SCIENCE CHINA Information Sciences(Monthly)

正SCIENCE CHINA Information Sciences is a peer-reviewed monthly academic journal supervised by the Chinese Academy of Sciences, and co-sponsored by the Chinese Academy of Sciences and the National Natural Science Foundation of China.Its primary     

SCIENCE CHINA Information Sciences(Monthly)

正SCIENCE CHINA Information Sciences is a peer-reviewed monthly academic journal supervised by the Chinese Academy of Sciences, and co-sponsored by the Chinese Academy of Sciences and the National Natural Science Foundation of China.Its primary     

A novel order reduction method for nonlinear dynamical system under external periodic excitations

The concept of approximate inertial manifold (AIM) is extended to develop a kind of nonlinear order reduction technique for non-autonomous nonlinear systems in second-order form in this paper. Using the modal transformation, a large nonlinear dynamical system is split into a ‘master’ subsystem, a ‘slave’ subsystem, and a ‘negligible’ subsystem. Accordingly, a novel order reduction method (Method I) is developed to construct a low order subsystem by neglecting the ‘negligible’ subsystem and slaving the ‘slav...     

Microstructure and texture evolution during warm compression of the magnesium alloy AZ31

The evolution of the microstructure and texture with strain during compression at 150℃of the magnesium alloy AZ31 has been investigated using the electron backscattered diffraction(EBSD)technique.The initial samples were chosen to have a strong basal plane texture with the crystal c-axes perpendicular to the compression direction.The EBSD data provide evidence concerning the relative activity of both{10-12}extension twinning and slip,and suggest that non-basalc+a slip is important in samples deformed to a strain of more than 0.2.The relative contributions of the twinning and the slip during deformation have been discussed based on the results above.     

Understanding of the influence of process parameters on the heat transfer behavior at the metal/die interface in high pressure die casting process

The current paper focuses on the influence of the process parameters on the peak values of the interfacial heat transfer coefficient(IHTC)at metal/die interface during high pressure die casting(HPDC)process.A"step shape"casting and AM50 alloy were used during the experiment.The IHTC was determined by solving the inverse thermal problem based on the measured temperature inside the die.Results show that the initial die surface temperature(IDST,TDI)has a dominant influence while the casting pressure and fast shot velocity have a secondary influence on the IHTC peak values.By curve fitting,it was found that the IHTC peak value(hmax)changes as a function of the IDST in a manner of hmax=e αTγ DI .Such relationship between the IHTC peak value and the IDST can also be found when the casting alloy is ADC12,indicating that this phenomenon is a common characteristic in the HPDC process.     

Nonlinear dynamics of angle-ply composite laminated thin plate with third-order shear deformation

An asymptotic perturbation method is presented based on the Fourier expansion and temporal rescaling to investigate the nonlinear oscillations and chaotic dynamics of a simply supported angle-ply composite laminated rectangular thin plate with parametric and external excitations. According to the Reddy’s third-order plate theory, the governing equations of motion for the angle-ply composite laminated rectangular thin plate are derived by using the Hamilton’s principle. Then, the Galerkin procedure is applie...     

Dielectric tunable properties of BaTi_4O_9-doped Ba_(0.6)Sr_(0.4)TiO_3 microwave composite ceramics

BaTi4O9-doped Ba0.6Sr0.4TiO3(BST) composite ceramics were prepared by the conventional solid-state reaction and their structure,dielectric nonlinear characteristics and microwave dielectric properties were investigated.The secondary phase of the orthorhombic structure Ba4Ti13O30 is formed among BST composite ceramics with the increase of BaTi4O9.At the same time,a duplex or bimodal grains size distribution shows fine grains in a coarse grain matrix.The degree of frequency dispersion of dielectric permittivity below Tm is increased initially and then decreased with respect to BaTi4O9.As the BaTi4O9 content increases,the tunability of composite ceramics decreases,while the Q value increases.Interestingly,70 wt%BaTi4O9-doped BST has a tunability～4.0%(under 30 kV/cm biasing) versus a permittivity～68 and quality factor ～134.1(at～3.2 GHz) .     

Complex dynamics of functionally graded plates with thermal load in 1:2 internal resonance

Complex dynamics of the simply-supported functionally graded (FG) rectangular plates with thermal load is investigated. Based on Reddy’s third-order shear deformation theory and the von Karman nonlinear strain-displacement relations, ordinary differential equations (ODEs) of the plate’s transversal oscillation are derived by using Hamilton’s principle and Galerkin’s approach. Solutions’ classification of the equations in 1:2 internal resonance is analyzed. Particular results of a simply- supported aluminum-...     

