According to the engineering features of higher pile-column bridge pier in mountainous area, a clamped beam mechanical model was set up by synthetically analyzing the higher pile-column bridge pier buckling mechanism....According to the engineering features of higher pile-column bridge pier in mountainous area, a clamped beam mechanical model was set up by synthetically analyzing the higher pile-column bridge pier buckling mechanism. Based on the catastrophe theory, the cusp catastrophe model of higher pile-column bridge pier was established by the determination of its potential fimction and bifurcation set equation, the necessary instability conditions of high pile-column bridge pier were deduced, and the determination method for column-buckling and lateral displacement of high pile-column bridge pier was derived. The comparison between the experimental and calculated results show that the calculated curves agree with testing curves and the method is reasonable and effective.展开更多
For microseisimic monitoring it is difficult to determine wave modes and their propagation velocity. In this paper, we propose a new method for automatically inverting in real time the source characteristics of micros...For microseisimic monitoring it is difficult to determine wave modes and their propagation velocity. In this paper, we propose a new method for automatically inverting in real time the source characteristics of microseismic events in mine engineering without wave mode identification and velocities. Based on the wave equation in a spherical coordinate system, we derive a tomographic imaging equation and formulate a scanning parameter selection criterion by which the microseisimic event maximum energy and corresponding parameters can be determined. By determining the maximum energy positions inside a given risk district, we can indentify microseismic events inside or outside the risk districts. The synthetic and field examples demonstrate that the proposed tomographic imaging method can automatically position microseismic events by only knowing the risk district dimensions and range of velocities without identifying the wavefield modes and accurate velocities. Therefore, the new method utilizes the full wavefields to automatically monitor microseismic events.展开更多
The high-resolution hypocenter locations of the mainshocks on July 21 (M6.2) and October 16, 2003 (M6.1) and their aftershock sequences are determined in Dayao, Yunnan by using a double-difference earthquake locat...The high-resolution hypocenter locations of the mainshocks on July 21 (M6.2) and October 16, 2003 (M6.1) and their aftershock sequences are determined in Dayao, Yunnan by using a double-difference earthquake location algorithm. The results show that the epicenters of the two mainshocks are very close to each other and the distribution of the aftershock sequence appears to be very linear. The distribution of the earthquake sequence is very consistent with the focal mechanism, and both mainshocks are of nearly vertical right-lateral fault. Unlike most other double earthquakes in the Yunmm area, the aftershock distribution of the M6.2 and M6.1 Dayao earthquakes does not appear to be a conjugated distribution but to be in a line, and there are some stacks in the two earthquake sequences. It can be inferred that they are all controlled by the same fault. The distribution of aftershocks is asymmetrical with respect to the mainshock location and appears to be unilateral. The aftershocks of the M6.2 mainshock centralize in the northwest of M6.2 earthquake and the aftershocks of the M6.1 earthquake are in the southeast of the mainshock, moreover, the M6.1 earthquake appears to be another rupture on the southeastern extensiou of the same fault as the M6.2 earthquake. The results of Coulomb failure static stress changes △σf show that the earthquake on July 21 (M6.2) apparently triggered the earthquake on October 16 (M6.1), the two mainshocks have stress triggering to their off-fault aftershocks to different extents, and the M6.5 earthquake that occurred in Yao'an in 2000 also triggered the occurrence of the two Dayao earthquakes.展开更多
Using the observed daily temperatures from 756 stations in China during the period from 1951 to 2009 extensive and persistent extreme cold events (EPECEs) were defined according to the following three steps:1) a stati...Using the observed daily temperatures from 756 stations in China during the period from 1951 to 2009 extensive and persistent extreme cold events (EPECEs) were defined according to the following three steps:1) a station was defined as an extreme cold station (ECS) if the observed temperature was lower than its 10th percentile threshold;2) an extensive extreme cold event was determined to be present if the approximated area occupied by the ECSs was more than 10% of the total area of China (83rd percentile) on its starting day and the maximum area occupied by the ECSs was at least 20% of the total area of China (96th percentile);and 3) an EPECE was determined to be present if the extensive extreme cold event lasted for at least for eight days.52 EPECEs were identified in this manner,and these identification results were also verified using other reliable data.On the basis of cluster analysis,five types of EPECEs were classified according to the spatial distribution of ECSs at their most extensive time over the course of the EPECE.展开更多
In this paper, we give some conditions on diverging rate of series of the probabilities and converging rate of series of the α-mixing coefficients for sequences of events, under which the conclusion of the Second Bor...In this paper, we give some conditions on diverging rate of series of the probabilities and converging rate of series of the α-mixing coefficients for sequences of events, under which the conclusion of the Second Borel-Cantelli Lemma holds. As corollaries, some moment conditions are obtained, under which the strong law of large numbers holds for sequences of identically distributed random variables.展开更多
