下界
- 与 下界 相关的网络例句 [注:此内容来源于网络,仅供参考]
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If all the flows getting into the system were constrained by the leaky-bucket parameters, the maximum cell delay and the buffer content bound were got when the capacity of the crosspoint was enough, and the maximum cell delay and the buffer capacity bound which can guarantee the maximum cell delay were also got when the content of the crosspoint was not enough.
在各数据流都由令牌桶参数约束的条件下,得到了交叉点缓存容量足够大情况下的最大信元时延和缓存临界容量大小,还得到了交叉点缓存容量不足够大情况下的最大信元时延以及保证信元具有时延上界的缓存临界容量大小。
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The effect of tribology factors on bearing vibration is studied experimentally. AR model and WPT are used to processing the normal arid abnormal signals. The results are as follows:1. The vibration of ball bearings is caused by the tribology action of contact pairs of ball and ring races and has the essential of tribo-dynamics. Any factors affecting the tribology characteristics of contact pairs will affect vibration and noise of bearings consequently.2. Vibration characteristics of bearing keep almostly unchanged with the increasing of axial load expecting the increasing of nature frequencies. When radial load increasing with axial load unchanged, nature frequencies keep unchanged but some new vibration peaks appears in the spectrum.3. Vibration amplitudes are damped and nature frequency are enhanced with sufficient lubrication. Vibration and noise of bearings increase obviously and roar can happen and the contact surfaces scratch slightly under insufficient and unclean lubrication state. Bearing will be disabled in a few minutes without any lubrication.4. Bearing vibration is unstable under low speed. With the speed increasing, the vibration become stable and natural frequencies increase slightly but the amplitudes increase apparently.5. Bearing vibration can be excited only by some harmonics ofwaviness without lubrication and by all harmonics with lubrication based on the theoretical analysis.6. The nature frequencies of ball bearings decrease with the increasing sizes. When international clearance increasing, nature frequencies decrease in radial and increase in axial and angular and the amplitudes increase in radial and decrease in axial and angular. When the number of balls increasing, nature frequencies increase and amplitudes decrease. When the pitch diameter increasing, axial nature frequency increase and others nearly keep no change. When outer race groove curvature radius increasing, nature frequencies increase in radial and decrease in axial and angular and amplitudes keep no change in radial and increase in axial and angular. When inner race groove curvature radius increasing, nature frequencies decrease and amplitudes increase.7. The distortion in amplitude and frequency components of bearing vibration signals picked up by the present probe measurement method is founded and right conclusions cannot be achieved by the signals. When accelerometer is rigidly screwed with steel stud onto a flat outer surface of a ball bearing, vibration signal can be got without distortion and the reliability of research on bearing vibration is assured.8. AR model is suitable for large samples of bearing vibration signals, square root of length of samples can be used as the upper limitation of order determination and the FPE order selection criterion is effective. Many advantages of AR spectrum are founded over the classical based on FFT.9. Time-Frequency analysis is necessary for abnormal noise of ball bearings. WPT overcomes the principle shortcomings of STFT and proved to be a best tool to process the abnormal signals.
