The study profiles and explains the significant changes that have taken place in China's spatial development patterns since the inception of its economic reform and opening two decades ago. Principal component an...The study profiles and explains the significant changes that have taken place in China's spatial development patterns since the inception of its economic reform and opening two decades ago. Principal component analysis is used to delineate spatial patterns. The analyses show that prior to the reform China's spatial development pattern was characterized by the dominance of the three municipalities and the Northeast, as well as by both the coast-interior and the north-south disparities. Northern provinces were generally more industrialized and economically powerful than the southern ones. After two decades of reform, regional development has become multi-centered with South China, the Yangtze Delta and the Beijing-Tianjin area being the three most important regions of the country. The coastal provinces as a whole rose to prominence on China's economic map while the Northeast has diminished its clout. The coast-interior gap not only remains but may have widened. The north-south disparity also still exists but there has been a role reversal with the south now in the lead position. Virtually all inland provinces now find themselves at or near the low end of the development spectrum. We argue that the major reason for the recent shifts in Chinese space economy is the spatially differentiated economic growth resulted from the reform and open door policy and from the new, uneven development strategy adopted by the Chinese government. The paper discusses four specific factors that have reshaped China's spatial development patterns.展开更多
This paper aimed to highlight the effects of conflict in Mongolia on trade policy and openness, by estimating the trade flows with neighbor countries （China and Russia）. Fourteen years＇ （2000-2013） data of Mongol...This paper aimed to highlight the effects of conflict in Mongolia on trade policy and openness, by estimating the trade flows with neighbor countries （China and Russia）. Fourteen years＇ （2000-2013） data of Mongolian imports and exports were collected and gone through principal component analysis （PCA） and empirical analysis for grouping various trades with China and Russia. The empirical analysis identified the determining factors of Mongolian trade flow and openness with China and Russia. Empirical analysis evidenced that Mongolian trade and openness policy raised bilateral trade between China and Russia, leaving a great influence on economic size. Two main questions represented as empirically tested by each sample country. How did Mongolian trade policy and openness influence trade flows between China and Russia and economic growth of Mongolia？ Did Mongolian trade policy and the bilateral trade with China and Russia increase on trade openness？ Finally, the study focused on the forecasts from 2016 to 2018 to examine Mongolian trade flows with China and Russia using ordinary least squares method and autoregressive-moving-average （ARMA） model. China-Mongolia-Russia trade flows will continue to dominate during the forecasted period. As shown by the structure of export and import, goods with China and Russia influenced the mutual trade amount. Moreover, China and Russia traded to continue with Mongolia for goods in long run. Trade policy and openness, the major contributor in Mongolian economy, are significantly playing roles in trade and economy.展开更多
Since ushering in the 1990s, Hengshui City has been taking advantage of its excellent geographical position to develop its foreign-oriented economy, with good results. Take last year for example, the city signed contr...Since ushering in the 1990s, Hengshui City has been taking advantage of its excellent geographical position to develop its foreign-oriented economy, with good results. Take last year for example, the city signed contracts for altogether 28 foreign-invested projects, with a total capital of US$19.37 million and contractual capital of US$ 5.73 million, 14 completed and constructing foreign-invested projects, of which six have been put into operation. The infrastructure is being further improved in the Hi-tech Industrial Park which includes 49 projects of a total investment of RMB 180 million. The Hengshui Lake Economic and Technology展开更多
This paper develops a two-regional growth model with amenity, capital accumulation and regional public goods with public goods and fiscal policies. The economy consists of two regions and each region consists of the i...This paper develops a two-regional growth model with amenity, capital accumulation and regional public goods with public goods and fiscal policies. The economy consists of two regions and each region consists of the industrial sector and public sector. The industrial sector provides goods in perfectly competitive markets. The public sector, which is financed by the regional government’s tax incomes, supplies regional public goods. The public goods affect both firms and households. We show how to find equilibrium values of the dynamic system and simulate model. Then, we carry out comparative statics analysis with regard to parameter changes in tax rates, congestion and amenity. Our comparative statics analysis provides some important insights. For instance, a main difference between the effects of increasing the two regions’ tax rates on the output is that as the technologically advanced region’s (the other region’s) tax rate on the industrial sector is increased, the national industrial output, national capital employed by the economy, and the national wealth are increased (reduced). In the region which increases the tax rate, the wage rate, consumption and wealth per capita, output per labor force, the population, and land rent are increased, and the corresponding variables in the other region are reduced.展开更多
