The pretreatment for the removal of small molecules from poly(acrylic acid) sodium (PAAS) solution by continuous diafiltration was investigated using ultrafiltration membrane. The effects of PAAS concentration, pH, tr...The pretreatment for the removal of small molecules from poly(acrylic acid) sodium (PAAS) solution by continuous diafiltration was investigated using ultrafiltration membrane. The effects of PAAS concentration, pH, trans-membrane pressure and pretreatment time on the permeate concentration and permeate flux were studied. The results show that the necessary pretreatment time (NPT) increases with PAAS concentration, decreases with TMP. The change trend of permeate flux with time is affected by pH. The permeate fluxes rapidly decrease from the start, and then increase gradually to stable values at pH 5.0, pH 7.0 and pH 9.3. However, it decreases gradually with time till a state value at pH 3.0 (iso-electric point, IEP). The removal of small molecules is easy at pH greater than iso-electric point (IEP). The change of filtration potential with time indicates the similar trend to that of permeation concentration, but the former is more convenient for indication of NPT.展开更多
Stable and monodispersed silver nanoparticles were produced through a mild,convenient,one-pot method based on the reduction of silver nitrate in the presence of poly(amic acid) (PAA) as a stabilizer.The surface plasma...Stable and monodispersed silver nanoparticles were produced through a mild,convenient,one-pot method based on the reduction of silver nitrate in the presence of poly(amic acid) (PAA) as a stabilizer.The surface plasma band transition was monitored along with time in the reaction mixture for three sets of experiments by ultraviolet-visible spectroscopy.Analysis of the data with the Avrami equation yielded n exponent with values between 0.5 and 1.5,demonstrating three-dimensional heterogeneous nucleation and diffusion-controlled growth,accompanied by soft impingement effect.XRD and TEM analyses show a softly agglomerated polycrystalline state and a nearly spherical morphology (<50 nm) of nanoparticles.The FT-IR result indicates that the PAA molecular structure could be hardly influenced by the formation of nanoparticles.展开更多
The redox initiation system for polyacrylate sodium of high molecular mass was designed and its effect with varying component dosage on the degree of polymerization was investigated. The results show that the proper t...The redox initiation system for polyacrylate sodium of high molecular mass was designed and its effect with varying component dosage on the degree of polymerization was investigated. The results show that the proper type and amount of inorganic salt, as well as amine initiator, are conductive to the increase of degree of polymerization. The fine ingredient of the initiation system is as follows:the dosages of amine, persulphate and inorganic salt are 0.75%, 0.10% and 1.00% by mass based on acryl acid respectively, the molar ratio of sulphite to the persulphate is 1:1. Under such conditions the degree of polyacrylate can reach 7.43×107 with a acceptable polymerization time for industrial production.展开更多
探究聚-γ-谷氨酸(γ-PGA)对水稻产量、品质和养分吸收的影响,为高产优质、养分高效利用的水稻栽培技术提供理论依据和技术参考。于2022年和2023年在湖北省武穴市花桥镇开展田间试验,采用随机完全区组设计,包括黑籼稻(B)、冈特优8024(R...探究聚-γ-谷氨酸(γ-PGA)对水稻产量、品质和养分吸收的影响,为高产优质、养分高效利用的水稻栽培技术提供理论依据和技术参考。于2022年和2023年在湖北省武穴市花桥镇开展田间试验,采用随机完全区组设计,包括黑籼稻(B)、冈特优8024(R)和黄华占(H)3个水稻品种,和不施加γ-PGA发酵液(P0)和施加25 kg hm^(-2)γ-PGA发酵液(P1)2种γ-PGA处理方式,分析了水稻干物质量、植株氮磷素积累量、产量、稻米外观品质、籽粒蛋白质含量和直链淀粉含量。结果表明,2022年施加γ-PGA对水稻产量影响显著,P1处理较P0水稻产量增加3.2%~10.8%;2023年施加γ-PGA对水稻产量无显著影响。施加γ-PGA的品种B和R的干物质量显著高于不施γ-PGA处理,BP1处理较BP0齐穗期干物质量显著增加7.5%~8.5%,成熟期干物质量显著增加5.9%~7.2%;RP1处理较RP0齐穗期干物质量显著增加8.5%~8.8%,成熟期干物质量显著增加3.3%~3.5%。施加γ-PGA对品种H的干物质量无显著影响。施加γ-PGA能显著提高水稻的氮素和磷素积累量,P1处理较P0齐穗期氮素积累量显著增加12.5%~19.0%,磷素积累量显著增加13.4%~20.3%;成熟期氮素积累量显著增加7.2%~16.5%,磷素积累量显著增加9.2%~29.0%。施用γ-PGA能显著提高稻米直链淀粉和蛋白质含量,降低胶稠度、垩白度,但对粒长、粒宽、碱消值无显著影响。因此,施用γ-PGA显著提高水稻植株干物质量和氮、磷素积累量,改善稻米品质。展开更多
基金Projects(21176264,21476265)supported by the National Natural Science Foundation of China
文摘The pretreatment for the removal of small molecules from poly(acrylic acid) sodium (PAAS) solution by continuous diafiltration was investigated using ultrafiltration membrane. The effects of PAAS concentration, pH, trans-membrane pressure and pretreatment time on the permeate concentration and permeate flux were studied. The results show that the necessary pretreatment time (NPT) increases with PAAS concentration, decreases with TMP. The change trend of permeate flux with time is affected by pH. The permeate fluxes rapidly decrease from the start, and then increase gradually to stable values at pH 5.0, pH 7.0 and pH 9.3. However, it decreases gradually with time till a state value at pH 3.0 (iso-electric point, IEP). The removal of small molecules is easy at pH greater than iso-electric point (IEP). The change of filtration potential with time indicates the similar trend to that of permeation concentration, but the former is more convenient for indication of NPT.
