In order to study the morphological variations among wild Anthocidaris crassispina groups in the southeast coast of China, six groups collected from Daya Bay, Egong Bay, Hailing Island, and Nan'ao Island in Guangzhou...In order to study the morphological variations among wild Anthocidaris crassispina groups in the southeast coast of China, six groups collected from Daya Bay, Egong Bay, Hailing Island, and Nan'ao Island in Guangzhou Province, Weizhou Island in Guangxi Province and Ningde City in Fujian Province were analyzed in this paper. Six morphometric traits were measured and the degrees of morphological variations among wild Anthocidaris crassispina groups were compared using four multivariate analyses, one-way ANOVA analysis, variation coefficient method, cluster analysis and discriminant analysis. The results of one-way ANOVA analysis showed that there were significant differences in the six morphometric traits between Weizhou Island's population and the other five groups. The variation coefficient analysis showed that the difference between the Weizhou Island's population and Hailing Is- land's population reached the interspecific level. The results of cluster analysis showed that the morphometric characters of Daly Bay's population, Egong Bay's population and Nan'ao's population were more similar, but the groups from Weizhou Island and Ningde City were the most divergent. The discriminant analysis showed that the identification accuracy of A. crassispina was 47.8%-86%, and the total dis- criminant accuracy was 65.3%. All the analysis results above suggest that certain morphological variation has been generated among A. crassispina groups from differ- ent origins due to geographical isolation and different environmental factors.展开更多
The shapes of intrusive body and contact zone might influence the formation and distribution of orebodies in skarn deposit.By taking Xinwuli intrusive body in Fenghuangshan copper deposit,Tongling,Anhui,China,as the r...The shapes of intrusive body and contact zone might influence the formation and distribution of orebodies in skarn deposit.By taking Xinwuli intrusive body in Fenghuangshan copper deposit,Tongling,Anhui,China,as the research object,a new method was used to obtain the quantitative relationship between intrusion morphology and skarn mineralization.The first step of the method was to extract morphological characteristic parameters based on mathematical morphology and Euclidean distance transformation;then the quantitative relationship between the parameters and orebodies was analyzed;finally correlational analyses between the parameters and mineralization indices were conducted.The results show that morphological characteristic parameters can effectively indicate the location of concealed ore bodies in skarn deposit,with the following parts as advantageous positions of skarn mineralization:(1)the parts away from the1st trend surface in the range from?25to50m;(2)the convex parts about200m away from the2nd trend surface,around which the tangent plane of the intrusive body is approximately consistent with the trend surface;(3)the contact zones with angle between intrusive body original contact surface and trend contact surface ranging from35°to70°;(4)the parts with angle between intrusive body original contact surface and regional extruding far crustal stress ranging from50°to60°.These knowledge can be applied to more skarn deposits for future mineral exploration.展开更多
For deep mining engineering, heat transfer of coal mass is a vital factor in the thermal environment of coal mines. In order to study the thermal conduction mechanism, we obtained gray images of coal mass microstructu...For deep mining engineering, heat transfer of coal mass is a vital factor in the thermal environment of coal mines. In order to study the thermal conduction mechanism, we obtained gray images of coal mass microstructure by scanning samples with a digital microscope. With the use of Matlab, these gray images were transformed into binary images, which were then transformed into a corresponding matrix consisting only of the values 0 and 1. According to the calculation method of box-counting dimension, we calculated the fractal dimension of the loose coal to be approximately 1.86. The thermal conductivity expressions of loose coal were derived based on the simulation method of thermal resistance. We calculated the thermal conductivity of loose coal by using a fractal model and compared the calculated values with our experimental data. The results show that the test data show an encourag-ing agreement with the calculated values. Hence fractal theory is a feasible method for studying thermal conductivity of loose coal.展开更多
To investigate the effective shape of collapsing block in square tunnel subjected to pore water pressure,the analytical solution of detaching curve was derived using upper bound theorem of limit analysis with Hoek-Bro...To investigate the effective shape of collapsing block in square tunnel subjected to pore water pressure,the analytical solution of detaching curve was derived using upper bound theorem of limit analysis with Hoek-Brown failure criterion. The work rate of pore water pressure,which was regarded as an external rate of work,was taken into account in the framework of limit analysis. Taking advantages of variational calculation,the objective function with respect to detaching curve was optimized to obtain the effective shape of collapsing block for square tunnel. According to the numerical results,it is found that the varying pore water pressure coefficient only affects the height and width of the collapsing block,whereas the shape of collapsing block remains unchanged.展开更多
