面向青年不同体型人群的床垫软硬度设计研究

目的本研究在对床垫软硬度进行定量化分析的基础上,探究不同体型的青年人群与床垫软硬度之间的关系。方法通过设计不同软硬度的床垫方案,测试被测试者在床垫上的压陷量,计算仰卧时脊柱形态曲线与自然脊柱形态曲线的吻合度等数据,分析体型特征与床垫软硬度的关系。结果(1)男女性的站姿脊柱形态曲线不同,男性的背部更加突出,女性则臀部更加突出;(2)床垫软硬度变化对卧姿脊柱形态中臀部的下陷影响最大,背部其次;(3)不同体型人群适合的床垫软硬度不同,被测试者的BMI值与其最佳床垫显著相关并具有统计学意义,且呈现一定的线性相关性;(4)在被测试者的BMI值相似和性别相同的情况下,站姿腰背间隙大的被测试者适合综合刚度小的床垫。结论随着体型BMI值的增加,适宜的床垫硬度逐渐增大,且同体型中,腰背间隙大的适合稍软的床垫。

High Accuracy Calculation for Excited-State Energies of H Atoms in a Magnetic Field

Using the recently developed finite-basis-set method with B splines, excited states of H atoms in a magnetic field have been calculated. Energy levels are presented for the ten excited states, 2so, 3d＇0, 3po, 3p-1, 3d_1, 4d-1, 3d-2, 4d-2, 4f-2 , and 5f-2 as a function of magnetic field strengths with a range from zero up to 2.35 × 10^6 T. The obtained results are compared with available high accuracy theoretical data reported in the literature and found to be in excellent agreement. The comparison also shows that the current method can produce energy levels with an accuracy higher than the existing high accuracy method [Phys. Rev. A 54 （1996） 287]. Here high accuracy energy levels are for the first time reported for the 3d＇0, 4d-1, 4d-2, 4f-2, and 5f-2 states.

Interferences in Photodetachment of a Negative Molecular Ion Model

By employing a two-center model, the total and differential cross sections in the photodetachment of ＂a negative molecular ion＂ are studied theoreticedly and obtained for the case of light polarization paredlel to the molecular axis. We find that in contrast to the smooth behavior of the total cross section for perpendicular polarized light, the cross section for parallel polarized light shows an interesting oscillatory structure. The oscillations in the toted cross section may provide a method to determine the distance between the two centers. We explain the oscillation in the toted cross section as an interference effect using closed-orbit theory. We also cedculated the detached-electron flux distributions on a screen placed at a large distance from the negative molecular ion. The distributions display multiple-ring-like interference patterns. Such interference patterns are similar to those in the photodetachment microscopy experiments.

Correspondence Between Oscillations and Emitted Photon Closed-Orbits in Spontaneous Emission Rate of an Atom Near a Dielectric Slab

We study the oscillations in the spontaneous emission rate of an atom near a dielectric slab. The emission rate is calculated as a function of system size using quantum electrodynamics. It exhibits multi-periodic oscillations. Four frequencies of the oscillations are extracted by Fourier transforms. They agree with actions of photon closed-orbits going away and returning to the atom. These oscillations are explained as manifestations of quantum interference effects between the emitted photon wave near the atom and the returning photon waves travelling along various closed-orbits.

Analyzing the Photodetachment Cross Section of H^(-) in Parallel Electric and Magnetic Fields

We studied the photodetachment of H^(-) in the presence of parallel electric and magnetic fields.This system is an important model that demonstrates the effects of closed-orbits and their bifurcations on the quantum spectra.Using Poisson's summation formula,we have obtained a reduction formula that represents the cross section a sum of oscillations.The reduction formula is valid uniformly.We compare it with the predication from the closed-orbit theory.

冬夏两季不同室温下温控床垫的温控效应

通过实验方法,探究冬夏季节不同室温下温控床垫铺垫层和控温层之间的温控效应。结果表明:冬季和夏季的室温环境变化对温控床垫的铺垫层和控温层的温差影响呈现线性关系;温控床垫的热传递效应要大于冷传递效应;温控床垫制冷效应热损失的主要影响因素是设置温度和室内温度的温差值,制热效应热损失的主要影响因素是室内环境温度。