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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。

In time of realizing moderate unglue hemp, it developed a series of new products like low polymeric xylose, pectin, environmental fiberboard and organic manure that reaches delamination and multilevel use of hemp's combination and disassembly.

技术特点:1、项目基于大麻纤维和麻杆等化学组成和结构的差异,开发了环境友好的汽爆新技术,为实现大麻的清洁、高效全利用奠定了基础。2、建立的大麻清洁脱胶方法,既提高了麻皮纤维的制成率和分裂度,又不损伤纤维结构,显著提高了大麻的可纺性,是一种创新的大麻脱胶技术。3、提出了利用大麻杆无胶制备环保型纤维板的方法,解决了成本高和二次污染问题。4、该项目突破依靠单一技术或单一组分利用的技术路线,按照生态工程原理,建立了大麻产品深加工利用的技术体系和综合利用新工艺,在实现麻皮纤维适度脱胶的同时,开发了低聚木糖、果胶、环保型纤维板和有机肥料等系列新产品,达到了大麻组分的分层多级利用。

objective to evaluate efficacy of extracorporeal shock wave lithotripsyfor treating ureteral stones in situ,investigate the cause of higher re-treatment rate.methods total of 687 patients with ureteral stone were received eswl between january 2000 and december 2004,included 455 male(66.2%) and 232 female(33.8%) patients,6 cases have bilateral ureteral calculi,12 cases have unilateral multiple calculi.hence,together 709 ureteral calculi were treated.patients upper ureteral calculi were treated in the supine position,for lower ureteral calculi patients were turned prone.to reduce eswl-induced renal trauma and pain,using lower energy source,adjusted power setting from 9.8 to 13.2kv,limited 1500 shock wavs per one session.no auxiliary procedure were used before eswl.the stone size was measured as the surface area of stone length by stone width on x-ray film.the interval between two treatment sessions was two weeks.results of 709 ureteral calculi,the overall stone free rate was 97.3%(690 calculi),re-treatment rate was 34.1%(292 calculi).according to the performed treatment sessions,one session 467 calculi,the mean stone size 37.27mm2,stone free rate 65.4%(464 calculi).two sessions 138 calculi,the mean stone size 62.48mm2,stone free rate 18.4%(131calculi).three sessions 52 calculi,the mean stone size 79.60mm2,stone free rate 7.1%(50calculi).four sessions 19 calculi,the mean stone size 101.63mm2,stone free rate 2.4%(17calculi).fivesessions 33 calculi,the mean stone size 119.33mm2,stone free rate 3.9%(28 calculi).overall 19 cases(2.7%)turned to other treatment modalities.of 335 upper ureteral calculi,303 achieved stone free (95.8%),re-treatment rate was 38.5%(129 calculi).of 374 lower ureteral calculi,369 achieved stone free(98.7%),re-treatment rate was 30.2%(113 calculi).the re-treatment rate of upper ureteral calculi was higher than lower ureteral calculi(p<0.05,χ2=5.40).the difference of stone-free rate between upper and lower ureteral calculi was no significant(p>0.05,χ2=0.15).conclusion eswl should be considered first line therapy for ureteral stone still.stone burden are the main variable of higher re-treatment rate,upper ureteral stone may moving with respiring during eswl.so efficinet shock wave was decreared,re-treatment rate become higher.

