Experimental versus theoretical robustness of rotating solutions in a parametrically excited pendulum: A dynamical integrity perspective

The objective of this paper is showing how global safety arguments can be fruitfully used to interpret experimental results of a pendulum parametrically excited by wave motion. In fact, the results of an experimental campaign developed with the aim of simulating sea-waves energy production by a parametric pendulum show that rotations exist in a region which is smaller than the theoretical one. This discrepancy can be partially attributed to the experimental approximations and constraints, but it has a deeper theoretical motivation. By comparing the experimental results with the dynamical integrity profiles we have found that experimental rotations exist only where a measure of dynamical integrity accounting for both attractor robustness and basin compactness is large enough, so that they can support experimental imperfections leading to changes in initial conditions.     

A transfer efficiency model for ultrasound mediated drug/gene transferring into cells

Ultrasound is a very promising technology to mediated drug/gene transferring into cells. However the relations between cell experimental conditions and results have been still unknown. It seriously impeded the development of the technology. In the article, a transfer efficiency model for ultrasound mediated drug/gene transferring into cells in stable cavitation was constructed. To testify the model, the numerical results were compared with the cell experimental data from six literatures in the entirely different experimental conditions. The numerical results fit the cell experimental data well. Despite simplifications and limitations, the model for the first time established the relationship between the cell experimental results about transfer efficiency and the conditions including ultrasound, microbubble and cells in stable cavitation.     

Study on the Performance of the nonlinear Joint Transform Correlator

l.IntroductionJointtransformcorrelation[1]hasbeeninvestigatedwidelyinrecentyears[2~4]be-causeitsreferenceimagesandobjectimagescanbeuPdatedinreal-time[5J.Nonlinearjointtransformcorre1ationtheoretica1ana1ysis[']showsthatcomparedwiththelinearjointtransformcorrelation,non1inearjointtransformcorrelationcanproducemorehighautcacorre1ationPeakintensity,andthelargerPeaktosideloberatiothataregoodforelectronicdevicestodetectandana]yze.Onthebasisofthemodu1ationprincipleana1ysisoftheliq-uidcrysta11ightva…     

1—50ev能区e—He散射总截面的绝对测量

文章详细地介绍了一台快脉冲电子飞行时间谱仪，在谱仪上测量了１—５０ｅＶ能区的ｅ—Ｈｅ散射绝对总截面（ＴＣＳ），测量的精度优于５％，与其它的实验结果和理论计算值比较，在误差范围内符合得较好，文章也介绍了实验方法和误差分析。 关键词：     

400~1500 MeV质子轰击铅靶和钨靶的出射中子能谱的FLUKA和Geant4模拟研究

在ADS散裂靶系统的优化设计中,蒙特卡罗方法结合可靠的散裂反应理论模型进行中子学计算具有重要的作用。本工作利用Geant4程序中的INCLXX模型、BIC模型以及BERT模型和FLUKA程序分别模拟了597 MeV和1 500 MeV质子轰击薄铅靶不同出射角度的中子双微分截面,500,1 500 MeV质子轰击厚铅靶不同出射角度的中子双微分产额,以及400,600,800,1 000和1 200 MeV质子轰击厚钨靶在反角方向（175 °）的中子双微分产额,并与实验数据进行比较。研究表明,对于薄铅靶,Geant4程序的INCLXX模型和FLUKA程序模拟结果与实验符合得更好。能量在10～40 MeV范围内,BIC模型模拟结果明显高于实验数据,而BERT模型模拟结果略微低于实验数据。对于厚铅靶,在40 MeV左右所有的模拟结果都低于实验数据。对于厚钨靶,Geant4程序的BIC模型和FLUKA程序与实验数据符合得较好,INCLXX模型在能量高于60 MeV时模拟结果低于实验数据,BERT模型与实验数据差异较大。总体来看,Geant4程序的INCLXX模型和FLUKA程序进行ADS散裂靶相关的中子学的计算是合理和可靠的。The reliable Monte Carlo simulation codes coupled with nuclear reaction models play an important role in the neutronic calculation for the design and optimization of the ADS spallation target. In this work, the double differential cross sections at different angles produced from a thin lead target bombarded with 597 and 1 500 MeV protons, the neutron energy spectra at different angles produced from a thick lead target bombarded with 500 and 1 500 MeV protons, and the neutron energy spectra in the backward direction(175°) produced from a thick tungsten target bombarded with 400, 600, 800, 1 000 and 1 200 MeV protons are calculated with the Geant4 code coupled INCLXX, BIC and BERT models and the FLUKA code. The calculations are compared with the available experimental data. The results show that, for the thin lead target, the calculations with the Geant4 coupled INCLXX model and FLUKA code well reproduce the experimental results. In a energy range from 10 to 40 MeV, BIC model obviously overestimates the experimental results, and BERT model slightly underestimates the experimental results. For the thick lead target, all of the calculations underestimate the experimental results around 40MeV. For the thick tungsten target, the Geant4 coupled BIC model and FLUKA code well reproduce the experimental results. INCLXX model underestimates the experimental results above 60 MeV. BERT model bad reproduces the experimental results. Overall, the neutronic calculations with the Geant4 code coupled INCLXX model and FLUKA code for the ADS spallation target is reasonable and reliable.     

