研究了农业生物质废弃物玉米芯热解产物炭质燃料的理化性能与裂解温度的关系及热解机理,用FT-IR,XRD,SEM对玉米芯炭进行表征,分析了化学组成、官能团分布、芳构化程度与温度的关系.结果表明,随热解温度升高,热解所得焦炭中固定碳和灰分...研究了农业生物质废弃物玉米芯热解产物炭质燃料的理化性能与裂解温度的关系及热解机理,用FT-IR,XRD,SEM对玉米芯炭进行表征,分析了化学组成、官能团分布、芳构化程度与温度的关系.结果表明,随热解温度升高,热解所得焦炭中固定碳和灰分增加,挥发分和水分减小,产率下降,热值先增加后减少,羰基和脂肪族官能团逐渐被破坏,结晶度和芳构化程度不断增强.500℃时,焦炭热值大于32 MJ/kg,产率大于24%,固定碳大于80%,灰分小于4%,且具有发达的孔洞结构,各项指标接近或优于市售燃料炭;233~533℃下玉米芯挥发最剧烈,具有1.5级反应的特征;热解温度从233~353℃上升至353~533℃时,表观活化能从68.15 k J/mol降至37.25 k J/mol.展开更多
Our present study was to prepare a biomass-supported adsorbents with high adsorptive capacity and high selectivity to prevent the accelerated eutrophication in water body.To this end,different metal hydroxide(La,Zr an...Our present study was to prepare a biomass-supported adsorbents with high adsorptive capacity and high selectivity to prevent the accelerated eutrophication in water body.To this end,different metal hydroxide(La,Zr and Fe)first was successfully loaded on chitosan microspheres.Then the quaternary ammonium group with different content was introduced into the adsorbent by polymerization.By comparison of adsorption properties,chitosanLa(OH)3-quaternary ammonium-20%(CS-La-N-20%)has strong adsorption to phosphate(160 mg/g)by immobilizing nano-sized La(OH)3 within a quaternary-aminated chitosan and it maintain high adsorption in the presence of salt ions.The pH results indicated that the CS-La-N-20%would effectively sequestrate phosphate over a wide pH range between 3 and 7 without significant La3+leaching.What’s more,adsorption capacity on the introduce of positively charged quanternary-aminated groups was significantly higher than that of the unmodified adsorbents at alkaline conditions.The column adsorption capacity reached 1300 bed volumes(BV)when phosphate concentration decreased until 0.5 mg/L at 6 BV/hr.The column adsorption/desorption reveals that no significant capacity loss is observed,indicating excellent stability and repeated use property.Characterizations revealed that phosphate adsorption on CS-La-N-20%through ligand exchange(impregnated nano-La(OH)3)and electrostatic attraction(positively charged quanternary-aminated groups).All the results suggested that CS-La-N-20%can serve as a promising adsorbent for preferable phosphate removal in realistic application.展开更多
It is not fully clear why there is a higher contribution of pluripotent stem cells （PSCs） to the chimera produced by injection of PSCs into 4-cell or 8-cell stage embryos compared with blastocyst injection. Here, we...It is not fully clear why there is a higher contribution of pluripotent stem cells （PSCs） to the chimera produced by injection of PSCs into 4-cell or 8-cell stage embryos compared with blastocyst injection. Here, we show that not only embryonic stem cells （ESCs） but also induced pluripotent stem cells （iPSCs） can generate F0 nearly 100% donor cell-derived mice by 4-cell stage embryo injection, and the approach has a ＂dose effect＂. Through an analysis of the PSC-secreted proteins, Activin A was found to impede epiblast （EPI） lineage development while promoting trophectoderm （TE） differentiation, resulting in replacement of the EPI lineage of host embryos with PSCs. Interestingly, the injection of ESCs into blastocysts cultured with Activin A （cultured from 4-cell stage to early blastocyst at E3.5） could increase the contribution of ESCs to the chimera. The results indicated that PSCs secrete protein Activin A to improvetheir EPI competency after injection into recipient embryos through influencing the development of mouse early embryos. This result is useful for optimizing the chimera production system and for a deep understand- ing of PSCs effects on early embryo development.展开更多
基金supported by the National Natural Science Foundation of China (52072142)the Program of Science and Technology Development Plan of Jilin Province of China (20230508071RC)。
文摘研究了农业生物质废弃物玉米芯热解产物炭质燃料的理化性能与裂解温度的关系及热解机理,用FT-IR,XRD,SEM对玉米芯炭进行表征,分析了化学组成、官能团分布、芳构化程度与温度的关系.结果表明,随热解温度升高,热解所得焦炭中固定碳和灰分增加,挥发分和水分减小,产率下降,热值先增加后减少,羰基和脂肪族官能团逐渐被破坏,结晶度和芳构化程度不断增强.500℃时,焦炭热值大于32 MJ/kg,产率大于24%,固定碳大于80%,灰分小于4%,且具有发达的孔洞结构,各项指标接近或优于市售燃料炭;233~533℃下玉米芯挥发最剧烈,具有1.5级反应的特征;热解温度从233~353℃上升至353~533℃时,表观活化能从68.15 k J/mol降至37.25 k J/mol.
