The Discovery of Natural Native Uranium and Its Significance

This study analyzed the composition and uranium valence of pitchblendes sampled from the hydrothermal Guidong and Zhuguang uranium deposits of the middle Nanling metallogenic belt, Southern China using X-ray photoelectron spectroscopy (XPS). A revolutionary discovery is that the uranium not only exists in the forms of tetravalent and hexavalent uranium oxides, but also occurs in the form of native uranium. This is the first discovery of the existence of native uranium in nature. It greatly helps to reveal the origin of hydrothermal mineralization of uranium, and also has great significance for studying the thermal energy, formation and evolution of the earth.     

山西王家岭煤矿采空区钻探验证分析

以王家岭煤矿首采区物探解释的CK2、CK6采空区为例,分析了采空区物探特征,根据煤矿区地质、水文地质特征,结合小煤窑的分布及开采特征,利用钻探手段对采空区进行了验证。在验证时,主要考虑了钻探、煤层厚度、简易水文、区域含水层水位、裂隙含水层富水性5个方面的影响因素。结果表明,物探解释的采空区是可靠的,并且查明了采空区的起止深度及其积水情况。对煤矿的巷道布设、井下探放水的实施和安全开采具有一定的指导意义。     

岩浆岩的熔点、粘度及其与化学成分的关系

本文研究了我国中、新生代一些岩浆岩的化学成分、熔点、人工玻璃的折射率和比重以及它们在不同温度下的粘度。在常压下岩石酸度愈大,熔点愈高。熔点与岩石的Fe~(2+(+Fe~(3+)+Mn+Mg±Ca为反相关;与Si+Al+K+Na为正相关。计算粘度与温度的关系表明,酸度愈大,粘度愈大;碱度愈大,粘度愈小,温度愈高,粘度愈低;同一温差下,酸度愈大,粘度变化愈大。     

Phase relations in the system NaCl-KCl-H2O II: Differential thermal analysis of the halite liquidus in the NaCl-H2O binary above 450°c

Thermal analysis of the halite liquidus in the system NaCl-H₂O has been conducted for NaCl mole fractions (X_NaCl) greater than 0.25 (i.e., > 50 wt. % NaCl) at pressures between 0.3 and 4.1 kb and temperatures greater than 450°C. The position of the liquidus was located by differential thermal analysis (DTA) of cooling scans only, as heating scans did not produce definitive DTA peaks. The dP/dT slope of the liquidus is positive and steep at high pressures, but at high X_NaCl, and pressures below 0.5 kb it appears to reverse slope and intersects the three-phase curve (liquid-halite-vapour) at a shallow angle. However, due to the complex nature of the DTA signal when P <- 0.5 kb, there is considerable doubt about exactly what event has been recorded in the experiments conducted at these low pressures.The solubility of halite can be expressed as a function of the mole-fractional-based activity of NaCl in the liquid phase (L) in temperature (T, °K) and pressure (P, bars) In $\text{α}{}_{\mathrm{NaCl(L.T.P)}}\text{=}\text{?19.884 ? 0.001275T ? 1388}\text{T + 3.2305 In (T) ? 0.07574PT}$ Our liquidus data (based on 10 compositions) above 500 bars for these brines were combined with this equation to generate activity coefficients of NaCl which were fit within their experimental uncertainties to the following one parameter Margules equation In $\text{γ}{}_{\mathrm{NaCl(L.T.P)}}\text{=}\text{(0.7268 ? 695.7}\text{T ? 0.1217PT)}\text{(1 ? X}{}_{\mathrm{NaCl}}\text{)}{}^2$. Concentrated solutions of NaCl show negative deviations from ideality which rapidly increase in magnitude with decreasing X_NaCl.     

Silica Mass-Balance and Retention in the Riverine and Estuarine Scheldt Tidal System (Belgium/The Netherlands)

An annual budget for dissolved silica (DSi) and biogenic silica (BSi) was constructed for the Scheldt estuary and for the entire riverine and estuarine Scheldt tidal system (Belgium/The Netherlands) using previously published silica concentrations and fluxes for the period 2003–2005. The annual estuarine DSi mass-balance was established, based on seasonal fluxes estimated using measured DSi concentrations and (fully transient) model simulations of conservative transport. The annual BSi mass-balance was deduced from measured BSi contents in the suspended particulate matter and annual mud fluxes taken from the literature. The Scheldt estuary acted as a net sink not only for the BSi carried by the tidal river as well as that produced by diatoms in the estuary, but also for large amounts of BSi imported from the coastal zone. This results in the retention of dissolved and biogenic silica higher than that of DSi alone, which is in contrast with the classical consideration that rivers act as a source of BSi for the coastal zone. DSi and silica (DSi + BSi) retentions amounted to, respectively, 28 and 64 % in the estuary, and 33 and 66 % in the entire tidal system. This study highlights thus the predominant role of the estuary in the entire Scheldt tidal system when dealing with silica dynamics, as well as the importance of including BSi when investigating estuarine silica retention.     

