The QCD Ground State Chiral Tetrahedron Symmetry

We propose that the exotic meson tetraquark ud~dũintroduced in previous papers, may be a pseudo-Goldstone boson having a tetrahedron geometry and symmetry. The transition from the neutral pion superposition of two free mesons, dd~ and uũ, to the tetrahedron geometry with optional two chiral states may be the symmetry breaking of the QCD ground state. The ud~dũtetrahedron mass may be calculated by measuring the β decay rate variability. We assume that electrons and positrons are composite particle exotic tetraquarks, dũdd~ for the electrons and ud~dd~ for the positrons and confined by the strong force. We propose that the QCD tetrahedrons play a central role in electron pairing mechanism in both chemical bond forming and superconductor Cooper pairs. We propose a hypothesis where the QCD ground state tetrahedrons play a central role in low energy physics where quark exchange reactions between particles and the QCD tetrahedrons via gluon junctions transfer all the forces. The QCD ground state ud~dũtetrahedrons hypothesis provides a symmetry breaking and a mass gap may be created by the ground state QCD tetrahedrons Bose-Einstein condensate.

Robust Delaunay Tetrahedronal Meshing Coupled with Advancing Front Method

A full automatic tetrahedronal mesh generation method for arbitrary 3D domains is described. First, the classic Delaunay method is coupled with simplified advancing front technique (AFT) to obtain the boundary mesh. Then, advancing front high quality point placement is used to generate internal points with optimal positions and a Delaunay method is used to insert them efficiently. Finally, optimization procedures are used for mesh quality improvements. Several application examples are presented to demonstrate the robustness and efficiency of the proposed meshing scheme.

The Optical Resolution of Chiral Tetrahedrone-type Clusters Contai- ning SCoFeM (M=Mo or W) Using High Performance Liquid Chromatography Chiral Stationary Phase

Amylose tris (phenylcarbamate) chiral stationary phase (ATPC-CSP) was prepared and used for optical resolution of clusters 1 and 2. n-Hexane/2-propanol ( 99/1; v/v) were found to be the most suitable mobile phase on ATPC-CSP.

Multipartite Entanglement of a Tetrahedron Lattice

Three-dimensional Heisenberg model in the form of a tetrahedron lattice is investigated. The concurrence and multipartite entanglement are calculated through 2-concurrence C and 4-concurrence C4. The concurrence C and multipartite entanglement G4 depend on different coupling strengths Ji and are decreased when the temperature T is increased. For a symmetric tetrahedron lattice, the concurrence C is symmetric about J1 when J~ is negative while the multipartite entanglement G4 is symmetric about J1 when J2 〈 2. For a regular tetrahedron lattice, the concurrence G of ground state is 1/3 for ferromagnetic case while G = 0 for antiferromagnetic ca.se. However, there is no multipartitc entanglement since C4=0 in a regular tetrahedron lattice. The external magnetic field 13 can increase the maximum value of the concurrence GB and induce two or three peaks in Cn. There is a peak in the multipartite entanglement G4 B when G4B is varied as a function of the temperature T. This peak is mainly induced by the magnetic field B.

Locomotion Optimization and Manipulation Planning of a Tetrahedron-Based Mobile Mechanism with Binary Control

Locomotion and manipulation optimization is essential for the performance of tetrahedron-based mobile mechanism. Most of current optimization methods are constrained to the continuous actuated system with limited degree of freedom(DOF), which is infeasible to the optimization of binary control multi-DOF system. A novel optimization method using for the locomotion and manipulation of an 18 DOFs tetrahedron-based mechanism called 5-TET is proposed. The optimization objective is to realize the required locomotion by executing the least number of struts.Binary control strategy is adopted, and forward kinematic and tipping dynamic analyses are performed, respectively.Based on a developed genetic algorithm(GA), the optimal number of alternative struts between two adjacent steps is obtained as 5. Finally, a potential manipulation function is proposed, and the energy consumption comparison between optimal 5-TET and the traditional wheeled robot is carried out. The presented locomotion optimization and manipulation planning enrich the research of tetrahedron-based mechanisms and provide the instruction to the successive locomotion and operation planning of multi-DOF mechanisms.

