Eco-friendly and biodegradable novel hydrogel were prepared by blending and solution casting method. The designed hydrogel is based on chitosan/ PEG600/Gurgam with carbon nanofiller along silane crosslinked (TEOS) wit...Eco-friendly and biodegradable novel hydrogel were prepared by blending and solution casting method. The designed hydrogel is based on chitosan/ PEG600/Gurgam with carbon nanofiller along silane crosslinked (TEOS) with pH sensitive response to controlled release of drug in biomedical materials and agriculture industry. The various concentration of carbon nanofiller is used to analyze its effect on the fabricated hydrogel characteristics by using FTIR, SEM, TGA, swelling studies (water, buffer and ionic solution). Spectra of FTIR reflected both established and newly developed groups (like hydrogel). COOH group presence is clearly observed in this range in the carbon filler reinforced hydrogel. The SEM micrographs show that CPG0.003 had a collection of polysaccharide chains as thin helices, which is attributed to the increase in the size of porosity. TGA shows to increase concentration of nanofiller enhanced the thermal stability of the designed hydrogels at temperature 25˚C to 550˚C mass loss percentage decrease upto 20% and increase thermal stability. This pH response made these resultant hydrogels as fruitful competitor against the many reported controlled release application.展开更多
A feasible method for synthesizing millimeter-wave conical array and optimizing low cross-polarization is proposed.Starting from the far-field superposition principle,an efficient approach including element mutual cou...A feasible method for synthesizing millimeter-wave conical array and optimizing low cross-polarization is proposed.Starting from the far-field superposition principle,an efficient approach including element mutual coupling and mounted platform effects is used to calculate the far-field patterns.A coordinate transform is applied to create polarization quantities,and a general process for the element polarized pattern transformation is performed.Corresponding numerical example is given and the desired sidelobe level and low cross-polarization are optimized.The numerical results indicate the proposed method is valid.展开更多
Six N-alkyl-4＇-methyl-1,1＇-biphenyl-2-sulfonamides were synthesized facilely and efficiently from low cost and readily available benzenesulfonyl chloride and C1-C4 fatty amines via linking DoM reaction with Suzuki r...Six N-alkyl-4＇-methyl-1,1＇-biphenyl-2-sulfonamides were synthesized facilely and efficiently from low cost and readily available benzenesulfonyl chloride and C1-C4 fatty amines via linking DoM reaction with Suzuki reaction.The structures of the new compounds synthesized were confirmed by elemental analysis,IR,1H NMR and MS.This new method makes a feature of low cost and readily available starting material,fewer steps,mild condition,easiness to operate and higher yield.展开更多
The reduction of TE-scattering by a conducting cylinder with multiple surface impedance loads is investigated. Synthesis procedures are developed to find the optimal loading which result in zero scattering in the desi...The reduction of TE-scattering by a conducting cylinder with multiple surface impedance loads is investigated. Synthesis procedures are developed to find the optimal loading which result in zero scattering in the desired directions or at several frequencies. Numerical results of these procedures are presented. The theoretical predictions are confirmed with an experiment. The proposed synthesis procedure is completely general and can be applied to arbitrarily shaped conducting bodies.展开更多
Based on the different reactivity of stannyl and bromo groups, (Z)-α-bromovinylstannanes can undergo the cross-coupling reaction with alkynyl Grignard reagents in the presence of tetrakis(triphenylphosphine)palladium...Based on the different reactivity of stannyl and bromo groups, (Z)-α-bromovinylstannanes can undergo the cross-coupling reaction with alkynyl Grignard reagents in the presence of tetrakis(triphenylphosphine)palladium(0) catalyst in THF at room temperature to afford stereoselectively 1,3-enynylstannanes in good yields.展开更多
Cross-depiction is the recognition—and synthesis—of objects whether they are photographed,painted, drawn, etc. It is a significant yet underresearched problem. Emulating the remarkable human ability to recognise and...Cross-depiction is the recognition—and synthesis—of objects whether they are photographed,painted, drawn, etc. It is a significant yet underresearched problem. Emulating the remarkable human ability to recognise and depict objects in an astonishingly wide variety of depictive forms is likely to advance both the foundations and the applications of computer vision. In this paper we motivate the cross-depiction problem, explain why it is difficult, and discuss some current approaches. Our main conclusions are(i) appearance-based recognition systems tend to be over-fitted to one depiction,(ii) models that explicitly encode spatial relations between parts are more robust,and(iii) recognition and non-photorealistic synthesis are related tasks.展开更多
