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101.
构建了一个三期的入口政策与经济增长的理论模型框架,使用1995-2012年中国部分的30个省际面板数据,分别从全国、东部、中部和西部地区,建立面板模型和误差修正模型,分析出生率、受教育程度、适龄劳动参与率三个因素对经济增长的影响.结果表明:从全国来看出生率对经济增长并没有显著的影响,对于经济繁荣的东部地区出生率与经济增长表现出显著的正相关关系,中部地区出生率对经济增长并没有显著的作用,而对于相对落后西部地区出生率的增加反而会阻碍经济的增长.无论对于全国还是东、中、西三地区,受教育程度、适龄劳动参与率对经济增长均呈现出显著的正相关性,并且受教育程度从东向西对经济增长的贡献度逐渐减弱,而适龄劳动参与率从东向西对经济增长的贡献度逐渐递增.  相似文献   
102.
建立一种科学合理且可操作性强的气相分子吸收光谱仪校准方法。从仪器的工作原理及结构入手,对该类仪器提出了检出限、线性相关系数、定量重复性等性能评价参数。利用国家相关标准物质对其检出限的测量不确定度进行了评定,统一了校准方法,有力地保证了测量数据的准确性、溯源性。对计量技术机构开展该类仪器的校准工作规范的制定有一定的指导意义。  相似文献   
103.
This paper develops a one-sector overlapping generations model with endogenous labor supply and nonseparable preferences. It demonstrates that local indeterminacy arises easily under gross substitutability as soon as there exist multiple steady states. We show also that, depending on whether leisure and second-period consumption are gross substitutes, local indeterminacy holds for very different parameter configurations. If gross substitutability is satisfied, the existence of multiple equilibrium paths requires the share of capital in the total income to be strong enough with respect to the elasticity of capital-labor substitution. On the other hand, if gross substitutability is violated, local indeterminacy necessitates the share of capital in the total income to be weak enough with respect to the elasticity of capital-labor substitution. This paper is dedicated to the memory of Louis-André Gérard-Varet, Director of GREQAM from 1987 to 1999. We thank S. Catania, C. Deissenberg, J. P. Drugeon, L. A. Gérard-Varet, J. M. Grandmont, A. Kirman, T. Lloyd-Braga, P. Michel, P. Pintus,E.Thibault, B.Wigniolle, and two anonymous referees for helpful comments and suggestions. The paper benefited from comments received during a presentation at the Conference on Dynamic Equilibria, Expectations and Indeterminacies, Paris. France, 1999.  相似文献   
104.
A deep-ultraviolet (UV) microscope can output critical dimension (CD) that is consistent with an aerial image on a wafer even if the cross-sectional profile of the pattern on a photomask is varied. According to theoretical calculation, CD measured by the deep-UV microscope depends on global transmissivity, and so does the aerial image on a wafer if the cross-sectional profile is varied. The results of simulation and experiment indicate that offset between CD measured by deep-UV microscope and CD determined by the aerial image is constant despite variation of the cross-sectional profile.  相似文献   
105.
Information processing with light is ubiquitous, from communication, metrology and imaging to computing. When we consider light as a quantum mechanical object, new ways of information processing become possible. In this review I give an overview of how quantum information processing can be implemented with single photons, and what hurdles still need to be overcome to implement the various applications in practice. I will place special emphasis on the quantum mechanical properties of light that make it different from classical light, and how these properties relate to quantum information processing tasks.  相似文献   
106.
