To resolve the control adaptability problem of TV media in complex competitive environment, a control system model of TV media organization structure was designed. Based on the designed system model for TV media organ...To resolve the control adaptability problem of TV media in complex competitive environment, a control system model of TV media organization structure was designed. Based on the designed system model for TV media organization structure, the relations among the main factors of the system constitution, missions, organizing decision entity, and carrying bodies were analyzed. By means of applying multi-objective decision method and complex control system theory, and combining the integration model of TV media organization structure, the basic model was concluded and the corresponding parameters were designed. The current organization process of TV media is analyzed by this model, which comes to the adaptability appearance with different parameters. The results indicate that the model can estimate current TV media organization structure for the chain appearance of communications and the correlation between platforms and policy-making agencies.展开更多
Optically active form of α-cyano-3-phenoxybenzyl (CPB) alcohol, building block of pyrethroid insecticides, was synthesized as its acetate by the combination of anion-exchange resin (D301)-catalyzed transcyanation bet...Optically active form of α-cyano-3-phenoxybenzyl (CPB) alcohol, building block of pyrethroid insecticides, was synthesized as its acetate by the combination of anion-exchange resin (D301)-catalyzed transcyanation between m-phenoxybenzaldehyde (m-PBA) and acetone cyanohydrin (AC), and lipase (from Alcaligenes sp.)-catalyzed enantioselective transesterification of the resulting cyanohydrin with vinyl acetate. Through optimizing technological conditions, the catalyzing efficiency was improved considerably compared to methods previously reported. Concentrations of CPB acetate were determined by gas chromatograph. The enantio excess (e.e.) values of CPB acetate were measured by NMR (nuclear magnetic resonance) method. Effects of solvents and temperatures on this reaction were studied. Cyclohexane was shown to be the best solvent among the three tested solvents. 55 °C was the optimal temperature for higher degree of conversion. External diffusion limitation was excluded by raising the rotational speed to 220 r/min. However, internal diffusion could not be ignored, since the catalyst (lipase) was an immobilized enzyme and its particle dimension was not made small enough. The reaction rate was substantially accelerated when the reactant (m-PBA) concentration was as high as 249 mmol/L, but decreased when the initial concentration of m-PBA reached to 277 mmol/L. It was also found that the catalyzing capability of recovered lipase was high enough to use several batches. Study of the mole ratio of AC to m-PBA showed that 2:1 was the best choice. The strategy of adding base catalyst D301 was found to be an important factor in improving the degree of conversion of the reaction from 20% to 80%. The highest degree of conversion of the reaction has reached up to 80%.展开更多
The motion of organization center of three_dimensional untwisted scroll waves in excitable media with single diffusion is studied by singular perturbation method in this paper. The relation of curvature and the linear...The motion of organization center of three_dimensional untwisted scroll waves in excitable media with single diffusion is studied by singular perturbation method in this paper. The relation of curvature and the linear law are derived for untwisted organization center. These results have explicit physical meaning and are in good agreement with experiments.展开更多
With help of establishing the moving coordinate on the wave front surface and the perturbation analysis in the boundary layer,the structures of wave front and organization center in excitable media were studied. The e...With help of establishing the moving coordinate on the wave front surface and the perturbation analysis in the boundary layer,the structures of wave front and organization center in excitable media were studied. The eikonal equation of wave front surface and general equation of organization center were obtained. These eikonal equations reveal the wave front surfaces have structures of twisted scroll wave and Mbius band, the organization centers have structures of knotted and linked ring. These theoretical results not only explain the wave patterns of BZ(Belousov-Zhabotinskii) chemical reaction but also give several possibility structures of wave front surface and organization center in general excitable media.展开更多
