The cycloaddition of N-acyliminium cations with some deactivated alkenes such as α,β-unsaturate ketones and esters has been investigated. In most cases, the N-acyliminium cations produced from 3-hydroxy-2-arylisoind...The cycloaddition of N-acyliminium cations with some deactivated alkenes such as α,β-unsaturate ketones and esters has been investigated. In most cases, the N-acyliminium cations produced from 3-hydroxy-2-arylisoindol-1-ones in the presence of BFa.OEt2 could be reacted with α,β-unsaturated ketones and esters to afford stereoselectively the cycloaddition products 6-acylisoindolo[2,1- a]quinolin-11-ones in moderate to high yields. C 2009 Wei Zhang. Published by Elsevier B.V, on behalf of Chinese Chemical Society. All rights reserved.展开更多
The stereoselective synthesis of 2-chloro-4-substituted-phenyl-5,5-dimethyl-1,3,2-dioxaphosphorinan-2-(thi)ones is described. Only single trans-isomers were obtained when 1-substituted-phenyl-2,2-dimethyl-1,3-propaned...The stereoselective synthesis of 2-chloro-4-substituted-phenyl-5,5-dimethyl-1,3,2-dioxaphosphorinan-2-(thi)ones is described. Only single trans-isomers were obtained when 1-substituted-phenyl-2,2-dimethyl-1,3-propanediols (1) reacted with POCl3. But the stereoselectivity of cyclization reaction between (1) and PSCl3 depended greatly upon the reaction condition. The configurational assignments and the ratio of cis-/trans- diastereoisomers of the products were performed on the basis of (HNMR)-H-1, (PNMR)-P-31 and IR spectra and confirmed by X-ray diffraction analyses.展开更多
Entry into WTO means that Chinese enterprises, which were deeply influenced by planned economy, will scramble for profits with those world famous transnational companies of strong strength. Facing such competitive sit...Entry into WTO means that Chinese enterprises, which were deeply influenced by planned economy, will scramble for profits with those world famous transnational companies of strong strength. Facing such competitive situation, how can China cultivate more famous and strong Chinese transnational companies on the international market? This is a question for many economists and enterprisers to make serious research.展开更多
one通常可用来替代上文中出现过的可数名词或以可数名词为中心词的整个名词词组,既可指人,也可指物。例如:The speed of the new machine ismuch greater than that of the oldone.There was an old man and ayoung one there.one的复...one通常可用来替代上文中出现过的可数名词或以可数名词为中心词的整个名词词组,既可指人,也可指物。例如:The speed of the new machine ismuch greater than that of the oldone.There was an old man and ayoung one there.one的复数形式是ones,只能替代复数可数名词,既可指人,也可指物。展开更多
Memory enables organisms to encode,store,and retrieve information essential for interacting with and adapting to a dynamic environment.As an internal representation of the external world,memory serves as a crucial bri...Memory enables organisms to encode,store,and retrieve information essential for interacting with and adapting to a dynamic environment.As an internal representation of the external world,memory serves as a crucial bridge between past experiences and future behaviors.However,the brain continuously forms new memories,raising the question of how new memories are integrated without disrupting previously formed ones.展开更多
Thirteen new 2 alkylaminoimidazolones (4) were rapidly synthesized by a new solution phase parallel synthetic method, which includes aza Wittig reaction of iminophosphorane (1) with aromatic isocyanate to give carb...Thirteen new 2 alkylaminoimidazolones (4) were rapidly synthesized by a new solution phase parallel synthetic method, which includes aza Wittig reaction of iminophosphorane (1) with aromatic isocyanate to give carbodi imide (2) and subsequent reaction of 2 with various aliphatic primary amine in a parallel fashion. The products were confirmed by 1H NMR, MS, IR and X ray crystallographic analysis. The unusual selectivity of the cyclization was probably due to the geometry of the guanidine intermediate.展开更多
