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Wave propagation and energy dissipation in viscoelastic granular media

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Journal of Central South university 2001年第3期13卷 185-188页

作者： SUN Ye-zhi 1, WU Ai-xiang 1, LI Jian-hua 1,2.(1. College of Resources, Environment and Civil Engineering, Central South unive rsity, Changsha 410083. China 2. The 5th Building Company in Guangdong Province, Shaoguan 512.2., China) College of Resources Environment and Civil Engineering Central South University Changsha China The 5th Building Company in Guangdong Province Shaoguan China

In terms of viscoelasticity, the relevant theory of wave i n granular media is analyzed in this paper. Under the conditions of slight deforma tion of granules, wave equation, complex number expressions of propagation vecto r and attenuation vector, attenuation coefficient expressions of longitudinal wa ve and transverse wave, etc, are analyzed and deduced. The expressions of attenu ation coefficients of viscoelastic longitudinal wave and transverse wave show th a t the attenuation of wave is related to frequency. The higher the frequency is, the more the attenuation is, which is tested by the laboratory experiment. In a ddi tion, the energy dissipation is related to the higher frequency wave that is abs orbed by granular media. The friction amongst granular media also increase the e nergy dissipation. During the flowing situation the expression of transmission f actor of energy shows that the granular density difference is the key factor whi ch leads to the attenuation of vibrating energy. This has been proved by the exp eriment results.

关键词： viscoelastic granular media wave motion energy dissipation flowing situation

International Transferring Trend in Manufacturing Industry

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厦门大学学报（自然科学版） 2002年第S1期41卷 222-223页

作者： ZHAO Xin-jun 1, XU Li-hui 2.(1. School of Mechanical Engineering and Automation, Northeastern unive rsity, Shenyang 110004, China 2. School of Business Administration, Northea stern university, Shenyang 110004, China)

This paper addressed the international transferring t endency of manufacturing industry one by one as follows: (1) The developed count ries realize manufacturing industry structure upgrade reling on worldwide tr ansference not only domestic transference. On one hand, the TNCs make cross-inv estments, transnational merger & acquisition so as to achieve the optimum colloc ation of R&D resources, and obtain innovation in knowledge and technology. On th e other hand, the developed countries transfer labor and resource intensive indu stry as well as the labor-intensive link of the production chain in highly tech nology industry to the developing countries, to make their industrial structure escalation. (2. The adjustment and upgrade of manufacturing industry presents "m ulti-step type". First, the object of international transference substitutes th e capital-intensive industry and maturing industry with complicate technique fo r the industry with labor-intensive, simple technique or higher pollution, or s ubstitutes non-core complex technological procedure and parts and components fo r assembly in manufacturing process. Secondly, technology transference forms "br ain-hand and foot" pattern, i.e. the developed countries are increasingly p aying more and more attention to the research and control of core technology, th us transferring simple technique and labor-intensive procedure in higher scienc e and technology. Thirdly, the developed countries begins to transfer both capit al and technology intensive production, as well as transfer certain procedures i n higher technology production process to a few developing countries, even t o transfer parts of R & D to developing countries. (3. TNCs promote the global m anufacturing network (GMN) by recombination and transfer. TNCs organize producti on, trade, technological research and transference through foreign direct invest ment (FDI) all over the world, as a result, GMN makes the national competence no longer depend on absolu

关键词： manufacturing industry international transferrin g tendency

Study on the Friction Coefficient in Grinding

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厦门大学学报（自然科学版） 2002年第S1期41卷 119-120页

作者： CAI Guang-qi 1, FENG Bao-fu 1, JIN Tan 2. GONG Ya-dong 1 (1. School of Mechanical Engineering & Automation, Northeastern unive rsity, Shenyang 110004, China 2. School of Industrial & Manufacturing Science, Cranfield university, Cranfield, Bedfordshire, UK)

The friction between the abrasive grains and workpi ec e is a crutial factor determining the main grinding output. Few studies have bee n carried out investigating the values of the friction coefficient in grinding, due to the difficulty of direct measurement. In this paper, a mathematical model of the friction coefficient in grinding has been established with the aid of a new grinding parameter C ge, which has close relations to wheel wear rate Z s, metal removal rate Z w, specific energy u and grinding force ratio λ(λ=F n/F t). By monitoring the process forces, C ge can be obtained and used easily for different grinding methods. Heavy grinding with different wheels and also single-grit grinding tests have been conducted for various work materials. The friction coefficients under different grinding conditions have been obtaine d using the model and the experimental results. For most materials tested in pap er, the friction coefficients decrease with the grinding speed. The friction coe fficients in single-grit grinding are 0.61～0.84 at the speed of 0.02. m/s, and 0.09～0.3. at the speed of 67～12. m/s. In single-grit grinding for 45 # a nd 2.Cr steels, the friction coefficients decrease with the increase of the grindi ng speed while below a critical speed, and increase slightly with the increase o f grinding speed while above the critical grinding speed. Owing probably to the high surface temperature caused by high power consumption and dry condition, the friction coefficients in heavy grinding are 0.09～0.19, distinctly lower than t h ose of single-grit grinding, and also lower than those of ordinary grinding. Du e to the softening of the metals, the friction coefficients in heavy grinding un der dry condition are lower than that in wet condition. Owing probably to the di fference of hardness and roughness, while using different types of wheel and abr asive, the friction coefficients for the same work material changes even at same grinding speed. The work materials a

