Based on probabilistic fracture mechanics approach, a new concept of material initial fatigue quality （MIFQ） is developed. Then, the relation between S-N curve and crack propagation curve is studied. From the study,...Based on probabilistic fracture mechanics approach, a new concept of material initial fatigue quality （MIFQ） is developed. Then, the relation between S-N curve and crack propagation curve is studied. From the study, a new durability analysis method is presented. In this method, S-N curve is used to determine crack growth rate under constant amplitude loading and evaluate the effects of different factors on durability and then the structural durability is analyzed. The tests and analyses indicate that this method has lower dependence on testing, and higher accuracy, reliability and generality and is convenient for application.展开更多
Objective The nearly parallel N-S-trending rifts in southern Tibet represent the E-W extension of the Tibet Plateau. Most data which constrained the age of the extensional deformation come from isotopic dating of the...Objective The nearly parallel N-S-trending rifts in southern Tibet represent the E-W extension of the Tibet Plateau. Most data which constrained the age of the extensional deformation come from isotopic dating of the dikes probably related to the activity of the nearly N-S faulting and micas from hydrothermal activity and the low- temperature thermochronology of plateau uplift. Previous research shows that there are at least three different ideas about the age of the rifts： （1） older than 16-12 Ma, （2） 14- 10 Ma, and （3） 8-4 Ma （Fig. la）. For the old sedimentary strata represented the beginning of the rifting, the dating of the sediments helps to better define the initial rifting age.展开更多
There is curiosity and awareness throughout the world regarding the role of Information and Communication technologies. This is felt in each and every section of society. Several studies have confirmed and considered ...There is curiosity and awareness throughout the world regarding the role of Information and Communication technologies. This is felt in each and every section of society. Several studies have confirmed and considered information and communication technology’s significance in the field of education. It has not only affected learners but also to the teachers. This paper explores how ICT-based projects affect teachers’ and students’ attitudes. The data was collected through self-prepared attitude scale. It was distributed among the teachers and students of various schools. Two hundred students and one hundred twenty teachers responded to the questionnaire. Analysis was done through the data collected from the teachers as well as from students. The study’s conclusions demonstrated that while there was no significant variation in the attitudes of teachers utilizing different ICT-based programs, there was a substantial difference in the students’ attitude toward learning with different ICT-based programs.展开更多
The Purpose of the Work: The modern mantle and crust have a complex structure and, in addition, contain both thermal and material heterogeneities, as evidenced by the results of seismic and electromagnetic studies. Ch...The Purpose of the Work: The modern mantle and crust have a complex structure and, in addition, contain both thermal and material heterogeneities, as evidenced by the results of seismic and electromagnetic studies. Changes are also reflected by the change in the mineralogical and chemical composition of the matter. This structure was formed for the long geological history of the planet’s development and the process continues at the present time. The system remains unsteady. To understand the evolution of such dynamic structures, information is needed about the initial state of the system, in our case, about the state of the Earth at the final stage of its formation. It can be obtained only by the results of numerical modeling based on the results of the investigation of the evolution of isotope systems. Therefore, the purpose of the work is to identify the features of the formation of mineral deposits in the early crust and mantle. For this, it is necessary to obtain variants of the numerical solution of the problem of the formation of the planet. Solution Methods: An algorithm for solving a non-linear system of differential equations for solving a 3D boundary dynamic problem in the sphere of an increasing radius is developed. The numerical method of “through account” is used in the work. Results: Based on methods for solving boundary value problems for a system of differential equations with the use of new results of mineralogical and isotope studies of the oldest material samples, quantitative variants of the thermal evolution of the Earth, directly determining the formation of early metallogeny, are constructed. It is shown that the random distribution of particles and bodies of a protoplanetary cloud during the accumulation of the planet causes the formation of a random material and temperature composition of the growing crust and mantle, which ensured a special metallogeny of the cratons and their framing, which no longer repeated in the geological history of the planet. A special role in it was played by changes in the gravitational field during the growth of the planet and the angular velocity of the Earth’s rotation. Further Research: It is proposed to extend the results obtained to the conditions for taking into account the dynamics of the double Earth-Moon system.展开更多
