Functionalizing and patterning of the silicon surface can be realized simultaneously by the chemomechanical method. The oxide-coated crystalline silicon (100) surface is scratched with a diamond tool in the presence...Functionalizing and patterning of the silicon surface can be realized simultaneously by the chemomechanical method. The oxide-coated crystalline silicon (100) surface is scratched with a diamond tool in the presence of aryldiazonium salt (C6H5N2BF4). Scratching activates the silicon surface by removing the passivation oxide layer to expose fresh Si atoms. The sur- face morphologies before and after chemomechanical reaction are characterized with atomic force microscopy. Time-of-flight secondary ion mass spectroscopy confirms the presence of C6H5 and provides evidence for the formation of self-assembled monolayer (SAM) on silicon surface via Si-C covalent bonds by scratching the silicon in the presence of C6H5N2BF4. C6H5 groups further bond with surface Si atoms via Si-C covalent bonds as confirmed from infrared spectroscopy results. We propose that chemomechanical reaction, which occurred during scratching the silicon surface, produce C6H5 groups from aryldiazonium salt. The relevant adhesion of SAM is measured. It is found that SAM can reduce the adhesion of silicon. The monolayer can be used as anti-adhesion monolayer for micro/nanoelectromechanical systems components under different environments and operating conditions.展开更多
In order to solve the dynamic reconstruction and local updating problem of three-dimensional geological solids, topology reasoning is used for three-dimensional geological modeling. This can advance the level of the c...In order to solve the dynamic reconstruction and local updating problem of three-dimensional geological solids, topology reasoning is used for three-dimensional geological modeling. This can advance the level of the corresponding section automation in implementing the 3D geological solid dynamical reconstruction by the construction of and reasoning on topology on the 3D curved surface. This method has been successfully used in the Nanjing city geological modeling and the Zijin gold mine modeling. The results prove that this method adapts to coplanar section and noncoplanar section data, and improves the efficiency of 3D geological modeling.展开更多
We studied the normality conditions in families of meromorphic functions, improved the results of Fang and Zalcman [Fang ML, Zalcman L, Normal families and shared values of meromorphic functions, Computational Methods...We studied the normality conditions in families of meromorphic functions, improved the results of Fang and Zalcman [Fang ML, Zalcman L, Normal families and shared values of meromorphic functions, Computational Methods and Function Theory, 2001, 1 (1): 289-299], and generalized two new normality criterions. Let F be a family of meromorphic functions in a domain D, a a non-zero finite complex number, B a positive real number, and k and m two positive integers satisfying m〉2k+4. If every function denoted by f belonging to F has only zeros with multiplicity at least k and satisfies f^m(z)f^(k)(Z)=α→ |^f(k)(z)| ≤B or f^m(z)f^(k)(z)=α→|f(z)| ≥, then F is normal in D.展开更多
Beckmann rearrangement mechanism of cyclohexanone oxime, based on the characteristic of self-catalyzed reaction and polymorphism was proposed. According to the suggested mechanism, the basic approach was the rearrange...Beckmann rearrangement mechanism of cyclohexanone oxime, based on the characteristic of self-catalyzed reaction and polymorphism was proposed. According to the suggested mechanism, the basic approach was the rearrangement of OXH+ while the SO3 acts as dehydrating agent and OXSO3 can turn to CPLSO3 ultimately. Considering self-catalyzed reaction between OXSO3 and CPLH+, kinetic model for Beckmann rearrangement was established. Corresponding parameters were estimated by using float genetic algorithm (GA) and simulation results agree well with the experimental data below -19.3℃. Industrial equipment was simulated and analyzed. Effects of key process parameters such as molar ratio of sulfuric acid to oxime and circulation ratio on the residual oxime are also discussed. The results show that the caprolactam exists as CPLH+ finally in oleum and the minimum molecular ratio of sulfuric acid to oxime can be 0.5 theoretically.展开更多
The action between imidazolinyl-quaternary-ammonium-salt(IQAS) molecule and Fe atom was studied, and the influence of the alkyl group connected with N atom of imidazoline ring on corrosion inhibition efficiency was ex...The action between imidazolinyl-quaternary-ammonium-salt(IQAS) molecule and Fe atom was studied, and the influence of the alkyl group connected with N atom of imidazoline ring on corrosion inhibition efficiency was explored. Quantum chemical methods, HF/6-31 G and HF/Lan L2 dz, were applied successively to calculate the parameters such as front molecular orbit energy of IQASⅠ-Ⅳ and chemical adsorption for IQASⅠ-Ⅳ and Fe atom. The corrosion inhibition efficiency was measured with the weight loss method of carbon steel samples in acidic solution and oil field sewage. Based on the theoretical analyses and experimental results, it is concluded that N-Fe coordination bond is formed between IQAS molecule and Fe atom, corrosion inhibition efficiency is decreased in the following order(from large to small): IQAS Ⅳ, IQAS Ⅲ, IQAS Ⅱ, IQASⅠ.展开更多
