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1.
CHEN MengJin NING Ning HU GuoYi LI Jian 《科学通报(英文版)》2007,52(A01):103-112
According to organic geochemistry and organic petrology, the hydrocarbon sources in Pingliang Formation, W. Ordos basin, are systematically evaluated. The organic abundance of hydrocarbon source in this research is higher in the upper part of profiles than in the low, and more in mudstone than in carbonate. Most of organic matters become sapropelic, and few are humic-sapropelic in the regions of Shibangou and Zhuzisan. According to stable isotopes of carbon and oxygen in carbonate rock, boron index and ratios of elements, palaeo-salinity and sedimentary velocity are calculated. The two factors of paleao-salinity and sediment velocity, which control the distribution of organic matters, are discussed. Good relationship is found between water salinity and abundance of organic matter; in contrast, poor correlation is observed between salinity and types of organic matters. The relative sediment velocity in the research regions is also related with organic abundance and types. A low sediment velocity would lead to high abundance and good type of organic matters, and vice versa. 相似文献
2.
Effect of High-Frequency Vertical Vibration of Track on Formation and Evolution of Corrugations 总被引:1,自引:0,他引:1
The effect of high-frequency curved track vibrations in the vertical direction on the formation and development of rail corrugation was analyzed. Kalker‘s non-Hertzian rolling contact theory was modified and used to calculate the frictional work density on the contact area of the wheel and rail in rolling when a wheelset is steadily curving. The material loss unit area was assumed to be proportional to the frictional work density to determine the wear depth of the contact surface of the rail. The combined influences of the corrugation and the coupled dynamics of the railway vehicle and track were taken into consideration in the numerical simulation. For simplicity, the model considered one fourth of freight car without lateral motion,namely, a wheelset and the equivalent one fourth freight car body above it. The Euler beam was used to model the rails with the track structure under the rails replaced with equivalent springs, dumpers, and mass bodies. The numerical results show that the high-frequency track vibration causes formation of the initial corrugation on the smooth contact surface of the rail when a wheelset is steadily curving. The corrugation wave,length depends on the frequencies and the rolling speed of the wheelset. The vibration frequencies also affect the depth and increase the corrugation. 相似文献
3.
Characteristics of hydrocarbon sources and controlling factors of their formation in Pingliang Formation,West Ordos Basin 总被引:1,自引:0,他引:1
《科学通报(英文版)》2007,52(Z1)
According to organic geochemistry and organic petrology, the hydrocarbon sources in Pingliang Formation, W. Ordos basin, are systematically evaluated. The organic abundance of hydrocarbon source in this research is higher in the upper part of profiles than in the low, and more in mudstone than in carbonate. Most of organic matters become sapropelic, and few are humic-sapropelic in the regions of Shibangou and Zhuzisan. According to stable isotopes of carbon and oxygen in carbonate rock, boron index and ratios of elements, palaeo-salinity and sedimentary velocity are calculated. The two factors of paleao-salinity and sediment velocity, which control the distribution of organic matters, are discussed. Good relationship is found between water salinity and abundance of organic matter; in contrast, poor correlation is observed between salinity and types of organic matters. The relative sediment velocity in the research regions is also related with organic abundance and types. A low sediment velocity would lead to high abundance and good type of organic matters, and vice versa. 相似文献
4.
GUO Hong-tao XU Fei GAO Nan ZHOU Xiao-hai~ DONG Jin-feng HONG Xin-lin ZHANG Gao-yongCollege of Chemistry Molecular Sciences Wuhan University Wuhan Hubei China 《武汉大学学报:自然科学英文版》2005,10(6):1035-1040
0IntroductionApmrpotheiipnhsil ceasn s augchgr eagsa tseurifnatcota an tvsa r,ileitpyid osf , stcroupcotluyrmeser (se a.ngd.micelles ,bilayers ,vesicles and biological membranes ,etc .)inaqueous solutions , which can transformfrom one to anotherwhen the solutionconditions are changed,such as the electro-lyte concentration or the value of pH[1]. The forces that holdamphiphilic molecules together in aggregates are not due tostrong covalent orionic bonds but arisingfromweaker van derWaals ,hydrop… 相似文献
5.