A novel spectrofluorimetric method for the determination of L ascorbic acid is proposed. It is based on the inhibition of L ascorbic acid on the formation of 2,3 diaminophenazine, which is an oxidation product of ...A novel spectrofluorimetric method for the determination of L ascorbic acid is proposed. It is based on the inhibition of L ascorbic acid on the formation of 2,3 diaminophenazine, which is an oxidation product of o phenylenediamine catalyzed by laccase .The fluorescence (at λ ex /λ em =464 nm /530 nnm) was enhanced strongly in the presence of organic media . The mechanism of o phenylenediamine oxidation reaction catalyzed by laccase in the presence of L ascorbic acid is discussed .L ascorbic acid is determined in the ethanol, 1,4 dioxane and acetone over the linear range of 4.0×10 -7 ~1.2×10 -4 mol/L, 4.0×10 -7 ~ 8.0×10 -5 mol/L and 4.0×10 -7 ~1.0×10 -4 mol/L with a detection limit of 1.20×10 -8 mol/L,1.19×10 -8 mol/L and 1.24×10 -8 mol/L, respectively. The method has been successfully applied to the simple and rapid determination of L ascorbic acid in pharmaceuticals and milk powder.展开更多
Covalent organic frameworks(COFs), as an emerging class of porous crystalline materials constructed by covalent links between the building monomers, have gained tremendous attention. Over the past 15 years, COFs have ...Covalent organic frameworks(COFs), as an emerging class of porous crystalline materials constructed by covalent links between the building monomers, have gained tremendous attention. Over the past 15 years, COFs have made rapid progress and substantial development in the chemistry and materials fields. However, the synthesis of COFs has been dominated by solvothermal methods for a long time and it usually involves high temperature, high pressure and toxic organic solvents, which created many challenges for environmental considerations. Recently,the exploration of new approaches for facile fabrication of COFs has aroused extensive interest. Hence, in this review, we comprehensively describe the synthetic strategies of COFs from the aspects of nonconventional heating methods and reaction media. In addition, the advantages,limitations and properties of the preparation methods are compared. Finally, we outline the main challenges and development prospects of the synthesis of COFs in the future and propose some possible solutions.展开更多
A well-organized system of internal communication is vital in any organization open to improvement and change, pursuing better management of its resources and caring forgood work atmosphere. Internal communication is ...A well-organized system of internal communication is vital in any organization open to improvement and change, pursuing better management of its resources and caring forgood work atmosphere. Internal communication is primarily to provide efficient, mutual flow of information between employees and management staff at all levels in each area of the organization. In order to present internal communication tools and evaluate their effectiveness a survey study was conducted among the employees of the listed media company Cyfrowy Polsat, one of the two leading private TV groups in Poland. The study involved 136 employees (17% of total employment). The majority of respondents were male (85%). All the respondents were 23 to 47 years of age. Almost half were below 24 years of age and 38% represented the age group 25-34 years of age. The majority of respondents declared higher education with master degree and working time exceeding three years. The survey showed that the dominant form of communication is message distribution via electronic channels which confirmed the research assumption that there was a dehumanization of contacts and indirect communication dominated over direct contact. Limited direct contact was also recognized as the major cause of conflicts and disputes. The study was based on the analysis of literature and source materials (reports, statistics, newsletters, and legal acts). Additionally, the paper provides the presentation of Cyfrowy Polsat's position in the Polish media market as well as the strategies and objectives of the company.展开更多
A pot research has been conducted in Horticultural Department Nursery, Faculty of Agricultural and Forestry, Duhok University, during the period of May 15, 2012-Sep. 1, 2012. The study involved in testing the effects ...A pot research has been conducted in Horticultural Department Nursery, Faculty of Agricultural and Forestry, Duhok University, during the period of May 15, 2012-Sep. 1, 2012. The study involved in testing the effects of two amended organic media (loam + sheep manure and loam + peat moss (1:1)) and different concentrations of seaweed (sea force 2) extract including (0, 0.5, 1, 1.5 and 2 mL/L) on growth and flowering of Periwinkle (Vinca rosea) plant. The results showed that growing vinca plants in peat moss medium and spraying sea force 2 extract with low concentrations especially 0.5 mL/L resulted in positive significant difference in vegetative and flowering characteristics.展开更多
We theoretically analyze the organizing filament of small amplitude scroll waves in general excitable media by perturbation method and explicitly give the expressions of coefficients in Keener theory. In particular fo...We theoretically analyze the organizing filament of small amplitude scroll waves in general excitable media by perturbation method and explicitly give the expressions of coefficients in Keener theory. In particular for the excitable media with equal diffusion, we obtain a close system for the motion of the filament. With an example of the Oregonator model, our results are in good agreement with those simulated by Winfree.展开更多
