Why Flat Space Cosmology Is Superior to Standard Inflationary Cosmology

Following recent Cosmic Microwave Background (CMB) observations of global spatial flatness, only two types of viable cosmological models remain: inflationary models which almost instantaneously attain cosmic flatness following the Big Bang;and non-inflationary models which are spatially flat from inception. Flat Space Cosmology (FSC) is the latter type of cosmological model by virtue of assumptions corresponding to the Hawking-Penrose conjecture that a universe expanding from a singularity could be modeled like a time-reversed black hole. Since current inflationary models have been criticized for their lack of falsifiability, the numerous falsifiable predictions and key features of the FSC model are herein contrasted with standard inflationary cosmology. For the reasons given, the FSC model is shown to be superior to standard cosmology in the following eleven categories: Predictions Pertaining to Primordial Gravity Waves;Cosmic Dawn Early Surprises;Predicting the Magnitude of CMB Temperature Anisotropy;Predicting the Value of Equation of State Term w;Predicting the Hubble Parameter Value;Quantifiable Entropy and the Entropic Arrow of Time;Clues to the Nature of Gravity, Dark Energy and Dark Matter;The Cosmological Constant Problem;Quantum Cosmology;Dark Matter and Dark Energy Quantitation;Requirements for New Physics.

橡胶胶囊硫化模具的结构设计

以硬质铝合金2A14-T6作原材料设计并制做了橡胶胶囊充气式硫化模具;使用电脑软件ANSYS-Workbench建立了硫化模具热力耦合模型,分析了力学强度、模具厚度和热膨胀变形量并利用相关理论校验了分析结果。结果表明,设计的三个半硫化模具有力保证了橡胶胶囊硫化成型过程中尺寸和厚度稳定;力学强度、模具厚度和热膨胀变形量校验结果符合技术要求;橡胶胶囊硫化模具满足用户使用要求。

Pseudo-beam method for compressive buckling characteristics analysis of space inflatable load-carrying structures

This paper extends Le van＇s work to the case of nonlinear problem and the complicated configuration. The wrinkling stress distribution and the pressure effects are also included in our analysis. Pseudo-beam method is presented based on the inflatable beam theory to model the inflatable structures as a set of inflatable beam elements with a prestressed state. In this method, the discretized nonlinear equations are given based upon the virtual work principle with a 3-node Timoshenko＇s beam model. Finite element simulation is performed by using a 3-node BEAM189 element incorporating ANSYS nonlinear program. The pressure effect is equivalent included in our method by modifying beam element cross-section parameters related to pressure. A benchmark example, the bending case of an inflatable cantilever beam, is performed to verify the accuracy of our proposed method. The comparisons reveal that the numerical results obtained with our method are close to open published analytical and membrane finite element results. The method is then used to evaluate the whole buckling and the loadcarrying characteristics of an inflatable support frame subjected to a compression force. The wrinkling stress and region characteristics are also shown in the end. This method gives better convergence characteristics, and requires much less computation time. It is very effective to deal with the whole load-carrying ability analytical problems for large scale inflatable structures with complex configuration.

Deformation of wrinkled membrane inflatable structures under concentrated loads

The axisymmetric deformation of a paraboloidal membrane inflatable structure subjected to a concentrated load at its apex and a uniform internal pressure was analyzed. The wrinkle angle was obtained according to the membrane theory when wrinkles appeared and determined the wrinkle region. The wrinkled deformation was obtained based on the relaxed energy function. The effects of inflation pressure and concentrated loads on the wrinkle angle were analyzed and the deformation was obtained at the apex of structure. According to the numerical analysis, the shape of deformed meridians with wrinkles was obtained.

Dirac-Born-Infeld-Einstein Theory with Weyl Invariance

Weyl invariant gravity has been investigated as the fundamental theory of the vector inflation. Accordingly, we consider a Weyl invariant extension of Dirac-Born-Infeld type gravity. We find that an appropriate choice of the metric removes the scalar degree of freedom which is at the first sight required by the local scale invariance of the action, and then a vector field acquires mass. Then non-minimal couplings of the vector field and curvatures are induced. We find that the Dirac-Born-Infeld type gravity is a suitable theory to the vector inflation scenario.