Process optimization of reaction of acid leaching residue of asbestos tailing and sodium hydroxide aqueous solution

Silica is the major component of the acid leaching residue of asbestos tailing.The waterglass solution can be prepared by the reaction of the residue with sodium hydroxide aqueous solution.Compared to the high temperature reaction method,this process is environmental friendly and low cost.In this paper,the reaction process of the residue and the sodium hydroxide aqueous solution is optimized.The optimum reaction process parameters are as follows:the usage of sodium hydroxide is 26.4 g/100 g acid leaching residue,the reaction temperature is 90℃,the reaction time is 1 h,and the ratio of the liquid/solid is 2.0.The significance sequence of the process parameters to the alkali leaching reaction effect is the usage of sodium hydroxidethe ratio of the liquid/solidthe reaction timethe reaction temperature.The significance sequence to the leaching ratio of SiO2 is the ratio of the liquid/solidthe usage of sodium hydroxidethe reaction timethe reaction temperature.The significance sequence to the modulus of the sodium silicate is the ratio of the liquid/solidthe usage of sodium hydroxidethe reaction timethe reaction temperature.Under the optimum conditions,the leaching ratio of the SiO2 is 77.5%,and the modulus of the sodium silicate is 3.15.The XRD analysis result indicates that the major components of the alkali leaching residue are serpentine,talc,quartz and some albite.     

One-step synthesis route of the aligned and non-aligned single crystalline α-Si_3N_4 nanowires

This paper reports the bulk synthesis route of the aligned and non-aligned high-qualityα-Si 3 N4 nanowires(NWs) which were grown directly from the Si substrate by vapor phase deposition at 1050℃.The as-grown products were characterized by employing XRD,SEM,HRTEM and photoluminescence.The microscopic results revealed that the products consist of single crystalline aligned and non-alignedα-Si 3 N4 NWs having a same diameter range of 30-100 nm and different lengths of about hundreds of microns.The XRD observation revealed that the products consist ofα-phase Si 3 N4 NWs.The room temperature PL spectra indicated that the NWs have good emission property.The non-aligned NWs were formed at lower temperature as compared with aligned NWs.Our method is a simple and one-step procedure to synthesize the bulk-quantity and high-purity aligned and non-alignedα-Si 3 N4 NWs at a relatively low temperature.The possible growth mechanism was also briefly discussed.     

我国教育质量奖模型实证研究

高等教育的快速发展要求必须解决教育质量的评价标准和实行教育质量评价的方法途径，以确保高教事业发展的质、量统一。目前，美国和欧洲都建立了自己的教育质量奖评价准则。为了提高我国的教育质量，加快我国教育国际化的进程，本文提出了我国的教育质量奖评价标准的构建模型，并通过实证分析确定了模型中各参数的权重结构，为我国的教育评估机制的完善提供了必要的参考。     

Scientific Instruments for Education in Early Twentieth-Century Spain

1898 marked a crucial point in the end of the nineteenth-century Spanish crisis. The military defeat ending the Spanish-American War was seen as proof that the country was in terminal decline. With the ideals of regeneration spreading throughout Spanish society, the State became more interested in supporting and sponsoring science and technology, as well as in creating a modern educational system. The resulting reforms reflected this strong interest in scientific education, and consequently, the first decades of the twentieth century saw a turning point in the development of science and technology in Spain. Some recent papers have discussed various initiatives taken by Spanish governments, particularly in the creation of new official institutions. Such institutions played an important role in the development of science and technology, but their activity in the promotion of scientific education was very limited. However, other governmental initiatives were taken in order to develop this area, particularly focusing on the acquisition of scientific instruments. Scientific instruments were needed not only to improve Spanish scientific research but also to improve the teaching of experimental sciences. These instruments were specifically adapted for use by students. This paper aims to present some of the lesser-known individuals and firms who, in the new social and cultural context, provided scientific instruments for educational centres in order to meet the increasing demand for this material in Spanish educational institutions during these years.     

Astronomical and chronological calculations at Newminster in 1428

Oliver Heaviside and Sir William Thomson (later Lord Kelvin) stand in such contrast that the life of each serves to illuminate the life of the other. Thomson's talents, which were recognized at an early age, were cultivated with possibly unsurpassed educational opportunities, whereas Heaviside had scarcely any educational opportunities and was essentially self-taught. Nevertheless, Heaviside's published and unpublished works suggest that the breadth and depth of his learning were more or less comparable to Thomson's. Being an outstanding student at Cambridge brought Thomson in contact with scientists of the first rank, and he learned without effort how to get along with his peers. That pleasing quality was essentially absent in Heaviside, whose personality was as prickly as a porcupine, almost without grace. But underneath this rough exterior was a noble genius who never exploited his rare talents to his own advantage, but instead dedicated them to learning the Truth for its own sake. As to personal temperament, educational opportunities, professional and social activities, Heaviside and Thomson were poles apart. But they maintained a correspondence which is significant, and Thomson's assistance to Heaviside is noteworthy.     

高水效农业是我国农业发展的必由之路

本文提出了高水效农业是指同时追求和实现单位耗水的高水分利用效率、高经济效益、高生态效益及社会效益的一种具有高新科学技术体系和经济市场紧密结合的新型农业体系。是我国农业发展的必由之路。结合我国目前粮食生产下降的问题和节水农业发展，分析了我国粮食减产的原因主要是南方经济发达地区重工商业轻农业，因此粮食生产不足。因此，提出了我们不但要重视北方节水农业的发展，更要重视南方高水效农业的发展，以解决北粮南运的状况。从粮食安全和经济安全及水安全，南北方农业资源，农业结构调整，农艺抗旱节水措施，作物高产育种，高效的水管理体系等方面，论述了发展高水效农业发展的迫切性、可行性和必然性。     

Why does the Chinese public accept evolution?