A New Kind of Conjugate-nested Central Configurations in Consisted of One Regular Tetrahedron and One Regular Octahedron

A new case configuration in R^3, the conjugate-nest consisted of one regular tetrahedron and one regular octahedron is discussed. If the configuration is a central configuration, then all masses of outside layer are equivalent, the masses of inside layer are also equivalent. At the same time the following relation between ρ（r =√3/3ρ is the radius ratio of the sizes） and mass ratio τ=~↑m/m must be satisfied τ=~↑m/m=ρ（ρ＋3）（3＋2ρ＋ρ^2）^-3/2＋ρ（-ρ＋3）（3-2ρ＋ρ^2）^-3/2-4.2^-3/2ρ^-2-^-1ρ^-2/2（1＋ρ）（3＋2ρ＋ρ^2）^-3/2＋2（ρ-1）（3-2ρ＋ρ^2）^-3/2-4（2√2）^-3ρ, and for any mass ratio τ, when mass ratio r is in the open interval （0, 0.03871633950 ... ）, there exist three central configuration solutions（the initial configuration conditions who imply hamagraphic solutions） corresponding radius ratios are r1, r2, and r3, two of them in the interval （2.639300779… , ＋∞） and one is in the interval （0.7379549890…, 1.490942703… ）. when mass ratio τ is in the open interval （130.8164950… , ＋∞）, in the same way there have three corresponding radius ratios, two of them in the interval （0, 0.4211584789... ） and one is in the interval （0.7379549890…, 1.490942703…）. When mass ratio τ is in the open interval （0.03871633950…, 130.8164950…）, there has only one solution r in the interval （0.7379549890…, 1.490942703… ）.

Eight-body central configuration for conjugate-nested regular tetrahedrons

The sufficient and necessary conditions, the existence and uniqueness of a new class of central configuration in R^3, for the conjugate-nest consisting of two regular tetrahedrons, are proved. If the configuration is a central configuration, then all masses of outside layer are equivalent, and the masses of inside layer are also equivalent. At the same time p （the ratio of the sizes） and mass ratio τ=m^/m must be satisfied by some formulas. For any radius ratios ρ∈（0, 0.152996 918 2） or （0.715 223 148 7, 1.398 165 037）, there is only one central configuration. Otherwise, for any given mass ratio τ, there may exist more than one central configuration.

Numerical Experiment for Dipole-Dipole Interaction in Electro-Magnetism with Help of a Regular Tetrahedron

Aim of this work is to try to explain, on a Rational basis, some equations of Electro-Magnetism, which are based on Experimental data. Any Electric Field can produce a Field of many small Electric Dipoles, continuously distributed in space. In a region, where the Electric Field is constant, in direction and magnitude, all the small Dipoles are parallel to the Electric Field, and are represented by a single, long, parallel to them, fixed in space, Electric Dipole, which is here called Compass. An Alternating current, in a straight Conductor, is studied, by a simple, short computer program, for step-by-step nonlinear dynamic analysis. It is found that, only an Alternating current, not a direct current, can produce an Electric Dipole, in a straight Conductor. The two above Dipoles (Compass-Conductor) are assumed with equal lengths ℓ, lying on two skew lines, perpendicular to each other, at a distance ℓ√2, thus forming, by their four ends, a Regular Tetrahedron, with side length ℓ. Repulsion, between Like Charges, obeys the simple Coulomb Electro-Static law. Whereas Interaction (Attraction or Repulsion), between Unlike Charges, obeys a more accurate Lennard-Jones law. The analysis of Dipole-Dipole (Compass-Conductor) Interaction is performed by hand calculator. The only out-of-balance forces, in the regular Tetrahedron, acting on the Rigid Conductor, are the so-called magnetic forces. Their direction is found, in a simple Rational way, with help of Regular Tetrahedron, without recoursing to a “right-hand-rule”. The proposed model is applied to 1) The force acting on an Electric Charge moving in a magnetic field. 2) The force acting on a Current carrying straight Conductor, due to a magnetic field. 3) The magnetic fields created around a Current carrying straight Conductor. In these applications, proposed model gives reasonable results. Particularly, in third application, results, obtained by proposed model, are found in satisfactory approximation with corresponding ones, obtained by an empirical formula, based on relevant Experimental observations of H.-C. Oersted and A.-M. Ampère. So, the reliability of proposed model is checked. Position and direction of magnetic field vector coincide with those of a corresponding fixed Compass of a constant Electric Field. Main point of present work is that, without introducing the concept of a magnetic field vector, by combining field of dipoles, produced by an electric field, with dipole of an alternating current carrying conductor, the magnetic forces can be determined.

