C++虚拟继承状态下对象复制语义的分析研究

分析C 虚拟继承状态下的对象复制语义学.通过分析当前主流C 编译器对这个语义的支持情况,比较了它们之间实现上的差异;最后提出一种基于软件编码的实现方案,并比较了各种方案的性能优劣,以求更大限度的发挥C 的性能.     

基于Atmega16的多点温湿度测控系统设计

介绍了基于Atmega16单片机为检测和控制核心,并同多个数字温度传感器DS18B20及模拟湿度传感器HS1101构成温度与湿度的测控系统.给出了系统的总体设计方案、硬件设计及软件框图.所设计的粮情测控系统具有优良的性价比,通过系统软硬件的联合调试说明,该系统可以满足对温湿度及烟雾进行实时监控的需要,具有稳定性好、精度高等特点,有一定的应用价值.     

一九三五年八月德国气象学会会议纪要

德国气象学会,每两年举行会议一次,其先已於一九三一年及一九三三年分别在维也纳及汉堡举行。今年八月二十五日至二十七日为第十九次会期,假但泽高等工业学校开会,与会者除德人而外颇多外人。其演讲多属天气与大气之各种现象,兹择要略纪如下。会议开幕时,由主席枢密顾问明兴Schmauss教授演讲“气象学之术语”。略谓:吾人皆知气象界须有统一之国际符号,以为发表工具,使逐日印行之天气图与各处之年报,均有同一之记载。教授继谓气象学上基本术语,应有对外对内之分,前者吾人仅需知其国际简单意义,而後者则更需通晓其文字之说明。此外,吾人更须切实互助,     

民国二十五年九月份各地气象通讯

广州:本月天气,晴雨分布,极不均匀,上旬各日均雨,下旬晴朗乾燥,滴雨全无,中旬多雾,晴云日数相等。雨量共计151.3公厘,上旬占116.1公厘;七日雨量最多33.9公厘,雨量超过10公厘者凡7日。最特别者,下旬湿度甚低     

SPATIAL-TEMPORAL ANALYSIS OF REGIONAL DISPARITIES OF INTERNET DEVELOPMENT IN CHINA

This paper attempts to summarize the disparities of lnternet development in China spatially-temporally. The major objective is to measure the differences between Eastern, Central and Western China. Methods of map presentation, correlation, Lorenz curve, Gini Coefficient and location quotient analysis are conductcd in this study.For convenience, the indicator of regional lnternet development is simplified as the number of domain names registered under .CN in each province. The data used are collected from the semi-annual surveys of the Statistical surrey Report on the Internet Development in China since 1999. There are several findings: 1)The number of domain names in each province (city) declines gradually from the east to the west. 2) The gap between the highest growth provinces (cities) and the lowest ones is rather large. 3) Although the absolute differences between the eastern, ccntral and western China have been enlarged, the relative diffcrences in each province (city) have remained constant.4) Provinces (cities) are classified into three types according to location quotient changes, namely, rising type,changeless type and declining type. Compared with industrial and economic growth, lnternet sector in the eastern and western China is relatively ascending, while that in the central China is descending. 5) The number of domain names at provincial level is not statistically consistent with GDP.     

Influence of Seawater Temperature on Phytoplankton Growth in Jiaozhou Bay, China

The phytoplankton reproduction capacity (PRC), as a new concept regarding chlorophyll-a and primary production (PP) is described. PRC is different from PP, carbon assimilation number (CAN) or photosynthetic rate ( P^B ) . PRC quantifies phytoplankton growth with a special consideration of the effect of seawater temperature. Observation data in Jiaozhou Bay, Qingdao, China, collected from May 1991 to February 1994 were used to analyze the horizontal distribution and seasonal variation of the PRC in Jiaozhou Bay in order to determine the characteristics, dynamic cycles and trends of phytoplankton growth in Jiaozhou Bay; and to develop a corresponding dynamic model of seawater temperature vs. PRC. Simulation curves showed that seawater temperature has a dual function of limiting and enhancing PRC. PRC‘s periodicity and fluctuation are similar to those of the seawater temperature. Nutrient silicon in Jiaozhou Bay satisfies phytoplankton growth from June 7 to November 3. When nutrients N, P and Si satisfy the phytoplankton growth and solar irradiation is sufficient, the PRC would reflect the influence of seawater temperature on phytoplankton growth. Moreover, the result quantitatively explains the scenario of one-peak or two-peak phytoplankton reproduction in Jiaozhou Bay, and also quantitatively elucidates the internal mechanism of the one- or two-peak phytoplankton reproduction in the global marine areas.     

干旱区几类主要地物遥感的最佳波段选择

采用t检验法比较地物间光谱反射率的差异性,选取显著性差异频数较多的波长集合作为最佳遥感波段。用新疆境内十一种有代表性的干旱区地物的光谱数据作为检验对象,在两种显著性水准上制定其光谱差异性频数表。按照能区分8成以上地物的要求,并考虑适当加大光谱能量,排除大气吸收的影响,提高监测植被动态效果,选取510-610nm、620-690nm、770-930nm、950-1100nm作为干旱区几类主要地物遥感的最佳波段。检验数据的置信度在95%以上。有93%显著性差异数据的置信度达到99%。用F检验法选择波段,得到非常相近的结果,进一步证明所选波段的可靠性。     

民国三十年一月至三月全国天气概况

一月一月为苦寒之月,但在本年中国各地大抵较往昔温暖,绥西气候反常,黄河解冻,冰凌下流,其未解冻之处,冰面淹水二三尺深,阻断交通,华中与华南亦显有温度之增进,惟东北一带气候转寒。月之二十四日及三十日吉林附近清晨之气温皆达摄氏冰点下三十度,寒冷之甚可以想见。欧洲方面月初亦觉奇寒斯堪的纳维亚半岛为北冰洋寒流所袭,波罗的海海上有大风雨,法境大雪,维琪气温降至冰点下二十度,称这一八八○年来未有之奇寒。天气之演变大有东西相映之局。