After discussion on the mechanism of polymer particle nucleation and growth in inverse microemulsion polymerization, a schematic physical model for polymerization of acrylamide in inverse microemulsions was presented. Furthermore, several key problems in mathematically modeling of inverse microemulsion polymerization were pointed out. 相似文献
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7.
J. Cao L.C. Yang T. Zhang Y.P. Wu H.Q. Wu 《复旦学报(自然科学版)》2005,44(5):857-858
Lithium-ion batteries have been widely used in portable electronic devices due to their high voltage and high energy density. Most research has concentrated on improving their performance such as capacity, cycling characteristics and low temperature range. Propylene carbonate (PC)-based electrolytes are more desirable than ethylene carbonate (EC)-based electrolytes because of their low-temperature characteristics. Unfortunately, PC is not used in commercial lithium-ion batteries because solvent decomposition and graphite exfoliation occur when lithium intercalates. 相似文献
8.
ZHAO Yaqun WANG Jue 《武汉大学学报:自然科学英文版》2006,11(6):1895-1898
0 IntroductionThe Orthomorphic permutation is one kind of the com-pleteness mapped,andis also the especial Boolean per-mutation. The Boolean permutations have good characteristicsin cryptosystems .It can be consideredthe permutationthat isany cryptosystems lacking outstretched information. For ex-ample,DES(data encryption standard) , which is a standardencryption system,is the permutationin whichthe proclai medin writing controlled by the secret key and RSA( Rivest ,Shamir , Adleman) is a… 相似文献
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10.
《复旦学报(自然科学版)》2007,(5)
1 Results The general principle of the synthesis of fibrous inorganic ion-exchanging composites, containing the combination of polymer analogous conversion reactions of the fibres and cycles of ion-molecular layering is advanced. Synthesis of thin nanomolecular layers of the acid Ti(Ⅳ) and Zr(Ⅳ) phosphates on surface of the cotton fibres and Cu(Ⅱ) and Fe(Ⅲ) ferrocyanides-on polyacrylonitrile fibres was performed on the basis of this principle. By the method of X-ray analysis it was stated that the formed pellicular inorganic layers have a crystalline structure. The synthesis of thin layers of Cu(Ⅱ) and Fe(Ⅲ) hexacyanoferrates (Ⅱ) was performed by the method of the chemosorption layering on a matrix which represented the derivatives of polyacrylonitrile fibres containing HO-N=C·-NH2 groups with the degree of substitution of CN-groups about 50%. According to the data from the X-ray studying of the synthesized pellicular hexacyanoferrates, their composition is described by the formulas KxCu(2-x)[Fe(CN)6]·4H2O and KxFe(4-x)[Fe(CN)6]3 (compounds Ⅰand Ⅱ respectively). By the methods of IR-spectroscopy, formation of heteroatomic cycles by polyacrylonitrile derivatives (with participation of strong H-bonds) was shown. They were capable to disintegrate under the effect ofthe ions of d-metals. It is suggested that strong adhesion of the layers withthe matrix is caused by formation of linkage between [Fe(CN)6]4-ions and the ions in chelates' composition through CN-bridges. The equilibrium ion-exchange capacity on the Rubidium, Cesium and Thallium ions linearly depends on the layer's thickness, which is determined by the number of layering cycles (n) and is equal to 1.0 mmol·g-1 when n=8. Theion-exchange property testing of the synthesized compositions on the basis of the acid Ti(Ⅳ) and Zr(Ⅳ) phosphates was carried out by sorption from water solutions of the strontium and caesium-137 ions, on the basis of the Cu(Ⅱ) and Fe(Ⅲ) ferrocyanides-stable and radioactive caesium isotopes. There is a linear dependency of ion-exchange capacity on the amount of the cycles layering in case the acid Ti(Ⅳ)and Zr(Ⅳ) phosphates is observed. Moreover, the equality of the ionite ion-exchange capacity both on ion strontium, and on ion caesium is observed under fourfold cycle layering. S-figurative nature of such dependence was stated for ferrocyanides. It is shown that the process of the ion exchange proceeding in two stages. The full ion-exchange capacity of ionites on the basis of the acid Ti(Ⅳ) and Zr(Ⅳ) phosphates reaches 2.0 mmol-equ/g, but on the basis Cu(Ⅱ) and Fe(Ⅲ) ferrocyanides-1.0 mmol-equ/g. Ion-exchange equilibrium on synthesized ionites is reachedapproximately 30 times faster, than on corresponding powdery crystalline phosphates and ferrocyanides. Conclusion about prospect of the synthesized material usage in ion-exchange technology, including for extraction of radionuclides is made. 相似文献
11.