Schwannoma is a well-described,benign nerve sheath tumor of the soft tissue,but is rare in the gastrointestinal tract.Gastrointestinal schwannomas are often incidentally discovered as small polypoid intraluminal lesio...Schwannoma is a well-described,benign nerve sheath tumor of the soft tissue,but is rare in the gastrointestinal tract.Gastrointestinal schwannomas are often incidentally discovered as small polypoid intraluminal lesions.In this report,we describe the clinicopathologic and immunohistochemical features of a distinctive neural mucosal polyp composed of a diffuse cellular proliferation of uniform bland spindled cells in the lamina propria that entraps the colonic crypts.Immunohistochemical analysis revealed strong and diffuse positivity for the S-100 protein.To avoid confusion of these solitary colorectal polyps containing pure spindled Schwann cell proliferation in the lamina propria with neural lesions that have significant association with inherited syndromes,it is better to use the designation "mucosal Schwann hamartoma".展开更多
The overbroken rock mass of gob areas is made up of broken and accumulated rock blocks compressed to some extent by the overlying strata. The beating pressure of the gob can directly affect the safety of mining fields...The overbroken rock mass of gob areas is made up of broken and accumulated rock blocks compressed to some extent by the overlying strata. The beating pressure of the gob can directly affect the safety of mining fields, formarion of road retained along the next goaf and seepage of water and methane through the gob. In this paper, the software RFPA'2000 is used to construct numerical models. Especially the Euler method of control volume is proposed to solve the simulation difficulty arising from plastically finite deformations. The results show that three characteristic regions occurred in the gob area: (1) a naturally accumulated region, 0-10 m away from unbroken surrounding rock walls, where the beating pressure is nearly zero; (2) an overcompacted region, 10-20 m away from unbroken walls, where the beating pressure results in the maximum value of the gob area; (3) a stable compaction region, more than 20 m away from unbroken walls and occupying absolutely most of the gob area, where the beating pressures show basically no differences. Such a characteristic can exolain the easy-seeoaged “O”-ring phenomena around mining fields very well.展开更多
In this paper the large deflection dynamic problems of Euler beams are investigated. The vibration control equations are derived based on the multibody system method. A numerical procedure for solving the resulting di...In this paper the large deflection dynamic problems of Euler beams are investigated. The vibration control equations are derived based on the multibody system method. A numerical procedure for solving the resulting differential algebraic equations is presented on the basis of the Newmark direct integration method combined with the Newton-Raphson iterative method. The sub beams are treated as small deformation in the convected coordinate systems, which can greatly simplify the deformation description. The rigid motions of the sub beams are taken into account through the motions of the convected coordinate systems. Numerical ex- amples are carried out, where results show the effectiveness of the proposed method.展开更多
The analytical mathematical solutions of gas concentration and fractional gas loss for the diffusion of gas in a cylindrical coal sample were given with detailed mathematical derivations by assuming that the diffusion...The analytical mathematical solutions of gas concentration and fractional gas loss for the diffusion of gas in a cylindrical coal sample were given with detailed mathematical derivations by assuming that the diffusion of gas through the coal matrix is concentration gradient-driven and obeys the Fick’s Second Law of Diffusion.The analytical solutions were approximated in case of small values of time and the error analyses associated with the approximation were also undertaken.The results indicate that the square root relationship of gas release in the early stage of desorption,which is widely used to provide a simple and fast estimation of the lost gas,is the first term of the approximation,and care must be taken in using the square root relationship as a significant error might be introduced with increase in the lost time and decrease in effective diameter of a cylindrical coal sample.展开更多
The hard tissues of squid can provide important information for species identification. In this study, we used statolith and beak to identify three squid species including Uroteuthis duvaucelii, Loliolus beka, and U. ...The hard tissues of squid can provide important information for species identification. In this study, we used statolith and beak to identify three squid species including Uroteuthis duvaucelii, Loliolus beka, and U. edulis in the South China Sea. Because of the highly overlapping habitat and similar body morphology of the three squid species, we explored four different ways to identify them, by using statolith, upper beak, lower beak and a combination of statolith and beak. An outline geometric morphometric method and stepwise discriminant analysis were used to evaluate the most suitable method for the identification. We found that the combination of statolith and beak had the highest cross validation rate that was 75.0%, 87.5% and 88.7% for U. duvaucelii, L. beka and U. edulis, respectively. Using two beaks had similar results and the lowest cross validation rate was 60.0%, 50.0%, and 73.7% for the upper beak, 46.9%, 58.5% and 75.3% for the lower beak of U. duvaucelii, L. beka and U. edulis, respectively. Analyzing with the statolith had moderate cross validation which was 72.2%, 80.0%, and 87.7% for U. duvaucelii, L. beka and U. edulis, respectively. From the results it is suggested when the entire body of a squid is available, a combination of statolith and beak should be used for the identification. When only one hard tissue is available, species identification can be subjected to large errors.展开更多
