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Search Results: 1 - 10 of 67412 matches for " 曹云 "
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无穷的概念与实数理论问题—数学基础中的两个基本问题
Questions of Concept on Infinite and Theory of Real Number—Two Fundamental Questions in Mathematical Foundations
 [PDF]

曹俊,
Pure Mathematics (PM) , 2012, DOI: 10.12677/PM.2012.24032
Abstract: “无穷集合是完成了的事物”的实无穷观点必须取消;无穷的实用意义是“无有穷尽、无有终了的”。常量性无穷大是不存在的假无穷。自然数集合是一个极限性质的、不能被人构造完毕的理想集合。无尽小数的实用意义是无穷数列的简写。所有理想实数都是康托尔基本数列的极限。理想实数的加、减、乘、除运算是极限性质的运算。
 The point of view of “infinite aggregate is finished object” on “actual infinity” must be eliminated. The meaning of infinite to use is has not the end. The infinity meant constant is the false infinity which have not exist in real world. The set of natural number is an ideal set which is a limit quality set and could not be end to constitute by mankind. The meaning of infinite decimal to use is the simple writing of infinite sequence. The ideal real numbers are all the limit of Cantor’s fundamental sequence. The calculation of addition, subtraction, multiplication, division is the limit property calculation.
初等几何的实践性基础及其应用———几何学的产生
Practicalities Foundations of Elementary Geometry and Its Applications———The Produce of Geometry
 [PDF]

曹俊,
Pure Mathematics (PM) , 2013, DOI: 10.12677/PM.2013.36052
Abstract:
现行几何理论与实践是有差距的。现行几何理论中的点、直线、平行线、射线、平面都具有理想性。它们分别是误差界趋向于零时近似点、近似直线、近似射线、近似平行线、近似平面序列的极限。极限具有不可达到的性质,所以理想点、理想直线、理想射线、理想平行线、理想平面的存在唯一性和理想合同性都需要用公理的方法去确定。在三维现实空间研究中,对于理想几何元素,欧几里德体系下的初等几何是适当的、需要的;但在应用这个理论于现实问题时,需要有一个“否定之否定”式的过程。几何公理体系的无矛盾性、公理的实际意义都是形式逻辑和数理逻辑无法解决的问题。解决这两个问题都必须使用唯物辩证法。
There is a gap between the current geometry theory and its practice applications. The point, straight line, ray, parallel line and plane in current geometry possess the character of ideal all. They are the limit of se- quence of approximation point, straight line, ray, parallel line and plane separately, when the error bounds tend to zero. But the limit possesses the characteristic that could not be arrived at. Therefore, the character of only existence and ideal congruence of ideal point, straight line, ray, parallel line and plane must apply axi- oms to affirm them. In researching three-dimensional actual space, for ideal geometry element, the system of Euclidean geometry is suitable and necessary; but it needs a process of “negation of the negation” to apply it in reality question. Two questions of consistency of the axiom system and practice function of axioms could not be settled by the method of formal logic and the method of mathematical logic. The settlement of the two questions must apply the method of materialist dialectics.
泛摆线泵油槽结构对流量特性影响分析及优化
Analysis and Optimization of the Influence of the Cavity Structure of the Pan-Cycloid Pump on the Flow Characteristic
 [PDF]

逸韬,
Journal of Aerospace Science and Technology (JAST) , 2015, DOI: 10.12677/JAST.2015.33004
Abstract:
为了使航空发动机用泛摆线泵在各飞行高度下,保持良好的容积效率的基础上,有效降低流量脉动。本文利用CFD方法,分不同工作高度,对不同油槽结构的摆线泵内流场进行仿真。发现对于高转速单级泵,可以通过沟通进油槽或同时沟通进、出油槽的方式,有效降低流量脉动。为了更好地减小压力脉动,本文对进、出油槽同时沟通的情况进行了进一步分析,发现随着沟通面积的增大及油槽间距的缩短,实际流量呈先上升再下降的趋势,流量脉动呈先急速下降再缓慢上升的趋势。证明合理的选择沟通面积及油槽间距能保证流量,同时有效降低流量脉动。对于多级泵,通过对内转子齿数为4的两级泛摆线泵进行仿真,结果证明错相位法能够大幅降低多级泵的流量脉动。
To reduce the flow pulsation of the pan-cycloid pump of the aircraft engine effectively in different flight heights on the premise of maintaining excellent volumetric efficiency, simulations of flow field in the pan-cycloid pump of different cavity structure in different working heights are conducted with CFD method in this paper. It found that for high-speed single-stage pump, communicating inlet cavity or communicating both inlet and outlet cavity can reduce the flow pulsation effectively. Meanwhile, in order to reduce the pressure pulsation, the analysis under the situation of communicating both inlet and outlet cavity is carried out further, and we find that with the increase of the area of communication and decrease of the distance between the cavity, the actual flow rate increases at first and then declines, and the flow pulsation declines rapidly at first and then rise slowly. It is justified that this situation can reduce the flow pulsation effectively, while maintaining the enough actual flow. For multi-stage pump, through the simulation of two-stage pan-cycloid pump with 4 inner rotor teeth, it is proved that dislocation method can significantly reduce the flow pulsation of multi-stage pump.