Extracting predictable components and forecasting techniques in extended-range numerical weather prediction

This paper refers to the CNOP-related algorithms and formulates the practical method and forecast techniques of extracting predictable components in a numerical model for predictable components on extended-range scales.Model variables are divided into predictable components and unpredictable chaotic components from the angle of model prediction error growth.The predictable components are defined as those with a slow error growth at a given range.A targeted numerical model for predictable components is established based on the operational dynamical extended-range forecast(DERF)model of the National Climate Center.At the same time,useful information in historical data are combined to find the fields for predictable components in the numerical model that are similar to those for the predictable components in historical data,reducing the variable dimensions in a similar judgment process and further correcting prediction errors of predictable components.Historical data is used to obtain the expected value and variance of the chaotic components through the ensemble forecast method.The numerical experiment results show that this method can effectively improve the forecast skill of the atmospheric circulation field in the 10–30 days extended-range numerical model and has good prospects for operational applications.     

The Effect of Helicity Dissipation on the Critical State of an Avalanche Model for Solar Flares

We perform numerical simulations using an avalanche model for solar flares, in which the effect of avalanche event duration is included and the lateral boundary condition can be either open or periodic. The results from the simulations show that self-organized criticality (SOC) exists under a variety of conditions of helicity dissipation, and they are similar in the sense that the indices of power-law distributions of avalanche sizes are the same, while the duration and waiting time distributions differ little. Of interest are: (1) if there exists helicity dissipation in the course of avalanches, SOC exists only when the amount of helicity dissipation per avalanche is small; (2) sudden reductions in the total helicity of the system do not severely disturb SOC, if the amount reduced is moderate; (3) the distribution of waiting times is shown to be exponential, in consistent with the Poisson statistics other avalanche models have predicted, and the exponent increases as the effect of event duration becomes larger. The self-similar structure of the avalanche time series is also examined. These results imply that, although helicity is dissipated in resistive diffusion of flares, the amount of dissipation should be small and the conservation law of helicity thus holds in an approximate sense. Also, the coronal mass ejections (CMEs), observed to take helicity out of the solar corona in an eruptive way, may disrupt the statistical equilibrium of the corona only temporarily.     

圆尾斗鱼的胚胎和仔鱼发育的研究

圆尾斗鱼的受精卵呈圆球形，光滑，略带淡黄色，浮性；卵膜吸水膨胀后的平均直径为１．１９ｍｍ，当水温２１－２３．５℃时，从受精卵到孵化出膜需４２．５小时；水温２２－２４．５℃时，刚出膜仔鱼到卵黄囊消失需４天，到油球消失约２５天。出膜３０天仔鱼的形态基本与成体相似。     

The comparison of PCA and discrete rough set for feature extraction of remote sensing image classification – A case study on rice classification, Taiwan

Texture information offers an extensive solution for image classification by providing better accuracy of image information. However, huge amounts of improper additional texture information may result in a chaotic state, and this leads to uncertainty in the classification process. Considerable portion of earlier works have been carried out through the generally acknowledged procedure of Principal Components Analysis (PCA). However, the PCA method has flaws in the area of influenced and non- influenced attributes. On the whole, whether PCA provides an effective solution to determine the value of knowledge rule in image information still remains a question. This study proposes an innovative method, called Discrete Rough Set method, as a tool for image classification. This study focuses on two crucial issues: (1) The core attributes of the target categories in image classification are systematically analyzed while eliminating surplus attributes rationally; (2) The unique point of each attribute, which influenced the target categories, is successfully found. This is a crucial aspect that is very helpful for the construction of decision rule. Finally, in this study we utilized the expert knowledge classifier and the overall accuracy of Discrete Rough Set (96.67%) exceeds that of the conventional PCA (86.00%) of paddy rice area evaluation from Quickbird image. This result shows that the appropriate classification knowledge can be presented by Discrete Rough Set, and this information can effectively improve the accuracy of image classification. An erratum to this article can be found at