理论分析和试验研究表明: 1球轴承振动是钢球—滚道接触副中的各种摩擦学作用引起的,具有摩擦动力学的本质,任何对接触副的摩擦学特性有影响的因素都将对球轴承的振动和噪声特性产生影响; 2中心轴向载荷作用下,载荷增大使球轴承的固有振动频率升高,载荷越大同样的载荷增幅引起的频率升幅减小,足够大的中心轴向载荷作用下载荷的变化对球轴承振动的频率特性不会产生明显的影响; 3轴向和径向联合载荷作用下,径向载荷不大时球轴承振动的固有频率基本不变,但是可能引起变刚度激励的非线性振动,出现新的频峰,过大的径向载荷将使部分钢球脱离接触,使球轴承的振动和噪声呈现不稳定状态; 4润滑对球轴承的振动和噪声特性有重要的影响,良好的润滑对振动有明显的抑制作用,润滑不充分时,振动和噪声的水平会有明显增高,一定条件下还会激发接触副中的谐振,发出啸声,造成接触表面的伤害,无润滑干接触时,短时的运转就会损伤接触副表面,使振动和噪声迅速增大,并随时可能引发严重的磨损和卡滞失效;接触副润滑良好时,油膜的"刚化效应"使球轴承振动的固有频率有所提高,润滑剂中含有弥散性污浊时,振动的幅度总体升高,但弥散性污浊不会改变球轴承振动的频率特性;浙江大学博士学位论文:球轴承振动的研究 5低速时,球轴承振动的基本特征呈现不稳定状态,随着转速的提高,球轴承振动的频率特性趋于稳定,固有频率频峰升高; 6理论分析表明,干接触时钢球和滚道表面波纹度的某些谐波分量能激励球轴承的振动,振动的幅值与谐波幅值成正比,实际球轴承中钢球的分布不可能完全均匀,波纹度的激励作用会随时发生;润滑接触的分析表明,波纹度的任意谐波分量均能激励球轴承的振动; 7球轴承的几何和结构参数分析表明,球轴承尺寸越大,径向、轴向和角振动的固有频率越低;钢球中心圆直径增大,球轴承的径向和轴向振动的固有频率基本不变,角振动的固有频率有所上升,振动的幅频特性基本不变;径向游隙加大使球轴承的径向振动固有频率降低,轴向和角振动的固有频率有所升高,径向振动幅频特性的幅值升高,而轴向和角向降低;钢球的数量增多使球轴承振动的固有频率上升,幅频特性的幅值下降,径向振动的幅值下降最为明显;外圈沟曲率半径系数增大使球轴承径向振动的固有频率升高,轴向和角振动的固有频率降低,径向幅频特性基本不变,轴向和角向幅频特性幅值升高;内圈沟曲率半径系数增大使径向、轴向和角振动固有频率均下降,振动幅频特性的幅值均有升高; 8试验对比表明,传感器采用探针式安装时,由于探针接触副接触特性的影响,钡(量得到的球轴承振动信号有失真,采用专门设计和制作的试验球轴承,以固定式安装加速度计,首次测量得到了球轴承振动的真实信号,通过对振动信号的分析,验证了球轴承振动的理论模型; 9)基于时间序列分析的AR模型适用于大样本球轴承振动信号的分析,以样本长度的均方根值作定阶上界,FPE做判阶准则,给出的AR谱光滑,频率分辨率高,是球轴承振动分析的简便而可靠的手段; 10以时频域分析的小波包变换分析球轴承异音信号能够比较好地定位和聚焦异音发生的时间,时间间隔,频率范围,同样是球轴承振动分析的可靠的手段,可用作球轴承故障诊断技术。
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This dissertation was focused on the research about the formation and evolution of NQB from the Late Triassic to the early middle Epoch of Jurassic Period, including integrated analyzing the characteristic of the key stratigraphic surfaces, the time of the key stratigraphy, regional rock straigraphy, biostratigraphy and chronostratigraphy, sedimentary system and depositional facies. On basis of these analysis, a tectonic evolution model have been established for NQB during from the Late Triassic to the early middle Epoch of Jurassic Period.1. After the systematic surface analysis about main stratigraphy units, we found that:(1) the bottom of Xiaochaka formation was comformity with the middle Triassic in the basin, and in the north margin it was deposited and overlapped on the different period stratigraphy before Triassic.(2) The top surface of Xiaochaka formation developed regionally karst and paleo-karst breccia, and was uncomformity with Nadigangri Formation, these things suggest that NQB in Xiaochaka depositing stage was developed from middle Triassic basin, and then an extensive regression occurred, the deposition was over and erosion come into being.(3) The lithologic assemblage, geochemistry, mixed fossils, and stratigraphy overlapping characteristic of Quemocuo Formation in early middle Jurassic indicted that the uncomformity surface was an extension-unconformity.2. Integrated analysis about stratigraphy division and correlation indicted that:(1) the paleontologic assemblage of Xiaochaka formation show its time was Carian -Norian stage of late Triassic. According to it was overlapped by late Triassic Nadigangri Formation, so Xiaochaka formation should be Carian - early Norian stage.(2) the SHRIMP Zircon U-Pb age of Nadigangri formation volcanic rocks wear vary form 216 to 205 Ma, so its time should be Norian, but maybe extended into Rhaetian Stage.(3) The age of its bottom volcanic rocks, the fossil assemblages of its middle and upper members and overlapped by lower Jurassic, indicted the age of Riganpeicuo Formation was Norian - Rhaetian stage. And the same time, the volcanic rocks geochemistry of Nadigangri and Riganpeicuo formation both reflected that they wear formed in rift tectonic settings. The lower lithologic and surface characteristic, fossil assemblages and its upper maybe was conformity with lower Jurassic, all reflected that the age of Tumengela Formation in Tumen area should be Norian - Rhaetian stage.
