A medical image encryption is proposed based on the Fisher-Yates scrambling,filter diffusion and S-box substitution.First,chaotic sequence associated with the plaintext is generated by logistic-sine-cosine system,whic...A medical image encryption is proposed based on the Fisher-Yates scrambling,filter diffusion and S-box substitution.First,chaotic sequence associated with the plaintext is generated by logistic-sine-cosine system,which is used for the scrambling,substitution and diffusion processes.The three-dimensional Fisher-Yates scrambling,S-box substitution and diffusion are employed for the first round of encryption.The chaotic sequence is adopted for secondary encryption to scramble the ciphertext obtained in the first round.Then,three-dimensional filter is applied to diffusion for further useful information hiding.The key to the algorithm is generated by the combination of hash value of plaintext image and the input parameters.It improves resisting ability of plaintext attacks.The security analysis shows that the algorithm is effective and efficient.It can resist common attacks.In addition,the good diffusion effect shows that the scheme can solve the differential attacks encountered in the transmission of medical images and has positive implications for future research.展开更多
The interdiffusion coefficients in Al_(0.2)CoCrFeNi,CoCrCu_(0.2)FeNi,and CoCrFeMn_(0.2)Ni high-entropy alloys were efficiently determined by combining diffusion couple experiments and high-throughput determination of ...The interdiffusion coefficients in Al_(0.2)CoCrFeNi,CoCrCu_(0.2)FeNi,and CoCrFeMn_(0.2)Ni high-entropy alloys were efficiently determined by combining diffusion couple experiments and high-throughput determination of interdiffusion coefficients(HitDIC)software at 1273−1373 K.The results show that the addition of Al,Cu,and Mn to CoCrFeNi high-entropy alloys promotes the diffusion of Co,Cr,and Fe atoms.The comparison of tracer diffusion coefficients indicates that there is no sluggish diffusion in tracer diffusion on the thermodynamic temperature scale for the present Al_(0.2)CoCrFeNi,CoCrCu_(0.2)FeNi,and CoCrFeMn_(0.2)Ni high-entropy alloys.The linear relationship between diffusion entropy and activation energy reveals that the diffusion process of atoms is unaffected by an increase in the number of components as long as the crystal structure remains unchanged.展开更多
Recently,diffusion models have emerged as a promising paradigm for molecular design and optimization.However,most diffusion-based molecular generative models focus on modeling 2D graphs or 3D geom-etries,with limited ...Recently,diffusion models have emerged as a promising paradigm for molecular design and optimization.However,most diffusion-based molecular generative models focus on modeling 2D graphs or 3D geom-etries,with limited research on molecular sequence diffusion models.The International Union of Pure and Applied Chemistry(IUPAC)names are more akin to chemical natural language than the simplified molecular input line entry system(SMILES)for organic compounds.In this work,we apply an IUPAC-guided conditional diffusion model to facilitate molecular editing from chemical natural language to chemical language(SMILES)and explore whether the pre-trained generative performance of diffusion models can be transferred to chemical natural language.We propose DiffIUPAC,a controllable molecular editing diffusion model that converts IUPAC names to SMILES strings.Evaluation results demonstrate that our model out-performs existing methods and successfully captures the semantic rules of both chemical languages.Chemical space and scaffold analysis show that the model can generate similar compounds with diverse scaffolds within the specified constraints.Additionally,to illustrate the model’s applicability in drug design,we conducted case studies in functional group editing,analogue design and linker design.展开更多
The excellent irradiation resistance,high strength and plasticity exhibited by high-entropy alloys(HEAs)make it candidate for engin-eering applications.Diffusion bonding of Al_(0.3)CoCrFeNi single-phase HEAs was carri...The excellent irradiation resistance,high strength and plasticity exhibited by high-entropy alloys(HEAs)make it candidate for engin-eering applications.Diffusion bonding of Al_(0.3)CoCrFeNi single-phase HEAs was carried out using electric-assisted diffusion bonding(EADB),and the effect of bonding temperature on the evolution of the interfacial microstructure and the mechanical properties was investigated.The results indicate that as the bonding temperature increases,the pores at the interface gradually decrease in size and undergo closure.The electric current significantly promotes the pore closure mechanism dominated by plastic deformation at the diffusion interface and promotes the recrystallisation behavior at the interface,and the fracture mode changes from intergranular fracture at the interface to jagged fracture along the grains spanning the weld parent material.Due to the activation effect of EADB,higher-strength diffusion bonding of high-entropy alloys can be achieved at the same temperature compared with the conventional hot-pressure diffusion bonding(HPDB)process.展开更多
