Showing papers by "Nanjing University published in 1992"

Diamond from the Dabie Shan Metamorphic Rocks and Its Implication for Tectonic Setting

Abstract: Diamond occurs in ultrahigh pressure metamorphic rocks from Dabie Shan, Anhui Province, eastern China. Diamond-bearing rocks include eclogite, gamet-pyroxenite, and jadeitite. Diamond occurs in a mineral assemblage with coesite and jadeite. The diamonds and diamondiferous rocks of Dabie Shan are interpreted to be the products of ultrahigh pressure metamorphism in the underthrust basement of the Yangtze continental plate during the early Mesozoic, at greater than 4.0 gigapascals and 900°C. This interpretation is based on the distribution of rock units, the stability field of diamond, and isotopic data indicating a crustal origin for the rocks. Most diamonds occur as euhedral inclusions in garnets and are 10 to 60 micrometers across, although some are up to 700 micrometers across.

Design of metal-complex magnets. Syntheses and magnetic properties of mixed-metal assemblies {NBu4[MCr(ox)3]}x (NBu4+ = tetra(n-butyl)ammonium ion; ox2- = oxalate ion; M = Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+)

Abstract: The reaction of K 3 [Cr(ox) 3 ].3H 2 O, a metal(II) salt, and tetra(n-butyl)ammonium bromide in the molar ratio of 1:1:1.5 in water at room temperature afforded a series of mixed-metal assemblies with the formula {NBu 4 [MCr(ox) 3 ]} x (M=Mn 2+ , Fe 2+ , Co 2+ , Ni 2+ , Cu 2+ , Zn 2+ ).

Surface interaction model ofγ-alumina-supported metal oxides

Abstract: An incorporation model has been proposed and used to discuss the interaction between various metal oxides and γ-alumina. The dispersion capacities of various metal oxides are predicted and the surface hydroxyl group density on γ-alumina estimated, based on the assumption that the (110) plane is preferentially exposed on the surface of γ-alumina. These results are in good agreement with the available experimental data.

Fibonacci numbers and Fermat's last theorem

Abstract: numbers. As applications we obtain a new formula for the Fibonacci quotient Fp−( 5 p )/p and a criterion for the relation p |F(p−1)/4 (if p ≡ 1 (mod 4)), where p 6= 5 is an odd prime. We also prove that the affirmative answer to Wall’s question implies the first case of FLT (Fermat’s last theorem); from this it follows that the first case of FLT holds for those exponents which are (odd) Fibonacci primes or Lucas primes.

Internal friction and dielectric loss related to domain walls.

Abstract: The internal friction in potassium dihydrogen phosphate (KDP) crystal and the dielectric loss in KDP and triglycine sulfate (TGS) crystals are measured near T c in the kHz frequency range. An internal-friction peak (P M2 ) and a dielectric loss peak (P D2 ) appear at about several degrees below T c , which are found to be associated with the viscous movement of domain walls

Plasma polymerization of organosiloxanes

Abstract: Plasma polymerization of disiloxanes containing various functional groups—hexamethyldisiloxane (HMDSO), tetramethyl-1,3-bis(chloromethyl)-disiloxane (CMDSO), tetramethyl-1,3-bis(hydroxylbutyl)-disiloxane (HBDSO), and tetramethyl-1,3-bis(amino propyl)-disiloxane (APDSO)— was carried out using an inductively coupled electrodeless glow discharge. The monomer polymerization kinetics and the distribution of chemical species deposited showed that monomer reactivity varied among the different siloxanes. Monomers of APDSO and CMDSO possessed higher rates of polymerization. Polymer IR spectra and ESCA analyses indicated that the chemical structures of plasma-polymerized products of HMDSO, HBDSO, and CMDSO resembled that of crosslinked polydimethylsiloxane. The polar hydroxyl and chlorine functionality in the HBDSO and CMDSO monomers was not present in the deposited films. In contrast, the polymerized product of APDSO retained amino functionality and also formed new Si–H bonds.

Relationship between climatic change and the nomadic southward migrations in eastern Asia during historical times

Abstract: On the basis of data obtained from ancient Chinese chronicles, this study has established time series of southward and eastward migrations of the nomad people in the southern Mongolian grasslands and eastern central Asia from 190 B.C. to A.D. 1880 and found that there is a close relationship between climatic change and the migrations. We hypothesized that such a climate-migration relationship perhaps resulted from both livestock failure of the nomad people and crop failure of the Han Chinese during cold and/or dry climatic periods.

