recording

Breakthrough point source model, extended earthquake source model is used to calculate more seismic source parameters in this paper. We express seismic source using higher degree moment tensors, to reduce a Iarge number terms originally presenting in higher degree moment tensor representation, Haskell rupture model is used. We in verted the source parameters of Mani earthquake in Tibet using broad-band body wave of 32 stations of Global Seismograph Network (GSN), the results show that it is a strike-slip fault, rupture direction is 75°, rupture duration is 19 s, the fault plan is φ=77°， δ5=88°, A=0°, the auxiliare plane is φ=347°, δ=90°, k=178°, and the fault dimension is 47 km×28 km. These results will give new quantitative data for earth dynamics and have practical meaning for seismic source tomography research.

Study on guided-mode resonance characteristic of multilayer dielectric grating with broadband and wide using-angle

Guided-mode resonance in a diffraction band of multilayer dielectric gratings may lead to a catastrophic result in laser system, especially in the ultrashort pulse laser system, so the inhibition of guided-mode resonance is very important. In this paper the characteristics of guided-mode resonance in multilayer dielectric grating are studied with the aim of better understanding the physical process of guided-mode resonance and designing a broadband multilayer dielectric grating with no guided-mode resonance. By employing waveguide theory, all guided-wave modes appearing in multilayer dielectric grating are found, and the incident conditions, separately, corresponding to each guided-wave mode are also obtained. The electric field enhancement in multilayer dielectric grating is shown obviously. Furthermore, from the detailed analyses on the guided-mode resonance conditions, it is found that the reduction of the grating period would effectively avoid the appearing of guided-mode resonance. And the expressions for calculating maximum periods, which ensure that no guided-mode resonance occurs in the requiring broad angle or wavelength range, are first reported. The above results calculated by waveguide theory and Fourier mode method are compared with each other, and they are coincident completely. Moreover, the method that relies on waveguide theory is more helpful for understanding the guided-mode resonance excited process and analyzing how each parameter affects the characteristic of guided-mode resonance. Therefore, the effects of multilayer dielectric grating parameters, such as period, fill factor, thickness of grating layer, et al., on the guided-mode resonance characteristic are discussed in detail based on waveguide theory, and some meaningful results are obtained.

Study of characteristics of long-period ground motion response spectra by using broad-band records of the Chinese Digital Seismograph Network

Broad band and very broad band (BB and VBB) records of Chinese Digital Seismograph Network (CDSN) from 65 earthquakes are used to calculate the horizontal relative displacement, relative velocity and absolute acceleration response spectra with critical damping ratio ζ =0.005, 0.01, 0.02, 0.05 and 0.10, respectively. The results show that it is insufficient to obtain the credible characteristics of long-period ground motion response spectra only with the common ground acceleration records in engineering, while the broad band records of CDSN, as an important supplementary to ground acceleration records, can be used to study the characteristics of long-period ground motion response spectra.

Neoproterozoic Banded Iron Formation in the Central Tianshan, NW China: The Shalong Example

Objective Banded Iron Formations （BIFs） are ferruginous chemical sedimentary rocks that precipitated throughout the Precambrain, which constitute the most important iron resources in the world. The majority of BIFs were developed in the Neoarchean and early Paleoproterozoic periods （3.2-1.8 Ga）, which are well known and have been mined for centuries. Another type of the BIFs which was formed in the Neoproterozoic period （0.85-0.7 Ga） is much smaller in scale but widespread on the Earth and record important information of the evolution of the Earth. The Neoarchean and Paleoproterozoic BIFs have been well studied and understood, while few detailed studies on Neoproterozoic BIFs have been made, and only a few modem geochronology studies were carried out on Neoproterozoic BIFs.

