A new unified analytical solution is presented for predicting the range of plastic zone and stress distributions around a deep circular tunnel in a homogeneous isotropic continuous medium. The rock mass, grouting zone...A new unified analytical solution is presented for predicting the range of plastic zone and stress distributions around a deep circular tunnel in a homogeneous isotropic continuous medium. The rock mass, grouting zone and lining are assumed as elastic-perfectly plastic and governed by the unified strength theory(UST). This new solution has made it possible to consider the interaction between seepage pressure, lining, grouting and rock mass, and the intermediate principal stress effect together. Moreover, parametric analysis is carried out to identify the influence of the related parameters on the plastic zone radius. Under the given conditions, the results show that the plastic zone radius decreases with an increasing cohesion, internal friction angle and hydraulic conductivity of lining and unified failure criterion parameter, respectively; whereas the plastic zone radius increases with the growth of elasticity modulus of lining. Comparison of results from the new solution and the other published one shows well agreement and provides confidence in the new solution proposed.展开更多
In perspective of breeding high-yield hybrid pepper varieties, combining ability analysis of net photosynthesis rate at different phases of flowering and fruit setting in pepper was made with 15 cross combinations fro...In perspective of breeding high-yield hybrid pepper varieties, combining ability analysis of net photosynthesis rate at different phases of flowering and fruit setting in pepper was made with 15 cross combinations from 6 parents by （1/2） n （n- 1） diallel crosses. There are relatively large differences not only in general combining ability （GCA） effect among different parents and at different phases of flowering and fruit setting, but also in specific combining ability （SCA） effect among different hybrids. There are relatively large GCA effects in late parents but relatively less GCA effects in early parents. No obvious laws have been found in the relationship between SCA effects and maturity of hybrids. Variances of SCA are larger than those of GCA. Heritability is less but influence of environment is larger. Correlation analysis of combining ability between net photosynthesis rate and agronomic character or resistances to main diseases has showed that correlation coefficients of GCA are relatively large at the medium phase and the late phase of flowering and fruit setting. Net photosynthesis rate is more relative to leaf characters and fruit characters. Correlation coefficients of SCA are relatively large at the early phase and the late phase of flowering and fruit setting. Net photosynthesis rate is more relative to leaf characters and plant characters at the early phase but to plant characters and fruit characters at the late phase. Correlation coefficients of SCA between net photosynthesis rate and resistances to main diseases are larger than those of GCA. The combining abilities of net photosynthesis rate at different phases of flowering and fruit setting are positively correlated with those of yield per plant. The combining ability is an important parameter of breeding of high photosynthesis hybrid pepper varieties.展开更多
Flixweed（Descurainia sophia L.） is a problematic and widespread weed in winter wheat fields and has been controlled by tribenuron-methyl for more than twenty years in China. In this study, a flixweed accession（Hebe...Flixweed（Descurainia sophia L.） is a problematic and widespread weed in winter wheat fields and has been controlled by tribenuron-methyl for more than twenty years in China. In this study, a flixweed accession（Hebei 25, HB25） with an Asp-376-Glu mutation in acetohydroxy acid synthase（AHAS） was identified and purified. The purified HB25 accession（p HB25） developed 758.1-fold resistance to tribenuron-methyl and exhibited obvious cross-resistance to four AHAS-inhibiting herbicides. The resistant/susceptible（R/S） ratios of 50% plant growth reduction（GR_（50）） to herbicides of halosulfuron-methyl, flumetsulam, imazethapyr and pyribenzoxim were 346.1, 15.7, 8.1 and 7.1, respectively. The reduced AHAS sensitivities to four different AHAS-inhibiting herbicides, which were caused by the Asp-376-Glu mutation, were responsible for the resistance and cross-resistance to AHAS-inhibiting herbicides. The R/S ratios of 50% inhibition of AHAS activity（I50） to tribenuron-methyl, halosulfuron-methyl, flumetsulam, imazethapyr and pyribenzoxim were 844.5, 532.9, 74.5, 13.3 and 5.5, respectively. The results of AHAS activity in vitro were highly correlated with that of whole-plant response experiments.展开更多
为探究王草(Pennisetum purpureum×P.americana)青贮饲料中优质乳酸菌的主要种类及其性质,本研究以‘热研4号’王草为对象,用传统微生物培养、生理生化特征分析与16S r RNA基因序列分析相结合的方法对王草青贮饲料上附着的乳酸菌...为探究王草(Pennisetum purpureum×P.americana)青贮饲料中优质乳酸菌的主要种类及其性质,本研究以‘热研4号’王草为对象,用传统微生物培养、生理生化特征分析与16S r RNA基因序列分析相结合的方法对王草青贮饲料上附着的乳酸菌进行了分离、培养、筛选和鉴定。研究结果表明:王草青贮饲料中分离得到了117株乳酸菌,能在8 h内快速繁殖和产酸,没有迟滞期,培养24 h可使发酵液pH值降至3.89~4.22的菌株有4株,它们分别为戊糖片球菌(K1和K2)、乳酸片球菌(K3)和粪肠球菌(K4);但只有K1,K2和K4这3株菌株在培养基的NaCl浓度为3.5%和7.5%,pH值为3.5~8.0,15~45℃的环境中均能良好生长,均能利用至少8种碳源;其中K4菌株不但能利用15种碳源,还能耐受50℃高温。综合以上考虑,本试验筛选出的戊糖片球菌(K1,K2)和粪肠球菌(K4)具有成为王草青贮饲料生产使用的优质乳酸菌添加剂的潜力。展开更多
基金Project(51378309)supported by National Natural Science Foundation of China
文摘A new unified analytical solution is presented for predicting the range of plastic zone and stress distributions around a deep circular tunnel in a homogeneous isotropic continuous medium. The rock mass, grouting zone and lining are assumed as elastic-perfectly plastic and governed by the unified strength theory(UST). This new solution has made it possible to consider the interaction between seepage pressure, lining, grouting and rock mass, and the intermediate principal stress effect together. Moreover, parametric analysis is carried out to identify the influence of the related parameters on the plastic zone radius. Under the given conditions, the results show that the plastic zone radius decreases with an increasing cohesion, internal friction angle and hydraulic conductivity of lining and unified failure criterion parameter, respectively; whereas the plastic zone radius increases with the growth of elasticity modulus of lining. Comparison of results from the new solution and the other published one shows well agreement and provides confidence in the new solution proposed.