As a growing number of countries, including both developed and developing countries, have in recent yearstaken environmental regulation at different levels, a question of great concern has been raised: can the regulat...As a growing number of countries, including both developed and developing countries, have in recent yearstaken environmental regulation at different levels, a question of great concern has been raised: can the regulation alterthe existing trade volume and trade pattern, and ultimately drive pollution-intensive industries to countries with low-levelregulations or even those without regulations at all? Starting from the three different propositions concerning therelationship between environmental regulation and trade pattern, this paper applies cointegration analysis and errorcorrection model to empirically testing the relationship between environmental regulation and trade in China during theperiod of 1985-2005. Our empirical results indicate that in the short run the collection of pollution discharge fees bearsa positive impact on the export share of clean products of total exports. Thus, higher pollution discharge fees raise theratio of clean products exports to total exports. This further indicates that more stringent environmental regulationpromotes the exports of clean products. In the long run pollution discharge fees are positively correlated with the exportshare of clean products but negatively associated with their import share. Such correlations imply that environmentalregulation tends to facilitate the international specialization in line with comparative advantages.展开更多
The aim of this study was to assess the effect of long-term in vitro sub-culturing on the varietal degeneration of three sweet potato varieties, namely, Monate, Mokone and Ndou which were sub-cultured for 32, 23 and 1...The aim of this study was to assess the effect of long-term in vitro sub-culturing on the varietal degeneration of three sweet potato varieties, namely, Monate, Mokone and Ndou which were sub-cultured for 32, 23 and 12 generations, respectively. Each generation was cultured in a media which is made from 4.43 g/L Murashige and Skoog (MS), 30 g/L sucrose and 2 g/L gelrite, respectively, and grown under 16 h light and 8 h dark photoperiod for 30 d. For each generation, 45 plantlets were acclimatized for two months in a glasshouse. Data on in vitro growth performance and 11 morphological characteristics during acclimatization were recorded. Early root and shoot formation was observed after the 27th and 21st sub-cultured generations of Monate and Mokone, respectively. During acclimatization, plantlets from the same variety showed differences in morphological traits such as leaf colour, abaxial leaf pigmentation, vine pigmentation, petiole pigmentation, leaf wrinkling and flowering. However, the rate of these morphological differences is random and irrespective to increase in sub-culturing. Therefore, to understand the genetic base of these morphological variability, two plantlets from each variety were subjected to genetic analysis by using five simple sequence repeat (SSR) primers (IB-242, IB-318, IB-255F, 1B-248 and IB-255). Although SSR loci IB-255F and IB-318 could distinguish between the three varieties, there were no allelic polymorphisms detected in plantlets from the same varieties. Therefore, long-term sub-culturing do not leads to quality degeneration in the three sweet potato varieties.展开更多
Arthritis, most notably rheumatoid arthritis, can destroy the surfaces of the bones; the ideal solution for this is T JR (total joint replacement), which would restore joint functionality, maintain correct aesthetic...Arthritis, most notably rheumatoid arthritis, can destroy the surfaces of the bones; the ideal solution for this is T JR (total joint replacement), which would restore joint functionality, maintain correct aesthetics and eradicate pain for the patient. Current metacarpophalangeal TJR do not provide the normal biomechanical range of motion and functionality. The proposed design attempts to correct this through the use of design geometry and functional anatomy. Numerical analysis is used in conjunction with computational solid modeling to compare a one-piece silicone implant with the proposed T JR. Peak stresses during flexion for the proposed design did not exceed 1.2 MPa, where as soft implants approach 100 MPa to 1,000 MPa for peak stress values. The proposed design, due to high stress tolerances with low deformation, along with functionality and biomechanics, seems to be an appropriate replacement for one-piece silicone implant.展开更多
The relationship between Sacks body strain deformation at Beida No. 200 station in Changping and tidal solids,atmospheric pressure and water level is analyzed in this paper. Sacks body strain deformation data before t...The relationship between Sacks body strain deformation at Beida No. 200 station in Changping and tidal solids,atmospheric pressure and water level is analyzed in this paper. Sacks body strain deformation data before the M_S8. 0 Wenchuan earthquake is studied based on the analysis of the interference. The short-impending anomaly of the body strain deformation is considered to be reliable. The anomaly characteristics conclude:( 1) The trend anomaly as extensional change of the body strain deformations on a quasi 1 year time scale before the Wenchuan earthquake was recorded, and the accumulative amount was about 4000 × 10^(-9). Correspondingly,the short-term precursor of earthquake was manifested as an extensional abrupt change.( 2) The extensional intermittent anomalous abrupt change was recorded by body strainmeters between March1 and May 7 in 2008.( 3) Four compressional abrupt changes were recorded in the intermittent distortions recorded between April 13 and May 11.( 4) High frequency components were increased in the distortion process in May 1 to 3,5,7,and 9 to 12,caused by slow earthquakes before the Wenchuan earthquake according to wavelet analysis. The abnormal phenomena are summarized and the mechanics discussed in this paper. Strain solid tide distortions in body strain observations,the continuous repeated extensional and compressional abrupt changes accompanying these distortions,and the increase of high frequency components can be regarded as the index of short term and impending earthquake prediction,based on analysis of interference factors such as air pressure and water level.展开更多