This study aims to develop a chloride diffusion simulation method that considers the hydration microstructure and pore solution properties during the hydration of tricalcium silicate(C3S).The method combines the hydra...This study aims to develop a chloride diffusion simulation method that considers the hydration microstructure and pore solution properties during the hydration of tricalcium silicate(C3S).The method combines the hydration simulation,thermodynamic calculation,and finite element analysis to examine the effects of pore solution,including effect of electrochemical potential,effect of chemical activity,and effect of mechanical interactions between ions,on the chloride effective diffusion coefficient of hydrated C3S paste.The results indicate that the effect of electrochemical potential on chloride diffusion becomes stronger with increasing hydration age due to the increase in the content of hydrated calcium silicate;as the hydration age increases,the effect of chemical activity on chloride diffusion weakens when the number of diffusible elements decreases;the effect of mechanical interactions between ions on chloride diffusion decreases with the increase of hydration age.展开更多
Particle transport is a fundamental aspect of various systems,from artificial to biological.A common assumption is that particle motion follows Markovian(memoryless)processes in the absence of interaction between part...Particle transport is a fundamental aspect of various systems,from artificial to biological.A common assumption is that particle motion follows Markovian(memoryless)processes in the absence of interaction between particles.However,hydrodynamic memory and the interaction between particles are ubiquitous,leaving many fundamental questions unanswered regarding transport of interacting particles involving hydrodynamic drag in corrugated channels,as described by the fractional Langevin equation.This study examines the hydrodynamic transport of interacting non-Brownian particles moving within a corrugated channel.We propose a method that relies on factors such as temperature,the driving force to alternate between no transport and finite net transport.Of importance is to note that the absence of transport results from the clogging,while the transport consists of collective motion and independent motion.The transport systems investigated in this work suggest the potential for sensor functionality within the system.Our findings may prove valuable for exploring the transport with hydrodynamic memory in various fields,including biology,physics,and chemistry.展开更多
We study the two-dimensional(2D)Cauchy problem of nonhomogeneous Boussinesq system for magnetohydrodynamics convection without heat diffusion in the whole plane.Based on delicate weighted estimates,we derive the globa...We study the two-dimensional(2D)Cauchy problem of nonhomogeneous Boussinesq system for magnetohydrodynamics convection without heat diffusion in the whole plane.Based on delicate weighted estimates,we derive the global existence and uniqueness of strong solutions.In particular,the initial data can be arbitrarily large and the initial density may contain vacuum states and even have compact support.展开更多
The grain boundary diffusion process(GBDP)has proven to be an effective method for enhancing the coercivity of sintered Nd-Fe-B magnets.However,the limited diffusion depth and thicker shell struc-ture have impeded the...The grain boundary diffusion process(GBDP)has proven to be an effective method for enhancing the coercivity of sintered Nd-Fe-B magnets.However,the limited diffusion depth and thicker shell struc-ture have impeded the further development of magnetic properties.Currently,the primary debates re-garding the mechanism of GBDP with Tb revolve around the dissolution-solidification mechanism and the atomic substitution mechanism.To clarify this mechanism,the microstructure evolution of sintered Nd-Fe-B magnets during the heating process of GBDP has been systematically studied by quenching at different tem peratures.In this study,it was found that the formation of TbFe_(2) phase is related to the dis-solution of _(2)Fe_(14)B grains during GBDP with Tb.The theory of mixing heat and phase separation further confirms that the Nd_(2)Fe_(14)B phase dissolves to form a mixed phase of Nd and TbFe_(2),which then solidifies into the(Nd,Tb)_(2)Fe_(14)B phase.Based on the discovery of the TbFe_(2) phase,the dissolution-solidification mechanism is considered the primary mechanism for GBDP.This is supported by the elemental content of the two typical core-shell structures observed.展开更多