Using the method of intracellular injection of horseradish peroxidase, the arborizations of several neurones with different functions in the segmental ganglia of the leech Whitmania pigra are investigated. Comparison ...Using the method of intracellular injection of horseradish peroxidase, the arborizations of several neurones with different functions in the segmental ganglia of the leech Whitmania pigra are investigated. Comparison is made in each kind of neurones in order to verify their typical pattern. Results show that the morphology of the axonal arbors of identified neurones has an accurate similarity within and among the individuals of the leech, and the axonal arborizations of the bilaterally identified neurones in the same ganglion have a stable symmetry. The possible reasons of the formation and its functional significance of the symmetrical nervous system are discussed.展开更多
In the early winter of 2017-18,Xie Yuan,vice-president of the Chinese People’s Association for Friendship with Foreign Countries,visited Belgium to award the title of Friendship Ambassador posthumously to Henri Leder...In the early winter of 2017-18,Xie Yuan,vice-president of the Chinese People’s Association for Friendship with Foreign Countries,visited Belgium to award the title of Friendship Ambassador posthumously to Henri Lederhandler,an old associate of the CPAFFC,and presented the Belgium-China Friendship Award to six other Belgians.展开更多
It’s Mid-Autumn Day today.We don’t have to go to school today.If fact,we have 3 days off.Mid-Autumn Day is a family festival.I can enjoy myself at home with my family.My sister comes home from college.My mother cook...It’s Mid-Autumn Day today.We don’t have to go to school today.If fact,we have 3 days off.Mid-Autumn Day is a family festival.I can enjoy myself at home with my family.My sister comes home from college.My mother cooks a lot of delicious food.My father buys a big Beijing duck.After dinner,we have mooncakes.I like the sweet ones with five nuts in them.My sister likes the ones with eggs.My father and mother like the ones with meat.After dinner.展开更多
Psychology is about people’s actions and their thoughts:the ones they know about as well as the ones they don’t know everything about,like when they’re dreaming.Psychologists-people who study psychology-try to unde...Psychology is about people’s actions and their thoughts:the ones they know about as well as the ones they don’t know everything about,like when they’re dreaming.Psychologists-people who study psychology-try to understand different people and groups to help them feel better.展开更多
Wang Luan is our monitor.Though he is not tall,but he is healthy and strong.He is kind,honest and always ready to helping others.So we made him our monitor.Wang Luan does well in physics and chemistry.Last term,he won...Wang Luan is our monitor.Though he is not tall,but he is healthy and strong.He is kind,honest and always ready to helping others.So we made him our monitor.Wang Luan does well in physics and chemistry.Last term,he won the first prize in the physics and chemistry contest.He is also good at English.In our class,his listening is the best.He is also fond of sports.He is the best football player in our school.展开更多
Origin of Fengshui Woods was studied, 3 representative standpoints (Fengshui doctrines, greening and worship of the god of land) about Fengshui woods were analyzed, and worship of the god of land was believed as a rea...Origin of Fengshui Woods was studied, 3 representative standpoints (Fengshui doctrines, greening and worship of the god of land) about Fengshui woods were analyzed, and worship of the god of land was believed as a reasonable origin view through considering natural and social factors of ancient China, as well as universal mental characteristics of people in the prescience age. To identify advantages and disadvantages of these 3 views, Carl G. Jung' theory of mythological prototype criticism and Sir James George Frazer's anthropological study were borrowed to prove that Fengshui Woods originated from ancient Chinese worship of the god of land, and such worship gradually evolved into practices of planting Fengshui Woods for their propitious signs. On this basis, enlightenment of Fengshui Woods to modern society was disclosed to protect present Fengshui Woods and forest resources.展开更多
