The dimension lumber (45mm×90mm×3700mm) of plantation Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) was graded to four different classes as SS, No. 1, No.2 and No.3, according to national lumber ...The dimension lumber (45mm×90mm×3700mm) of plantation Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) was graded to four different classes as SS, No. 1, No.2 and No.3, according to national lumber grades authority (NLGA) for structure light framing and structure joists and planks. The properties of apparent density was determined at 15% moisture content, bending strength and stiffness were tested according to American Society for Testing and Materials (ASTM) D198-99, and dynamic modulus of elasticity (Eusw) was measured by ultrasonic technique, for predicting the flexural properties of different grade lumbers. The results showed that Eosw was larger than the static MOE. The relationship between Eusw and static MOE was significant at 0.01 level, and the determination coefficients (R2) of the four grade lumbers followed the sequence as R^2No.2 (0.616)〉 R^2ss (0.567)〉 R^2No1 (0.366)〉 R^2No.3 (0.137). The R^2 of Fusw and MOR were lower than that of the Etru and MOR for each grade. The Eusw of all the grade lumbers, except No.3-grade, had significant correlation with the static MOE and MOR, thus the bending strengthof those grade lumbers can be estimated by the E The Etru valuesof four grade lumbers followed a sequence as No.2-grade (10.701 GPa) 〉 SS-grade (10.359 GPa) 〉 No.l-grade (9.840 GPa) 〉 No.3-grade (9.554 GPa). For the same grade dimension lumber, its Eusw value was larger than static MOE. Mean values of MOR for four grade lumbers follow a sequence as No.2-grade (48.67 MPa) 〉 SS-grade (48.16 MPa) 〉 No.3-grade (46.55 MPa) 〉 No. 1-grade (43.39MPa).展开更多
Multivalent polymer chains exhibit excellent prospect in biomedical applications by serving as therapeutic agents. Using three-dimensional (3D) Langevin dynamics simulations, we investigate adsorption behaviors of m...Multivalent polymer chains exhibit excellent prospect in biomedical applications by serving as therapeutic agents. Using three-dimensional (3D) Langevin dynamics simulations, we investigate adsorption behaviors of multivalent polymer chains to a surface with receptors. Multivalent polymer chains display superselective adsorption. Furthermore, the range of density of surface receptors at which a multivalent polymer chain displays a superselective behavior, narrows down for chains with higher density of ligands. Meanwhile, the optimal density of surface receptors where the highest superselectivity is achieved, decreases with increasing the density of ligands. Then, the conformational properties of bound multivalent chains are studied systematically. Interestingly, we find that the equilibrium radius of gyration Rg and its horizontal component have a maximum as a function of the density of surface receptors. The scaling exponents of Rg with the length of chain suggest that with increasing the density of surface receptors., the conformations of a bound multivalent polymer chain first fall in between those of a two-dimensional (2D) and a 3D chain, while it is slightly collapsed subsequently.展开更多
In the minimal supersymmetric standard model with R-parity violation, the lepton number violating top quark interactions can contribute to the top pair production at a linear collider via tree-level u-channel squark e...In the minimal supersymmetric standard model with R-parity violation, the lepton number violating top quark interactions can contribute to the top pair production at a linear collider via tree-level u-channel squark exchange diagrams. We calculate such contributions and find that in the allowed range of these R-violating couplings, the top pair production rate as well as the top quark polarization and the forward-backward asymmetry can be significantly altered. By comparing the unpolarized beams with the polarized beams, we find that the polarized beams are more powerful in probing such new physics.展开更多
In this paper, two concepts of relative compactness-the relative strong fuzzy compactness and the relative ultra-fuzzy compactness are defined in L-topological spaces for an arbitrary L-set. Properties of relative str...In this paper, two concepts of relative compactness-the relative strong fuzzy compactness and the relative ultra-fuzzy compactness are defined in L-topological spaces for an arbitrary L-set. Properties of relative strong fuzzy sets and relative ultra-fuzzy compact sets are studied in detail and some characteristic theorems are given. Some examples are illustrated.展开更多