Fractal Modeling of Sphalerite Banding in Jinding Pb-Zn Deposit, Yunnan, Southwestern China

Sphalerite banding is a common texture in Jinding （金顶） Pb-Zn deposit, Yunnan （云南）, southwestern China. The frequency distribution and irregularity of sphalerite grains observed in the bandings are characterized quantitatively by fractal models. Fractal dimensions calculated by several fractal models including box-counting model, perimeter-area （P-A） model, and number-area （N-A） model show the gradual change from outer banding to inner banding, indicating a decrease in area percentage, in irregularity, in shape and in grain size, and an increase in the numbers of grains. These results may imply an inward growth of sphalerite during mineralization, and self-organization properties are involved in the nonlinear process of mineralization.

Broad Band Microstrip Patch Antenna Based on Foam-Filled and One Open Slot on Backward of Radiating Layer

A broadband microstrip patch antenna, loaded E-U-shaped open slot on backward of radiating layer is proposed and experimentally investigated. The antenna employs a foam-filled dielectric substrate, whose dielectric constant is within the lower end of the range. The proposed antenna has been designed for electromagnetic analysis including the impedance bandwidth, reflection coefficient, radiation pattern, and antenna gain. The open slot is loaded on the back radiated layer, which is perpendicular to the radiating edge of the oblong microstrip patch component, where the symmetric line feed is selected. This new technique used to increase the bandwidth and the gain of antenna through increasing current path by slot location, width and length on backward of radiating Layer. The main structure in this research was a single microstrip patch antenna planar with three layers operating at two resonant frequencies 4.440 GHz and 5.833 GHz. All the simulated results are confirmed by two packages of electromagnetism simulation. An impedance bandwidth (S11 ≤ ?10 dB) up to about 41.03% and 30.61% is achieved by individually optimizing its parameters. The antenna exhibits nearly stable radiation pattern with a maximum gains of 8.789 dBi and 9.966 dBi, which is suitable for Wi-Fi Band, satellite communications, and wireless presented. Whereas the results before this design that we have a proof of publication are 36.17% and 28.43%.

Broad Prospects for Transnational Companies in China

China’s deepening economic reform has started a new upsurge of development, providing a broad investment market for foreign industrial enterprises and finance circles, especially those transnational companies with advantages of high technology and scale. Asia and the Pacific are the focal point for world economic

A tunable dual-broad-band branch-line coupler utilizing composite right/left-handed transmission lines

A tunable dual-broad-band branch-line coupler (BLC) utilizing composite right/left-handed (CRLH) transmission lines is presented. Two λ/4 segments consisting of CRLH transmission lines are added to each port to broaden the dual bands of the branch-line coupler. Numerical simulation and optimal design of the novel coupler are presented. The dual bands of the novel coupler are tunable and broad. The 1-dB bandwidth of each pass band is more than 16% of the central frequency.

A Broadband T/R Front-End of Millimeter Wave Holographic Imaging

A broadband T/R frond-end of active holographic imaging system is presented. Compact autodyne mode circuit structure front-end is adopted to achieve higher signal to noise ratio and higher reliability, which is beneficial to the after-end imagining. The factors that influence the dynamic range and the transverse resolution ratio of holographic imaging system have been analyzed. Wide-band oscillator, wide-band low noise amplifier and the tapered slot antennas are implemented to meet the requirements of the holographic imagining system. According to the measured results, the output power is uniform in the broadband working frequency. The sub-harmonic suppression is better than 25 dBc from the frequency of 28 GHz to 33 GHz. The isolation between antennas channel is greater than 20 dB. The experimental result shows that the performance of the front-end is good enough to meet the needs of active millimeter-wave holographic imaging system.

Multiscale Combined Action and Disturbance Characteristics of Pre-summer Extreme Precipitation Events over South China