In this paper, the chaotic dynamics in an attitude transition maneuver of a slosh-spacecraft coupled with flexible appendage in going from minor axis to major axis spin under the influence of dissipative effects due t...In this paper, the chaotic dynamics in an attitude transition maneuver of a slosh-spacecraft coupled with flexible appendage in going from minor axis to major axis spin under the influence of dissipative effects due to fuel slosh and a small flexible appendage constrained to only torsional vibration is investigated. The slosh-spacecraft coupled with flexible appendage in attitude maneuver carrying a sloshing liquid is considered as multi-body system with the sloshing motion modeled as a spherical pendulum. The focus in this paper is that the dynamics of the liquid and flexible appendage vibration are coupled. The equations of motion are derived and transformed into a form suitable for the application of Melnikov’s method. Melnikov’s integral is used to predict the transversal intersections of the stable and unstable manifolds for the perturbed system. An analytical criterion for chaotic motion is derived in terms of system parameters. This criterion is evaluated for its significance to the design of spacecraft. The dependence of the onset of chaos on quantities such as body shape and magnitude of damping values, fuel fraction and torsional vibration frequency of flexible appendage are investigated. In addition, we show that a spacecraft carrying a sloshing liquid, after passive reorientation maneuver, will end up with periodic limit motion other than a final major axis spin because of the intrinsic non-linearity of fuel slosh. Furthermore, an extensive numerical simulation is carried out to validate the Melnikov’s analytical result.展开更多
The three-dimensional discontinuous deformation analysis(3D-DDA) is a promising numerical method for both static and dynamic analyses of rock systems. Lacking mature software, its popularity is far behind its ability....The three-dimensional discontinuous deformation analysis(3D-DDA) is a promising numerical method for both static and dynamic analyses of rock systems. Lacking mature software, its popularity is far behind its ability. To address this problem, this paper presents a new software architecture from a software engineering viewpoint. Based on 3D-DDA characteristics, the implementation of the proposed architecture has the following merits. Firstly, the software architecture separates data, computing, visualization, and signal control into individual modules. Secondly, data storage and parallel access are fully considered for different conditions. Thirdly, an open computing framework is provided which supports most numerical computing methods; common tools for equation solving and parallel computing are provided for further development. Fourthly, efficient visualization functions are provided by integrating a variety of visualization algorithms. A user-friendly graphical user interface is designed to improve the user experience. Finally, through a set of examples, the software is verified against both analytical solutions and the original code by Dr. Shi Gen Hua.展开更多
In order to address the study of complex systems,the detection of patterns in their dynamics could play a key role in understanding their evolution.In particular,global patterns are required to detect emergent concept...In order to address the study of complex systems,the detection of patterns in their dynamics could play a key role in understanding their evolution.In particular,global patterns are required to detect emergent concepts and trends,some of them of a qualitative nature.Formal concept analysis(FCA) is a theory whose goal is to discover and extract knowledge from qualitative data(organized in concept lattices).In complex environments,such as sport competitions,the large amount of information currently available turns concept lattices into complex networks.The authors analyze how to apply FCA reasoning in order to increase confidence in sports predictions by means of detecting regularities from data through the management of intuitive and natural attributes extracted from publicly available information.The complexity of concept lattices-considered as networks with complex topological structure- is analyzed.It is applied to building a knowledge based system for confidence-based reasoning,which simulates how humans tend to avoid the complexity of concept networks by means of bounded reasoning skills.展开更多
The pulsatile flow of blood in a tapered narrow artery with overlapping time-dependent stenosis is mathematically analyzed, modeling blood as Caxreau fluid. Perturbation method is employed for solving the resulting no...The pulsatile flow of blood in a tapered narrow artery with overlapping time-dependent stenosis is mathematically analyzed, modeling blood as Caxreau fluid. Perturbation method is employed for solving the resulting nonlinear system of equations along with the appropriate boundary conditions. The analytic solutions to the pressure gradient, velocity distribution, flow rate, wall shear stress and longitudinal impedance to flow axe obtained in the asymptotic form. The variation of the aforesaid flow quantities with respect to various physical parameters such as maximum depth of the stenosis, angle of tapering of the artery, power law index, Reynolds number, pulsatile amplitude of the flow and Weissenberg number is investigated. It is found that the wall shear stress and longitudinal impedance to flow increase with the increase of the angle of tapering of the artery, the maximum depth of the stenosis and pulsatile Reynolds number and these decrease with the increase of the amplitude of the flow, power law index and Weis- senberg number. The mean velocity of blood decreases significantly with the increase of the artery radius, maximum depth of the stenosis, angle of tapering of the artery.展开更多
