Study on the Size Distribution and Similarity Law of Bubble Nuclei in Water

To study the distribution characteristics and similarity laws of nuclei under different pressures,based on the selfdesigned decompression chamber and the acoustic measuring system,the size distributions of nuclei in the degassed tap water under negative ambient pressures were measured.A number density distribution function of nuclei based on the modified Weibull distribution function was proposed and verified by the experimental measurement results and some published data of nuclei size distribution.Based on this nuclei number density distribution function,the similarity law of the nuclei size distribution was analyzed:in the scale experiment,the value of exponential in the similarity law of the nuclei number density should be determined by the nuclei size distribution of the water in the prototype experiment and the actual nuclei size distribution of the water in the model experiment.And a precondition is that the nuclei size distributions are similar.

The Golden Ratio Theorem: A Framework for Interchangeability and Self-Similarity in Complex Systems

The Golden Ratio Theorem, deeply rooted in fractal mathematics, presents a pioneering perspective on deciphering complex systems. It draws a profound connection between the principles of interchangeability, self-similarity, and the mathematical elegance of the Golden Ratio. This research unravels a unique methodological paradigm, emphasizing the omnipresence of the Golden Ratio in shaping system dynamics. The novelty of this study stems from its detailed exposition of self-similarity and interchangeability, transforming them from mere abstract notions into actionable, concrete insights. By highlighting the fractal nature of the Golden Ratio, the implications of these revelations become far-reaching, heralding new avenues for both theoretical advancements and pragmatic applications across a spectrum of scientific disciplines.

EXTENDED SELF SIMILARITY OF PASSIVE SCALAR IN RAYLEIGH-BNARD CONVECTION FLOW BASED ON WAVELET TRANSFORM

Wavetet transform was used to analyze the scaling law of temperature data (passive scalar) in Rayleigh-Bénard convection flow from two aspects. The first one was to utilize the method of extended self similarity, presented first by Benzi et al., to study the scaling exponent of temperature data. The obtained results show that the inertial range is much wider than that one determined directly from the conventional structure function, and find the obtained scaling exponent agrees well with the one obtained from the temperature data in an experiment of wind tunnel. The second one was that, by extending the formula which was proposed by A. Arneodo et al. for extracting the scaling exponent ζ(q) of velocity data to temperature data, a newly defined formula which is also based on wavelet transform, and can determine the scaling exponent ξ(q) of temperature data was proposed. The obtained results demonstrate that by using the method which is named as WTMM (wavelet transform maximum modulus) ξ(q) correctly can be extracted.

结合Cannikin’s Law的离线数据增广方法研究

数据增广是提升深度学习模型性能的有效方法之一。针对多类别目标检测任务中检测性能不平衡问题,提出一种针对“短板类别”(检测性能远低于模型平均检测性能的类别)的离线数据增广方法。受Cannikin’s Law的启发,采用基于复制粘贴(copy-paste)机制的场景多样性增广方法。随机采集训练集中“短板类别”实例区域,通过相似性度量机制选取训练集中增广目标样本进行随机粘贴。为了降低随机粘贴导致的遮挡问题,采用基于自遮挡(cut-replace)机制的增广方法提升模型遮挡表达能力。通过截取样本自身区域,对特征表达最显著区域进行遮挡。实验表明,FCOS目标检测框架在PASCAL VOC数据上的平均检测精度(mean average precision,mAP)从79.10%提升到83.90%,其中短板类别更为显著,提升了20.8个百分点。在MS-COCO数据上平均检测精度提升了0.9个百分点。

民企内部腐败犯罪的立法修正与学理解析

民企内部腐败犯罪本质上是企业内部人员利用职务便利,搞非法利益输送,损害企业的利益。对于民企内部腐败犯罪的刑法规制关涉民营经济的高质量发展,理应秉持最后手段性,在其他治理手段无效时才能动用。《刑法修正案(十二)》强化对民企内部腐败犯罪的惩治力度,实质上仍属未超出限度的有限惩罚,是对积极刑法主义的践行,关键在于要处理好追究企业内部腐败与尊重企业自主经营之间的关系。这也是把握此次立法修订的范围、准确适用非法经营同类营业罪、为亲友非法牟利罪等具体犯罪应当遵循的基本准则。