关键词： grinding friction coefficient model

Potash-rich volcanic rocks and lamprophyres in western Shandong Province:^(40)Ar-^(3.)Ar dating and source tracing

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Chinese Science Bulletin 2002年第2期47卷 91-99页

作者： QIU Jiansheng, XU Xisheng & LO Ching-HuaState Key Laboratory of Mineral Deposit Research of Nanjing university, Nanjing 2.0093. China Department of Earth Sciences, Nanjing university, Nanjing 2.0093. China Department of geology, Taiwan unive State Key Laboratory of Mineral Deposit Research of Nanjing university Nanjing China Department of Earth Sciences Nanjing University Nanjing China Department of geology Taiwan University Taibei China

Highly precise 40Ar-3.Ar dating results demon-strate that the ages of potash-rich volcanic rocks in western Shandong Province are 114.7-12..3.Ma, and that of the lamprophyres is 119.6 Ma. The potash-rich volcanic rocks have relatively high (87Sr/86Sr)i ratios ( 0.708715-0.711418) and distinctly negative εNd values ( -11.47--17.54), and are enriched in radiogenic lead (2.6Pb/2.4Pb=17.3.1-17.62., 2.7Pb/2.4Pb=15.52.-15.53., 2.8Pb/2.4Pb=3..563.3..684). Similarly, the lamprophyres also have quite low εNd values (-11.57 - -19.64). Based on the fact that the Sr, Nd and Pb isotopic compositions of potash-rich volcanic rocks are very consistent with that of the clinopyroxene separates, and by integrating comprehensive analyses of their tectonic settings, and extensive comparisons of the Sr, Nd isotopic composi-tions with that of the related simultaneous rocks, it is con-cluded that the potash-rich volcanic rocks and lamprophyres in western Shandong Province were most possibly derived from the partial melting

关键词： potash-rich volcanic rocks lamprophyres 40Ar-3.Ar dating Sr-Nd-Pb isotope tracing western Shandong Province.

SEDIMENTARY PROCESS OF THE CENOZOIC BASIN AND ITS RESPONSE TO THE SLIP-HISTORY OF THE ALTYN TAGH FAULT, NW CHINA

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地学前缘 2000年第S1期7卷 245-246页

作者： Chen Zhengle 1, Zhang Yueqiao 1, Chen Xuanhua 1,Wang Xiaofeng 1, Z.Washburn 2.J.Arrowsmith 2.WT5,5”BX](1 The Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081,China 2.Department of geology, Arizona State unive

The NEE\|striking Altyn Tagh Fault (ATF) has been well known as one major point to know the growth history of the Tibetan plateau. Lots of investigations done since 1970’s were mostly focus on active features, particularly on determining slip, slip rate and their distribution along the fault. However, Cenozoic slip\|history of this fault remains poorly understood, and the age of initiation and total offset are controversial. Several Cenozoic sedimentary basins develop in Suo’erkulinan to Mangya regions (Fig.1). Their sedimentary processes are closely related with the ATF. The studies of the Neogene sedimentary sequences and the reconstruction of the paleo\|geography are essential to establish the displacement history of the fault during Late *** at the southern side of the ATF, the Suo’erkulinan basin consists of more than 600\|meter\|thick Pliocene Shizigou Formation below and about 12.\|meter\|thick Early to Middle Pleistocene Qigequan Formation above according to the 1∶2.0000 geological map by Xinjiang Province. An obvious erosional surface can be seen on the top of the lower sequence. Sediments in the Shizigou Formation are characterized by 400\|meter\|thick yellow to red cobble\|sized conglomerates in the bottom, up\|grading to sandstones and grey\|green mudstones. This indicated that the sedimentary facies changed from alluvial fan to fluvial fan and sediments became more and more mature. The upper sequence, the Qigequan Formation, corresponds to an alluvial facies series composed of yellow to white cobble\|sized conglomerates intercalated with lenticular sandstones. Paleo\|current indicators showed that the Shizhigou conglomeratic series were sourced from northwest. Well\|developed syn\|sedimentary faults, normal faults mostly inherited from syn\|sedimentary faults, and some striation lineations on the surface indicated transtensional tectonic environment of the strike\|slip faulting.

