《CT理论与应用研究》杂志在国际互联网上查看和交流的办法

本刊《ＣＴ理论与应用研究》杂志从２０００－２月起，即开始在北京民营科技网上，开辟了“ＣＴ科技进展与科技咨询的网页／ｗｗｗ．Ｍｙｓｔａｒ．ｃｏｍ．ｃｎ／３ＤＣＴ／”登载千禧之年“第七届 １９９９年度亚洲 ＣＴ科技十大进展与中国ＣＴ科技新进展信息交流会”的有关信息和评述．从２０００－０５月起，陆续登载“首届２０００年国际ＣＴ和三维成像会议”的组委会和征文及发奖事项。 本刊从１９９４年起，即向清华大学“国家学学术期刊光盘中心”和“ＣＮＫＩ中国期刊网”提供每期的杂志和相应的文章软磁盘，从２００ｉＮ１０日起…     

江苏-南黄海地区未来地震形势的统计分析

根据１５００年以来的地震资料,应用数理统计、灰色预测、干支６０周期分析等多种方法,对江苏—南黄海地区未来３～５年地震形势进行分析和预测,结果表明：该区目前处于本世纪第２活跃幕中后期,未来几年内依然存在５～６级地震的危险性,至２０００年７月,累积发震概率将达到０．７～０．８,１９９９—２０００年、２００２—２００３年均有可能发生５级以上中强地震。     

岫岩—海城5.1级地震宏观考察及震灾损失评估

继海震５．６级地震以后,于２０００年元月１２日灾海城、岫岩交界处发生了５．１级地震,震中烈度为ＶＩＩ度。本文就这次地震的特点和震灾损失作了阐述,这次地震所造成的损失为２６５１．８４万元。     

用门限自回归建模对山西地区地震活动进行预测

利用门限自回归原理对山西地区未来地震活动进行了预测。结果表明，山西地区至２０００年可能发生的最大地震的震级为ＭＬ５．３，而１９９７年可能发生的最大地震震级为ＭＬ４．１。认为，在该区未来几年内发生ＭＳ≥６．０地震的可能性不大。     

日食一厄尔尼诺系数及其应用

通过比较本世纪以来的厄尔尼诺年和日食资料,发现了高纬（包括极区）日食与厄尔尼诺年之间存在着一定的因果关系。通过定义年日食一厄尔厄诺系数Ｒ１和累积日食一厄尔尼诺系数Ｒ２后,可以发现当某年的Ｒ１≥９或Ｒ２≥１０．５级时,则当年必为厄尔尼诺年,反之亦然．本文还提出了日食诱发厄尔尼诺现象的热一动力机制,并预测２０００年将是一个强厄尔尼诺年．     

山西地区未来3年地震强度预测

选取１９７０年至１９９７年时间段内发生在山西地区的逐年最大震级,采用门限自回归原理进行建模,经过反复对比,选取最佳模型,预测得知该区未来３年（至２０００年）发生强震（Ｍｓ＞６．０）的可能性不大。     

利用门限自回归建模预测广东地区2000年前后的地震强度

利用自激励门限自回归建模的原理和方法,对广东地区陆地和珠江口外以及台湾海峡部分地区２０００年前后的最大地震强度进行了预测。结果表明,该区至２００１年可能发生地震的最大震级为ＭＬ５．２级,未来几年内发生Ｍ≥６．０级地震的可能性较小。     

内蒙古湖相沉积14C年代测定中“硬水”影响的发现

对内蒙古科尔沁沙地巴克窑泡子湖相沉积物分别做了＾２１０Ｐｂ和＾１４Ｃ测年,比较这两种方法测定结果发现,＾１４Ｃ年龄比＾２１０Ｐｂ估计年龄偏老约２０００年,内蒙古其它湖泊的沉积物＾１４Ｃ测年资料一般也都存在年龄偏老问题,作者认为,这一现象主要是由干燥和半干燥地区湖泊“硬水”影响引起的。     