随着大学英语教学改革的深入,大学英语教师应不断改进大学英语课堂教学方法。经过多年的大学英语教学实践,探索、总结出"5-Open"方法,即:Open your eyes(睁开眼睛看);Open your ears(打开耳朵听);Open your hear(t敞开心扉去...随着大学英语教学改革的深入,大学英语教师应不断改进大学英语课堂教学方法。经过多年的大学英语教学实践,探索、总结出"5-Open"方法,即:Open your eyes(睁开眼睛看);Open your ears(打开耳朵听);Open your hear(t敞开心扉去感受);Open yourmind(放飞思想去创造);Open your mouth(张开嘴巴说)。"5-Open"诠释了教师和学生在教学活动中的角色及双向、动态、互补作用,是激发学生语言学习动机、培养学生全面健康发展、提高大学英语教学效果有益的探索。展开更多
Steel 20Mn23AlV is a type of high aluminum steel with a very low ladle free-opening rate. The aluminum composition of 20Mn23AlV ranges from 1.6% to 2.45% ,which is significantly higher than other types of steel. Accor...Steel 20Mn23AlV is a type of high aluminum steel with a very low ladle free-opening rate. The aluminum composition of 20Mn23AlV ranges from 1.6% to 2.45% ,which is significantly higher than other types of steel. According to the real condition of 40 t ladle in steel-making plant of Baosteel Special Steel Company, previous works show that the key factors affecting the ladle free-opening rate of high aluminum steel in continuous casting are：sand material, accessories baking, ladle nozzle cleaning, the process and amount of adding sand, and the rate of argon stirring during refining. Therefore, improving the ladle filler sand quality, baking all of the raw materials, controlling the addition of ladle filler sand, cleaning the ladle nozzle, and optimizing argon stirring during the refining process can resolve the problem of a low ladle free-opening rate of high aluminum steel caused by the long ladle time of liquid steel.展开更多
In 2023,Baishideng Publishing Group(Baishideng)routinely published 47 openaccess journals,including 46 English-language journals and 1 Chinese-language journal.Our successes were accomplished through the collective de...In 2023,Baishideng Publishing Group(Baishideng)routinely published 47 openaccess journals,including 46 English-language journals and 1 Chinese-language journal.Our successes were accomplished through the collective dedicated efforts of Baishideng staffs,Editorial Board Members,and Peer Reviewers.Among these 47 Baishideng journals,7 are included in the Science Citation Index Expanded(SCIE)and 6 in the Emerging Sources Citation Index(ESCI).With the support of Baishideng authors,company staffs,Editorial Board Members,and Peer Reviewers,the publication work of 2023 is about to be successfully completed.This editorial summarizes the 2023 activities and accomplishments of the 13 SCIEand ESCI-indexed Baishideng journals,outlines the Baishideng publishing policy changes and additions made this year,and highlights the unique advantages of Baishideng journals.展开更多
The Xuyi Schmidt Telescope Photometric Survey of the Galactic Anti-center（XSTPS-GAC）is a photometric sky survey that covers nearly 6000 deg^2 towards the Galactic Anti-center（GAC） in the g,r,i bands. Half of its s...The Xuyi Schmidt Telescope Photometric Survey of the Galactic Anti-center（XSTPS-GAC）is a photometric sky survey that covers nearly 6000 deg^2 towards the Galactic Anti-center（GAC） in the g,r,i bands. Half of its survey field is located on the Galactic Anti-center disk,which makes XSTPSGAC highly suitable to search for new open clusters in the GAC region. In this paper,we report new open cluster candidates discovered in this survey,as well as properties of these open cluster candidates,such as age,distance and reddening,derived by isochrone fitting in the color-magnitude diagram（CMD）.These open cluster candidates are stellar density peaks detected in the star density maps by applying the method from Koposov et al. Each candidate is inspected in terms of its true color image composed from three XSTPS-GAC band images. Then its CMD is checked,in order to identify whether the central region stars have a clear isochrone-like trend differing from background stars. The parameters derived from isochrone fitting for these candidates are mainly based on three band photometry of XSTPS-GAC.Moreover,when these new candidates are able to be seen clearly in 2 MASS data,their parameters are also derived based on the 2 MASS（J-H,J） CMD. There are a total of 320 known open clusters rediscovered and 24 new open cluster candidates discovered in this work. Furthermore,the parameters of these new candidates,as well as another 11 previously known open clusters,are properly determined for the first time.展开更多
It has been found that there are marked errors in the value of valid opening size of heat-bonded nonwoven fabrics between theoretical calculations and engineering measurements. A new modified theoretical model is adva...It has been found that there are marked errors in the value of valid opening size of heat-bonded nonwoven fabrics between theoretical calculations and engineering measurements. A new modified theoretical model is advanced in this paper. The equivalent diameter of the pore of a fibre web is used to calculate the valid opening size instead of the maximum diameter of inscribed circle used, because the fibres in practical fibre webs are flexible elastomers with definite diameters and the pore of fibre web may produce deformation in screening teat and engineering usage. The results show that the theoretical calculations coincide well with the engineering measurements. This method offers a theoretical basis for computer simulation to the performance of filters of heatbonded nonwoven fabrics.展开更多