针对现有无数据模型窃取攻击技术在有限的查询预算下难以拟合原始训练集分布,进而影响对目标模型决策边界拟合效果问题,提出了一种基于Stable Diffusion的模型窃取攻击方法(Model Extraction Attack Based on Stable Diffusion,MEASD)....针对现有无数据模型窃取攻击技术在有限的查询预算下难以拟合原始训练集分布,进而影响对目标模型决策边界拟合效果问题,提出了一种基于Stable Diffusion的模型窃取攻击方法(Model Extraction Attack Based on Stable Diffusion,MEASD).利用预训练的Stable Diffusion生成训练数据可能涵盖多个域,并包含大量非判别性样本,设计了ILAF方法以优化Stable Diffusion生成的数据品质.将高质量合成数据的原始样本与由对抗样本生成器生成的对抗样本组成替代训练集.由DPA模块组合的替代模型基于替代训练集拟合目标模型的决策边界.实验结果表明,在四个主流的基准数据集上与EBFA和DMEAE方法相比,所提的MEASD方法能够将目标模型决策边界的拟合程度提高至84%,对目标模型的黑盒对抗攻击成功率超过68%,并且查询预算较低.MEASD方法能够有效地提升目标模型决策边界拟合效果及攻击成功率.展开更多
The transient liquid-phase(TLP)diffusion bonding of GH5188 with a BNi-5 interlayer was focused on.Parameters were chosen and optimized for GH5188 alloy according to the TLP joining mechanism.The microstructure evoluti...The transient liquid-phase(TLP)diffusion bonding of GH5188 with a BNi-5 interlayer was focused on.Parameters were chosen and optimized for GH5188 alloy according to the TLP joining mechanism.The microstructure evolution and mechanical properties of the joints were studied.Results show that the relatively complete isothermal solidification zone(ISZ)ensures a reliable connection of the base metal(BM).Within the temperature range of 1110–1190°C,higher bonding temperatures can widen ISZ and promote joint composition homogenization,thus improving mechanical properties.However,the increase in precipitated phase has an adverse effect on the mechanical properties of the joint.The maximum shear strength,reaching 482 MPa,is achieved at 1130°C,representing 84.6%of BM strength.Within the pressure range of 5–15 MPa,both precipitated phases in adiabatic solidification zone(ASZ)and voids generated by partial melting increase.On the contrary,their sizes decrease significantly under higher bonding pressure,resulting in an upward trend in alloy mechanical properties.The maximum shear strength of 490 MPa is attained at a bonding pressure of 15 MPa.The joint exhibits a typical mixed fracture pattern,with the small brittle M_(23)C_(6) phase and voids significantly impacting mechanical properties.Nano-indentation tests indicate that ASZ is a potential source of cracks.展开更多
文摘A medical image encryption is proposed based on the Fisher-Yates scrambling,filter diffusion and S-box substitution.First,chaotic sequence associated with the plaintext is generated by logistic-sine-cosine system,which is used for the scrambling,substitution and diffusion processes.The three-dimensional Fisher-Yates scrambling,S-box substitution and diffusion are employed for the first round of encryption.The chaotic sequence is adopted for secondary encryption to scramble the ciphertext obtained in the first round.Then,three-dimensional filter is applied to diffusion for further useful information hiding.The key to the algorithm is generated by the combination of hash value of plaintext image and the input parameters.It improves resisting ability of plaintext attacks.The security analysis shows that the algorithm is effective and efficient.It can resist common attacks.In addition,the good diffusion effect shows that the scheme can solve the differential attacks encountered in the transmission of medical images and has positive implications for future research.
基金supported by the National Natural Science Foundation of China(No.52374372)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.23KJB430042)+3 种基金the Jiangsu Province Large Scientific Instruments Open Sharing Autonomous Research Filing Project,China(No.TC2023A037)the Yangzhou City−Yangzhou University Cooperation Foundation,China(No.YZ2022183)High-end Talent Support Program of Yangzhou University,China,Qinglan Project of Yangzhou University,ChinaLvyangjinfeng Talent program of Yangzhou,China.
文摘The interdiffusion coefficients in Al_(0.2)CoCrFeNi,CoCrCu_(0.2)FeNi,and CoCrFeMn_(0.2)Ni high-entropy alloys were efficiently determined by combining diffusion couple experiments and high-throughput determination of interdiffusion coefficients(HitDIC)software at 1273−1373 K.The results show that the addition of Al,Cu,and Mn to CoCrFeNi high-entropy alloys promotes the diffusion of Co,Cr,and Fe atoms.The comparison of tracer diffusion coefficients indicates that there is no sluggish diffusion in tracer diffusion on the thermodynamic temperature scale for the present Al_(0.2)CoCrFeNi,CoCrCu_(0.2)FeNi,and CoCrFeMn_(0.2)Ni high-entropy alloys.The linear relationship between diffusion entropy and activation energy reveals that the diffusion process of atoms is unaffected by an increase in the number of components as long as the crystal structure remains unchanged.
