X线及CT检查在外伤性骨质疏松中的应用及讨论

目的 讨论CT及X线检查在外伤性骨质疏松中的应用。方法 1998－2000年200例外伤复查病人行CT及X光检查。结果 2－3个月后出现骨疏松的病人113例，3－4个月后出现骨疏松的66例，未见骨疏松的21例。结论 骨折2－3个月后复查病人，应适量降低CT的窗宽，窗位和X线的照射剂量。     

Uncertainties associated with Ra and Ra measurements in water via a Delayed Coincidence Counter (RaDeCC)

The short-lived radium isotopes, ²²³Ra (T_1/2 = 11.4 days) and ²²⁴Ra (T_1/2 = 3.66 days), have been successfully used as tracers of several environmental processes, e.g., submarine groundwater discharge, coastal mixing processes, and water residence times. In this paper, the uncertainties associated with ²²³Ra and ²²⁴Ra measurements using a Radium Delayed Coincidence Counter are determined on a detailed error propagation basis with a confidence interval of 1σ. From the data analyses of several groups of coastal water samples, the calculated relative uncertainties averaged 12% for the ²²³Ra and 7% for the ²²⁴Ra. These uncertainties can decrease for radium-enriched groundwater samples although asymptotic limits have been found at 7% relative uncertainty for ²²³Ra and 4% for ²²⁴Ra. In this paper, the influence of sampling and measurement parameters on the final radium uncertainties is evaluated in order to provide guidance to optimize these factors and obtain more reliable results.     

潜水延迟给水理论模型探讨

基于对失饱和带毛管与潜水流间交互作用的分析，提出了以“失水带迟后反应”模式计算延迟给水下的定降深流动①的成因方法。它能自然地解释水位、水头的Ｗａｌｔｏｎ三阶段演变规律，且拟合实测资料，具较强实用性。现行的纽曼代表性模型未能考虑延迟给水作用，因而其水位计算结果与实测线型相反．博尔顿法是经验性的，未予揭示该现象成因。本法基本上解决了上述问题。文后图示了各参变量对水头时空分布的影响。验算表明，将本法用于潜水出流试验推求含水层参数，可获更佳结果。     

1961-2010年黑龙江省水稻延迟型冷害时空变化特征

利用1961-2010年黑龙江省62个气象站资料,基于5-9月平均气温和水稻冷害等级行业标准,利用累积距平和小波分析等方法分析水稻延迟型轻度、中度和严重冷害的空间分布特征及时间变化规律,以期为水稻延迟型冷害的研究提供基础。结果表明：1961-2010年黑龙江省水稻延迟型冷害主要集中发生在黑河、齐齐哈尔、哈尔滨东部、牡丹江西部和三江平原东部地区。1961-2010年黑龙江省水稻延迟型冷害存在明显的阶段性变化,1994年后转入新的较少发生阶段,2000年后黑龙江省水稻延迟型冷害发生明显减少。黑龙江省水稻延迟型轻度冷害和中度冷害存在21 a和9 a左右的变化周期,水稻延迟型严重冷害存在21 a左右的周期变化。     

黑龙江省延迟型低温冷害气候指标研究

针对影响黑龙江省农业生产的延迟型低温冷害,探讨前人提出的东北地区低温冷害气候指标在黑龙江省的适用性,借鉴前人经验,考虑玉米和水稻种植面积不断北扩等因素,确定黑龙江省延迟型性低温冷害气候指标的技术路线、判识临界值和计算方案。利用1961-2012年黑龙江省27个气象台站5-9月平均气温,以热量指数距平冷害判识指标为参照,考虑低温冷害指标与纬度、经度和海拔高度的密切关系,采用逐步回归法建立黑龙江省延迟型低温冷害气候指标;经过验证,表明该指标判识的低温冷害年与黑龙江省低温冷害的实际和发生规律相符,可作为监测指标;该指标所需数据量小,计算简便,具有实用性和推广价值;可采用该指标对黑龙江省低温冷害的历史发生规律进行分析。     

