The present study established a mouse model of cerebral infarction by middle cerebral artery occlusion, and monitored the effect of 25 tJg/kg leukemia inhibitory factor and (or) basic fibroblast growth factor admini...The present study established a mouse model of cerebral infarction by middle cerebral artery occlusion, and monitored the effect of 25 tJg/kg leukemia inhibitory factor and (or) basic fibroblast growth factor administration 2 hours after model establishment. Results showed that following administration, the number of endogenous neural stem cells in the infarct area significantly increased, malondialdehyde content in brain tissue homogenates significantly decreased, nitric oxide content, glutathione peroxidase and superoxide dismutase activity significantly elevated, and mouse motor function significantly improved as confirmed by the rotarod and bar grab tests. In particular, the effect of leukemia inhibitory factor in combination with basic fibroblast growth factor was the most significant. Results indicate that leukemia inhibitory factor and basic fibroblast growth factor can improve the microenvironment after cerebral infarction by altering free radical levels, improving the quantity of endogenous neural stem cells, and promoting neurological function of mice with cerebral infarction.展开更多
The metal-free synthesis of graphene on singlecrystal silicon substrates, the most common commercial semiconductor, is of paramount significance for many technological applications. In this work, we report the growth ...The metal-free synthesis of graphene on singlecrystal silicon substrates, the most common commercial semiconductor, is of paramount significance for many technological applications. In this work, we report the growth of graphene directly on an upside-down placed,single-crystal silicon substrate using metal-free, ambientpressure chemical vapor deposition. By controlling the growth temperature, in-plane propagation, edge-propagation, and core-propagation, the process of graphene growth on silicon can be identified. This process produces atomically flat monolayer or bilayer graphene domains, concave bilayer graphene domains, and bulging few-layer graphene domains. This work would be a significant step toward the synthesis of large-area and layer-controlled, high-quality graphene on single-crystal silicon substrates.展开更多
The flux agents in common mould fluxes were fluoride and sodium oxide, which would do great harm to environments. B2O3 was selected as flux. The physical properties of B2O3-containing mould fluxes were studied. The co...The flux agents in common mould fluxes were fluoride and sodium oxide, which would do great harm to environments. B2O3 was selected as flux. The physical properties of B2O3-containing mould fluxes were studied. The corresponding physical properties of 37. 91% CAO-43.09% SiO2-5% Al2O3-5% MgO-2% Li20-7% B2O3 mould fluxes were as follows: the melting point was 909℃, the flowing temperature was 1 160℃, the viscosity and surface tension at 1300 ℃ were 0. 4 Pa · s and 0.32 N/m respectively, which could meet the demands for certain kinds of steels for mould fluxes in continuous casting.展开更多
Similar to free-standing pile groups, piled raft foundations are conventionally designed in which the piles carry the total load of structure and the raft bearing capacity is not taken into account. Numerous studies i...Similar to free-standing pile groups, piled raft foundations are conventionally designed in which the piles carry the total load of structure and the raft bearing capacity is not taken into account. Numerous studies indicated that this method is too conservative. Only when the pile cap is elevated from the ground level,the raft bearing contribution can be neglected. In a piled raft foundation, pileesoileraft interaction is complicated. Although several numerical studies have been carried out to analyze the behaviors of piled raft foundations, very few experimental studies are reported in the literature. The available laboratory studies mainly focused on steel piles. The present study aims to compare the behaviors of piled raft foundations with free-standing pile groups in sand, using laboratory physical models. Cast-in-place concrete piles and concrete raft are used for the tests. The tests are conducted on single pile, single pile in pile group, unpiled raft, free-standing pile group and piled raft foundation. We examine the effects of the number of piles, the pile installation method and the interaction between different components of foundation. The results indicate that the ultimate bearing capacity of the piled raft foundation is considerably higher than that of the free-standing pile group with the same number of piles. With installation of the single pile in the group, the pile bearing capacity and stiffness increase. Installation of the piles beneath the raft decreases the bearing capacity of the raft. When the raft bearing capacity is not included in the design process, the allowable bearing capacity of the piled raft is underestimated by more than 200%. This deviation intensifies with increasing spacing of the piles.展开更多
The nonlinear space charge effect of bunched beam in linac is one of theimportant factors that induces the emittance growth due to the conversion of thefield energy to kinetic energy. Using a cylinder model of space c...The nonlinear space charge effect of bunched beam in linac is one of theimportant factors that induces the emittance growth due to the conversion of thefield energy to kinetic energy. Using a cylinder model of space charge in a linac,we derive the internal energy for a bunched beam with some nonuniform spacecharge distributions, such as Gaussian, waterbag and parabolic distributions inboth the longitudinal and transverse directions. And the emittance growth causedby these nonuniformities is worked out.展开更多
