Differential rotation of geomagnetic field

The westward drift of the main geomagnetic field has been extensively studied since Halley[1] first discov-ered this phenomenon. It has been widely accepted that the global field drifts westward with an average velocity of 0.2/a[2—4]. The detailed features of the drift have been also detected, such as different drift rates for dipole and non-dipole fields, drifting and standing parts in the field, the latitudinal dependence of the drift rate, and the north-ward drift[5—12]. Several models, f…     

Latitudinal shift and tilt of the ring current during magnetic storms

The equatorial ring current (ERC) theory suggested that the distribution of global disturbed horizontal geomagnetic field only depends on the cosine of station’s latitude. However, we always observe a larger ΔH at higher latitude stations than lower ones, implying that the ERC could tilt or/and shift with respect to the equatorial plane during intense storms. In this paper, we analyze 11 intense magnetic storms from 2000 to 2004, and introduce two configurational factors to characterize the topology of storm time ring current. The results show that ERC has occasionally deviated off equatorial plane with both tilt angle δ_t≈13°―25° and latitude shift δ_s≈0°―21.8°. The ground disturbed field distribution should be improved as ΔH_k = ΔH_maxcos(φ_k-δ ), which agree well with the geomagnetic observations.     

强中纬力作用下地球板块的运移

以一个块体的理论运动轨迹特殊对象 ,分析在强中纬力作用下 ,地球板块在高纬度带 (6 8°2 7′～ 90°0 0′)、中纬度带 (2 1°33′～ 6 8°2 7′)、低纬度带 (南纬 2 1°33′～北纬 2 1°33′)内等不同地域的受强中纬力作用时的运动方向及其 F- t关系图 ,以及板块在随着地球的自转 ,作跨越赤道的运动情况。结果表明 :地球板块的运动特点随着纬度的变化而变化 ,强中纬力的主要控制因素为地球的黄纬 ;黄纬的变化发生在板块所受强中纬力变化的情况下 ,其外部现象表现为地球纬度的变化。这一结论为由特殊到一般的板块运动分析提供了理论依据     

Cretaceous synfolding remagnetization components revealing tectonic rotation of the middle Yangtze fold belt

To reveal the deformation process of the middle Yangtze fold belt, we conducted a paleomagnetic study on Middle Triassic limestones and Middle to Late Jurassic sandstones from Wanzhou, Chongqing. Stepwise thermal and alternating field demagnetization were used to isolate the multi-component re-manent magnetizations. The Jurassic samples were overprinted by recent geomagnetic field, while three magnetization components were isolated from the Middle Triassic samples. A low temperature component (LTC) was isolated at temperatures below 200℃, an intermediate temperature component (ITC) at 200―360℃ and a high temperature component (HTC) at 400―460℃. The LTC is distributed around the present-day Earth magnetic field, probably a viscous component. Stepwise unfolding indi-cates that the maximum precision parameters of ITC and HTC components are achieved at 33±8% and 50±27% (with 95% confidence) unfolding, respectively. The best-clustered ITC mean direction, Dec = 11.2°, Inc = 45.2° (α₉₅ = 4.5°, N = 34), corresponding to a paleopole at 79.3°N, 219.5°E (d_p = 3.6°, d_m = 5.7°), is consistent with the Cretaceous reference direction of the South China Block (SCB). The best-clustered HTC mean direction (taking 70% unfolding), Dec = 24.2°, Inc =49.0° (α₉₅ = 3.6°, N = 23), corresponding to a paleopole at 69.2°N, 195.5°E (d_p =3.1°, d_m = 4.8°), suggests a clockwise rotation of 12.8°±3.5°. These synfolding remagnetization components clearly reveal that a clockwise rotation happened at the middle stage of folding, thus supporting that at least part of the variation in fold axis strikes is due to orocline rotation. Combined with published data, our analysis indicates that the Wan-zhou-Xiangxi segment of the middle Yangtze fold belt experienced oroclinal bending. Furthermore, a published post-folding component isolated from the Middle Triassic Puqi Formation suggests a 27.5°±5.8° clockwise rotation, confirming that at least 50% of the observed clockwise rotations in the eastern middle Yangtze fold belt can be attributed to oroclinal bending. The remagnetization data and geological evidence observed in the middle Yangtze fold belt suggest that collision between SCB and North China Block (NCB) probably lasted till the early period of Early Cretaceous.     