基金Project(10JJ5057)supported by the Hunan Provincial Natural Science Foundation of China
文摘Stable and monodispersed silver nanoparticles were produced through a mild,convenient,one-pot method based on the reduction of silver nitrate in the presence of poly(amic acid) (PAA) as a stabilizer.The surface plasma band transition was monitored along with time in the reaction mixture for three sets of experiments by ultraviolet-visible spectroscopy.Analysis of the data with the Avrami equation yielded n exponent with values between 0.5 and 1.5,demonstrating three-dimensional heterogeneous nucleation and diffusion-controlled growth,accompanied by soft impingement effect.XRD and TEM analyses show a softly agglomerated polycrystalline state and a nearly spherical morphology (<50 nm) of nanoparticles.The FT-IR result indicates that the PAA molecular structure could be hardly influenced by the formation of nanoparticles.
基金Project(G199906490 2) supported by the National Key Fundamental Research and Development Program of China
文摘The redox initiation system for polyacrylate sodium of high molecular mass was designed and its effect with varying component dosage on the degree of polymerization was investigated. The results show that the proper type and amount of inorganic salt, as well as amine initiator, are conductive to the increase of degree of polymerization. The fine ingredient of the initiation system is as follows:the dosages of amine, persulphate and inorganic salt are 0.75%, 0.10% and 1.00% by mass based on acryl acid respectively, the molar ratio of sulphite to the persulphate is 1:1. Under such conditions the degree of polyacrylate can reach 7.43×107 with a acceptable polymerization time for industrial production.
文摘探究聚-γ-谷氨酸(γ-PGA)对水稻产量、品质和养分吸收的影响,为高产优质、养分高效利用的水稻栽培技术提供理论依据和技术参考。于2022年和2023年在湖北省武穴市花桥镇开展田间试验,采用随机完全区组设计,包括黑籼稻(B)、冈特优8024(R)和黄华占(H)3个水稻品种,和不施加γ-PGA发酵液(P0)和施加25 kg hm^(-2)γ-PGA发酵液(P1)2种γ-PGA处理方式,分析了水稻干物质量、植株氮磷素积累量、产量、稻米外观品质、籽粒蛋白质含量和直链淀粉含量。结果表明,2022年施加γ-PGA对水稻产量影响显著,P1处理较P0水稻产量增加3.2%~10.8%;2023年施加γ-PGA对水稻产量无显著影响。施加γ-PGA的品种B和R的干物质量显著高于不施γ-PGA处理,BP1处理较BP0齐穗期干物质量显著增加7.5%~8.5%,成熟期干物质量显著增加5.9%~7.2%;RP1处理较RP0齐穗期干物质量显著增加8.5%~8.8%,成熟期干物质量显著增加3.3%~3.5%。施加γ-PGA对品种H的干物质量无显著影响。施加γ-PGA能显著提高水稻的氮素和磷素积累量,P1处理较P0齐穗期氮素积累量显著增加12.5%~19.0%,磷素积累量显著增加13.4%~20.3%;成熟期氮素积累量显著增加7.2%~16.5%,磷素积累量显著增加9.2%~29.0%。施用γ-PGA能显著提高稻米直链淀粉和蛋白质含量,降低胶稠度、垩白度,但对粒长、粒宽、碱消值无显著影响。因此,施用γ-PGA显著提高水稻植株干物质量和氮、磷素积累量,改善稻米品质。