We discuss the anomalous magnetic moment of muon in the minimal supersymmetric model with and without right-handed neutrinos. In the same framework, the decay width of is also evaluated. Considering the measured val...We discuss the anomalous magnetic moment of muon in the minimal supersymmetric model with and without right-handed neutrinos. In the same framework, the decay width of is also evaluated. Considering the measured value of muon in the E821 experiment and other experimental constraints on the lepton-flavor-violation processes, we carry out numerical analysis on the concerned observables in the minimal supergravity scenario.展开更多
AIM:To investigate the diagnosis of nonalcoholic steatohepatitis(NASH) using contrast ultrasonography in the NASH rat model.METHODS:The liver in methionine choline-deficient diet(MCDD) rats,a NASH model constructed by...AIM:To investigate the diagnosis of nonalcoholic steatohepatitis(NASH) using contrast ultrasonography in the NASH rat model.METHODS:The liver in methionine choline-deficient diet(MCDD) rats,a NASH model constructed by feeding an MCDD,was examined by contrast ultrasonography at weeks 2,4,8,12 and 16,with late phase images of contrast ultrasonography(Kupffer imaging) in which contrast enhancement was achieved by incorporation of a contrast agent by Kupffer cells(KCs),and images were compared to those in rats taking a regular chow.RESULTS:Decrease in contrast enhancement was observed first in MCDD rats at week 2.KCs were counted based on immunohistochemistry,but their numbers were not reduced and it was assumed that attenuation of contrast enhancement was attributable to reduced phagocytic activity of the KCs.CONCLUSION:It is suggested that clinical application of contrast ultrasonography may be valuable for noninvasive diagnosis of NASH.展开更多
Using the "pseudo-invariant eigen-operator" method we find the energy-gap of the Jaynes-Cummings Hamiltonian model of an atom-cavity system. This model takes the atomic centre-of-mass motion into account. The supers...Using the "pseudo-invariant eigen-operator" method we find the energy-gap of the Jaynes-Cummings Hamiltonian model of an atom-cavity system. This model takes the atomic centre-of-mass motion into account. The supersymmetric structure is involved in the Hamiltonian of an atom-cavity system. By selecting suitable supersymmettic generators and using supersymmetrie transformation the Hamiltonian is diagonalized and energy eigenvectors are obtained.展开更多
We study the energy level statistics of the SO(5) limit of super-symmetry U(6/4) in odd-A nucleus using the interacting boson-fermion model. The nearest neighbor spacing distribution (NSD) and the spectral rigidity (...We study the energy level statistics of the SO(5) limit of super-symmetry U(6/4) in odd-A nucleus using the interacting boson-fermion model. The nearest neighbor spacing distribution (NSD) and the spectral rigidity (△3)are investigated, and the factors that affect the properties of level statistics are also discussed. The results show that the boson number N is a dominant factor. If N is small, both the interaction strengths of subgroups SOB(5) and SOBF(5)and the spin play important roles in the energy level statistics, however, along with the increase of N, the statistics distribution would tend to be in Poisson form.展开更多
Based on the drying-wetting cycles experiment and the carbonation-drying-wetting cycles experiment for coral aggregate seawater concrete(CASC)with different strength grades,the effects of carbonation-drying-wetting on...Based on the drying-wetting cycles experiment and the carbonation-drying-wetting cycles experiment for coral aggregate seawater concrete(CASC)with different strength grades,the effects of carbonation-drying-wetting on the durability of CASC are studied with the surface state,mass loss rate,relative dynamic elastic modulus,ultrasonic wave velocity and cube compressive strength as indices.Results show that the mass loss rate of CASC increases gradually with the increase in cycle times in the drying-wetting and carbonation-drying-wetting cycles.The mass loss rate increases relatively slowly at the initial stage but it increases remarkably after 10 cycles.The relative dynamic elastic modulus and ultrasonic wave velocity decrease gradually with the increase in cycle times.After 6 cycles,the decrease rate of the relative dynamic elastic modulus and ultrasonic wave velocity of CASC tends to be flat and the surface is slightly damaged.Compared with the initial 28 d cube compressive strength,the cube compressive strength of CASC decreases by 8.8%to 11.0%.Drying-wetting cycles and carbonation can accelerate seawater erosion on CASC,and drying-wetting cycles result in salting-out and accelerate the destruction of concrete.Therefore,the carbonation-drying-wetting accelerates the destruction of CASC.展开更多