Suspended sediment transport processes on tidal mud flat in Jiangsu Province, China

Abstract: The intertidal mud flat in Jiangsu Province is an open or semi-open tidal flat, with a moderately-high tidal range. This paper analyses characteristics of tidal current and suspended sediment concentration on the intertidal flat. Comparison is then made with characteristics on the intertidal flat of the Dutch coastline, Wadden Sea and similar areas. The suitability and limitations of applying the ‘lag’ mechanism to an open or semi-open macrotidal flat is examined. Residual water and sediment circulation on the intertidal flat show they can be divided into a series of longshore cells, which form individual hydrodynamical sedimentary units.

The value of the Ramsey number R (3,8)

Abstract: The Ramsey number R(3, 8) can be defined as the least number n such that every graph on n vertices contains either a triangle or an independent set of size 8. With the help of a substantial amount of computation, we prove that R(3, 8)=28.

Measurement of J/ psi and psi ' production in 300-GeV/c proton, antiproton, and pi +/- interactions with nuclei.

Abstract: Hadroproduction of the {ital J}/{psi} and {psi}{prime} states has been studied in 300-GeV/{ital c} proton, antiproton, and {pi}{sup {plus minus}}Li interactions Both total and differential cross sections in {ital x}{sub {ital F}} and {ital p}{sub {ital T}} have been measured for the {ital J}/{psi} for the {pi}{sup {plus minus}}, proton, and antiproton interactions The ratio of {psi}{prime} to {ital J}/{psi} production has been determined for the four types of beam particles

Theory of Faraday rotation and susceptibility of rare-earth trifluorides.

Abstract: A theoretical investigation on the magneto-optical and magnetic properties of light rare-earth trifluorides ${\mathrm{CeF}}_{3}$, ${\mathrm{PrF}}_{3}$, and ${\mathrm{NdF}}_{3}$ is presented. The 0.6328-\ensuremath{\mu}m-wavelength Faraday rotation and susceptibility of these compounds in the temperature range 40\char21{}300 K have been calculated based on the quantum theory. The result shows that in the visible region the Faraday rotation is mainly caused by the intraionic electric-dipole transitions between the 4${\mathit{f}}^{\mathit{n}}$ and 4${\mathit{f}}^{\mathit{n}\mathrm{\ensuremath{-}}1}$5d configurations of rare-earth ions. The Faraday rotation and susceptibility of these compounds depend greatly on the splitting of the ground multiplet of the rare-earth ions in crystal fields. For non-Kramers ${\mathrm{Pr}}^{3+}$ ions in ${\mathrm{PrF}}_{3}$, the lowest crystal-field state is a singlet, so at very low temperature the behavior of the Verdet constant and susceptibility of ${\mathrm{PrF}}_{3}$ is different from ${\mathrm{CeF}}_{3}$ and ${\mathrm{NdF}}_{3}$. For ${\mathrm{CeF}}_{3}$, the mixed-valent behavior of Ce ions must be taken into account.

The semicircular shell of CTB 109

Abstract: The radio and X-ray images of the supernova remnant CTB 109 have the morphology of a semicircular shell. It is shown that such a structure is a natural result of a supernova explosion that occurred 3,000 yr ago near an interface between the diffuse interstellar medium and a dense molecular cloud. The calculated X-ray, infrared, and radio fluxes agree fairly well with the observed values.

Cosmparative study of the ordering of B‐S ite cations in Pb2ScTaO6 and Pb2ScNbO6 perovskites

Abstract: A comparative study of as-g rown Pb2ScTaO6 and Pb2ScNbO6 crystals obtained under similar conditions is made by X-r ay and electron diffraction and by HREM at room temperature. From this study it can be concluded that: (i) the average distribution of atoms gives a cubic unit cell for both compounds though the study is conducted at a temperature close to Tc for PST, and lower than Tc for PSN; (ii) PST and PSN present the classical {111}-type ordering and PST material has always a higher degree of ordering than PSN when they are prepared under similar conditions; (iii) small domains of {110}-type ordering are observed in these two compounds leading to supplementary reflections, even by X-r ay diffraction in the case of PSN. Une etude comparative des perovskites Pb2ScTaO6 et Pb2ScNbO6 non recuites et obtenues dans des conditions semblables a ete realisee a temperature ambiante par diffraction de rayons X et d'electrons, ainsi que par MEHR. D'apres cette etude nous pouvons deduire que: (i) La distribution atomique moyenne conduit a un reseau cristallin de maille cubique pour les deux composes, bien que l'etude soit realisee a une temperature proche de Tc pour PST et inferieure a Tc pour PSN. (ii) PST et PSN presentent un ordre de type {111}, mais le degre d'ordre pour PST est toujours superieur a celui de PSN (PST et PSN etant prepares dans les měmes conditions). (iii) De petits domaines d'ordre de type {110} apparaissent dans ces deux composes conduisant a des reflexions supplementaires, observees měme par diffraction de rayons X dans le cas de PSN.