基金supported by the National Natural Science Foundation of China(Nos.51978341 and 52070100)the Natural Science Foundation of Jiangsu Province of China(No.BK20190087)。
文摘Our present study was to prepare a biomass-supported adsorbents with high adsorptive capacity and high selectivity to prevent the accelerated eutrophication in water body.To this end,different metal hydroxide(La,Zr and Fe)first was successfully loaded on chitosan microspheres.Then the quaternary ammonium group with different content was introduced into the adsorbent by polymerization.By comparison of adsorption properties,chitosanLa(OH)3-quaternary ammonium-20%(CS-La-N-20%)has strong adsorption to phosphate(160 mg/g)by immobilizing nano-sized La(OH)3 within a quaternary-aminated chitosan and it maintain high adsorption in the presence of salt ions.The pH results indicated that the CS-La-N-20%would effectively sequestrate phosphate over a wide pH range between 3 and 7 without significant La3+leaching.What’s more,adsorption capacity on the introduce of positively charged quanternary-aminated groups was significantly higher than that of the unmodified adsorbents at alkaline conditions.The column adsorption capacity reached 1300 bed volumes(BV)when phosphate concentration decreased until 0.5 mg/L at 6 BV/hr.The column adsorption/desorption reveals that no significant capacity loss is observed,indicating excellent stability and repeated use property.Characterizations revealed that phosphate adsorption on CS-La-N-20%through ligand exchange(impregnated nano-La(OH)3)and electrostatic attraction(positively charged quanternary-aminated groups).All the results suggested that CS-La-N-20%can serve as a promising adsorbent for preferable phosphate removal in realistic application.
基金This work was supported by The National Key Research and Development Program of China （2016YFA0100202）, National Nat- ural Science Foundation of China （Grant Nos. 31571497 and31601941 ）, Beijing Natural Science Foundation of China （6152004）, The National Thousand Talents Program of China and Research Programs from the State Key Laboratory for Agrobiotechnology, China Agricultural University （grant numbers 2015SKLAB1-4, 2017SKLAB1-2）.
文摘It is not fully clear why there is a higher contribution of pluripotent stem cells （PSCs） to the chimera produced by injection of PSCs into 4-cell or 8-cell stage embryos compared with blastocyst injection. Here, we show that not only embryonic stem cells （ESCs） but also induced pluripotent stem cells （iPSCs） can generate F0 nearly 100% donor cell-derived mice by 4-cell stage embryo injection, and the approach has a ＂dose effect＂. Through an analysis of the PSC-secreted proteins, Activin A was found to impede epiblast （EPI） lineage development while promoting trophectoderm （TE） differentiation, resulting in replacement of the EPI lineage of host embryos with PSCs. Interestingly, the injection of ESCs into blastocysts cultured with Activin A （cultured from 4-cell stage to early blastocyst at E3.5） could increase the contribution of ESCs to the chimera. The results indicated that PSCs secrete protein Activin A to improvetheir EPI competency after injection into recipient embryos through influencing the development of mouse early embryos. This result is useful for optimizing the chimera production system and for a deep understand- ing of PSCs effects on early embryo development.