CAO Yali LI Guoliang & TANG Zichao State Key Laboratory of Molecular Reaction Dynamics The Center for Molecular Sciences Institute of Chemistry Chinese Academy of Sci- ences Beijing China Correspondence should be addressed to Tang Zichao 《科学通报(英文版)》2005,(9)
Carbon clusters doped with heteroatoms have attracted much attention[1?5], and the special interests come from their role not only in revealing the formation mechanism, but also in guiding the synthesis and application of clus-ters. The collision-induce dissociation experiments and theoretical studies performed on CnP?[3,4], CnN?[6] and CnB?[7,8] have shown that the ground states are the carbon linear structures with P, N and B atom lying at terminal respectively. Except for anions, the neu… 相似文献
12.
Four different suture materials were studied in this study. Pullout friction was conducted to quantitatively evaluate the handling characteristics. The effects of pullout speed, loads and size of suture materials on suture-to-suture friction were proved. Pullout speed and loads affected both static and dynamic friction resistances, and their D-values. The links of three parameters including pullout speed, size of suture materials, and simulative tissue materials to suture-to-tissue friction were studied. Both the suture-to-suture friction and suture-to-tissue friction decreased with the increase of suture diameter. Then a new simulative tissue model was proposed in the suture-to-tissue friction test. 相似文献
13.
Chemical Composition and Antimicrobial Activity of Essential Oil of Asarum caulescene 总被引:2,自引:0,他引:2
Both essential oils of fresh and air-dried Asarum caulescene (Maxim.) were analyzed by GC-MS in three different polarities. The resuits show that thirty-four components were identified in the oils, and main compounds of both oils were β-pinene (7. 63% vs. 20. 77%), 2 carene (8.94% vs. 7.99%), β-phellandrene (7.80% vs. 14.39%), 1,8-cineole (8. 91% vs. 13. 29%) and germacrone (46. 64% vs. 6.64%), however, the content of monoterpene hydrocarhons(30.29% vs. 52. 30%) and oxygenated sesquiterpenes(47.69% vs. 10.65%) of both oils was different. The antimicrobial activity of the oil was evaluated against 3 fungi and 11 hacteria including 7 clinical isolated strains. Our results showed that both oils presented a broad antimicrobial spectrum, and compared with the essential oil from fresh herb, the extracted oil from dried herb had hetter antimicrohial activity, its minimum inhibitory concentration(cmi) values of dried herh were 0. 16-2. 5 g/L and lowest minimum bactericidal concentration(cmb ) value was 0.31 g/L. 相似文献
14.
Formation and evolution of the Chinese marine basins 总被引:1,自引:0,他引:1
JIA ChengZao LI BenLiang ZHANG XingYang LI ChuanXin 《科学通报(英文版)》2007,52(A01):1-11
15.
卢思源 《上海理工大学学报》1983,(1)
Perhaps the readers might wonder why the writer would like to choose the topic "The Teaching and Study of Scientific Prose" for his writing today. The rcason. for this is not far to seek. It is twofold: First, we are teachers of technical English or students majoring in science and 相似文献
16.
ZHUWan-ze LIMai-he ZHANGJun-yan FANJi-hui FANJian-rong 《武汉大学学报:自然科学英文版》2005,10(4):674-681
The floristic elements and the geographical distribution are analyzed in this paper based on statistics of elements of rare and endangered plants in Tibet. The results have been gained as following:① According to ““““the National Important Wild Conservative Plants List (List 1)““““ and ““““the National Important Wild Conservative Plants List (List 1)““““, there are a total of 54 plant species (48 genera and 33 families); ② The geographical elements are very complicated in Tibet with 12 of 15 distribution patterns of genera classified byacademician Wu; ③ There are obvious temperate genera with 28 genera accounting for 60.40% of the total genera; ④ There are abundant endemic speciesaccounting for 18.52% of total species but poor endemic genera; ⑤ The geographical distribution is uneven and a great of species distribute in the areas be-tween 1 000 m and 3 500 m above sea level; ⑥ To protect the rare and endangered plants efficiently, six conservation measures are proposed, and 35 species are suggested for the conservative plants of the autonomous conservation level. 相似文献
17.