Polyaddition using isocyanate and polyol forms polyurethane elastomer (PUE). However, this method has rarely been applied to the construction of PUEs containing sucrose. Hence, the introduction of sucrose (disaccharid...Polyaddition using isocyanate and polyol forms polyurethane elastomer (PUE). However, this method has rarely been applied to the construction of PUEs containing sucrose. Hence, the introduction of sucrose (disaccharide) as a cross-linker via polyaddition remains a challenging subject in polymer chemistry. Here, we report the synthesis of PUEs using an aromatic isocyanate (4,4’-diphenylmethane diisocyanate), polyols including a polyether polyol (polytetramethylene glycol) and two polyester polyols (polycaprolactone and polycarbonate diols), and sucrose as a crosslinker by a one-shot method. The PUEs containing sucrose were successfully produced. The use of sucrose was essential to obtain the desired PUEs containing sucrose units in the main chain.展开更多
A novel lactic acid-based cross-linked poly（ester-amide） （LCPEA） was synthesized. The gel fraction of the LCPEA could be modulated by the reaction conditions and it affected the mechanical and thermal properties o...A novel lactic acid-based cross-linked poly（ester-amide） （LCPEA） was synthesized. The gel fraction of the LCPEA could be modulated by the reaction conditions and it affected the mechanical and thermal properties of the LCPEA. The tensile strength, elastic modulus and bend strength of the LCPEA of 65% gel fraction were 4.65, 136.55 and 39.63 MPa, respectively. The thermal decomposition temperature （50 wt%） of the LCPEA was around 410℃.展开更多
A pentamodule assembly approach has been established for total synthesis of the naturally occurring(-)-palmyrolide A and(+)-5,7-epi-palmyrolide A.By using the racemic tert-butyl carbinol-containing alkyl iodide,the tw...A pentamodule assembly approach has been established for total synthesis of the naturally occurring(-)-palmyrolide A and(+)-5,7-epi-palmyrolide A.By using the racemic tert-butyl carbinol-containing alkyl iodide,the two diastereoisomeric macrolides could be obtained from the same sequence of reactions,demonstrating the flexibility of the multimodule assembly strategy for diverted total synthesis.展开更多
Based on the different reactivity of selanyl and bromo groups,( E)-α- bromovinylselenides can undergo sequential cross coupling reactions with nucleophiles in the presence of transition metal complexes to form two ca...Based on the different reactivity of selanyl and bromo groups,( E)-α- bromovinylselenides can undergo sequential cross coupling reactions with nucleophiles in the presence of transition metal complexes to form two carbon-carbon bonds in the same olefinic carbon leading to trisubstituted alkenes stereoselectively in good yields.展开更多
文摘Eco-friendly and biodegradable novel hydrogel were prepared by blending and solution casting method. The designed hydrogel is based on chitosan/ PEG600/Gurgam with carbon nanofiller along silane crosslinked (TEOS) with pH sensitive response to controlled release of drug in biomedical materials and agriculture industry. The various concentration of carbon nanofiller is used to analyze its effect on the fabricated hydrogel characteristics by using FTIR, SEM, TGA, swelling studies (water, buffer and ionic solution). Spectra of FTIR reflected both established and newly developed groups (like hydrogel). COOH group presence is clearly observed in this range in the carbon filler reinforced hydrogel. The SEM micrographs show that CPG0.003 had a collection of polysaccharide chains as thin helices, which is attributed to the increase in the size of porosity. TGA shows to increase concentration of nanofiller enhanced the thermal stability of the designed hydrogels at temperature 25˚C to 550˚C mass loss percentage decrease upto 20% and increase thermal stability. This pH response made these resultant hydrogels as fruitful competitor against the many reported controlled release application.
基金supported by the Emphases Foundation of Southwest China Institute of Electronic Technology under Grant No. H090024
文摘A feasible method for synthesizing millimeter-wave conical array and optimizing low cross-polarization is proposed.Starting from the far-field superposition principle,an efficient approach including element mutual coupling and mounted platform effects is used to calculate the far-field patterns.A coordinate transform is applied to create polarization quantities,and a general process for the element polarized pattern transformation is performed.Corresponding numerical example is given and the desired sidelobe level and low cross-polarization are optimized.The numerical results indicate the proposed method is valid.