A quantum mechanical study of the He,H-, He-He and He-H systems

This paper applies the methods for treating diatomic molecules described in papers I and II of this series, to the interation of two normal helium atoms and the interaction of a normal helium atom and a hydrogen atom. The results are compared to the experimental results of Amdur and referred to other theoretical results where they exist. The results on the He-H interaction are in fair agreement with Amdur's experimental work. The repulsive potential of two normal helium atoms disagrees with Amdur's experimental results at the distances between 1 and 2 angstroms. The helium atom and negative hydrogen ion are also discussed.     

Hydrogen Balmer-alpha broadening in dense plasmas

This work presents a theoretical analysis of experimental results for the hydrogen Balmer-alpha line in dense plasmas, with electron densities between 2x10(18) and 9x10(18) e/cm(3) A simulation of both electrons and ions is employed to produce reliable theoretical widths. These results are essentially in agreement with standard theory results and, for the most part, disagree with the experimental results. Consequently, either mechanisms not accounted for in the theoretical results (such as quadrupoles) are more important than previously thought at these densities, or else there is a problem in the experimental data (such as a possible reabsorption, which is not ruled out by the experimental data).     

光电效应伏安特性实验改进研究

光电效应实验及理论解释,为量子理论的建立奠定了基础,在光电效应伏安特性实验中,如何有效减少实验影响因素,提高测量结果的精确度,成为光电效应伏安特性实验改进的一个关键点。本从光电效应实验测量的伏安曲线出发,分析理论与实验结果上的差异,提出了影响实验结果的因素以及相应的实验操作办法,为光电效应伏安特性实验的改进,获得更加精确的实验数据以及光电效应实验的应用奠定了基础。     

基于DISLab平抛运动实验的改进

利用＂数字信息系统实验室＂（DISLab）对物体的平抛运动进行了实验研究,并针对实验装置中存在问题提出了改进方案,最后将改进后的实验装置与原实验装置的实验结果进行比较研究,结果表明改进后的实验装置明显地提高了测量精度。     

样品厚度对稳态法测定不良导体导热系数实验的影响

用稳态法测量了不同厚度橡胶板的导热系数,并分析了实验结果的一致性和正确性.发现当样品厚度较小时测量结果具有更优的一致性,并且更接近于真实值.     

Quantitative comparison between theoretical predictions and experimental results for the BCS-BEC crossover

Theoretical predictions for the Bardeen-Cooper-Schrieffer-Bose-Einstein condensation crossover of trapped Fermi atoms are compared with recent experimental results for the density profiles of 6Li. The calculations rest on a single theoretical approach that includes pairing fluctuations beyond mean-field. Excellent agreement with experimental results is obtained. Theoretical predictions for the zero-temperature chemical potential and gap at the unitarity limit are also found to compare extremely well with Quantum Monte Carlo simulations and with recent experimental results.     

Luminescence problems

The article deals with the interpretation of the experimental results on luminescence and on the degree to which this interpretation is unambiguous and noncontradictory. More than 30 concrete cases are considered and are used as examples to demonstrate that if the experimental conditions that are seemingly of secondary importance are not sufficiently well accounted for the experimental results themselves may turn out to be ambiguous. The particular experimental conditions that can be especially “insidious” in this respect are indicated. The examples concern the kinetics of the luminescence and the investigations of its spectra and polarization.     