We investigate the gravitational time delay of light in the Schwarzschild black hole space-time surroundedby quintessence.With the analysis and numerical methods,we find that the gravitational time delay of light in t...We investigate the gravitational time delay of light in the Schwarzschild black hole space-time surroundedby quintessence.With the analysis and numerical methods,we find that the gravitational time delay of light in theSchwarzschild black hole space-time surrounded by quintessence increases when the normalization factor c increases,andthat the gravitational time delay also decreases when the quintessential state parameter ω_q increases.展开更多
The problem caused by shortness or excessiveness of snapshots and by coherent sources in underwater acoustic positioning is considered.A matched field localization algorithm based on CS-MUSIC(Compressive Sensing Multi...The problem caused by shortness or excessiveness of snapshots and by coherent sources in underwater acoustic positioning is considered.A matched field localization algorithm based on CS-MUSIC(Compressive Sensing Multiple Signal Classification) is proposed based on the sparse mathematical model of the underwater positioning.The signal matrix is calculated through the SVD(Singular Value Decomposition) of the observation matrix.The observation matrix in the sparse mathematical model is replaced by the signal matrix,and a new concise sparse mathematical model is obtained,which means not only the scale of the localization problem but also the noise level is reduced;then the new sparse mathematical model is solved by the CS-MUSIC algorithm which is a combination of CS(Compressive Sensing) method and MUSIC(Multiple Signal Classification) method.The algorithm proposed in this paper can overcome effectively the difficulties caused by correlated sources and shortness of snapshots,and it can also reduce the time complexity and noise level of the localization problem by using the SVD of the observation matrix when the number of snapshots is large,which will be proved in this paper.展开更多
We illustrate via the sunset diagram that dimensional regularization 'deforms' the nonlocal contents of multi-loop diagrams with its equivalence to cutoff regularization scheme recovered only after sub-diverge...We illustrate via the sunset diagram that dimensional regularization 'deforms' the nonlocal contents of multi-loop diagrams with its equivalence to cutoff regularization scheme recovered only after sub-divergence was subtracted. Then we employed a differential equation approach for calculating loop diagrams to verify that dimensional regularization deforms the 'low energy' contents before subtraction. The virtues of the differential equation approach are argued especially in nonperturbative perspective.展开更多
We start from a realistic half space then use to develop a mathematical asymptotic model for thermal imaging, which we analysis well suited for the design of reconstruction algorithms. We seek to reconstruct thermal a...We start from a realistic half space then use to develop a mathematical asymptotic model for thermal imaging, which we analysis well suited for the design of reconstruction algorithms. We seek to reconstruct thermal anomalies only through their rough features. With this way our proposed algorithms are stable against measurement noise and geometry perturbations. Based on rigorous asymptotic estimates, we first obtain an approximation for the temperature profile which we then use to design noniterative detection algorithms. We show on numerical simulations evidence that they are accurate and robust. Moreover, we provide a mathematical model for ultrasonic temperature imaging, which is an important technique in cancerous tissue ablation therapy.展开更多
As is generally known, Newton's notion of universal gravitation surpassed various theories of particular gravities in the early modem age, as represented mainly by Kepler and Hooke. In his seminal work Hooke and the ...As is generally known, Newton's notion of universal gravitation surpassed various theories of particular gravities in the early modem age, as represented mainly by Kepler and Hooke. In his seminal work Hooke and the Law of Universal Gravitation: A Reappraisal of a Reappraisal Richard S. Westfall argues that Hooke could not reach beyond the concept of spatially bounded particular gravities, as he deployed the method of analogy between the material principle of congruity and incongruity and the extension of gravitational spheres and their action at a distance. However, the doctrine of universal gravitation does not exclude the nature of particular gravities; it is predicated on the notion of an infinite expansion of individual-gravitational spheres and their uniform nature, namely the mutual and centripetal attraction. In my treatise 1 attempt to reinvestigate the nature and structure of gravitation, as established historically in the framework of Newtonian Classical Mechanics, by a method of structural intuition. It examines how the structural intuition, as represented in the celestial-mechanical intuitions of Hooke and Kepler, could unfold into an innovative process within the context of early modem mechanical philosophy, attaining thus a historical siglaificance and legitimacy as against the prevailing Newtonian method of geometric-mathematical axiomatization of mechanical principles. It also explores the actual demonstrative features of the tidal phenomenon with regard to its lunar- and solar-gravitational causation, which has been considered to date to be an important piece of empirical evidence for the theory of universal gravitation.展开更多