The Beijing 2022 Olympic and Paralympic Winter Games, known as the Beijing 2022 Games, took place in Beijing and nearby Zhangjiakou city of Hebei province. The Beijing competition zone undertook all the ice events, th...The Beijing 2022 Olympic and Paralympic Winter Games, known as the Beijing 2022 Games, took place in Beijing and nearby Zhangjiakou city of Hebei province. The Beijing competition zone undertook all the ice events, the Yanqing competition zone was for luge, skeleton, bobsleigh and alpine skiing, and the Zhangjiakou competition zone undertook all the other snow events except the above-mentioned ones.展开更多
Nicolaus Steno:Biography and Original Papers of a 17th Century Scientist,Springer,Heidelberg,2013,739 pp.,ISBN 978-3-642-25078-1,ISBN 978-3-642-25079-8(e-Book),DOI 10.1007/978-3-642-25079-8.Nicolaus Steno(Niels Stense...Nicolaus Steno:Biography and Original Papers of a 17th Century Scientist,Springer,Heidelberg,2013,739 pp.,ISBN 978-3-642-25078-1,ISBN 978-3-642-25079-8(e-Book),DOI 10.1007/978-3-642-25079-8.Nicolaus Steno(Niels Stensen,1638-1686)is best known to historians of the geological sciences for his work that provided the basis of modern geology.He introduced a method for interpreting the relationship between containing bodies and contained ones i.e.‘solids within solids’as a basis for the interpretation of the history of the earth.展开更多
基金the National Natural Science Foundation of China(No.20872056) for financial support.
文摘The cycloaddition of N-acyliminium cations with some deactivated alkenes such as α,β-unsaturate ketones and esters has been investigated. In most cases, the N-acyliminium cations produced from 3-hydroxy-2-arylisoindol-1-ones in the presence of BFa.OEt2 could be reacted with α,β-unsaturated ketones and esters to afford stereoselectively the cycloaddition products 6-acylisoindolo[2,1- a]quinolin-11-ones in moderate to high yields. C 2009 Wei Zhang. Published by Elsevier B.V, on behalf of Chinese Chemical Society. All rights reserved.
文摘The stereoselective synthesis of 2-chloro-4-substituted-phenyl-5,5-dimethyl-1,3,2-dioxaphosphorinan-2-(thi)ones is described. Only single trans-isomers were obtained when 1-substituted-phenyl-2,2-dimethyl-1,3-propanediols (1) reacted with POCl3. But the stereoselectivity of cyclization reaction between (1) and PSCl3 depended greatly upon the reaction condition. The configurational assignments and the ratio of cis-/trans- diastereoisomers of the products were performed on the basis of (HNMR)-H-1, (PNMR)-P-31 and IR spectra and confirmed by X-ray diffraction analyses.
文摘Entry into WTO means that Chinese enterprises, which were deeply influenced by planned economy, will scramble for profits with those world famous transnational companies of strong strength. Facing such competitive situation, how can China cultivate more famous and strong Chinese transnational companies on the international market? This is a question for many economists and enterprisers to make serious research.
文摘one通常可用来替代上文中出现过的可数名词或以可数名词为中心词的整个名词词组,既可指人,也可指物。例如:The speed of the new machine ismuch greater than that of the oldone.There was an old man and ayoung one there.one的复数形式是ones,只能替代复数可数名词,既可指人,也可指物。
文摘Memory enables organisms to encode,store,and retrieve information essential for interacting with and adapting to a dynamic environment.As an internal representation of the external world,memory serves as a crucial bridge between past experiences and future behaviors.However,the brain continuously forms new memories,raising the question of how new memories are integrated without disrupting previously formed ones.
基金ProjectsupportedbytheNationalNaturalScienceFoundationofChina (No .2 0 10 2 0 0 1)
文摘Thirteen new 2 alkylaminoimidazolones (4) were rapidly synthesized by a new solution phase parallel synthetic method, which includes aza Wittig reaction of iminophosphorane (1) with aromatic isocyanate to give carbodi imide (2) and subsequent reaction of 2 with various aliphatic primary amine in a parallel fashion. The products were confirmed by 1H NMR, MS, IR and X ray crystallographic analysis. The unusual selectivity of the cyclization was probably due to the geometry of the guanidine intermediate.