The paper studies the propagation of Love waves in a non-homogeneous substratum over an initially stressed heterogeneous half-space. The dispersion equation of phase velocity is derived. The velocities of Love waves a...The paper studies the propagation of Love waves in a non-homogeneous substratum over an initially stressed heterogeneous half-space. The dispersion equation of phase velocity is derived. The velocities of Love waves are calculated numerically as a function of kH and presented in a number of graphs, where k is the wave number, and H is the thickness of the layer. The case of Gibson＇s half-space is also considered. It is observed that the speed of Love waves is finite in the vicinity of the surface of the half-space and vanishes as the depth increases for a particular wave number. It is also observed that an increase in compressive initial stresses causes decreases of Love waves velocity for the same frequency, and the tensile initial stress of small magnitude in the half-space causes increase of the velocity.展开更多
The axon initial segment(AIS)region is crucial for action potential initiation due to the presence of high-density AIS protein voltage-gated sodium channels(Nav).Nav channels comprise several serine residues responsib...The axon initial segment(AIS)region is crucial for action potential initiation due to the presence of high-density AIS protein voltage-gated sodium channels(Nav).Nav channels comprise several serine residues responsible for the recruitment of Nav channels into the structure of AIS through interactions with ankyrin-G(AnkG).In this study,a series of computational experiments are performed to understand the role of AIS proteins casein kinase 2 and AnkG on Nav channel recruitment into the AIS.The computational simulation results using Virtual cell software indicate that Nav channels with all serine sites available for phosphorylation bind to AnkG with strong affinity.At the low initial concentration of AnkG and casein kinase 2,the concentration of Nav channels reduces significantly,suggesting the importance of casein kinase 2 and AnkG in the recruitment of Nav channels.展开更多
The existence,uniqueness,and continuous dependence to the mild solutions of the nonlocal Cauchy problem were proved for a class of semilinear fractional neutral differential equations.The results are obtained by using...The existence,uniqueness,and continuous dependence to the mild solutions of the nonlocal Cauchy problem were proved for a class of semilinear fractional neutral differential equations.The results are obtained by using the Krasnoselskii's fixed point theorem and the theory of resolvent operators for integral equations.展开更多
In this paper, an efficient weight initialization method is proposed using Cauchy’s inequality based on sensitivity analy- sis to improve the convergence speed in single hidden layer feedforward neural networks. The ...In this paper, an efficient weight initialization method is proposed using Cauchy’s inequality based on sensitivity analy- sis to improve the convergence speed in single hidden layer feedforward neural networks. The proposed method ensures that the outputs of hidden neurons are in the active region which increases the rate of convergence. Also the weights are learned by minimizing the sum of squared errors and obtained by solving linear system of equations. The proposed method is simulated on various problems. In all the problems the number of epochs and time required for the proposed method is found to be minimum compared with other weight initialization methods.展开更多
As the chief architect of China’s reform and opening up and a leading personalityof world class,Deng Xiaoping played a historical role in China’s political and e-conomic development in the period of its reform and o...As the chief architect of China’s reform and opening up and a leading personalityof world class,Deng Xiaoping played a historical role in China’s political and e-conomic development in the period of its reform and opening.And so did his globalstrategic thinking,which not only had a decisive bearing on the adjustments,andchanges in China’s foreign strategy and policies,but also made a great展开更多
The present paper contributes in studying the phase velocities of P- and S-waves in a half space subjected to a compressive initial stress and gravity field. The density and acceleration due to gravity vary quadratica...The present paper contributes in studying the phase velocities of P- and S-waves in a half space subjected to a compressive initial stress and gravity field. The density and acceleration due to gravity vary quadratically along the depth. The dispersion equation is derived in a closed form. It is shown that the phase velocities depend not only on the initial stress, gravity, and direction of propagation but also on the inhomogeneity parameter associated with the density and acceleration due to gravity. Various particular cases are obtained, and the results match with the classical results. Numerical investigations on the phase velocities of P- and S-waves against the wave number are made for various sets of values of the material parameters, and the results are illustrated graphically. The graphical user interface model is developed to generalize the effect.展开更多
