Multi-way principal component analysis (MPCA) had been successfully applied to monitoring the batch and semi-batch process in most chemical industry. An improved MPCA approach, step-by-step adaptive MPCA (SAMPCA), usi...Multi-way principal component analysis (MPCA) had been successfully applied to monitoring the batch and semi-batch process in most chemical industry. An improved MPCA approach, step-by-step adaptive MPCA (SAMPCA), using the process variable trajectories to monitoring the batch process is presented in this paper. It does not need to estimate or fill in the unknown part of the process variable trajectory deviation from the current time until the end. The approach is based on a MPCA method that processes the data in a sequential and adaptive manner. The adaptive rate is easily controlled through a forgetting factor that controls the weight of past data in a summation. This algorithm is used to evaluate the industrial streptomycin fermentation process data and is compared with the traditional MPCA. The results show that the method is more advantageous than MPCA, especially when monitoring multi-stage batch process where the latent vector structure can change at several points during the batch.展开更多
A step-by-step load was utilized to mimic the load history of the backfill column in the in-situ curing process.The inner damage of the specimen during curing and uniaxial compressive testing was monitored by electric...A step-by-step load was utilized to mimic the load history of the backfill column in the in-situ curing process.The inner damage of the specimen during curing and uniaxial compressive testing was monitored by electrical resistivity and ultrasonic equipment.Results show that:1)Uniaxial compressive strength(UCS)and elastic modulus(EM)of the samples curing under pressure are higher than those of the control samples without pressure,ranging in ratio from 0.5%to 20.2%and 7.1%to 52.3%,respectively,and are influenced by the initial loading age(ILA)and stress strength ratio(SSR).The SSR during curing should not exceed 80%.2)The earlier the ILA is,the higher the total strain becomes.The higher the SSR applies,the larger the total strain gets.The creep strain increases with the increase of SSR and can be described by Burger’s viscoelastic creep model.When SSR is less than 80%,the earlier the ILA is,the smaller the creep strain becomes after the last step-loading.3)The stability of the early age backfill column under pressure can be monitored based on the change of ultrasonic pulse velocity(UPV)and electrical resistivity.展开更多
Metal-organic framework(MOF) thin films are multilayer materials ranging from nanometers to micrometers in thickness,physically or chemically adhesive to a(functionalized) substrate and,in an ideal case,exhibiting low...Metal-organic framework(MOF) thin films are multilayer materials ranging from nanometers to micrometers in thickness,physically or chemically adhesive to a(functionalized) substrate and,in an ideal case,exhibiting low roughness and high homogeneity.Various innovative approaches have been developed for MOF thin film fabrication.Among these advanced materials,surface-attached metal-organic frameworks(SURMOFs) are an important class of MOF films.SURMOFs,fabricated in a step-by-step liquid phase epitaxial(LPE) fashion by alternating deposition of metal and organic linker precursors on a functionalized substrate,for example,thiolate-based self-assembled monolayers(SAMs),have already exhibited their utility in both research and potential applications.SURMOFs combine surface science and the chemistry of MOFs,possessing the following unique advantages that cannot be accessed through other methods:(i) precisely controlling thickness,roughness and homogeneity as well as growth orientation,(ii) studying of MOF growth mechanism,(iii) modifying/tailoring MOFs' structures during the SURMOF growth and thus creating customizable properties,and(iv) existing in the form of thin film/membrane for direct applications,for example,as sensors.This review discusses the oriented and crystalline SURMOFs fabricated by LPE approach,covering their preparation,growth mechanism,and characterization methodology as well as applications based upon the most newly updated knowledge.展开更多