Antisymmetric transport of middle stratospheric methane with respect to the equator

As one of the important green-house gases, methane in the stratosphere affects the stratospheric processes of radiation, dynamics and chemistry, even the tropo-spheric circulation through interactions between the stratosphere and the troposphere. To a gre…     

Hydrothermal plume anomalies along the Central Indian Ridge

Water column turbidity and temperature were investigated along the Central Indian Ridge （CIR） from 25°19＇S to 23°48＇S during a December 2005 cruise on board Chinese PJV DayangYihao. Measurements were made using NOAA＇s MAPR （Miniature Autonomous Plume Recorder） sensors during CTD casts, TV grabber operations, and tow-yo profiles, yielding the following results on hydrothermal plume anomalies： （1） Strong hydrothermal turbidity and temperature anomalies were recorded over the previously discovered Kairei （25°19.2＇S, 70°02.4＇E） and Edmond （23°52.7＇S, 69°35.8＇E） vent fields, with the plume anomalies concentrated at depths of 2150--2300 m and 2700--2900 m, respectively. The maximum height of the turbidity anomalies near the Kairei vent field recorded in December 2005 was slightly below 2100 m, which is consistent with the plume depth measured in June 2001, indicating that the Kairei plume may have maintained its buoyancy flux in the intervening 4.5 years. （2） The water column beneath the Kairei plume has background anomalies of about 0.005ANTU, whereas no such background turbidity anomalies were observed below the Edmond hydrothermal plume. （3） No visible turbidity anomalies were detected from 24°42＇S to 24°12＇S including the Knorr Seamount. Thus 24°12＇S marks the southern end of the hydrothermal plume. （4） Significant turbidity anomalies were observed at four individual sections from 24°12＇S to 23°56＇S at the depth of 2500--3000 m along the eastern rift valley wall. Whether the individual sections of anomalies are connected is still unknown due to the absence of data at the intervening gaps. If the four sections are connected with each other and are linked to the Edmond vent field farther to the north, the total along-axis length of the plume anomaly would be more than 37 km, implying a plume incidence value Ph of 0.38, greater than the predicted Ph of 0.21 --0.25 based on the spreading rate of the Central Indian Ridge.     

New crystal structure of molecular complex 1-piperidine carboxylate-piperidinium-H<Subscript>2</Subscript>O studied by X-ray single crystal diffraction

Piperidine absorbs CO2 and H2O in air to form a molecular complex： piperidium-l-piperidinecarboxylate-H2O. The structure of the complex was characterized by X-ray single crystal diffraction. The crystal structure was determined to be triclinic, space group P1^-with a=0.648 6（8） nm, b=0.809 200） nm, c= 1.357 1（16） nm, a=96.96706）°, β =102.506（15）°,γ=104.202 05）°, Z=2. The complex is stabilized via five hydrogen bonds between the three components, N-O electrostatic interaction and O-O interaction （electron transfer） betweenl-piperidinecarboxylate and H2O. Due to electron transference of carbamate ion, the oxygen atom in water molecule is strongly negatively charged and the O-H bond is considerably shorter than that of the free molecule of water. The formation of the molecular complex is a reversible process and will decompose upon heating. The mechanism of formation and stabilization is further investigated herein.     

New Early Triassic paleomagnetic data from Huangben section, Guangdong and its tectonic implications

Continent China is composed of several blocks of variable sizes during different geological times, inwhich South China Block is composed of three tectonic units: Yangtze Block, Jiangnan Fold Belt and Southeast China Coastal Fold Belt (Fig. 1(a)), the last…     

Discovery of C<Subscript>4</Subscript> species at high altitude in Qinghai-Tibetan Plateau

Plant specimens are collected from the areas between latitude 27°?2′N and 40°57′N, and longitude 88°93°E and 103°24′E, with an altitudinal range from 2210 to 5050 m above the sea level in Qinghai-Tibetan Plateau. The stable carbon isotope analysis indicates that two of Chenopodiaceae and six of Poaceae in the samples are C4 plants. Four of the C4 plants are found in 11 spots with altitudes above 3800 m, and Pennisetum centrasiaticum, Arundinella yunnanensis and Orinus thoroldii are present in six spots above 4000 m, even up to 4520 m. At low CO2 partial pressure, that sufficient energy of high light improving C4 plant's tolerance of low temperature and precipitations concentrating in growing season probably are favorable for C4 plants growing at high altitude in Qinghai-Tibetan Plateau.     