浅谈塑料离合踏板臂使用Tetrahedron有限元网格的后处理

汽车轻量化为节能减排作出了巨大贡献,而“以塑代钢”是轻量化中很常用的途径。有限元分析作为“以塑代钢”中一个非常重要的评估工具,约束其分析准确性的因素除了材料参数的定义、有限元分析模型的建立之外,还有有限单元网格的选择。对于壁厚不均匀的塑料离合踏板臂,使用Tetrahedron网格类型进行有限元分析,后处理时最大节点应力以及此网格单元的最大积分点应力也会有差异。结果显示,网格密度、积分点数量的变化对积分点应力的变化相对更小。

Enzymatically controlled DNA tetrahedron nanoprobes for specific imaging of ATP in tumor

Intracellular ATP is an emerging biomarker for cancer early diagnosis because it is a key messenger for regulating the proliferation and migration of cancer cells.However,the conventional ATP biosensing strat-egy is often limited by the undesired on-target off-tumor interference.Here,we reported a novel strategy to design enzymatically controlled DNA tetrahedron nanoprobes(En-DT)for biosensing and imaging ATP in tumor cells.The En-DT was designed via rational engineering of structure-switching aptamers with the incorporation of an enzyme-activatable site and further conjugation on the DNA tetrahedron.The En-DT could be catalytically activated by apurinic/apyrimidinic endonuclease 1(APE1)in cancer cells,but they did not respond to ATP in normal cells,thereby enabling cancer-specific ATP biosensing and imaging in vitro and in vivo with improved tumor specificity.This strategy would facilitate the precise detection of a broad range of biomarker in tumors and may promote the development of smart probes for cancer diagnosis.

DNA tetrahedron-based split aptamer probes for reliable imaging of ATP in living cells

Accurate detection and imaging of adenosine triphosphate(ATP)expression levels in living cells is of great value for understanding cell metabolism,physiological activities,and pathologic mechanisms.Here,we developed a DNA tetrahedron-based split aptamer probe(TD probe)for ratiometric fluorescence imaging of ATP in living cells.The TD probe is constructed by hybridizing two split ATP aptamer probes(Apt-a and Apt-b)to a DNA tetrahedron assembled by four DNA oligonucleotides(T1,T2,T3 and T4).In the presence of ATP,the TD probe will alter its structure from the open to closed state,thus bringing the separated donor and acceptor fluorophores into close proximity for high fluorescence resonance energy transfer(FRET)signals.The TD probe exhibits low cytotoxicity,efficient cell internalization and good biological stability.Moreover,based on the FRET“off”to“on”signal output mode,the TD probe can effectively avoid false-positive signals from complex biological matrices,which is significant for long-term reliable imaging in living cells.In addition,by changing the split aptamers attached to DNA tetrahedron,the proposed strategy may be extended for detecting various intracellular targets.Collectively,this strategy provides a valuable sensing platform for biomarkers analysis in living cells,thus having great potential for early clinical diagnosis and therapeutic evaluation.