In recent years,oil spill accidents occur frequently in the marine area of China.Finding out the spilled oil source is a key step in the relevant investigation.In this paper,a step-by-step fingerprinting identificatio...In recent years,oil spill accidents occur frequently in the marine area of China.Finding out the spilled oil source is a key step in the relevant investigation.In this paper,a step-by-step fingerprinting identification method was used in a spilled oil accident in the Bohai Sea in 2002.Advanced chemical fingerprinting and data interpretation techniques were used to characterize the chemical composition and determine the possible sources of two spilled oil samples.The original gas chromatography -flame ionization detec-tion (GC-FID) chromatogram of saturated hydrocarbons was compared.The gas chromatography-mass spectrometry (GC/MS) chromatograms of aromatic hydrocarbons terpane and sterane,n-alkane and poly-aromatic hydrocarbons (PAHs) were analyzed.The correlation analysis on diagnostic ratios was performed with Student’s t-test.It is found that the oil fingerprinting of the spilled oil (designated as sz1) from the polluted sand beach was identical with the suspected oil (designated as ky1) from a nearby crude oil refinery factory.They both showed the fingerprinting character of mixed oil.The oil fingerprinting of the spilled oil (designated as ms1) collected from the port was significantly different from oil ky1 and oil sz1 and was with a lubricating oil fingerprint character.The identification result not only gave support for the spilled oil investigation,but also served as an example for studying spilled oil accidents.展开更多
Excavation-and-support induced disturbances are likely to make water-enriched roofs to become weathered and fractured.The development and connection of cracks provide new water channels which may result in water loss,...Excavation-and-support induced disturbances are likely to make water-enriched roofs to become weathered and fractured.The development and connection of cracks provide new water channels which may result in water loss,seriously affecting the in-tegrity and stability of roofs,leading to incidents of roof fall.Control of water-enriched rocks surrounding coal drifts is quite diffi-cult in China.Based on the practical situation of a water-enriched roof of a coal drift in working face 112201 of the Meihuajing coal mine,we studied the deformation features of surrounding rocks and the development of fractured areas and analyzed the major reasons for the decrease in load-carrying capacity,indicating that the key to maintain roof stability of this kind of coal drift is water retention.In addition,we proposed a staged control technology consisting of:1) surface grouting;2) cable anchor strengthening and 3) roof grouting,which has proven to be successful in this practical application.Our study indicates that,after the problem of water loss from the water-enriched roof had been effectively solved,a combined support system with high performance bolts can maintain the stability of the bearing structure,resulting in the control of roof stability in this kind of coal drift.展开更多
Dating data, altitude of Neolithic sites, climatic changes from sedimentary records and previous research results were collected and analyzed to detect possible connections between climatic changes and human activitie...Dating data, altitude of Neolithic sites, climatic changes from sedimentary records and previous research results were collected and analyzed to detect possible connections between climatic changes and human activities in the Changjiang River Delta in the Neolithic Age. The results indicated that hydrological changes greatly impacted the human activities in the study region. Low-lying geomorphology made the floods and sea level changes become the important factors affecting human activities, especially the altitude change of human settlements. People usually moved to higher places during the periods characterized by high sea level and frequent floods to escape the negative influences from water body expansion, which resulted in cultural hiatus in certain profiles. However, some higher-altitude settlements were not the results of climatic changes but the results of social factors, such as religious ceremony and social status. Therefore, further research will be necessary for the degree and types of impacts of climatic changes on human activities in the study area at that time.展开更多
In the text of Wolf Totem, there are many spots of indeterminacy left purposely or involuntarily by the author in the depiction of characters, scenes, events and in the use of culture-related expressions, which are to...In the text of Wolf Totem, there are many spots of indeterminacy left purposely or involuntarily by the author in the depiction of characters, scenes, events and in the use of culture-related expressions, which are to be filled in by individual's interpretation through active reading of the work. Howard Goldblatt, as the translator of this work, adopts "creative rewriting" in the translation of Wolf Totem to actualize the indeterminacy and the factors guiding his concretization.展开更多
Previously, the military establishment has been the primary developer and user of micro technologies associated with unmanned systems. As these technologies become available commercially, a need exists to integrate th...Previously, the military establishment has been the primary developer and user of micro technologies associated with unmanned systems. As these technologies become available commercially, a need exists to integrate the use of the technology into local or regional public safety and homeland security incidents. The purpose of this presentation is to explain several key factors to consider when using micro technologies and unmanned systems in support of public safety and homeland security officials. Real time information is critical to the decision making process for public safety and homeland security officials to make assessments and quickly resolve crisis situations. Unmanned micro-vehicles and micro technologies are well suited to remotely observe, gather essential information, and immediately relay it to incident responders. These technologies can provide extremely important support during responses to hostage situations, hazardous environments, search and rescue, natural disasters, border patrol and many others. The true benefit is having remote resources providing real time support to incident responders. This paper discusses the use of several different types of micro-vehicle platforms in public safety scenarios and their use of associated technologies such as GPS (Global Positioning System) autopilot, communication, and sensor devices.展开更多
