[Purpose]To research upon the structure and pyrolysis of cotton stalk.[Method] In this paper thermogravimetric analysis is adopted to study pyrolysis characteristics on the longitudinal direction of cotton stalk（the ...[Purpose]To research upon the structure and pyrolysis of cotton stalk.[Method] In this paper thermogravimetric analysis is adopted to study pyrolysis characteristics on the longitudinal direction of cotton stalk（the stick and the root）and on the traverse direction（the cuticle,cortex and medulla）.[Result] Cotton stalk is a material of uneven and irregular texture,and there are great differences in the structure of all these parts on the longitudinal and traverse directions,especially in the contents of different components in each layer.The reaction in the stick and root becomes violent along with the increase in the rising rate of temperature,and carbon yield rate decreases in turn.Besides with the same rising rate of temperature,carbon yield rate of cotton stick is higher than the one of cotton root.Carbon yield rates of cuticle,cortex and medulla decrease in turn while the violence of the reaction in cuticle is less severe than in cortex and medulla.[Conclusion] It has provided theoretical basis for obtaining activated carbon technology of cotton stick.展开更多
Pretreatment of lespedeza stalks by steam explosion has been studied. The results indicate that steam-exploded pretreatment has strong effects on physical features, morphology, crystallinity, and composition of lesped...Pretreatment of lespedeza stalks by steam explosion has been studied. The results indicate that steam-exploded pretreatment has strong effects on physical features, morphology, crystallinity, and composition of lespedeza stalks as shown by scanning electron microscopy （SEM）, infrared （IR）, and X-ray diffraction spectrometry methods. After steam explosion, the cellulose and lignin contents of lespedeza stalks varied only slightly, but the hemicellulose content had decreased from 29.34% to 7.48%. The cellulose obtained by steam-exploded pretreatment had a higher degree of crystallinity than that of the raw material. At the explosion condition of 2.25 MPa and 4 min, lignocellulose is easier to hydrolyze by enzyme than the original lignocellulose. The concentration of reduced sugar in the hydrolyzate liquid increased from 71.77 to 162.84 g·L^-1.展开更多
The research focuses on the study of anatomical and morphological stalk structure ofsoya interspecific hybrids of the third generation （F3） between （Glycine max （L.） Merr.） and G. soja Sieb. et Zucc. in comparis...The research focuses on the study of anatomical and morphological stalk structure ofsoya interspecific hybrids of the third generation （F3） between （Glycine max （L.） Merr.） and G. soja Sieb. et Zucc. in comparison with parent plant species. The parent plant species and interspecific hybrids were sowed and grew under similar conditions. The similarity of the anatomic structure of stalks of cultivated plants and Glycine soja （wild soya） proves the hypothesis the studied species have the same origin. However, the obtained results show the considerable degree of phylogenetic dissociation between the studied soya species. Interspecific hybrids inherit from G. soja the ability to high intensive growth. The G. soja use in practical selective breeding is of great interest.展开更多
A steam explosion pretreatment, which is one of the best ways of pretreating plant stalk, is applied at various severities to corn stalk. It could effectively modify the super-molecular structure of corn stalk and def...A steam explosion pretreatment, which is one of the best ways of pretreating plant stalk, is applied at various severities to corn stalk. It could effectively modify the super-molecular structure of corn stalk and defibrating corn stalk into individual components. The relationship between yield of reducing sugar and the operating conditions, including temperature, pressure of steam explosion pretreatment and acidity, is also established. Experimental results prove that the steam explosion substantially increases the yield of reducing sugar, and the optimal condition for steam explosion is as follows: the pressure is 2.0 MPa, the pressure-retaining time 300 s, the initial acid concentration 1% and the acid treatment time 24 h.展开更多
与股骨接触的假体柄是人工髋关节的主要部件,在全髋置换手术中起着重要作用。采用变密度固体各向同性材料惩罚(Solid Isotropic Material with Penalization,SIMP)拓扑优化方法和多尺度的并行拓扑优化方法,分别得到A型和B型两种股骨柄结...与股骨接触的假体柄是人工髋关节的主要部件,在全髋置换手术中起着重要作用。采用变密度固体各向同性材料惩罚(Solid Isotropic Material with Penalization,SIMP)拓扑优化方法和多尺度的并行拓扑优化方法,分别得到A型和B型两种股骨柄结构,并将股骨柄结构柔度变化幅度作为对比指标,比较了两种股骨柄对载荷方向变化的敏感度。利用有限元方法对A型股骨柄和B型股骨柄进行多工况下所对应股骨的应力分析。研究结果表明,在3种工况下,A型股骨柄和B型股骨柄对股骨的平均应力分别为14.80、22.55、16.94 MPa和10.89、20.92、16.50 MPa。对B型股骨柄进行压力加载试验,试验结果表明,在内侧测点,试验的应变值与仿真值的平均误差为-1682με,平均相对误差为20.3%;在外侧测点,试验的应变值与仿真值的平均误差为1281με,平均相对误差为19.5%。该方法为股骨假体柄结构的可靠性设计提供了有效参考。展开更多
利用湿筛法进行土壤团聚体分组(>2、2～0.25、0.25～0.053、<0.053 mm粒级),研究了其添加不同用量玉米秸秆,25℃恒温室内培养对团聚体中胡敏酸数量和结构特征的影响。结果表明:添加玉米秸秆培养后,土壤团聚体2～0.25 mm和>2 m...利用湿筛法进行土壤团聚体分组(>2、2～0.25、0.25～0.053、<0.053 mm粒级),研究了其添加不同用量玉米秸秆,25℃恒温室内培养对团聚体中胡敏酸数量和结构特征的影响。结果表明:添加玉米秸秆培养后,土壤团聚体2～0.25 mm和>2 mm粒级成为优势粒级,平均含量分别占51.41%和34.12%,其全碳含量为10.15～25.74 g kg-1,胡敏酸(HA)绝对含量为4.06～5.79 g kg-1,明显高于对照CK的9.79～10.48 g kg-1和3.70 g kg-1,并随玉米秸秆用量的增加而增大;各处理胡敏酸C/H及高温/中温比值均低于CK处理,并随玉米秸秆用量的增加逐渐减小,说明随玉米秸秆用量的增加使HA分子缩合度降低,结构趋于简单化。展开更多
文摘[Purpose]To research upon the structure and pyrolysis of cotton stalk.[Method] In this paper thermogravimetric analysis is adopted to study pyrolysis characteristics on the longitudinal direction of cotton stalk（the stick and the root）and on the traverse direction（the cuticle,cortex and medulla）.[Result] Cotton stalk is a material of uneven and irregular texture,and there are great differences in the structure of all these parts on the longitudinal and traverse directions,especially in the contents of different components in each layer.The reaction in the stick and root becomes violent along with the increase in the rising rate of temperature,and carbon yield rate decreases in turn.Besides with the same rising rate of temperature,carbon yield rate of cotton stick is higher than the one of cotton root.Carbon yield rates of cuticle,cortex and medulla decrease in turn while the violence of the reaction in cuticle is less severe than in cortex and medulla.[Conclusion] It has provided theoretical basis for obtaining activated carbon technology of cotton stick.
