p型Ba_yFe_xCo_(4-x)Sb_(12)化合物的热电性能

以 2 价的Ba作为填充原子 ,在x=1.0— 1.6 ,y=0— 0 .6 3的组成范围内 ,系统地研究了Ba填充分数及Fe含量对p型BayFexCo4-xSb1 2 化合物电性能及热性能的影响 ,探讨了填充原子的氧化价对电性能的影响规律 ,优化了p型BayFexCo4-xSb1 2 化合物的组成和热电性能 ,对于富Co组成的Ba0 .2 7FeCo3Sb1 2 试样 ,本研究得到了 0 .9最大无量纲热电性能指数 (ZT) .     

Resonant Absorption Mechanical Spectrometer and Its Applications in Solids

An improved apparatus is developed from Ke-pendulum. This new apparatus, resonant absorption mechanical spectrometer (RAMS), can measure the internal friction of solids under a forced vibration mode and the measuring frequency can change quasi-continually from a frequency that is much lower than the resonant frequency of the pendulum system, fτ, to the one that is much higher than fτ. The internal friction measurement is able to cover the frequency range from 10^-3 Hz to kHz. The measurement method and the calculation formula of the internal friction measured by a RAMS in the full frequency range are derived. A series of resonant absorption peaks are observed in copper, alumiaium, zinc, iron samples by the RAMS. The resonant absorption characteristics of the copper sample are studied in details. The experimental results indicate that the position (frequency) of the resonant absorption peaks are independent of the resonant frequency of the pendulum system. The reality of resonant absorption mechanical spectra is discussed and an inference based on the experimental results is presented such that the RAMS is able to characterize some feature of solid materials.     

Electronic Structure and Magnetism in Sm（Co,Cu）7

The electronic density of states, spin-splittings and atomic magnetic moments of SmCo7-xCux are studied by means of the spin-polarized multi-scattering Xα method. The results show that a few of the electrons can transfer to the Sm 5d^0 orbital due to orbital hybridization between Sm and Co. The exchange interactions between 3d and 5d electrons lead to the magnetic coupling between Sm and Co, and therefore result in the long-range ferromagnetic order in SmCo7-xCux. The Curie temperature of SmCo7-xCux is generally lower than that of the corresponding pure Co, which may be explained by the weaker average strength of coupling between Co lattices due to some negative exchange couplings mainly from the 2e site. The calculated results for the Sm5Co3oCu4 cluster may lead to a better understanding of why SmCo7-xCux is stable phase. Since the negative coupling of the 2e sites becomes small and the d bond at EF becomes stronger in contrast to SmCo7, which results in decrease of the free energy of the system, the stable ferromagnetic order forms in SmCo7-xCux.     

锡偶联无规溶聚丁苯橡胶13C NMR研究(Ⅰ)烷碳区谱峰归属

研究了锡偶联溶聚丁苯橡胶烷碳区¹³C NMR谱图,借助DEPT谱区分CH和CH₂,利用文献值和经验计算公式,对实验中观察到的24个谱峰进行了归属.     

结扎家兔颈总动脉和椎动脉后额区皮质超微结构变化…

成年家兔１５只，分实验组和对照组。实验组动物结扎双侧颈总动脉和一侧椎动脉后分成Ｉ，Ⅱ，Ⅲ组，分别存活３０ｍｉｎ，１ｈ和２４ｈ。对两侧大脑半球额区皮质的相同部位进行了电镜观察。突触活性区（突触前、后膜和突触间隙）电子密度增加，分辨不清突触间隙，在Ⅱ组这种突触略多，发现极个别突触前、后膜断裂的突触；突触小泡数显著减少（ｐ〈０．００１），但三组间无显著变化（ｐ〉０．０５）；突触小泡分布多样，或聚集（Ｉ组     

极低湍流度下翼型近场尾流雷诺切应力的分布

简述了在西北工业大学低湍流度风洞中，用热线风速仪测量翼型边界层及近场尾流中速度型、湍流强度、雷诺正应力及切应力等的简况；文中着重分析了极低湍流度下（０．０２％）试验所得近场尾流中雷诺切应力的分布规律。结果表明，在尾流宽度方向及流动方向均有明显的规律性，且与常规风洞湍流度下结果相比，其有关特征值明显偏低。     

考虑接缝传荷的文克勒地基上矩形薄板的级数解

应用双重正弦级数展开的方法,推演得到了文克勒地基上计入两块矩形板间接缝传荷效应的级数解。假设接缝传递剪力与板间挠度差成正比、传递弯矩与板间转角差成正比,进而分析了单轮和单轴荷载作用在纵缝边缘中部时,接缝传荷效应对板边最大挠度和最大应力的影响规律;通过引入接缝传荷效应系数和接缝极限传荷的两个挠度比及两个应力比,建立了计入接缝传荷效应的板边最大挠度和最大应力的一般式,总结了不同板尺寸、荷载面积尺寸和类型及板材料泊松比对四个接缝影响系数和四个接缝极限传荷的挠度比及应力比的影响规律。结果表明:不同荷载面积下,受荷板接缝边缘最大挠度、最大应力均随弯矩或剪力传荷刚度系数的增大而减小,且应力的变化幅度相较挠度要小。影响系数fV^w(ξV)、fM^w(ξM)、fM^σ(ξM)与荷载圆相对半径(a/l)、相对板长(L/l)和相对板宽(B/l)无关,且单轮荷载与双轮荷载规律相同;而影响系数fV^σ(ξV)与荷载圆相对半径(a/l)有关,与相对板长(L/l)和相对板宽(B/l)无关;挠度比λV^w与荷载圆相对半径、板尺寸(L/l,B/l)及泊松比v无关,恒等于0.5,而λM^w、λV^σ、λM^σ均与荷载相对半径(a/l)、板尺寸(L/l,B/l)及泊松比v有关,且影响因素中荷载面积尺寸的影响最为显著。     

