检索结果-南通市图书馆

Multispectral image compression and encryption method based on tensor decomposition in wavelet domain

在线全文

学校读者我要写书评

暂无评论

High Technology Letters 2024年第3期30卷 244-251页

作者： XU Dongdong du Limin du Yunlong Electronic Information Engineering College Changchun UniversityChangchun 130022P.R.China

Multispectral image compression and encryption algorithms commonly suffer from issues such as low compression efficiency,lack of synchronization between the compression and encryption proces-ses,and degradation of intrinsic image structure.A novel approach is proposed to address these ***,a chaotic sequence is generated using the Lorenz three-dimensional chaotic mapping to initiate the encryption process,which is XORed with each spectral band of the multispectral image to complete the initial encryption of the ***,a two-dimensional lifting 9/7 wavelet transform is applied to the processed ***,a key-sensitive Arnold scrambling technique is employed on the resulting low-frequency *** effectively eliminates spatial redundancy in the multispectral image while enhancing the encryption *** optimize the compression and encryption processes further,fast Tucker decomposition is applied to the wavelet sub-band *** effectively removes both spectral redundancy and residual spatial redundancy in the multispectral ***,the core tensor and pattern matrix obtained from the decomposition are subjected to entropy encoding,and real-time chaotic encryption is implemented during the encoding process,effectively integrating compression and *** results show that the proposed algorithm is suitable for occasions with high requirements for compression and encryption,and it provides valuable insights for the de-velopment of compression and encryption in multispectral field.

关键词： multi-spectral image compression encryption Lorenz three-dimensional chaotic mapping Arnold scrambling transform fast Tucker decomposition

Non-dimensional analysis on blast wave propagation in foam concrete:Minimum thickness to avoid stress enhancement

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第6期36卷 30-46页

作者： ya yang Xiangzhen Kong Qin Fang State Key Laboratory of Disaster Prevention&Mitigation of Explosion&Impact Army Engineering University of PLANanjing 210007JiangsuChina

Foam concrete is a prospective material in defense engineering to protect structures due to its high energy absorption capability resulted from the long plateau ***,stress enhancement rather than stress mitigation may happen when foam concrete is used as sacrificial claddings placed in the path of an incoming blast *** investigate this interesting phenomenon,a one-dimensional difference model for blast wave propagation in foam concrete is firstly proposed and numerically solved by improving the second-order Godunov *** difference model and numerical algorithm are validated against experimental results including both the stress mitigation and the stress *** difference model is then used to numerically analyze the blast wave propagation and deformation of material in which the effects of blast loads,stress-strain relation and length of foam concrete are *** particular,the concept of minimum thickness of foam concrete to avoid stress enhancement is ***,non-dimensional analysis on the minimum thickness is conducted and an empirical formula is proposed by curve-fitting the numerical data,which can provide a reference for the application of foam concrete in defense engineering.

关键词： Foam concrete Blast wave propagation Non-dimensional analysis Stress enhancement

Generalized Inverses and Units in a Unitary Ring

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2024年第4期40卷 1000-1014页

作者： Yu kun ZHOU Jian Long CHEN School of Mathematics Southeast UniversityNanjing 210096P.R.China

Let R be a unitary ring and a,b∈R with ab=*** find the 2/3 property of Drazin invertibility:if any two of a,b and a+b are Drazin invertible,then so is the third ***,we combine the 2/3 property of Drazin invertibility to characterize the existence of generalized inverses by means of *** applications,the need for two invertible morphisms used by You and Chen to characterize the group invertibility of a sum of morphisms is reduced to that for one invertible morphism,and the existence and expression of the inverse along a product of two regular elements are obtained,which generalizes the main result of Mary and Patricio(2016)about the group inverse of a product.

