K~+-FREE INDUCED EARLY AFTERDEPOL-ARIZATION IN CARDIAC VENTRICULAR FIBERS OF GUINEA PIG AFTER COLD TREATMENT

The genesis and elimination of early afterdepolarizations (EADs) have been investigated in guinea pig cardiac ventricular fibers after a short period of cooling (5h, 2—4℃). After rewarming them to 37℃, EADs could be induced by K~+-free superfusion at an appropriate driving stimulation (0.2 Hz) in all preparations. A high level plateau, which linearly increases its duration with time, appears ahead of EADs. The critical point of the plateau occurred steadily at the level of -47±4 mV. Two types of triggered activity, all of which are the rhythmic activities in low level of membrane potential (-50 to -60 mV), appear on the platcau. There is no significant change after overdriving. Agonists of the Na-K pump (K~+ and Tl~+) could stop the rhythmic activity immediately and turn the low level of membrane potential to high one. The results showed that high level plateau is the basis of genesis of EADs, and the activation of Na-K pump plays an important part in stopping triggered rhythms arising from EADs.     

Quantitative surface analysis by Auger and x-ray photoelectron spectroscopy

Recent developments in quantitative surface analysis by Auger (AES) and x-ray photoelectron (XPS) spectroscopies are reviewed and problems relating to a more accurate quantitative interpretation of AES/XPS experimental data are discussed. Special attention is paid to consideration of elementary physical processes involved and influence of multiple scattering effects on signal line intensities. In particular, the major features of core-shell ionization by electron impact, Auger transitions and photoionization are considered qualitatively and rigorous approaches used to calculate the respective transition probabilities are analysed. It is shown that, in amorphous and polycrystalline targets, incoherent scattering of primary and signal Auger and photoelectrons can be described by solving analytically a kinetic equation with appropriate boundary conditions. The analytical results for the angular and energy distribution, the mean escape depth, and the escape probability as a function of depth of origin of signal electrons as well as that for the backscattering factor in AES are in good agreement with the corresponding Mote Carlo simulation data. Methods for inelastic background subtraction, surface composition determination and depth-profile reconstructions by angle-resolved AES/XPS are discussed. Examples of novel techniques based on x-ray induced photoemission are considered.     

Reaction of early transition metal complexes with macrocycles. II. Synthesis and structure of TiCl3(H2O) · 18-crown-6, a compound with a unique bidentate bonding mode for the 18-crown-6 molecule

18-crown-6 reacts with TiCl₃ in CH₂Cl₂ to form a complex in which the crown ether functions as a tridentate ligand. Addition of moist hexane affords a molecular complex in which the crown ether functions as a bidentate ligand. A water molecule is bonded directly to the titanium atom and is further hydrogen bonded to three of the oxygen atoms of the crown. The deep blue crystals of the CH₂Cl₂ adduct belong to the monoclinic space groupP2₁/n witha=13.481(8),b=8.021(5),c=21.425(9) Å, =97.32(5)°, and _calc = 1.51 g cm^–3 forZ=4. Refinement led to a conventionalR value of 0.040 based on 873 observed reflections. The Ti–O bond distances for the crown oxygen atoms are 2.123(8) and 2.154(9) Å, while the oxygen atom of the water molecule is bonded at 2.072(8) Å. The octahedral coordination sphere of the titanium atom is completed by the three chlorine atoms at distances of 2.340(5), 2.352(4), and 2.373(4) Å. Supplementary Data relating to this article are deposited with the British Library as Supplementary Publication No. SUP 82034 (10 pages).     

A thermodynamic analysis on the coincidence of extrema conditions in the sorption equilibrium for ternary polymer systems

Flory-Huggins theory of polymer solutions has been used to express the condition of extrema values in the total sorption, as well as the inversion point in the preferential adsorption parameters for termary polymer systems. Two approaches have been followed, the first considers the binary and ternary interaction parameters independent of polymer concentration and solvent composition. In the second one, this dependence has been introduced. Our attention is focused on the volume fraction of solvent mixture dependence of the above parameters, in order to confirm or not the coincidence between the extrema values and the inversion point. Several cosolvent and cononsolvent ternary polymer systems, have been used to test the validity of the equations obtained. Also, it has been verified, from an experimental point of view, that in cosolvent ternary polymer systems there is coincidence in both compositions while in cononsolvent ternary polymer systems, such coincidence does not appear.     

Pyrite Genesis During Early Diagenesis in Yellow Sea and East China Sea

The content and isotopic compositions of different sulphur species in pore-water and solid phases have been examined on five sediment cores taken from muddy sediment region in the Yellow Sea and the East China Sea. Relationships among these data have been investigated with the combination of morphology of mineral pyrite and organic matter so as to role out the diagenetic behaviour of sulphur species at the early stage of diagenesis in modern marine sediment and the origin of pyrite formation.     

Topotactic reversible phase transition between room-temperature and a new low-temperature modification in the MCl3(THF)3 system

Both single crystals of VCl₃(THF)₃ as well as isotypic cocrystals of the composition MCl₃(THF)₃, M=Ti/V 1/3, undergo a topotactic reversible phase transition to a hitherto unknown low-temperature modification. The close relationship between this new structure and the room-temperature phase determined by Cottonet al. is discussed from the molecular and the intermolecular point of view: Both modifications are built up by conformationally very similar molecules which change their arrangement during the phase transition. Lattice energy calculations confirm that these two alternative arrangements correspond to minima of almost the same packing energy.Dedicated to Professor Dr. G. E. Herberich on the occasion of his 60th birthday.     

HEAT TRANSFER AND PRESSURE DROP FROM LOUVERED SURFACES IN AUTOMOTIVE HEAT EXCHANGERS

An investigation of heat transfer and pressure drop from some louvered surfaces is presented. The test rig and the measuring as well as the data evaluating procedures are described. The measured data are transferred and presented in a nondimenswnal form. The heal transfer data are provided mainly as Stanton numbers versus Reynolds number, and the pressure drop is given as Darcy friction factors versus Reynolds number. For comparing the performance of the various louvered surfaces, the flow area goodness factors and the so-called volume goodness factors are presented. All the louvered surfaces have been found to be more efficient than the corresponding smooth surface. The standard multilouvered fin surfaces were found to be most efficient, but one of the new surfaces also performed very well.     

Estimation of the total population moving into and out of the 20 km evacuation zone during the Fukushima NPP accident as calculated using “Auto-GPS” mobile phone data

The first objective data showing the geographical locations of people in Fukushima after the Fukushima Dai-ichi nuclear power plant accident, obtained by an analysis of GPS (Global Positioning System)-enabled mobile phone logs, are presented. The method of estimation is explained, and the flow of people into and out of the 20 km evacuation zone during the accident is visualized.     

Generalized matching theorems for closed coverings of convex sets

In this paper we use fixed point and coincidence theorems due to Park [8] to give matching theorems concerning closed coverings of nonempty convex sets in a real topological vector space. Our new results extend previously given ones due to Ky Fan [2], [3], Shih [10], Shih and Tan [11], and Park [7].     

地下水脆弱性风险预警和评估的区间三角模糊多属性决策模型

应用基于逼近理想解排序法的区间三角模糊多属性决策模型,对三江平原六大分区地下水脆弱性进行了风险预警和评估.评估结果与前人吻合,可为有关决策部门采取相应降低环境风险的措施提供参考.实例验证表明,模型具有更高的计算精度和更好的评价效果,为有关环境风险决策部门对地下水风险预警和评估提供了新的思路和方法.