共查询到20条相似文献,搜索用时 375 毫秒
1.
设计了一种以CAN总线作为综合信息传输的家庭无线烟雾智能报警系统.该系统采用ARM S3C2440作为主控芯片,CAN节点作为数据交换模块,完成家庭烟雾报警功能.其中烟雾报警模块与CAN之间采用ZigBee进行无线数据传输.整个系统中ZigBee无线模块与CAN总线相结合,具有灵活、智能和稳定等优点. 相似文献
2.
摘要:针对现有消防报警系统投资大、安装麻烦等缺点,自主研发了一种基于无线通信的火灾智能化自动报警系统。主机采用STM32F103V8处理器为主控单元,实现仪器操控、无线收发、报警指示、远程控制及工作状态显示等功能。终端机以STC12C增强型51单片机作为数据处理单元,实现烟雾及温度探测和无线收发等功能。技术创新体现为基于无线通信技术并融合传感器技术和智能控制技术。总体设计依据分布式控制的思想,硬件采用单主机对应多路检测终端的一对多无线通信系统,主机依据系统软件以群发单收的方式实现一对多的同频率无线有序编码通信。依据自拟通讯协议采用串行半双工无线通信的方式实现主机与各检测终端交互。 相似文献
3.
孙小春 《海南大学学报(自然科学版)》2013,(3):254-256
对现有火灾报警系统进行了分析和研究,提出了一种基于单片机的无线火灾报警系统.该系统利用单片机控制无线通信模块进行火警信息的无线远程传输,从而进行报警,并改进了以往报警系统投资大、工程量大等缺点. 相似文献
4.
陈源 《新乡学院学报(自然科学版)》2009,26(5):29-31
针对现有的分布式火灾报警系统投资大、安装麻烦、工程量大等缺点,设计了1种基于单片机的无线火灾报警系统。系统上位机采用AT89C51单片机作为主控芯片,可分为主控模块、存储模块、人机对话模块(包括液晶和键盘)和无线射频通信模块。系统下位机以PIC18系列单片机作为主控芯片,可分为主控模块、烟感探头以及无线射频通信模块。该系统具有很好的可靠性和实时性,具有广泛的市场前景。 相似文献
5.
6.
针对传统火灾报警系统在布线、扩容等方面的不足,在无线火灾预警产品缺少的现状下,利用无线传感器网络技术和多传感器融合技术设计了一个无线火灾概率分级预警系统;该系统采用ZigBee技术快速建立星形预报警网络,节点扩充容易,根据多传感器融合信息,将火灾发生趋势按概率等级给出预警;经过试验验证,能够适应各种复杂环境的火灾预警和报警要求. 相似文献
7.
文章介绍了无线火灾自动报警系统硬件部分组成.利用无线智能火灾报警器,火灾报警控制器,声光报警器,短信模块及ZigBee通讯技术研制构建了无线智能火灾报警系统.利用LabVIEW软件平台研制开发了无线智能火灾报警器的软件部分,其中多语音通道声光报警及短信报警方式的联合使用为智能报警的实现提供了基础. 相似文献
8.
9.
10.
11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness. 相似文献
12.
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly. 相似文献
13.
QING Hai-ruo 《成都理工大学学报(自然科学版)》2004,31(6)
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction. 相似文献
14.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。 相似文献
15.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death. 相似文献
16.
YUJia-shun HEZhen-hua 《成都理工大学学报(自然科学版)》2004,31(6):694-698
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod… 相似文献
17.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying. 相似文献
18.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time. 相似文献
19.
Miao Maosheng 《华南师范大学学报(自然科学版)》2014,(6)
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula- 相似文献
20.
Yang Weitao 《华南师范大学学报(自然科学版)》2014,46(6):137-138
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re- 相似文献