冲击压缩下NaCl单晶光辐射特性的研究

 用光辐射技术研究了氯化钠单晶冲击压缩下的光辐射特性,得到了在45～70 GPa压力范围内NaCl单晶的光谱吸收系数随冲击压力的变化,把这一结果与Kormer等人的结果比较,发现在较低压力下与Kormer等人的结果相差较少,当压力较高时实验结果比Kormer等人的结果约大1个数量级。并用实验结果计算了电子迁移率随冲击温度的变化,得到的结果与Ziman理论基本一致,从而解决了一直来Kormer的实验结果与Ziman理论不一致的困难,进一步证明了Ziman理论的正确性。     

抗爆容器内爆炸流场数值模拟

 采用计算流体动力学中的二阶精度TVD差分格式和特殊算子分裂法,按轴对称问题,对半球顶圆柱筒密闭式抗爆容器内部爆炸流场进行了数值模拟。计算得到的容器壁面载荷分布与实验结果基本一致。不同时刻爆炸流场压力分布图像清晰地描述了容器壁面的冲击波加载过程。     

A time-dependent ASE calculation for transient gain enhancement. of picosecond pulses in a large-aperture KrF laser amplifier

In a large-aperture KrF laser amplifier, steady-state gain is heavily reduced by intra-cavity amplified spontaneous emission (ASE). However, the reduced gain can be transiently enhanced by temporally suppressing the ASE with an intense depleting short pulse. Previously, we reported the experimental observation of this transient gain enhancement and numerical calculations to explain the experimental results. However, a discrepancy was noticed between the experimental results and the calculated values, which was due to the neglect of the propagation time of laterally traveling ASE. In this paper, we present a novel time-dependent ASE code incorporating the lateral-ASE transit time and report the calculation results using the developed ASE code. The calculated values agreed with the experimental results. Received: 8 March 2000 / Published online: 5 April 2000     

水位骤变时的饱和-不饱和渗流数值计算

本文应用全隐式交替方向迭代法对水位骤变时的饱和-不饱和渗流问题求出了数值解。对于赤井模型,计算结果与实验结果十分接近,比有限元法的计算结果好。对于大尺度的驹田蓄水池模型,计算结果与有限元法的结果基本一致。     

移动通信GSM900系统用高温超导滤波器设计与测试

本研究设计了应用于移动通信中使用最广泛的GSM900系统的12节高温超导微带滤波器。由于采用新型谐振器结构，该滤波器具有结构紧凑、带边陡峭的优点。滤波器的中心频率为902．5MHz，带宽25MHz。在50K的测试温度下实验结果与设计结果较好地符合，通带内插入损耗小于0．25dB。基于测试结果，本还详细讨论了基片的介电常数和测试温度对滤波器中心频率的影响。     

Analysis of volumetric unfrozen water contents in freezing soils

In this study, a series of freezing experiments were carried out to investigate the changes of volumetric unfrozen water contents in freezing soils. The experimental results show that the soil type and the initial volumetric water content have significant effect on the freezing point and volumetric unfrozen water content of freezing soils. On the base of the experimental results and the previous researches, a new model was developed to describe the changes of the volumetric unfrozen water contents in freezing soils. The developed model was validated by comparing the calculated results against the experimental ones.     

X光加热金平面靶再发射时间的数值模拟

 用一维多群辐射输运程序对X光加热金平面靶的物理过程进行了数值模拟, 计算出了X光再发射延迟时间, 与最近的双盘靶测得的再发射延迟时间的实验结果相当吻合。在各种因素的影响下, X光各能区再发射的延迟时间的变化趋势与实验结果一致的。这说明这个一维多辐射输运程序可以较好的模拟X光打击平面靶的实验结果。     

密闭实验大厅内散射中子注量的模拟研究

为能够快速评判实验测试方案和预估实验结果,建立了中子体通量的快速估算模型。理论上,封闭空间中子平均体通量与特征长度的平方成反比,且中子体通量的大小能反映散射中子注量强弱。采用蒙特卡罗模拟方法,计算得到了密闭实验大厅内中子的体通量,以及不同位置处的散射中子注量,并将模拟得到的体通量和散射中子注量拟合成便于工程实践中应用的解析表达式,拟合结果与模拟结果的相对偏差小于10%。研究结果表明,球形空间内中子的体通量与球半径的1.905次方成反比;密闭实验大厅的中子体通量与大厅横截面宽度的1.948次方成反比,与长宽比的0.775次方成反比;球形空间结构内,每个源中子的平均径迹长度约为半径的5.4倍,而长方体密闭实验大厅内,单个源中子的平均径迹长度为大厅特征尺度的2~3倍。