In this paper we introduce bilocal fields in the global color symmetry model and consider color and electrical neutrality conditions simultaneously to study the effect of strange quark mass Ms for the momentum-depende...In this paper we introduce bilocal fields in the global color symmetry model and consider color and electrical neutrality conditions simultaneously to study the effect of strange quark mass Ms for the momentum-dependent condensate of color-flavor locked phase. Consequently we find that there will be a quantum phase transition occurring.展开更多
Objective To evaluate left atrial function in essential hypertension patients with different patterns of left ventricular geometric models by real-time three-dimensional echocardiography (RT-3DE) and left atrial tra...Objective To evaluate left atrial function in essential hypertension patients with different patterns of left ventricular geometric models by real-time three-dimensional echocardiography (RT-3DE) and left atrial tracking (EAT).展开更多
In this paper we theoretically report an unconventional quantum phase transition of a simple Lipkin- Meshkow-Glick model: an interacting collective spin system without external magnetic field. It is shown that this m...In this paper we theoretically report an unconventional quantum phase transition of a simple Lipkin- Meshkow-Glick model: an interacting collective spin system without external magnetic field. It is shown that this model with integer-spin can exhibit a flrst-order quantum phase transition between different disordered phases, and more intriguingly, possesses a hidden supersymmetry at the critical point. However, for half-integer spin we predict another flrst-order quantum phase transition between two different long-range-ordered phases with a vanishing energy gap, which is induced by the destructive topological quantum interference between the intanton and anti-instanton tunneling paths and accompanies spontaneously breaking of supersymmetry at the same critical point. We also show that, when the total spin-value varies from half-integer to integer this model can exhibit an abrupt variation of Berry phase from π to zero.展开更多
Objectives To establish a cost-effective and reproducible procedure for induction of chronic left ventricular aneurysm (LVA) in rabbits. Methods Acute myocardial infarction (AMI) was induced in 35 rabbits via conc...Objectives To establish a cost-effective and reproducible procedure for induction of chronic left ventricular aneurysm (LVA) in rabbits. Methods Acute myocardial infarction (AMI) was induced in 35 rabbits via concomitant ligation of the left anterior descending (LAD) coronary artery and the circumflex (Cx) branch at the middle portion. Development of AMI was co n-firmed by ST segment elevation and akinesis of the occluded area. Echocardiography, pathological evaluation, and agar i n-tra-chamber casting were utilized to validate the formation of LVA four weeks after the surgery. Left ventricular end systolic pressure (LVESP) and diastolic pressure (LVEDP) were measured before, immediately after and four weeks after ligation. D i-mensions of the ventricular chamber, thickness of the interventricular septum (IVS) and the left ventricular posterior wall (LVPW) left ventricular end diastolic volume (LVEDV) and systolic volume (LVESV), and ejection fraction (EF) were recorded by echo-cardiography. Results Thirty one (88.6%) rabbits survived myocardial infarction and 26 of them developed aneurysm (83.9%). The mean area of aneurysm was 33.4% ± 2.4% of the left ventricle. LVEF markedly decreased after LVA formation, whereas LVEDV, LVESV and the thickness of IVS as well as the dimension of ventricular chamber from apex to mitral valve annulus significantly increased. LVESP immediately dropped after ligation and recovered to a small extent after LVA formation. LVEDP progressively increased after ligation till LVA formation. Areas in the left ventricle (LV) that underwent fibrosis included the apex, anterior wall and lateral wall but not IVS. Agar intra-chamber cast showed that the bulging of LV wall was prominent in the area of aneurysm. Conclusions Ligation of LAD and Cx at the middle portion could induce develo pment of LVA at a mean area ratio of 33.4%±2.4%which involves the apex, anterior wall and lateral wall of the LV.展开更多