目的 评估体外震波碎石治疗输尿管结石的疗效,探讨再治疗率高的原因及输尿管结石的治疗选择。方法回顾2000年1月~2004年12月间eswl治疗输尿管结石的临床资料687例,男455例(66.2%),女232例(33.8%),平均年龄46.6岁(15~83岁)。有双侧输尿管结石6例,单侧多发性输尿管结石12例(4颗1例,3颗2例,2颗9例),共计输尿管结石709颗(含透光结石13颗)。应用上海爱申公司生产的desunit6030型碎石机,c臂x线球管做结石定位。上段输尿管结石(肾盂输尿管交界处至骶髂关节上缘)取仰卧位,下段输尿管结石(骶髂关节上缘下至输尿管口)取俯卧位。为减少eswl引起的肾损伤和疼痛,应用较低的能量,震波发生器电压从9.8~13.2kv,震波频率1.5s。每次治疗设定为1500次震波。治疗后3天摄腹部平片或b超,以后每隔7日重复检查。假如结石未碎或有残留结石最长径>3mm以上,再次eswl,两次治疗的间隔时间为两周。结石的大小用x线片上的表面积(mm2表示。结果 709颗输尿管结石总的治愈率为97.3%(690颗),再治疗率34.1%(242颗)。其中一次治疗467颗,平均结石大小37.27mm2,治愈464颗(65.4%),3颗改治疗;两次治疗138颗,平均结石大小62.48mm2,治愈131颗(18.5%),7颗改治疗;第1和第2次治疗治愈率(1个月治愈率)为83.8%。3次治疗52颗,平均结石大小79.60mm2,治愈50颗(7.1%),2颗改治疗;4次治疗19颗,平均结石大小101.63mm2,治愈17颗(2.4%),2颗改治疗;5次及5次以上治疗33颗,平均结石大小119.33mm2,治愈28颗(3.9%),5颗改治疗。总计19颗(2.7%)结石改变治疗方式。上段输尿管结石335颗,治愈321颗(95.8%),再治疗129颗(38.5%)。下段输尿管结石374颗,治愈369颗(98.7%),再治疗113颗(30.2%)。经χ2检验,上、下段输尿管结石的再治疗率差异有显著性(χ2=5.40,p<0.05),治愈率差异无显著性(χ2=0.15,p>0.05)。不良反应:血压升高13例(1.9%),震波区域疼痛26例(3.8%),震波进入处皮肤点状淤血33例(4.8%),肉眼血尿128例(18.6%),均于第2、3天自行消失。结论 eswl目前仍是输尿管结石的第一线治疗,结石的大小是再治疗率高的主要因素。结石的位置有影响,上段输尿管结石可随呼吸移动,有效震波次数减少,再治疗率比下段输尿管结石高。eswl前注重病例筛选可降低再治疗率。

This Al -free 980nm pump laser have many merits, such as improved catastrophic optical damage level; no degradation due to oxidation of aluminium during fabrication process and laser operation, which is desirable characteristic for multi-step growth; lower electrical and thermal resistance with GalnP cladding; better carrier confinement with GalnAsP confinement layers; Selective chemical etching between GaAs and GalnP maks precisely control for fabrication of stripe geometry lasers.· Calculated the physical parameters of ternary and quaternary III - V compoundsby interpolation formulas based on curve fits or on a linear regression, such aslattice parameter, band gap, and refractive index.· Using luttinger-kohn Hamiltonian-based propagation-matrix method presentedby S.L.

这种无Al980nm半导体激光器可以提高激光器出现腔面损伤所需的能量,消除在生长过程和应用过程中由于Al的氧化而使激光器的使用寿命缩短的问题,便于激光器的多次生长;以GaInP为盖层可以降低电阻和热阻;可以精确的控制GaAs和GaInP之间的化学刻蚀,便于激光器几何形状的控制。

PCI2 cells were treated under glucose deprivation as model group. Method Morphological and cytoflowmetric methods (the mitochondrial transmembrane potential; MEF method) were applied to evaluate the protective effect of SAB. The RNA levels of grp75 were measured by RT-PCR and immunocytochemistry were performed to investigate the expression level of PC12 cells under glucose deprivation and treated by SAB.

以PCl2细胞(大鼠肾上腺嗜铬细胞瘤细胞)的无糖培养建立细胞缺糖损伤模型,MTT法检测细胞的存活率;应用流式细胞仪检测亚二倍体细胞的比率及线粒体跨膜电位的改变;应用免疫细胞化学、RT-PCR法研究细胞内应激蛋白grp75的表达变化,激光共聚焦显微镜观察SAB作用下Ca(上标 2+)的变化。

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He and Nina moved to California and lived at 2005 Ivar Street, Apt.

他和Nina搬到加州,并在2005年伊瓦尔街,公寓生活。

Droperidol ( potently inhibits transfected HERGchannels and this is the probable mechanism for QT prolongation.

氟哌利多有效地抑制了转染的 HERG 钾通道,可能是 QT 间期延长的机制。

The Nazi's cruel treatment of the Jews during the Second World War is beneath contempt .

二战期间纳粹对犹太人的暴行极其可鄙。