电路的量纲模型与相似性原理和对偶性原理

宇宙量纲模型的思想适用于任何系统,物理系统适用,电路系统也同样适用。系统地分析总结了电路运行的基本原理,确定了电路系统的量纲,提出了电路的量纲模型、相似性原理和对偶性原理及规律拓展性原理等概念,并给出了相似性原理和对偶性原理的一些应用实例。

我国背信犯罪的教义学阐释——以《刑法修正案(十二)》为起点

背信犯罪的目的型法益是财产,手段型法益是信任,其中“信任”法益居于从属地位。背信犯罪的主体是为他人处理事务者,这里的“事务”应具有财产性和“他人性”,“利他性”不等于“他人性”。非法经营同类营业罪的特征是“干自己的事,使单位受损”,因此不是背信犯罪。背信犯罪的事务应具有裁量性,不包括纯粹机械性劳务。德国将背信罪分为“滥用权限型”与“违背信任型”,将越权代理归入后者。然而,罪名的行为类型应是并列关系,而非包含关系,且滥用代理权与超越代理权在财产损失的认定上没有区别。背信犯罪的行为类型应划分为不当代理行为和非代理行为,前者涉及内部关系和外部关系,后者仅涉及内部关系。传统观点认为,一项罪名要么是针对个别财产的犯罪,要么是针对整体财产的犯罪,这种看法过于绝对。盗窃罪、诈骗罪及背信犯罪均存在针对个别财产的情形和针对整体财产的情形。在三方给付的场合认定整体财产损失,应以全部给付(担保人给付)时为时间标准。

类案类判:道德应当还是法律应当

类案类判具有法律应当与道德应当的双重属性,将其定位于纯粹的道德应当或法律应当面临诸多困境。因此,我们有必要在理论构造层面构建两者之间的协同实现机制,探求类案类判在司法实践中的实现规程。总体而言,法律应当优先于道德应当是较为现实的选择,也是形式正义的基本要求,但法律应当优先并不当然否定法官道德应当的反思精神。道德应当是实现实质正义必不可少的重要环节,在时势变更、法律修订等特殊情形下,道德应当的地位需优于法律应当。具体而言,在理论构造层面要坚持法律应当优先前提下的道德应当优先的兼顾;在实践层面要坚持道德应当指导下的法律应当制度化推进。

榆树泉矿煤层开采覆岩破坏物理模拟试验研究

为研究煤层开采覆岩破坏情况,以榆树泉矿为工程背景,采用物理相似模拟试验,分析了煤层开采过程中覆岩的破坏规律,结合经验公式计算,确定了煤层开采覆岩导水裂隙带高度。结果显示,随着煤层开采,覆岩裂隙在纵向上的发育速度减缓,横向裂隙发育速度加快,范围扩大,且近工作面处的裂隙逐步向破碎型裂隙发展。覆岩形态在横向、纵向以及整体上呈现出先扩展延伸而后趋于稳定的特点,覆岩形态最终趋于“马鞍形”。覆岩位移量随着距煤层工作面垂直距离的增加而减小,并且位移量由两侧向中部递减。模拟导水裂隙带的发育最大高度为65 m,与经验公式计算的结果吻合,裂采比约为16。研究结果可为榆树泉矿顶板水害防治提供科学依据。

