The Growth Theorem for Strongly Starlike Mappings of Order α on Bounded Starlike Circular Domains

The authors obtain the growth and covering theorems for strongly starlike mappings of order α on bounded starlike circular domains.This kind of domain discussed is rather general,since the domain must be starlike if exists a normalized biholomorphic starlike mapping on it.

Application of pseudo-random frequency domain electromagnetic method in mining areas with strong interferences

Due to the strong electromagnetic interferences and human interference,traditional electromagnetic methods cannot obtain high quality resistivity data of mineral deposits in Chinese mines.The wide field electromagnetic method(WFEM),in which the pseudo-random signal is taken as the transmitter source,can extract high quality resistivity data in areas with sever interference by only measuring the electric field component.We use the WFEM to extract the resistivity information of the Dongguashan mine in southeast China.Compared with the audio magnetotelluric(AMT)method,and the controlled source audio-frequency magnetotelluric(CSAMT) method,the WFEM can obtain data with higher quality and simpler operations.The inversion results indicate that the WFEM can accurately identify the location of the main ore-body,which can be used for deep mine exploration in areas with strong interference.

Evaluation of strongly singular domain integrals for internal stresses in functionally graded materials analyses using RIBEM

An accurate evaluation of strongly singular domain integral appearing in the stress representation formula is a crucial problem in the stress analysis of functionally graded materials using boundary element method.To solve this problem,a singularity separation technique is presented in the paper to split the singular integral into regular and singular parts by subtracting and adding a singular term.The singular domain integral is transformed into a boundary integral using the radial integration method.Analytical expressions of the radial integrals are obtained for two commonly used shear moduli varying with spatial coordinates.The regular domain integral,after expressing the displacements in terms of the radial basis functions,is also transformed to the boundary using the radial integration method.Finally,a boundary element method without internal cells is established for computing the stresses at internal nodes of the functionally graded materials with varying shear modulus.

冀东金厂峪金矿剪切带控矿规律及找矿建议

冀东金厂峪金矿为典型受构造作用控制的矿床,金矿体主要产于NNE向脆-韧性片理化带内的强变形带之中,直接控矿构造为叠加于强变形带之上的NNE向燕山期脆性断裂构造。本文在详细的野外调查基础上进行了构造分期配套,建立了弱变形域控岩+强变形带赋矿的透镜体控矿模式,结合矿体赋存和矿化富集规律总结,提出了韧脆性片理化带深部、两侧次级平行构造等找矿方向。

电磁防护技术发展综述与展望

针对复杂电磁对抗环境中电子信息装备面临的强电磁环境威胁以及防护加固需求,对强电磁防护技术的发展现状进行了综述,并提出了强电磁系统级综合防护的发展展望。强电磁防护是为了保证电子信息装备在强电磁环境中免受损伤或损毁的技术手段,从电磁波的耦合途径分析了当前电磁防护的重点和难点,然后分别以限幅器技术、频率滤波技术、能量选择防护技术三个方面对前门防护技术的发展现状进行了分析总结,最后从新型屏蔽材料和防护器件两个方面对新型电磁防护技术进行了展望,并从前后门一体防护、场路一体防护、多域联合防护三个角度对系统级电磁防护进行了总结,为电子信息装备在复杂电磁环境下的电磁防护加固设计提供了支撑。

关于代数L-domain的一个刻画定理

引入了强core紧拓扑空间的概念,给出了代数L-domain的刻画定理,其主要结果是:偏序集D是代数L-domain当且仅当对每个强core紧拓扑空间X,函数空间[X→D]是代数L-domain.

基于知识图谱的浓香型白酒酿造微生物可视化分析

为了深入了解浓香型白酒酿造微生物领域的研究成果与研究进展,该研究基于中国知网数据库及Web of Science核心数据库,对该领域在2009—2022年中英文文献进行查阅与筛选。分别从年度发文量、关键词、作者及科研机构等方面,采用文献计量学的方法,对该领域1017篇中文文献及130篇英文文献进行知识图谱可视化分析。结果表明,浓香型酿造白酒微生物领域处于蓬勃发展阶段,随着时间的推移,发文数量及质量都在不断提升。研究热点集中于窖泥、微生物多样性、大曲、己酸菌、酒醅、风味物质、己酸乙酯。同时,该领域科研人员沟通密切,高校及科研机构与浓香型白酒企业间合作紧密。通过该文综合分析,为科研人员了解该领域研究方向及热点,开展学术合作及交流提供了参考。