目的探讨硬膜外罗哌卡因复合芬太尼分娩镇痛对分娩方式的影响。方法回顾7136例具备顺产条件初产妇的最终分娩方式,按产妇意愿分为对照组(A组)4168例及分娩镇痛组(B组)2968例。A组产妇未接受分娩镇痛,B组产妇给予L2~3或L3~4硬膜外阻滞,头向置管后1%利多卡因5ml试验量确定阻滞平面后,予以6~15ml/h持续泵注0.15%罗哌卡因和2μg/ml芬太尼的复合液。记录汇总最终分娩方式及剖宫产原因,评定两组新生儿出生后1、5minApgar评分,评定产妇镇痛后的视觉模拟评分(VAS)及改良Bromage评分。结果B组产妇剖宫产率(20.28%)及产钳使用率(4.38%)明显高于A组(7.70%、2.33%,P<0.01);B组第一产程时间延长于A组(P<0.01);B组因第一产程延长而行剖宫产比例(64.62%)明显高于A组(42.81%,P<0.01);B组胎儿宫内窘迫的比例(12.29%)明显低于A组(31.25%,P<0.01);胎头下降停滞及羊水问题、胎位异常比例与A组比较差异均无统计学意义(均P>0.05)。两组新生儿出生后1、5min的Apgar评分差异无统计学意义(P>0.05)。B组产妇宫口6、10cm时的VAS评分明显低于A组(P<0.01),但两组产妇下肢改良Bromage评分差异无统计学意义(P>0.05)。结论0.15%罗哌卡因复合2μg/ml芬太尼的硬膜外分娩镇痛可增加产妇剖宫产率、阴道器械助产率及延长第一产程,但对新生儿Apgar评分及产妇下肢肌力无影响。  相似文献   
107.
We propose a method to generate the multi-mode entangled catalysis squeezed vacuum states (MECSVS) by embedding the cross-Kerr nonlinear medium into the Mach−Zehnder interferometer. This method realizes the exchange of quantum states between different modes based on Fredkin gate. In addition, we study the MECSVS as the probe state of multi-arm optical interferometer to realize multi-phase simultaneous estimation. The results show that the quantum Cramer−Rao bound (QCRB) of phase estimation can be improved by increasing the number of catalytic photons or decreasing the transmissivity of the optical beam splitter using for photon catalysis. In addition, we also show that even if there is photon loss, the QCRB of our photon catalysis scheme is lower than that of the ideal entangled squeezed vacuum states (ESVS), which shows that by performing the photon catalytic operation is more robust against photon loss than that without the catalytic operation. The results here can find applications in quantum metrology for multiparatmeter estimation.  相似文献   
108.
为进一步提高真空量值的复现性和准确性,最新研究采用量子技术实现对真空量值的测量与表征.该方法利用Fabry-Perot谐振腔实现腔内气体折射率的精密测量,并反演出气体密度,进而获得对应的真空量值,其中气体折射率的测量是影响真空量值准确性的关键.本文基于第一性原理,利用从头计算理论计算了在已知压力和温度条件下的氦气折射率,给出腔内气体压力与折射率关系的表达式,并利用基于Fabry-Perot激光谐振腔的真空测量装置,通过双腔谐振激光拍频精确测量了充气前后谐振激光频率的变化,测出了氦气折射率,并分析了测量不确定度.将理论计算值与实验测量值进行了对比分析,得出了制约准确度提高的主要因素,并提出了修正方法.  相似文献   
109.
X N Feng 《中国物理 B》2021,30(12):120601-120601
Multi-path (or multi-mode) entanglement has been proved to be a useful resource for sub-shot-noise sensitivity of phase estimation, which has aroused much research interest in quantum metrology recently. Various schemes of multi-path interferometers based on optical systems have been put forward. Here, we study a multi-state interferometer with multi-level atoms by projective measurements. Specifically, we investigate its ultimate sensitivity described by quantum Fisher information theory and find that the Cramer-Rao bound can be achieved. In particular, we investigate a specific scheme to improve the sensitivity of magnetometery with a three-state interferometry delivered by a single nitrogen-vacancy (NV) center of diamond with tailor pulses. The impacts of imperfections of the atomic beam-splitter, described by the three-level quantum Fourier transform, on the sensitivity of phase estimation is also discussed.  相似文献   
110.
《中国物理 B》2021,30(9):90304-090304
We investigate the advantage of coherent superposition of two different coded channels in quantum metrology. In a continuous variable system, we show that the Heisenberg limit 1/N can be beaten by the coherent superposition without the help of indefinite causal order. And in parameter estimation, we demonstrate that the strategy with the coherent superposition can perform better than the strategy with quantum SWITCH which can generate indefinite causal order. We analytically obtain the general form of estimation precision in terms of the quantum Fisher information and further prove that the nonlinear Hamiltonian can improve the estimation precision and make the measurement uncertainty scale as 1/Nm for m ≥ 2. Our results can help to construct a high-precision measurement equipment, which can be applied to the detection of coupling strength and the test of time dilation and the modification of the canonical commutation relation.  相似文献   
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