关键词： Leftπ-regular element stronglyπ-regular element group inverse Drazin inverse inverse along an element

A small D-A molecule with highly heat-resisting room temperature phosphorescence for white emission and anti-counterfeiting

在线全文

学校读者我要写书评

暂无评论

High-temperature wetting behavior between slag and refractory

结构化学 2024年第3期43卷 3-9页

作者： kun Zhang Ni Dan Dan-Dan Ren Ruo-Yu Zhang Xiaoyan Lu ya-Pan Wu Li-Lei Zhang Hong-Ru Fu Dong-Sheng Li College of Materials and Chemical Engineering China Three Gorges UniversityYichang443002PR China College of Chemistry and Chemical Engineering Luoyang Normal UniversityLuoyang471934PR China College of Chemistry and Chemical Engineering Luoyang Normal UniversityLuoyang471934PR China College of Materials and Chemical Engineering China Three Gorges UniversityYichang443002PR China

Achieving high heat-resisting room temperature phosphorescence(RTP)performance and robust white emission from pure small molecules is a meaningful but challenging ***,a simple donor-acceptor(D-A)molecule,9-(1H-benzotriazol-1-ylmethyl)-9H-carbazole(CzBtrz),was *** simple molecule not only exhibits multiple emissions including white light,thermally activated delayed fluorescence(TADF)and ultralong RTP with a lifetime of 988.54 ms at 545 nm,but also shows superhigh heat-resisting phosphorescence property which can maintain stability in a large temperature region from 77 to 350 K(ΔT=273 K),exceeding those of other RTP ***,this molecule shows the time-evolved dynamic *** experimental and theoretical an-alyses from CzBtrz crystal demonstrate that the intramolecular charge transfer(ICT)interaction and molecular stacking play an important role in the generation of ***,this work provides an efficient strategy to design ultrahigh heat-resistant RTP,ultralong RTP and single-phased white-light emitting materials.

关键词： Ultralong RTP TADF D-A molecule Heat-resisting White light

来源：评论

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第6期31卷 1304-1319页

作者： Yong-xin Wang ya-ge Li ya-bo Gao Zhong Huang Hai-jun Zhang The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina

Slag corrosion is one of the main factors of the damage of refractory,and its primary manifestations involve the melting of refractory in slag and the slag penetration into refractory,both of which are highly related to the wetting behavior between slag and *** high-temperature wettability could be characterized by parameters including the surface tension,adhesion work,and spreading coefficient of the slag on refractory surface,and it could be suppressed by altering the slag/refractory interface,thus resulting in an improved anti-corrosion *** this,the key knowledges of the slag corrosion,theory of wetting behavior and test of high-temperature contact angle were firstly ***,the major factors influencing the high-temperature slag wetting behavior were discussed based on the aspects of slag composition,refractory composition,and surface ***,the future research direction was proposed in this field.

关键词： High-temperature wetting Refractory Slag corrosion Surface tension

Effect of Ti_(p) Content on the Work Hardening and Softening Behavior of Mg-Zn-Ca Alloy

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2024年第3期37卷 551-560页

作者： Jin-Kai Zhang Cui-Ju Wang Yi-Dan Fan Chao Xu Kai-Bo Nie kun-kun Deng Shanxi Key Laboratory of Advanced Magnesium-Based Materials College of Materials Science and EngineeringTaiyuan University of TechnologyTaiyuan 030024China School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China

The Ti_(p)/ZX60 composites with different Ti_(p) contents were prepared by semi-solid stirring *** extrusion,the microstructure,work hardening and softening behavior of the Ti_(p)/ZX60 composites were analyzed compared with the ZX60(Mg-6Zn-0.2Ca)*** results showed that the addition of Ti_(p) could not only promote the nucleation of dynamic recrystallized(DRXed)grains,but also be propitious to the refinement of DRXed *** increasing Ti_(p) content,the size of DRXed grains decreased accompanied with increasing volume fraction of DRXed *** the Ti_(p) content increased to 15 vol.%,the average size and volume fraction of DRXed grains reached to~0.32μm and 93.2%,***,both the strength and elongation were improved by the addition of Ti_(p).With increasing content of Ti_(p),a substantial increase in the strength was achieved with little change in the ***,the elongation decreased sharply when the Ti_(p) content further increased to 15 vol.%.The addition of Ti_(p) led to an increase in the work hardening rate,which gradually increased with increasing Ti_(p) ***,the softening rate did not demonstrate the same tendency with increasing Ti_(p) *** the conventional ceramic particles,the Ti_(p) can be deformed in coordination with the matrix alloy,which imparted a higher softening rate to the matrix *** though the softening rate improved as the Ti_(p) content increased from 5 to 10 vol.%,it dropped deeply as the Ti_(p) content increased to 15 vol.%owing to the fracture of Ti_(p) during extrusion.