基金supported by the Yonsei University graduate school Department of Integrative Biotechnology.
文摘Recently,diffusion models have emerged as a promising paradigm for molecular design and optimization.However,most diffusion-based molecular generative models focus on modeling 2D graphs or 3D geom-etries,with limited research on molecular sequence diffusion models.The International Union of Pure and Applied Chemistry(IUPAC)names are more akin to chemical natural language than the simplified molecular input line entry system(SMILES)for organic compounds.In this work,we apply an IUPAC-guided conditional diffusion model to facilitate molecular editing from chemical natural language to chemical language(SMILES)and explore whether the pre-trained generative performance of diffusion models can be transferred to chemical natural language.We propose DiffIUPAC,a controllable molecular editing diffusion model that converts IUPAC names to SMILES strings.Evaluation results demonstrate that our model out-performs existing methods and successfully captures the semantic rules of both chemical languages.Chemical space and scaffold analysis show that the model can generate similar compounds with diverse scaffolds within the specified constraints.Additionally,to illustrate the model’s applicability in drug design,we conducted case studies in functional group editing,analogue design and linker design.
基金support from National Natural Science Foundation of China(NSFC,Grant numbers U22A20185,U21A20128,52175302 and 52305353)Aeronautical Science Foundation(ASFC-20230036077001)Fundamental Research Funds for the Central Universities(2022FRFK060009,HIT.DZI1.2023012).
文摘The excellent irradiation resistance,high strength and plasticity exhibited by high-entropy alloys(HEAs)make it candidate for engin-eering applications.Diffusion bonding of Al_(0.3)CoCrFeNi single-phase HEAs was carried out using electric-assisted diffusion bonding(EADB),and the effect of bonding temperature on the evolution of the interfacial microstructure and the mechanical properties was investigated.The results indicate that as the bonding temperature increases,the pores at the interface gradually decrease in size and undergo closure.The electric current significantly promotes the pore closure mechanism dominated by plastic deformation at the diffusion interface and promotes the recrystallisation behavior at the interface,and the fracture mode changes from intergranular fracture at the interface to jagged fracture along the grains spanning the weld parent material.Due to the activation effect of EADB,higher-strength diffusion bonding of high-entropy alloys can be achieved at the same temperature compared with the conventional hot-pressure diffusion bonding(HPDB)process.
基金Funded by the Natural Science Foundation of Jiangsu Province(No.BK20241529)China Postdoctoral Science Foundation(No.2024M750736)。
文摘This study aims to develop a chloride diffusion simulation method that considers the hydration microstructure and pore solution properties during the hydration of tricalcium silicate(C3S).The method combines the hydration simulation,thermodynamic calculation,and finite element analysis to examine the effects of pore solution,including effect of electrochemical potential,effect of chemical activity,and effect of mechanical interactions between ions,on the chloride effective diffusion coefficient of hydrated C3S paste.The results indicate that the effect of electrochemical potential on chloride diffusion becomes stronger with increasing hydration age due to the increase in the content of hydrated calcium silicate;as the hydration age increases,the effect of chemical activity on chloride diffusion weakens when the number of diffusible elements decreases;the effect of mechanical interactions between ions on chloride diffusion decreases with the increase of hydration age.
基金supported by the National Natural Science Foundation of China(Grant Nos.12365007 and 12265017)Yunnan Fundamental Research Projects(Grant Nos.202101AS070018 and 202101AV070015)+1 种基金the Scientific Research Foundation of the Yunnan Provincial Department of Education(Grant No.2023J1208)Xingdian Talents Support Program,and Yunnan Province Ten Thousand Talents Plan Young&Elite Talents Project,and Yunnan Province Computational Physics and Applied Science and Technology Innovation Team.The numerical simulation and significance estimation were performed on the Key Laboratory of High-Density Computing,Zhaotong University。
文摘Particle transport is a fundamental aspect of various systems,from artificial to biological.A common assumption is that particle motion follows Markovian(memoryless)processes in the absence of interaction between particles.However,hydrodynamic memory and the interaction between particles are ubiquitous,leaving many fundamental questions unanswered regarding transport of interacting particles involving hydrodynamic drag in corrugated channels,as described by the fractional Langevin equation.This study examines the hydrodynamic transport of interacting non-Brownian particles moving within a corrugated channel.We propose a method that relies on factors such as temperature,the driving force to alternate between no transport and finite net transport.Of importance is to note that the absence of transport results from the clogging,while the transport consists of collective motion and independent motion.The transport systems investigated in this work suggest the potential for sensor functionality within the system.Our findings may prove valuable for exploring the transport with hydrodynamic memory in various fields,including biology,physics,and chemistry.