Background: The Women’s Health Initiative (WHI) published findings in 2002 that changed the perception of the use of hormone replacement therapy (HRT) for the reduction of cardiovascular risks. Menopausal women using...Background: The Women’s Health Initiative (WHI) published findings in 2002 that changed the perception of the use of hormone replacement therapy (HRT) for the reduction of cardiovascular risks. Menopausal women using HRT for the relief of vasomotor symptoms were advised to use the lowest possible dose of HRT over the shortest possible duration. Objective: This study sought to examine patterns of HRT use for the treatment of menopausal symptoms before and after the WHI among women at least 40 years of age. Methods: A retrospective analysis was performed on a total of 1367 women in the pre-WHI group and 6467 women in the post-WHI group using the U.S. General Electric (GE) Centricity electronic medical record database. Menopause diagnosis was assessed using ICD-9 codes. Clinical characteristics and medication use were assessed for women with at least 3 years of enrollment (1 year baseline, 2 years follow-up). Results: The proportion of women in the post-WHI group that initiated HRT was significantly less than that of women in the pre-WHI group (31.3% vs. 56.9%, respectively;p < 0.001). Combination HRT use declined significantly (21.9% pre-WHI cohort vs. 7.2% post- WHI cohort, p < 0.001) among increases in non-HRT use, namely SSRIs (15.2% pre-WHI cohort v. 22.3% post-WHI cohort, p < 0.001) and tranquilizers (9.5% pre-WHI cohort v. 15.8% post-WHI cohort, p < 0.001). Conclusion: The results of the WHI 2002 publication made an impression on the perception of HRT’s role in the relief of menopausal symptoms. Decision-making on the part of women seeking treatment for vasomotor symptoms and women’s health professionals demonstrates that despite HRT precautions, women continue to exhibit a need for HRT use. This study’s findings suggest that women seeking treatment for menopausal symptom relief and women’s health professionals continue to work together to find the appropriate balance between therapy use and adherence to therapy use guidelines.展开更多
Multifunctional organolithium initiator was prepared in cyclohexane solvent. The process started with adding the cyclohexane solution of butadiene to naphthalene-lithium in batches to produce butadiene oligomer dilith...Multifunctional organolithium initiator was prepared in cyclohexane solvent. The process started with adding the cyclohexane solution of butadiene to naphthalene-lithium in batches to produce butadiene oligomer dilithium with 4-8 butadiene repeating units. In the first feeding, the maximum loading of cyclohexane and the minimum concentration of butadiene cyclohexane solution must be controlled under Vcyclohexane 〈 1.33 VTHF and p 〉 40.6cN. Then, SnCl4 was added and eventually the multifunctional organolithium initiator containing Sn atom was synthesized through coupling reaction. Experiment results showed that adding the cyclohexane solution in batches was effective in overcoming some difficulties, such as insolubility of naphthalene-lithium in cyclohexane, low efficiency of naphthalene-lithium in initiating butadiene. In practice, benzene can be replaced by cyclohexane completely, which can not only reduce environmental pollution from benzene, but also overcome the difficulty of solvent recovery caused by similar boiling point between benzene and cyclohexane. Prepared with multifunctional organolithium containing Sn atom as initiator, the star-shaped solution polymerized styrene-butadiene rubber （star S-SBR） with better vulcanization performances, lower rolling resistance and higher wet-skid resistance was obtained.展开更多
The paper analyses the roots of the Belt and Road Initiative as well as China＇s Middle East Energy Policy in an age of great transformation. China＇s rapidly progressed economic growth leading to a dramatic increase ...The paper analyses the roots of the Belt and Road Initiative as well as China＇s Middle East Energy Policy in an age of great transformation. China＇s rapidly progressed economic growth leading to a dramatic increase in China＇s energy demand in recent years. The Middle East countries play a critical role in the international energy markets. Stable relations with the Middle East countries become increasingly important for Chinese energy security, and the continued development. The protection of these relations lies at the core of the Belt and Road Initiative. Within The Belt and Road Initiative, Chinese Middle East energy policy proceeds according to the energy cooperation framework known as ＂1＋2＋3＂, which seeks to build a reliable China-Arab strategic cooperative relationship based on long-term friendship. To avoid over dependence on the energy resources of the Middle East, China will also continue to search for other overseas energy sources and protect transportation channels. Despite risks and challenges associated with energy imports from the Middle East, China has cultivated strong relations with states in the region and will develop these economic ties further in the coming years.展开更多