The Reversible Cyclic Universe in the Reversible Multiverse and the Reversible String Theory

The paper posits that the multiverse is reversible, so all universes in the multiverse are reversible cyclic universes which have the inexhaustible resources of space-time to expand. The collision of expanding universes is permanently irreversible, forbidden in the reversible multiverse, so every universe is surrounded by the zero-energy interuniversal void as the permanent gap among universes to keep universes apart. A zero-sum energy dual universe of positive energy universe and negative energy universe can be created in the interuniversal void, and the new dual universe is again surrounded by the interuniversal void. This paper also posits the reversible string theory with oscillating space-time dimension number oscillating between 11D (space-time dimension) and 4D without the conventional compactization of string. Dimension number decreases with decreasing speed of light, decreasing vacuum energy, and increasing rest mass. The 4D and the 11D have zero and the highest vacuum energies, respectively. The universes in the reversible multiverse oscillate reversibly between high and low dimension numbers. Under symmetry breaking as in our universe, the positive energy universe as our observed universe absorbed the interuniversal void, while the negative energy universe did not. The interuniversal void has zero vacuum energy, so the absorption of the interuniversal void by the positive energy universe forced the positive energy 10D universe with high vacuum energy to be transformed into the positive energy 4D universe with zero vacuum energy, resulting in the inflation followed by the Big Bang. The negative energy universe undergoes dimension number oscillation between 4D and 10D dimension by dimension. The negative energy >4D universe is hidden, and the negative energy 4D universe appears as dark energy. The calculated percentages of dark energy, dark matter, and baryonic matter and the calculated time for dark energy to start are in good agreements with the observed values.

String Theory with Oscillating Space-Time Dimension Number

In conventional string theory with fixed space-time dimension number, the extra space dimensions are compactized. In string theory with oscillating space-time dimension number, dimension number oscillates between 11D and 10D and between 10D and 4D reversibly, and there is no compactization. Dimension number decreases with decreasing speed of light and increasing rest mass. The 4D particle has the lowest speed of light and the highest rest mass. The two different oscillations between 10D and 4D are the stepwise oscillation passing through every dimension number and the direct oscillation oscillating directly between 10D and 4D without the intermediate dimension numbers. Dark energy represents the stepwise oscillation, and dark energy becomes observable only when it has 4D space-time. 4D baryonic matter and 4D dark matter represent the direct oscillation directly from 10D to 4D. Our universe is the dual cyclic universe of the dark energy universe and the baryonic-dark matter universe. The Big Bang in the baryonicdark matter universe produced irreversible kinetic energy that stopped the reversible direct oscillation. The reversible direct oscillation will resume after the Big Crush to remove irreversible kinetic energy. Our cyclic universe started from the zero-energy universe through the four-stage transformation. The theoretical calculated percentages of dark energy, dark matter, and baryonic matter are 68.3, 26.4, and 5.3, respectively, in agreement with observed 68.3, 26.8, and 4.9, respectively. According to the calculation, dark energy started in 4.28 billion years ago in agreement with the observed 4.71 ± 0.98 billion years ago.

超大型组合翼伞开伞性能研究

为深入了解超大型组合翼伞与连续翼伞开伞过程的差异,文章通过数值模拟计算对超大型组合翼伞和连续翼伞的开伞性能进行了对比研究。首先,基于自由曲面变形(Free-Form-Deformation,FFD)理论建立了超大型翼伞的展向折叠模型,然后应用任意拉格朗日-欧拉(ArbitraryLagrange-Euler,ALE)方法对翼伞折叠模型进行了充气过程的流固耦合仿真计算。分析了超大型组合翼伞和连续翼伞充气过程中的伞衣外形、伞衣应力和气室充气规律,深入对比了超大型组合翼伞和连续翼伞的充满时间和开伞动载。研究表明,连续翼伞和组合翼伞的开伞性能差异很小,两者的充满时间相差不大,组合翼伞展开效果更好,动载之差在5%左右。与连续翼伞相比,组合翼伞更易于制造和使用。研究将为超大型翼伞的设计优化提供一定的参考。