When implementing open access, policy pioneers and flagship institutions alike have faced considerable challenges in meeting their own aims and achieving a recognized success. Legitimate authority, sufficient resource...When implementing open access, policy pioneers and flagship institutions alike have faced considerable challenges in meeting their own aims and achieving a recognized success. Legitimate authority, sufficient resources and the right timing are crucial, but the professionals charged with implementing policy still need several years to accomplish significant progress. This study defines a methodological standard for evaluating the first generation of open access policies. Evaluating implementation establishes evidence, enables reflection, and may foster the emergence of a second generation of open access policies.While the study is based on a small number of cases, these case studies cover most of the pioneer institutions, present the most significant issues and offer an international overview.Each case is reconstructed individually on the basis of public documents and background information, and supported by interviews with professionals responsible for open access implementation. This article presents the highlights from each case study. The results are utilized to indicate how a second generation of policies might define open access as a key component of digital research infrastructures that provide inputs and outputs for research,teaching and learning in real time.展开更多
This paper presents a preliminary test of the k-th nearest neighbor distance （KNND） method for detecting nearby open clusters based on Gaia-DR1. We select 38 386 nearby stars （〈 100 pc） from the Gaia-DR1 catalog,...This paper presents a preliminary test of the k-th nearest neighbor distance （KNND） method for detecting nearby open clusters based on Gaia-DR1. We select 38 386 nearby stars （〈 100 pc） from the Gaia-DR1 catalog, and then use the KNND method to detect overdense regions in three-dimensional space. We find two overdense regions （the Hyades and Coma Berenices （Coma Ber） open clusters）, and obtain 57 reliable cluster members. Based on these cluster members, the distances to the Hyades and Coma Ber clusters are determined to be 46.0±0.2 and 83.5±0.3 pc, respectively. Our results demonstrate that the KNND method can be used to detect open clusters based on a large volume of astrometry data.展开更多
Firstly, this paper theoretically proves that with the development of open economy the effect of monetary policy will become poor. Secondly, the paper empirically analyzes the impact of open economy on our monetary po...Firstly, this paper theoretically proves that with the development of open economy the effect of monetary policy will become poor. Secondly, the paper empirically analyzes the impact of open economy on our monetary policy. We conclude that there no longer exists long stable relationship between money supply and economic growth. Finally, in four aspects the paper concretely points out that with the open of economy great changes will take place in the implementation of our monetary policy.展开更多
It has been our consistent policy to expand the opening policy, while using foreign capital reasonably and effectively. Our experience of economic development since China’s economic reform and opening to the outside ...It has been our consistent policy to expand the opening policy, while using foreign capital reasonably and effectively. Our experience of economic development since China’s economic reform and opening to the outside world 20 years ago has shown that implementing the opening policy, participation in the international division of labour and exchange, the use of both domestic and international markets and resources, and the introduction of a foreign展开更多
China has undergone the three major stages in its development of foreign-invested enterprise: exploratory development, accelerated development and innovative development. This harnessing of foreign investment has resu...China has undergone the three major stages in its development of foreign-invested enterprise: exploratory development, accelerated development and innovative development. This harnessing of foreign investment has resulted in tremendous success for China, including making up for the funds shortage for economic construction, promoting corporate technological progress and management expertise, easing employment pressure, increasing fiscal revenue and boosting trade. At the same time, there have been problems, including questions of economic security, environment and energy issues, unequal competition and problems with the management of foreign-invested enterprises. To promote the development of foreign-invested enterprises in both a healthy and rapid fashion, China should look toward "maintaining policy continuity, promoting the forward-looking nature of policy, strengthening policy guidance and highlighting policy innovativeness."展开更多
Open clusters are the basic building blocks that serve as a laboratory for the study of young stellar populations in the Milky Way.Variable stars in open clusters provide a unique way to accurately probe the internal ...Open clusters are the basic building blocks that serve as a laboratory for the study of young stellar populations in the Milky Way.Variable stars in open clusters provide a unique way to accurately probe the internal structure,temporal and dynamical evolutionary stages of individual stars and the host cluster.The most powerful tool for such studies is time-domain photometric observations.This paper follows the route of our previous work,concentrating on a photometric search for variable stars in NGC 884.The target cluster is the companion of NGC869,forming the well-known double cluster system that is gravitationally bound.From the observation run in 2016 November,a total of 9247 B-band CCD images and 8218Ⅴ-band CCD images were obtained.We detected a total of 15 stars with variability in visual brightness,including five Be stars,three eclipsing binaries,and seven of unknown types.Two new variable stars were discovered in this work.We also compared the variable star content of NGC 884 with its companion NGC 869.展开更多