On exactlym times covers

Abstract: In this paper it is shown that if every integer is covered bya 1+n 1ℤ,…,a k +n k ℤ exactlym times then for eachn=1,…,m there exist at least ( ) subsetsI of {1,…k} such that ∑ i ∈ I 1/n i equalsn. The bound ( ) is best possible.

Human impact on coastal landform and sedimentation

Abstract: Man is an important geological agent. This paper documents a unique case of the dominating role of man in coastal evolution and hydrological changes in North Jiangsu province. Owing to human breaching of dikes on the Lower Yellow River in 1128, a large anthropogenic delta — the Abandoned Yellow River Delta was formed. Its rapid growth and quick decay over a period of 400 years further illustrates the overwhelming influence of human activity in triggering coastal changes. Man's diversion of the Yellow River to Jiangsu has also resulted in a dramatic change of the drainage pattern and hydrology of North Jiagsu. The Huai-He, a major river in central China, was changed from an independent river draining into the sea in the 11th century, to a tributary of the Yangtze river since the 17th century. At the same time, Hongze lake was enlarged from a small lake to one of the largest fresh water lakes in the country.

Selective inhibition of normal murine myelopoiesis "in vitro" by a Hox 2.3 antisense oligodeoxynucleotide.

Abstract: Multiple homeobox genes are expressed in haematopoietic cell lineages and their expression is cell-type specific. Thus we hypothesized that certain homeobox genes may play an important role in the process of haematopoiesis. To prove that issue, normal murine bone marrow cells were stimulated with appropriate Colony Stimulating Factors in the presence of mouse homeobox gene (Hox 2.3) sense or antisense oligodeoxynucleotides and the effects on the haematopoietic colony formation were examined. Treatment of the cells to Hox 2.3 antisense oligodeoxynucleotides led to a selective inhibition of myeloid colony formation, both in size and in numbers, but without significant effect on erythroid and megakaryocytic haematopoiesis. Exposure to Hox 2.3 sense oligodeoxynucleotides (no-oligomers), had no such effect. It was further showed that inhibition of myelopoiesis by Hox 2.3 antisense oligodeoxynucleotides was dependent on the differentiation stage of target cells. These findings demonstrated that Hox 2.3 gene plays a critical role in regulating normal murine myelopoiesis.

Analytical solutions to the four post-Newtonian effects in a near-Earth satellite orbit

Abstract: On the basis of the results by Huang et al. (1990), this paper further discusses and analyses the four post-Newtonian effects in a near-Earth satellite orbit: the Schwarzschild solution, the post-Newtonian effects of the geodesic precession, the Lense-Thirring precession and the oblateness of the Earth. A full analytical solution to the effects including their direct perturbations and mixed perturbations due to the Newtonian oblateness (J2) perturbation and the Schwarzschild solution is obtained using the quasi-mean orbital element method analogous to the Kozai's mean orbital element one. Some perturbation properties of the post-Newtonian effects are revealed. The results obtained not only can provide a sound scientific basis for the precise determination of a man-made satellite orbit but also is suitable for similar mechanics systems, such as the motions of planets, asteroids and natural satellites.

Love numbers of the moon and of the terrestrial planets

Abstract: In the IERS Standards (1989), for the Moon the adopted value of the tide Love number, k 2, is equal to 0.0222. In this paper using the latest geodetic parameters of the Moon a group of internal structure models are constructed for this celestial body (see Table V), then the dependence of the Moon's core size on calculated value of k 2 is explored. The obtained results indicate that the second degree Love number, k 2 = 0.02664, of the lunar model 91–04 is near its observed value (0.027 ± 0.006). This implies that the Moon may possess an outer core of 660 km radius and of 300 kbar mean rigidity. With the same method the static Love numbers from degree 2 to 30 are computed for the terrestrial planets — Mercury, Venus, and Mars (see Table VII), and the influence of some parameters (such as the rigidity) of the outer core on low degree Love numbers is discussed. Finally, the likely range of the second degree Love numbers is determined for the terrestrial planets (see Table XI). It seems that if low degree Love numbers of a terrestrial planet can be detected in the future space explorations, there is some possibility to improve the planetary internal structure model. For example, as soon as space techniques yield an observed value of k 2 > 0.10 for Mercury, there will be reason to anticipate that a partly melted iron core exists in this planet.