An experimental study of dehydration melting of phengite-bearing eclogite at 1.5―3.0 GPa

Dehydration melting experiments were performed on ultrahigh-pressure eclogite from Bixiling in the Dabie orogen at 1.5--3.0 GPa and 800--950℃ using piston cylinder apparatus. The results show that （1） eclogite with -5% phengite started to melt at T≤800--850℃ and P = 1.5--2.0 GPa and produced about 3% granitic melt; （2） the products of dehydration melting of phengite-bearing eclogite vary with temperature and pressure. Fluid released from dehydration of phengite and zoisite leads to partial melting of eclogite and formation of plagioclase reaction rim around kyanite at pressures of 1.5--2.0 GPa and temperatures of 800--850℃; （3） phengite reacted with omphacite and quartz and produced oligoclase, kyanite and melt at elevated temperatures. Oligoclase is the primary reaction product produced by partial melting of phengite in the eclogite; and （4） the dehydration melting of phengite-bearing eclogite at pressures of 1.5--3.0 GPa and temperatures ≥900℃ results in formation of garnets with higher molar fraction of pyrope （37.67 wt.%--45.94 wt.%）. Potassium feldspar and jadeite occur at P = 2.4--3.0 GPa and T≥900℃, indicating higher pressure and fluid-absent conditions. Our results constrain the solidus for dehydration melting of phengite-bearing eclogite at pressures of 1.5--3.0 GPa. Combining experi- mental results with field observations of partial melting in natural eclogites, we concluded that phengite-bearing eclogites from the Dabie-Sulu orogen were able to partially molten at P= 1.5--2.0 GPa and T= 800--850℃ during exhumation. The ultrahigh-high pressure eclogites would have experienced partial melting in association with metamorphic phase transformation under different fluid conditions.     

NO<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> reduction by coupling combustion with recycling flue gas in iron ore sintering process

A new process called ‘NO _x reduction by coupling combustion with recycling flue gas (RCCRF)’ was proposed to decrease NO _x emission during the iron ore sintering process. The simulation test of NO _x reduction was performed over sintered ore and in the process of coke combustion. Experimentally, NO _x reduction was also carried out by sintering pot test. For sintered ore, the amount of NO _x emission is reduced by 15wt%–25wt% at 400–550°C using 2.0vol% H₂ or 2.0vol% CO, or reduced by 10wt%–30wt% at 560–720°C using 0.15vol% NH₃. NO _x reduction is around 10wt% by coupling combustion of pyrolysis gas and coke, or around 16wt% by recycling flue gas into coke combustion. By RCCRF, the maximum NO _x reduction ratio is about 23wt% in coke combustion experiment and over 40wt% in sintering pot test.     

Fast and accurate measurement of diffusion coefficient by Taylor’s dispersion analysis

This investigation aimed at improving the performance of Taylor's dispersion analysis for the fast and accurate measurement of diffusion coefficient of a minute solute in various solvents. The investigation was carried out on a capillary electrophoresis instrument by monitoring the UV absorption peak of a solute pulse and calculating the diffusion coefficient by peak efficiency. With L-phenylalanine as a main testing solute, some key factors were afterward disclosed including especially the capillary size, carrier flow velocity, injection volume and capillary conditioning. Peak tailing, large volume of sample injection and slow migration were found to underestimate the diffusion coefficient while very fast migration and high sample concentration caused overestimation. At a moderate flow velocity of 0.1―1 cm/s with a capillary of 72.44 μm I.D.×60 cm (50 cm effective) maintained at 25℃, the diffusion coefficient of aqueous L-phenylalanine was determined, giving a value of 7.02×10-6 cm2/s with error＜2% and relative standard deviation＜0.2% (n=3). The method was shown to be applicable to the measurement of various samples such as aqueous phenylalanine, acetone, phenol, toluene and benzene, and nonaqueous benzene (in ethanol or 1-butanol).     

