倒春寒的划分和预报服务探讨

本文利用预报区域1960～1995年春季逐日气象资料,分析得到了倒春寒天气的客观划分标准、气候特点、主要影响系统及其形势特征。采用较新特色的折扣回归模型,建立了三、四月份各旬倒春寒的集成预报方程;利用短期预报资料,研制出若干预报判据和消空指标,建立了短期预报回归方程,并编制出具有一定特色的预报服务系统。经1997年实际应用,倒春寒天气的预报准确率在经验预报的基础上提高20％左右。     

断层活动应力轴的确定及首都圈应力场

本文从应力应变关系的基础上给出了利用断层形变资料计算断层活动的水平主应力方向的公式,并用邢台、唐山和海城的地震断层形变资料求解了主应力方向,其结果和震源机制解一致。还用首都圈跨断层资料计算了水平主应力轴,结果表明主应力优势方向为ＮＥ５０°～ＮＥ７０°,近１０年来总趋势无显著变化     

应用数字滤波消除潮位短周期波动对确定海平面变化趋势的影响

由一元线性回归分析的正则方程计算表明,在验潮记录较短的客观条件下,验潮序列中的周期波动对确定海平面变化趋势的影响是显着的.着重讨论采用数字滤波方法消除周期小于4年的短周期波动对确定海平面变化趋势的影响,并设计了最平滤波器,其通带截止频率对应的周期为4年,即应用最平滤波器对月均验潮序列进行低通滤波,基本上可消除周期小于4年的短周期波动对确定海平面变化趋势的影响.     

Asteroid Mean Elements: Higher Order and Iterative Theories

Mean orbital elements are obtained from osculating ones by removing the short periodic perturbations. Large catalogues of asteroid mean elements need to be computed, as a first step in the computation of proper elements, used to study asteroid families. The algorithms for this purpose available so far are only accurate to first order in the masses of the perturbing planet; the mean elements have satisfactory accuracy for most of the asteroid belt, but degraded accuracy in the neighbourhoods of the main mean motion resonances, especially the 2:1. We investigate a number of algorithms capable of improving this approximation; they belong to the two classes of Breiter-type methods and iterative methods. The former are obtained by applying some higher order numerical integration scheme, such as Runge–Kutta, to the differential equation whose solution is a transformation removing the fast angular variables from the equations; they can be used to compute a full second order theory, however, only if the full second order determining function is explicitly computed, and this is computationally too cumbersome for a complicated problem such as the N-body. The latter are fixed point iterative schemes, with the first order theory as an iteration step, used to compute the inverse map from mean to osculating elements; formally the method is first order, but because they implement a fixed frequency perturbation theory, they are more accurate than conventional single iteration methods; a similar method is already in use in our computation of proper from mean elements. Many of these methods are tested on a sample of asteroid orbits taken from the Themis family, up to the edge of the 2:1 resonance, and the dispersion of the values of the computed mean semimajor axis over 100 000 years is used as quality control. The results of these tests indicate that the iterative methods are superior, in this specific application, to the Breiter methods, in accuracy and reliability. This is understood as the result of the cancellations occurring between second order perturbation terms: the incomplete second order theory, resulting from the use of a Breiter method with the first order determining function only, can be less accurate than complete, fixed frequency theories of the first order. We have therefore computed new catalogues of asteroid mean and proper elements, incorporating an iterative algorithm in both steps (osculating to mean and mean to proper elements). This new data set, significantly more reliable even in the previously degraded regions of Themis and Cybele, is in the public domain. This revised version was published online in July 2006 with corrections to the Cover Date.     

CZ—22型钢绳冲击式钻机改型探讨

本文了ＣＺ－２２型钢绳冲击式钻机改进的必要性及其在施工中出现的主要问题和原因分析、改型方案的确定和论证，ＣＺ－２２型与ＣＺ－２２Ａ型钻机的主要区别，改型机方案的实施、效果评价和论证。     

CLIMATIC CHARACTERISTICS OF NET RADIATION IN THE EARTH-ATMOSPHERE SYSTEM OVER CHINA*

Investigated are effects of the total cloudiness and other factors on earth-atmosphere net radiation(EANR) and analyzed is its relation to other components and ground surface net radiation in the context of ERBE and ISCCP.Evidence suggests that planetary scale albedo and earth-atmosphere short wave absorption radiation have maximum effect on the net radiation under study,with the influence of cloud and latitude displayed predominantly through the two factors;OLR has relatively weak effect;the earth-atmosphere net radiation is well correlated with surface net radiation.Analysis is also performed of the geographic distribution of the earth-atmosphere net radiation throughout China,and the annual curve of the net radiation on a local basis is marked by high(low) value in summer(winter) with the impact of factors.including total cloudiness responsible largely for the shift of the months with maximum.     

总磁场强度的空间相关及北黄海ML5.0级地震异常

清理攻关后，虽然相关系数法被列为地磁学科预报地震的方法之一，但应用性较差，且震例不多，为了探讨该种方法预报地震的效果，本文对辽宁地区总磁场强度进行了空间相关分析。     

旋转针锥光下一光轴出露时快速测定2V的图解

为了简化旋转针锥光下一光轴出露时测定2V的赤平投影法的绘图手续,设计了本图解,只要测取θ,R,R′与φ四值,就能更快地求得2V值。     

长短桩复合地基设计计算的探讨

通过对长短桩复合地基承载力计算的不同公式进行对比分析 ,提出比较适宜的设计方法 ,并提出其沉降计算公式和加固效果检测方式 ,并将长短桩复合地基理论灵活应用于补桩设计