A new method for identifying nonlinear time varying systems with unknown structure is presented. The method extends the application area of basis sequence identification. The essential idea is to utilize the learning ...A new method for identifying nonlinear time varying systems with unknown structure is presented. The method extends the application area of basis sequence identification. The essential idea is to utilize the learning and nonlinear approximating ability of neural networks to model the non linearity of the system, characterize time varying dynamics of the system by the time varying parametric vector of the network, then the parametric vector of the network is approximated by a weighted sum of known basis sequences. Because of black box modeling ability of neural networks, the presented method can identify nonlinear time varying systems with unknown structure. In order to improve the real time capability of the algorithm, the neural network is trained by a simple fast learning algorithm based on local least squares presented by the authors. The effectiveness and the performance of the method are demonstrated by some simulation results.展开更多
The paper realizes the importance of communicating with schools to conduct nutritional screening, assessment and intervention programs for obesity and related risk factors to tackle the problem at earlier stage. The s...The paper realizes the importance of communicating with schools to conduct nutritional screening, assessment and intervention programs for obesity and related risk factors to tackle the problem at earlier stage. The screening program was conducted by dietetics' students "under supervision" as part of their practice and community services to apply some assessment method for mritional status. Two intermediate schools for girls in Jeddah city were involved in the screening stage, followed by a full nutritional assessment and implementation of a designed intervention program at one of the schools. At screening stage, interview questionnaires for diet histories and anthropometric measurements used to screen overweight status and related food patterns. National and international references data used for assessment and comparison. Following screening approach, a designed comprehensive nutritional assessment and intervention program was piloted at one of the screened schools for overweight status. For screening stage: the overall prevalence of overweight girls is 61% (n = 81 out of 133) of the population, 73% (n = 91) of girls were centrally obese. Almost 3/4 of all students reported no participations in any type of physical activities/exercises. Dietary behaviors included non-consumption of breakfast (83%) and low intake of fruit and vegetables (38%). For intervention stage, the present report concentrates on data concerning post intervention changes in Body Mass Index (BMI) and Waist Circumference (WC). By the 30 days of intervention there were significant changes in values for BMI according to Saudi growth chart (p value = 0.009) with no changes among the control group. No statistically significant difference in the mean WC of the group. Study's results suggest that approaching young girls through schools to screen, assess and intervene overweight status and risk factors is vital. Although the non-random selection of only two schools for screening the prevalence of overweight status among school girls prevent the geralizability of the study findings to wider population, previous studies used random selection of schools and large sample sizes showed a high prevalence of overweight status among Saudi students Therefore, designing and piloting of an intervention program for implementation at a national level is useful to tackle theproblem.展开更多
The electronic state and potential data of U2 molecules are performed by first principle calculations with B3LYP hybrid exchange-correlation functional, the valence electrons of U atom are treated with the (5s4p3d4f...The electronic state and potential data of U2 molecules are performed by first principle calculations with B3LYP hybrid exchange-correlation functional, the valence electrons of U atom are treated with the (5s4p3d4f)/[3s3p2d2f] contraction basis sets, and the cores are approximated with the relativistic effective core potential. The results show that the ground electronic state is x^9∑g+. The pair potential data are fitted with a Murrell-Sorbie analytical potential function. The U-U embedded atom method (EAM) interatomic potential is determined based on the generalized gradient approximation calculation within the framework of the density functional theory using Perdew-Burke-Ernzerhof exchange-correlation functional at the spin-polarized level. The physical properties, such as the cohesive energy, the lattice constant, the bulk modulus, the shear modulus, the sc/fec relative energy, the hep/fce rela- tive energy, the shear modulus and the monovacaney formation energy are used to evaluate the EAM potential parameters. The U-U pair potential determined by the first principle calculations is in agreement with that defined by the EAM potential parameters. The EAM calculated formation energy of the monovacancy in the fee structure is also found to be in close agreement with DFT calculation.展开更多
Objective: To systematically analyze and summarize non-thyrogenous masses of the neck (NTMN) by consideration of new areas, a large sample size and multiple-aspect analysis. Methods: Our research involved 3125 NTM...Objective: To systematically analyze and summarize non-thyrogenous masses of the neck (NTMN) by consideration of new areas, a large sample size and multiple-aspect analysis. Methods: Our research involved 3125 NTMN cases. We summarized the proportion of various NTMN and the distribution of the neck diseases based on the new international classification. The clinical traits such as sexual proportion and age, etc, were analyzed along with the unknown primary cervical metastatic carcinomas (UPCMC), and built up a mathematical model based on the data above. Results: There were 68 different diseases identified. Among all the NTMN, the percentage of metastatic carcinomas was 63.3%. The