The dominant frequency modes of pre-summer extreme precipitation events(EPEs)over South China(SC)between1998 and 2018 were investigated.The 67 identified EPEs were all characterized by the 3-8-d(synoptic)frequency band.However,multiscale combined modes of the synoptic and three low-frequency bands[10-20-d(quasi-biweekly,QBW);15-40-d(quasi-monthly,QM);and 20-60-d(intraseasonal)]accounted for the majority(63%)of the EPEs,and the precipitation intensity on the peak wet day was larger than that of the single synoptic mode.It was found that EPEs form within strong southwesterly anomalous flows characterized by either lower-level cyclonic circulation over SC or a deep trough over eastern China.Bandpass-filtered disturbances revealed the direct precipitating systems and their life cycles.Synoptic-scale disturbances are dominated by mid-high latitude troughs,and the cyclonic anomalies originate from downstream of the Tibetan Plateau(TP).Given the warm and moist climate state,synoptic-scale northeasterly flows can even induce EPEs.At the QBW and QM scales,the disturbances originate from the tropical Pacific,downstream of the TP,or mid-high latitudes(QBW only).Each is characterized by cyclonic-anticyclonic wave trains and intense southwesterly flows between them within a region of large horizontal pressure gradient.The intraseasonal disturbances are confined to tropical regions and influence SC by marginal southwesterly flows.It is concluded that low-frequency disturbances provide favorable background conditions for EPEs over SC and synoptic-scale disturbances ultimately induce EPEs on the peak wet days.Both should be simultaneously considered for EPE predictions over SC.

网络基础设施建设对包容性绿色增长的影响——基于“宽带中国”战略的准自然实验

推动包容性绿色增长是解决我国低碳发展目标与经济增长矛盾的重要途径。本文基于2010~2022年我国地级市层面数据,利用熵权TOPSIS法从多个维度测算了289个地级市的包容性绿色增长水平,采用多期双重差分模型探究网络基础设施建设对包容性绿色增长的影响及传导机制。研究结果表明:(1)网络基础设施建设能够有效促进包容性绿色增长水平的提升;(2)网络基础设施建设对于非资源型城市包容性绿色增长效应显著高于资源型城市;(3)网络基础设施建设能够通过提高制造业集聚水平、促进产业结构升级、鼓励技术创新进一步提升包容性绿色增长水平。本文在进一步完善包容性绿色增长的现有分析框架基础上,为政府推进“宽带中国”战略实施、缩小区域发展差距以及促进经济高质量发展提供政策启示。

一种S波段雷达通信电子战多功能宽带DAM的设计

本文创新性地提出了一种S波段多功能宽带DAM,首先介绍了该型DAM的顶层架构设计,接着介绍了各个功能组成模块的设计过程,最后给出了该型DAM的指标实现情况。该型DAM可以分时实现雷达、通信及电子战功能,最大瞬时带宽可达200MHz,支持任意波形产生,在多功能综合射频系统中具有良好的应用前景。

一种双简支―悬臂梁反共振隔振器设计分析与试验

[目的]为探究三元件型反共振隔振器的实现形式,提出一种由一根悬臂端含质量块的双简支-悬臂梁与一根双支撑梁所组成的机械装置(BAVI)。[方法]首先,分析双简支-悬臂梁的动态特性,推导其阻抗方程;然后,根据驱动点阻抗函数综合其低阶模型是单惯容与单弹簧二元件的串联结构,并解析低阶模型的等效参数;最后,通过装置试件设计与试验,验证其反共振特性和理论方法有效性,并在此基础上分析装置刚度特性及不同阻尼形式的效果。[结果]结果表明,当跨度比共振隔振器结构,具有“高静低动”刚度特性;在双简支-悬臂梁上采取阻尼措施后,可实现隔振区传递率以最大速率衰减的同时抑制共振峰的效果。[结论]所提机械装置证明了三元件型反共振隔振器的可实现性,提供了一种简易可行的工程结构。

一种宽带宽波束圆极化微带天线的设计

本文设计了一款宽带宽波束圆极化微带天线。天线采用堆叠的双层圆贴片结构,结合四点顺序旋转馈电方式,实现了宽带圆极化辐射性能;在叠层圆贴片周边加载垂直接地金属柱环形阵,利用波束引向作用和等效零模谐振特性,在大带宽范围内实现了半功率波束宽度(HPBW)的有效展宽,并保证宽带宽波束内的圆极化辐射性能。对天线进行了加工、测试。实测结果表明,S 11小于-10 dB的阻抗带宽(4.54 GHz~11.50 GHz)为87%,覆盖了期望的应用工作频带6 GHz~10 GHz;轴比小于3 dB的带宽达到了33.1%(6.71 GHz~9.36 GHz);HPBW在6 GHz~8 GHz范围内接近100°,在整个带宽内均超过75°;除了9.5 GHz以上频段,工作频带内的6 dB轴比波束宽度覆盖范围都接近200°,表明天线在宽带和宽波束内具有良好的圆极化性能。