Discrete-event system simulation technology is used to analyze distribution system reliability in this paper. A simulation model, including entity state models, system state models, state transition models, reliabilit...Discrete-event system simulation technology is used to analyze distribution system reliability in this paper. A simulation model, including entity state models, system state models, state transition models, reliability criterion model, is established. ‘Next happen event’ is taken as impulse principle of simulator clock to determine the sequence of random event occurrence dynamically. The results show this method is feasible.展开更多
In this paper, the conservation laws of generalized Birkhoff system in event space are studied by using the method of integrating factors. Firstly, the generalized Pfaff-Birkhoff principle and the generalized Birkhoff...In this paper, the conservation laws of generalized Birkhoff system in event space are studied by using the method of integrating factors. Firstly, the generalized Pfaff-Birkhoff principle and the generalized Birkhoff equations are established, and the definition of the integrating factors for the system is given. Secondly, based on the concept of integrating factors, the conservation theorems and their inverse for the generalized Birkhoff system in the event space are presented in detail, and the relation between the conservation laws and the integrating factors of the system is obtained and the generalized Killing equations for the determination of the integrating factors are given. Finally, an example is given to illustrate the application of the results.展开更多
A method for placing oil paint in metal tubes occurred in the early 1840s, which facilitated artists taking their materials out of doors to paint nature directly. In France in the 1860s, we know of painters like Claud...A method for placing oil paint in metal tubes occurred in the early 1840s, which facilitated artists taking their materials out of doors to paint nature directly. In France in the 1860s, we know of painters like Claude Monet were working on beaches and port cities to capture the effect of scenes under natural light. By 1874 the Anonymous Society of Painters, Sculptors, Engravers, etc. (Impressionists) offered their first public exhibition to much criticism. A common complaint of the new work was that it lacked finish to be considered as a completed work for sale. It is the view of this paper that outdoor, or plein air painting, developed because of the circumstances this type of work developed in the artist naturally. I focus on two areas that outdoor painting forced the artist to consider: incidents and accidents. The incidents refer to the varied weather the painter had to deal with and the accidents identify the intuitive methods the plein air painters fell practice to when confronted by difficult passages or situations in nature. These experiences would shift the focus of the Impressionists from recording nature in a naturalistic way to self-expression, which would become a key idea in early modem painting. The finish the detractors of Impressionism called for would be replaced by an appreciation for the personal in painting as exacting images of landscape became predictable and lacked the vitality of the intuitive picture that could offer something new to art.展开更多
This study focused on the way that Adolescents with Transfusion- dependent thalassemia explained negative or positive events in their life (Attributional Styles). It is defined by three dimensions describing the cog...This study focused on the way that Adolescents with Transfusion- dependent thalassemia explained negative or positive events in their life (Attributional Styles). It is defined by three dimensions describing the cognitive appraisal of the events: internal-external, stable-unstable, and global-specific. With cross-sectional research design, the observations consist of 102 adolescents (48 males, 54 females) who diagnosed with Transfusion-dependent thalassemia (more than 50 times for blood transfusions) completed the measure of Attributional Styles and Anxiety Questionnaires. The correlations in the predicted directions among variables examine with Pearson product-moment correlation coefficients, t-test, and One-way ANOVA to ascertain a significant between the group differences on attributional factors and levels of anxiety symptoms. The results show that Adolescent samples with higher levels of anxiety revealed statistically significant relationship among three negative attributional dimensions (overall composite F = 4.5, p 〈 0.05; negative composite F = 4.99, p 〈 0.01; negative-internality F = 4.99 p 〈 0.01; negative-stability F = 3.42, p 〈 0.05 and negative-globality F = 3.77, p 〈 0.05). In addition, significant age- group differences were found for the total negative-globality (t = 2.05, p 〈 0.05) and negative- globality (t = -2.22, p 〈 0.05). These data are consistent with the reformulated learned helplessness model of depression. In finding, the individuals who attribute negative life events to internal, stable, and global causes will be more vulnerable to anxiety than those who make external, unstable, and specific attributions. Most interestingly, those adolescents more than 17 years evidence more negative-globality attfibutional style than group less than 16 years, and female adolescents may influence this pattern. These results suggest that targeting Adolescents with Transfusion-dependent thalassemia may be important for improving aspect of coping on psychological adjustment to their chronic illness.展开更多