neck masses with a focus above the clavicle comprised 62.3% of the metastatic carcinomas whose focuses were clear. Moreover, other results almost supported the "rule of 80%". There was an obvious distribution of traits at every sub level. For example, there were 23 different diseases in level Ⅲ, of which the most common was lymphoma. UPCMC made up 12.3% of all metastatic carcinomas. The clinic cases could be analyzed by our model even to form a primary diagnosis which showed a high coincident rate with clinic diagnosis. Conclusion: NTMN are complex and various, with a definite distribution in each neck level. Data relating component character, sex ratio and UPCMC et al to the clinical traits of NTMN will provide vigorous support for clinical applications. The mathematical model could be an efficient method to synthetically analyze complicate data of NTMN.展开更多
Objective To evaluate the clinical outcomes of surgical therapy in treating traumatic instability of subaxial cervical spine through either anterior or posterior approach. Methods According to the Allen-Fergurson'...Objective To evaluate the clinical outcomes of surgical therapy in treating traumatic instability of subaxial cervical spine through either anterior or posterior approach. Methods According to the Allen-Fergurson's classification, we retrospectively studied 42 cases of traumatic instability of subaxial cervical spine through either anterior or posterior surgical reconstruction. Patients requiring approach for either reduction or decompression were not included. Results The average follow-up interval was 3 years and 2 months. The anterior and posterior reconstructions were 24 and 18 cases, respectively. Before operation, the average scores of JOA and VAS were: 12.1 and 6.9 for anterior group, and 12.3 and 7.2 for posterior group. At the final assement, the scores of JOA and VAS improved to 16.0 and 2.2 for anterior group, and 15.7 and 2.6 for posterior group. The average ASIA motor scores of anterior and posterior group improved to 68.2 and 65.5 at the final follow-up from 58.4 and 59.7 before operation, respectively. The ASIA grade (A-E) was converted to a numeric score. The average scores before operation in the anterior and posterior group were 3.3 and 3.4, and increased to 3.8 and 3.7 at the final follow-up. After operation, there were different extent improvements of average radiological parameter, such as Cobb angle, vertebral body translation and disc height ratio. The average operation time and blood losing were 122 min and 125 mL for anterior group, and 153 min and 287 mL for posterior group. Fusion was achieved in all patients and 4 and 2 complications occurred at the anterior or posterior group. Conclusion The results showed that there were no obvious difference in parameters, such as neurological assements, functional grades, fusion rate, operation time and blood losing, between anterior and posterior group, except the virtues of anterior group in reconstruction and maintaining physiologic cervical lordosis and intervertrbal disc height occurred.展开更多
In the present paper, we study effect of the long-range Coulomb interaction on the thermodynamic propertiesof graphene by renormalization group methods.Our calculations show that both the specific heat and the magneti...In the present paper, we study effect of the long-range Coulomb interaction on the thermodynamic propertiesof graphene by renormalization group methods.Our calculations show that both the specific heat and the magneticsusceptibility of the material behave differently from the Landau Fermi liquid.More precisely, we find that thesequantities are logarithmically suppressed with respect to its noninteracting counterpart when temperature is low.展开更多
A detailed mathematical model of a direct internal reforming solid oxide fuel cell(DIR-SOFC) incorporating with simulation of chemical and physical processes in the fuel cell is presented. The model is developed based...A detailed mathematical model of a direct internal reforming solid oxide fuel cell(DIR-SOFC) incorporating with simulation of chemical and physical processes in the fuel cell is presented. The model is developed based on the reforming and electrochemical reaction mechanisms,mass and energy conservation,and heat transfer. A computational fluid dynamics(CFD) method is used for solving the complicated multiple partial differential equations(PDEs) to obtain the numerical approximations. The resulting distributions of chemical species concentrations,temperature and current density in a cross-flow DIR-SOFC are given and analyzed in detail. Further,the influence between distributions of chemical species concentrations,temperature and current density during the simulation is illustrated and discussed. The heat and mass transfer,and the kinetics of reforming and electrochemical reactions have significant effects on the parameter distributions within the cell. The results show the particular characteristics of the DIR-SOFC among fuel cells,and can aid in stack design and control.展开更多
A finite volume algorithm was established in order to investigate two-dimensional hydrodynamic problems. These include viscous free surface flow interaction with free rigid bodies in the case of large and/or relative ...A finite volume algorithm was established in order to investigate two-dimensional hydrodynamic problems. These include viscous free surface flow interaction with free rigid bodies in the case of large and/or relative motions. Two-phase flow with complex deformations at the interface was simulated using a fractional step-volume of fluid algorithm. In addition, body motions were captured by an overlapping mesh system. Here, flow variables are transferred using a simple fully implicit non-conservative interpolation scheme which maintains the second-order accuracy of implemented spatial discretisation. Code was developed and an appropriate set of problems investigated. Results show good potential for development of a virtual hydrodynamics laboratory.展开更多