文摘The study profiles and explains the significant changes that have taken place in China's spatial development patterns since the inception of its economic reform and opening two decades ago. Principal component analysis is used to delineate spatial patterns. The analyses show that prior to the reform China's spatial development pattern was characterized by the dominance of the three municipalities and the Northeast, as well as by both the coast-interior and the north-south disparities. Northern provinces were generally more industrialized and economically powerful than the southern ones. After two decades of reform, regional development has become multi-centered with South China, the Yangtze Delta and the Beijing-Tianjin area being the three most important regions of the country. The coastal provinces as a whole rose to prominence on China's economic map while the Northeast has diminished its clout. The coast-interior gap not only remains but may have widened. The north-south disparity also still exists but there has been a role reversal with the south now in the lead position. Virtually all inland provinces now find themselves at or near the low end of the development spectrum. We argue that the major reason for the recent shifts in Chinese space economy is the spatially differentiated economic growth resulted from the reform and open door policy and from the new, uneven development strategy adopted by the Chinese government. The paper discusses four specific factors that have reshaped China's spatial development patterns.
文摘This paper aimed to highlight the effects of conflict in Mongolia on trade policy and openness, by estimating the trade flows with neighbor countries （China and Russia）. Fourteen years＇ （2000-2013） data of Mongolian imports and exports were collected and gone through principal component analysis （PCA） and empirical analysis for grouping various trades with China and Russia. The empirical analysis identified the determining factors of Mongolian trade flow and openness with China and Russia. Empirical analysis evidenced that Mongolian trade and openness policy raised bilateral trade between China and Russia, leaving a great influence on economic size. Two main questions represented as empirically tested by each sample country. How did Mongolian trade policy and openness influence trade flows between China and Russia and economic growth of Mongolia？ Did Mongolian trade policy and the bilateral trade with China and Russia increase on trade openness？ Finally, the study focused on the forecasts from 2016 to 2018 to examine Mongolian trade flows with China and Russia using ordinary least squares method and autoregressive-moving-average （ARMA） model. China-Mongolia-Russia trade flows will continue to dominate during the forecasted period. As shown by the structure of export and import, goods with China and Russia influenced the mutual trade amount. Moreover, China and Russia traded to continue with Mongolia for goods in long run. Trade policy and openness, the major contributor in Mongolian economy, are significantly playing roles in trade and economy.
文摘Since ushering in the 1990s, Hengshui City has been taking advantage of its excellent geographical position to develop its foreign-oriented economy, with good results. Take last year for example, the city signed contracts for altogether 28 foreign-invested projects, with a total capital of US$19.37 million and contractual capital of US$ 5.73 million, 14 completed and constructing foreign-invested projects, of which six have been put into operation. The infrastructure is being further improved in the Hi-tech Industrial Park which includes 49 projects of a total investment of RMB 180 million. The Hengshui Lake Economic and Technology
文摘This paper develops a two-regional growth model with amenity, capital accumulation and regional public goods with public goods and fiscal policies. The economy consists of two regions and each region consists of the industrial sector and public sector. The industrial sector provides goods in perfectly competitive markets. The public sector, which is financed by the regional government’s tax incomes, supplies regional public goods. The public goods affect both firms and households. We show how to find equilibrium values of the dynamic system and simulate model. Then, we carry out comparative statics analysis with regard to parameter changes in tax rates, congestion and amenity. Our comparative statics analysis provides some important insights. For instance, a main difference between the effects of increasing the two regions’ tax rates on the output is that as the technologically advanced region’s (the other region’s) tax rate on the industrial sector is increased, the national industrial output, national capital employed by the economy, and the national wealth are increased (reduced). In the region which increases the tax rate, the wage rate, consumption and wealth per capita, output per labor force, the population, and land rent are increased, and the corresponding variables in the other region are reduced.