In the present work, the total magnetization in superconducting state is separated into critical state and paramagnetic components in terms of an H(x)-dependent magnetic flux density. Utilizing this model, we reprod...In the present work, the total magnetization in superconducting state is separated into critical state and paramagnetic components in terms of an H(x)-dependent magnetic flux density. Utilizing this model, we reproduce successfully M-H curves measured by Sandu et al. [Phys. Rev. B 74 (2006) 184511] and Sandu et al. [J. Supercond. Incorp. Novel Magn. 17 (2004) 701] for different forms of Jc.展开更多
We investigate in detail the effects of R-parity lepton number violation onthe decay b_1 → bχ_1~0 in the R-parity violating minimal supersymmetric standard model (R_p-MSSM)under the present experimental constraints ...We investigate in detail the effects of R-parity lepton number violation onthe decay b_1 → bχ_1~0 in the R-parity violating minimal supersymmetric standard model (R_p-MSSM)under the present experimental constraints on R_p parameters. In our numerical calculations weconsider two cases of input parameters of the squark and slepton sectors, M_(squark) 【 M_(slepton)and M_(squark) 】 M_(slepton), for comparison. The results show that the relative R-parity violatingcorrection is not very sensitive to the mass of the lightest neutralino bχ_1~0 the degenerateR-parity violating coupling parameter λ′_2 but strongly depends on M_(squark), M_(slepton) tan βand tie degenerate R-parity violating coupling parameter λ′_1. The relative correction is about -4~ 3% and can exceed -6% in some region of parameter space. Therefore, precise experiment analyseson the decay b_1 → bχ_1~0 may provide a probe of the R-parity violation.展开更多
In stratified survey sampling, sometimes we have complete auxiliary information. One of the fundamental questions is how to effectively use the complete auxiliary information at the estimation stage. In this paper, we...In stratified survey sampling, sometimes we have complete auxiliary information. One of the fundamental questions is how to effectively use the complete auxiliary information at the estimation stage. In this paper, we extend the model-calibration method to obtain estimators of the finite population mean by using complete auxiliary information from stratified sampling survey data. We show that the resulting estimators effectively use auxiliary information at the estimation stage and possess a number of attractive features such as asymptotically design-unbiased irrespective of the working model and approximately model-unbiased under the model. When a linear working-model is used, the resulting estimators reduce to the usual calibration estimator(or GREG).展开更多
This paper presents a new transient model ofa standalone (isolated) self excited induction generator (SEIG). This model is based on direct phase quantities and is suitable to study the performance of the generator...This paper presents a new transient model ofa standalone (isolated) self excited induction generator (SEIG). This model is based on direct phase quantities and is suitable to study the performance of the generator under any balanced or unbalanced conditions. It includes a general load as well as general excitation capacitor model. The model has the advantage of connecting or disconnecting the neutral points of the generator electrical system with both excitation capacitors and load. Furthermore, a more accurate magnetization curve is used. Moreover, the simulation results have been verified experimentally.展开更多