A four-point bending apparatus is used to investigate the effects of stretching on collagen synthesis, mineralization and differentiation of osteoblasts. Cells are stretched at 1500με for 24 hours. The responses of osteoblasts to mechanical signal of physiological stretching are evaluatedfrom three aspects: collagen production, extracellular inorganic calcium secretion and ALP activity. The results show that osteoblasts decrease the collagen synthesis, calcium secretion and ALP activity compared to the control cells (65.82 %, 73.51%, 48.10 96 respectively ), confirming that cyclic stretching at 1500με inhabits the ohvsiological activity of osteoblasts. 相似文献
18.
Influence of the Surfactants on Microstructure and the Properties of Wet Coagulation Polyurethane Film. 总被引:2,自引:0,他引:2
IntroductionWhenthehomogeneoussolutionbecomesthermodynamicallyunstable (e g ,bytheintroductionofanonsolvent) ,thesolutionseparatesintotwoliquidphasesofdifferentcompositiontolowerthefreeenergyofthemixture Thisprocessisresponsibleforthegenerationoftheporou… 相似文献
19.
HU Zhong-xiang SHI Xiao-jun SHI Lei 《东华大学学报(英文版)》2005,22(5):34-36
A case of remanufacturing used lathes via CNC technology is introduced, whose environmental and economic benefits are evaluated respectively. The results indicate that these environmental and economic benefits are remarkable, which are directly affected by remanufacturing design, more than 90% materials in used lathes are reused. Finally, the causes of economic and environmental benefits of remanufacturing machine tools are put forward. The remanufacturing design method, implementation procedure, and evaluation method of economic and environmental benefits presented are helpful for other equipment remanufacturing. 相似文献
20.
Formation mechanisms of megadunes and lakes in the Badain Jaran Desert, Inner Mongolia 总被引:5,自引:0,他引:5
CHEN Jiansheng ZHAO Xia SHENG Xuefen DONG Haizhou RAO Wenbo SU Zhiguo 《科学通报(英文版)》2006,51(24):3026-3034
Field observations demonstrate that calc-sinters occurred in the lakes of Badain Jaran Desert. 87Sr/86Sr ratios,14C,δ 13C and mineral com-positions of calc-sinters,and 3He/4He,4He/20Ne,δ 18O,δ D,pH and TDS of water from springs and lakes are analyzed in detail. The results indicate that the lake water is supplied through deep fault zone. The “ker-nel” of stabilized dunes in the Badain Jaran Desert perhaps consists of calc-sinters and calcareous ce-mentation layers. Deep-seated groundwater effuses from this “kernel” and recharges to lakes in desert. Precipitation and snowmelt water from the Qing-hai-Tibet Plateau is fed into the Badain Jaran Desert,Gurinai,Wentougaole and Ejinqi areas through the Xigaze-Langshan Fault zone. The isotopic composi-tions of groundwater in the Alax Plateau are abnor-mal due to the strong evaporation of the Gyaring and Ngoring lake water in the headstream of the Yellow River. Groundwater dissolves dissoluble fractions of rocks during its transportation through the fault zone and flows out of the mouth of spring in the Badan Jaran Desert. The dissoluble fractions are finally de-veloped into calc-sinters and calcareous cementation layers around the spring. Calci-sinters are gradually largened and eventually emerge on the surface of lake water. Eolian sands accumulate on the surfaces of calc-sinters and calcareous cementation layers,and eventually develop into dunes. Invasion of magma causes an increase in the temperature of groundwater within the faults. Groundwater evapora-tion provides water vapor for the formation of humid stabilized dunes during its upwelling. Rhizoconcre-tions found in Yihejigede indicate that the dune was formed and remained immovable 4700 years ago. The height of the megadunes is proportional to thermal quantity carried by the groundwater. 相似文献