充气膨胀控制型锚杆的承载性能研究

为深入、系统地研究充气膨胀控制型锚杆的承载性能,考虑充气压力、挤土管片厚度及挤土管片外表面粗糙度的影响,制作了5组充气膨胀控制型锚杆和3组传统注浆锚杆,在相同的地质土层中进行了锚杆拉拔试验。依据试验加载现象和试验数据对这5组充气膨胀控制型锚杆的承载性能进行了深入、系统的分析,通过绘制荷载-位移曲线对比分析了不同试验组充气锚杆的承载能力。结果表明,充气压力、挤土管片厚度及挤土管片外表面粗糙度的增加均可提高充气膨胀控制型锚杆的承载性能。对比传统注浆锚杆,充气膨胀控制型锚杆的承载能力和抵抗变形能力更强,具有重要的工程应用价值。进一步基于圆孔扩张理论推导出充气膨胀控制型锚杆的承载力计算理论公式,极限承载力理论值与试验值较为符合,为该型号锚杆的工程设计及运用提供了理论依据。

空间薄膜反射镜的研究发展现状

空间薄膜反射镜由于具有面密度低,易于折叠展开且成本低等优点很好地满足了空间反射镜的超轻量、超大口径的要求,因此在空间科学研究领域倍受关注。介绍了空间薄膜反射镜的发展,包括薄膜反射镜的理论基础,充气式薄膜反射镜和静电拉伸薄膜反射镜及其他类型的反射镜的代表成果。而后对空间薄膜反射镜的技术难点进行了分析;重点讨论了薄膜反射镜用聚酰亚胺薄膜的生产情况以及薄膜反射镜的面形控制、面形检测和反射镜支撑结构的设计。最后总结了反射镜近期的研制情况、存在的问题和应用发展趋势。认为空间薄膜反射镜作为国内外空间科学的热点,在未来的几十年内将在航天领域的太空望远镜、空间侦察相机、人造太阳、微波天线等方面得到广泛应用。

矩形薄膜和充气管的屈曲及后屈曲行为分析

对矩形薄膜及充气管的屈曲及后屈曲过程进行了分析。首先基于矩形薄膜褶皱区域的应力平衡关系,得到了矩形剪切薄膜褶皱的波长及幅度的表达式,并考虑了微小的初始张力的作用。基于稳定性理论建立了薄膜褶皱的数值分析方法,通过实验的方法对分析结果进行了验证。分析表明矩形剪切薄膜的屈曲过程是分枝点平衡问题。对于充气管的分析是基于张力场理论建立了其扭转临界扭矩的表达式,并与数值分析的结果进行了对比分析,分析表明充气管的屈曲过程是极值点平衡问题。通过对比分析,两种结构形式的分析结果与数值分析的结果基本符合。建立的分析方法能够有效地进行薄膜结构的屈曲及后屈曲过程的分析。

基本载荷作用下橡胶类材料的超弹性力学性能分析

基于有限变形的基本理论,对基本载荷作用下橡胶类材料的超弹性力学性能进行了分析.在高玉臣所提出的橡胶类材料的本构模型的基础上,给出了1种新的不可压缩超弹性应变能函数.引入参数α,当n=1且α=1时,新模型转化为Mooney-Rivlin模型,而当n=1且α=0时,新模型转化为Neo-Hookean模型.利用新的本构关系对橡胶类材料在单轴拉伸以及受内压膨胀2种基本载荷作用下的超弹性力学性能进行了研究,分析了本构参数对单轴拉伸和内压膨胀的影响,指出本构参数n为材料的强化参数,橡胶圆管受内压膨胀时存在失稳现象,其稳定性不仅依赖于本构参数n而且与本构参数α相关.

货币供给与通货膨胀背离的时变成因分析

本文以现实经济对弗里德曼货币数量论失效的印证为基础,从货币需求结构和产出缺口视角建立时变参数菲利普斯理论分析框架,探讨在实体部门与虚拟部门货币流通渠道内,产出缺口为正或负的条件下,货币供给与通胀背离的内在机理。并选取2015年1月至2020年6月的金融数据,分析不同时变参数下产出缺口、生产者价格指数、预期、货币政策与经济不确定因素对通胀的同期时变效应,具体刻画不同因素对通货膨胀同期影响效应的持久性突变与渐进性演变特征。研究发现:流向实体部门的货币量对通胀影响程度不到虚拟部门的8.6%,虚拟经济与实体经济货币结构性失衡将降低通胀对实体经济货币供给的响应系数,加剧货币供给与通胀的背离;与价格型货币政策对通胀的影响程度0.15相比,数量型货币政策影响程度为0.25,以数量型货币政策为基础适当采用价格型货币政策更加能够实现既定经济目标;通胀预期对通胀影响无论在当期还是在中长期都具有持久惯性特征,说明当前消费者对政府政策信心度较高,可以将前瞻性指引作为未来货币政策选择。