The pinning characteristics of a single crystal NdBaaCu3Oy superconductor at low (40 K), intermediate (77.3 K) and high (88 K) temperatures were investigated. The experimental results of the critical current den...The pinning characteristics of a single crystal NdBaaCu3Oy superconductor at low (40 K), intermediate (77.3 K) and high (88 K) temperatures were investigated. The experimental results of the critical current density dc and the apparent pinning potential u o which estimated from magnetic relaxation measurements are compared with the theoretical analysis based on the flux creep-flow model, taking the distribution of the flux pinning strength into account. The number of flux lines in the flux bundle (g2), the most probable value of pinning strength (Am), distribution width of pinning strength (σ-2) and other pinning parameters such as m, γ,δ are determined so that a good fit is obtained between the experimental and theoretical results. The behavior of these parameters is discussed in correspondence to the pinning characteristics of low, intermediate and high temperatures. The observed results are approximately consistent with the theoretical predictions of Brandt et al. model of the order-disorder transition.展开更多
A CAD tool based on a group of efficient algorithms to verify,design,and optimize power/ground networks for standard cell model is presented.Nonlinear programming techniques,branch and bound algorithms and incomplete ...A CAD tool based on a group of efficient algorithms to verify,design,and optimize power/ground networks for standard cell model is presented.Nonlinear programming techniques,branch and bound algorithms and incomplete Cholesky decomposition conjugate gradient method (ICCG) are the three main parts of our work.Users can choose nonlinear programming method or branch and bound algorithm to satisfy their different requirements of precision and speed.The experimental results prove that the algorithms can run very fast with lower wiring resources consumption.As a result,the CAD tool based on these algorithms is able to cope with large-scale circuits.展开更多
基金Standard system on forestry engineering of Ministry ofScience and Technology ( 2004DEA70900-1).
文摘The dimension lumber (45mm×90mm×3700mm) of plantation Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) was graded to four different classes as SS, No. 1, No.2 and No.3, according to national lumber grades authority (NLGA) for structure light framing and structure joists and planks. The properties of apparent density was determined at 15% moisture content, bending strength and stiffness were tested according to American Society for Testing and Materials (ASTM) D198-99, and dynamic modulus of elasticity (Eusw) was measured by ultrasonic technique, for predicting the flexural properties of different grade lumbers. The results showed that Eosw was larger than the static MOE. The relationship between Eusw and static MOE was significant at 0.01 level, and the determination coefficients (R2) of the four grade lumbers followed the sequence as R^2No.2 (0.616)〉 R^2ss (0.567)〉 R^2No1 (0.366)〉 R^2No.3 (0.137). The R^2 of Fusw and MOR were lower than that of the Etru and MOR for each grade. The Eusw of all the grade lumbers, except No.3-grade, had significant correlation with the static MOE and MOR, thus the bending strengthof those grade lumbers can be estimated by the E The Etru valuesof four grade lumbers followed a sequence as No.2-grade (10.701 GPa) 〉 SS-grade (10.359 GPa) 〉 No.l-grade (9.840 GPa) 〉 No.3-grade (9.554 GPa). For the same grade dimension lumber, its Eusw value was larger than static MOE. Mean values of MOR for four grade lumbers follow a sequence as No.2-grade (48.67 MPa) 〉 SS-grade (48.16 MPa) 〉 No.3-grade (46.55 MPa) 〉 No. 1-grade (43.39MPa).
文摘Multivalent polymer chains exhibit excellent prospect in biomedical applications by serving as therapeutic agents. Using three-dimensional (3D) Langevin dynamics simulations, we investigate adsorption behaviors of multivalent polymer chains to a surface with receptors. Multivalent polymer chains display superselective adsorption. Furthermore, the range of density of surface receptors at which a multivalent polymer chain displays a superselective behavior, narrows down for chains with higher density of ligands. Meanwhile, the optimal density of surface receptors where the highest superselectivity is achieved, decreases with increasing the density of ligands. Then, the conformational properties of bound multivalent chains are studied systematically. Interestingly, we find that the equilibrium radius of gyration Rg and its horizontal component have a maximum as a function of the density of surface receptors. The scaling exponents of Rg with the length of chain suggest that with increasing the density of surface receptors., the conformations of a bound multivalent polymer chain first fall in between those of a two-dimensional (2D) and a 3D chain, while it is slightly collapsed subsequently.