Purpose:This study aims to construct an ontology to model the semantics of social media streams,in particular,trending topics and public issues.Design/methodology/approach:Our knowledge base included 10 public events ...Purpose:This study aims to construct an ontology to model the semantics of social media streams,in particular,trending topics and public issues.Design/methodology/approach:Our knowledge base included 10 public events and topics from Weibo respectively,which were collected through keyword search and a crawler program.We used a semi-automatic approach to model and annotate the semantics in social media,and adapted the multi-layered ontology to refine the design based on previous researches,then we used named entity recognition(NER) to extract entities to instantiate the ontology.Relationships were extracted based on co-occurrence measures.Finally,we manually conducted post-filtering evaluation and edited the extracted entities and relationships.Findings:An initial assessment demonstrated that our multi-layered ontology supports various types of queries and analyses in the public issue knowledge base(PIKB),which can serve as an effective tool to query,understand and trace public issues.Research limitations:Manual involvement cannot meet the requirements for challenges of sustainable developments.Since the relationships extracted are fully based on the co-occurrence of entities,rich semantic relationships,such as how much the key players have been involved,could not be fully reflected.Besides,the user evaluation is necessary for further ontology assessment.Practical implications:The PIKB can be used by regular Web users and policy makers to query,understand,and make sense of public events and topics.The methodology and reusable ontology model are useful for institutions that are interested in making use of the social media data.Originality/value:In this study,a multi-layered ontology is applied to model the evolving semantics of public events and trending topics in social media,and the semi-automatic approach could make it possible to extract entities and relationships from large amount of unstructured short texts of user generated content(UGC) from social media.展开更多
This study aims to investigate methyl tert-butyl ether(MTBE) dissolution in saturated porous media.A series of1 D column experiments were conducted in laboratory to obtain MTBE dissolution data with different groundwa...This study aims to investigate methyl tert-butyl ether(MTBE) dissolution in saturated porous media.A series of1 D column experiments were conducted in laboratory to obtain MTBE dissolution data with different groundwater velocity,initial MTBE saturation and grain size of porous medium,and in the presence of other nonaqueous liquids.Results indicate that higher groundwater velocity increases MTBE dissolution rate and higher initial MTBE saturation reduces effective permeability to slow MTBE dissolution rate.Smaller grain size medium gives higher MTBE dissolution rate because of higher permeability.The addition of trichloroethylene enhances MTBE dissolution,with an optimal mass ratio of 10:2,while the presence of p-xylene prolongs complete dissolution of MTBE.Mass transfer correlations are developed for MTBE dissolution rate based on the degree of MTBE saturation Sn.Mass transfer rate is characterized by Re' with a high exponent for 0.3000<Sn<0.5482,while it is related to medium grain size and Sn for Sn≤0.3000.展开更多
Decomposition of acetone cyanohydrin is the first-step reaction for preparing (S)-α-cyano-3-phenoxybenzyl alcohol (CPBA) by the one-pot method in organic media. Considering the compatibility of biocatalysts with...Decomposition of acetone cyanohydrin is the first-step reaction for preparing (S)-α-cyano-3-phenoxybenzyl alcohol (CPBA) by the one-pot method in organic media. Considering the compatibility of biocatalysts with chemical catalysts and the successive operation in the bioreactor, anion exchange resin (D301) was used as catalyst for this reaction. External diffusion limitation was excluded by raising rotational speed to higher than 190r·min^-1 in both solvents. Internal diffusion limitation was verified to be insignificant in this reaction system. The effect of acetone cyanohydrin concentration on the reaction was also investigated. An intrinsic kinetic model was proposed when the mass transfer limitation was excluded, and the average deviation of the model is 10.5%.展开更多