文摘随着大学英语教学改革的深入,大学英语教师应不断改进大学英语课堂教学方法。经过多年的大学英语教学实践,探索、总结出"5-Open"方法,即:Open your eyes(睁开眼睛看);Open your ears(打开耳朵听);Open your hear(t敞开心扉去感受);Open yourmind(放飞思想去创造);Open your mouth(张开嘴巴说)。"5-Open"诠释了教师和学生在教学活动中的角色及双向、动态、互补作用,是激发学生语言学习动机、培养学生全面健康发展、提高大学英语教学效果有益的探索。
文摘Steel 20Mn23AlV is a type of high aluminum steel with a very low ladle free-opening rate. The aluminum composition of 20Mn23AlV ranges from 1.6% to 2.45% ,which is significantly higher than other types of steel. According to the real condition of 40 t ladle in steel-making plant of Baosteel Special Steel Company, previous works show that the key factors affecting the ladle free-opening rate of high aluminum steel in continuous casting are：sand material, accessories baking, ladle nozzle cleaning, the process and amount of adding sand, and the rate of argon stirring during refining. Therefore, improving the ladle filler sand quality, baking all of the raw materials, controlling the addition of ladle filler sand, cleaning the ladle nozzle, and optimizing argon stirring during the refining process can resolve the problem of a low ladle free-opening rate of high aluminum steel caused by the long ladle time of liquid steel.
文摘In 2023,Baishideng Publishing Group(Baishideng)routinely published 47 openaccess journals,including 46 English-language journals and 1 Chinese-language journal.Our successes were accomplished through the collective dedicated efforts of Baishideng staffs,Editorial Board Members,and Peer Reviewers.Among these 47 Baishideng journals,7 are included in the Science Citation Index Expanded(SCIE)and 6 in the Emerging Sources Citation Index(ESCI).With the support of Baishideng authors,company staffs,Editorial Board Members,and Peer Reviewers,the publication work of 2023 is about to be successfully completed.This editorial summarizes the 2023 activities and accomplishments of the 13 SCIEand ESCI-indexed Baishideng journals,outlines the Baishideng publishing policy changes and additions made this year,and highlights the unique advantages of Baishideng journals.
基金supported by the National Natural Science Foundation of China (NSFC,Grant Nos.11473001,11233004,11078006,11633009 and 11273067)the Minor Planet Foundation of Purple Mountain Observatory+2 种基金supported by the National Key Basic Research Program of China (2014CB845700)the China Postdoctoral Science Foundation (Grant No.2017M610695)supported by Special Funding for Advanced Users,budgeted and administrated by the Center for Astronomical Mega-Science,Chinese Academy of Sciences
文摘The Xuyi Schmidt Telescope Photometric Survey of the Galactic Anti-center（XSTPS-GAC）is a photometric sky survey that covers nearly 6000 deg^2 towards the Galactic Anti-center（GAC） in the g,r,i bands. Half of its survey field is located on the Galactic Anti-center disk,which makes XSTPSGAC highly suitable to search for new open clusters in the GAC region. In this paper,we report new open cluster candidates discovered in this survey,as well as properties of these open cluster candidates,such as age,distance and reddening,derived by isochrone fitting in the color-magnitude diagram（CMD）.These open cluster candidates are stellar density peaks detected in the star density maps by applying the method from Koposov et al. Each candidate is inspected in terms of its true color image composed from three XSTPS-GAC band images. Then its CMD is checked,in order to identify whether the central region stars have a clear isochrone-like trend differing from background stars. The parameters derived from isochrone fitting for these candidates are mainly based on three band photometry of XSTPS-GAC.Moreover,when these new candidates are able to be seen clearly in 2 MASS data,their parameters are also derived based on the 2 MASS（J-H,J） CMD. There are a total of 320 known open clusters rediscovered and 24 new open cluster candidates discovered in this work. Furthermore,the parameters of these new candidates,as well as another 11 previously known open clusters,are properly determined for the first time.
