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1.
We investigate the possibility of phantom crossing in the dark energy sector and the solution for the Hubble tension between early and late universe observations. We use robust combinations of different cosmological observations, namely the Cosmic Microwave Background (CMB), local measurement of Hubble constant (H0), Baryon Acoustic Oscillation (BAO) and SnIa for this purpose. For a combination of CMB+BAO data that is related to early universe physics, phantom crossing in the dark energy sector was confirmed at a 95% confidence level and we obtained the constraint H0=71.03.8+2.9 km/s/Mpc at a 68% confidence level, which is in perfect agreement with the local measurement by Riess et al. We show that constraints from different combinations of data are consistent with each other and all of them are consistent with phantom crossing in the dark energy sector. For the combination of all data considered, we obtained the constraint H0=70.25±0.78 km/s/Mpc at a 68% confidence level and the phantom crossing happening at the scale factor am=0.8510.031+0.048 at a 68% confidence level.  相似文献   
2.
von Neumann’s inequality in matrix theory refers to the fact that the Frobenius scalar product of two matrices is less than or equal to the scalar product of the respective singular values. Moreover, equality can only happen if the two matrices share a joint set of singular vectors, and this latter part is hard to find in the literature. We extend these facts to the separable Hilbert space setting, and provide a self-contained proof of the “latter part”.  相似文献   
3.
建立了整车8-DOF系统动力学模型,考虑了主动悬架控制,并增设了主动座椅控制,设计了车辆主动悬架系统的LQG控制器。基于Matlab仿真平台建立了整车8-DOF系统动力学仿真模型,对所得最优控制策略下的动态响应进行了仿真验证。仿真结果表明:为了改善人椅系统质心及车身质心的跳振性能需要在一定程度上弱化各轮轮胎动位移性能。从控制效能上来看,该最优控制器能够满足各行驶状态下对悬架性能的要求,改善了车辆的行驶平顺性。  相似文献   
4.
5.
In the present work we describe a two‐dimensional liquid chromatographic system (2D‐LC) with detection by mass spectrometry (MS) for the simultaneous separation of endogenous metabolites of clinical interest and excreted xenobiotics deriving from exposure to toxic compounds. The 2D‐LC system involves two orthogonal chromatographic modes, hydrophilic interaction liquid chromatography (HILIC) to separate polar endogenous metabolites and reversed‐phase (RP) chromatography to separate excreted xenobiotics of low and intermediate polarity. Additionally, the present proposal has the novelty of incorporating an on‐line sample treatment based on the use of restricted access materials (RAMs), which permits the direct injection of urine samples into the system. The work is focused on the instrumental coupling, studying all possible options and attempting to circumvent the problems of solvent incompatibility between the RAM device and the two chromatographic columns, HILIC and RP. The instrumental configuration developed, RAM‐HILIC‐RPLC‐MS/MS, allows the simultaneous assessment of urinary metabolites of clinical interest and excreted compounds derived from exposure to toxic agents with minimal sample manipulation. Thus, it may be of interest in areas such as occupational and environmental toxicology in order to explore the possible relationship between the two types of compounds. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
6.
指出了极限蕴含着理想与现实的统一,以此刻画了共产主义的实现过程——人类社会可以无限地趋近共产主义.把人类社会视为一个系统,提出了它的两条基本公理.借助于公理法,利用逻辑推理论证了劳动将逐渐成为人们的第一需要、劳动创造财富、人类的思想觉悟可以逐渐达到共产主义人生观等重要结论.  相似文献   
7.
A kinetic study of the reactions of potentially bioactive 2-amino-4-arylthiazoles with highly reactive 4,6-dinitrobenzofuroxan (DNBF) is reported herein in acetonitrile solution. The complexation reaction was followed by recording the UV–vis spectra with time at λmax = 482 nm. Electronic effects of substituents influencing the rate of reaction have been studied using structure-reactivity relationships. It is shown that the Hammett plot relative to the reaction of DNBF with 2-amino-4-(4-chlorophenyl)thiazole exhibit positive deviation from the log k1 versus σ correlation, while it showed excellent linear correlation in terms of Yukawa–Tsuno equation. It has be noticed that the nonlinear Hammett plot observed for 2-amino-4-(4-chlorophenyl) thiazole is not attributed to a change in rate-determining step but is due to nature of electronic effect of substituent caused by the resonance of stabilization of substrates. The second-order rate constant (k1) relating to the bond C–C and C-N forming step of the complexation processes of DNBF with 4-substituted-aminothiazoles and 2-amino-5-methyl-4-phenylthiazole, respectively, is fit into the linear relationship log k = sN (N + E), thereby permitting the assessment of the nucleophilicity parameter (N) of the 2-amino-4-arylthiazoles of the range (4.90 < N < 6.85). 2-amino-4-arylthiazoles is subsequently ranked by positioning its reactivity on the general nucleophilicity scale developed recently by Mayr and coworkers (2003) leading an interesting and a direct comparison over a large domain of π-, σ -, and n-nucleophiles. The global electrophilicity/nucleophilicity reactivity indexes of the 2-amino-4-arylthiazoles have been investigated by means of a density functional theory (DFT) method. .  相似文献   
8.
基于WEB的在线答疑系统的设计与实现   总被引:4,自引:0,他引:4  
梁莹 《韶关学院学报》2004,25(12):25-28
根据登录者的身份,基于WWW技术的在线答疑系统设计为三大模块:学生模块、教师模块和系统管理员模块,它们可分别完成提问、回答和版务管理等功能.还探讨了系统主要的实现技术。  相似文献   
9.
父母及家庭环境对儿童人格形成与发展具有十分重要的影响。父母要以身示范,营造和睦、健康、向上的家庭氛围。在儿童人格塑造和培养中,要十分重视智力因素的培养,特别注意早期智力与创造力的开发,重视社会适应能力的培养,包括融入集体生活的能力、人际适应能力和环境适应能力等。  相似文献   
10.
高等职业教育以能力为本位,培养面向生产、建设、管理及服务一线的高级技术型应用人才。其培养目标、培养模式应始终坚持为经济发展建设服务,依托于经济,服务于经济,服务于社会。  相似文献   
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