The 1°×1° National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) data and mesoscale numerical simulation data are analyzed to reveal a mechanism for the form...The 1°×1° National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) data and mesoscale numerical simulation data are analyzed to reveal a mechanism for the formation of heavy rainfall in Northern China; this mechanism is the non-uniformly saturated instability induced by a dry intrusion. The dry intrusion and the accompanying downward transport of air with a high value of potential vorticity (PV) are maintained during the precipitation event. As the dry air intrudes down into the warm and moist sector in the lower troposphere, the cold, dry air and the warm, moist air mix with each other, and, as a result, the atmosphere becomes non-uniformly saturated. On the basis of this non-uniform saturation, a new Brunt-Vaisaila frequency (BVF) formula is derived and applied to the precipitation event. It is shown that, compared to the conditions of either a dry or a saturated atmosphere, the BVF in a non-uniformly saturated, moist atmosphere (BVF) may be more appropriate for depicting the atmospheric instability in rainy regions.展开更多
Turkish people traditionally make good soldiers. In the Republican Turkey, the draft [conscript service system is the valid application whereby privates (rankless plain soldiers)] are recruited from among healthy an...Turkish people traditionally make good soldiers. In the Republican Turkey, the draft [conscript service system is the valid application whereby privates (rankless plain soldiers)] are recruited from among healthy and young male citizens, for a specific term specified by law. Such draftees (conscrips) constitute the backbone of the military man-power. Their numbers attain figures much bigger than the numbers of rank-carrying personnel, namely the petty-officers and officers (generals are very few in number). It is a widely known fact that military life, all over the world, is indeed tough and this is especially true for the rank-and-file, who constitute the lowest levels or the base of the involved hierarchical pyramide. When conscripted for the service, the crushing majority of the young lads go to serve willingly (see Figure 1) and proudly and even with pleasure (see Figure 2). Those who do not readily render themselves to the armed forces are only a small minority. The reason for that is the high prestige enjoyed by all military personnel within the society. Deeply-rooted historical and cultural interpretations come into play, to make us understand the significance and even the sacredness of the armed service. Indeed, merely a collection of songs and ballads praising military themes, justifies the high value of soldierly ways for Turkisp people.展开更多
The old-aged confrontation between “East” and “West”, between “civilization” and “barbarism”, between “Christianity” and “Islam” came to new heights in the early modern times and found its arena in Central...The old-aged confrontation between “East” and “West”, between “civilization” and “barbarism”, between “Christianity” and “Islam” came to new heights in the early modern times and found its arena in Central Europe. Since the late 15th century, the Ottoman Turks had been feared as menace, as the most dreadful enemies not only of the inhabitants of the Habsburg ruled countries but of the whole world of Christianity, and the Ottoman Turks did pose a permanent threat to their neighbours in Central Europe. The situation changed around 1700 when the Habsburgs succeeded in integrating the entire Hungarian Kingdom into their empire. From the early 18th century onwards the Ottoman Turks were no longer regarded as fierce fighters but increasingly as neighbours living in an unknown and totally different world and gained more and more curious attention. This change was not only the consequence of the new balance in power politics but mainly a sequel of gaining much more information. Up to the late 17th century the knowledge about the Ottoman Turks was based primarily on what had been reported by ambassadors travelling to Constantinople while in the 18th century people of several strands of life reported about their experiences. After the Peace of Passarowitz in 1718 trade agreements between the two states enabled activities of merchants and tradesmen who learned to know things about their eastern neighbours which were totally new to the Middle European contemporaries. Additionally, some elements of this "oriental" culture were taken over and were to become typical for Central Europe later on. The Turks were curiously observed as strange and fascinating neighbours. In the course of the movement of enlightenment from the middle of the 18th century onwards one aspect of this culture lost much of its dreadfulness: the fact that the Ottoman Turks were infidels. So it did not take very long until Ottomans were seen as being capable of true humanity regardless their religion. In the 19th century the multiethnic state organizations of the Ottoman Empire and the Habsburg Monarchy became outmoded in this age of nationalism. They realized their common interests and started a cooperation which eventually ended up as alliance in theWorld War I. From the point of view of power politics however, the Ottoman Empire was regarded as “sick man at the Bosporus”. In the following the changes of the image are shown as an overview by observing the criteria against the background of the most important historical events. The details of how this process worked are still pretty murky. Further investigations are already on the way and will bring more light into the reasons and the mechanism of this development.展开更多