基金Supported by National Key Technology Research and Development Program(2012BAD18B02,2012BAD18B01-2)Special Scientific Research Fund of Marine Public Welfare Profession of China(201205021-3)National Nonprofit Institute Research Grant of CATAS-TCGRI(2015TS05)~~
文摘In order to study the morphological variations among wild Anthocidaris crassispina groups in the southeast coast of China, six groups collected from Daya Bay, Egong Bay, Hailing Island, and Nan'ao Island in Guangzhou Province, Weizhou Island in Guangxi Province and Ningde City in Fujian Province were analyzed in this paper. Six morphometric traits were measured and the degrees of morphological variations among wild Anthocidaris crassispina groups were compared using four multivariate analyses, one-way ANOVA analysis, variation coefficient method, cluster analysis and discriminant analysis. The results of one-way ANOVA analysis showed that there were significant differences in the six morphometric traits between Weizhou Island's population and the other five groups. The variation coefficient analysis showed that the difference between the Weizhou Island's population and Hailing Is- land's population reached the interspecific level. The results of cluster analysis showed that the morphometric characters of Daly Bay's population, Egong Bay's population and Nan'ao's population were more similar, but the groups from Weizhou Island and Ningde City were the most divergent. The discriminant analysis showed that the identification accuracy of A. crassispina was 47.8%-86%, and the total dis- criminant accuracy was 65.3%. All the analysis results above suggest that certain morphological variation has been generated among A. crassispina groups from differ- ent origins due to geographical isolation and different environmental factors.
基金Projects(41472301,41472302) supported by the National Natural Science Foundation of China
文摘The shapes of intrusive body and contact zone might influence the formation and distribution of orebodies in skarn deposit.By taking Xinwuli intrusive body in Fenghuangshan copper deposit,Tongling,Anhui,China,as the research object,a new method was used to obtain the quantitative relationship between intrusion morphology and skarn mineralization.The first step of the method was to extract morphological characteristic parameters based on mathematical morphology and Euclidean distance transformation;then the quantitative relationship between the parameters and orebodies was analyzed;finally correlational analyses between the parameters and mineralization indices were conducted.The results show that morphological characteristic parameters can effectively indicate the location of concealed ore bodies in skarn deposit,with the following parts as advantageous positions of skarn mineralization:(1)the parts away from the1st trend surface in the range from?25to50m;(2)the convex parts about200m away from the2nd trend surface,around which the tangent plane of the intrusive body is approximately consistent with the trend surface;(3)the contact zones with angle between intrusive body original contact surface and trend contact surface ranging from35°to70°;(4)the parts with angle between intrusive body original contact surface and regional extruding far crustal stress ranging from50°to60°.These knowledge can be applied to more skarn deposits for future mineral exploration.
基金support for this study, provided by the National Natural Science Foundation of China (Nos50534040 and 50974117)the Research Fund of the State Key Laboratory of Coal Resources & Mine Safety, CUMT (No07KF10)
文摘For deep mining engineering, heat transfer of coal mass is a vital factor in the thermal environment of coal mines. In order to study the thermal conduction mechanism, we obtained gray images of coal mass microstructure by scanning samples with a digital microscope. With the use of Matlab, these gray images were transformed into binary images, which were then transformed into a corresponding matrix consisting only of the values 0 and 1. According to the calculation method of box-counting dimension, we calculated the fractal dimension of the loose coal to be approximately 1.86. The thermal conductivity expressions of loose coal were derived based on the simulation method of thermal resistance. We calculated the thermal conductivity of loose coal by using a fractal model and compared the calculated values with our experimental data. The results show that the test data show an encourag-ing agreement with the calculated values. Hence fractal theory is a feasible method for studying thermal conductivity of loose coal.
基金Project(09JJ1008) supported by Hunan Provincial Science Foundation, ChinaProject(CX2009B043) supported by Hunan Provincial Postgraduate Innovation Program, China
文摘To investigate the effective shape of collapsing block in square tunnel subjected to pore water pressure,the analytical solution of detaching curve was derived using upper bound theorem of limit analysis with Hoek-Brown failure criterion. The work rate of pore water pressure,which was regarded as an external rate of work,was taken into account in the framework of limit analysis. Taking advantages of variational calculation,the objective function with respect to detaching curve was optimized to obtain the effective shape of collapsing block for square tunnel. According to the numerical results,it is found that the varying pore water pressure coefficient only affects the height and width of the collapsing block,whereas the shape of collapsing block remains unchanged.