Evidence⁃based practices of public health will benefit from quantification of passive physical activity assessment.This study aims to investigate the reliability of marker⁃free system(MFS)such as Microsoft Kinect in m...Evidence⁃based practices of public health will benefit from quantification of passive physical activity assessment.This study aims to investigate the reliability of marker⁃free system(MFS)such as Microsoft Kinect in measuring upper extremity motion from different angles.Ten healthy participants performed elbow and shoulder extension/flexion along frontal and median anatomical planes for ten pace⁃controlled repetitions,during which the spatiotemporal positions of upper extremity joints were concurrently recorded by two sensors from 0°and 45°viewing angles.Reliability between the two sensors were evaluated using Pearson correlation coefficient,intra⁃class correlation coefficients,and 95%limits of agreement and coefficient of variation.Worse reliability was observed when possibility of occlusion was higher.However,better reliability was found when longer observation interval(10 s)was used as elementary measuring unit than shorter observation interval(2 s).The overall angular reliability of activity as displacement or changes in angle was not satisfactory.The results are expected to inform the industry for the extension of MFS to clinic applications.展开更多
The main goal of the present work is a unitary approach of the physical origin of the corrections to the magnetic moment of free and bound electron. Based on this approach, estimations of lowest order corrections were...The main goal of the present work is a unitary approach of the physical origin of the corrections to the magnetic moment of free and bound electron. Based on this approach, estimations of lowest order corrections were easily obtained. In the non-relativistic limit, the Dirac electron appears as a distribution of charge and current extended over a region of linear dimension of the order of Compton wavelength, which generates its magnetic moment. The e.m. mass (self-energy) of electron outside this region does not participate to this internal dynamics, and consequently does not contribute to the mass term in the formula of the magnetic moment. This is the physical origin of the small increase of the magnetic moment of free electron compared to the value given by Dirac equation. We give arguments that this physical interpretation is self-consistent with the QED approach. The bound electron being localized, it has kinetic energy which means a mass increase from a relativistic point of view, which determines a magnetic moment decrease (relativistic Breit correction). On the other hand, the e.m. mass of electron decreases at the formation of the bound state due to coulomb interaction with the nucleus. We estimated this e.m. mass decrease of bound electron only in its internal dynamics region, and from it the corresponding increase of the magnetic moment (QED correction). The corrections to the mass value are at the origin of the lowest order corrections to the magnetic moment of free and bound electron.展开更多
The effects of corrugated ion channels on electron trajectories and spatial growth rate for a free-electron laser with a one-dimensional helical wiggler have been investigated. Analysis of the steady-state electron tr...The effects of corrugated ion channels on electron trajectories and spatial growth rate for a free-electron laser with a one-dimensional helical wiggler have been investigated. Analysis of the steady-state electron trajectories is performed by solving the equations of motion. Our results show that the presence of a corrugated channel shifts the resonance frequency to smaller values of ion channel frequency. The sixth-order dispersion equation describing the coupling between the electrostatic beam mode and the electromagnetic mode has also been derived. The dispersion relation characteristic is analyzed in detail by numerical solution. Results show that the growth rate of instability in the presence of corrugated ion channels can be greatly enhanced relative to the case of an uniform ion channel.展开更多
Application of virus-free sweetpotato is a breakthrough of sweetpotato production. Several popular varieties were adopted to study their yield increase potential and their use in breeding in this research. The results...Application of virus-free sweetpotato is a breakthrough of sweetpotato production. Several popular varieties were adopted to study their yield increase potential and their use in breeding in this research. The results showed that after virus-elimination, all varieties had a yield increase ranging from 14.95% - 91. 61% and marketable quality improvement, despite the changes in location and season. The changes of dry matter content and disease resistance were not significant. Virus-free sweetpotato performed vigorous vine growth and strong dry matter assimilation ability. Virus-free parents had a slightly high seed setting percentage, but its flowering ability and performance of off-springs were similar to that of its check plants.展开更多
This paper studies and predicts the number growth of China's mobile users by using the power-law regression. We find that the number growth of the mobile users follows a power law. Motivated by the data on the evolut...This paper studies and predicts the number growth of China's mobile users by using the power-law regression. We find that the number growth of the mobile users follows a power law. Motivated by the data on the evolution of the mobile users, we consider scenarios of self-organization of accelerating growth networks into scale-free structures and propose a directed network model, in which the nodes grow following a power-law acceleration. The expressions for the transient and the stationary average degree distributions are obtained by using the Poisson process. This result shows that the model generates appropriate power-law connectivity distributions. Therefore, we find a power-law acceleration invariance of the scale-free networks. The numerical simulations of the models agree with the analytical results well.展开更多