基金The project supported by National Natural Science Foundation of China, the Excellent Youth Foundation of Henan Science Committee and the Henan Innovation Project for University Prominent Research Talents
文摘In the minimal supersymmetric standard model with R-parity violation, the lepton number violating top quark interactions can contribute to the top pair production at a linear collider via tree-level u-channel squark exchange diagrams. We calculate such contributions and find that in the allowed range of these R-violating couplings, the top pair production rate as well as the top quark polarization and the forward-backward asymmetry can be significantly altered. By comparing the unpolarized beams with the polarized beams, we find that the polarized beams are more powerful in probing such new physics.
基金the NSFC(10271069)the Foundation of Weinan Teacher's College(08YKZ053)
文摘In this paper, two concepts of relative compactness-the relative strong fuzzy compactness and the relative ultra-fuzzy compactness are defined in L-topological spaces for an arbitrary L-set. Properties of relative strong fuzzy sets and relative ultra-fuzzy compact sets are studied in detail and some characteristic theorems are given. Some examples are illustrated.
文摘We discuss the anomalous magnetic moment of muon in the minimal supersymmetric model with and without right-handed neutrinos. In the same framework, the decay width of is also evaluated. Considering the measured value of muon in the E821 experiment and other experimental constraints on the lepton-flavor-violation processes, we carry out numerical analysis on the concerned observables in the minimal supergravity scenario.
文摘AIM:To investigate the diagnosis of nonalcoholic steatohepatitis(NASH) using contrast ultrasonography in the NASH rat model.METHODS:The liver in methionine choline-deficient diet(MCDD) rats,a NASH model constructed by feeding an MCDD,was examined by contrast ultrasonography at weeks 2,4,8,12 and 16,with late phase images of contrast ultrasonography(Kupffer imaging) in which contrast enhancement was achieved by incorporation of a contrast agent by Kupffer cells(KCs),and images were compared to those in rats taking a regular chow.RESULTS:Decrease in contrast enhancement was observed first in MCDD rats at week 2.KCs were counted based on immunohistochemistry,but their numbers were not reduced and it was assumed that attenuation of contrast enhancement was attributable to reduced phagocytic activity of the KCs.CONCLUSION:It is suggested that clinical application of contrast ultrasonography may be valuable for noninvasive diagnosis of NASH.
基金The project supported by the President Foundation of the Chinese Academy of Sciences and the research fund provided by Graduate School of University of Science and Technology of China
文摘Using the "pseudo-invariant eigen-operator" method we find the energy-gap of the Jaynes-Cummings Hamiltonian model of an atom-cavity system. This model takes the atomic centre-of-mass motion into account. The supersymmetric structure is involved in the Hamiltonian of an atom-cavity system. By selecting suitable supersymmettic generators and using supersymmetrie transformation the Hamiltonian is diagonalized and energy eigenvectors are obtained.
文摘We study the energy level statistics of the SO(5) limit of super-symmetry U(6/4) in odd-A nucleus using the interacting boson-fermion model. The nearest neighbor spacing distribution (NSD) and the spectral rigidity (△3)are investigated, and the factors that affect the properties of level statistics are also discussed. The results show that the boson number N is a dominant factor. If N is small, both the interaction strengths of subgroups SOB(5) and SOBF(5)and the spin play important roles in the energy level statistics, however, along with the increase of N, the statistics distribution would tend to be in Poisson form.
基金The National Natural Science Foundation of China(No.11832013,51878350)the Fundamental Research Funds for the Central Universities(No.B210202023)+3 种基金the Natural Science Foundation of Jiangsu Province(No.BK20180433)the Water Resources Science and Technology Project of Jiangsu Province(No.2020017)the Basic Science Research Project of Nantong(No.JC2020120)the Key Laboratory of Coastal Disaster and Defence of Ministry of Education(Hohai University)(No.202006).