ROPER-SUFFRIDGE EXTENSION OPERATOR ON A REINHARDT DOMAIN

Let pj ∈ N and pj≥ 1, j = 2, …, k, k ≥ 2 be a fixed positive integer. We introduce a Roper-Suffridge extension operator on the following Reinhardt domain ΩN ={z =（z1, z′2,…, z′k）′∈ C × C^n2×…× Cnk： ｜z1｜^2＋ ｜｜z2｜｜2^p2＋ … ＋ ｜｜zk ｜｜k^pk〈 1} given〈1} give by F（z）=（f（z1）＋f＇（z1）∑j=2 kPj（zj,（f＇（z1））1/p2 z2＇,…,（f＇（z1））1/pkzk＇）＇, where f is a normaljized biholomorphic function k（z） =（f（z1） ＋ f′（z1）=2 on the unit disc D, and for 2 ≤ j ≤ k, Pj ： C^nj→ C is a homogeneous polynomial of degree pj and zj =（zj1, …, zjnj）′∈ C^nj, nj ≥ 1, pj ≥ 1,｜｜zj｜｜j =（∑l=1 nj｜zjl｜^pj）1/pj. In this paper, some conditions for Pjare found under which the loperator p ｜zjl｜pj=1reserves the properties of almost starlikeness of order α, starlikeness of order αand strongly starlikeness of order α on ΩN, respectively.

A STRONG SOLUTION OF NAVIER-STOKES EQUATIONS WITH A ROTATION EFFECT FOR ISENTROPIC COMPRESSIBLE FLUIDS

We study the initial boundary value problem for the three-dimensional isentropic compressible Navier-Stokes equations in the exterior domain outside a rotating obstacle,with initial density having a compact support.By the coordinate system attached to the obstacle and an appropriate transformation of unknown functions,we obtain the three-dimensional isentropic compressible Navier-Stokes equations with a rotation effect in a fixed exterior domain.We first construct a sequence of unique local strong solutions for the related approximation problems restricted in a sequence of bounded domains,and derive some uniform bounds of higher order norms,which are independent of the size of the bounded domains.Then we prove the local existence of unique strong solution of the problem in the exterior domain,provided that the initial data satisfy a natural compatibility condition.

Non-stationary Buffeting Response Analysis of Long Span Suspension Bridge Under Strong Wind Loading

The non-stationary buffeting response of long span suspension bridge in time domain under strong wind loading is computed. Modeling method for generating non-stationary fluctuating winds with probabilistic model for non-stationary strong wind fields is first presented. Non-stationary wind forces induced by strong winds on bridge deck and tower are then given a brief introduction. Finally,Non-stationary buffeting response of Pulite Bridge in China,a long span suspension bridge,is computed by using ANSYS software under four working conditions with different combination of time-varying mean wind and time-varying variance. The case study further confirms that it is necessity of considering non-stationary buffeting response for long span suspension bridge under strong wind loading,rather than only stationary buffeting response.

空间—波数域二维强磁场及其梯度张量数值模拟研究

基于磁位泊松方程提出了一种空间—波数混合域二维数值模拟方法。该方法将二维强磁性体磁位满足的偏微分方程通过一维傅里叶变换转化为不同波数之间相互独立的常微分方程,即将二维数值模拟问题转换为一维数值模拟问题,并利用一维有限元法进行求解,可大大降低存储需求和计算量。对求得的强磁场利用紧算子进行迭代以获得高精度近似解。算法中保留垂向为空间域,可根据需求对网格进行灵活剖分,有利于复杂条件下的模拟。另外,不同波数之间常微分方程相互独立,具有较好的并行性。算法充分利用了傅里叶变换的快速性和迭代算法的稳定性,实现了强磁场及其梯度张量的二维数值模拟。设计三个模型(水平地形下的圆柱体模型、棱柱体模型及起伏地形模型)进行计算,对文中方法数值解与解析解、COMSOL软件所得的数值解进行对比,结果表明该算法计算速度快、精度高,适用于起伏地形条件下的数值计算。

基于双域联合编码和秘密共享的密文域可逆信息隐藏

针对如何提高可逆信息隐藏算法的安全性和嵌入容量的问题,提出了一种基于双域联合编码和密码反馈秘密共享的密文域可逆信息隐藏算法。首先,对图像进行中值边缘检测器(median-edge detector,MED)预测,计算最优水平l,并将像素分成可预测像素和不可预测像素;其次,使用双域联合编码分别在像素域和比特域上压缩辅助信息,以便提供更多的可嵌入空间;再次,使用密码反馈秘密共享技术将原始图像加密生成多个加密图像,并将辅助信息和多方的秘密数据嵌入到多个加密图像中;最后,根据提取的辅助信息,100%恢复秘密数据以及原始图像。实验结果表明,该算法显著提高了嵌入容量和安全性。