Optimizing Conditions of Enhancing Granule Sludge Concentration and Performance

An expanded granular sludge bed （EGSB） reactor was adopted to study the influence factors and rule of enhancing granular sludge concentration and performance. The experiment was performed at 33 ℃, pH 6.0-8.0 with continuous flow by adding proper quantity of nutritional trace elements. The results show that SLR was the key of steady operation of EGSB reactor. The increment of the granular sludge was influenced by volume loading rate （VLR）, liquid up-flow velocity and sludge loading rate （SLR）. Concentration of granular sludge increased rapidly when liquid up-flow velocity was over 0.94 m · h^-1 with SLR being at 1.0-2.0 d ^-1. With the propriety parameters： liquid up-flow velocity 2.52 m · h^-1, SLR 1.0-2.2 d^-1 and VLR 8.2-13.1 kg · m ^3 · d^-1, 23 days＇ continuous operation resulted in an increment by over 80% of granular sludge concentration in the EGSB reactor, plus good granular sludge property.     

Dispersion of CoCl2 into γ-Al2O3 studied by positron

Co²⁺/γ-Al₂O₃ samples were prepared by incipient wetness impregnation of γ-Al₂O₃ with different concentration solution of CoCl₂ and dried at 40 °C. We measured the positron lifetime spectra of the samples of different Co²⁺ mass fractions (0%–8.24%) heated at different temperatures (100–500°C). All lifetime spectra were resolved into four components, in which the third and the fourth components were related to the surface state of the micropores and the secondary pores of the γ-Al₂O₃. The experimental results showed that the Co²⁺ was mainly located in the micropores and the secondary pores near to the exterior of the support. For low Co²⁺ mass fraction samples, when the heating temperature was above 400 °C, dispersal was almost finished. When the Co²⁺ mass fraction was above 5.59%, Co²⁺ and Cl⁻ were dispersed into the secondary pores in the form of multiple layers.     

Analysis of carbon isotope in phytoliths from C3 and C4 plants and modern soils

The analysis of carbon isotope in phytoliths from modern plants and surface soils in China shows that the values of carbon isotope are consistent with those from C3 and C4 plants,and the processes of photosynthesis of the original plants can be clearly identified by carbon isotope in phytoliths.The value of carbon isotope varied from -23.8‰ to -28‰,with the maximum distributed in the latitude zone from 34° N to 40° N in North China and East China areas,and the minimum in the Northeast China and South China regions.The values of carbon of phytoliths tend to increase from low to high and then reduce to low value again as the latitude increases.In the same latitude zone,the carbon isotope in phytoliths from grassland soil under the trees is obviously lower than that from grassland soil without any trees with the difference of 1‰-2‰.     

Vp of muscovite-biotite gneiss up to 950℃ at 400 MPa: Constraints on the origin of abnormal seismic layers in continental crust

Here we present experimental results of compressional wave velocity (Vp) of muscovite-biotite gneiss from Higher Himalayan Crystallines (HHC) at the temperature up to 950℃ and the pressure of 0.1―400 MPa. At 400 MPa, when the temperature is lower than 600℃, Vp decreases linearly with increasing temperature at the rate of (Vp/T)p -4.43×10-4 km/s ℃. In the temperature range of 600―800℃, Vp drops significantly and the signal is degraded gradually due to the dehydration of muscovite and α-quartz softening. When the temperature rises from 800℃ to 875℃, Vp increases and the signals become clear again as a result of the temperature going through the β-quartz range. The experiments indicate that the duration has great influence on the experimental results when temperature is above the dehydration point of biotite. During the first 30 h at 950℃, the Vp decreases substantially from 5.9 to 5.4 km/s and the signal amplitude is attenuated by more than 80%. After the 30-h transition, the Vp and the amplitude of ultrasonic wave signals become steady. The decrease of Vp and attenuation of the signals at 950℃ are associated with the breakdown reactions of biotite. The experiments suggest that the breakdown of muscovite and/or quartz softening can contribute to the low seismic wave velocity in thickened quartz-rich felsic-crust such as what is beneath southern Tibet. Additionally, α-β quartz transition generates a measurable high seismic velocity zone, which provides a possibility of precisely constraining the temperature in the upper-middle continental crust. Our study also demonstrates that duration is a key factor to obtain credible experimental results.     