纪念著名地球物理学家、教育家傅承义院士

２０００年１月８日,国际著名地球物 理学家、我国地球物理事业的主要奠基 人和先驱者傅承义院士永远离开了我 们,他为地球物理科学和教育事业做出 的卓越贡献,我们永远怀念． 傅承义先生原籍福建闽侯, １９０９年 １０月７日生于北京．他自幼天资聪颖、 勤奋好学． １９２９年以理化、数学两项银 杯奖的优异成绩从北京汇文高级中学 毕业．１９３３年毕业于清华大学物理 系,留校做研究生,从事核物理实验和 研究工作的同时,还从事教学工作． １９３７年抗日战争爆发后,清华大学、北 京大学和南开大学在昆明成立西南联 大．１９３８年…     

1998年2月4日阿富汗地震概况

１９９８年２月４日阿富汗北部地区发生里氏６．１级破坏性地震,造成重大人员伤亡和财产损失,至少２０几个村庄被毁,４４５０人死亡,２０００多人受伤,数万人无家可归。本文综合介绍了这次地震的破坏和人员伤亡,地震参数,发震背景,地质构造的历史地震记录及抗震救灾情况等。     

A Monte Carlo study of rainfall forecasting with a stochastic model

A procedure for short-term rainfall forecasting in real-time is developed and a study of the role of sampling on forecast ability is conducted. Ground level rainfall fields are forecasted using a stochastic space-time rainfall model in state-space form. Updating of the rainfall field in real-time is accomplished using a distributed parameter Kalman filter to optimally combine measurement information and forecast model estimates. The influence of sampling density on forecast accuracy is evaluated using a series of a simulated rainfall events generated with the same stochastic rainfall model. Sampling was conducted at five different network spatial densities. The results quantify the influence of sampling network density on real-time rainfall field forecasting. Statistical analyses of the rainfall field residuals illustrate improvement in one hour lead time forecasts at higher measurement densities.     

Dynamische Modellierung des pH-Einflusses bei der Nitrifikation hochbelasteter Abwässer Dynamic Modelling of the pH Influence in Nitrification of Highly Concentrated Wastewater

Wastewater with high ammonia concentrations is produced by many industries, e.g. in the production of fertilizer and explosives and in the agricultural and food industry. A direct discharge into rivers and lakes has to be avoided: Oxidation of ammonia requires 4.56 g DO/g NH⁺₄-N and results in a decrease of dissolved oxygen concentration. Moreover, nitrate stimulates the proliferation of algae, with regard to the eutrophication of natural waters. For municipal wastewater with an ammonia concentration less than 50 mg/L NH⁺₄-N nitrification is a standard process. However, the removal of higher loaded industrial effluents still poses many questions. Recently, lab-scale and pilot-scale investigations show remarkable advances in the increase in nitrification efficiency and in the stabilization of the process. But because of changing flowrates and concentrations, the aid of advanced control algorithms is necessary. Some of the most important variables of biochemical reactors can be determined only with difficulty, at times only with off-line measurements. Model-aided measurement approaches try to determine these variables indirectly from easily measured variables. An experimentally-proved reactor model is required. Therefore, a dynamic model of nitrification in ideally mixed reactors is proposed based on mass balances for the components ammonia. nitrite, nitrate. dissolved oxygen DO, carbon dioxide, pH. nitrosomonas and nitrobacter. The biological reaction rates consider oxygen limitation and substrate inhibition. The process model presented is tested by lab scale experiments using an aerated stirred tank reactor and a fluidized bed reactor. Conformity between the predictions of the model and the observed data was positive. It has been shown that the nitrite oxidation by nitrobacter is the most sensible step in nitrification.     

Depositional ages and characteristics of Middle–Upper Jurassic and Lower Cretaceous lacustrine deposits in southeastern Mongolia