An attempt was made to improve the adsorption capability of the normal sand to be used as adsorbent for phenol and cadmium This has been done by producing a coated sand media. The coating process was done using emulsi...An attempt was made to improve the adsorption capability of the normal sand to be used as adsorbent for phenol and cadmium This has been done by producing a coated sand media. The coating process was done using emulsion asphalt to convert the normal sand to carbonated sand by using chemical treatment with sulfuric acid. The production process involves mixing of the sand with asphalt and an acid, then subjecting the mix to a heating process. Different mixing ratios, heating temperatures and times (activation times) were tried to obtain the optimum conditions at which the highest removal efficiency is obtained. Three types of acids were tried acetic acid, phosphoric acid and sulfuric acid. It was found that the sulfuric acid requires the lowest activation time, hence selected for the production. The removal efficiency of the produced media was significantly affected by the temperature, mixing ratio and activation heating time. The results show that, the optimum conditions for the production process are 350 , (1:2:3) (Asphalt/acid/sand) and 52 min for temperature, mixing ratio and activation heating time respectively. The final product was tested and found effective as an adsorbent media for phenol and cadmium. The removal efficiencies of these two pollutants in a batch adsorber were found 82.42% and 86.67%, respectively. The X-R diffraction and FTIR spectra tests had proved this media as an adsorbent.展开更多
文摘To resolve the control adaptability problem of TV media in complex competitive environment, a control system model of TV media organization structure was designed. Based on the designed system model for TV media organization structure, the relations among the main factors of the system constitution, missions, organizing decision entity, and carrying bodies were analyzed. By means of applying multi-objective decision method and complex control system theory, and combining the integration model of TV media organization structure, the basic model was concluded and the corresponding parameters were designed. The current organization process of TV media is analyzed by this model, which comes to the adaptability appearance with different parameters. The results indicate that the model can estimate current TV media organization structure for the chain appearance of communications and the correlation between platforms and policy-making agencies.
基金Project supported by the National Natural Science Foundation of China (No. 20336010) and the National Basic Research Program (973)of China (No. 2003CB716008)
文摘Optically active form of α-cyano-3-phenoxybenzyl (CPB) alcohol, building block of pyrethroid insecticides, was synthesized as its acetate by the combination of anion-exchange resin (D301)-catalyzed transcyanation between m-phenoxybenzaldehyde (m-PBA) and acetone cyanohydrin (AC), and lipase (from Alcaligenes sp.)-catalyzed enantioselective transesterification of the resulting cyanohydrin with vinyl acetate. Through optimizing technological conditions, the catalyzing efficiency was improved considerably compared to methods previously reported. Concentrations of CPB acetate were determined by gas chromatograph. The enantio excess (e.e.) values of CPB acetate were measured by NMR (nuclear magnetic resonance) method. Effects of solvents and temperatures on this reaction were studied. Cyclohexane was shown to be the best solvent among the three tested solvents. 55 °C was the optimal temperature for higher degree of conversion. External diffusion limitation was excluded by raising the rotational speed to 220 r/min. However, internal diffusion could not be ignored, since the catalyst (lipase) was an immobilized enzyme and its particle dimension was not made small enough. The reaction rate was substantially accelerated when the reactant (m-PBA) concentration was as high as 249 mmol/L, but decreased when the initial concentration of m-PBA reached to 277 mmol/L. It was also found that the catalyzing capability of recovered lipase was high enough to use several batches. Study of the mole ratio of AC to m-PBA showed that 2:1 was the best choice. The strategy of adding base catalyst D301 was found to be an important factor in improving the degree of conversion of the reaction from 20% to 80%. The highest degree of conversion of the reaction has reached up to 80%.
文摘The motion of organization center of three_dimensional untwisted scroll waves in excitable media with single diffusion is studied by singular perturbation method in this paper. The relation of curvature and the linear law are derived for untwisted organization center. These results have explicit physical meaning and are in good agreement with experiments.
文摘With help of establishing the moving coordinate on the wave front surface and the perturbation analysis in the boundary layer,the structures of wave front and organization center in excitable media were studied. The eikonal equation of wave front surface and general equation of organization center were obtained. These eikonal equations reveal the wave front surfaces have structures of twisted scroll wave and Mbius band, the organization centers have structures of knotted and linked ring. These theoretical results not only explain the wave patterns of BZ(Belousov-Zhabotinskii) chemical reaction but also give several possibility structures of wave front surface and organization center in general excitable media.
