Notoginsenoside R-111, a novel hexanordammarane glycoside was isolated from the roots of Panax nototginseng, as a minor constituent. Its structure was determined as 6-O-(beta -D-glucopyranosyl)-3 beta ,6 alpha ,12 bet...Notoginsenoside R-111, a novel hexanordammarane glycoside was isolated from the roots of Panax nototginseng, as a minor constituent. Its structure was determined as 6-O-(beta -D-glucopyranosyl)-3 beta ,6 alpha ,12 beta -trihydroxy-22,23,24,25,26,27-hexanordammaran-20-one(1), by means of spectroscopic methods.展开更多
On basis of two definitions that 1. an induced subgraph by a vertex vi E G and its neighbors in G is defined a vertex adjacent closed subgraph denoted by Qi （=G[V（Nvi）]）, with the vertex vi called the hub; 2. A r...On basis of two definitions that 1. an induced subgraph by a vertex vi E G and its neighbors in G is defined a vertex adjacent closed subgraph denoted by Qi （=G[V（Nvi）]）, with the vertex vi called the hub; 2. A r（k,1）-1 vertices connected graph is called a （k,l）-Ramsey graph denoted by RG（k,l）,if and only if 1. RG（k,l） contains only cliques of degree k-1, and its complement contains only cliques of degree l-l; 2. the intersect Qi∩Qj of any two nonadjacent vertices vi and vj of RG（k,1） contains Kk.2, and the intersect Qi∩Qj of any two nonadjacent vertices vi and vj of its complement RG（l,k） contains KI.2. Two theorems that theoreml ： the biggest clique in G is contained in some Qi of G, and theorem2： r（k,l）= [ V（RG（k,I）） I ＋1 are put forward and proved in this paper. With those definitions and theorems as well as analysis of property of chords a method for quick inspection and building RG（k,I） is proposed. Accordingly, RG（10,3） and its complement are built, which are respectively the strongly 29-regular graph and the strongly 10-regular graph on orders 40. We have tested RG（10,3） and its complement RG（3,10）,and gotten r（3,10）=41.展开更多
土壤呼吸是森林生态系统碳循环的关键环节,主要由土壤微生物呼吸和根系呼吸组成,二者对于氮添加及林下植被去除的响应可能不同。本研究以科尔沁沙地樟子松(Pinus sylvestris var. mongolica)人工林为对象,探讨了氮添加(N+)和林下植被去...土壤呼吸是森林生态系统碳循环的关键环节,主要由土壤微生物呼吸和根系呼吸组成,二者对于氮添加及林下植被去除的响应可能不同。本研究以科尔沁沙地樟子松(Pinus sylvestris var. mongolica)人工林为对象,探讨了氮添加(N+)和林下植被去除(U-)对一个生长季土壤呼吸及其组分的影响。结果表明:在沙地樟子松人工林中,土壤微生物呼吸是土壤呼吸的主要贡献者,其贡献率达85.53%;根系呼吸的贡献率相对较小,仅有14.47%;生长季内,土壤呼吸速率平均值为1.59(CK)、1.73(N+)、1.66(U-)、1.89(N+U-)μmol C·m-2·s-1,氮添加促进了生长季初期、末期的土壤呼吸,林下植被去除提高了生长季旺盛期土壤呼吸,而氮添加+林下植被去除同时作用下,整个生长季内土壤呼吸速率显著增强,且高于氮添加与林下植被去除的单独作用,说明氮添加+林下植被去除对于促进土壤呼吸存在叠加效应;土壤微生物呼吸速率为1.36(CK)、1.45(N+)、1.44(U-)、1.52(N+U-)μmol C·m-2·s-1,各种处理对土壤微生物呼吸均无显著影响;氮添加与林下植被去除均降低了土壤微生物呼吸的温度敏感性;各处理下根系呼吸R10变化幅度大于微生物呼吸,说明根系呼吸对各处理的响应要比土壤微生物呼吸更加敏感;受土壤含水量的影响,土壤呼吸与土壤温度表现不一样的变化规律,表明土壤含水量为该地区樟子松人工林土壤呼吸的重要调控因素。本研究为理解沙地樟子松人工林碳循环过程及其模型构建提供基础数据和科学依据。展开更多
文摘Notoginsenoside R-111, a novel hexanordammarane glycoside was isolated from the roots of Panax nototginseng, as a minor constituent. Its structure was determined as 6-O-(beta -D-glucopyranosyl)-3 beta ,6 alpha ,12 beta -trihydroxy-22,23,24,25,26,27-hexanordammaran-20-one(1), by means of spectroscopic methods.
文摘On basis of two definitions that 1. an induced subgraph by a vertex vi E G and its neighbors in G is defined a vertex adjacent closed subgraph denoted by Qi （=G[V（Nvi）]）, with the vertex vi called the hub; 2. A r（k,1）-1 vertices connected graph is called a （k,l）-Ramsey graph denoted by RG（k,l）,if and only if 1. RG（k,l） contains only cliques of degree k-1, and its complement contains only cliques of degree l-l; 2. the intersect Qi∩Qj of any two nonadjacent vertices vi and vj of RG（k,1） contains Kk.2, and the intersect Qi∩Qj of any two nonadjacent vertices vi and vj of its complement RG（l,k） contains KI.2. Two theorems that theoreml ： the biggest clique in G is contained in some Qi of G, and theorem2： r（k,l）= [ V（RG（k,I）） I ＋1 are put forward and proved in this paper. With those definitions and theorems as well as analysis of property of chords a method for quick inspection and building RG（k,I） is proposed. Accordingly, RG（10,3） and its complement are built, which are respectively the strongly 29-regular graph and the strongly 10-regular graph on orders 40. We have tested RG（10,3） and its complement RG（3,10）,and gotten r（3,10）=41.