Nigella sativa, belonging to the Ranunculacea family, is a versatile phytochemical mine bestowed with multi-dimensional medicinal effects. The current study was performed to investigate the chemopreventive efficacy, i...Nigella sativa, belonging to the Ranunculacea family, is a versatile phytochemical mine bestowed with multi-dimensional medicinal effects. The current study was performed to investigate the chemopreventive efficacy, if any, of the ethanolic extract of indigenous Nigella sativa seeds (ENS) and to evaluate its potentials on tumor progression during the initiation and post initiation phases of Dimethylhydrazine-induced colon carcinogenesis in a rat model. ENS treatment during the initiation phase unveiled chemopreventive effect manifested by significant reductions in tumor incidence, multiplicity and tumor volumes. Histopathological findings and modified Duke’s classification of tumors provided evidence that ENS, administered in the initiation phase, is capable of delaying progression, restricting invasion and attenuating aggressiveness of colon tumors. These results imply that ENS may be a promising candidate in the primary prevention of colon cancer. On the contrary, we demonstrated that ENS lacked chemopreventive and tumorigenesis inhibitory effects in the post initiation phase. We speculate that the chemopreventive effect of ENS might be due to the synergistic actions of various constituents present in the extract. However, extensive studies are warranted and more efforts need to be dedicated to fractionate, analyze and to further appraise the anticancer effect of ENS before any definitive conclusions can be drawn.展开更多
China＇s international energy cooperation and energy security are important parts of The Belt and Road initiatives. China and the countries along the Belt and Road continue to promote cooperation, actively use the exi...China＇s international energy cooperation and energy security are important parts of The Belt and Road initiatives. China and the countries along the Belt and Road continue to promote cooperation, actively use the existing bilateral and multilateral cooperation mechanisms to promote the regional and inter-regional energy cooperation. Countries along the Belt and Road are rich in oil and gas resources; their demand on the diversification of export meet with the diversification demand on imports of consumption countries; and their oil refining and chemical technology as well as construction capacity is weak, which provides a lot of new opportunities in cooperation for Chinese enterprises. However, the energy cooperation of Chinese enterprises are also facing some challenges in the complex environment of energy cooperation, the interference of big powers, non-traditional security threats, and energy policy factors. Finally, the paper puts forward the strategic thinking of China＇s international energy cooperation under the new situation.展开更多
A comparative study is made on the efficiencies of three initiators of Fe^(2+)-H_2O_2, K_2S_2O_8 and KMnO_4 in the grafting of acrylamide onto starch. Of the three initiators the best one is KMnO_4. Moreover, the kine...A comparative study is made on the efficiencies of three initiators of Fe^(2+)-H_2O_2, K_2S_2O_8 and KMnO_4 in the grafting of acrylamide onto starch. Of the three initiators the best one is KMnO_4. Moreover, the kinetic equation is also studied.展开更多
Miguel Street is a collection of linked short stories by the Nobel Laureate V.S.Naipaul.To interpret the initiation theme inMiguel Street,this paper uses Rui Yuping’s theory structure to analyze the three major parts...Miguel Street is a collection of linked short stories by the Nobel Laureate V.S.Naipaul.To interpret the initiation theme inMiguel Street,this paper uses Rui Yuping’s theory structure to analyze the three major parts of the growing progress of the narra tor“I”.This paper also uses postcolonial criticism to interpret the confusing situation which“I”was in and the narrative strategy in this novel.The conclusion is that the only solution for“I”and even the whole country is to escape from the confusing situation.展开更多
基金National Natural Science Foundation of China (60472118) High-tech Research Project of Jiangsu Province (BG2004008)
文摘Based on probabilistic fracture mechanics approach, a new concept of material initial fatigue quality （MIFQ） is developed. Then, the relation between S-N curve and crack propagation curve is studied. From the study, a new durability analysis method is presented. In this method, S-N curve is used to determine crack growth rate under constant amplitude loading and evaluate the effects of different factors on durability and then the structural durability is analyzed. The tests and analyses indicate that this method has lower dependence on testing, and higher accuracy, reliability and generality and is convenient for application.