文摘A novel spectrofluorimetric method for the determination of L ascorbic acid is proposed. It is based on the inhibition of L ascorbic acid on the formation of 2,3 diaminophenazine, which is an oxidation product of o phenylenediamine catalyzed by laccase .The fluorescence (at λ ex /λ em =464 nm /530 nnm) was enhanced strongly in the presence of organic media . The mechanism of o phenylenediamine oxidation reaction catalyzed by laccase in the presence of L ascorbic acid is discussed .L ascorbic acid is determined in the ethanol, 1,4 dioxane and acetone over the linear range of 4.0×10 -7 ~1.2×10 -4 mol/L, 4.0×10 -7 ~ 8.0×10 -5 mol/L and 4.0×10 -7 ~1.0×10 -4 mol/L with a detection limit of 1.20×10 -8 mol/L,1.19×10 -8 mol/L and 1.24×10 -8 mol/L, respectively. The method has been successfully applied to the simple and rapid determination of L ascorbic acid in pharmaceuticals and milk powder.
基金supported by the National Natural Science Foundation of China (Nos. 21822407 and 22074154)Youth Innovation Promotion Association CAS (2021420)the Foundation for Sci & Tech Research Project of Gansu Province (20JR10RA045 and 20JR5RA573)。
文摘Covalent organic frameworks(COFs), as an emerging class of porous crystalline materials constructed by covalent links between the building monomers, have gained tremendous attention. Over the past 15 years, COFs have made rapid progress and substantial development in the chemistry and materials fields. However, the synthesis of COFs has been dominated by solvothermal methods for a long time and it usually involves high temperature, high pressure and toxic organic solvents, which created many challenges for environmental considerations. Recently,the exploration of new approaches for facile fabrication of COFs has aroused extensive interest. Hence, in this review, we comprehensively describe the synthetic strategies of COFs from the aspects of nonconventional heating methods and reaction media. In addition, the advantages,limitations and properties of the preparation methods are compared. Finally, we outline the main challenges and development prospects of the synthesis of COFs in the future and propose some possible solutions.
文摘A well-organized system of internal communication is vital in any organization open to improvement and change, pursuing better management of its resources and caring forgood work atmosphere. Internal communication is primarily to provide efficient, mutual flow of information between employees and management staff at all levels in each area of the organization. In order to present internal communication tools and evaluate their effectiveness a survey study was conducted among the employees of the listed media company Cyfrowy Polsat, one of the two leading private TV groups in Poland. The study involved 136 employees (17% of total employment). The majority of respondents were male (85%). All the respondents were 23 to 47 years of age. Almost half were below 24 years of age and 38% represented the age group 25-34 years of age. The majority of respondents declared higher education with master degree and working time exceeding three years. The survey showed that the dominant form of communication is message distribution via electronic channels which confirmed the research assumption that there was a dehumanization of contacts and indirect communication dominated over direct contact. Limited direct contact was also recognized as the major cause of conflicts and disputes. The study was based on the analysis of literature and source materials (reports, statistics, newsletters, and legal acts). Additionally, the paper provides the presentation of Cyfrowy Polsat's position in the Polish media market as well as the strategies and objectives of the company.
文摘A pot research has been conducted in Horticultural Department Nursery, Faculty of Agricultural and Forestry, Duhok University, during the period of May 15, 2012-Sep. 1, 2012. The study involved in testing the effects of two amended organic media (loam + sheep manure and loam + peat moss (1:1)) and different concentrations of seaweed (sea force 2) extract including (0, 0.5, 1, 1.5 and 2 mL/L) on growth and flowering of Periwinkle (Vinca rosea) plant. The results showed that growing vinca plants in peat moss medium and spraying sea force 2 extract with low concentrations especially 0.5 mL/L resulted in positive significant difference in vegetative and flowering characteristics.
文摘We theoretically analyze the organizing filament of small amplitude scroll waves in general excitable media by perturbation method and explicitly give the expressions of coefficients in Keener theory. In particular for the excitable media with equal diffusion, we obtain a close system for the motion of the filament. With an example of the Oregonator model, our results are in good agreement with those simulated by Winfree.