中小型土壤动物群落对华西雨屏区常绿阔叶林氮沉降的响应

【目的】掌握氮沉降对土壤动物群落特征的影响,为亚热带常绿阔叶林的可持续发展提供数据支撑。【方法】自2014年1月起在华西雨屏区进行模拟氮沉降试验,于2021年7月开始进行为期1年的季度采样试验。设置对照0 g/(m^(2)·a)、低氮5 g/(m^(2)·a)和高氮15 g/(m^(2)·a)3个施氮水平,采用干生漏斗对中小型土壤动物进行分离鉴定,研究土壤动物群落特征。【结果】试验共捕获中小型土壤动物8 390只,属2门5纲8目40科,优势类群为弹尾目等节(虫兆)科,占中小型土壤动物总密度的31.05%。土壤动物群落垂直分布表现出明显的表聚性特征。多样性特征均无显著变化。土壤动物功能类群以菌食性、腐食性和捕食性土壤动物为主。【结论】模拟氮沉降在一定程度降低了中小型土壤动物平均密度,增加了土壤动物类群数。氮沉降浓度的增加,不利于中小型土壤动物的生存发展。

基于尖脉冲子波的高分辨率气枪震源设计

高分辨率气枪震源的设计是海上油气资源勘探的关键环节之一。分析震源子波形态与分辨率的关系,确定以尖脉冲子波作为震源优化的依据。基于非理想气体条件气枪子波模型对不同容量气枪的子波进行模拟,定量分析了不同容量气枪的主脉冲峰值及达到峰值的时间。提出通过调整阵列中不同容量气枪延迟激发时间和沉放深度,使阵列中各气枪主脉冲峰值同相叠加以构建尖脉冲子波的方法。在常规阵列的基础上设计了两种尖脉冲气枪阵列,并与常规阵列进行子波和频谱对比,结果表明:水深为20 m的条件下,基于尖脉冲子波设计的阵列较常规阵列虚反射效应和陷波点效应的压制效果更好;主峰值、峰-峰值和初泡比分别增大11.6%,12.4%,16.4%;兼顾了高频和低频,有效频宽增大14.5%;能谱展布范围更广,能量下传能力更强,提高了信噪比和分辨率。

基于人工表面等离子激元的宽带谐振天线

针对传统微带和介质谐振天线(DRA)带宽较窄和尺寸较大的问题,提出了一种基于人工表面等离子激元波导谐振腔的宽带天线。该天线人工表面等离子激元(SSPPs)波导由对称的H型单元结构组成,谐振腔由同轴探针馈电,利用波导单元偶模和奇模两种模式的色散特性,实现了天线带宽的显著增大。该天线工作频段为8.8~12.4 GHz,相对带宽为33.9%。在工作频带内,天线的辐射效率大于92%,最大增益达到了6.8 dBi。此外,天线为低剖面结构,整体尺寸较小,结构简单,利于各种无线通信和传感系统的集成。

基于改进T-B法的宽带高斯过程疲劳损伤分析

针对宽带高斯随机应力过程造成的疲劳损伤问题,本文提出一种基于改进Tovo-Benasciutti(T-B)法的疲劳损伤频域分析方法。通过不同参数形式的功率谱进行时域的疲劳损伤分析,针对T-B法中的关键参数bTB提出一个新的非线性函数模型。与原T-B法相比,新提出的函数模型bMTB可以考虑S-N曲线斜率参数m的影响,并以此为基础提出基于改进T-B法的疲劳损伤分析方法。以时域的雨流计数法结果作为基准,分别采用参数化功率谱和真实响应谱进行数值试验,并与现有的多种宽带高斯疲劳损伤分析方法进行对比,验证本文所提出的改进T-B法的准确性和适用性。