This paper deals with the operation and performance of VSC (voltage source converter) based HVDC (high voltage direct current) interconnecting two extremely weak AC networks, the experience of Caprivilink project....This paper deals with the operation and performance of VSC (voltage source converter) based HVDC (high voltage direct current) interconnecting two extremely weak AC networks, the experience of Caprivilink project. It is shown in the paper that the HVDC converter automatically provides the supreme voltage and frequency stabilizing function when a critical situation is detected, no matter the disturbances appeared in sending end or receiving end AC networks. This supreme voltage and frequency stabilizing function makes it possible to avoid the blackout even if all the generators are tripped under an extra-ordinary worst contingency. By plots of recorded transients, the paper will show how the eventual blackouts are avoided.展开更多
基金Project(50578060) supported by the National Natural Science Foundation of China
文摘According to the engineering features of higher pile-column bridge pier in mountainous area, a clamped beam mechanical model was set up by synthetically analyzing the higher pile-column bridge pier buckling mechanism. Based on the catastrophe theory, the cusp catastrophe model of higher pile-column bridge pier was established by the determination of its potential fimction and bifurcation set equation, the necessary instability conditions of high pile-column bridge pier were deduced, and the determination method for column-buckling and lateral displacement of high pile-column bridge pier was derived. The comparison between the experimental and calculated results show that the calculated curves agree with testing curves and the method is reasonable and effective.
基金support jointly by projects of the National Natural Science Fund Project (40674017 and 50774012)the National Key Basic Research and Development Plan 973 (2010CB226803)
文摘For microseisimic monitoring it is difficult to determine wave modes and their propagation velocity. In this paper, we propose a new method for automatically inverting in real time the source characteristics of microseismic events in mine engineering without wave mode identification and velocities. Based on the wave equation in a spherical coordinate system, we derive a tomographic imaging equation and formulate a scanning parameter selection criterion by which the microseisimic event maximum energy and corresponding parameters can be determined. By determining the maximum energy positions inside a given risk district, we can indentify microseismic events inside or outside the risk districts. The synthetic and field examples demonstrate that the proposed tomographic imaging method can automatically position microseismic events by only knowing the risk district dimensions and range of velocities without identifying the wavefield modes and accurate velocities. Therefore, the new method utilizes the full wavefields to automatically monitor microseismic events.
基金This project was sponsored by the National Programon KeyBasic Research Projects (2004CB418406) ,the Programfor the Tenth"Five-Year Plan"of China (2004BA601B01-04-03) andthe Joint Earthquake Science Foundation of China (606042) .
文摘The high-resolution hypocenter locations of the mainshocks on July 21 (M6.2) and October 16, 2003 (M6.1) and their aftershock sequences are determined in Dayao, Yunnan by using a double-difference earthquake location algorithm. The results show that the epicenters of the two mainshocks are very close to each other and the distribution of the aftershock sequence appears to be very linear. The distribution of the earthquake sequence is very consistent with the focal mechanism, and both mainshocks are of nearly vertical right-lateral fault. Unlike most other double earthquakes in the Yunmm area, the aftershock distribution of the M6.2 and M6.1 Dayao earthquakes does not appear to be a conjugated distribution but to be in a line, and there are some stacks in the two earthquake sequences. It can be inferred that they are all controlled by the same fault. The distribution of aftershocks is asymmetrical with respect to the mainshock location and appears to be unilateral. The aftershocks of the M6.2 mainshock centralize in the northwest of M6.2 earthquake and the aftershocks of the M6.1 earthquake are in the southeast of the mainshock, moreover, the M6.1 earthquake appears to be another rupture on the southeastern extensiou of the same fault as the M6.2 earthquake. The results of Coulomb failure static stress changes △σf show that the earthquake on July 21 (M6.2) apparently triggered the earthquake on October 16 (M6.1), the two mainshocks have stress triggering to their off-fault aftershocks to different extents, and the M6.5 earthquake that occurred in Yao'an in 2000 also triggered the occurrence of the two Dayao earthquakes.
基金supportedby the National Key Technologies R&D Program of China (Grant No. 2009BAC51B02)the Special Funds for Meteorology Scientific Research on Public Cause (Grant No. GYHY201106015)
文摘Using the observed daily temperatures from 756 stations in China during the period from 1951 to 2009 extensive and persistent extreme cold events (EPECEs) were defined according to the following three steps:1) a station was defined as an extreme cold station (ECS) if the observed temperature was lower than its 10th percentile threshold;2) an extensive extreme cold event was determined to be present if the approximated area occupied by the ECSs was more than 10% of the total area of China (83rd percentile) on its starting day and the maximum area occupied by the ECSs was at least 20% of the total area of China (96th percentile);and 3) an EPECE was determined to be present if the extensive extreme cold event lasted for at least for eight days.52 EPECEs were identified in this manner,and these identification results were also verified using other reliable data.On the basis of cluster analysis,five types of EPECEs were classified according to the spatial distribution of ECSs at their most extensive time over the course of the EPECE.