Embodied cognition is an approach to cognition that departs from traditional Descartes’ mind-body dualism for its emphasis on bodily interactions with the environment. The paper firstly describes three distinctive fe...Embodied cognition is an approach to cognition that departs from traditional Descartes’ mind-body dualism for its emphasis on bodily interactions with the environment. The paper firstly describes three distinctive features of embodied cognition. Furthermore, from the perspective of philosophical methodology, the paper outlines Vygotsky’s socio-cultural theory and his contributions to the development of cognitive science. Three basic themes of Vygotsky’s writings are specifically described: genetic forces as a foundation of the study of mind, social origin of higher mental functioning, and mediation of sign systems in inter-mental and intra-mental functioning. Against the background of Vygotsky’s sociocultural theory, we further discuss the interface between embodied cognition and Vygotsky’s socio-cultural theory. It is claimed that bodily states and body-environment interactions are closely connected to sense-making. Embodied cognition should emphasize on the unity of body, mind, and cultural environment. Finally, the paper concludes with the influence of sociocultural theory on the study of embodied cognition.展开更多
基金We thank Prof. Yang Gan of Harbin Institute of Technology, and Prof. Fu-long Yuan of Heilongjiang University for the help in the experiments. This work was supported by the Center for Precision Engineering of Harbin Institute of Technology, the Youth the Colleges and Universities in Heilongjiang Province in 2010 (No.1155G54), the Training Fund Project of Jiamusi University (No.RC2009-037), and the National Natural Science Foundation of China (No.51105174).
文摘Functionalizing and patterning of the silicon surface can be realized simultaneously by the chemomechanical method. The oxide-coated crystalline silicon (100) surface is scratched with a diamond tool in the presence of aryldiazonium salt (C6H5N2BF4). Scratching activates the silicon surface by removing the passivation oxide layer to expose fresh Si atoms. The sur- face morphologies before and after chemomechanical reaction are characterized with atomic force microscopy. Time-of-flight secondary ion mass spectroscopy confirms the presence of C6H5 and provides evidence for the formation of self-assembled monolayer (SAM) on silicon surface via Si-C covalent bonds by scratching the silicon in the presence of C6H5N2BF4. C6H5 groups further bond with surface Si atoms via Si-C covalent bonds as confirmed from infrared spectroscopy results. We propose that chemomechanical reaction, which occurred during scratching the silicon surface, produce C6H5 groups from aryldiazonium salt. The relevant adhesion of SAM is measured. It is found that SAM can reduce the adhesion of silicon. The monolayer can be used as anti-adhesion monolayer for micro/nanoelectromechanical systems components under different environments and operating conditions.
基金the Research Foundation for Outstanding Young Teachers, China University of Geosciences.
文摘In order to solve the dynamic reconstruction and local updating problem of three-dimensional geological solids, topology reasoning is used for three-dimensional geological modeling. This can advance the level of the corresponding section automation in implementing the 3D geological solid dynamical reconstruction by the construction of and reasoning on topology on the 3D curved surface. This method has been successfully used in the Nanjing city geological modeling and the Zijin gold mine modeling. The results prove that this method adapts to coplanar section and noncoplanar section data, and improves the efficiency of 3D geological modeling.
文摘We studied the normality conditions in families of meromorphic functions, improved the results of Fang and Zalcman [Fang ML, Zalcman L, Normal families and shared values of meromorphic functions, Computational Methods and Function Theory, 2001, 1 (1): 289-299], and generalized two new normality criterions. Let F be a family of meromorphic functions in a domain D, a a non-zero finite complex number, B a positive real number, and k and m two positive integers satisfying m〉2k+4. If every function denoted by f belonging to F has only zeros with multiplicity at least k and satisfies f^m(z)f^(k)(Z)=α→ |^f(k)(z)| ≤B or f^m(z)f^(k)(z)=α→|f(z)| ≥, then F is normal in D.
基金Project(20233040) supported by the National Natural Science Foundation of China and SI NOPEC
文摘Beckmann rearrangement mechanism of cyclohexanone oxime, based on the characteristic of self-catalyzed reaction and polymorphism was proposed. According to the suggested mechanism, the basic approach was the rearrangement of OXH+ while the SO3 acts as dehydrating agent and OXSO3 can turn to CPLSO3 ultimately. Considering self-catalyzed reaction between OXSO3 and CPLH+, kinetic model for Beckmann rearrangement was established. Corresponding parameters were estimated by using float genetic algorithm (GA) and simulation results agree well with the experimental data below -19.3℃. Industrial equipment was simulated and analyzed. Effects of key process parameters such as molar ratio of sulfuric acid to oxime and circulation ratio on the residual oxime are also discussed. The results show that the caprolactam exists as CPLH+ finally in oleum and the minimum molecular ratio of sulfuric acid to oxime can be 0.5 theoretically.
