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1.
出租车驾驶员的振动舒适性不仅影响驾驶员的健康,而且影响行车安全.在对重庆市出租车驾驶员的振动舒适性分别进行等速试验和跟踪监测基础上,分析了试验结果,发现出租车等速工况下的振动舒适性试验评价结果不能代表实际工况下的振动舒适性情况.最后结合ISO2631舒适性评价标准对重庆市出租汽车驾驶员的振动舒适性进行了客观评价.  相似文献   

2.
脉冲时滞微分方程组振动性及渐近性   总被引:3,自引:1,他引:2  
研究了一阶三维线性脉冲时滞微分方程组的振动性与渐近性,引入了弱振动的概念,给出引理解决了非振动解各分量间的符号关系,由此得到了若干振动性与渐近性的判别准则,并举例说明了准则的有效性.  相似文献   

3.
二阶非线性泛函微分方程解的振动准则   总被引:7,自引:0,他引:7  
利用振动性理论研究了二阶非线性泛函微分方程解的振动性与渐近性,并获得了一些新的振动准则.这些准则推广和验证了大量的现存结果,而且处理了已知振动准则所不能应用的情形.  相似文献   

4.
研究了一类具有变系数二阶中立型微分方程的非振动性和振动性.讨论了方程的非振动解的渐近性.给出了方程的所有解振动的充分条件.所得结论推广了已知的一些结果.  相似文献   

5.
研究了一类非线性脉冲时滞微分方程的振动性.证明了在一定条件下,可以由线性脉冲时滞微分方程的振动性判定非线性脉冲时滞微分方程的振动性.得到了非线性脉冲时滞微分方程与相应的线性脉冲时滞微分方程振动性等价的条件,并给出了它的应用。  相似文献   

6.
研究非振动线性二阶常微分方程的线性扰动方程的振动性与非振动性,主要方法是引入一些新的 Riccati 变换.  相似文献   

7.
研究二阶线性中立型微分方程的振动性,对具有多时滞的一类二阶中立型微分方程的振动性进行讨论,利用比较原理将二阶多时滞中立型微分方程的振动性判断转化为判断一阶方程的振动性,这种比较原则最大限度地使研究的二阶方程得到简化.  相似文献   

8.
脉冲时滞向量双曲型方程解的振动性   总被引:1,自引:1,他引:0  
研究一类具脉冲时滞的双曲型向量泛函微分方程解的振动性.方法是采用由Domslak引进的H-振动性的概念,将向量微分方程解的振动问题转化为标量微分不等式正解和负解的不存在性问题,得到了若干解的H-振动性的判别准则.  相似文献   

9.
采用传感器对振动成型基层材料的塑性变形、振动加速度和压实力进行了采集.通过振动三参数对振动压实工艺输出能量的分析,定义了评价振动压实工艺压实能力的评价参数——激振强度;通过对基层材料振动压实塑性变形曲线的分析,定义了被压材料可压实性评价参数——可压实性系数;对典型道路材料的可压实性进行了对比研究.结果表明,在压实效果的影响上,当激振强度大于3.5时,振动压实工艺才具有较强的压实能力;材料的振动压实塑性变形与振动时间呈对数关系,在振动压实50 s后,塑性变形处于稳定状态;在材料可压实性方面,沥青混合料的可压实性最差,二灰结合料可压实性最好,基层材料的可压实性基本处于同一水平.研究结果还表明,用振动压实工艺单位时间内输出的能量和道路材料产生单位塑性变形所需的压实应力,来评价振动工艺的压实能力与被压材料可压实性是合理的.  相似文献   

10.
汽车平顺性客观评价方法   总被引:4,自引:0,他引:4  
现行国标GB4970-1996《汽车平顺性随机输入行驶试验方法》与国际上通行的振动评价方法有一定差异,而且国内对汽车平顺性的特点研究不够深入。分析了国际上的几种振动评价方法。进行汽车平顺性道路试验,测量驾驶员坐垫处、靠背处、脚以及坐垫转动等10个轴向的振动,以期全面分析汽车平顺性的特点,进而提出合理的客观评价方法。试验表明座椅垂向振动加权系数wk和wb对振动评价指标影响很小;利用时域法分析得振动的峰值因子在4~8之间;分析了各轴向振动所占的比重,发现坐垫垂向振动、靠背前后振动和坐垫俯仰角振动对振动舒适性影响较大。试验分析表明现行汽车平顺性国家标准对汽车中人体所承受的振动约低估了3dB。结合试验结果,提出了一种简便有效的测量方法。  相似文献   

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.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
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   

15.
何延凌 《科技信息》2008,(4):258-258
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   

16.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

17.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

18.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

19.
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   

20.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

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