文摘It has been found that there are marked errors in the value of valid opening size of heat-bonded nonwoven fabrics between theoretical calculations and engineering measurements. A new modified theoretical model is advanced in this paper. The equivalent diameter of the pore of a fibre web is used to calculate the valid opening size instead of the maximum diameter of inscribed circle used, because the fibres in practical fibre webs are flexible elastomers with definite diameters and the pore of fibre web may produce deformation in screening teat and engineering usage. The results show that the theoretical calculations coincide well with the engineering measurements. This method offers a theoretical basis for computer simulation to the performance of filters of heatbonded nonwoven fabrics.
文摘When implementing open access, policy pioneers and flagship institutions alike have faced considerable challenges in meeting their own aims and achieving a recognized success. Legitimate authority, sufficient resources and the right timing are crucial, but the professionals charged with implementing policy still need several years to accomplish significant progress. This study defines a methodological standard for evaluating the first generation of open access policies. Evaluating implementation establishes evidence, enables reflection, and may foster the emergence of a second generation of open access policies.While the study is based on a small number of cases, these case studies cover most of the pioneer institutions, present the most significant issues and offer an international overview.Each case is reconstructed individually on the basis of public documents and background information, and supported by interviews with professionals responsible for open access implementation. This article presents the highlights from each case study. The results are utilized to indicate how a second generation of policies might define open access as a key component of digital research infrastructures that provide inputs and outputs for research,teaching and learning in real time.
基金supported by the National Natural Science Foundation of China(NSFC,Grant No.11403004)
文摘This paper presents a preliminary test of the k-th nearest neighbor distance （KNND） method for detecting nearby open clusters based on Gaia-DR1. We select 38 386 nearby stars （〈 100 pc） from the Gaia-DR1 catalog, and then use the KNND method to detect overdense regions in three-dimensional space. We find two overdense regions （the Hyades and Coma Berenices （Coma Ber） open clusters）, and obtain 57 reliable cluster members. Based on these cluster members, the distances to the Hyades and Coma Ber clusters are determined to be 46.0±0.2 and 83.5±0.3 pc, respectively. Our results demonstrate that the KNND method can be used to detect open clusters based on a large volume of astrometry data.
文摘Firstly, this paper theoretically proves that with the development of open economy the effect of monetary policy will become poor. Secondly, the paper empirically analyzes the impact of open economy on our monetary policy. We conclude that there no longer exists long stable relationship between money supply and economic growth. Finally, in four aspects the paper concretely points out that with the open of economy great changes will take place in the implementation of our monetary policy.
文摘It has been our consistent policy to expand the opening policy, while using foreign capital reasonably and effectively. Our experience of economic development since China’s economic reform and opening to the outside world 20 years ago has shown that implementing the opening policy, participation in the international division of labour and exchange, the use of both domestic and international markets and resources, and the introduction of a foreign
文摘China has undergone the three major stages in its development of foreign-invested enterprise: exploratory development, accelerated development and innovative development. This harnessing of foreign investment has resulted in tremendous success for China, including making up for the funds shortage for economic construction, promoting corporate technological progress and management expertise, easing employment pressure, increasing fiscal revenue and boosting trade. At the same time, there have been problems, including questions of economic security, environment and energy issues, unequal competition and problems with the management of foreign-invested enterprises. To promote the development of foreign-invested enterprises in both a healthy and rapid fashion, China should look toward "maintaining policy continuity, promoting the forward-looking nature of policy, strengthening policy guidance and highlighting policy innovativeness."
基金the National Natural Science Foundation of China(NSFC)through grants 12003022,12373035,12233009 and 12173047support from the Youth Innovation Promotion Association of the CAS(grant No.2022055)。
文摘Open clusters are the basic building blocks that serve as a laboratory for the study of young stellar populations in the Milky Way.Variable stars in open clusters provide a unique way to accurately probe the internal structure,temporal and dynamical evolutionary stages of individual stars and the host cluster.The most powerful tool for such studies is time-domain photometric observations.This paper follows the route of our previous work,concentrating on a photometric search for variable stars in NGC 884.The target cluster is the companion of NGC869,forming the well-known double cluster system that is gravitationally bound.From the observation run in 2016 November,a total of 9247 B-band CCD images and 8218Ⅴ-band CCD images were obtained.We detected a total of 15 stars with variability in visual brightness,including five Be stars,three eclipsing binaries,and seven of unknown types.Two new variable stars were discovered in this work.We also compared the variable star content of NGC 884 with its companion NGC 869.
