Adsorption characteristics of copper ion on nanoporous silica

Adsorption by nanoporous media is critically involved in many fundamental geological and geochemical processes including chemical weathering,element migration and enrichment,environmental pollution,etc.Yet,the adsorption behavior of metal ions on nanoporous materials has not been systematically investigated.In this study,MCM-41 material with a monodisperse pore size(4.4 nm)and a large BET specific surface area(839 m^2/g)was hydrothermally prepared and used as a model silica adsorbent to study the adsorption characteristics of Cu^2+as a representative metal ion.The Cu^2+adsorption capacity was found to increase with increasing suspension pH in the range from 3 to 5 and to decrease in the presence of NaNO3.At 25℃,pH=5,and a solid-to-liquid ratio of 5 g/L,the adsorption capacity was determined to be 0.29 mg/g,which can be converted to a dimensionless partition coefficient of 45,indicating a strong enriching effect of nanoporous silica.The adsorption isotherm and kinetic data were fitted to several commonly used thermodynamic,kinetic,and diffusion models.The adsorption mechanism was also studied by Fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy and synchrotron-based X-ray absorption spectroscopy.The results suggest that Cu2+ion adsorption is an entropy-driven endothermal process,possibly involving both outer-sphere and inner-sphere complexes.     

近年来我国地震谣言的起因及对策

在充分考虑《中华人民共和国防震减实法》和《地震预报管理条例》中有关地震谣言的新规定的基础上，结合前人的工作，给出了地震谣言的新定义；对1995年12月－1999年1月期间在我国发生的31起地震谣言事件的起因和平息手段进行了研究，并对地震谣言进行了分类；将地震谣言的传播和发展过程分为三个阶段，归纳出了可以采用的地震谣言辟谣工作手段和在辟谣工作中应该注意的问题。     

A Preliminary Interpretation of Near-field Observation Data of the Zhangbei Earthquake

In this paper, a preliminary data processing was made for tbe aftershock records or theZhangbei M6.2 earthquake on Jan. 10, 1998. The hypocenters of 205 earthquakes with M_L≥0.5 were located. The result shows that most aftershockS were concentrated in a more than10 km long and 5～8 km wide NE-trending beIt. The source mechanism solutions of largeraftersbocks were also calculated, from which it can be inferred that the faulted zone of themain shock is an NE-trending fault. Furthermore, the spectral analysis of P waves was made.The corner frequency is about 10 Hz.     

Compensation of time‐delay for control of civil engineering structures

Time‐delay is an important issue in structural control. Applications of unsynchronized control forces due to time‐delay may result in a degradation of the control performance and it may even render the controlled structures to be unstable. In this paper, a state‐of‐the‐art review for available methods of time‐delay compensation is presented. Then, five methods for the compensation of fixed time‐delay are presented and investigated for active control of civil engineering structures. These include the recursive response method, state‐augmented compensation method, controllability based stabilization method, the Smith predictor method and the Pade approximation method, all are applicable to any control algorithm to be used for controlled design. Numerical simulations have been conducted for MDOF building models equipped with an active control system to demonstrate the stability and control performance of these time‐delay compensation methods. Finally, the stability and performance of the phase shift method, that is well‐known in civil engineering applications, have also been critically evaluated through numerical simulations. Copyright © 2000 John Wiley & Sons, Ltd.     

Design of dampers for structures based on optimal control theory

The aim of this paper was to propose a design guideline for using visco‐elastic dampers for the control of building structures subjected to earthquake loading as well as suspension roof structures subjected to wind loading. The active control algorithm was used to calculate the control forces. Based on the single‐mode approach the control forces were transformed to the forces which visco‐elastic dampers can provide. Application of the method to the design of the building structure with passive damping devices in the bracing system and to the suspension roof with dampers was studied. Through the application of optimal control theory a systematic design procedure to implement dampers in structures is proposed. Copyright © 2000 John Wiley & Sons, Ltd.     

颅脑转移瘤的高分辨率CT诊断分析

目的:对颅脑转移瘤的来源、分布部位及瘤周水肿三者关系进行分析与探讨。方法:将54例颅脑转移瘤检出93个病灶,行平扫及增强扫描。将颅脑分为三个区:1区指大脑半球皮髓质交界区;2区指大脑半球;3区指小脑、脑干。水肿分为四个级别:0度无水肿;1度ETR<=1;2度1=2。结果:转移灶1区74个;2区14个,3区5个。水肿程度:0度16个;1度15个;2度26个;3度36个。结论:转移瘤瘤周水肿与转移瘤的来源、恶性程度无关;而与转移瘤的发生部位关系密切.     

痰菌阴性空洞型肺结核的临床CT影像学分析

目的旨在提高肺结核开放－菌阴综合征的诊断和鉴别诊断，材料和方法用回顾性分析经病原学或临床确诊的开放型肺结核，而痰菌阴性的42例病人的CT影像表现。结果得到42例均见斑片状高密度灶影，其中41例不规则空洞影，4例与支气管相通；28例卫星灶影，8例纤维索条影，1例仅见小斑片状影伴卫星灶影，10例见斑点状钙化影，2例淋巴结肿大等。结论是CT对肺结核开放－菌阴综合征的诊断和鉴别诊断有较高的价值，特别是对估价空洞的形态结构，心后区，脊柱旁，后肋隔区，与肺门阴影重叠的病及少量胸腔积液等方面更有价值，对诊断和疗效的观察较可靠。     

测震记录仪时间记录系统常见误差分析

本文讨论我国现阶段,测震台站常用测震仪器的时间记录各环节误差的产生、大小的估计及注意事项。     

中低纬地区地磁脉动的研究

近年来我们对中低纬地区地磁脉动进行了大量的观测和研究。本文不仅介绍了观测仪器的设计、台网设置及数据处理方法。而且还简要地介绍了一些主要科研成果,如低纬Pc3脉动特点,低纬Pi2脉动偏振特性。南极地区的地磁脉动观测结果,以及在磁暴和太阳耀斑期间在低纬地区观测的地磁脉动。这对于进一步认识中低纬地区地磁脉动是十分有益的。     

断层区强余震波传播及影响的动态模拟研究

本文用动态光弹性技术模拟研究了强震发生时,强余震波在断层区内的传播、对江川县城区等关注位置的影响,以及断层对地震波的阻隔作用。结果表明,研究方法实用有效,结果直观,对地震分析具有参考价值。