基金Project supported by the National Natural Science Foundation of China.
文摘Using the method of intracellular injection of horseradish peroxidase, the arborizations of several neurones with different functions in the segmental ganglia of the leech Whitmania pigra are investigated. Comparison is made in each kind of neurones in order to verify their typical pattern. Results show that the morphology of the axonal arbors of identified neurones has an accurate similarity within and among the individuals of the leech, and the axonal arborizations of the bilaterally identified neurones in the same ganglion have a stable symmetry. The possible reasons of the formation and its functional significance of the symmetrical nervous system are discussed.
文摘In the early winter of 2017-18,Xie Yuan,vice-president of the Chinese People’s Association for Friendship with Foreign Countries,visited Belgium to award the title of Friendship Ambassador posthumously to Henri Lederhandler,an old associate of the CPAFFC,and presented the Belgium-China Friendship Award to six other Belgians.
文摘It’s Mid-Autumn Day today.We don’t have to go to school today.If fact,we have 3 days off.Mid-Autumn Day is a family festival.I can enjoy myself at home with my family.My sister comes home from college.My mother cooks a lot of delicious food.My father buys a big Beijing duck.After dinner,we have mooncakes.I like the sweet ones with five nuts in them.My sister likes the ones with eggs.My father and mother like the ones with meat.After dinner.
文摘Psychology is about people’s actions and their thoughts:the ones they know about as well as the ones they don’t know everything about,like when they’re dreaming.Psychologists-people who study psychology-try to understand different people and groups to help them feel better.
文摘Wang Luan is our monitor.Though he is not tall,but he is healthy and strong.He is kind,honest and always ready to helping others.So we made him our monitor.Wang Luan does well in physics and chemistry.Last term,he won the first prize in the physics and chemistry contest.He is also good at English.In our class,his listening is the best.He is also fond of sports.He is the best football player in our school.
基金Supported by the Program of Jingdezhen Municipal Joint Association of Social and Scientific Circle (103120401)Staged Fruits of National Natural Science Foundation(41061020)~~
文摘Origin of Fengshui Woods was studied, 3 representative standpoints (Fengshui doctrines, greening and worship of the god of land) about Fengshui woods were analyzed, and worship of the god of land was believed as a reasonable origin view through considering natural and social factors of ancient China, as well as universal mental characteristics of people in the prescience age. To identify advantages and disadvantages of these 3 views, Carl G. Jung' theory of mythological prototype criticism and Sir James George Frazer's anthropological study were borrowed to prove that Fengshui Woods originated from ancient Chinese worship of the god of land, and such worship gradually evolved into practices of planting Fengshui Woods for their propitious signs. On this basis, enlightenment of Fengshui Woods to modern society was disclosed to protect present Fengshui Woods and forest resources.
文摘The Beijing 2022 Olympic and Paralympic Winter Games, known as the Beijing 2022 Games, took place in Beijing and nearby Zhangjiakou city of Hebei province. The Beijing competition zone undertook all the ice events, the Yanqing competition zone was for luge, skeleton, bobsleigh and alpine skiing, and the Zhangjiakou competition zone undertook all the other snow events except the above-mentioned ones.
文摘Nicolaus Steno:Biography and Original Papers of a 17th Century Scientist,Springer,Heidelberg,2013,739 pp.,ISBN 978-3-642-25078-1,ISBN 978-3-642-25079-8(e-Book),DOI 10.1007/978-3-642-25079-8.Nicolaus Steno(Niels Stensen,1638-1686)is best known to historians of the geological sciences for his work that provided the basis of modern geology.He introduced a method for interpreting the relationship between containing bodies and contained ones i.e.‘solids within solids’as a basis for the interpretation of the history of the earth.
