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1.
Compressibility of a natural kyanite to 17.5 GPa 总被引：1，自引：0，他引：1
The compressional behaviour of a natural kyanite, (Al1.99Fe0.01)SiO5, has been investigated to about 17.5 GPa at 300 K using a diamond-anvil cell and synchrotron X-ray diffraction. The pressure–volume data fitted to the third-order Birch–Murnaghan equation of state (EoS) yield an isothermal bulk modulus (K0T) of 192 ± 6 GPa and pressure derivative () of 6 ± 1. When is fixed as 4, the derived K0T is 201 ± 2 GPa. These values are in excellent agreement with most experimental determinations in the literature. Consequently, it can be concluded that the compressibility of kyanite under high pressures has been accurately constrained. 相似文献
2.
The chemical and physical interactions between ingredients in composites play an important role in the improvement of service properties. The nucleophilic addition between polymer and isophoron diisocyanate molecules was monitored by FT-IR technique. The intensity loss of isocyanate absorption band in conjunction with the intensity growth of carboxyl absorption band indicates the progress of reaction. FT-IR spectroscopy was also adopted to examine the intermolecular hydrogen bonding of epoxy resin with silica as well as intramolecular one within polymer matrix. The vibration frequency of carboxyl group （-C=O） and hydroxyl group （-OH） shifts from 1736 to 1728 cm^-1and 3420 to 3414 cm^-1, respectively, indicating the occurrence of hydrogen bonding between -C=O and -OH. The vibration frequency of Si-OH moves from 3435 to 3414 cm^-1, suggesting the involvement of silica. Whereas the vibration frequency of pending -OH in polymer chain moves from 3435 to 3420 cm^-1 or 3414 cm^-1, proposing that this kind of interaction can also happen within polymer matrix. 相似文献
3.
We examined the effect of excessive Internet use on the time–frequency characteristic of the electroencephalogram by wavelet transformed and non-negative matrix factorization (NMF). The event-related potentials (ERP) of normal subjects and excessive Internet users were acquired using the oddball paradigm experiment. We applied the wavelet transformed and event-related spectral perturbation to ERP in order to extract the time–frequency values. The F-test statistics of time–frequency values were then decomposed into two components by NMF. Excessive Internet use resulted in a significant decrease in the P300 amplitudes (P < 0.05) and a significant increase in the P300 latency (P < 0.05) in all electrodes. The major effect of excessive Internet use on gamma oscillation occurred at 300 ms after stimuli at 40–50 Hz on the parietal central region. Thus, these data suggest that excessive Internet use affects information coding and integration in the brain. 相似文献
4.
Conclusions
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| (1) | Based on strict kinetics of chemical reactions, MCT-GC method can provide detailed information for generation of organic components. Through computer, we can obtain the yield of the total hydrocarbon or individual component for any geological period under given gmlogical conditions by combining MCT-GC data with geological perameters, and apply them to basin modeling, petroleum prediction, and so on. |
| (2) | n-Alkanes with high molecular weights were generated very early due to their low activation energies, e. g. fig. 3 shows that almost 98% of C24 has been generated within 20 Ma, while only 1% of C12 was generated. |
| (3) | Because equipment condition was limited, kinetics of methane, which is one of the most important component in petroleum exploration, is not discussed in this note. Our further work will focus on kinetics of methane through a modified MCT-GC set. |
5.
SHANG LinBo BI XianWu HU RuiZhong FAN WenLing 《科学通报(英文版)》2007,52(3):395-400
Using the solubility method, the solubility of CuCl2 in liquid-undersaturated HCl-bearing water vapor was investigated experimentally at temperatures of 330-370 ℃ and pressures of 4.2-10 MPa. The re-sults have shown that hydration could significantly enhance copper solubility and the concentrations of copper were positively correlated with PH2O. The solubility of copper in vapor phase increased with increasing PH2O at the constant temperature. CuCl2 was transported as hydrated species CuCl2(H2O)ngas in water vapor. The formation of complexes is proposed to be the result of the following reaction: CuCl2solid nH2Ogas = CuCl2 (H2O)ngas The hydration number n decreased slightly with increasing temperature. Statistical hydration numbers are 4.0, 3.6 and 3.3 at 330, 350 and 370 ℃ , respectively. 相似文献
6.
Conclusions
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| 1. | The eclogite dikes in low-greenschist facies epi-metamorphic volcaniclastic rocks in the Dabie Mountains areas show magma origin rather than tectonic melange or metamorphic origin. |
| 2. | Coesite and quartz pseudomorphs in the eclogite show that they were formed at the pressure of over 2.8 GPa and belong to ultrahigh pressure type. Therefore, there were high-pressure eclogite magma at deep crust depth. |
| 3. | From the country rock age of the low-grade metamorphic volcaniclastic rocks, we infer that the eclogite dikes were formed after the Sinian. |
7.