文摘Schwannoma is a well-described,benign nerve sheath tumor of the soft tissue,but is rare in the gastrointestinal tract.Gastrointestinal schwannomas are often incidentally discovered as small polypoid intraluminal lesions.In this report,we describe the clinicopathologic and immunohistochemical features of a distinctive neural mucosal polyp composed of a diffuse cellular proliferation of uniform bland spindled cells in the lamina propria that entraps the colonic crypts.Immunohistochemical analysis revealed strong and diffuse positivity for the S-100 protein.To avoid confusion of these solitary colorectal polyps containing pure spindled Schwann cell proliferation in the lamina propria with neural lesions that have significant association with inherited syndromes,it is better to use the designation "mucosal Schwann hamartoma".
基金Projects 2005CB221502 supported by the Vital Foundational 973 Program of China, 50225414 by the National Outstanding Youth Foundation,20040350222 by China Postdoctoral Science FoundationBK 2004033 by Jiangsu Natural Science Foundation
文摘The overbroken rock mass of gob areas is made up of broken and accumulated rock blocks compressed to some extent by the overlying strata. The beating pressure of the gob can directly affect the safety of mining fields, formarion of road retained along the next goaf and seepage of water and methane through the gob. In this paper, the software RFPA'2000 is used to construct numerical models. Especially the Euler method of control volume is proposed to solve the simulation difficulty arising from plastically finite deformations. The results show that three characteristic regions occurred in the gob area: (1) a naturally accumulated region, 0-10 m away from unbroken surrounding rock walls, where the beating pressure is nearly zero; (2) an overcompacted region, 10-20 m away from unbroken walls, where the beating pressure results in the maximum value of the gob area; (3) a stable compaction region, more than 20 m away from unbroken walls and occupying absolutely most of the gob area, where the beating pressures show basically no differences. Such a characteristic can exolain the easy-seeoaged “O”-ring phenomena around mining fields very well.
文摘In this paper the large deflection dynamic problems of Euler beams are investigated. The vibration control equations are derived based on the multibody system method. A numerical procedure for solving the resulting differential algebraic equations is presented on the basis of the Newmark direct integration method combined with the Newton-Raphson iterative method. The sub beams are treated as small deformation in the convected coordinate systems, which can greatly simplify the deformation description. The rigid motions of the sub beams are taken into account through the motions of the convected coordinate systems. Numerical ex- amples are carried out, where results show the effectiveness of the proposed method.
基金provided by the Science and Technology Grant of Huainan City of China (No.2013A4001)the Key Research Grant of Shanxi Province of China (No.201303027-1)
文摘The analytical mathematical solutions of gas concentration and fractional gas loss for the diffusion of gas in a cylindrical coal sample were given with detailed mathematical derivations by assuming that the diffusion of gas through the coal matrix is concentration gradient-driven and obeys the Fick’s Second Law of Diffusion.The analytical solutions were approximated in case of small values of time and the error analyses associated with the approximation were also undertaken.The results indicate that the square root relationship of gas release in the early stage of desorption,which is widely used to provide a simple and fast estimation of the lost gas,is the first term of the approximation,and care must be taken in using the square root relationship as a significant error might be introduced with increase in the lost time and decrease in effective diameter of a cylindrical coal sample.
基金the National Natural Science Foundation of China (No. NSFC41476129)the Shanghai Leading Academic Discipline Project (Fisheries Discipline)supported by Shanghai Ocean University International Center for Marine Studies and Shanghai 1000 Talents Program
文摘The hard tissues of squid can provide important information for species identification. In this study, we used statolith and beak to identify three squid species including Uroteuthis duvaucelii, Loliolus beka, and U. edulis in the South China Sea. Because of the highly overlapping habitat and similar body morphology of the three squid species, we explored four different ways to identify them, by using statolith, upper beak, lower beak and a combination of statolith and beak. An outline geometric morphometric method and stepwise discriminant analysis were used to evaluate the most suitable method for the identification. We found that the combination of statolith and beak had the highest cross validation rate that was 75.0%, 87.5% and 88.7% for U. duvaucelii, L. beka and U. edulis, respectively. Using two beaks had similar results and the lowest cross validation rate was 60.0%, 50.0%, and 73.7% for the upper beak, 46.9%, 58.5% and 75.3% for the lower beak of U. duvaucelii, L. beka and U. edulis, respectively. Analyzing with the statolith had moderate cross validation which was 72.2%, 80.0%, and 87.7% for U. duvaucelii, L. beka and U. edulis, respectively. From the results it is suggested when the entire body of a squid is available, a combination of statolith and beak should be used for the identification. When only one hard tissue is available, species identification can be subjected to large errors.