基金Project (05A002) supported by Scientific Research Fundation of Hunan Provincial Education Depart ment project(04JJY40010) supported by the Natural Science Foundation of Hunan Province
文摘The action between imidazolinyl-quaternary-ammonium-salt(IQAS) molecule and Fe atom was studied, and the influence of the alkyl group connected with N atom of imidazoline ring on corrosion inhibition efficiency was explored. Quantum chemical methods, HF/6-31 G and HF/Lan L2 dz, were applied successively to calculate the parameters such as front molecular orbit energy of IQASⅠ-Ⅳ and chemical adsorption for IQASⅠ-Ⅳ and Fe atom. The corrosion inhibition efficiency was measured with the weight loss method of carbon steel samples in acidic solution and oil field sewage. Based on the theoretical analyses and experimental results, it is concluded that N-Fe coordination bond is formed between IQAS molecule and Fe atom, corrosion inhibition efficiency is decreased in the following order(from large to small): IQAS Ⅳ, IQAS Ⅲ, IQAS Ⅱ, IQASⅠ.
基金the State Key Basic Research Program of China under Grant No.2003CB716300National Natural Science Foundation of China under Grant No.10547114Scientific Research Fund of Hunan Normal University
文摘We investigate the gravitational time delay of light in the Schwarzschild black hole space-time surroundedby quintessence.With the analysis and numerical methods,we find that the gravitational time delay of light in theSchwarzschild black hole space-time surrounded by quintessence increases when the normalization factor c increases,andthat the gravitational time delay also decreases when the quintessential state parameter ω_q increases.
基金supported by the National Natural Science Foundation of China (61202208)
文摘The problem caused by shortness or excessiveness of snapshots and by coherent sources in underwater acoustic positioning is considered.A matched field localization algorithm based on CS-MUSIC(Compressive Sensing Multiple Signal Classification) is proposed based on the sparse mathematical model of the underwater positioning.The signal matrix is calculated through the SVD(Singular Value Decomposition) of the observation matrix.The observation matrix in the sparse mathematical model is replaced by the signal matrix,and a new concise sparse mathematical model is obtained,which means not only the scale of the localization problem but also the noise level is reduced;then the new sparse mathematical model is solved by the CS-MUSIC algorithm which is a combination of CS(Compressive Sensing) method and MUSIC(Multiple Signal Classification) method.The algorithm proposed in this paper can overcome effectively the difficulties caused by correlated sources and shortness of snapshots,and it can also reduce the time complexity and noise level of the localization problem by using the SVD of the observation matrix when the number of snapshots is large,which will be proved in this paper.
文摘We illustrate via the sunset diagram that dimensional regularization 'deforms' the nonlocal contents of multi-loop diagrams with its equivalence to cutoff regularization scheme recovered only after sub-divergence was subtracted. Then we employed a differential equation approach for calculating loop diagrams to verify that dimensional regularization deforms the 'low energy' contents before subtraction. The virtues of the differential equation approach are argued especially in nonperturbative perspective.
基金supported by the ANR project EchoScan(AN-06-Blan-0089)the NSF grant DMS 0707421.
文摘We start from a realistic half space then use to develop a mathematical asymptotic model for thermal imaging, which we analysis well suited for the design of reconstruction algorithms. We seek to reconstruct thermal anomalies only through their rough features. With this way our proposed algorithms are stable against measurement noise and geometry perturbations. Based on rigorous asymptotic estimates, we first obtain an approximation for the temperature profile which we then use to design noniterative detection algorithms. We show on numerical simulations evidence that they are accurate and robust. Moreover, we provide a mathematical model for ultrasonic temperature imaging, which is an important technique in cancerous tissue ablation therapy.
文摘As is generally known, Newton's notion of universal gravitation surpassed various theories of particular gravities in the early modem age, as represented mainly by Kepler and Hooke. In his seminal work Hooke and the Law of Universal Gravitation: A Reappraisal of a Reappraisal Richard S. Westfall argues that Hooke could not reach beyond the concept of spatially bounded particular gravities, as he deployed the method of analogy between the material principle of congruity and incongruity and the extension of gravitational spheres and their action at a distance. However, the doctrine of universal gravitation does not exclude the nature of particular gravities; it is predicated on the notion of an infinite expansion of individual-gravitational spheres and their uniform nature, namely the mutual and centripetal attraction. In my treatise 1 attempt to reinvestigate the nature and structure of gravitation, as established historically in the framework of Newtonian Classical Mechanics, by a method of structural intuition. It examines how the structural intuition, as represented in the celestial-mechanical intuitions of Hooke and Kepler, could unfold into an innovative process within the context of early modem mechanical philosophy, attaining thus a historical siglaificance and legitimacy as against the prevailing Newtonian method of geometric-mathematical axiomatization of mechanical principles. It also explores the actual demonstrative features of the tidal phenomenon with regard to its lunar- and solar-gravitational causation, which has been considered to date to be an important piece of empirical evidence for the theory of universal gravitation.