文摘Based on the drying-wetting cycles experiment and the carbonation-drying-wetting cycles experiment for coral aggregate seawater concrete(CASC)with different strength grades,the effects of carbonation-drying-wetting on the durability of CASC are studied with the surface state,mass loss rate,relative dynamic elastic modulus,ultrasonic wave velocity and cube compressive strength as indices.Results show that the mass loss rate of CASC increases gradually with the increase in cycle times in the drying-wetting and carbonation-drying-wetting cycles.The mass loss rate increases relatively slowly at the initial stage but it increases remarkably after 10 cycles.The relative dynamic elastic modulus and ultrasonic wave velocity decrease gradually with the increase in cycle times.After 6 cycles,the decrease rate of the relative dynamic elastic modulus and ultrasonic wave velocity of CASC tends to be flat and the surface is slightly damaged.Compared with the initial 28 d cube compressive strength,the cube compressive strength of CASC decreases by 8.8%to 11.0%.Drying-wetting cycles and carbonation can accelerate seawater erosion on CASC,and drying-wetting cycles result in salting-out and accelerate the destruction of concrete.Therefore,the carbonation-drying-wetting accelerates the destruction of CASC.
基金The project supported in part by National Natural Science Foundation of China under Grant Nos. 90103018 and 90503011
文摘In this paper we introduce bilocal fields in the global color symmetry model and consider color and electrical neutrality conditions simultaneously to study the effect of strange quark mass Ms for the momentum-dependent condensate of color-flavor locked phase. Consequently we find that there will be a quantum phase transition occurring.
基金Supported by the Natural Science Foundation of Liaoning ProvinceChina(2013023010)
文摘Objective To evaluate left atrial function in essential hypertension patients with different patterns of left ventricular geometric models by real-time three-dimensional echocardiography (RT-3DE) and left atrial tracking (EAT).
基金supported by National Natural Science Foundation of China under Grant Nos.10775091 and 10704049
文摘In this paper we theoretically report an unconventional quantum phase transition of a simple Lipkin- Meshkow-Glick model: an interacting collective spin system without external magnetic field. It is shown that this model with integer-spin can exhibit a flrst-order quantum phase transition between different disordered phases, and more intriguingly, possesses a hidden supersymmetry at the critical point. However, for half-integer spin we predict another flrst-order quantum phase transition between two different long-range-ordered phases with a vanishing energy gap, which is induced by the destructive topological quantum interference between the intanton and anti-instanton tunneling paths and accompanies spontaneously breaking of supersymmetry at the same critical point. We also show that, when the total spin-value varies from half-integer to integer this model can exhibit an abrupt variation of Berry phase from π to zero.
文摘Objectives To establish a cost-effective and reproducible procedure for induction of chronic left ventricular aneurysm (LVA) in rabbits. Methods Acute myocardial infarction (AMI) was induced in 35 rabbits via concomitant ligation of the left anterior descending (LAD) coronary artery and the circumflex (Cx) branch at the middle portion. Development of AMI was co n-firmed by ST segment elevation and akinesis of the occluded area. Echocardiography, pathological evaluation, and agar i n-tra-chamber casting were utilized to validate the formation of LVA four weeks after the surgery. Left ventricular end systolic pressure (LVESP) and diastolic pressure (LVEDP) were measured before, immediately after and four weeks after ligation. D i-mensions of the ventricular chamber, thickness of the interventricular septum (IVS) and the left ventricular posterior wall (LVPW) left ventricular end diastolic volume (LVEDV) and systolic volume (LVESV), and ejection fraction (EF) were recorded by echo-cardiography. Results Thirty one (88.6%) rabbits survived myocardial infarction and 26 of them developed aneurysm (83.9%). The mean area of aneurysm was 33.4% ± 2.4% of the left ventricle. LVEF markedly decreased after LVA formation, whereas LVEDV, LVESV and the thickness of IVS as well as the dimension of ventricular chamber from apex to mitral valve annulus significantly increased. LVESP immediately dropped after ligation and recovered to a small extent after LVA formation. LVEDP progressively increased after ligation till LVA formation. Areas in the left ventricle (LV) that underwent fibrosis included the apex, anterior wall and lateral wall but not IVS. Agar intra-chamber cast showed that the bulging of LV wall was prominent in the area of aneurysm. Conclusions Ligation of LAD and Cx at the middle portion could induce develo pment of LVA at a mean area ratio of 33.4%±2.4%which involves the apex, anterior wall and lateral wall of the LV.