文摘As a growing number of countries, including both developed and developing countries, have in recent yearstaken environmental regulation at different levels, a question of great concern has been raised: can the regulation alterthe existing trade volume and trade pattern, and ultimately drive pollution-intensive industries to countries with low-levelregulations or even those without regulations at all? Starting from the three different propositions concerning therelationship between environmental regulation and trade pattern, this paper applies cointegration analysis and errorcorrection model to empirically testing the relationship between environmental regulation and trade in China during theperiod of 1985-2005. Our empirical results indicate that in the short run the collection of pollution discharge fees bearsa positive impact on the export share of clean products of total exports. Thus, higher pollution discharge fees raise theratio of clean products exports to total exports. This further indicates that more stringent environmental regulationpromotes the exports of clean products. In the long run pollution discharge fees are positively correlated with the exportshare of clean products but negatively associated with their import share. Such correlations imply that environmentalregulation tends to facilitate the international specialization in line with comparative advantages.
文摘The aim of this study was to assess the effect of long-term in vitro sub-culturing on the varietal degeneration of three sweet potato varieties, namely, Monate, Mokone and Ndou which were sub-cultured for 32, 23 and 12 generations, respectively. Each generation was cultured in a media which is made from 4.43 g/L Murashige and Skoog (MS), 30 g/L sucrose and 2 g/L gelrite, respectively, and grown under 16 h light and 8 h dark photoperiod for 30 d. For each generation, 45 plantlets were acclimatized for two months in a glasshouse. Data on in vitro growth performance and 11 morphological characteristics during acclimatization were recorded. Early root and shoot formation was observed after the 27th and 21st sub-cultured generations of Monate and Mokone, respectively. During acclimatization, plantlets from the same variety showed differences in morphological traits such as leaf colour, abaxial leaf pigmentation, vine pigmentation, petiole pigmentation, leaf wrinkling and flowering. However, the rate of these morphological differences is random and irrespective to increase in sub-culturing. Therefore, to understand the genetic base of these morphological variability, two plantlets from each variety were subjected to genetic analysis by using five simple sequence repeat (SSR) primers (IB-242, IB-318, IB-255F, 1B-248 and IB-255). Although SSR loci IB-255F and IB-318 could distinguish between the three varieties, there were no allelic polymorphisms detected in plantlets from the same varieties. Therefore, long-term sub-culturing do not leads to quality degeneration in the three sweet potato varieties.
文摘Arthritis, most notably rheumatoid arthritis, can destroy the surfaces of the bones; the ideal solution for this is T JR (total joint replacement), which would restore joint functionality, maintain correct aesthetics and eradicate pain for the patient. Current metacarpophalangeal TJR do not provide the normal biomechanical range of motion and functionality. The proposed design attempts to correct this through the use of design geometry and functional anatomy. Numerical analysis is used in conjunction with computational solid modeling to compare a one-piece silicone implant with the proposed T JR. Peak stresses during flexion for the proposed design did not exceed 1.2 MPa, where as soft implants approach 100 MPa to 1,000 MPa for peak stress values. The proposed design, due to high stress tolerances with low deformation, along with functionality and biomechanics, seems to be an appropriate replacement for one-piece silicone implant.
基金funded by the Three-in-One Project of Earthquake Monitoring,Forecasting and Scientific Research of China Earthquake Administration:Statistical Research on Earthquake Cases of Short-impending Anomalies of Sacks Body Strain(154201)Operation and Maintenance of the Shisanling(Ming Tombs)Seismic Station(40417600105)
文摘The relationship between Sacks body strain deformation at Beida No. 200 station in Changping and tidal solids,atmospheric pressure and water level is analyzed in this paper. Sacks body strain deformation data before the M_S8. 0 Wenchuan earthquake is studied based on the analysis of the interference. The short-impending anomaly of the body strain deformation is considered to be reliable. The anomaly characteristics conclude:( 1) The trend anomaly as extensional change of the body strain deformations on a quasi 1 year time scale before the Wenchuan earthquake was recorded, and the accumulative amount was about 4000 × 10^(-9). Correspondingly,the short-term precursor of earthquake was manifested as an extensional abrupt change.( 2) The extensional intermittent anomalous abrupt change was recorded by body strainmeters between March1 and May 7 in 2008.( 3) Four compressional abrupt changes were recorded in the intermittent distortions recorded between April 13 and May 11.( 4) High frequency components were increased in the distortion process in May 1 to 3,5,7,and 9 to 12,caused by slow earthquakes before the Wenchuan earthquake according to wavelet analysis. The abnormal phenomena are summarized and the mechanics discussed in this paper. Strain solid tide distortions in body strain observations,the continuous repeated extensional and compressional abrupt changes accompanying these distortions,and the increase of high frequency components can be regarded as the index of short term and impending earthquake prediction,based on analysis of interference factors such as air pressure and water level.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10772026, 11072030)the Ph.D. Programs Foundation of Ministry of Education of China (Grant No. 20080070011)+1 种基金the Scientific Research Foundation of Ministry of Education of China for Returned Scholars (Grant No. 20080732040)the Program of Beijing Municipal Key Discipline Construction
