普通栽培稻×小粒野稻F_1酯酶同工酶研究     

陈景  张建中  刘康平 《广东海洋大学学报》1998,(1)

用二倍体普通栽培稻和异源四倍体小粒野稻及其杂种一代（F1）进行酯酶同工酶测定和主要性状的田间表证。结果表明：普通栽培稻与小粒野生稻由于亲缘关系较远,其遗传基础差异很大,从而致使两者的酯酶同工酶谐相差也很大。两者杂交的F1,集中显示出双亲的所有酶带。F1的酶带是由于双亲互补的多个结构基因通过一系列调控机制而表达的结果。  相似文献   

对T63L16所作月延伸预报准确率的评估   总被引：2，自引：0，他引：2  

张存杰  董安祥 《气象》1998,24(10):38-42

对国家气候中心１９９６年１－１２月和１９９７年１－８月用Ｔ６３Ｌ１６模式所做的５７次月延伸预报５００ｈＰａ高度场进行了检验评估,并对 系统性误差进行了分析和订正。同时对西北气候变化有较大影响的在循环流系统的环流特征量进行了检验,并给出了订正偏差。  相似文献   

Late and post-glacial history of meromictic Längsee (Austria), in respect to climate change and anthropogenic impact     

Roland Schmidt  Sybille Wunsam  Ursula Brosch  Jan Fott  Andrea Lami  Heinz Löffler  Aldo Marchetto  Harald W. Müller  Miroslava Pražáková  Bernd Schwaighofer 《Aquatic Sciences - Research Across Boundaries》1998,60(1):56-88

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Biological and ecological characteristics of Tamarix L. And its effect on the ecological environment     

张道元  尹林克  潘伯荣 《中国科学D辑(英文版)》2002,45(Z1)

Through studying biological and ecological characteristics of Tarnarix L., we foundwide adaptability to different ecological environment and high endurance of adversity. Whenplanted in the edge of desert and periphery of oasis, Tamarix will act as excellent sand-fixingshrubs, improve ecological environment and play a positive role. However, introducing Tamarixunreasonably will deteriorate the ecological environment and reduce biodiversity and play a nega-tive role. Grasping the biological and ecological characteristics of Tamarix will do much to benefitfurther developing and utilizing of the resources.  相似文献   

一类非线性积分方程在Lp(p>0)中的最小解     

杨光崇 《成都信息工程学院学报》1999,(2):0

获得了一类非线性积分方程在Ｌｐ中的最小解,方法上不同于目前的有关文献。  相似文献   

L波段高空探测系统的时差及其测量不确定度     

梁静舒  王海深  胡姮 《气象科技》2021,49(5):681-686

通过分析L波段高空探测系统的时序设计原理,进行GTS1型探空仪与RS92型探空仪的同球比对施放试验验证,确定了由L波段高空探测系统的时序设计造成的测量元件感应气象要素至地面设备计算机软件赋时之间的时间差,会造成测量结果的随机波动。L波段探空系统总体时差对气压测量影响较大,对温度的影响较小,对湿度的影响较为复杂;由此造成的气压不确定性,将影响探空应用文件的准确性。相对于测量元件的感应时间总是延迟的,其总体散布中心为测量元件感应气象要素后1.2s,时差散布的扩展不确定度为0.98s,气压误差最大可达0.86hPa。北斗-GPS双模式导航测风探空仪的设计中采用了消除时差的方法,大大减小了测量结果的随机误差,并且在2013年12月中国气象局阳江试验中效果良好,为该问题提出了改进方法。  相似文献   

基于NB-IoT技术的小型自动气象站监测系统设计   总被引：1，自引：0，他引：1  

张李元  左少华  江锦春 《气象科技》2020,48(6):816-822

针对传统气象站通信组网技术复杂度高、建站成本高、时效性差、功耗高等缺点，设计了一种基于NB IoT技术的小型自动气象站监测系统，该系统主要由气象传感设备、单站控制器及物联网云平台组成。该系统以低功耗Corter M3内核的STM32L152微控制芯片为硬件核心，依托气象传感器设备，实现气象要素数据的采集和处理；利用NB IoT技术实现气象站和云端服务器之间的数据传输；利用RESTful API和MySQL技术，实现用户交互、远程终端控制、数据存储、数据显示、数据分析、数据查询等功能。测试结果表明，该系统建站简单、功耗低、数据传输稳定，可实现对气象要素的远程实时监测。  相似文献   

Effect of sand burial depth on seed germination and seedling emergence of Calligonum L. species     

Calligonum 《Journal of Arid Environments》2002,51(4):603

A greenhouse study was conducted to determine the effects of sand burial on seed germination and seedling emergence of ten Calligonum L. species. The results suggested that the deeper the seeds in sand, the lower and slower their germination and seedling emergence. Seedling emergence occurred from a maximum depth of 12 cm with most seedlings emerging from 2 and 4 cm depths. The percent seedling emergence, number of days of first emergence, percent seed germination and percent of dormant seeds were significantly affected by different species and burial depth. There was a significant positive correlation between the number of days to first emergence and burial depth. Both mean percent germination and percent seedling emergence were negatively correlated with depth significantly for each species.  相似文献   

Application of Cesàro mean and the L-curve for the deconvolution problem     

L. Y. ChenJ. T. ChenH. -K. HongC. H. Chen 《Soil Dynamics and Earthquake Engineering》1995,14(5)

In this paper, the Cesàro mean technique is applied to regularize the divergent problem which occurs in ground motion deconvolution analysis in geotechnical engineering. To deal with this ill-posed problem, we use the corner of the L-curve as the compromise point to determine the optimal order of Cesàro mean so that the high frequency content can be suppressed instead of engineering judgement using the concept of a cutoff frequency. The fractional order of Cesàro mean has been derived and used to fulfill this purpose. From the examples shown, it is found that the wave form including maximum acceleration can be accurately predicted and that both the high frequency content and divergent results can be avoided by using the proposed regularization technique.  相似文献   

Performance of a parallel finite difference atmospheric general circulation model 1     

Zhang Xin  Wang Bin  Ji Zhongzhen 《大气科学进展》2001,18(6):1175-1184

A new version of the Institute of Atmospheric Physics (IAP) 9-Layer (9L) atmospheric general circulation model (AGCM) suitable for Massively Parallel Processor (MPP) has been developed. This paper presents the principles of the parallel code design and examines its performance on a variety of state-of-the-art parallel computers in China. Domain decomposition strategy is used to achieve parallelism that is implemented by Message Passing Interface (MPI). Only the one dimensional domain decomposition algorithm is shown to scale favorably as the number of processors is increased. This work is partly supported by the National Natural Science Foundation of China (Grant Nos. 49775268 and 49823002), the China National Key Development Planning Project for Basic Research (Grant No. G1998040905) and the CAS Key Innovation Direction Project (Grant No. KZCX2208).  相似文献