In order to improve the slurry pH control accuracy of the absorption tower in the wet flue gas desulfurization process,a model free adaptive predictive control algorithm for the desulfurization slurry pH which is base...In order to improve the slurry pH control accuracy of the absorption tower in the wet flue gas desulfurization process,a model free adaptive predictive control algorithm for the desulfurization slurry pH which is based on a cyber physical systems framework is proposed.First,aiming to address system characteristics of non-linearity and pure hysteresis in slurry pH change process,a model free adaptive predictive control algorithm based on compact form dynamic linearization is proposed by combining model free adaptive control algorithm with model predictive control algorithm.Then,by integrating information resources with the physical resources in the absorption tower slurry pH control process,an absorption tower slurry pH optimization control system based on cyber physical systems is constructed.It is turned out that the model free adaptive predictive control algorithm under the framework of the cyber physical systems can effectively realize the high-precision tracking control of the slurry pH of the absorption tower,and it has strong robustness.展开更多
Contact angle of ethylene glycol and formamide on (100) faces of NaCl, KCl, and KBr single crystal was measured, and the specific surface free energy (SSFE) was calculated. Dispersion component of the SSFE was 90.57, ...Contact angle of ethylene glycol and formamide on (100) faces of NaCl, KCl, and KBr single crystal was measured, and the specific surface free energy (SSFE) was calculated. Dispersion component of the SSFE was 90.57, 93.78, and 99.52 mN·m-1 for NaCl, KCl, and KBr, respectively. Polar component of the SSFE was 1.05, 0.65, and 0.45 mN·m-1 for NaCl, KCl, and KBr. Such a large ratio of dispersion component of SSFE results from the neutrality of the crystal surface of alkali halide. Lattice component of alkali halide is 780, 717 and 689 kJ·mol-1 for NaCl, KCl, and KBr. The larger lattice enthalpy decreases dispersion component, and increases polar component of the SSFE. The larger lattice enthalpy is considered to enhance the rumpling of the crystal surface more strongly, and such rumpling is considered to decrease the neutrality of the crystal surface.展开更多
One of the most intriguing problems of philosophy and of mankind is the question whether humans have a free will. This question is heavily disputed between natural scientists and especially neuroscientists, who deny f...One of the most intriguing problems of philosophy and of mankind is the question whether humans have a free will. This question is heavily disputed between natural scientists and especially neuroscientists, who deny free will, and philosophers and other groups, who insist on free will. It is perplexing that both sides base their premise on the same precondition, namely naturalism. We will prove that naturalism automatically leads to physicalism, to materialism, and to reductionism. We will also prove here that it is logically not possible to have a free will if naturalism is true. Free will definitely requires an additional substance, a non-material soul, which cannot be part of our universe. This must not be in contradiction to our current knowledge of natural sciences.展开更多
Trading and business in Islam has been identified as the second best profession after agriculture and Prophet Muhammad (PBUH) himself has been engaged in trading. The Islamic theory of market aims to provide optimiz...Trading and business in Islam has been identified as the second best profession after agriculture and Prophet Muhammad (PBUH) himself has been engaged in trading. The Islamic theory of market aims to provide optimization of returns and satisfaction for all stakeholders. It also seeks to make "free market" an instrument of promoting equity and social justice for the welfare of society. It combines tenants from the free market model as well as those in command market economy. Islamic economics identifies certain functional parameters for the efficient functioning of the market to achieve the optimization of returns and social welfare like absence of middle men, prohibition of hoarding, mode of finance free from interest and usury, taxation and other wealth redistribution instruments like Zakat and Khums, asset-based and risk-sharing partnerships and stakes, etc.. It essentially creates conditions for proper functioning of a competitive market as an instrument of economic progress and social equity. In Islamic economics, the role accorded to the state is to ensure that institutions are set up and vigilance officers are appointed which create the specified condition for the proper and fair functioning of the market and hence preventing what is identified as "market failure". The role of the state is to improve the functioning of the market as opposed to that of systematic intervention. This paper tries to examine the Islamic notions of "free market" in the traditional sources like Qur'an, Hadees, the early texts of Islamic Jurisprudence, and contemporary writings on Islamic economic system and to make a comparative analysis with theories of market in capitalist and socialist frameworks. The paper will examine the extent to which Islamic notions of free market offer an alternative model to resolve the problems of growth, inequity, and risk management.展开更多