文摘A new method for identifying nonlinear time varying systems with unknown structure is presented. The method extends the application area of basis sequence identification. The essential idea is to utilize the learning and nonlinear approximating ability of neural networks to model the non linearity of the system, characterize time varying dynamics of the system by the time varying parametric vector of the network, then the parametric vector of the network is approximated by a weighted sum of known basis sequences. Because of black box modeling ability of neural networks, the presented method can identify nonlinear time varying systems with unknown structure. In order to improve the real time capability of the algorithm, the neural network is trained by a simple fast learning algorithm based on local least squares presented by the authors. The effectiveness and the performance of the method are demonstrated by some simulation results.
文摘The paper realizes the importance of communicating with schools to conduct nutritional screening, assessment and intervention programs for obesity and related risk factors to tackle the problem at earlier stage. The screening program was conducted by dietetics' students "under supervision" as part of their practice and community services to apply some assessment method for mritional status. Two intermediate schools for girls in Jeddah city were involved in the screening stage, followed by a full nutritional assessment and implementation of a designed intervention program at one of the schools. At screening stage, interview questionnaires for diet histories and anthropometric measurements used to screen overweight status and related food patterns. National and international references data used for assessment and comparison. Following screening approach, a designed comprehensive nutritional assessment and intervention program was piloted at one of the screened schools for overweight status. For screening stage: the overall prevalence of overweight girls is 61% (n = 81 out of 133) of the population, 73% (n = 91) of girls were centrally obese. Almost 3/4 of all students reported no participations in any type of physical activities/exercises. Dietary behaviors included non-consumption of breakfast (83%) and low intake of fruit and vegetables (38%). For intervention stage, the present report concentrates on data concerning post intervention changes in Body Mass Index (BMI) and Waist Circumference (WC). By the 30 days of intervention there were significant changes in values for BMI according to Saudi growth chart (p value = 0.009) with no changes among the control group. No statistically significant difference in the mean WC of the group. Study's results suggest that approaching young girls through schools to screen, assess and intervene overweight status and risk factors is vital. Although the non-random selection of only two schools for screening the prevalence of overweight status among school girls prevent the geralizability of the study findings to wider population, previous studies used random selection of schools and large sample sizes showed a high prevalence of overweight status among Saudi students Therefore, designing and piloting of an intervention program for implementation at a national level is useful to tackle theproblem.
文摘The electronic state and potential data of U2 molecules are performed by first principle calculations with B3LYP hybrid exchange-correlation functional, the valence electrons of U atom are treated with the (5s4p3d4f)/[3s3p2d2f] contraction basis sets, and the cores are approximated with the relativistic effective core potential. The results show that the ground electronic state is x^9∑g+. The pair potential data are fitted with a Murrell-Sorbie analytical potential function. The U-U embedded atom method (EAM) interatomic potential is determined based on the generalized gradient approximation calculation within the framework of the density functional theory using Perdew-Burke-Ernzerhof exchange-correlation functional at the spin-polarized level. The physical properties, such as the cohesive energy, the lattice constant, the bulk modulus, the shear modulus, the sc/fec relative energy, the hep/fce rela- tive energy, the shear modulus and the monovacaney formation energy are used to evaluate the EAM potential parameters. The U-U pair potential determined by the first principle calculations is in agreement with that defined by the EAM potential parameters. The EAM calculated formation energy of the monovacancy in the fee structure is also found to be in close agreement with DFT calculation.
文摘Objective: To systematically analyze and summarize non-thyrogenous masses of the neck (NTMN) by consideration of new areas, a large sample size and multiple-aspect analysis. Methods: Our research involved 3125 NTMN cases. We summarized the proportion of various NTMN and the distribution of the neck diseases based on the new international classification. The clinical traits such as sexual proportion and age, etc, were analyzed along with the unknown primary cervical metastatic carcinomas (UPCMC), and built up a mathematical model based on the data above. Results: There were 68 different diseases identified. Among all the NTMN, the percentage of metastatic carcinomas was 63.3%. The neck masses with a focus above the clavicle comprised 62.3% of the metastatic carcinomas whose focuses were clear. Moreover, other results almost supported the "rule of 80%". There was an obvious distribution of traits at every sub level. For example, there were 23 different diseases in level Ⅲ, of which the most common was lymphoma. UPCMC made up 12.3% of all metastatic carcinomas. The clinic cases could be analyzed by our model even to form a primary diagnosis which showed a high coincident rate with clinic diagnosis. Conclusion: NTMN are complex and various, with a definite distribution in each neck level. Data relating component character, sex ratio and UPCMC et al to the clinical traits of NTMN will provide vigorous support for clinical applications. The mathematical model could be an efficient method to synthetically analyze complicate data of NTMN.