基金Supported by the SCR of Chongqing Municipal Education Commission(KJ090703)
文摘In this paper, we give some conditions on diverging rate of series of the probabilities and converging rate of series of the α-mixing coefficients for sequences of events, under which the conclusion of the Second Borel-Cantelli Lemma holds. As corollaries, some moment conditions are obtained, under which the strong law of large numbers holds for sequences of identically distributed random variables.
文摘In recent years,oil spill accidents occur frequently in the marine area of China.Finding out the spilled oil source is a key step in the relevant investigation.In this paper,a step-by-step fingerprinting identification method was used in a spilled oil accident in the Bohai Sea in 2002.Advanced chemical fingerprinting and data interpretation techniques were used to characterize the chemical composition and determine the possible sources of two spilled oil samples.The original gas chromatography -flame ionization detec-tion (GC-FID) chromatogram of saturated hydrocarbons was compared.The gas chromatography-mass spectrometry (GC/MS) chromatograms of aromatic hydrocarbons terpane and sterane,n-alkane and poly-aromatic hydrocarbons (PAHs) were analyzed.The correlation analysis on diagnostic ratios was performed with Student’s t-test.It is found that the oil fingerprinting of the spilled oil (designated as sz1) from the polluted sand beach was identical with the suspected oil (designated as ky1) from a nearby crude oil refinery factory.They both showed the fingerprinting character of mixed oil.The oil fingerprinting of the spilled oil (designated as ms1) collected from the port was significantly different from oil ky1 and oil sz1 and was with a lubricating oil fingerprint character.The identification result not only gave support for the spilled oil investigation,but also served as an example for studying spilled oil accidents.
基金Projects 50674085 supported by the Qing Lan Project of Jiangsu Provicne50774077 by the National Natural Science Foundation of China
文摘Excavation-and-support induced disturbances are likely to make water-enriched roofs to become weathered and fractured.The development and connection of cracks provide new water channels which may result in water loss,seriously affecting the in-tegrity and stability of roofs,leading to incidents of roof fall.Control of water-enriched rocks surrounding coal drifts is quite diffi-cult in China.Based on the practical situation of a water-enriched roof of a coal drift in working face 112201 of the Meihuajing coal mine,we studied the deformation features of surrounding rocks and the development of fractured areas and analyzed the major reasons for the decrease in load-carrying capacity,indicating that the key to maintain roof stability of this kind of coal drift is water retention.In addition,we proposed a staged control technology consisting of:1) surface grouting;2) cable anchor strengthening and 3) roof grouting,which has proven to be successful in this practical application.Our study indicates that,after the problem of water loss from the water-enriched roof had been effectively solved,a combined support system with high performance bolts can maintain the stability of the bearing structure,resulting in the control of roof stability in this kind of coal drift.
基金Under the auspices of K. C. WANG Education Foundation Hong Kong+1 种基金 the National Postdoctoral Foundation of China and Key Project of Chinese Academy of Sciences (No. KZCX3-SW-331)
文摘Dating data, altitude of Neolithic sites, climatic changes from sedimentary records and previous research results were collected and analyzed to detect possible connections between climatic changes and human activities in the Changjiang River Delta in the Neolithic Age. The results indicated that hydrological changes greatly impacted the human activities in the study region. Low-lying geomorphology made the floods and sea level changes become the important factors affecting human activities, especially the altitude change of human settlements. People usually moved to higher places during the periods characterized by high sea level and frequent floods to escape the negative influences from water body expansion, which resulted in cultural hiatus in certain profiles. However, some higher-altitude settlements were not the results of climatic changes but the results of social factors, such as religious ceremony and social status. Therefore, further research will be necessary for the degree and types of impacts of climatic changes on human activities in the study area at that time.
文摘In the text of Wolf Totem, there are many spots of indeterminacy left purposely or involuntarily by the author in the depiction of characters, scenes, events and in the use of culture-related expressions, which are to be filled in by individual's interpretation through active reading of the work. Howard Goldblatt, as the translator of this work, adopts "creative rewriting" in the translation of Wolf Totem to actualize the indeterminacy and the factors guiding his concretization.