中国舞蹈艺术的审美文化观——内外部相融的舞蹈研究方法论探讨

舞蹈创作和批评研究既包括“生命体”身体意识和时空关系的内部规律探讨,也要阐释舞蹈与人类其他社会实践的外部规律联系,内外部结合的方法论很有意义。舞蹈分析与动作分析并非相同概念。舞蹈创作和研究从业者除了提升动作分析理论,还应密切关注新的编舞走向和跨学科的舞蹈研究趋势。20世纪八九十年代以来,西方舞蹈学者的舞蹈分析框架,融入了文化研究,揭示出仅作动作分析或内部研究的局限性;中国舞蹈学者的元素分析、形态分析也与舞蹈文化密切相关。在全球在地化和全媒体时代,作为一种方法论,舞蹈艺术的“审美文化观”将舞蹈创作到批评视为审美文化活动,承袭了古今中西文化汇通的中国美学、文学、理论界和舞蹈学的相关研究,自律论、他律论与通律论相辅相成,重视具体的真实的人本体,一方面强调侧重内部研究的“跨媒介性”视角,另一方面也倡导将内外部打通的“跨文化”观,尝试既在审美中看舞蹈文化,也在文化中看舞蹈审美,是一种具有“中国式现代化”路径的文艺观和方法论。“点线面体”充分融合的审美文化四面体图式,基于艾布拉姆斯“四要素”三角和格里斯沃尔德“文化菱形”理论基础,融入拉班动作分析四面体思路,并与中国人文社科学术界倡导多年的“审美文化”研究相通。

考虑自由液面影响的多凸体结构浮态计算方法

针对液舱内自由液面对浮态和稳性的影响,文中提出了一种新的多凸体组合结构浮态算法。该方法将浮体和液舱分解成多个四面体单元,通过分析每个四面体与水面/液面的相对位置关系来确定浮体的浮力和浮心以及液舱液体的重心。该方法还提出了一种改进的双重迭代法用来确定多凸体组合结构的浮态:内层迭代法模拟浮体的升沉运动,得到浮体外的水面方程和液舱内的液面方程;通过外层迭代法模拟浮体的旋转运动。两种迭代方法交替进行,直至浮体的重力作用线和浮力作用线之间的距离满足精度要求,同时重力等于浮力。自编程序对某半潜船和某半潜式海洋平台的多种典型工况进行了浮态计算,同时也考虑了自由液面影响。此外利用Maxsurf建模进行了对比分析,还利用AUTOCAD进行了精度验证。对照结果表明:该研究提出的算法可以考虑自由液面对浮态的影响,原理清晰,收敛性好;算法无论对传统的单凸体结构(例如单体船),还是多凸体结构(例如多体船、漂浮式海洋平台等)均更容易取得准确解,且计算效率更高;算法可以实现“搭积木”式的建模方式,多工况建模时可以极大地减小工作量;算法无需依赖国外第三方图形平台(比如AUTOCAD、CATIA),可为我国相关工业软件的国产化打下良好的基础。

交错断层四面体自适应网格分级细化研究

目前四面体自适应网格细化技术多集中于简单层状地质体的三维重构与表达分析,对结构复杂、数据不连续的含交错断层等地质体进行自适应网格细化时,易出现过度细化,导致断层区域的网格结构受到影响。为了提高含复杂断层四面体网格模型的精度,提出一种适用于交错断层的四面体自适应网格分级细化方法。首先,根据断层影响范围公式,自适应确定断层网格附近的细化范围;其次,构建四面体和四面体边的分级细分公式,确定细化范围内的四面体和四面体边的分级;然后,针对四面体网格细分时出现的多种情况,通过对边的升级处理,将细分的8种类型统一为3种类型;最后,在细化范围内,通过新增加顶点和原顶点重新连接四面体,改变网格的单元尺寸,生成高质量的网格模型。以内蒙古自治区某含交错断层露天煤矿的四面体网格模型为例,使用三维网格质量评估算法及FLAC3D模拟软件分析细化前后的网格模型,结果表明:细化后的网格模型失真值从0.3317降低到0.3061,表明网格的质量得到提升;在相同参数下,未细化模型的最大位移为1.16 m,稳定性系数为1.27,分级细化后模型的最大位移为1.29 m,稳定性系数为1.23;细化后模型的位移云图处于断层处,且能够体现断层分布特征和断层对边坡的影响规律,而未细化模型的位移云图的位置偏离断层中心,断层对边坡的影响效果不明显。