Due to easy re-stacking,low yield of few-layered MXenes(f-MXenes),the applications of MXenes are mainly restricted in multi-layered MXenes(m-MXenes)state.Although f-MXenes can be prepared from m-MXenes,after exfoliati...Due to easy re-stacking,low yield of few-layered MXenes(f-MXenes),the applications of MXenes are mainly restricted in multi-layered MXenes(m-MXenes)state.Although f-MXenes can be prepared from m-MXenes,after exfoliation process,a mass of sediments which are still essentially compact MXenes are usually directly discarded,leading to low utilization of raw m-MXenes.Herein,a classified preparation strategy is adopted to exploit the raw m-MXenes and traditional MXenes sediments,taking multi-layered Ti_(3)C_(2)T_(x)MXene as an example.Via rational delamination and subsequent treatment to Ti_(3)C_(2)T_(x)sediments,we succeed in achieving classified and large-scale preparation of various Ti_(3)C_(2)T_(x)MXene derivatives,including few-layered Ti_(3)C_(2)T_(x)(f-Ti_(3)C_(2)T_(x))powders,f-Ti_(3)C_(2)T_(x)films,and Ti_(3)C_(2)T_(x)MXene-derived nanowires with heterostructure of potassium titanate and Ti_(3)C_(2)T_(x).We demonstrate the necessity of“step-by-step delamination”towards traditional Ti_(3)C_(2)T_(x)sediments to improve the yield of f-Ti_(3)C_(2)T_(x)from 15%to 72%;the feasibility of“solution-phase flocculation(SPF)”to fundamentally solve the re-stacking phenomenon,and oxidation degradation issues of f-Ti_(3)C_(2)T_(x)during storage;as well as the convenience of SPF to deal with time-consuming issues of fabricating Ti_(3)C_(2)T_(x)films.What’s more,alkali-heat treatment of final Ti_(3)C_(2)T_(x)sediments turns waste into treasure of Ti_(3)C_(2)T_(x)-derived nanowires,leading to 100%utilization of raw Ti_(3)C_(2)T_(x).The content of one-dimensional(1D)nanowires in the hybrids can be adjusted by controlling alkalization time.The 3D architecture heterostructure composed of 1D nanowires and 2D nanosheets exhibits gorgeous application potential.This work can expand preparation and application of various MXenes derivatives,promoting process of various MXenes.展开更多
基金Supported by the National High-tech Program of China (No. 2001 AA413110).
文摘Multi-way principal component analysis (MPCA) had been successfully applied to monitoring the batch and semi-batch process in most chemical industry. An improved MPCA approach, step-by-step adaptive MPCA (SAMPCA), using the process variable trajectories to monitoring the batch process is presented in this paper. It does not need to estimate or fill in the unknown part of the process variable trajectory deviation from the current time until the end. The approach is based on a MPCA method that processes the data in a sequential and adaptive manner. The adaptive rate is easily controlled through a forgetting factor that controls the weight of past data in a summation. This algorithm is used to evaluate the industrial streptomycin fermentation process data and is compared with the traditional MPCA. The results show that the method is more advantageous than MPCA, especially when monitoring multi-stage batch process where the latent vector structure can change at several points during the batch.
基金Project(51974192)supported by the National Natural Science Foundation of ChinaProject(201803D31044)supported by the Program for Key Research Project of Shanxi Province in the Field of Social Development,ChinaProject(201801D121092)supported by the Applied Basic Research Project of Shanxi Province,China。
文摘A step-by-step load was utilized to mimic the load history of the backfill column in the in-situ curing process.The inner damage of the specimen during curing and uniaxial compressive testing was monitored by electrical resistivity and ultrasonic equipment.Results show that:1)Uniaxial compressive strength(UCS)and elastic modulus(EM)of the samples curing under pressure are higher than those of the control samples without pressure,ranging in ratio from 0.5%to 20.2%and 7.1%to 52.3%,respectively,and are influenced by the initial loading age(ILA)and stress strength ratio(SSR).The SSR during curing should not exceed 80%.2)The earlier the ILA is,the higher the total strain becomes.The higher the SSR applies,the larger the total strain gets.The creep strain increases with the increase of SSR and can be described by Burger’s viscoelastic creep model.When SSR is less than 80%,the earlier the ILA is,the smaller the creep strain becomes after the last step-loading.3)The stability of the early age backfill column under pressure can be monitored based on the change of ultrasonic pulse velocity(UPV)and electrical resistivity.