基金supported by Beijing Thinker Workshop(Grant No.XK201211001)
文摘Purpose:This study aims to construct an ontology to model the semantics of social media streams,in particular,trending topics and public issues.Design/methodology/approach:Our knowledge base included 10 public events and topics from Weibo respectively,which were collected through keyword search and a crawler program.We used a semi-automatic approach to model and annotate the semantics in social media,and adapted the multi-layered ontology to refine the design based on previous researches,then we used named entity recognition(NER) to extract entities to instantiate the ontology.Relationships were extracted based on co-occurrence measures.Finally,we manually conducted post-filtering evaluation and edited the extracted entities and relationships.Findings:An initial assessment demonstrated that our multi-layered ontology supports various types of queries and analyses in the public issue knowledge base(PIKB),which can serve as an effective tool to query,understand and trace public issues.Research limitations:Manual involvement cannot meet the requirements for challenges of sustainable developments.Since the relationships extracted are fully based on the co-occurrence of entities,rich semantic relationships,such as how much the key players have been involved,could not be fully reflected.Besides,the user evaluation is necessary for further ontology assessment.Practical implications:The PIKB can be used by regular Web users and policy makers to query,understand,and make sense of public events and topics.The methodology and reusable ontology model are useful for institutions that are interested in making use of the social media data.Originality/value:In this study,a multi-layered ontology is applied to model the evolving semantics of public events and trending topics in social media,and the semi-automatic approach could make it possible to extract entities and relationships from large amount of unstructured short texts of user generated content(UGC) from social media.
基金Supported by the National Natural Science Foundation of China(41201497)
文摘This study aims to investigate methyl tert-butyl ether(MTBE) dissolution in saturated porous media.A series of1 D column experiments were conducted in laboratory to obtain MTBE dissolution data with different groundwater velocity,initial MTBE saturation and grain size of porous medium,and in the presence of other nonaqueous liquids.Results indicate that higher groundwater velocity increases MTBE dissolution rate and higher initial MTBE saturation reduces effective permeability to slow MTBE dissolution rate.Smaller grain size medium gives higher MTBE dissolution rate because of higher permeability.The addition of trichloroethylene enhances MTBE dissolution,with an optimal mass ratio of 10:2,while the presence of p-xylene prolongs complete dissolution of MTBE.Mass transfer correlations are developed for MTBE dissolution rate based on the degree of MTBE saturation Sn.Mass transfer rate is characterized by Re' with a high exponent for 0.3000<Sn<0.5482,while it is related to medium grain size and Sn for Sn≤0.3000.
基金Supported by the National Natural Science Foundation of China(No.29876037)and the Natural Science Foundation ofZhejiang Province(No.296068)
文摘Decomposition of acetone cyanohydrin is the first-step reaction for preparing (S)-α-cyano-3-phenoxybenzyl alcohol (CPBA) by the one-pot method in organic media. Considering the compatibility of biocatalysts with chemical catalysts and the successive operation in the bioreactor, anion exchange resin (D301) was used as catalyst for this reaction. External diffusion limitation was excluded by raising rotational speed to higher than 190r·min^-1 in both solvents. Internal diffusion limitation was verified to be insignificant in this reaction system. The effect of acetone cyanohydrin concentration on the reaction was also investigated. An intrinsic kinetic model was proposed when the mass transfer limitation was excluded, and the average deviation of the model is 10.5%.
文摘An attempt was made to improve the adsorption capability of the normal sand to be used as adsorbent for phenol and cadmium This has been done by producing a coated sand media. The coating process was done using emulsion asphalt to convert the normal sand to carbonated sand by using chemical treatment with sulfuric acid. The production process involves mixing of the sand with asphalt and an acid, then subjecting the mix to a heating process. Different mixing ratios, heating temperatures and times (activation times) were tried to obtain the optimum conditions at which the highest removal efficiency is obtained. Three types of acids were tried acetic acid, phosphoric acid and sulfuric acid. It was found that the sulfuric acid requires the lowest activation time, hence selected for the production. The removal efficiency of the produced media was significantly affected by the temperature, mixing ratio and activation heating time. The results show that, the optimum conditions for the production process are 350 , (1:2:3) (Asphalt/acid/sand) and 52 min for temperature, mixing ratio and activation heating time respectively. The final product was tested and found effective as an adsorbent media for phenol and cadmium. The removal efficiencies of these two pollutants in a batch adsorber were found 82.42% and 86.67%, respectively. The X-R diffraction and FTIR spectra tests had proved this media as an adsorbent.