文摘Previously, the military establishment has been the primary developer and user of micro technologies associated with unmanned systems. As these technologies become available commercially, a need exists to integrate the use of the technology into local or regional public safety and homeland security incidents. The purpose of this presentation is to explain several key factors to consider when using micro technologies and unmanned systems in support of public safety and homeland security officials. Real time information is critical to the decision making process for public safety and homeland security officials to make assessments and quickly resolve crisis situations. Unmanned micro-vehicles and micro technologies are well suited to remotely observe, gather essential information, and immediately relay it to incident responders. These technologies can provide extremely important support during responses to hostage situations, hazardous environments, search and rescue, natural disasters, border patrol and many others. The true benefit is having remote resources providing real time support to incident responders. This paper discusses the use of several different types of micro-vehicle platforms in public safety scenarios and their use of associated technologies such as GPS (Global Positioning System) autopilot, communication, and sensor devices.
基金SupportedbyNationalNatureScienceFoundation No .5 0 1770 17
文摘Discrete-event system simulation technology is used to analyze distribution system reliability in this paper. A simulation model, including entity state models, system state models, state transition models, reliability criterion model, is established. ‘Next happen event’ is taken as impulse principle of simulator clock to determine the sequence of random event occurrence dynamically. The results show this method is feasible.
基金supported by National Natural Science Foundation of China under Grant No. 10572021
文摘In this paper, the conservation laws of generalized Birkhoff system in event space are studied by using the method of integrating factors. Firstly, the generalized Pfaff-Birkhoff principle and the generalized Birkhoff equations are established, and the definition of the integrating factors for the system is given. Secondly, based on the concept of integrating factors, the conservation theorems and their inverse for the generalized Birkhoff system in the event space are presented in detail, and the relation between the conservation laws and the integrating factors of the system is obtained and the generalized Killing equations for the determination of the integrating factors are given. Finally, an example is given to illustrate the application of the results.
文摘A method for placing oil paint in metal tubes occurred in the early 1840s, which facilitated artists taking their materials out of doors to paint nature directly. In France in the 1860s, we know of painters like Claude Monet were working on beaches and port cities to capture the effect of scenes under natural light. By 1874 the Anonymous Society of Painters, Sculptors, Engravers, etc. (Impressionists) offered their first public exhibition to much criticism. A common complaint of the new work was that it lacked finish to be considered as a completed work for sale. It is the view of this paper that outdoor, or plein air painting, developed because of the circumstances this type of work developed in the artist naturally. I focus on two areas that outdoor painting forced the artist to consider: incidents and accidents. The incidents refer to the varied weather the painter had to deal with and the accidents identify the intuitive methods the plein air painters fell practice to when confronted by difficult passages or situations in nature. These experiences would shift the focus of the Impressionists from recording nature in a naturalistic way to self-expression, which would become a key idea in early modem painting. The finish the detractors of Impressionism called for would be replaced by an appreciation for the personal in painting as exacting images of landscape became predictable and lacked the vitality of the intuitive picture that could offer something new to art.
文摘This study focused on the way that Adolescents with Transfusion- dependent thalassemia explained negative or positive events in their life (Attributional Styles). It is defined by three dimensions describing the cognitive appraisal of the events: internal-external, stable-unstable, and global-specific. With cross-sectional research design, the observations consist of 102 adolescents (48 males, 54 females) who diagnosed with Transfusion-dependent thalassemia (more than 50 times for blood transfusions) completed the measure of Attributional Styles and Anxiety Questionnaires. The correlations in the predicted directions among variables examine with Pearson product-moment correlation coefficients, t-test, and One-way ANOVA to ascertain a significant between the group differences on attributional factors and levels of anxiety symptoms. The results show that Adolescent samples with higher levels of anxiety revealed statistically significant relationship among three negative attributional dimensions (overall composite F = 4.5, p 〈 0.05; negative composite F = 4.99, p 〈 0.01; negative-internality F = 4.99 p 〈 0.01; negative-stability F = 3.42, p 〈 0.05 and negative-globality F = 3.77, p 〈 0.05). In addition, significant age- group differences were found for the total negative-globality (t = 2.05, p 〈 0.05) and negative- globality (t = -2.22, p 〈 0.05). These data are consistent with the reformulated learned helplessness model of depression. In finding, the individuals who attribute negative life events to internal, stable, and global causes will be more vulnerable to anxiety than those who make external, unstable, and specific attributions. Most interestingly, those adolescents more than 17 years evidence more negative-globality attfibutional style than group less than 16 years, and female adolescents may influence this pattern. These results suggest that targeting Adolescents with Transfusion-dependent thalassemia may be important for improving aspect of coping on psychological adjustment to their chronic illness.