Testing dendrogeomorphic approaches and thresholds to reconstruct snow avalanche activity in the Făgăraş Mountains (Romanian Carpathians)

Snow avalanches are a widespread natural phenomenon in steep mountain environments, where they modulate landscapes and frequently disturb forest stands. Such disturbances in trees have been used since the 1970s to retrospectively date avalanches, study their extent and reach, as well as to document their triggers. Although virtually every dendrogeomorphic paper is still based on the concepts established by Shroder (1978), important methodological improvements have been achieved in the field ever since and more particularly over the last decade. This study therefore reports on recent methodological progress and employs three different approaches (i.e. Shroder index value and Kogelnig-Mayer weighted index value) and different sets of signals in trees (i.e. inclusion of tangential rows of traumatic resin ducts as evidence of past avalanching) to record snow avalanche activity. Using 238 increment cores from 105 Picea abies (L.) Karst trees which colonize a snow avalanche path in the Romanian Carpathians, we illustrate possibilities and limitations of the different approaches for the period covered by the chronologies (1852–2013). In addition, we sampled 30 undisturbed P. abies trees from a forest stand north of the avalanche path, where no geomorphic disturbance was identified, so as to build a reference tree-ring chronology. The three avalanche chronologies constructed with the disturbed trees allow identification of past process activity, but results differ quite considerably in terms of avalanche frequency, number of reconstructed events and their temporal distribution. Depending on the approach used, 15 to 20 snow avalanches can be reconstructed, with the best results being obtained in the dataset including tangential rows of traumatic resin ducts. The addition of this anatomical feature, formed after mechanical impact enlarges the number of growth disturbances by 43.5%, and can thus explain the increase of reconstructed avalanches by one-third as compared to the results of the chronology using the “conventional” Shroder approach.     

胸部创伤X线-CT诊断

本文对临床资料完整的５０例胸部创伤进行了Ｘ线与ＣＴ检查的对比分析，着重讨论了闭合性及开放性胸部创伤的ＣＴ征象。作者观察到Ｘ线检查在反映胸部全貌，肋骨骨折时优于ＣＴ扫描，而对Ｘ线未能发现的肺轻度挫伤、出血、少量气胸、心包积液、膈疝等，ＣＴ能做出明确诊断；还发现Ｘ线片所见到的脊柱旁长条状“纵膈气肿”实为脊柱旁的气胸影象。对Ｘ线检出的胸部阴影不能定性的，ＣＴ能区别为肺挫伤、肺血肿、肺囊肿、胸壁血肿等病变，为临床提供了较平片更加准确的放射诊断。对合并肝、脾、肾、肠等腹部脏器破裂的复合伤及骨盆、脊椎骨折等也可快速完成     

CT在诊断小儿颅脑内出血中的应用

本文报告经CT 诊断的84例小儿颅脑内出血。CT 主要表现是颅脑内出血的高密度影。CT 扫描可确定出血的部位、数量和大小等,足一项十分有价值的检查方法。     

硬膜下血肿的CT表现与预后

硬膜下血肿是常见的脑部外伤性病变之一。本文对我院１９８９年３月至１９９３年６月间收治的２５８例硬膜下血肿患者作了系统分析，对硬膜下血肿的ＣＴ表现与预后关系作一初步探讨。     

Numerical versus field studies of delayed yield in response to a moving water-table

As pumping proceeds in an unconfined aquifer the water-table is lowered and slowly drains out of the initially saturated material giving a delayed yield from storage. Although considerable work has been carried out on delayed yield, a definitive solution is still lacking. The unsaturated zone was treated here as a significant factor in delayed yield analysis. The one-dimensional unsaturated flow equation was solved numerically to simulate the flow in the zone located between successive water levels in the unconfined aquifer for the case with zero flux at the upper boundary. The moisture content distribution curve was integrated numerically to determine the amount of water drained with time. The study shows that the numerical results are in close agreement with the monitored field data, which implies the important role of the unsaturated zone and the reliability of the numerical simulation in describing this physical phenomenon. The results show that the relationship between the flux and time is sensibly in exponential form, which agrees with the general applicability of Boulton's assumption.