西北地区古代生土建筑物冻融风蚀机理的实验研究

西北地区独特的旱寒条件, 一方面使古代生土建筑物得以建筑和保存, 另一方面, 强烈的冻融风蚀作用致使许多生土建筑坍塌殆尽, 导致这一不可再生资源的破坏. 通过对古代生土建筑物冻融风蚀的模拟实验, 研究发现, 冻融风蚀是古代生土建筑物毁坏的主要因素. 当冻融次数相同, 随含水量增加, 风蚀强度增大, 尤其是当含水量相同条件下, 随冻融次数的增加, 风蚀量显著增大. 因此, 反复冻融循环作用所引起的土体微结构破坏是古代生土建筑物毁坏的主要原因, 而风蚀又是其主要动力机制. 风洞模拟实验结果表明 , 5%LS和10%PS耐冻材料具有良好的抗蚀性, 因此, 在自然条件严酷的西北地区, 采用该防护材料是对古代生土建筑物进行科学保护的一种重要途径.     

略论位(重力)基数测量在水利建设中的应用

为改变西部干旱缺水,在西部大开发中,大规模、长尺度地兴修水利,如南水北调,将有必要进行。基于同一个水准面上高程相同的原则,本文强调在上述工程的设计施工时应该使用与位基数意义相同的力高高程。据计算,在纬度差为12°,高差相差的近2500m的同一条测线上,现行的高程与力高高程相差7m之多,这样大的偏差是不能忽略的。文中对高程测量中重力点的布设及重力内插的精度等也提出了新的看法。     

地源热泵技术及其发展

地源热泵主要由四个部件组成：即压缩机，冷凝器，膨胀器和调节阀，而地热泵系统的设计主要包括地上和地下系统的设计，地下系统有开放式，封闭式和混合式三种，可根据实际情况来选择；地上系统的设计主要有风机盘管,地板式采暖系统，混合散热系统和中央空调系统的设计。     

Winter stemflow nutrient inputs into a southern New England broadleaved deciduous forest

Stemflow leaching from the above‐ground vegetative surfaces of broadleaved deciduous canopy trees has been well documented during the growing season. Winter stemflow leaching from the leafless crowns of deciduous trees is less well understood, especially in the context of global climate change. Boreal and northern temperate forests are forecast to have a lower incidence of snow events and an increased frequency of rain and mixed precipitation events. A change in the seasonal precipitation regime may be significant due to linkages among global change, stemflow leaching, and biogeochemical processes. The aim of this paper is to (1) demonstrate the extent of winter stemflow nutrient leaching from deciduous trees; (2) explore how winter stemflow leachate quantity may vary as a function of the type of precipitation event; and (3) quantify the extent to which an increase in the incidence of snow‐to‐rain events would enhance stemflow leaching. Measuring meteorological conditions, stemflow volumes, and stemflow chemistry over two successive winter seasons in New England demonstrated that winter stemflow drainage was significantly enriched compared to the incident bulk precipitation: 162 times greater for K+, 44 times greater for Ca2+, and 29 times greater for Mg2+. Snow‐to‐rain events leached considerably greater quantities of base cations from the deciduous trees than all other types of precipitation events. An increased frequency of snow‐to‐rain events from 13.8% to 25% of winter precipitation events would substantially increase mean stemflow nutrient inputs to the bases of forest trees during winter. Implications for significantly increased winter stemflow leachate inputs, corresponding to an increased incidence of snow‐to‐rain events, include a shift in the biogeographic range of species, delayed leaf emergence, and increased soil respiration.     

坐标参数加权平差法在线路补测中的应用

在线路施工的补充测量控制中,对先期控制点老坐标的如何使用,关系到新坐标的网形精度和与老坐标的差异程度.介绍了对先期控制点坐标进行赋权参加平差的方法,并给出评定结果的指标.用实例分析验证了这种方法的有效性.     

谈太阳高度角在处理建筑纠纷中的应用

根据太阳高度角公式，地球自转原理、利用立体几何知识求算出楼房高度与最低日照要求下的间距比值，从而为解决建筑采光纠纷提供技术数据。     

RESPONSE OF THE ATMOSPHERIC GENERAL CIRCULATION TO WINTER SNOW COVER ANOMALY

In this paper,the response of the atmospheric general circulation to winter anomalous snowcover was investigated through observations studies and model simulation.Results from the observations show that:(1)the anomalous winter snow cover in theextratropics of Eurasian Continent bears an intimate relation to the contemporary atmosphericgeneral circulation.The positive anomaly of winter snow cover is usually accompanied by positiveatmospheric EUP teleconnection pattern and stronger East Asian winter monsoon:or vice versa.(2)The linkage between them suggests that the abnormal winter snow cover has an importantimpact on winter atmospheric general circulation.The anomalous snow cover pattern can lead tothe anomaly of winter atmospheric EUP teleconnection pattern and thus influence East AsianWinter monsoon.With NCAR CCM2 including BATS land surface scheme,three groups of experiments wereperformed to examine the atmospheric response to the anomalous snow cover pattern and explorethe relevant mechanism.Simulated results agree well with the observations,which testify thesignificant response of the atmosphere to snow cover anomaly.It is found that the radiative coolinginduced by anomalous snow cover plays an important role in above processes,and the feedback oflong-wave radiation can not be neglected.     

Interannual and Interdecadal Variability of Winter Precipitation over China in Relation to Global Sea Level Pressure Anomalies

Based on the method of rotated principal component (RPC) analysis and wavelet transforms, the win-ter precipitation from 36 stations over China for the period 1881-1993 is examined. The results show thatthe three leading space-time modes correspond, in sequence, to winter rainfall anomalies over the reaches ofthe Yangtze River, the bend of the Yellow River, and the northeastern region of China. The three modes ex-hibit interannual oscillations with quasi-biennial and 8-year periods as well as interdecadal oscillationswith 16- and 32-year periods. The interannual oscillation (＜ 10 years) occurs in phase over the differentareas, and its maximum amplitude migrates northward considerably with prominent interdecadal variations.However, the interdecadal oscillations (10-32 years) are out of phase over the different regions, and theamplitude variations have the characteristics of stationary waves.The rainfall anomalies appear to be closely re lated to the anti-phase changes of mean sea-level pres-sure (SLP) over the Asian mainland and the North Pacific. When the SLP rises over the North Pacific anddecreases over the Asian mainland, the precipitation over East China increases noticeably. The linkage be-tween the rainfall over China and the SLP anomalies apparently results from the strength of the East Asianwinter monsoon and its associated temperature and moisture advection.     

山洞电源、信号线路改造与接地网建设相关技术探讨

本文对铁岭地震台在山洞电源，信号线路改造与接地网建设中遇到的问题及解决的办法做简要介绍，依据洞室固有条件，结合《规范》要求，探讨了监测环境建设施工经验。     

岩土工程施工监测信息系统初探

岩土工程施工监测信息系统（GeoMIS）主要以隧道、基坑和边歧工程施工监测为应用现象，运用工程可视化技术与地理信息系统GIS的全新思想，将数据库管理、分析预测与测点图形功能三者无缝集成，实现了以测点地图为中心的查询和数据输入输出的双向可视化，并提供监测概瞀和图形报表等完整的实用工具。系统功能齐全，交互灵活，无需其它应用软件系统支撑，对工程施工设计与科学研究具有实用价值。