基金supported by the National Natural Science Foundation of China (under Grant No. 40805001)the Knowledge Innovation Program of the Chinese Academy of Sciences (under Grant Nos. KCL14014, IAP07201, and IAP07214)
文摘The 1°×1° National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) data and mesoscale numerical simulation data are analyzed to reveal a mechanism for the formation of heavy rainfall in Northern China; this mechanism is the non-uniformly saturated instability induced by a dry intrusion. The dry intrusion and the accompanying downward transport of air with a high value of potential vorticity (PV) are maintained during the precipitation event. As the dry air intrudes down into the warm and moist sector in the lower troposphere, the cold, dry air and the warm, moist air mix with each other, and, as a result, the atmosphere becomes non-uniformly saturated. On the basis of this non-uniform saturation, a new Brunt-Vaisaila frequency (BVF) formula is derived and applied to the precipitation event. It is shown that, compared to the conditions of either a dry or a saturated atmosphere, the BVF in a non-uniformly saturated, moist atmosphere (BVF) may be more appropriate for depicting the atmospheric instability in rainy regions.
文摘Turkish people traditionally make good soldiers. In the Republican Turkey, the draft [conscript service system is the valid application whereby privates (rankless plain soldiers)] are recruited from among healthy and young male citizens, for a specific term specified by law. Such draftees (conscrips) constitute the backbone of the military man-power. Their numbers attain figures much bigger than the numbers of rank-carrying personnel, namely the petty-officers and officers (generals are very few in number). It is a widely known fact that military life, all over the world, is indeed tough and this is especially true for the rank-and-file, who constitute the lowest levels or the base of the involved hierarchical pyramide. When conscripted for the service, the crushing majority of the young lads go to serve willingly (see Figure 1) and proudly and even with pleasure (see Figure 2). Those who do not readily render themselves to the armed forces are only a small minority. The reason for that is the high prestige enjoyed by all military personnel within the society. Deeply-rooted historical and cultural interpretations come into play, to make us understand the significance and even the sacredness of the armed service. Indeed, merely a collection of songs and ballads praising military themes, justifies the high value of soldierly ways for Turkisp people.
文摘The old-aged confrontation between “East” and “West”, between “civilization” and “barbarism”, between “Christianity” and “Islam” came to new heights in the early modern times and found its arena in Central Europe. Since the late 15th century, the Ottoman Turks had been feared as menace, as the most dreadful enemies not only of the inhabitants of the Habsburg ruled countries but of the whole world of Christianity, and the Ottoman Turks did pose a permanent threat to their neighbours in Central Europe. The situation changed around 1700 when the Habsburgs succeeded in integrating the entire Hungarian Kingdom into their empire. From the early 18th century onwards the Ottoman Turks were no longer regarded as fierce fighters but increasingly as neighbours living in an unknown and totally different world and gained more and more curious attention. This change was not only the consequence of the new balance in power politics but mainly a sequel of gaining much more information. Up to the late 17th century the knowledge about the Ottoman Turks was based primarily on what had been reported by ambassadors travelling to Constantinople while in the 18th century people of several strands of life reported about their experiences. After the Peace of Passarowitz in 1718 trade agreements between the two states enabled activities of merchants and tradesmen who learned to know things about their eastern neighbours which were totally new to the Middle European contemporaries. Additionally, some elements of this "oriental" culture were taken over and were to become typical for Central Europe later on. The Turks were curiously observed as strange and fascinating neighbours. In the course of the movement of enlightenment from the middle of the 18th century onwards one aspect of this culture lost much of its dreadfulness: the fact that the Ottoman Turks were infidels. So it did not take very long until Ottomans were seen as being capable of true humanity regardless their religion. In the 19th century the multiethnic state organizations of the Ottoman Empire and the Habsburg Monarchy became outmoded in this age of nationalism. They realized their common interests and started a cooperation which eventually ended up as alliance in theWorld War I. From the point of view of power politics however, the Ottoman Empire was regarded as “sick man at the Bosporus”. In the following the changes of the image are shown as an overview by observing the criteria against the background of the most important historical events. The details of how this process worked are still pretty murky. Further investigations are already on the way and will bring more light into the reasons and the mechanism of this development.
文摘This paper deals with the operation and performance of VSC (voltage source converter) based HVDC (high voltage direct current) interconnecting two extremely weak AC networks, the experience of Caprivilink project. It is shown in the paper that the HVDC converter automatically provides the supreme voltage and frequency stabilizing function when a critical situation is detected, no matter the disturbances appeared in sending end or receiving end AC networks. This supreme voltage and frequency stabilizing function makes it possible to avoid the blackout even if all the generators are tripped under an extra-ordinary worst contingency. By plots of recorded transients, the paper will show how the eventual blackouts are avoided.