人民币汇率与通货膨胀的关系问题思考

2006年国内两大经济现象:物价上涨和人民币汇率的升值成为国内许多学者谈论的主要话题。本文从不同角度来说明这两种现象发生的原因及其关系。对于这种货币对内贬值而对外升值的特殊情况已不能单纯的用传统的“购买力平价理论”来解释了。另外,我国的通货膨胀属于结构性通货膨胀,也不能简单地和汇率问题联系在一起。只有对内疏导通货膨胀压力,削弱长期贬值倾向,对外平衡贸易收支,化解短期升值压力,才能改善人民币现在这种进退两难的困境。

通胀风险下基于HARA效用的DC型养老金计划

通货膨胀是养老基金管理过程中最直接最重要的影响因素之一.假设通胀风险由服从几何布朗运动的物价指数来度量,且瞬时期望通货膨胀率由Ornstein-Uhlenbeck过程来驱动.金融市场由n+1种可连续交易的风险资产所构成,养老基金管理者期望研究和解决通胀风险环境下DC型养老基金在累积阶段的最优投资策略问题,以最大化终端真实财富过程的期望效用.双曲绝对风险厌恶(HARA)效用函数具有一般的效用框架,包含幂效用、指数效用和对数效用作为特例.假设投资者对风险的偏好程度满足HARA效用,运用随机最优控制理论和Legendre变换方法得到了最优投资策略的显式表达式.

薄膜充气梁有限元分析方法与结构特性研究

文章采用3种数值计算模型对薄膜充气梁进行分析研究。首先基于铁木辛柯梁线弹性分析理论,考虑充气压力效应,推导薄膜充气梁非对称单元刚度矩阵,采用稀疏矩阵存储,应用共轭梯度法求解有限元平衡方程,并用VC编程实现;然后提出了分别采用壳单元和预应力薄膜单元的非线性有限元分析模型,并给出了基于ANSYS的数值分析过程与方法;通过对薄膜充气梁的参数特征分析,考察了3种计算模型的适用性,分析结果揭示了薄膜充气梁复杂的结构行为特性。

扇与Halin图的一致膨胀图的关联色数

设图G的点集V(G)={v1,v2,…,vn},G的膨胀图FG的点集V(FG)=V1∪V2∪…∪Vn,且对x∈Vi,y∈Vj,有xy∈E(FG),当且仅当i=j或vivj∈E(G)。若对所有的i,满足Vi=t,则称其为G的一致膨胀图。给出了扇与Δ≥6的Halin图的一致膨胀图的关联色数,它们均为该膨胀图的最大度加1。

考虑气压效应平流层平台柔性飞艇变形分析方法与特征研究

为研究气压对平流层飞艇变形性能的影响,基于铁木辛柯梁分析理论,将低阻尼流线形飞艇假设为分段等截面充气梁,采用叠加法推导了考虑气压效应的柔性飞艇总体挠度计算式。同时,将柔性飞艇作为预应力薄膜结构,应用ANSYS软件,采用小杨氏模量法进行充气预应力找形,并基于找形结果进行载荷下非线性变形分析。在此基础上计算了飞艇外气囊在不同头部荷载与气压下的总体挠度并比较了两种方法的计算值,发现两者变化趋势一致。最后,建立了25 m验证飞艇的计算模型,得到了控制点应力和总体变形;给出了飞艇下腹线在不同气压下的位形,将其与测量值进行比较表明:计算值和测量值基本相等,误差小于5%。本文对大型柔性飞艇设计分析具有一定的参考价值。

充气展开自支撑臂振动模态分析

充气展开自支撑臂是由层合铝膜和离散自支撑壳组成,可在无充气压力下实现对有效载荷的支撑。为提高充气展开自支撑臂振动特性预测精度,首先,基于Timoshenko梁理论和哈密顿原理,推导了自支撑臂振动微分方程,提出了考虑充气压力的预应力和构型变化的梁单元模型。该单元模型考虑了结构自支撑壳的离散分布特性,使建立的质量矩阵更接近自支撑臂结构的真实值。然后,通过实验对该模型进行验证,结果表明本文方法比传统梁单元模型具有更好的精度。最后,分析了充气压力和自支撑壳宽度等参数对自支撑臂结构振动模态的影响规律,结果可为充气展开自支撑臂的设计提供理论参考。