文摘Pretreatment of lespedeza stalks by steam explosion has been studied. The results indicate that steam-exploded pretreatment has strong effects on physical features, morphology, crystallinity, and composition of lespedeza stalks as shown by scanning electron microscopy （SEM）, infrared （IR）, and X-ray diffraction spectrometry methods. After steam explosion, the cellulose and lignin contents of lespedeza stalks varied only slightly, but the hemicellulose content had decreased from 29.34% to 7.48%. The cellulose obtained by steam-exploded pretreatment had a higher degree of crystallinity than that of the raw material. At the explosion condition of 2.25 MPa and 4 min, lignocellulose is easier to hydrolyze by enzyme than the original lignocellulose. The concentration of reduced sugar in the hydrolyzate liquid increased from 71.77 to 162.84 g·L^-1.
文摘The research focuses on the study of anatomical and morphological stalk structure ofsoya interspecific hybrids of the third generation （F3） between （Glycine max （L.） Merr.） and G. soja Sieb. et Zucc. in comparison with parent plant species. The parent plant species and interspecific hybrids were sowed and grew under similar conditions. The similarity of the anatomic structure of stalks of cultivated plants and Glycine soja （wild soya） proves the hypothesis the studied species have the same origin. However, the obtained results show the considerable degree of phylogenetic dissociation between the studied soya species. Interspecific hybrids inherit from G. soja the ability to high intensive growth. The G. soja use in practical selective breeding is of great interest.
文摘A steam explosion pretreatment, which is one of the best ways of pretreating plant stalk, is applied at various severities to corn stalk. It could effectively modify the super-molecular structure of corn stalk and defibrating corn stalk into individual components. The relationship between yield of reducing sugar and the operating conditions, including temperature, pressure of steam explosion pretreatment and acidity, is also established. Experimental results prove that the steam explosion substantially increases the yield of reducing sugar, and the optimal condition for steam explosion is as follows: the pressure is 2.0 MPa, the pressure-retaining time 300 s, the initial acid concentration 1% and the acid treatment time 24 h.
文摘与股骨接触的假体柄是人工髋关节的主要部件,在全髋置换手术中起着重要作用。采用变密度固体各向同性材料惩罚(Solid Isotropic Material with Penalization,SIMP)拓扑优化方法和多尺度的并行拓扑优化方法,分别得到A型和B型两种股骨柄结构,并将股骨柄结构柔度变化幅度作为对比指标,比较了两种股骨柄对载荷方向变化的敏感度。利用有限元方法对A型股骨柄和B型股骨柄进行多工况下所对应股骨的应力分析。研究结果表明,在3种工况下,A型股骨柄和B型股骨柄对股骨的平均应力分别为14.80、22.55、16.94 MPa和10.89、20.92、16.50 MPa。对B型股骨柄进行压力加载试验,试验结果表明,在内侧测点,试验的应变值与仿真值的平均误差为-1682με,平均相对误差为20.3%;在外侧测点,试验的应变值与仿真值的平均误差为1281με,平均相对误差为19.5%。该方法为股骨假体柄结构的可靠性设计提供了有效参考。
文摘利用湿筛法进行土壤团聚体分组(>2、2～0.25、0.25～0.053、<0.053 mm粒级),研究了其添加不同用量玉米秸秆,25℃恒温室内培养对团聚体中胡敏酸数量和结构特征的影响。结果表明:添加玉米秸秆培养后,土壤团聚体2～0.25 mm和>2 mm粒级成为优势粒级,平均含量分别占51.41%和34.12%,其全碳含量为10.15～25.74 g kg-1,胡敏酸(HA)绝对含量为4.06～5.79 g kg-1,明显高于对照CK的9.79～10.48 g kg-1和3.70 g kg-1,并随玉米秸秆用量的增加而增大;各处理胡敏酸C/H及高温/中温比值均低于CK处理,并随玉米秸秆用量的增加逐渐减小,说明随玉米秸秆用量的增加使HA分子缩合度降低,结构趋于简单化。