Conclusions
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| 1. | The high-temperature pyrolysis reaction of cellulose and organic matter have an optimal reaction condition: 95°C, 4–14 mg cellulose, and 15–30 min. |
| 2. | Under the optimal condition, the formed CO or CO2, and the sample have the same λ18O value. It is unnecessary to recover oxygen from CO. |
| 3. | The data are accurate and reliable, and the operation method is simple and economic. |
8.
Conclusion According to the calculated results for the dissociation mechanism of C4H4O+, we come to a conclusion as follows:
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| (1) | Reaction (1) of C3H4 + formation and reaction (2) of CH2CO+ formation are both the processes involving three steps. The first and the second step of the reactions are the same. |
| (2) | The first step of H-transfer of the two reactions are the rate determining step, whose UMP2//6-31G barrier is 280.5 kJ · mol−1, which is comparable to the experimental value. |
9.
Huang Benwen 《武汉大学学报:自然科学英文版》1997,2(4):405-410
The characterization ofA
5 is obtained through the method of calculation. The main result is described as the following:
Supported by the Natural Science Foundation of Hubei Province
Huang Benwen: born in Oct. 1948, Associate professor 相似文献
| 1) | The order ofA 5 is one, two, three or five. |
| 2) | The element ofA 5 is divided into five conjugate classes. |
| 3) | There are fifty and nine subgroup inA 5 and we can obtain one produce element in every subgroup. |
| 4) | There are nine conjugate classes in the subgroup ofA 5. |
10.
In this paper, we mainly study the relation of two cyclically reduced words w and w ′on the condi- tion they have the same trace polynomial (i.e., tr w= trw ′). By defining an equivalence relation through such operators on words as inverse, cyclically left shift, and mirror, it is straightforward to get that w ~ w ′ implies tr w = tr w ′. We show by a counter example that tr w = tr w ′ does not imply w ~ w ′. And in two special cases, we prove that tr w = tr w ′ if and only if w ~ w ′. 相似文献
11.
Conclusions
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| 1. | Over the past 8 000 years, notable changes in moist regime and temperature took place in Caohai District. The peat archives in this area recorded some hemispheric climatic events, such as three new ice ages and the Medieval Warm Period occurring in the northern hemisphere. This indicates that this area is sensitive to global changes. |
| 2. | Over the past 8 000 years, Caohai District is typical of the warm-moist—cool-dry climate. |
12.
Conclusions
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| 1. | Topologic analysis of representative Devonian graphoglyptids of China shows that a huge graphoglyptid clan can be grouped into three kinds of topologic configurations homeomorphic to line, tree and network, which correspond to foraging, probing feeding and the catching and feeding of constructing and inhabiting in anoxic, suboxic and dysoxic2) deep-water environments respectively. |
| 2. | It is well known that, in paleoecology and paleontology, morphologic features are bases of functional morphologic analysis of body and trace fossils, but, the features are not only Euclidean geometric, but also topologic and fractal geometric. In terms of the topologic graphoglyptids homeomorphic to line, tree and network, the functional morphologic analysis based on topologic configuration can reveal trace producer’ s ethology and ecological function mysteries contained in trace fossils from new aspects. |
| 3. | A functional topologic morphologic analysis first can get rid of interference of original biogenic traces to be subjected to compacting, diagenesis and deformation. In addition, it can simplify existing classification and naming system of ichnology, enrich and develop the theory and methodology of a functional morphologic analysis. |
13.
The differences of thermal conduction and its temperature-varying track of the heat source body at various structural environments have been studied. Hypothetically , geologic heat source body is cut successively into several segregative bodies with a fixed cubage . With the segmented number increasing , the conductive surface area of heat source body begins to get larger, which separately is similar to the heat geologic body in different tectonic zones that
has a various enclosed coefficient . Finite-element simulation result shows that
the thermal conduction speed of spreading from the heat source body to its wall rock is slow→higher→ highest, when heat source bodies are situated respectively at compressive, shear and tensile deformation zones, corresponding rates of their temperature drop are low→ higher→ highest .
Research indicates that the temperature ' s dropping rate of heat source body has an inverse relationship with enclosed coefficient η for different structural zones . This result can explain the tectono-physicochemical reason of magmatite evolution and its. difference . 相似文献
14.
15.
Conclusions
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| 1) | Using conventional deposition techniques of heating or e-beam evaporation, the effect of the substrate’s temperature cannot be neglected. If the substrate temperature is not uniform, the uniformity of the film thickness and the film’s composition may change. But with magnetron sputtering deposition, the effect of the substrate temperature is almost absent. |
| 2) | It is known that various of evaporation depositions, such as ion sputtering deposition and other physical vapor depositions can hardly be used to prepare large-area uniform films. At present, magnetron sputtering deposition is the best preparation method of large-area uniform films. |
| 3) | With the quartz crystal monitor of film thickness and suitably designed film structures, films of less than 0.2% reflectivity in visible region can be obtained. |
16.