关键词： Titanium particle content Particle reinforced magnesium matrix composites Work hardening Softening behavior Mechanical properties

Cyclic Gradient Methods for Unconstrained Optimization

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of the Operations Research Society of China 2024年第3期12卷 809-828页

作者： ya Zhang Cong Sun School of Science Beijing University of Posts and TelecommunicationsBeijing100876China

Gradient method is popular for solving large-scale *** this work,the cyclic gradient methods for quadratic function minimization are extended to general smooth unconstrained optimization *** with nonmonotonic line search,we prove its global ***,the proposed algorithms have sublinear convergence rate for general convex functions,and R-linear convergence rate for strongly convex *** experiments show that the proposed methods are effective compared to the state of the arts.

关键词： Gradient method Unconstrained optimization Nonmonotonic line search Global convergence

Manganese oxide and derivative-modified materials in advanced oxidation processes:A review of modification enhancement and activation mechanisms

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2024年第3期35卷 40-51页

作者： Si Sun Shuang Song Shuai yang Yong-Li He yang Shi Peng Zhou Zhao-kun Xiong yang Liu Heng Zhang Ye du Chuan-Shu He Bo Lai State Key Laboratory of Hydraulics and Mountain River Engineering College of Architecture and EnvironmentSichuan UniversityChengdu 610065China Sino-German Centre for Water and Health Research Sichuan UniversityChengdu 610065China Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of ChinaSichuanChengdu 610054China

Manganese oxides(MNO_(x)),as low-toxicity and high-abundance catalysts,have been demonstrated to hold great promise for application in advanced oxidation processes(AOPs).However,further application of this material is restricted due to its unsatisfactory oxidant activation ***,recently remarkable research on deep activation mechanisms and modification of MNO_(x)have been undertaken to improve its ***,modification enhancement mechanisms of MNO_(x)to efficiently degrade various organic contaminants were discussed and highlighted,including metal doping,coupling with other metal oxides,composite with carbonaceous material,and compounding with other *** activation mechanisms of different MNO_(x)and derivative-modified material(such as doped MNO_(x),metal oxide-MNO_(x)hybrids,and MNO_(x)-carbonaceous material hybrids)were summarized in great details,which was specifically categorized into both radical and non-radical *** effects of pH,inorganic ions,and natural organic matter on degradation reactions are also ***,future research directions and perspectives are presented to provide a clear interpretation on the MNO_(x)initiated AOPs.

关键词： Manganese oxide Derivative-modified materials Modification enhancement mechanisms Advanced oxidation process Activation mechanism

Sequential Propagation of Chaos for Mean-Field BSDE Systems

在线全文

学校读者我要写书评

暂无评论

Chinese Annals of Mathematics,Series B 2024年第1期45卷 11-40页

作者： Xiaochen LI Kai du Shanghai Center for Mathematical Sciences Fudan UniversityShanghai 200433China. Shanghai Artificial Intelligence Laboratory 701 Yunjin RoadShanghai 200433China

A new class of backward particle systems with sequential interaction is proposed to approximate the mean-field backward stochastic differential *** is proven that the weighted empirical measure of this particle system converges to the law of the McKean-Vlasov system as the number of particles *** on the Wasserstein met-ric,quantitative propagation of chaos results are obtained for both linear and quadratic growth ***,numerical experiments are conducted to validate our theoretical results.

关键词： Backward propagation of chaos Particle system Sequential interaction McKean-Vlasov BSDE Convergence rate