不同航速下SUBOFF流噪声频谱相似律研究

研究流噪声与航速关系可以有效地解决高航速水下航行器流噪声预报的难题。基于Lighthill声类比理论,研究缩尺比为1∶24的SUBOFF模型在特定航速范围内的声源特性,得到了流噪声频域结果与航速关系,给出了不同航速下基于斯特劳哈尔数和航速关系的流噪声频谱换算方法。研究结果表明,随着航速的提高,SUBOFF声指向性形状基本不变,低频范围内声辐射具有偶极子特性,辐射声功率的大小与航速的6次方成正比。在同一流场模型下,基于偶极子换算关系下的高航速原型预报值和大涡模拟计算值总声功率级和总声源级误差分别为1.2 dB和2.3 dB。

Time-fractional Davey–Stewartson equation:Lie point symmetries,similarity reductions,conservation laws and traveling wave solutions

As a celebrated nonlinear water wave equation,the Davey–Stewartson equation is widely studied by researchers,especially in the field of mathematical physics.On the basis of the Riemann–Liouville fractional derivative,the time-fractional Davey–Stewartson equation is investigated in this paper.By application of the Lie symmetry analysis approach,the Lie point symmetries and symmetry groups are obtained.At the same time,the similarity reductions are derived.Furthermore,the equation is converted to a system of fractional partial differential equations and a system of fractional ordinary differential equations in the sense of Riemann–Liouville fractional derivative.By virtue of the symmetry corresponding to the scalar transformation,the equation is converted to a system of fractional ordinary differential equations in the sense of Erdélyi–Kober fractional integro-differential operators.By using Noether’s theorem and Ibragimov’s new conservation theorem,the conserved vectors and the conservation laws are derived.Finally,the traveling wave solutions are achieved and plotted.

类案检索技术研究综述

类案检索是法学和计算机相关学科的交叉应用,类案检索技术旨在通过类案判定获得候选检索结果。当前研究分别从法律和计算机两个视角展开,通过技术与领域的深度融合实现类案检索以精准服务法官判案需要,尽管类案检索技术研究逐渐体系化,但尚未存在相关技术发展的系统性综述。为此,首先分析在法学上类案界定标准的变化,以浅层和深层文本表示方法为划分标准,论述相似案例匹配技术研究进展;其次比较中国裁判文书网、“法信”“北大法宝”3类案检索平台的特点;最后提出构建大型标注数据集、设计可解释性算法和提升检索效率是未来类案检索技术的主要发展方向。实验表明,现阶段类案检索平台数量多,但大都处于起步阶段,缺乏具备可解释的稳定算法是影响其发展的重要因素。

综放工作面矿压显现规律与采煤工艺优化研究

针对某矿经常出现支架移动、倾倒、难伸缩、设备翻倒等现象,采用数值模拟、现场实测以及相似模拟的方法对某矿大倾角工作面采煤工艺进行优化研究,通过分析某矿大倾角工作面的围岩与顶板运移、破坏以及应力规律,对某矿综放工作面进行矿压监测以及矿压显现规律研究,优化了某矿大倾角综放工作面的采煤工艺,保证了工作面安全,使某矿大倾角综放工作面生产更安全高效。

Scaling laws of compressible turbulence

Spatial scaling laws of velocity kinetic energy spectra for the compressible turbulence flow and the density-weighted counterparts are formulated in terms of the wavenumber, dissipation rate, and Mach number by using a dimensional analysis. We apply the Barenblatt＇s incomplete similarity theory to both kinetic and density-weighted energy spectra. It shows that, within the initial subrange, both energy spectra approach the -5/3 and -2 power laws of the wavenumber when the Mach number tends to unity and infinity, respectively.

Drag characteristics of power law fluids on an upstream moving surface

The specific problem to be considered here concerns the boundary layer problem of a non-Newtonian fluid on a flat plate in length, whose surface has a constant velocity opposite in the direction to that of the mainstream with Uw 〉〉 U∞, or alternatively when the plate surface velocity is kept fixed but the stream speed is reduced to zero. A theoretical analysis for a boundary layer flow is made and the self-similar equation is determined. Solutions are presented numerically for special power index and the associated transfer behavior is discussed.