文摘We study the two-dimensional(2D)Cauchy problem of nonhomogeneous Boussinesq system for magnetohydrodynamics convection without heat diffusion in the whole plane.Based on delicate weighted estimates,we derive the global existence and uniqueness of strong solutions.In particular,the initial data can be arbitrarily large and the initial density may contain vacuum states and even have compact support.
基金supported by the National Key Research and Development Program of China(2022YFB3505503)the National Natural Science Foundation of China(52201230)+2 种基金the Key R&D Program of Shandong Province(2022CXGC020307)the China Postdoctoral Science Foundation(2022M71204)the Beijing NOVA Program(Z211100002121092).
文摘The grain boundary diffusion process(GBDP)has proven to be an effective method for enhancing the coercivity of sintered Nd-Fe-B magnets.However,the limited diffusion depth and thicker shell struc-ture have impeded the further development of magnetic properties.Currently,the primary debates re-garding the mechanism of GBDP with Tb revolve around the dissolution-solidification mechanism and the atomic substitution mechanism.To clarify this mechanism,the microstructure evolution of sintered Nd-Fe-B magnets during the heating process of GBDP has been systematically studied by quenching at different tem peratures.In this study,it was found that the formation of TbFe_(2) phase is related to the dis-solution of _(2)Fe_(14)B grains during GBDP with Tb.The theory of mixing heat and phase separation further confirms that the Nd_(2)Fe_(14)B phase dissolves to form a mixed phase of Nd and TbFe_(2),which then solidifies into the(Nd,Tb)_(2)Fe_(14)B phase.Based on the discovery of the TbFe_(2) phase,the dissolution-solidification mechanism is considered the primary mechanism for GBDP.This is supported by the elemental content of the two typical core-shell structures observed.
文摘针对现有无数据模型窃取攻击技术在有限的查询预算下难以拟合原始训练集分布,进而影响对目标模型决策边界拟合效果问题,提出了一种基于Stable Diffusion的模型窃取攻击方法(Model Extraction Attack Based on Stable Diffusion,MEASD).利用预训练的Stable Diffusion生成训练数据可能涵盖多个域,并包含大量非判别性样本,设计了ILAF方法以优化Stable Diffusion生成的数据品质.将高质量合成数据的原始样本与由对抗样本生成器生成的对抗样本组成替代训练集.由DPA模块组合的替代模型基于替代训练集拟合目标模型的决策边界.实验结果表明,在四个主流的基准数据集上与EBFA和DMEAE方法相比,所提的MEASD方法能够将目标模型决策边界的拟合程度提高至84%,对目标模型的黑盒对抗攻击成功率超过68%,并且查询预算较低.MEASD方法能够有效地提升目标模型决策边界拟合效果及攻击成功率.
基金National Natural Science Foundation of China(52075449,5197052086)。
文摘The transient liquid-phase(TLP)diffusion bonding of GH5188 with a BNi-5 interlayer was focused on.Parameters were chosen and optimized for GH5188 alloy according to the TLP joining mechanism.The microstructure evolution and mechanical properties of the joints were studied.Results show that the relatively complete isothermal solidification zone(ISZ)ensures a reliable connection of the base metal(BM).Within the temperature range of 1110–1190°C,higher bonding temperatures can widen ISZ and promote joint composition homogenization,thus improving mechanical properties.However,the increase in precipitated phase has an adverse effect on the mechanical properties of the joint.The maximum shear strength,reaching 482 MPa,is achieved at 1130°C,representing 84.6%of BM strength.Within the pressure range of 5–15 MPa,both precipitated phases in adiabatic solidification zone(ASZ)and voids generated by partial melting increase.On the contrary,their sizes decrease significantly under higher bonding pressure,resulting in an upward trend in alloy mechanical properties.The maximum shear strength of 490 MPa is attained at a bonding pressure of 15 MPa.The joint exhibits a typical mixed fracture pattern,with the small brittle M_(23)C_(6) phase and voids significantly impacting mechanical properties.Nano-indentation tests indicate that ASZ is a potential source of cracks.