Conclusion
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| 1 | The dispersion capacity of MoO3 supported on CeO2 is 0.81 rnmo1/100 m2. For samples with MoO3 content is below the dispersion capacity, Mo6+ ions exist in the surface vacancies to form the surface Mo species, and the highly dispersed Mo6+ cations are coordinated by 7 oxygen ions based on the assumption that the CeO2(111) plane is preferentially exposed. |
| 2 | The differences of the dispersions between MoO3 on CeO2 and MoO3on ZnO-modified CeO2 indicate that the surface vacancies play an important role in the dispersion of MoO3. |
17.
Conclusions
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| 1. | It is a successful attempt to test and study O-Si stable isotopic composition of SiO2 shells of radiolarian of sediment core below the depth of 5 000 m in the Pacific Ocean because of lacking of calcium shells below CCD in ocean. The distribution and variation, from 21.2 X 10−3 to 34.5 × 10−3 for δ18OSMOW and from 0.2 × 10−3 to 1.2 × 10−3 for δ30SiNBS-28, have certain link with and difference from those of other oceanic organisms. |
| 2. | The relationship between δ18O and δ30Si values indicates obviously that the humeric distribution of core samples from No. 1787 station shows two groups separated by the depth of 160 cm. This distribution is also recorded by two kinds of isotopic curves (fig. 2(a), (b)), reflecting the evolutional difference of oceanic environment and stratigraphic sequence between the upper and lower layers separated by the depth of 160 cm. |
| 3. | Through a correlation of δ18O values, the core from No. 1787 station shows that since 27 Ma, the Pacific Ocean has experienced 7 cold/warm changes, accompanied by the frequent variations of global ice volume and sea level. |
18.
Yanzhong Zhang 《科学通报(英文版)》1997,42(14):1218-1222
Conclusions
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| (1) | The newly developed nanocrystalline Fe72 Cu1Nb2V2Sil4 B9 and Fe72Cu1NblMo1-V2Si14B9 alloy still show the superior synthetical magnetic properties quite comparable with those of the early developed and typical Fe-Cu-Nb-Si-B alloys. Their cost has been reduced, the ductility of their amorphous ribbons is much better than that of Fe-Cu-Nb-Si-B alloys, and their ribbons can be folded back without brittleness. |
| (2) | In the range off = 20–2000 kHz and Bm = 0.05-0.6 T, the dependences of core loss on frequency and amplitude flux density can be expressed asPoc B2 mfn,n = 1.6-1.7. |
| (3) | In the range of f= 20–2000 kHz and (B m f) = (15−30) × 103 T·Hz, the approximate expression 1nP = [a(Bm,f) +b] (lnf)-n is tenable, wheren =0.2-0.3, and botha andb are constant. |
| (4) | The newly developed nanocrystalline alloys have been used in switching mode power supply with larger output power, unipolarity pulse transformer and precision current mutual inductor and clearly shown advantage. |
19.
HE Zhenya CHEN Hua 《武汉大学学报:自然科学英文版》2007,12(3):391-394
We consider the following non-linear elliptic equation △u＋ f（x,u）=0,x∈K on fractal domains with zero-Dirichlet boundary conditions, where K is self-similar fractal, △ is the Laplacian defined on K. f（x, t） is asymptotically linear as t→ ∞. We get the non-trivial and non-negative solution by using Mountain Pass lemma. 相似文献
20.
Weiming Xu 《科学通报(英文版)》1997,42(4):282-282
Conclusions The results we obtained in the present investigations can be summarized as follows.
It can be concluded that the short-range chemical order plays a dominant role in this kind of magnetic order in this alloy.
Our results are favorable for the first picture given above which explains the mechanism of re-entrant spin glass behavior. 相似文献
| 1. | The sample is magnetically heterogeneous. Above Tc, the PM phase is dominant in the alloy. But in this temperature range, the M-Ba plot is still curved andthe external field dependence of the internal field was also observed in the in-field M?ssbauer measurements. It implies that there are magnetically coupled clusters in the sample. These clusters may behave superparamagnetically in the alloy. So they did not cause the change of the line width of the M?ssbauer spectra without external field. The magnetic moments of the clusters can be polarized by external field, which causes the curvature of M-Ba plot and the external field dependence of the internal field. |
| 2. | Below Tc, some PM phase persists down to 50 K at least. The clusters with very low Tc or even coupled antiferromagnetically at low temperatures are responsible for the PM phase in this temperature range. |
| 3. | At 50 K, the FM phase is dominant whereas some magnetic moments are coupled antiferromagnetically in the alloy. |
| 4. | At a freezing temperature of about 25 K, the re-entrant spin glass behavior can be observed in the alloy. |