Objectives of this study were to investigate the effects of milk replacer (MR) acidification for free- access feeding on pre- and post-weaning performance, morbidity and mortality of calves. Calves were randomly assig...Objectives of this study were to investigate the effects of milk replacer (MR) acidification for free- access feeding on pre- and post-weaning performance, morbidity and mortality of calves. Calves were randomly assigned to free-access feeding of acidified (ACID, n = 31) or non-acidified (NON, n = 31) MR, and weaned at 42 days. ACIDMR was prepared to pH 4.0 - 4.5 using formic acid. Intakes were measured daily and weights weekly. Samples of ACID and NON MR were analyzed for coliform and aerobic bacterial growth. After weaning, calves transitioned to a grain-fed veal diet, weighed every 2 weeks. At slaughter (approximately 6 months of age), lungs were evaluated for gross pathological changes and dressed carcass weights were obtained. Generalized linear mixed models were constructed to examine the effects of MR acidification. Differences by treatment group for pre- and post-weaning morbidity and mortality were tested using Pearson’s χ2 and Fisher’s exact tests. ACID calves consumed less MR than NON (10.6 vs. 11.7 L/d, P = 0.02). Acidification tended to promote earlier onset of starter ration consumption (32.0 vs. 39.5 d, hazard ratio = 1.5, P = 0.07), but did not affect average daily starter ration or water intakes across the pre-weaning period. ACID and NON calves did not differ for BW at weaning, pre- or post-weaning ADG or dressed carcass weight. ACID MR had less coliform (P < 0.001) and aerobic bacterial growth (P < 0.001) than NON MR, but odds of disease treatment and mortality did not differ. ACID calves tended to have lower odds of pulmonary lesions during post-mortem inspection than NON calves (OR = 0.3, P = 0.07). These results indicate that under free-access feeding conditions, acidification limited bacterial growth and MR intake, but there were no long-term impacts of acidification on calf performance or health. In conclusion, acidification to pH 4.0 - 4.5 will significantly reduce bacterial growth in milk fed to calves.展开更多
ead-free Sn3.5Ag and Sn3.5Ag0.5Cu solder balls were reflowed by laser to form solder bumps. Shear test was performed on the solder bumps, and SEM/EDX (scanning electron microscopy/energy dispersive X-ray spectrometer...ead-free Sn3.5Ag and Sn3.5Ag0.5Cu solder balls were reflowed by laser to form solder bumps. Shear test was performed on the solder bumps, and SEM/EDX (scanning electron microscopy/energy dispersive X-ray spectrometer) was used to analyze the formation of intermetallic compounds (IMCs) at interface region. A finite element modeling on the temperature gradient and distribution at the interface of solder bump during laser reflow process was conducted to elucidate the mechanism of the IMCs growth direction. The results show that the parameters window for laser reflow bumping of Sn3.5Ag0.5Cu was wider than that of Sn3.5Ag. The shear strength of Sn3.5Ag0.5Cu solder bump was comparable to that of Sn3.5Ag solder bump, and was not affected obviously by laser power and irradiation time when appropriate parameters were used. Both laser power and heating time had a significant effect on the formation of IMCs. A continuous AuSn4 intermetallic compound layer and some needle-like AuSn4 were observed at the interface of solder and Au/Ni/Cu metallization layer when the laser power is small. The formation of needle-like AuSn4 was due to temperature gradient at the interface, and the direction of temperature gradient was the preferred growth direction of AuSn4. With increasing the laser power and heating time, the needle-like AuSn4 IMCs dissolved into the bulk solder, and precipitated out once again during solidification along the grain boundary of the solder bump.展开更多
Through theoretical analysis,we show how aligning pulse durations affect the degree and the time-rate slope of nitrogen field-free alignment at a fixed pulse intensity.It is found that both the degree and the slope fi...Through theoretical analysis,we show how aligning pulse durations affect the degree and the time-rate slope of nitrogen field-free alignment at a fixed pulse intensity.It is found that both the degree and the slope first increase,then saturate,and finally decrease with the increasing pump duration.The optimal durations for the maximum degree and the maximum slope of the alignment are found to be different.Additionally,they are found to mainly depend on the molecular rotational period,and are affected by the temperature and the aligning pump intensities.The mechanism of molecular alignment is also discussed.展开更多
The structural changes that took place in the Turkish Economy following the January 24,1980 decisions and their aftermath.With the policies of opening up to the outside world and transition to a free market economy in...The structural changes that took place in the Turkish Economy following the January 24,1980 decisions and their aftermath.With the policies of opening up to the outside world and transition to a free market economy in the 1980s in the Turkish Economy,there were radical changes in the structure of the economy and the prices of all goods and services began to be determined by the market under market conditions.In the 1980s,which can be called the transition period to the Free Market Economy and open economy,efforts were made to privatize state institutions and determine the prices of goods and services under free market conditions in order to withdraw the state from economic life,while on the other hand,efforts were made to grant freedom to foreign trade.While these two main issues were being realized,the import substitution industrialization strategy was abandoned and the export-oriented growth model was started to be implemented.The last step of this opening up and liberalization process was realized with the decision number 32 in 1989.We can say that with the liberalization of capital movements in the 1990s,economic growth and development were tried to be achieved through hot money inflows rather than direct foreign investments.This trend