On energy boundary layer equations in power law non-Newtonian fluids

The hear transfer mechanism and the constitutive models for energy boundary layer in power law fluids were investigated.Two energy transfer constitutive equations models were proposed based on the assumption of similarity of velocity field momentum diffusion and temperature field heat transfer.The governing systems of partial different equations were transformed into ordinary differential equations respectively by using the similarity transformation group.One model was assumed that Prandtl number is a constant,and the other model was assumed that viscosity diffusion is analogous to thermal diffusion.The solutions were presented analytically and numerically by using the Runge-Kutta formulas and shooting technique and the associated transfer characteristics were discussed.

Similarities of Some Wind Input and Dissipation Source Terms

Wind input parameterizations proposed by Jeffreys, Sverdrup and Munk, and Plant are analyzed. It is found by analogy that the similarity of integrals of the three wind input parameterizations exists. Wave breaking dissipation parameterizations proposed by Tsikunov, Hasselmann, and Phillips are also analyzed. Likewise it is found by analogy that the similarity of integrals of the three dissipation parameterizations exists. The similarities of wind input and dissipation are applied to the investigation of the fetch-limited growth of wind waves, together with the 3/2 power law presented by Toba. Some semi-empirical formulas concerning the growth of wave height and period with fetch are presented. The results from the formulas are in good agreement with previous field observations.

Self-Similar Characteristic for the Ramp Structures of Wind Speed

Time series of wind speed are composed of large and small ramp structures. Data analysis reveals a power law relation between the linear slope of ramp structures and the time scale. This suggests that these ramp structures of wind speed have a self-similar characteristic. The lower limit of the self-similar scale range was 2 s. The upper limit is unexpectedly large at 27 min. Data are collected from grassland, city, and lake areas. Although these data have different underlying surfaces, all of them clearly show a power law relation, with slight differences in their power exponents.

多中段联合开采围岩扰动效应及采矿进路支护技术

受多次开采扰动影响,多中段联合开采过程中采场围岩稳定性差,地压显现剧烈,采矿进路支护难。以白象山铁矿-470,-430和-390 m中段联合开采工程为研究背景,采用大型相似材料模型试验及采场围岩数字照相变形量测技术,揭示多中段联合开采采场围岩应力变化特征及上覆岩层移动规律。研究结果表明:各中段逐分层向上回采对上覆岩层产生了累积叠加扰动效应,导致采场围岩反复承受荷载(多次扰动)而失稳破坏;各分层矿体下沉量随开采步的推进呈先增大后减小的趋势,采空充填区中部位置附近覆岩的下沉量最大,采场围岩变形具有明显的阶段性增长特征。各中段保留矿体(顶柱)对维持采场围岩稳定、减弱相邻中段间的采矿扰动和降低上覆岩层的变形破坏有积极的作用,受多中段联合开采扰动影响较大、完整性破坏严重的中段保留矿体中的应力可突然释放,出现了局部或整体失稳,威胁采场围岩整体稳定性。确定多中段联合开采扰动条件下采矿进路切圆拱断面形式,其拱高为2.0 m,提出锚网索喷联合支护技术,有效控制采矿进路围岩变形与破坏。

PELE侵彻金属靶破碎效应的相似分析

为了研究横向效应增强型侵彻体(penetrator with enhanced lateral effects,PELE)侵彻金属靶板破碎效应的相似规律,选取PELE的壳体破碎长度和靶后破片散布半径作为衡量PELE破碎效应的两个物理参量,基于量纲理论对PELE破碎效应问题进行相似分析,应用AUTODYN软件开展了4组相似模型数值模拟,并进行了两组相似模型验证试验。研究结果表明:通过相似理论分析,确定了PELE破碎效应满足严格的几何相似律。在800~2000 m/s撞击速度范围内,归一化处理的壳体破碎长度和靶后破片散布半径数值模拟结果及试验结果与几何尺寸无关,仅随撞击速度的提升呈线性增长,从而证明了PELE侵彻金属靶的破碎效应满足几何相似律。