小波域强面波衰减方法研究

基于离散小波变换(DWT)阈值法压制面波适用于面波、反射波频带重叠的少数尺度范围去噪的特点,文中利用理论模型分析比较了四种阈值选取准则对DWT阈值方法压制面波结果的影响,并选出最佳准则。在此基础上首先使用改进的DWT阈值方法初步压制面波,然后再利用联合二维物理小波标架去噪(PWFD)方法压制剩余面波能量。理论记录和实际资料处理结果表明:DWT阈值去噪联合PWFD阈值去噪既可以较好地压制面波,又可以较好地实现有效信号的保真。该方法去噪效果优于F-K方法及其他方法。

强噪声条件下激光光斑图像预处理方法研究

为了研究强噪声光斑图像的抑噪方法,采用基于小波阈值法和形态学滤波的级联算法及小波域中值滤波法进行预处理,以信噪比、均方根误差和光强分布作为评估标准,并将处理效果与其他方法对比。结果表明:小波域中值滤波处理效果优于空域中值滤波;级联法的抑噪和光斑特征恢复效果更优于传统方法,其中对-2.0843dB的原低信噪比图像处理后的信噪比、均方根误差分别约为小波变换和空域中值滤波法的1.34、0.81倍和3.14、0.50倍;且原图像信噪比越低,其处理效果相对于传统方法的优越性越明显。

ON THE GENERALIZATIONS OF DENJOY-WOLFF THEOREM

We consider generalizations of Denjoy-Wolff theorem on strongly pseudoconvex domains. Beardon [3] gave a general Denjoy-Wolff theorem in hyperbolic domain in the complex plane. Our main results are generalizations of Beardon＇s result in a higher dimensional setting.

PTW整环的刻画

引入了PTW整环的概念,刻画了PTW整环的局部化性质,然后对PTW整环的拉回图进行了研究,证明了若RDTF是强M ilnor方图,则w-d im(R)=m ax{htTM+w-d im(D),w-d im(T)},最后通过例子说明了PTW整环不是TW整环.

基于Adaboost的视频文本定位

提出了一种基于Adaboost的视频文本定位的新方法。首先我们提取视频图像中的连通域,经过对视频文本区域分析,提取了视频文本的5类特征,然后利用这5类特征经过分类与回归决策树构造了Adaboost强分类器,最后将候选文本区域送入强分类器,得到正确的文本区域。实验结果表明本方法不仅对视频帧图像中字体、大小和颜色多变的文本具有很好的定位效果而且还实现了视频文本定位要求的快速性和准确性的特点。

小波方法及其力学应用研究进展

小波理论在进行信号处理与函数逼近时体现出非常独特的时频局部性与多分辨分析能力,小波基函数则可兼具正交性、紧支性、低通滤波与插值性等优良的数学性质,这均使得小波分析理论在计算数学与计算力学领域具有很大的应用潜力,也进一步为这些领域的突破性发展带来了新的契机.自20世纪90年代以来,大量的研究已经证明,基于小波理论的数值方法在微分方程求解中具有非常明显的优势,但与此同时也暴露出了一些由小波基函数本身与其特有逼近方式所造成的数值计算应用局限.为了促进小波理论在计算数学与力学领域的创新性应用,给研究人员提供新的研究视角,该文简要梳理了小波分析的发展背景以及基于小波理论的数值方法的研究历史,并着重讨论分析了后者所面临的问题,以及近年来针对这些问题中的基础性难题所取得的研究进展.这些总结与评述有望为后续进一步发展并完善基于小波理论的定量数学求解方法,以及拓展其在力学乃至广泛工程问题求解中的应用提供有意义的参考.

几乎Prüfer整环多项式环的维数和分式环

证明了如下2个结果:若R是几乎Prfer整环,则dimR[X1,…,Xn]=dimR+n;若R〈X〉■Rc〈X〉是根扩张,则R是几乎Prfer整环当且仅当R〈X〉是几乎Prfer整环.

用改进的变形参数法求解强参数激励Mathieu方程

为了研究大幅值参数激励M ath ieu方程,通过引入新的变换,将强参数激励系统转化为弱参数激励系统,利用改进的变形参数法求解无阻尼项的M ath ieu方程,分别得到具有π和2π方程的周期解和相应的过渡曲线,并利用过渡曲线得到方程的不稳定区域和稳定域.结果表明,该方法与文献[7]得到的过渡曲线基本吻合,通过数值法验证了用该方法得到稳定域比文献[7]的结果更为合理.