论文对晚三叠世—中侏罗世早期盆地的形成与演化开展了研究,包括关键地层界面特征分析、关键地层时代归属分析、区域岩石地层、生物地层和年代地层的综合对比分析、区域沉积体系与沉积相分析、岩相古地理分析,最终建立晚三叠世—中侏罗世早期羌塘盆沉积—构造动力演化模式。1、系统的对各地层单元的界面分析发现:(1)肖茶卡组底界在盆地内部与中三叠统整合关系,在盆地北缘为沉积超覆于不同时代的前三叠系之上:(2)肖茶卡组顶界面发育古岩溶角砾岩,与上覆那底岗日组为岩溶不整合接触,说明肖茶卡组沉积时期的羌塘盆地是在早中三叠世的盆地基础发展起来的,后期出现了广泛的海退事件,使盆地结束沉积并遭受风化剥蚀作用;(3)中侏罗统雀莫错组的岩性组合特征、岩石化学特征、古生物化石混积和地层的沉积超覆现象均表现出裂陷环境下形成的伸展不整合面的特征。2、综合地层划分与对比分析认为:(1)肖茶卡组古生物化石组合反映其时代为晚三叠世卡尼期—若利期,根据其上被上三叠统那底岗日组不整合覆盖,将其时代厘定为卡尼期—若利期早期;(2)那底岗日组火山岩SHRIMP锆石U-Pb年龄在216~205 Ma之间,其时代主要为若利期,可能包含有瑞替期:(3)日干配错组底部火山岩的年龄、中上部化石组合及其被下侏罗统整合覆盖,综合反映的时代为晚三叠世若利期—瑞替期,而且那底岗日组火山岩和日干配错组火山岩的地球化学成分分析反映两者均为引张构造背景下的产物;土门地区的土门各拉组的下部岩性及界面特征、化石组合和上部可能被下侏罗统整合覆盖,综合反映其时代为若利期—若利期。
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CuS and CdS nano-particulate films were obtained with these two methods, and some interesting phenomena were observed: under the Gibbs film formed by CTAB, CuS nano-rods were obtained at the oil/water interface, and disklike aggregates of CdS nano-crystals were obtained at both the air/water and oil/water interfaces; under the Langmuir film formed by NaAOT at air/water interface, disk-like aggregates of CdS were also obtained.
利用此两种反应技术,制备了CuS和CdS颗粒膜,并研究了它们的一些光电性质;在Gibbs膜下,得到了棒状CuS纳米晶。由发现的表面活性剂形成的带状物,提出棒状CuS晶体是以带状聚集体为模板形成的;在液-液、气-液界面Gibbs膜下反应中,发现CdS纳米颗粒的盘状聚集体的形成,这是由于表面活性剂在界面上形成的二维胶束而造成的;在气-液界面上Langmuir下的反应中,也发现CdS盘状晶体的生成。
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Results:(1) the mark of glabellar point, subnasal point,stomoschisis point, and supramentale fit the conception of "the golden point".