基金the European Union for funding the research projects on MOF thin films (Priority Program 1362 of the DFG)SUR-MOFs(6th FP, NMP4-CT-2006-032109)
文摘Metal-organic framework(MOF) thin films are multilayer materials ranging from nanometers to micrometers in thickness,physically or chemically adhesive to a(functionalized) substrate and,in an ideal case,exhibiting low roughness and high homogeneity.Various innovative approaches have been developed for MOF thin film fabrication.Among these advanced materials,surface-attached metal-organic frameworks(SURMOFs) are an important class of MOF films.SURMOFs,fabricated in a step-by-step liquid phase epitaxial(LPE) fashion by alternating deposition of metal and organic linker precursors on a functionalized substrate,for example,thiolate-based self-assembled monolayers(SAMs),have already exhibited their utility in both research and potential applications.SURMOFs combine surface science and the chemistry of MOFs,possessing the following unique advantages that cannot be accessed through other methods:(i) precisely controlling thickness,roughness and homogeneity as well as growth orientation,(ii) studying of MOF growth mechanism,(iii) modifying/tailoring MOFs' structures during the SURMOF growth and thus creating customizable properties,and(iv) existing in the form of thin film/membrane for direct applications,for example,as sensors.This review discusses the oriented and crystalline SURMOFs fabricated by LPE approach,covering their preparation,growth mechanism,and characterization methodology as well as applications based upon the most newly updated knowledge.
基金the National Natural ScienceFoundation of China(No.51901206)the fund from Taihu Electric Corporation 0001.
文摘Due to easy re-stacking,low yield of few-layered MXenes(f-MXenes),the applications of MXenes are mainly restricted in multi-layered MXenes(m-MXenes)state.Although f-MXenes can be prepared from m-MXenes,after exfoliation process,a mass of sediments which are still essentially compact MXenes are usually directly discarded,leading to low utilization of raw m-MXenes.Herein,a classified preparation strategy is adopted to exploit the raw m-MXenes and traditional MXenes sediments,taking multi-layered Ti_(3)C_(2)T_(x)MXene as an example.Via rational delamination and subsequent treatment to Ti_(3)C_(2)T_(x)sediments,we succeed in achieving classified and large-scale preparation of various Ti_(3)C_(2)T_(x)MXene derivatives,including few-layered Ti_(3)C_(2)T_(x)(f-Ti_(3)C_(2)T_(x))powders,f-Ti_(3)C_(2)T_(x)films,and Ti_(3)C_(2)T_(x)MXene-derived nanowires with heterostructure of potassium titanate and Ti_(3)C_(2)T_(x).We demonstrate the necessity of“step-by-step delamination”towards traditional Ti_(3)C_(2)T_(x)sediments to improve the yield of f-Ti_(3)C_(2)T_(x)from 15%to 72%;the feasibility of“solution-phase flocculation(SPF)”to fundamentally solve the re-stacking phenomenon,and oxidation degradation issues of f-Ti_(3)C_(2)T_(x)during storage;as well as the convenience of SPF to deal with time-consuming issues of fabricating Ti_(3)C_(2)T_(x)films.What’s more,alkali-heat treatment of final Ti_(3)C_(2)T_(x)sediments turns waste into treasure of Ti_(3)C_(2)T_(x)-derived nanowires,leading to 100%utilization of raw Ti_(3)C_(2)T_(x).The content of one-dimensional(1D)nanowires in the hybrids can be adjusted by controlling alkalization time.The 3D architecture heterostructure composed of 1D nanowires and 2D nanosheets exhibits gorgeous application potential.This work can expand preparation and application of various MXenes derivatives,promoting process of various MXenes.