Discovery of a large area of ice-wedge networks in Ordos： Implications for the southern boundary of permafrost in the north of China as well as for the environment in the latest 20 kaBP

Deep sea deposits, ice cores and loess deposits have been used extensively and successfully, to study global climatic changes. Since permafrost is a consequence of cold climates, indicators of permafrost can also be used to reconstruct ancient climates in certain areas during certain periods. The recent discovery of large areas of ice wedge networks, and determination of their ages, have enabled us to locate the southern boundary of the permafrost that ex-isted in China about 20 thousand years…     

A novel method for thermodynamic study on binding of copper ion with Alzheimer’s amyliod β peptide

The interaction of Cu²⁺ with the first 16 residues of the Alzheimer's amyliod β peptide, Aβ (1-16), was studied by employing isothermal titration calorimetry at pH 7.2 and 37℃ in aqueous solution. The Gholamreza Rezaei Behbehani (GRB) solvation model was used to reproduce the enthalpies of Cu²⁺+ Aβ(1-16) interaction over the whole Cu²⁺ concentrations. The binding parameters recovered from the solvation model were attributed to the structural change of Aβ (1-16) due to the metal ion interaction. It was found that there is a set of two identical and non interacting binding sites for Cu²⁺ ions. The molar enthalpy of binding is ΔH=27.895 kJ/mol. The association binding constants are 1.895 μm^-1 and 1.891 μm^-1 for the first and second binding sites respectively.     

New paleomagnetic results from the Yangzhuang Formation of the Jixian System,North China,and tectonic implications

A paleomagnetic study was carried out on the Yangzhuang Formation （-1350 Ma） of the Jixian System in the North China Block （NCB）. Detailed stepwise thermal demagnetization isolated two components. The soft component （component A） was interpreted as a remagnetization in the recent geomagnetic field. The hard component （component B） with higher unblocking-temperatures was carried by hematite. Its site-mean direction is D/I = 77.6°/-24.3°κ= 5.4, α 95 = 18.3°, N = 15 sites） before, and D/I = 72.2°/11.5° （ κ=24.6, α95 = 7.9°） after tilt correction. It passes a fold test（Mesozoic folding） at 99% confidence level and reversal test at 95% confidence level. The corresponding pole locates at 17.3°N, 214.5°E （dp = 4.1°, dm= 8.0°）. A best fit of paleomagnetic poles from the NCB, Baltica, Siberia and the apparent polar wander path for Laurentia suggests a long-lived connection between these paleo-continents between -1800and 1350 Ma.     

Microcalorimetric study on the antibiotic activity of clarithromycin and erythromycin

By using LKB-2277 Bioactivity Monitoring System, the heat effect changes in the process of inhibitory action of clarithromycin and erythromycin onEscherichia coli at 37°C were determined. Quantitative analysis showed that relationship between antibiotic concentrationc and rate contantk ofEscherichia coli growth, and half inhibitory ratio concentration IC₅₀: clarithromycin:k=0. 030 03–1. 1736×10⁻³ c, 8. 45 mg ·L⁻¹; erythromycin:k=0.031 08–8.4657×10⁻⁴ c, 14. 45 mg·L⁻¹. As a result of the microcalorimetry experiments, it not only indicated that antibacterial activity of clarithromycin was stronger than that of erythromycin, but also reported the changeable features of thermodynamics of the bacterial cell in biological, biochemical and metabolic process under different drug action. Foundation item: Supported by Natinal Natural Science Fundation of China (29973030), Natural Science Fundation of Hubei Province (98J052) and Post-doctoral Science Fundation of China Biography, SHEN Xue-song (1956-), Associate professor Research direction: biothermochemistry.