基于网络知识学习的可信问题研究

科技进步与对策 , 2014, DOI: 10.6049/kjjbydc.2013080737
Abstract: 面对互联网信息爆炸、信任不足、知识推广受阻的形势,真实可靠性成为技术知识学习过程中的难题。提出以“热信息”为目标对象,根据学习者特点建立“预评预测推荐”方案,由可信的实体组成“推荐路径”,结合专家的权威性,利用“长效机制”来克制“共谋欺骗”。最后,对技术知识的学习可靠性进行了有益的推荐性尝试和验证。知识可信性网络知识知识推荐网络学习
新生儿感染性休克的诊治进展
Diagnosis and treatment of neonatal septic shock


- , 2017, DOI: 10.7499/j.issn.1008-8830.2017.02.001
Abstract:
直流接触器软连接触头
DC Contactor Contact with Soft Connection
 [PDF]

, 赵鹤然
Transmission and Distribution Engineering and Technology (TDET) , 2013, DOI: 10.12677/TDET.2013.21003
Abstract: 直流接触器分断过程中,电弧对触头的烧蚀作用较为强烈,导致触点间接触电阻增加,严重影响触头的使用寿命。本文在传统低压直流接触器基础上提出一种带有软连接装置和片弹簧的新型双断点触头结构。这种新型触头结构在使用过程中动、静触点间会产生带有接触压力的相对滑动,可以清除触点表面氧化物,减小接触电阻,从而实现触头自清洁功能,提高使用寿命。本文从结构形变和电–热耦合的角度分别进行了仿真分析,仿真结果体现出触头动、静触点相对滑动的过程,新触头结构可以实现自清洁功能,且温升情况合理。该方案具有体积小,成本低,开断电压等级高的优点。
In the DC contactor breaking process, the arc ablation of the contact is more intense, resulting in increased contact resistance between the contacts, which seriously affect the life of the contacts. On the basis of the traditional contactor, this paper presents a new double break point contact structure of DC contactor with soft connection and leaf springs. This new contact structure will produce a relative sliding movement with contact pressure during use, can clear the contact surface oxides and reduce the contact resistance, in order to achieve the contacts self-cleaning function, im-prove service life. The moving contact and the static contact of this new structure will produce a relative sliding move-ment with a contact pressure during use, which clearing the oxide on the contact surface, reducing contact resistance, that achieve the contact self-cleaning function, improve service life. This article makes the analysis from the perspective of structural deformation and electrical-thermal coupling. The simulation results show that this new type of contact structure contacts can effectively achieve the self-cleaning function, and the temperature rise is reasonable. The program has the advantages of small size, low cost, breaking high-voltage level.
某水电站左岸泄洪洞无压段大坍方事故处理

岩石力学与工程学报 , 1988,
Abstract: 某水电站左岸泄洪洞,全长约857m,有压段开挖直径为12.5m,出口无压段开挖断面为12×14m(宽×高).施工过程中,出口无压段曾发生冒顶坍方.坍方段的洞长为50m,高度约60m(最大高度达100m),发生位移和坍落岩石达40000m~3.这样大的坍方事故,在国内外水利水电地下工程施工中都是罕见的.经过深入的调查研究和现场试验,采用了固结灌浆法、插钎法、环形导洞法、喷锚法和钢支撑法等综合处理方法,成功地处理了这一巨大坍方事故.迄今为止,该工程己正常运行两年.本文介绍该工程坍方处理经过.
一种局地非线性气候动力统计模型及其预报试验
,
高原气象 , 2002,
Abstract: 根据反演建模理论,在引入一次样条函数的基础上,设计了一种局地非线性气候动力统计模型及其一整套反演方案。其实质是用逐段线性化的方法研究局地气候系统演化的非线性特征。作为初步试验,利用云南省18个测站1956年1月-1990年12月逐月温度距平和逐月雨量距平率的时间序列,反演得到一组近似描述云南省局地气候系统的非线性动力统计方程,应用反演获得的此非线性动力统计方程进行了云南省18个测站1991年1月-1994年12月逐月温度距平和逐月雨量距平率的预报试验。试验结果表明,温度距平和雨量距平率的拟合准确率分别约为78%和64%;温度距平和雨量距平率的外推预报准确率分别为75%和63%。表明此模型具有一定的拟合和预报能力,同时具有良好的稳定性。
一种局地非线性气候动力统计模型及其预报试验
,
高原气象 , 2002,
Abstract: 根据反演建模理论,在引入一次样条函数的基础上,设计了一种局地非线性气候动力统计模型及其一整套反演方案。其实质是用逐段线性化的方法研究局地气候系统演化的非线性特征。作为初步试验,利用云南省18个测站1956年1月-1990年12月逐月温度距平和逐月雨量距平率的时间序列,反演得到一组近似描述云南省局地气候系统的非线性动力统计方程,应用反演获得的此非线性动力统计方程进行了云南省18个测站1991年1月-1994年12月逐月温度距平和逐月雨量距平率的预报试验。试验结果表明,温度距平和雨量距平率的拟合准确率分别约为78%和64%;温度距平和雨量距平率的外推预报准确率分别为75%和63%。表明此模型具有一定的拟合和预报能力,同时具有良好的稳定性。
应用非线性振荡理论研究云南局地气温的演变规律
,
高原气象 , 2004,
Abstract: 将描述局地气温变化的非线性振荡方程应用到云南省17个测站局地气温演变研究中,根据各测站1958年1月-2000年12月逐旬气温距平资料和反演理论获得具体描述各测站局地气温变化的非线性振荡方程。以经典非线性振荡理论为依据,研究了云南省17个测站的局地气温演变规律。结果表明,云南局地气温系统是弱的非线性系统;其演变的固有周期大致在6~10旬之间;在无外源强迫的条件下,云南局地气温振幅随时间增加总是衰减;考虑外源强迫的作用后,云南局地气温系统在其演变过程中只随外源强迫的振荡而振荡。应用反演获得的描述各测站局地气温变化的有外源强迫非线性振荡方程做出未来云南局地气温演变趋势预报,其平均预报准确率约为78.9%。说明该模型具有良好的预报能力和预报稳定性。
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