关键词： Altyn Tagh fault Cenozoic basins sedimentary process slip\| history reconstruction of the paleo\|geography

The frequency estimation of harmonic signals embedded in multiplicative and additive noise

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Chinese Journal of Acoustics 2002年第3期21卷 271-277页

作者： FAN Yangyu1,2.TAO Baoqi1 XIONG Ke1 SHANG Jiuhao2.SUN Jincai3.LI Yaan3.1 The key Laboratory for Smart Materials and Structures, Nanjing {2.rsity of Aeronautics andAstronautics Nanjing 2.0016)(2.Mechanical & Electrical Engineering College, northwest unive

A method to separate a harmonic signal from multiplicative and additive noises is proposed. The method is to square the signal x(t), which consists of a harmonic signal embedded in multiplicative and additive noises, to form another signal y(t) = x2.t)-E[x2.t)]. After y(t) having been gotten, the Fourier transform is imposed on it. Because the information of x(t) (especially about frequency) is included in y(t), the frequency of x(t) can be estimated from the power spectrum of y(t). According to the simulation, under the condition where frequencies divided by resolution dω are integer, the maximum relative error of estimated frequencies is less than 0.4% when the signal-to-noise ratio (SNR) is greater than -2.0}dB. If frequencies divided by resolution dω are not integer, the maximum relative error will be less than 2.9%. But it is still small in terms of engineering.

关键词： The frequency estimation of harmonic signals embedded in multiplicative and additive noise

A　New　Mid　Early　Pleistocene　Mammalian　FaunaDiscovered　in　Choukoutien，China　and　Its　Application　in　Biostratigraphy

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Journal of Earth Science 1995年第1期14卷 41-47,120页

作者： Cheng Jie(Department of geology and Mineral Resources, China university of Geosciences,Beijing 10008{2.Cao Boxun(Faculty of Earth Sciences, China university of Geosciences,Wuhan 4{2.074)Tian MingZhong(Department of geology and Mineral Resources, China unive

This paper deals with a new Early Pleistocene micromammalian fauna found in Choukonden (Zhoukoudian) and its application in *** new locality (east cave ), discovered in 1985,is located on the north slope of the Taipingshan Hill, about 2.km northeast of the Loc.1 in Choukoutien and is about 140-150m in altitude. At this locality,abundant fossil mammals are found in thick cave-fissure deposit. This fauna comprises 3.mammalian taxa. Based on the comparison of the fauna, as Well as the sporo-pollen, climate events and paleomagnetic polarity section with those in other areas,we come to the conclusion that the sediments (Taipingshan Formation) in east cave were formed during the Period about from 1.67 Ma B. P. to 0.97 Ma B. P., and the fauna is about 1.2. Ma B. P. in ags.

关键词： mid Early Pleistocene micromammalian fauna biostratigraphy Choukoutien.

A New Phenylpropanoid Glycoside: Serratumoside A from Clerodendrum serratum

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Chinese Chemical Letters 2000年第4期11卷 323-326页

作者： Hui YANG~(1,2. Ai Jun HOU~1 Shuang xi MEI~1 Li Yan PENG~ Han Dong SUN~1 (1 Laboratory of Phytochemistry, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 6502.4) 2.hemistry Department, College of Life Science and Chemistry, Yunnan unive Laboratory of Phytochemistry Kunming Institute of Botany Chinese Academy of Sciences Kunming 650204 China Chemistry Department Coll. of Life Science and Chemistry Yunnan University Kunming 650091 China

A new phenylpropanoid glycoside, serratumoside A, was isolated from the aerial parts of Clerodendrum serratum var. amplexifolium Moldenke. Its structure was determined by spectral and chemical methods.

关键词： Clerodendrum serratum Verbenaceae phenylpropanoid glycoside serratumoside A

Effects of MoS_2.on mechanical and tribological properties of NiCr-based alloys

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中国有色金属学会会刊：英文版 2000年第3期10卷 328-327,329-331页

作者： XIONG Dang sheng(熊党生) 1, PENG Chao qun(彭超群) 2. LIU Jin long(刘金龙) 1 1. College of Mechanical Engineering, China university of Mining and Technology, Xuzhou 2.1008, P.R.China 2. State Key Lab for Powder Metallurgy, Central South unive 中南工业大学粉末冶金国家重点实验室湖南长沙

Ni Cr based alloys with a wide temperature range self lubrication were made by hot pressing the mixture powder of alloyed Ni Cr powder, elemental Mo, Al, Ti and B powders and MoS 2.powder. The mechanical and tribological properties of these alloys when rubbing with Al 2. 3.ceramics and W18Cr4V high speed steel were measured in the temperature range of 2.～700 ℃, and the mechanisms of self lubrication and wear resistance were studied. The results showed that the alloy containing 10% MoS 2.has the best combination of mechanical properties, antifriction and wear resistance. Over a wide temperature range from 2. ℃ to 700 ℃, when rubbing with Al 2. 3. its friction coefficient and wear rate are 0.19～0.3.and (1.1～1.5)10 -14 m 3.(N·m), respectively; when rubbing with the high speed steel, those values are 0.18 ～ 0.2. and (0.6～3.2.×10 -15 m 3.(N·m), respectively.

关键词： Ni Cr based alloys molybdenum disulfide self lubrication tribological properties