文摘In this paper, the chaotic dynamics in an attitude transition maneuver of a slosh-spacecraft coupled with flexible appendage in going from minor axis to major axis spin under the influence of dissipative effects due to fuel slosh and a small flexible appendage constrained to only torsional vibration is investigated. The slosh-spacecraft coupled with flexible appendage in attitude maneuver carrying a sloshing liquid is considered as multi-body system with the sloshing motion modeled as a spherical pendulum. The focus in this paper is that the dynamics of the liquid and flexible appendage vibration are coupled. The equations of motion are derived and transformed into a form suitable for the application of Melnikov’s method. Melnikov’s integral is used to predict the transversal intersections of the stable and unstable manifolds for the perturbed system. An analytical criterion for chaotic motion is derived in terms of system parameters. This criterion is evaluated for its significance to the design of spacecraft. The dependence of the onset of chaos on quantities such as body shape and magnitude of damping values, fuel fraction and torsional vibration frequency of flexible appendage are investigated. In addition, we show that a spacecraft carrying a sloshing liquid, after passive reorientation maneuver, will end up with periodic limit motion other than a final major axis spin because of the intrinsic non-linearity of fuel slosh. Furthermore, an extensive numerical simulation is carried out to validate the Melnikov’s analytical result.
基金supported by the National Natural Science Foundation of China(Grant No.61471338)the Knowledge Innovation Program of the Chinese Academy of Sciences,Youth Innovation Promotion Association CAS,President Fund of UCASCRSRI Open Research Program(Grant No.CKWV2015217/KY)
文摘The three-dimensional discontinuous deformation analysis(3D-DDA) is a promising numerical method for both static and dynamic analyses of rock systems. Lacking mature software, its popularity is far behind its ability. To address this problem, this paper presents a new software architecture from a software engineering viewpoint. Based on 3D-DDA characteristics, the implementation of the proposed architecture has the following merits. Firstly, the software architecture separates data, computing, visualization, and signal control into individual modules. Secondly, data storage and parallel access are fully considered for different conditions. Thirdly, an open computing framework is provided which supports most numerical computing methods; common tools for equation solving and parallel computing are provided for further development. Fourthly, efficient visualization functions are provided by integrating a variety of visualization algorithms. A user-friendly graphical user interface is designed to improve the user experience. Finally, through a set of examples, the software is verified against both analytical solutions and the original code by Dr. Shi Gen Hua.
基金supported by the TIN2009-09492 project of the Spanish Ministry of Science and InnovationExcellence project TIC-6064 of Junta de Andalucia co-financed by FEDER funds
文摘In order to address the study of complex systems,the detection of patterns in their dynamics could play a key role in understanding their evolution.In particular,global patterns are required to detect emergent concepts and trends,some of them of a qualitative nature.Formal concept analysis(FCA) is a theory whose goal is to discover and extract knowledge from qualitative data(organized in concept lattices).In complex environments,such as sport competitions,the large amount of information currently available turns concept lattices into complex networks.The authors analyze how to apply FCA reasoning in order to increase confidence in sports predictions by means of detecting regularities from data through the management of intuitive and natural attributes extracted from publicly available information.The complexity of concept lattices-considered as networks with complex topological structure- is analyzed.It is applied to building a knowledge based system for confidence-based reasoning,which simulates how humans tend to avoid the complexity of concept networks by means of bounded reasoning skills.
文摘The pulsatile flow of blood in a tapered narrow artery with overlapping time-dependent stenosis is mathematically analyzed, modeling blood as Caxreau fluid. Perturbation method is employed for solving the resulting nonlinear system of equations along with the appropriate boundary conditions. The analytic solutions to the pressure gradient, velocity distribution, flow rate, wall shear stress and longitudinal impedance to flow axe obtained in the asymptotic form. The variation of the aforesaid flow quantities with respect to various physical parameters such as maximum depth of the stenosis, angle of tapering of the artery, power law index, Reynolds number, pulsatile amplitude of the flow and Weissenberg number is investigated. It is found that the wall shear stress and longitudinal impedance to flow increase with the increase of the angle of tapering of the artery, the maximum depth of the stenosis and pulsatile Reynolds number and these decrease with the increase of the amplitude of the flow, power law index and Weis- senberg number. The mean velocity of blood decreases significantly with the increase of the artery radius, maximum depth of the stenosis, angle of tapering of the artery.