Lower Cretaceous lacustrine oil shales are widely distributed in southeastern Mongolia. Due to the high organic carbon content of oil shale, many geochemical studies and petroleum exploration have been conducted. Although most of the oil shales are considered to be Early Cretaceous in age, a recent study reveals that some were deposited in the Middle Jurassic. The present study aims at establishing depositional ages and characteristics of the Jurassic and Cretaceous lacustrine deposits in Mongolia. The Lower Cretaceous Shinekhudag Formation is about 250 m thick and composed of alternating beds of shale and dolomite. The Middle Jurassic Eedemt Formation is about 150 m thick and composed of alternating beds of shale, dolomitic marl, and siltstone. The alternations of shale and dolomite in both formations were formed by lake level changes, reflecting precipitation changes. Shales were deposited in the center of a deep lake during highstand, while dolomites were formed by primary precipitation during lowstand. Based on the radiometric age dating, the Shinekhudag Formation was deposited between 123.8 ±2.0 Ma and 118.5 ±0.9 Ma of the early Aptian. The Eedemt Formation was deposited at around 165–158 Ma of Callovian–Oxfordian. The calculated sedimentation rate of the Shinekhudag Formation is between 4.7 ±2.6 cm/ky and 10.0 ±7.6 cm/ky. Shales in the Shinekhudag Formation show micrometer‐scale lamination, consisting of algal organic matter and detrital clay mineral couplets. Given the average thickness of micro‐laminae and calculated sedimentation rate, the micro‐lamination is most likely of varve origin. Both Middle–Upper Jurassic and Lower Cretaceous lacustrine oil shales were deposited in intracontinental basins in the paleo‐Asian continent. Tectonic processes and basin evolution basically controlled the deposition of these oil shales. In addition, enhanced precipitation under humid climate during the early Aptian and the Callovian–Oxfordian was another key factor inducing the widespread oil shale deposition in Mongolia.     

Solute concentrations in the lower niger river and the source rock contribution

Water quality analyses for the Niger River for the 1980/81 hydrological year are presented. The samples were collected from the main river at Lokoja, and from two main tributaries, the Kaduna and the Benue Rivers. Different water types were distinguished by the concentrations of major ions. The type Ca > Na > Mg > K - HCO₃ > SO₄ > Cl was represented at all stations during at least part of the year. Chloride was found to dominate the sulphate ion in the Kaduna and Niger, while the Benue maintained a higher concentration of sulphate relative to chloride all year round. Distinct patterns of seasonal variation in the ion concentrations were observed, particularly for the samples collected at Lokoja. Low ion concentrations were prominent during periods of high discharge, while low flow periods coincided with high dissolved ion concentrations. The contribution of rainwater to the total dissolved solids in the river waters was assessed indirectly using rainwater chemistry data from the Gulf of Guinea. The estimated rainwater contribution to the Lower Niger amounts to 5.15 mg 1^?1. Geochemical weathering calculations involving reactions of the four major minerals of granitic rocks - anorthite, biotite, albite, and K-feldspar - with carbon dioxide and water, can account for the average water composition of the Lower Niger. The proportion of the ionic components was also related to the occurrence of the respective element in the minerals.     

A numerical and experimental study of hollow steel pile in layered soil subjected to lateral dynamic loading

The present study aims at investigating the nonlinear behavior of single hollow pile in layered soil subjected to varying levels of horizontal dynamic load. A finite element model has been developed using commercially available FEM based software. Mohr–Coulomb plasticity model is used to simulate the soil plasticity whereas the pile-material is idealized as elastic. Numerical results are validated comparing with the experimental results. The experimental investigations were carried out in the field located at IIT Kharagpur. Two types of motion: horizontal and rocking are studied. The effects of various influencing parameters, namely, exciting moment, length and diameter of the pile etc. on the nonlinear dynamic response of piles are investigated. It is found that separation of pile from the surrounding soil considerably affects the resonance frequency and amplitude of the pile foundations.     

Modelling the Kinetics of Calcium Hydroxide Dissolution in Water

In water treatment calcium hydroxide is used in softening and decarbonization techniques as well as in stabilization processes. Due to its slight solubility calcium hydroxide is applied as suspension. The dissolution kinetics plays a major role in these processes. For the characterization of calcium hydroxide dissolution empirical methods exist. These methods allow relative comparison of different calcium hydroxide products. Thus in this study a dissolution rate model is presented that is based on the chemical reactions determining the dissolution. This model allows to predict the dissolution with respect to particle diameter and temperature. However, the most important factor is the particle diameter i.e. the total surface of particles in solution. Furthermore an effect of the dosed amount of calcium hydroxide particles on the solubility was found.     

