脑脓肿的CT诊断

作者报告了１００例脑脓肿，其中一般性脑脓肿６２例、脑内小脓肿３８例（强化灶小于１．５ｃｍ），并对发病部位，临床表现及ＣＴ表现的主要特点进行了讨论。     

螺旋CT扫描高分辨薄层对肺内微小结节诊断的评价

本文通过对２０例小于１ｃｍ的肺内微小结节病灶的分析，比较了螺旋ＣＴ扫描，常规ＣＴ扫描，及胸部平片在临床应用的价值，认为螺旋ＣＴ扫描高分辨薄层重建可以提高肺内微小结节的检出率，并有利于研究结节的内部，边缘和结节的周围情况，从而对早期肺癌的定性诊断和鉴别诊断有重要价值。     

不典型肝脓肿误诊为胆管细胞癌的CT动态增强表现及病理

目的:探讨不典型肝脓肿的CT动态增强表现及其病理基础,提高对肝脓肿及胆管细胞癌的鉴别诊断水平。方法:回顾性分析经手术病理证实的3例不典型肝脓肿的临床资料及CT表现。结果:不典型肝脓肿的CT表现具有多样性,CT平扫病灶呈均匀或不均匀低密度区,形态呈类圆形,边缘模糊或较清楚。增强扫描动脉期病灶呈轻度强化,门静脉期及延迟扫描病灶呈小环状、蜂窝状及不均匀强化,部分形如"花瓣状"改变,类似肝内胆管细胞癌的影像学表现。结论:螺旋CT动态多期增强扫描对鉴别肝内胆管细胞癌与不典型肝脓肿有一定价值。     

肝癌的CT影像特征分析和诊断

本文回顾分析了１１５例肝癌的ＣＴ形像特征,发现肝癌病灶如小于５ｃｍ,因其分化程度较好,ＣＴ图像上多呈现圆形结节影,密度均匀,低或稍低;多数病灶（７５％）边缘光整,部分病灶（２８％）有包膜显示,但随着病灶的增大,病变可突破包膜呈浸润性生长;增强后小肝癌和非小肝癌都可使病灶边缘显示清晰。且病灶较平扫有缩小;肝癌在ＣＴ片上还可以发现的有门脉癌栓和／或肝门、胰周、腹腔淋巴结转移的征象。     

腔隙性脑梗塞的CT诊断及临床特点

本文回顾性分析了１２０例脑腔隙性梗塞的ＣＴ诊断及临床特点,认为梗塞病灶可被清晰、准确的发现。有助于临床的定性分析,为治疗提供了依据。ＣＴ是目前诊断脑腔隙性梗塞的最有效的检查手段。     

利用普及型CT机获得HRCT图像的方法及临床应用

ＨＲＣＴ（高分辨ＣＴ）图像是较常规ＣＴ具有更清晰的空间分辨率的图像。可明显提高图像质量，从而提高病灶细节以及正常和异常细微结构的显示能力，对配合临床诊断及指导临床治疗有着很高的实用价值。如何利用普及型ＣＴ机获得ＨＲＣＴ图像。我们做了技术上的改进，并在不增加硬件设备的基础上利用软件功能，提高一些技术参数，主要是扫描层厚，管电流及扫描时间，高分辨薄层重建，尽可能的缩小显示野，加大矩阵等。所得到的图像分辨率明显高于常规ＣＴ，如肺小结节的显示，腔隙性梗塞的检出率，可疑小腔隙与大的像素颗粒的辨别等。我们认为，进一步开发软件功能。会获得更加理想的ＨＲＣＴ图像     

高分辨率CT(HRCT)扫描在腔隙梗塞中的诊断作用

目的．应用高分辨率ＣＴ（ＨＲＣＴ）扫描方法,增加对头颅腔隙梗塞诊断的可靠性．材料和方法：对临床疑有腔隙的病人在基底节区及可疑部位加用ＨＲＣＴ扫描,遇到腔隙病灶与像素颗粒难以区分时,在相同层面或上下１～２ｍｍ处做ＨＲＣＴ扫描．结果：有２０８例常规ＣＴ正常的病例中发现了腔隙灶,在遇到的３２０例不易诊断的可疑病灶中,经ＨＲＣＴ确诊的真正腔隙灶８９例,伪腔隙（像素）２３１例,同时发现对正常腔组织结构的显示要较常规ＣＴ优越得多,结论：ＨＲＣＴ不仅能提高腔隙梗塞的诊断率,还能辨别伪腔隙是弥补常规ＣＴ对腔隙诊断不足的较好手段。     