类风湿关节炎患者血清骨形态发生蛋白6和铁调素与贫血的关系

目的探讨类风湿关节炎（RA）患者骨形态发生蛋白6(BMP-6)和铁调素(Hepc)与贫血的关系。方法采用酶联免疫吸附法测定99例RA患者、19例系统性红斑狼疮（SLE）患者、40例健康志愿者的血清BMP-6、Hepc水平,同时检测RA患者的红细胞计数（RBC）、血红蛋白水平（HGB）、白细胞介素6(IL-6)、血清铁（SI）、血清可溶性转铁蛋白受体（sTfR）、铁蛋白（SF）,分析比较RA组与SLE组和健康对照组、RA患者贫血组与非贫血组、慢性病性贫血（ACD）与慢性病伴缺铁性贫血（IDA+ACD）组间及不同疾病活动度组间BMP-6、Hepc和其他贫血相关指标,以及RA患者血清BMP-6和Hepc水平与其他因素间的相关性。结果 RA患者贫血发生率为59.6%,其中ACD占52.5%, IDA+ACD占47.5%。血清BMP-6和Hepc水平在RA患者中明显升高,与SLE组、健康对照组的差异均有统计学意义（均P＜0.05）。RA贫血组的IL-6水平及类风湿关节炎疾病活动性评分（DAS28）较非贫血组均明显升高,差异有统计学意义（P＜0.05）,而两者SI、SF、BMP-6和Hepc水平的差异均无统计学意义（均P＞0.05）;RA伴ACD患者的血清SF、Hepc、BMP-6水平及DAS28评分均明显高于RA伴IDA+ACD组,差异均有统计学意义（均P＜0.05）。DAS28＞5.1的RA疾病高度活动组血清BMP-6及Hepc较DAS28评分≤5.1的疾病非高度活动组明显升高,而HGB水平明显降低,差异均有统计学意义（均P＜0.05）。RA患者的血清BMP-6与Hepc水平呈正相关（P＜0.01）,且两者均与IL-6、DAS28呈正相关（P＜0.05）,BMP-6还与SI呈正相关（P＜0.05）。结论 RA患者贫血类型以ACD为主,其血清BMP-6和Hepc水平均明显升高,在伴ACD或疾病高度活动的RA患者中升高尤其明显,且互相关系密切,说明BMP-6和Hepc水平异常正是诱导RA患者发生ACD的主要因素之一,两者可能可以作为RA患者ACD治疗的靶点,其在RA中的作用机制值得进一步研究探索。     

Large-aperture collimated wavefront evaluation based on sparse subaperture北大核心CSCD

A wavefront evaluation method based on sparse subaperture was proposed for the collimated wavefront of 300 mm aperture wavelength-tuned interferometer. The method used the wavefront data of sparse aperture to construct a uniform and equally spaced subaperture arrangement model and utilized the simultaneous fitting algorithm to realize the reconstruction of the full-aperture collimated wavefront. The change rules of subaperture spacing and subaperture size on the reconstruction accuracy were analyzed by the numerical calculation, and the optimized subaperture arrangement way was obtained. Finally, an optimized subaperture arrangement with a subaperture size of 10.8 mm and an adjacent subaperture center spacing of 9.72 mm was used for the sparse subaperture evaluation of 300 mm aperture collimated wavefront. The simulation results show that the optimized sparse subaperture evaluation wavefront residual peak valley (PV) value is 0.001 6λ and the residual root mean square (RMS) value is 1.689 3e−4 λ. Copyright ©2022 Journal of Applied Optics. All rights reserved.     

合作学习的优势与价值刍议

 合作学习是20世纪70年代初兴于美国,并在70年代中期至80年代中期取得了实质性进展的一种教学理论与策略体系。由于运用的广泛性和教育教学成效的显著性,合作学习被誉为“近几十年来最成功和最重要的教学改革”。当前合作学习已成为一种大家普遍关注和倡导的教学理论和策略体系,被公认为是一种较为有效的教学模式。合作学习模式与传统教学模式的比较在西方传统的教学模式下,教学活动被认为是:教师是知识的拥有者,把知识转移给学生,学生是类似容器的被动知识接受者;教师按分数将学生分等级或按是否获得好的工作分类;教学中不考虑师生间、学生间的人际关系;保持一种竞争的组织结构,学生为超过同伴成绩而学,教师为胜过同事而教;。