made the economy more open to crises,and for the first time,a crisis occurred in the form of the 1994 economic crisis,which was understood to be caused by hot money.The 1994 economic crisis was tried to be overcome by providing state guarantees to bank deposits and applying high interest rates.Thus,it is noteworthy that high inflation was experienced in the period until the 2001 economic crisis.We can say that the financial crisis that occurred in 2001 as a result of the environment that occurred in the 1990s deepened and turned into an economic crisis,and the economic and political effects of this crisis were experienced.Although there have been many economic crises in the history of the Republic,this crisis is considered to be the most deeply effective.While the crisis was overcome with the stand by agreement made with the IMF and the announced Transition to a Strong Economy program,the economy started to grow rapidly with the ease of using foreign resources,and political stability seems to have enabled this economic growth process to continue uninterruptedly except 2009.There was also a decrease in inflation rates.展开更多
基金supported by grants from the Ministry of Education of China,No.[2007]1108Tianjin Health Bureau,No.06KG05
文摘The present study established a mouse model of cerebral infarction by middle cerebral artery occlusion, and monitored the effect of 25 tJg/kg leukemia inhibitory factor and (or) basic fibroblast growth factor administration 2 hours after model establishment. Results showed that following administration, the number of endogenous neural stem cells in the infarct area significantly increased, malondialdehyde content in brain tissue homogenates significantly decreased, nitric oxide content, glutathione peroxidase and superoxide dismutase activity significantly elevated, and mouse motor function significantly improved as confirmed by the rotarod and bar grab tests. In particular, the effect of leukemia inhibitory factor in combination with basic fibroblast growth factor was the most significant. Results indicate that leukemia inhibitory factor and basic fibroblast growth factor can improve the microenvironment after cerebral infarction by altering free radical levels, improving the quantity of endogenous neural stem cells, and promoting neurological function of mice with cerebral infarction.
基金financially supported by the National Natural Science Foundation of China (NSFC) (Grant Nos. 11405253, 11225527, 11575283, 11205235, U1632129, U1332205)Shanghai Science Foundation (14YF1407500)the Youth Innovation Promotion Association CAS (2016237)
文摘The metal-free synthesis of graphene on singlecrystal silicon substrates, the most common commercial semiconductor, is of paramount significance for many technological applications. In this work, we report the growth of graphene directly on an upside-down placed,single-crystal silicon substrate using metal-free, ambientpressure chemical vapor deposition. By controlling the growth temperature, in-plane propagation, edge-propagation, and core-propagation, the process of graphene growth on silicon can be identified. This process produces atomically flat monolayer or bilayer graphene domains, concave bilayer graphene domains, and bulging few-layer graphene domains. This work would be a significant step toward the synthesis of large-area and layer-controlled, high-quality graphene on single-crystal silicon substrates.
基金Item Sponsored by National Natural Science Foundation of China (50474037) Jiangsu Province Natural Science Foundation forUniversity of China (04BJK430022)
文摘The flux agents in common mould fluxes were fluoride and sodium oxide, which would do great harm to environments. B2O3 was selected as flux. The physical properties of B2O3-containing mould fluxes were studied. The corresponding physical properties of 37. 91% CAO-43.09% SiO2-5% Al2O3-5% MgO-2% Li20-7% B2O3 mould fluxes were as follows: the melting point was 909℃, the flowing temperature was 1 160℃, the viscosity and surface tension at 1300 ℃ were 0. 4 Pa · s and 0.32 N/m respectively, which could meet the demands for certain kinds of steels for mould fluxes in continuous casting.
文摘Similar to free-standing pile groups, piled raft foundations are conventionally designed in which the piles carry the total load of structure and the raft bearing capacity is not taken into account. Numerous studies indicated that this method is too conservative. Only when the pile cap is elevated from the ground level,the raft bearing contribution can be neglected. In a piled raft foundation, pileesoileraft interaction is complicated. Although several numerical studies have been carried out to analyze the behaviors of piled raft foundations, very few experimental studies are reported in the literature. The available laboratory studies mainly focused on steel piles. The present study aims to compare the behaviors of piled raft foundations with free-standing pile groups in sand, using laboratory physical models. Cast-in-place concrete piles and concrete raft are used for the tests. The tests are conducted on single pile, single pile in pile group, unpiled raft, free-standing pile group and piled raft foundation. We examine the effects of the number of piles, the pile installation method and the interaction between different components of foundation. The results indicate that the ultimate bearing capacity of the piled raft foundation is considerably higher than that of the free-standing pile group with the same number of piles. With installation of the single pile in the group, the pile bearing capacity and stiffness increase. Installation of the piles beneath the raft decreases the bearing capacity of the raft. When the raft bearing capacity is not included in the design process, the allowable bearing capacity of the piled raft is underestimated by more than 200%. This deviation intensifies with increasing spacing of the piles.