A substantial proportion of Chinese nationals seem to accept evolution, and the country is sometimes held up to show that the sorry state of evolution acceptance in the United States is not inevitable. Attempts to improve evolution acceptance generally focus on improving communication, curricular reform, and even identifying cognitive mechanisms that bias people against evolution. What is it that the Chinese scientific community did so well, and can it be generalized? This paper argues that evolution acceptance in China has a very specific history, one that other countries are very unlikely to emulate. We show that the interactions among science, education, mass media, social and political movements, and ideological arguments about evolution greatly influenced the Chinese public's understanding and acceptance of evolution. We find that it was not just formal education, but many more ideologically motivated methods of evolution exposure that contributed to the high rate of acceptance. But since the purpose of evolution dissemination has moved beyond merely teaching biology, the Chinese public persists with substantial misunderstandings of the theory. Thus, bottom line percentage of acceptance figures can be misleading; the details and the history really matter.     

Augustus De Morgan and the propagation of moral mathematics

In the early nineteenth century, Henry Brougham endeavored to improve the moral character of England through the publication of educational texts. Soon after, Brougham helped form the Society for the Diffusion of Useful Knowledge to carry his plan of moral improvement to the people. Despite its goal of improving the nation’s moral character, the Society refused to publish any treatises on explicitly moral or religious topics. Brougham instead turned to a mathematician, Augustus De Morgan, to promote mathematics as a rational subject that could provide the link between the secular and religious worlds. Using specific examples gleaned from the treatises of the Society, this article explores both how mathematics was intended to promote the development of reason and morality and how mathematical content was shaped to fit this particular view of the usefulness of mathematics. In the course of these treatises De Morgan proposed a fundamentally new pedagogical approach, one which focused on the student and the role mathematics could play in moral education.     

The impact of W. K. Röntgen's discovery on the use of internalizable sources of ionizing energy in diagnostic and therapeutic nuclear medicine

The early history of cathode rays, X-rays and a third kind of natural radiation from several minerals and atomic fission is described. In this way the fundamental concept of radioactivity, laws of decay and atomic models were developed. With artificial radioactive isotopes, new tailored radiopharmaceuticals could be introduced into metabolic research, medical diagnostics and therapy. Von Hevesy's concept of the dynamic state of body constituents led to examination of the locations and movements of labelled atoms and molecules as a function of time. That was the birth of nucler medicine. The principles and value at the molecular level of several specific tracer studies in research and diagnostic or therapeutic use are explained. Typically, diagnostic tests with tracer agents are non-invasive and have low radiation exposure. Competing with other diagnostic and therapeutic modalities, nuclear medicine is a speciality in its own right. But there are moves to classify it as a subspecialization of other organ-oriented clinical disciplines. That is a misunderstanding of the radiologist's role and does not answer the question: What is the best way of woking for the patient? New horizons in diagnostic modalities, biochemistry, immunology, imaging and the use of immunogenic therapeutic agents demand a continuous cooperation within interdisciplinary teams. That is as necessary with radiologic departments, participating in changed organizational structures, as with other clinical departments.     

The Young J. H. van 't Hoff: The Background to the Publication of his 1874 Pamphlet on the Tetrahedral Carbon Atom,Together with a New English Translation

J. H. van 't Hoff's 1874 Dutch pamphlet, in which he proposed the spatial arrangement of atoms in a molecule, is one of the most significant documents in the history of chemistry. This essay presents a new narrative of Van 't Hoff's early life and places the appearance of the pamphlet within the context of the 'second golden age' of Dutch science. We argue that the combination of the reformed educational system in The Netherlands, the emergence of graphical molecular modelling within the theoretical and practical culture of chemistry during the 1860s and 1870s, as well as Van 't Hoff's own personal research trajectory, formed the background to his unprecedented attribution of spatial meaning to the traditional concept of atomic 'arrangement'. We also present a new English translation of the pamphlet, for we have found that the existing translation, published by G. M. Richardson in 1901, contains many errors, changes and omissions. The new version offers a more accurate rendition in English of Van 't Hoff's style and argument.     

Induction of the synthesis of thymidine kinase by aldosterone in the kidney of the immature male rat

Summary Thymidine kinase activity was studied in kidneys from immature male rats after administration of aldosterone. Kinetic studies showed that the enzyme activity reached its maximum level 24 h after aldosterone injection. That increase was specific for aldosterone and could be related to the synthesis of new molecules of enzyme.     

振动方程的线性多步法数值求解

详细分析了工程中常用的振动问题数值解法Newmark及Wilson-θ法。并在此基础之上本文提出一种新的计算方法,即在计算t＋Δt时刻的状态时,不仅用到t时刻的各值,而且还将用到f-Δt,t-2Δt等各时刻的值。这样就可以提高数值积分时所用多项式的阶数,使得加速度在积分区间At内可以为时间的二次及三次函数;从而大大提高了解法的数值精度及解的稳定性,并且基本上不增加计算量。该法在数值计算上讲属于线性多步法。