基金supported by the National Natural Science Foundation of China(grant No.41571013)Project of China Geological Survey(grant No.12120114002101)
文摘Objective The nearly parallel N-S-trending rifts in southern Tibet represent the E-W extension of the Tibet Plateau. Most data which constrained the age of the extensional deformation come from isotopic dating of the dikes probably related to the activity of the nearly N-S faulting and micas from hydrothermal activity and the low- temperature thermochronology of plateau uplift. Previous research shows that there are at least three different ideas about the age of the rifts： （1） older than 16-12 Ma, （2） 14- 10 Ma, and （3） 8-4 Ma （Fig. la）. For the old sedimentary strata represented the beginning of the rifting, the dating of the sediments helps to better define the initial rifting age.
文摘There is curiosity and awareness throughout the world regarding the role of Information and Communication technologies. This is felt in each and every section of society. Several studies have confirmed and considered information and communication technology’s significance in the field of education. It has not only affected learners but also to the teachers. This paper explores how ICT-based projects affect teachers’ and students’ attitudes. The data was collected through self-prepared attitude scale. It was distributed among the teachers and students of various schools. Two hundred students and one hundred twenty teachers responded to the questionnaire. Analysis was done through the data collected from the teachers as well as from students. The study’s conclusions demonstrated that while there was no significant variation in the attitudes of teachers utilizing different ICT-based programs, there was a substantial difference in the students’ attitude toward learning with different ICT-based programs.
文摘The Purpose of the Work: The modern mantle and crust have a complex structure and, in addition, contain both thermal and material heterogeneities, as evidenced by the results of seismic and electromagnetic studies. Changes are also reflected by the change in the mineralogical and chemical composition of the matter. This structure was formed for the long geological history of the planet’s development and the process continues at the present time. The system remains unsteady. To understand the evolution of such dynamic structures, information is needed about the initial state of the system, in our case, about the state of the Earth at the final stage of its formation. It can be obtained only by the results of numerical modeling based on the results of the investigation of the evolution of isotope systems. Therefore, the purpose of the work is to identify the features of the formation of mineral deposits in the early crust and mantle. For this, it is necessary to obtain variants of the numerical solution of the problem of the formation of the planet. Solution Methods: An algorithm for solving a non-linear system of differential equations for solving a 3D boundary dynamic problem in the sphere of an increasing radius is developed. The numerical method of “through account” is used in the work. Results: Based on methods for solving boundary value problems for a system of differential equations with the use of new results of mineralogical and isotope studies of the oldest material samples, quantitative variants of the thermal evolution of the Earth, directly determining the formation of early metallogeny, are constructed. It is shown that the random distribution of particles and bodies of a protoplanetary cloud during the accumulation of the planet causes the formation of a random material and temperature composition of the growing crust and mantle, which ensured a special metallogeny of the cratons and their framing, which no longer repeated in the geological history of the planet. A special role in it was played by changes in the gravitational field during the growth of the planet and the angular velocity of the Earth’s rotation. Further Research: It is proposed to extend the results obtained to the conditions for taking into account the dynamics of the double Earth-Moon system.
文摘The paper studies the propagation of Love waves in a non-homogeneous substratum over an initially stressed heterogeneous half-space. The dispersion equation of phase velocity is derived. The velocities of Love waves are calculated numerically as a function of kH and presented in a number of graphs, where k is the wave number, and H is the thickness of the layer. The case of Gibson＇s half-space is also considered. It is observed that the speed of Love waves is finite in the vicinity of the surface of the half-space and vanishes as the depth increases for a particular wave number. It is also observed that an increase in compressive initial stresses causes decreases of Love waves velocity for the same frequency, and the tensile initial stress of small magnitude in the half-space causes increase of the velocity.
文摘The axon initial segment(AIS)region is crucial for action potential initiation due to the presence of high-density AIS protein voltage-gated sodium channels(Nav).Nav channels comprise several serine residues responsible for the recruitment of Nav channels into the structure of AIS through interactions with ankyrin-G(AnkG).In this study,a series of computational experiments are performed to understand the role of AIS proteins casein kinase 2 and AnkG on Nav channel recruitment into the AIS.The computational simulation results using Virtual cell software indicate that Nav channels with all serine sites available for phosphorylation bind to AnkG with strong affinity.At the low initial concentration of AnkG and casein kinase 2,the concentration of Nav channels reduces significantly,suggesting the importance of casein kinase 2 and AnkG in the recruitment of Nav channels.