基于四面体特征的面阵激光雷达与相机标定方法

为了提高面阵激光雷达与相机标定精度,提出了一种基于四面体结构的面阵激光雷达与相机标定方法。利用图像中角点的反投影射线和点云中直线特征建立“点-三线”的对应关系,提高了约束强度,根据异面直线间的距离和投影直线间的夹角建立约束方程,通过非线性优化求解相机和雷达坐标系间的变换向量并最终得到变换矩阵。构建三角板和地面组成的四面体结构并进行实验验证,实验结果表明:该方法的平均投影误差在0.6像素以内,优于其他两种标定方法,为后续激光雷达数据与图像数据融合提供了研究基础。

零耦合度Stewart型并联机器人的位置正解个数

一般六自由度并联机构的位置正解是继空间7R(R:转动副)机构位移分析完成后的又一机构学难题,目前数学上尚无完备的解析求解方法。以零耦合度的“3-2-1”式Stewart型并联机器人为例,研究了位置正解的个数,并分析了正解个数发生变化的条件。首先,基于杆长约束方程并运用四面体原理,解析推导了机器人位置正解的全部8组解。其次,通过分析动球铰的位置特性,挖掘出正解方程分别为8组、4组、2组、1组解析解时,所需满足的数学条件。接着,根据静球铰位置特性并结合正解算法流程,研究了影响正解方程实数解个数的因素。最后,剖析了并联机器人位置正解个数与Hunt奇异之间的内在联系。研究结论为并联机器人的实时控制和轨迹规划奠定了理论基础。

Solid rocket motor propellant grain burnback simulation based on fast minimum distance function calculation and improved marching tetrahedron method

To efficiently compute arbitrary propellant grain evolution of the burning surface with uniform and non-uniform burning rate for solid rocket motor,a unified framework of burning surface regression simulation has been developed based on minimum distance function.In order to speed up the computation of the mini-mum distance between grid nodes of grain and the triangular mesh of burning surface,a fast distance querying method based on the equal size cube voxel structure was employed.An improved marching tetrahedron method based on piecewise linear approximation was carried out on second-order tetrahedral elements,achieved high-efficiency and adequate accuracy of burning surface extraction simultaneously.The cases of star grain,finocyl grain,and non-uniform tube grain were studied to verify the proposed method.The observed result indicates that the grain burnback computation method could realize the accurate simulation on unstructured tetrahedral mesh with a desirable performance on computational time.

Electronic transport through tetrahedron-structured DNA-like system

We theoretically investigate the electronic transport properties of a multi-terminal tetrahedronstructured DNA under a uniform magnetic field. Based on a tight-binding model, the current and nonlocal resistance are calculated under different situations by employing the Landauer Biittiker formula. Our results indicate that the current, displays a clear sign of interference in the presence of the magnetic field and can be mainly divided into three patterns, as demonstrated by the Fourier transformation. Furthermore, the tetrahedron-structured DNA can be used as a molecular switch. The underlying physical mechanisms are analyzed for the various phenomena observed in this threedimensional DNA interferometer.

Efficient renal clearance of DNA tetrahedron nanopartides enables quantitative evaluation of kidney function

DNA tetrahedro n nano structure (DTN) is one of the simplest DNA nano structures and has bee n successfully applied for biose nsin g, imagi ng, and treatment of can cer. To facilitate its biomedical applications and pote ntial clinical tran slation, fun dame ntal un derstandi ng of DTN's transportation among major organs in living organisms becomes increasingly important. Here, we describe the efficient renal clearanee of DTN in healthy mice by using positron emission tomography (PET) imaging. The kidney elimination of DTN was later applied for renal function evaluation in murine models of unilateral ureteral obstruction (UUO). We further established a mathematical program of DTN to validate its changes of transportation pattern in healthy and UUO mice. We believe the establishment of pharmacokinetic profiles and mathematical model of DTN may provide in sight for future optimization of DNA nano structures for biomedical applications.

3D Numerical Simulation of Non-isothermal Resin Transfer Molding Filling Process Using Unstructured Tetrahedron Mesh

We present a numerical formulation for resin flow based on the concept of quasi-steady state situation at the flow front. To be fit for complicated product shapes,we use the four-node unstructured tetrahedron mesh based on which the numerical formulation of temperature and degree of cure is developed. The validity of our method is established in the case where ffexible meshes are used. The results show that the numerical procedure,tested on known data,provides numerically valid and reasonably accurate predictions.