文摘In the present work, the total magnetization in superconducting state is separated into critical state and paramagnetic components in terms of an H(x)-dependent magnetic flux density. Utilizing this model, we reproduce successfully M-H curves measured by Sandu et al. [Phys. Rev. B 74 (2006) 184511] and Sandu et al. [J. Supercond. Incorp. Novel Magn. 17 (2004) 701] for different forms of Jc.
文摘We investigate in detail the effects of R-parity lepton number violation onthe decay b_1 → bχ_1~0 in the R-parity violating minimal supersymmetric standard model (R_p-MSSM)under the present experimental constraints on R_p parameters. In our numerical calculations weconsider two cases of input parameters of the squark and slepton sectors, M_(squark) 【 M_(slepton)and M_(squark) 】 M_(slepton), for comparison. The results show that the relative R-parity violatingcorrection is not very sensitive to the mass of the lightest neutralino bχ_1~0 the degenerateR-parity violating coupling parameter λ′_2 but strongly depends on M_(squark), M_(slepton) tan βand tie degenerate R-parity violating coupling parameter λ′_1. The relative correction is about -4~ 3% and can exceed -6% in some region of parameter space. Therefore, precise experiment analyseson the decay b_1 → bχ_1~0 may provide a probe of the R-parity violation.
基金Supported by the National Natural Science Foundation of China(10571093)
文摘In stratified survey sampling, sometimes we have complete auxiliary information. One of the fundamental questions is how to effectively use the complete auxiliary information at the estimation stage. In this paper, we extend the model-calibration method to obtain estimators of the finite population mean by using complete auxiliary information from stratified sampling survey data. We show that the resulting estimators effectively use auxiliary information at the estimation stage and possess a number of attractive features such as asymptotically design-unbiased irrespective of the working model and approximately model-unbiased under the model. When a linear working-model is used, the resulting estimators reduce to the usual calibration estimator(or GREG).
文摘This paper presents a new transient model ofa standalone (isolated) self excited induction generator (SEIG). This model is based on direct phase quantities and is suitable to study the performance of the generator under any balanced or unbalanced conditions. It includes a general load as well as general excitation capacitor model. The model has the advantage of connecting or disconnecting the neutral points of the generator electrical system with both excitation capacitors and load. Furthermore, a more accurate magnetization curve is used. Moreover, the simulation results have been verified experimentally.
文摘The pinning characteristics of a single crystal NdBaaCu3Oy superconductor at low (40 K), intermediate (77.3 K) and high (88 K) temperatures were investigated. The experimental results of the critical current density dc and the apparent pinning potential u o which estimated from magnetic relaxation measurements are compared with the theoretical analysis based on the flux creep-flow model, taking the distribution of the flux pinning strength into account. The number of flux lines in the flux bundle (g2), the most probable value of pinning strength (Am), distribution width of pinning strength (σ-2) and other pinning parameters such as m, γ,δ are determined so that a good fit is obtained between the experimental and theoretical results. The behavior of these parameters is discussed in correspondence to the pinning characteristics of low, intermediate and high temperatures. The observed results are approximately consistent with the theoretical predictions of Brandt et al. model of the order-disorder transition.
文摘A CAD tool based on a group of efficient algorithms to verify,design,and optimize power/ground networks for standard cell model is presented.Nonlinear programming techniques,branch and bound algorithms and incomplete Cholesky decomposition conjugate gradient method (ICCG) are the three main parts of our work.Users can choose nonlinear programming method or branch and bound algorithm to satisfy their different requirements of precision and speed.The experimental results prove that the algorithms can run very fast with lower wiring resources consumption.As a result,the CAD tool based on these algorithms is able to cope with large-scale circuits.