文摘The existence,uniqueness,and continuous dependence to the mild solutions of the nonlocal Cauchy problem were proved for a class of semilinear fractional neutral differential equations.The results are obtained by using the Krasnoselskii's fixed point theorem and the theory of resolvent operators for integral equations.
文摘In this paper, an efficient weight initialization method is proposed using Cauchy’s inequality based on sensitivity analy- sis to improve the convergence speed in single hidden layer feedforward neural networks. The proposed method ensures that the outputs of hidden neurons are in the active region which increases the rate of convergence. Also the weights are learned by minimizing the sum of squared errors and obtained by solving linear system of equations. The proposed method is simulated on various problems. In all the problems the number of epochs and time required for the proposed method is found to be minimum compared with other weight initialization methods.
文摘As the chief architect of China’s reform and opening up and a leading personalityof world class,Deng Xiaoping played a historical role in China’s political and e-conomic development in the period of its reform and opening.And so did his globalstrategic thinking,which not only had a decisive bearing on the adjustments,andchanges in China’s foreign strategy and policies,but also made a great
基金supported by the Research Fellow of Indian School of Mines in Dhanbad (No. 2010DR0016)
文摘The present paper contributes in studying the phase velocities of P- and S-waves in a half space subjected to a compressive initial stress and gravity field. The density and acceleration due to gravity vary quadratically along the depth. The dispersion equation is derived in a closed form. It is shown that the phase velocities depend not only on the initial stress, gravity, and direction of propagation but also on the inhomogeneity parameter associated with the density and acceleration due to gravity. Various particular cases are obtained, and the results match with the classical results. Numerical investigations on the phase velocities of P- and S-waves against the wave number are made for various sets of values of the material parameters, and the results are illustrated graphically. The graphical user interface model is developed to generalize the effect.
文摘Background: The Women’s Health Initiative (WHI) published findings in 2002 that changed the perception of the use of hormone replacement therapy (HRT) for the reduction of cardiovascular risks. Menopausal women using HRT for the relief of vasomotor symptoms were advised to use the lowest possible dose of HRT over the shortest possible duration. Objective: This study sought to examine patterns of HRT use for the treatment of menopausal symptoms before and after the WHI among women at least 40 years of age. Methods: A retrospective analysis was performed on a total of 1367 women in the pre-WHI group and 6467 women in the post-WHI group using the U.S. General Electric (GE) Centricity electronic medical record database. Menopause diagnosis was assessed using ICD-9 codes. Clinical characteristics and medication use were assessed for women with at least 3 years of enrollment (1 year baseline, 2 years follow-up). Results: The proportion of women in the post-WHI group that initiated HRT was significantly less than that of women in the pre-WHI group (31.3% vs. 56.9%, respectively;p < 0.001). Combination HRT use declined significantly (21.9% pre-WHI cohort vs. 7.2% post- WHI cohort, p < 0.001) among increases in non-HRT use, namely SSRIs (15.2% pre-WHI cohort v. 22.3% post-WHI cohort, p < 0.001) and tranquilizers (9.5% pre-WHI cohort v. 15.8% post-WHI cohort, p < 0.001). Conclusion: The results of the WHI 2002 publication made an impression on the perception of HRT’s role in the relief of menopausal symptoms. Decision-making on the part of women seeking treatment for vasomotor symptoms and women’s health professionals demonstrates that despite HRT precautions, women continue to exhibit a need for HRT use. This study’s findings suggest that women seeking treatment for menopausal symptom relief and women’s health professionals continue to work together to find the appropriate balance between therapy use and adherence to therapy use guidelines.
基金supported by the "Tenth Five" National Scientific and Technological Projects (No.2004BA310A41 )
文摘Multifunctional organolithium initiator was prepared in cyclohexane solvent. The process started with adding the cyclohexane solution of butadiene to naphthalene-lithium in batches to produce butadiene oligomer dilithium with 4-8 butadiene repeating units. In the first feeding, the maximum loading of cyclohexane and the minimum concentration of butadiene cyclohexane solution must be controlled under Vcyclohexane 〈 1.33 VTHF and p 〉 40.6cN. Then, SnCl4 was added and eventually the multifunctional organolithium initiator containing Sn atom was synthesized through coupling reaction. Experiment results showed that adding the cyclohexane solution in batches was effective in overcoming some difficulties, such as insolubility of naphthalene-lithium in cyclohexane, low efficiency of naphthalene-lithium in initiating butadiene. In practice, benzene can be replaced by cyclohexane completely, which can not only reduce environmental pollution from benzene, but also overcome the difficulty of solvent recovery caused by similar boiling point between benzene and cyclohexane. Prepared with multifunctional organolithium containing Sn atom as initiator, the star-shaped solution polymerized styrene-butadiene rubber （star S-SBR） with better vulcanization performances, lower rolling resistance and higher wet-skid resistance was obtained.