Prevalence and abundance of two trematode parasites,Diplostomum phoxini andMacrolecithus papilliger in European minnows (Phoxinus phoxinus) in an artificial Swiss Alpine lake

The influence of parasites on the breeding biology of the European minnow (Phoxinus phoxinus) was studied by examining 268 adult and 59 young-of-the-year minnows from an artificial Swiss Alpine lake for parasites during the breeding seasons in 1990 and 1991. Two trematode parasites;Diplostomum phoxini, in their brains, andMacrolecithus papilliger, in their guts, were found. The prevalence ofD. phoxini was 100% in both years. The mean abundance was 231 in 1990 and 448 in 1991; the difference was significant. Prevalence (and abundance) ofM. papilliger was 37.5% (1.04±0.39) in 1990 and 59.5% (2.68±0.55) in 1991; also significantly higher in 1991 than in 1990. No differences in prevalence or abundance between males and females were found. Numbers of both parasites were significantly correlated with fish length. There was seasonal variation in the abundance ofD. phoxini metacercariae, with a peak in June/July in both years. The prevalence ofM. papiller decreased after July in both years. Distribution of the two trematodes was overdispersed as indicated by the variance to mean (abundance) ratio. The observed seasonal variation inD. phoxini abundance also suggests that sublethal parasites could influence the population dynamics of their hosts.     

Approaches to the Immunochemical Analysis of Non-extractable Triazine Residues in Refractory Organic Substances (ROS) and Characterization of ROS

The tendency of several pesticides to form non-extractable residues requires simple and fast screening methods. Immunochemical methods can meet this demand. They are based on selective and highly sensitive antibody binding to pesticide residues exposed on refractory organic substances (ROS). s-Triazines were used as an example to show the feasibility of this approach. It was proven that under laboratory conditions atrazine was bound to ROS. Antibody recognition pointed to the availability of free ethyl and isopropyl groups exposed at the non-extractable s-triazine residue. Therefore, it is suggested on the basis of antibody selectivities that binding of atrazine to ROS may take place by substitution of the chlorine residue. In the next step, aquatic ROS isolated from surface waters located in an agricultural area were examined for non-extractable s-triazines. ROS from a lake were found to contain bound residues, whereas none were detected in the creek samples. As an outlook the feasibility of serological characterization of ROS is discussed. The novel concept of serotyping is based on the fractionation of ROS by electrophoretic techniques followed by an immunoreaction with polyclonal antibodies directed against different ROS. When immunoelectrophoresis is used, precipitation lines can be compared and checked for identity and cross-reactivity. This approach can form the basis for classifying ROS and determine similarities with unknown ROS.     

Präzipitation von Aluminium und Phosphat in Gewässern unter dem Einfluss von Versauerung

Precipitation of Aluminium and Phosphate Affected by Acidification Acidified waters often show elevated concentrations of Al (with up to 6 mg L^–1 being not unusual). A pH increase resulting e.g. from mixing with non‐acidified water or from biological activities may be linked with Al precipitation. Up to now, this phenomenon was described for acid mine drainages. This investigation focuses on a whitish precipitate naturally formed in a brook of an atmospherically acidified catchment in the Ore Mountains, Germany. Based on infrared spectra the precipitate was identified as an Al‐hydroxosulfate with crystal water. A simulation of natural conditions in the laboratory showed that Al precipitated only if sulfate or phosphate ions were added to the solution. In the case of sulfate being added, the infrared spectrum of the precipitate was similar to the natural precipitate. ²⁷Al NMR spectroscopy revealed tetrahedrally coordinated Al in some precipitates which evidences the participation of the tridecameric [Al₁₃O₄(OH)₂₄(H₂O)₁₂]⁷⁺ cation beside other polymeric Al cations. Precipitation experiments subjected to the given conditions showed that the phosphate elimination from solution with Al was much higher than with Fe. With Al and Fe added together, the P elimination rate was likewise high, and phosphate was bound onto Al in the precipitate. This was demonstrated by SEM‐EDX spectroscopy. Based on these results we present a possible reaction mechanism. The precipitation of Al together with P allows a significant retention of both elements in sediments because in contrast to Fe, Al immobilizes phosphate even under anoxic conditions.