文摘Objective To evaluate the clinical outcomes of surgical therapy in treating traumatic instability of subaxial cervical spine through either anterior or posterior approach. Methods According to the Allen-Fergurson's classification, we retrospectively studied 42 cases of traumatic instability of subaxial cervical spine through either anterior or posterior surgical reconstruction. Patients requiring approach for either reduction or decompression were not included. Results The average follow-up interval was 3 years and 2 months. The anterior and posterior reconstructions were 24 and 18 cases, respectively. Before operation, the average scores of JOA and VAS were: 12.1 and 6.9 for anterior group, and 12.3 and 7.2 for posterior group. At the final assement, the scores of JOA and VAS improved to 16.0 and 2.2 for anterior group, and 15.7 and 2.6 for posterior group. The average ASIA motor scores of anterior and posterior group improved to 68.2 and 65.5 at the final follow-up from 58.4 and 59.7 before operation, respectively. The ASIA grade (A-E) was converted to a numeric score. The average scores before operation in the anterior and posterior group were 3.3 and 3.4, and increased to 3.8 and 3.7 at the final follow-up. After operation, there were different extent improvements of average radiological parameter, such as Cobb angle, vertebral body translation and disc height ratio. The average operation time and blood losing were 122 min and 125 mL for anterior group, and 153 min and 287 mL for posterior group. Fusion was achieved in all patients and 4 and 2 complications occurred at the anterior or posterior group. Conclusion The results showed that there were no obvious difference in parameters, such as neurological assements, functional grades, fusion rate, operation time and blood losing, between anterior and posterior group, except the virtues of anterior group in reconstruction and maintaining physiologic cervical lordosis and intervertrbal disc height occurred.
基金Supported by the Chinese National Science Foundation under Grant No.10874003 by Ministry of Science and Technology of China under Grant No.2006CB921300
文摘In the present paper, we study effect of the long-range Coulomb interaction on the thermodynamic propertiesof graphene by renormalization group methods.Our calculations show that both the specific heat and the magneticsusceptibility of the material behave differently from the Landau Fermi liquid.More precisely, we find that thesequantities are logarithmically suppressed with respect to its noninteracting counterpart when temperature is low.
基金Project (No. 2006AA05Z148) supported by the Hi-Tech Research and Development Program (863) of China
文摘A detailed mathematical model of a direct internal reforming solid oxide fuel cell(DIR-SOFC) incorporating with simulation of chemical and physical processes in the fuel cell is presented. The model is developed based on the reforming and electrochemical reaction mechanisms,mass and energy conservation,and heat transfer. A computational fluid dynamics(CFD) method is used for solving the complicated multiple partial differential equations(PDEs) to obtain the numerical approximations. The resulting distributions of chemical species concentrations,temperature and current density in a cross-flow DIR-SOFC are given and analyzed in detail. Further,the influence between distributions of chemical species concentrations,temperature and current density during the simulation is illustrated and discussed. The heat and mass transfer,and the kinetics of reforming and electrochemical reactions have significant effects on the parameter distributions within the cell. The results show the particular characteristics of the DIR-SOFC among fuel cells,and can aid in stack design and control.
文摘A finite volume algorithm was established in order to investigate two-dimensional hydrodynamic problems. These include viscous free surface flow interaction with free rigid bodies in the case of large and/or relative motions. Two-phase flow with complex deformations at the interface was simulated using a fractional step-volume of fluid algorithm. In addition, body motions were captured by an overlapping mesh system. Here, flow variables are transferred using a simple fully implicit non-conservative interpolation scheme which maintains the second-order accuracy of implemented spatial discretisation. Code was developed and an appropriate set of problems investigated. Results show good potential for development of a virtual hydrodynamics laboratory.
文摘Embodied cognition is an approach to cognition that departs from traditional Descartes’ mind-body dualism for its emphasis on bodily interactions with the environment. The paper firstly describes three distinctive features of embodied cognition. Furthermore, from the perspective of philosophical methodology, the paper outlines Vygotsky’s socio-cultural theory and his contributions to the development of cognitive science. Three basic themes of Vygotsky’s writings are specifically described: genetic forces as a foundation of the study of mind, social origin of higher mental functioning, and mediation of sign systems in inter-mental and intra-mental functioning. Against the background of Vygotsky’s sociocultural theory, we further discuss the interface between embodied cognition and Vygotsky’s socio-cultural theory. It is claimed that bodily states and body-environment interactions are closely connected to sense-making. Embodied cognition should emphasize on the unity of body, mind, and cultural environment. Finally, the paper concludes with the influence of sociocultural theory on the study of embodied cognition.