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从牛顿冷却定律入手,对固体比热容测定实验的散热修正原理进行了理论分析,并根据理论分析对传统的实验方案进行改进,不仅降低了实验操作难度,减小了误差,而且有助于学生实践创新能力的培养。  相似文献   
2.
制备了氧化铝、铈锆固溶体复合氧化物负载铂、钯的双金属催化剂Pt-Pd/ Ce0.3Zr0.7O2-Al2O3,并添加3% ZrO2助剂改性,用于柴油车尾气中CO、HC和NO的催化氧化,其中贵金属负载量仅为0.68 wt%。考察了制备过程中焙烧温度对催化剂性能的影响。催化剂活性评价结果表明,与未添加ZrO2的催化剂比较。添加ZrO2明显提高了催化剂的低温氧化活性,而且焙烧温度对催化剂的氧化性能有较大影响。焙烧温度为800 ?C时,CO和C3H6的起燃温度最低,分别为168、189 ?C,焙烧温度为700 ?C时,NO转化为NO2的转化率最高,最大转化率为36%,具有较好的热稳定性。通过XRD、N2吸附-脱附、CO化学吸附、XPS、H2-TPR等表征手段考察了催化剂物理化学性质随焙烧温度的变化情况,并分析了与催化剂活性之间的关系,得到贵金属分散度、表面化学吸附氧含量、催化剂的还原性质对氧化性能有重要影响,发挥协同作用。进而可以通过优化焙烧温度提升柴油车氧化催化剂性能,对提高工业应用柴油车尾气后处理系统的净化效率有重要意义。  相似文献   
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@@快速康复外科(fast track surgery,FTS)对传统手术围术期的治疗方法进行改进,可以减少患者的不适感、降低患者术后应激反应及并发症发生率、促进康复、缩短住院时间[1]。老年患者存在各器官功能的衰退,睡眠质量下降,常影响术后康复训练和身体功能的恢复[2]。褪黑素(melatonin)是调控机体生物节律的内分泌激素之一,主要参与人的昼夜节律和诱导睡眠的调控[3]。同时有研究发现,褪黑素亦参与了机体进食和肠道功能的调节[4]。本文拟评价人工建立褪黑素节律对老年腹腔镜直肠癌手术患者快速康复的影响。  相似文献   
4.
Zhi-Yong Ding 《中国物理 B》2022,31(6):60308-060308
The conservation law for first-order coherence and mutual correlation of a bipartite qubit state was firstly proposed by Svozilík et al., and their theories laid the foundation for the study of coherence migration under unitary transformations. In this paper, we generalize the framework of first-order coherence and mutual correlation to an arbitrary (m $\otimes$ n)-dimensional bipartite composite state by introducing an extended Bloch decomposition form of the state. We also generalize two kinds of unitary operators in high-dimensional systems, which can bring about coherence migration and help to obtain the maximum or minimum first-order coherence. Meanwhile, the coherence migration in open quantum systems is investigated. We take depolarizing channels as examples and establish that the reduced first-order coherence of the principal system over time is completely transformed into mutual correlation of the (2 $\otimes$ 4)-dimensional system-environment bipartite composite state. It is expected that our results may provide a valuable idea or method for controlling the quantum resource such as coherence and quantum correlations.  相似文献   
5.
Huan Yang 《中国物理 B》2022,31(9):90302-090302
The important applications of quantum dot system are to implement logic operations and achieve universal quantum computing based on different quantum nonlocalities. Here, we characterize the quantum steering, Bell nonlocality, and nonlocal advantage of quantum coherence (NAQC) of quantum dot system suffering nonunital and unital channels. The results reveal that quantum steering, Bell nonlocality, and NAQC can display the traits of dissipation, enhancement, and freezing. One can achieve the detections of quantum steering, Bell nonlocality, and NAQC of quantum dot system in different situations. Among these quantum nonlocalities, NAQC is the most fragile, and it is most easily influenced by different system parameters. Furthermore, considering quantum dot system coupling with amplitude damping channel and phase damping channel, these quantum nonlocalities degenerate with the enlargement of the channel parameters $t$ and $\varGamma$. Remarkably, measurement reversal can effectively control and enhance quantum steering, Bell nonlocality, and NAQC of quantum dot system suffering from decoherence, especially in the scenarios of the amplitude damping channel and strong operation strength.  相似文献   
6.
基于光栅莫尔条纹形成机理,设计并制作出波的干涉演示仪,同传统投影器-发波水槽教学演示实验仪器相比,具有机构简单,演示明显且灵活多变等优点,极大地提高课堂教学效果。  相似文献   
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