基金The project supported by the National Natural Science Foundation of China(NSFC) the Science Foundation of Chinese Nuclear Industry
文摘The nonlinear space charge effect of bunched beam in linac is one of theimportant factors that induces the emittance growth due to the conversion of thefield energy to kinetic energy. Using a cylinder model of space charge in a linac,we derive the internal energy for a bunched beam with some nonuniform spacecharge distributions, such as Gaussian, waterbag and parabolic distributions inboth the longitudinal and transverse directions. And the emittance growth causedby these nonuniformities is worked out.
基金Sponsored by the National Natural Science Foundation of China(Grant No.51708152)the Science and Technology Innovation Committee of Shenzhen Municipality(Grant No.JCYJ20170811155435737).
文摘Evidence⁃based practices of public health will benefit from quantification of passive physical activity assessment.This study aims to investigate the reliability of marker⁃free system(MFS)such as Microsoft Kinect in measuring upper extremity motion from different angles.Ten healthy participants performed elbow and shoulder extension/flexion along frontal and median anatomical planes for ten pace⁃controlled repetitions,during which the spatiotemporal positions of upper extremity joints were concurrently recorded by two sensors from 0°and 45°viewing angles.Reliability between the two sensors were evaluated using Pearson correlation coefficient,intra⁃class correlation coefficients,and 95%limits of agreement and coefficient of variation.Worse reliability was observed when possibility of occlusion was higher.However,better reliability was found when longer observation interval(10 s)was used as elementary measuring unit than shorter observation interval(2 s).The overall angular reliability of activity as displacement or changes in angle was not satisfactory.The results are expected to inform the industry for the extension of MFS to clinic applications.
文摘The main goal of the present work is a unitary approach of the physical origin of the corrections to the magnetic moment of free and bound electron. Based on this approach, estimations of lowest order corrections were easily obtained. In the non-relativistic limit, the Dirac electron appears as a distribution of charge and current extended over a region of linear dimension of the order of Compton wavelength, which generates its magnetic moment. The e.m. mass (self-energy) of electron outside this region does not participate to this internal dynamics, and consequently does not contribute to the mass term in the formula of the magnetic moment. This is the physical origin of the small increase of the magnetic moment of free electron compared to the value given by Dirac equation. We give arguments that this physical interpretation is self-consistent with the QED approach. The bound electron being localized, it has kinetic energy which means a mass increase from a relativistic point of view, which determines a magnetic moment decrease (relativistic Breit correction). On the other hand, the e.m. mass of electron decreases at the formation of the bound state due to coulomb interaction with the nucleus. We estimated this e.m. mass decrease of bound electron only in its internal dynamics region, and from it the corresponding increase of the magnetic moment (QED correction). The corrections to the mass value are at the origin of the lowest order corrections to the magnetic moment of free and bound electron.
文摘The effects of corrugated ion channels on electron trajectories and spatial growth rate for a free-electron laser with a one-dimensional helical wiggler have been investigated. Analysis of the steady-state electron trajectories is performed by solving the equations of motion. Our results show that the presence of a corrugated channel shifts the resonance frequency to smaller values of ion channel frequency. The sixth-order dispersion equation describing the coupling between the electrostatic beam mode and the electromagnetic mode has also been derived. The dispersion relation characteristic is analyzed in detail by numerical solution. Results show that the growth rate of instability in the presence of corrugated ion channels can be greatly enhanced relative to the case of an uniform ion channel.
文摘Application of virus-free sweetpotato is a breakthrough of sweetpotato production. Several popular varieties were adopted to study their yield increase potential and their use in breeding in this research. The results showed that after virus-elimination, all varieties had a yield increase ranging from 14.95% - 91. 61% and marketable quality improvement, despite the changes in location and season. The changes of dry matter content and disease resistance were not significant. Virus-free sweetpotato performed vigorous vine growth and strong dry matter assimilation ability. Virus-free parents had a slightly high seed setting percentage, but its flowering ability and performance of off-springs were similar to that of its check plants.
基金supported by the National Natural Science Foundation of China(Grant No.70871082)the Shanghai Leading Academic Discipline Project,China(Grant No.S30504)
文摘This paper studies and predicts the number growth of China's mobile users by using the power-law regression. We find that the number growth of the mobile users follows a power law. Motivated by the data on the evolution of the mobile users, we consider scenarios of self-organization of accelerating growth networks into scale-free structures and propose a directed network model, in which the nodes grow following a power-law acceleration. The expressions for the transient and the stationary average degree distributions are obtained by using the Poisson process. This result shows that the model generates appropriate power-law connectivity distributions. Therefore, we find a power-law acceleration invariance of the scale-free networks. The numerical simulations of the models agree with the analytical results well.