结果:新疆维吾尔族美貌女性面部、五官比例的特点:(1)眉间点、鼻下点、口点、颏上点4个界点中除颏上点以外,其余界点与&黄金点&基本相符。
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The central argument of this paper is that in order to tackle with various conflicts revolving around interests of different parties, Taiwanese capital, as an outside force, together with local government in Kunshan, have gradually developed a system of transborder governance over time.
本文的假设是,作为外力的台商和大陆的地方政府之间,为了解决利益纠结的各种矛盾,在一个历史的过程中,有些区域逐渐摸索、建立了一个跨界治理的系统来支援全球化脉络下的跨界生产。
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The central argument of this paperis:in order to tackle with various conflicts revolving around interests of differentparties ,Taiwanese capital,as an outsider ,together with Kunshan government,have gradually developed a system of transborder governance in a historical process.
本文的假设是,作为外力的台商和大陆的地方政府之间,为了解决利益纠结的各种矛盾,在一个历史的过程中,有些区域逐渐摸索、建立了一个跨界治理的系统来支持全球化脉络下的跨界生产。
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The basic concepts such as price, value, counting criterion have been discussed, but the discussion is rather from a practical point of view than from the analysis of its essence. There are also discussions on valuation methods, but they are just limited in the specific method used in a singular asset valuation instead of colligating and comparing the methods applied in different kinds of assets valuation.
目前对资产评估理论的研究基本上都局限于在现行资产评估理论框架下的个别问题的探讨,评估界存在对资产评估理论中价格、价值,评估计价标准等基本概念的讨论,但讨论主要从实用角度出发,少有从资产评估理论的本质出发进行分析的;评估界也存在对资产评估方法的讨论,但讨论多仅限于单一资产评估时方法应用本身,没有将方法在各类资产评估时的应用对应起来进行比较、统一。
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Modeling and stability analysis problem of linear switched system are emphasized in this part and main results include:(1) Through investigation in the projection of 〓 on x, where x denotes continuous state vector, a series of sufficient conditions for stability, asymptotic stability and unstability of linear switched system's equilibrium in the sense of Lyapunov are achieved. And also, a sufficient and necessary condition for state bounded stability of linear switched system is received.(2) For a class of periodical linear switched system whose switching sets are a group of ordinal lines starting from the original point, it's proved that state bounded stability can be defined by the running characteristic in a single period (3) Based on linear switched system, the concept of linear switched system network is put forward. Linear switched system network is a complex network interconnected by many linear switched systems.
这部分着重研究线性切换系统的建模与稳定性分析问题,主要成果包括:(1)通过考察〓在x上的投影,得到线性切换系统的平衡点在Lyapunov意义下稳定、渐近稳定及不稳定的一系列充分条件,并得到了线性切换系统状态有界稳定的一个充要条件;(2)证明了对于一类切换集为从原点出发的一组射线的周期线性切换系统,其状态有界稳定可根据一个周期内的系统运行特性来判定;(3)在线性切换系统的基础上提出了线性切换系统网络的概念,线性切换系统网络是由多个线性切换系统交互作用而形成的复杂网络。
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Prof. Long-Ruilin mentioned that if we want to study weighted inequalities for martingales, such as the maximal inequalities, the inequalities for the square operator and so on, the condition imposed on weights are mainly A〓 and S, but we don't know whether this condition is superfluous in all problems we consider. Since the condition can not be weakened for the known operators, now we consider a new operator to discuss its L〓-boundedness, then another problem arises, under what condition can we get it?
龙瑞麟先生曾经提到要讨论关于可测的鞅的极大算子、均方根算子以及条件均方根算子的L〓有界性,或它们之间的〓有界性时,所设的主要条件是A〓与条件S,有了这两个条件在讨论加权问题时基本上没有什么困难,但是要想用更弱的条件来代替它们,即使在古典情况下(此时S条件是自然满足的)也恐怕还不到时候。
- 推荐网络例句
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This one mode pays close attention to network credence foundation of the businessman very much.
这一模式非常关注商人的网络信用基础。
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Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.
扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。
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There is no differences of cell proliferation vitality between labeled and unlabeled NSCs.
双标记神经干细胞的增殖、分化活力与未标记神经干细胞相比无改变。