基金Project supported by the Knowledge Innovation Project of the Chinese Academy of Sciences (No.KZCX2-YW-416)National NaturM Science Foundation of China (No.90411020)
文摘这研究的目的是调查更高的 CO2 集中的效果(500 和 700 μ m ol 摩尔 ? 1 ) 在全部的土壤呼吸和到全部的土壤呼吸的根呼吸的贡献上的空气在 Pinus sylvestris var 的幼苗生长期间。sylvestriformis。在从 1999 ～ 2003 的四生长期(5 月 10 月) 期间，幼苗在开顶的房间暴露于 CO2 的提高的集中。根呼吸的全部的土壤呼吸和贡献在 6 月 15 日用一个 LI-6400-09 土壤 CO2 流动房间被测量并且 2003 年 10 月 8 日。到从全部的土壤呼吸的分开的根呼吸，三 PVC 柱体被插入进在每个房间的土壤约 30 厘米深。有显著日报在 6 月 15 日在空和土壤温度中变化。没有根的全部的土壤呼吸和土壤呼吸出现了一强壮日报模式，在下午从以前增加日出到大约 14:00 然后在下一日出前减少。有切断的根的吝啬的全部的土壤呼吸和吝啬的土壤呼吸的增加都没在 2003 年 6 月 15 日在提高的 CO2 处理下面被观察，作为与有周围的 CO2 的田野和控制房间相比。在 2003 年 10 月 8 日，然而，有根的全部的土壤呼吸和土壤呼吸在田野切断了是比在控制的那些低的并且提高了 CO2 房间。在 2003 年 6 月 15 日测量的根呼吸的吝啬的贡献，从 8.3% ～ 30.5% 并且在 2003 年 10 月 8 日，从 20.6% ～ 48.6% 。
文摘In perspective of breeding high-yield hybrid pepper varieties, combining ability analysis of net photosynthesis rate at different phases of flowering and fruit setting in pepper was made with 15 cross combinations from 6 parents by （1/2） n （n- 1） diallel crosses. There are relatively large differences not only in general combining ability （GCA） effect among different parents and at different phases of flowering and fruit setting, but also in specific combining ability （SCA） effect among different hybrids. There are relatively large GCA effects in late parents but relatively less GCA effects in early parents. No obvious laws have been found in the relationship between SCA effects and maturity of hybrids. Variances of SCA are larger than those of GCA. Heritability is less but influence of environment is larger. Correlation analysis of combining ability between net photosynthesis rate and agronomic character or resistances to main diseases has showed that correlation coefficients of GCA are relatively large at the medium phase and the late phase of flowering and fruit setting. Net photosynthesis rate is more relative to leaf characters and fruit characters. Correlation coefficients of SCA are relatively large at the early phase and the late phase of flowering and fruit setting. Net photosynthesis rate is more relative to leaf characters and plant characters at the early phase but to plant characters and fruit characters at the late phase. Correlation coefficients of SCA between net photosynthesis rate and resistances to main diseases are larger than those of GCA. The combining abilities of net photosynthesis rate at different phases of flowering and fruit setting are positively correlated with those of yield per plant. The combining ability is an important parameter of breeding of high photosynthesis hybrid pepper varieties.
基金sponsored by the Special Fund for Agro-scientific Research in the Public Interest,China(201303031)
文摘Flixweed（Descurainia sophia L.） is a problematic and widespread weed in winter wheat fields and has been controlled by tribenuron-methyl for more than twenty years in China. In this study, a flixweed accession（Hebei 25, HB25） with an Asp-376-Glu mutation in acetohydroxy acid synthase（AHAS） was identified and purified. The purified HB25 accession（p HB25） developed 758.1-fold resistance to tribenuron-methyl and exhibited obvious cross-resistance to four AHAS-inhibiting herbicides. The resistant/susceptible（R/S） ratios of 50% plant growth reduction（GR_（50）） to herbicides of halosulfuron-methyl, flumetsulam, imazethapyr and pyribenzoxim were 346.1, 15.7, 8.1 and 7.1, respectively. The reduced AHAS sensitivities to four different AHAS-inhibiting herbicides, which were caused by the Asp-376-Glu mutation, were responsible for the resistance and cross-resistance to AHAS-inhibiting herbicides. The R/S ratios of 50% inhibition of AHAS activity（I50） to tribenuron-methyl, halosulfuron-methyl, flumetsulam, imazethapyr and pyribenzoxim were 844.5, 532.9, 74.5, 13.3 and 5.5, respectively. The results of AHAS activity in vitro were highly correlated with that of whole-plant response experiments.