利用普极型CT机获得HRCT图像的方法及临床应用

ＨＲＣＴ（高分辨ＣＴ）图像是较常规ＣＴ具有更清晰的空间分辨率的图像。可明显提高图像质量，从而提高病灶细节以及正常和异常细微结构的显示能力，对配合临床诊断及指导临床治疗有着很高的实用价值。如何利用普及型ＣＴ机获得ＨＲＣＴ图像。我们做了技术上的改进，并在不增加设备的基础上利用软件功能，提出一些技术参数，主要是扫描层厚，管电流及扫描时间，高分辨薄层重建，尽可能的缩小显示野，加大矩阵等。所得到的图像分辨率     

青壮年人脑囊虫病CT与临床表现对照研究

本文收集了总结了４０例脑囊虫病的临床资料，并对其ＣＴ表现及病理进行了对照分析，其中脑实型１６例，脑膜型４例，脑室型２例，混合型１８例。作者认为ＣＴ诊断脑事虫病具有很大的特征性：（１）低密度囊状病灶，（２）高密度点状或结节状病灶（３）低密度囊状病灶壁有点状结节状高密度影。ＣＴ检查在显示脑囊虫的数目，位置及分型方面明显优于其它检查。     

单发性脑转移瘤的CT诊断

笔者收集２９例经ＣＴ诊断单发性脑内转移瘤，其中经手术病理证实的２３例，通过对２９个单发病灶的ＣＴ表现进行分析，着重讨论该病灶的出现位置，并对其原因进行了探讨性分析，旨在进一步提高对颅内单发病灶的诊断水平。     

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.     

Earthquake Engineering and Engineering Vibration Aims And Scope

正This journal is established by the Institute of Engineering Mechanics(IEM),China Earthquake Administration,to promote scientific exchange between Chinese and foreign scientists and engineers so as to improve the theory and practice of earthquake hazards mitigation,preparedness,and recovery.To accomplish this purpose,the journal aims to attract a balanced number of papers between Chinese and     

Foreword

Destructive earthquakes have caused great damage in China and the United States and collapsing buildings havecaused many deaths and injuries. The field of earthquake engineering studies earthquake hazards, the occurrence ofearthquakes of various magnitudes, the nature of the ground shaking during an earthquake, the vibration of structuresduring earthquakes, the strengthening of existing structures and the design of new structures to be earthquake resistant,and finally, how to cope with earthquake damage and restore a city to normal functioning. Such efforts are in progressin both countries, but unfortunately, the language barrier interferes with the free flow of information between China andthe Untied States. It would be mutually beneficial if some means could be developed to promote the exchangeof information across the Pacific Ocean. This new journal has been established for this purpose and its success willbe an important step in promoting earthquake engineering in China and the United States.     

WORLD ASSOCIATION FOR SEDIMENTATION AND EROSION RESEARCH(WASER)

正President:Giampaolo Di Silvio,Italy Vice Presidents:Ulrich C.E.Zanke,Germany Zhao-yin Wang,China The World Association for Sedimentation and Erosion Research(WASER),inaugurated on Oct.19,2004,is an independent non-governmental,non-profit organization.The mission of WASER is to promote international co-operation on the study     

Enhancing remote sensing research on global change to improve our understanding on Earth system processes

正Global Change includes climate change and other environmental changes caused by the joint interaction among various layers of Earth. From the positive side, global change provides new opportunities to human and other living forms on Earth. In the meantime, it creates tremendous challenges and negative impact. At present, the negative impacts have reached all primary processes of the global ecosystem and every aspect of human society, especially causing degradation of the ecosystem. For instance, intensive deforestation causes decline of biodiversity; global warming causes sea level rise and increases     

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.