基金Supported by National Natural Science Foundation of China(61873006,61673053)National Key Research and Development Project(2018YFC1602704,2018YFB1702704)。
文摘In order to improve the slurry pH control accuracy of the absorption tower in the wet flue gas desulfurization process,a model free adaptive predictive control algorithm for the desulfurization slurry pH which is based on a cyber physical systems framework is proposed.First,aiming to address system characteristics of non-linearity and pure hysteresis in slurry pH change process,a model free adaptive predictive control algorithm based on compact form dynamic linearization is proposed by combining model free adaptive control algorithm with model predictive control algorithm.Then,by integrating information resources with the physical resources in the absorption tower slurry pH control process,an absorption tower slurry pH optimization control system based on cyber physical systems is constructed.It is turned out that the model free adaptive predictive control algorithm under the framework of the cyber physical systems can effectively realize the high-precision tracking control of the slurry pH of the absorption tower,and it has strong robustness.
文摘Contact angle of ethylene glycol and formamide on (100) faces of NaCl, KCl, and KBr single crystal was measured, and the specific surface free energy (SSFE) was calculated. Dispersion component of the SSFE was 90.57, 93.78, and 99.52 mN·m-1 for NaCl, KCl, and KBr, respectively. Polar component of the SSFE was 1.05, 0.65, and 0.45 mN·m-1 for NaCl, KCl, and KBr. Such a large ratio of dispersion component of SSFE results from the neutrality of the crystal surface of alkali halide. Lattice component of alkali halide is 780, 717 and 689 kJ·mol-1 for NaCl, KCl, and KBr. The larger lattice enthalpy decreases dispersion component, and increases polar component of the SSFE. The larger lattice enthalpy is considered to enhance the rumpling of the crystal surface more strongly, and such rumpling is considered to decrease the neutrality of the crystal surface.
文摘One of the most intriguing problems of philosophy and of mankind is the question whether humans have a free will. This question is heavily disputed between natural scientists and especially neuroscientists, who deny free will, and philosophers and other groups, who insist on free will. It is perplexing that both sides base their premise on the same precondition, namely naturalism. We will prove that naturalism automatically leads to physicalism, to materialism, and to reductionism. We will also prove here that it is logically not possible to have a free will if naturalism is true. Free will definitely requires an additional substance, a non-material soul, which cannot be part of our universe. This must not be in contradiction to our current knowledge of natural sciences.
文摘Trading and business in Islam has been identified as the second best profession after agriculture and Prophet Muhammad (PBUH) himself has been engaged in trading. The Islamic theory of market aims to provide optimization of returns and satisfaction for all stakeholders. It also seeks to make "free market" an instrument of promoting equity and social justice for the welfare of society. It combines tenants from the free market model as well as those in command market economy. Islamic economics identifies certain functional parameters for the efficient functioning of the market to achieve the optimization of returns and social welfare like absence of middle men, prohibition of hoarding, mode of finance free from interest and usury, taxation and other wealth redistribution instruments like Zakat and Khums, asset-based and risk-sharing partnerships and stakes, etc.. It essentially creates conditions for proper functioning of a competitive market as an instrument of economic progress and social equity. In Islamic economics, the role accorded to the state is to ensure that institutions are set up and vigilance officers are appointed which create the specified condition for the proper and fair functioning of the market and hence preventing what is identified as "market failure". The role of the state is to improve the functioning of the market as opposed to that of systematic intervention. This paper tries to examine the Islamic notions of "free market" in the traditional sources like Qur'an, Hadees, the early texts of Islamic Jurisprudence, and contemporary writings on Islamic economic system and to make a comparative analysis with theories of market in capitalist and socialist frameworks. The paper will examine the extent to which Islamic notions of free market offer an alternative model to resolve the problems of growth, inequity, and risk management.