文摘Six N-alkyl-4＇-methyl-1,1＇-biphenyl-2-sulfonamides were synthesized facilely and efficiently from low cost and readily available benzenesulfonyl chloride and C1-C4 fatty amines via linking DoM reaction with Suzuki reaction.The structures of the new compounds synthesized were confirmed by elemental analysis,IR,1H NMR and MS.This new method makes a feature of low cost and readily available starting material,fewer steps,mild condition,easiness to operate and higher yield.
文摘The reduction of TE-scattering by a conducting cylinder with multiple surface impedance loads is investigated. Synthesis procedures are developed to find the optimal loading which result in zero scattering in the desired directions or at several frequencies. Numerical results of these procedures are presented. The theoretical predictions are confirmed with an experiment. The proposed synthesis procedure is completely general and can be applied to arbitrarily shaped conducting bodies.
基金Project supported by the National Natural Science Foundation of China (No. 20062002) and the Natural Science Foundation of Jiangxi Province (No. 20040307).
文摘Based on the different reactivity of stannyl and bromo groups, (Z)-α-bromovinylstannanes can undergo the cross-coupling reaction with alkynyl Grignard reagents in the presence of tetrakis(triphenylphosphine)palladium(0) catalyst in THF at room temperature to afford stereoselectively 1,3-enynylstannanes in good yields.
文摘Cross-depiction is the recognition—and synthesis—of objects whether they are photographed,painted, drawn, etc. It is a significant yet underresearched problem. Emulating the remarkable human ability to recognise and depict objects in an astonishingly wide variety of depictive forms is likely to advance both the foundations and the applications of computer vision. In this paper we motivate the cross-depiction problem, explain why it is difficult, and discuss some current approaches. Our main conclusions are(i) appearance-based recognition systems tend to be over-fitted to one depiction,(ii) models that explicitly encode spatial relations between parts are more robust,and(iii) recognition and non-photorealistic synthesis are related tasks.
文摘Polyaddition using isocyanate and polyol forms polyurethane elastomer (PUE). However, this method has rarely been applied to the construction of PUEs containing sucrose. Hence, the introduction of sucrose (disaccharide) as a cross-linker via polyaddition remains a challenging subject in polymer chemistry. Here, we report the synthesis of PUEs using an aromatic isocyanate (4,4’-diphenylmethane diisocyanate), polyols including a polyether polyol (polytetramethylene glycol) and two polyester polyols (polycaprolactone and polycarbonate diols), and sucrose as a crosslinker by a one-shot method. The PUEs containing sucrose were successfully produced. The use of sucrose was essential to obtain the desired PUEs containing sucrose units in the main chain.
文摘A novel lactic acid-based cross-linked poly（ester-amide） （LCPEA） was synthesized. The gel fraction of the LCPEA could be modulated by the reaction conditions and it affected the mechanical and thermal properties of the LCPEA. The tensile strength, elastic modulus and bend strength of the LCPEA of 65% gel fraction were 4.65, 136.55 and 39.63 MPa, respectively. The thermal decomposition temperature （50 wt%） of the LCPEA was around 410℃.
基金This work is supported in part by a General Research Fund grant(601211)from the Research Grant CouncilThe Hong Kong Special Administrative Region,P.R.China+1 种基金The Hong Kong Chiu Chow Chamber of Commence HKUST Scholarship for Ph.D.Study(Y.L.)the Department of Chemistry,HKUST.
文摘A pentamodule assembly approach has been established for total synthesis of the naturally occurring(-)-palmyrolide A and(+)-5,7-epi-palmyrolide A.By using the racemic tert-butyl carbinol-containing alkyl iodide,the two diastereoisomeric macrolides could be obtained from the same sequence of reactions,demonstrating the flexibility of the multimodule assembly strategy for diverted total synthesis.
基金ProjectsupportedbytheNationalNaturalScienceFoundationofChina (No .2 0 0 62 0 0 2 )
文摘Based on the different reactivity of selanyl and bromo groups,( E)-α- bromovinylselenides can undergo sequential cross coupling reactions with nucleophiles in the presence of transition metal complexes to form two carbon-carbon bonds in the same olefinic carbon leading to trisubstituted alkenes stereoselectively in good yields.