文摘The paper analyses the roots of the Belt and Road Initiative as well as China＇s Middle East Energy Policy in an age of great transformation. China＇s rapidly progressed economic growth leading to a dramatic increase in China＇s energy demand in recent years. The Middle East countries play a critical role in the international energy markets. Stable relations with the Middle East countries become increasingly important for Chinese energy security, and the continued development. The protection of these relations lies at the core of the Belt and Road Initiative. Within The Belt and Road Initiative, Chinese Middle East energy policy proceeds according to the energy cooperation framework known as ＂1＋2＋3＂, which seeks to build a reliable China-Arab strategic cooperative relationship based on long-term friendship. To avoid over dependence on the energy resources of the Middle East, China will also continue to search for other overseas energy sources and protect transportation channels. Despite risks and challenges associated with energy imports from the Middle East, China has cultivated strong relations with states in the region and will develop these economic ties further in the coming years.
文摘Nigella sativa, belonging to the Ranunculacea family, is a versatile phytochemical mine bestowed with multi-dimensional medicinal effects. The current study was performed to investigate the chemopreventive efficacy, if any, of the ethanolic extract of indigenous Nigella sativa seeds (ENS) and to evaluate its potentials on tumor progression during the initiation and post initiation phases of Dimethylhydrazine-induced colon carcinogenesis in a rat model. ENS treatment during the initiation phase unveiled chemopreventive effect manifested by significant reductions in tumor incidence, multiplicity and tumor volumes. Histopathological findings and modified Duke’s classification of tumors provided evidence that ENS, administered in the initiation phase, is capable of delaying progression, restricting invasion and attenuating aggressiveness of colon tumors. These results imply that ENS may be a promising candidate in the primary prevention of colon cancer. On the contrary, we demonstrated that ENS lacked chemopreventive and tumorigenesis inhibitory effects in the post initiation phase. We speculate that the chemopreventive effect of ENS might be due to the synergistic actions of various constituents present in the extract. However, extensive studies are warranted and more efforts need to be dedicated to fractionate, analyze and to further appraise the anticancer effect of ENS before any definitive conclusions can be drawn.
文摘China＇s international energy cooperation and energy security are important parts of The Belt and Road initiatives. China and the countries along the Belt and Road continue to promote cooperation, actively use the existing bilateral and multilateral cooperation mechanisms to promote the regional and inter-regional energy cooperation. Countries along the Belt and Road are rich in oil and gas resources; their demand on the diversification of export meet with the diversification demand on imports of consumption countries; and their oil refining and chemical technology as well as construction capacity is weak, which provides a lot of new opportunities in cooperation for Chinese enterprises. However, the energy cooperation of Chinese enterprises are also facing some challenges in the complex environment of energy cooperation, the interference of big powers, non-traditional security threats, and energy policy factors. Finally, the paper puts forward the strategic thinking of China＇s international energy cooperation under the new situation.
文摘A comparative study is made on the efficiencies of three initiators of Fe^(2+)-H_2O_2, K_2S_2O_8 and KMnO_4 in the grafting of acrylamide onto starch. Of the three initiators the best one is KMnO_4. Moreover, the kinetic equation is also studied.
文摘Miguel Street is a collection of linked short stories by the Nobel Laureate V.S.Naipaul.To interpret the initiation theme inMiguel Street,this paper uses Rui Yuping’s theory structure to analyze the three major parts of the growing progress of the narra tor“I”.This paper also uses postcolonial criticism to interpret the confusing situation which“I”was in and the narrative strategy in this novel.The conclusion is that the only solution for“I”and even the whole country is to escape from the confusing situation.