文摘Objectives of this study were to investigate the effects of milk replacer (MR) acidification for free- access feeding on pre- and post-weaning performance, morbidity and mortality of calves. Calves were randomly assigned to free-access feeding of acidified (ACID, n = 31) or non-acidified (NON, n = 31) MR, and weaned at 42 days. ACIDMR was prepared to pH 4.0 - 4.5 using formic acid. Intakes were measured daily and weights weekly. Samples of ACID and NON MR were analyzed for coliform and aerobic bacterial growth. After weaning, calves transitioned to a grain-fed veal diet, weighed every 2 weeks. At slaughter (approximately 6 months of age), lungs were evaluated for gross pathological changes and dressed carcass weights were obtained. Generalized linear mixed models were constructed to examine the effects of MR acidification. Differences by treatment group for pre- and post-weaning morbidity and mortality were tested using Pearson’s χ2 and Fisher’s exact tests. ACID calves consumed less MR than NON (10.6 vs. 11.7 L/d, P = 0.02). Acidification tended to promote earlier onset of starter ration consumption (32.0 vs. 39.5 d, hazard ratio = 1.5, P = 0.07), but did not affect average daily starter ration or water intakes across the pre-weaning period. ACID and NON calves did not differ for BW at weaning, pre- or post-weaning ADG or dressed carcass weight. ACID MR had less coliform (P < 0.001) and aerobic bacterial growth (P < 0.001) than NON MR, but odds of disease treatment and mortality did not differ. ACID calves tended to have lower odds of pulmonary lesions during post-mortem inspection than NON calves (OR = 0.3, P = 0.07). These results indicate that under free-access feeding conditions, acidification limited bacterial growth and MR intake, but there were no long-term impacts of acidification on calf performance or health. In conclusion, acidification to pH 4.0 - 4.5 will significantly reduce bacterial growth in milk fed to calves.
基金supported by the National Natural Science Foundation of China under grant No.50475031/E052104.
文摘ead-free Sn3.5Ag and Sn3.5Ag0.5Cu solder balls were reflowed by laser to form solder bumps. Shear test was performed on the solder bumps, and SEM/EDX (scanning electron microscopy/energy dispersive X-ray spectrometer) was used to analyze the formation of intermetallic compounds (IMCs) at interface region. A finite element modeling on the temperature gradient and distribution at the interface of solder bump during laser reflow process was conducted to elucidate the mechanism of the IMCs growth direction. The results show that the parameters window for laser reflow bumping of Sn3.5Ag0.5Cu was wider than that of Sn3.5Ag. The shear strength of Sn3.5Ag0.5Cu solder bump was comparable to that of Sn3.5Ag solder bump, and was not affected obviously by laser power and irradiation time when appropriate parameters were used. Both laser power and heating time had a significant effect on the formation of IMCs. A continuous AuSn4 intermetallic compound layer and some needle-like AuSn4 were observed at the interface of solder and Au/Ni/Cu metallization layer when the laser power is small. The formation of needle-like AuSn4 was due to temperature gradient at the interface, and the direction of temperature gradient was the preferred growth direction of AuSn4. With increasing the laser power and heating time, the needle-like AuSn4 IMCs dissolved into the bulk solder, and precipitated out once again during solidification along the grain boundary of the solder bump.
基金Project supported by the National Natural Science Foundation of China (Grants Nos. 10634020,11074014 and 10821062)
文摘Through theoretical analysis,we show how aligning pulse durations affect the degree and the time-rate slope of nitrogen field-free alignment at a fixed pulse intensity.It is found that both the degree and the slope first increase,then saturate,and finally decrease with the increasing pump duration.The optimal durations for the maximum degree and the maximum slope of the alignment are found to be different.Additionally,they are found to mainly depend on the molecular rotational period,and are affected by the temperature and the aligning pump intensities.The mechanism of molecular alignment is also discussed.
文摘The structural changes that took place in the Turkish Economy following the January 24,1980 decisions and their aftermath.With the policies of opening up to the outside world and transition to a free market economy in the 1980s in the Turkish Economy,there were radical changes in the structure of the economy and the prices of all goods and services began to be determined by the market under market conditions.In the 1980s,which can be called the transition period to the Free Market Economy and open economy,efforts were made to privatize state institutions and determine the prices of goods and services under free market conditions in order to withdraw the state from economic life,while on the other hand,efforts were made to grant freedom to foreign trade.While these two main issues were being realized,the import substitution industrialization strategy was abandoned and the export-oriented growth model was started to be implemented.The last step of this opening up and liberalization process was realized with the decision number 32 in 1989.We can say that with the liberalization of capital movements in the 1990s,economic growth and development were tried to be achieved through hot money inflows rather than direct foreign investments.This trend made the economy more open to crises,and for the first time,a crisis occurred in the form of the 1994 economic crisis,which was understood to be caused by hot money.The 1994 economic crisis was tried to be overcome by providing state guarantees to bank deposits and applying high interest rates.Thus,it is noteworthy that high inflation was experienced in the period until the 2001 economic crisis.We can say that the financial crisis that occurred in 2001 as a result of the environment that occurred in the 1990s deepened and turned into an economic crisis,and the economic and political effects of this crisis were experienced.Although there have been many economic crises in the history of the Republic,this crisis is considered to be the most deeply effective.While the crisis was overcome with the stand by agreement made with the IMF and the announced Transition to a Strong Economy program,the economy started to grow rapidly with the ease of using foreign resources,and political stability seems to have enabled this economic growth process to continue uninterruptedly except 2009.There was also a decrease in inflation rates.