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1. chinaXiv:201708.00371 [pdf]

Synchrotron X-ray tomographic microscopy reveals histology and internal structure of Galeaspida (Agnatha)

Subjects: Geosciences >> Geology

Synchrotron Radiation X-ray Tomographic Microscopy (SRXTM) is a powerful non-destructive method in paleontology, providing ultra-high-resolution 3D insights into the internal structure of fossils. Employing SRXTM, the skull specimens of Shuyu zhejiangensis, a 428 million-year-old galeaspid from the Silurian of Changxing, Zhejiang Province, are investigated. The subsequent analyses indicate that the endoskeletal skull of S. zhejiangensis is composed wholly of cartilage without convincing evidence for the presence of perichondral bone. The cranial anatomy of S. zhejiangensis are unusually preserved in three dimensions largely due to the non-random decay of the cartilaginous braincase and its connecting ‘soft’ tissues. Using Amira or Avizo software, seven virtual 3D endocasts of the skull of S. zhejiangensis were created revealing the gross internal cranial anatomy of galeaspids in great detail for the first time. The preliminary results indicate that during evolution the galeaspid head experienced a fundamental reorganization resulting in the development of jaws. 同步辐射X射线断层显微成像已经成为古生物研究中一种新的重要手段,能够在不损坏化石的前提下,提供化石内部超高分辨率的三维成像。利用瑞士光源最先进的同步辐射X射线断层显微成像技术,研究分析了七个采自浙江长兴志留系(约4.28亿年前)的早期盔甲鱼类浙江曙鱼三维立体保存脑颅化石。同步辐射X射线显微成像结果显示:盔甲鱼脑颅完全由软骨组成,并没有软骨外成骨存在的证据;盔甲鱼脑颅解剖结构能够被精细的保存下来,很大程度上归功于脑颅软骨与周围软组织在埋藏过程中的异时分解。利用AMIRA或AVIZO等计算机三维虚拟复原软件,三维虚拟复原了七个曙鱼脑颅模型,首次揭示出盔甲鱼脑颅内部详细的解剖结构。初步研究结果显示盔甲鱼的脑颅已经发生了显著的重组,具备了颌发育所必需的先决条件。

submitted time 2017-08-29 From cooperative journals:《古脊椎动物学报》 Hits3104Downloads821 Comment 0

2. chinaXiv:201708.00369 [pdf]


单建华; 吕钦; 张神林
Subjects: Mechanical Engineering >> Other Disciplines of Mechanical Engineering


submitted time 2017-08-29 Hits7673Downloads4880 Comment 0

3. chinaXiv:201708.00367 [pdf]


Subjects: Computer Science >> Information Security


submitted time 2017-08-28 Hits5125Downloads2979 Comment 0

4. chinaXiv:201703.00011 [pdf]

Calorimetric Power Measurements in the EAST ECRH System

Weiye Xu
Subjects: Physics >> Nuclear Physics

In this paper, the calorimetric power measurement method for electron cyclotron resonance heating system on EAST are presented. This method requires measurement of the water flow through the cooling circuits and the input and output water temperatures in each cooling circuit. Usually, the inlet water temperature is controlled to be stable to get more accurate results. The influence of the inlet water temperature change on the measurement results is analyzed for the first time in this paper. A novel temperature calibration method is proposed also. This kind of calibration method is accurate and effective, and can be easily implemented.

submitted time 2017-08-28 Hits3042Downloads1436 Comment 0

5. chinaXiv:201708.00366 [pdf]


陈皓勇; 葛海麟; 邱明
Subjects: Dynamic and Electric Engineering >> Electrical Engineering


submitted time 2017-08-28 Hits2831Downloads1184 Comment 0

6. chinaXiv:201708.00218 [pdf]


陈皓勇; 韩励佳
Subjects: Dynamic and Electric Engineering >> Electrical Engineering


submitted time 2017-08-27 Hits4652Downloads1601 Comment 0

7. chinaXiv:201708.00365 [pdf]

Mayer-Cluster Expansion of Instanton Partition Functions and Thermodynamic Bethe Ansatz

Carlo Meneghelli; Gang Yang
Subjects: Physics >> The Physics of Elementary Particles and Fields

In [18] Nekrasov and Shatashvili pointed out that the N = 2 instanton partition function in a special limit of the ?-deformation parameters is characterized by certain thermodynamic Bethe ansatz (TBA) like equations. In this work we present an explicit derivation of this fact as well as generalizations to quiver gauge theories. To do so we combine various techniques like the iterated Mayer expansion, the method of expansion by regions, and the path integral tricks for non-perturbative summation. The TBA equations derived entirely within gauge theory have been proposed to encode the spectrum of a large class of quantum integrable systems. We hope that the derivation presented in this paper elucidates further this completely new point of view on the origin, as well as on the structure, of TBA equations in integrable models.

submitted time 2017-08-25 Hits777Downloads369 Comment 0

8. chinaXiv:201708.00362 [pdf]

Cutting through form factors and cross sections of non-protected operators in N = 4 SYM

Dhritiman Nandan; Christoph Sieg; Matthias Wilhelm; Gang Yang
Subjects: Physics >> The Physics of Elementary Particles and Fields

: We study the form factors of the Konishi operator, the prime example of nonprotected operators in N = 4 SYM theory, via the on-shell unitarity method. Since the Konishi operator is not protected by supersymmetry, its form factors share many features with amplitudes in QCD, such as the occurrence of rational terms and of UV divergences that require renormalization. A subtle point is that this operator depends on the spacetime dimension. This requires a modification when calculating its form factors via the on-shell unitarity method. We derive a rigorous prescription that implements this modification to all loop orders and obtain the two-point form factor up to two-loop order and the three-point form factor to one-loop order. From these form factors, we construct an IR-finite crosssection-type quantity, namely the inclusive decay rate of the (off-shell) Konishi operator to any final (on-shell) state. Via the optical theorem, it is connected to the imaginary part of the two-point correlation function. We extract the Konishi anomalous dimension up to two-loop order from it.

submitted time 2017-08-25 Hits912Downloads470 Comment 0

9. chinaXiv:201708.00361 [pdf]

On-Shell Methods for the Two-Loop Dilatation Operator and Finite Remainders

Florian Loebbert; Dhritiman Nandan; Christoph Sieg; Matthias Wilhelm; Gang Yang
Subjects: Physics >> The Physics of Elementary Particles and Fields

We compute the two-loop minimal form factors of all operators in the SU(2) sector of planar N = 4 SYM theory via on-shell unitarity methods. From the UV divergence of this result, we obtain the two-loop dilatation operator in this sector. Furthermore, we calculate the corresponding finite remainder functions. Since the operators break the supersymmetry, the remainder functions do not have the property of uniform transcendentality. However, the leading transcendentality part turns out to be universal and is identical to the corresponding BPS expression. The remainder functions are shown to satisfy linear relations which can be explained by Ward identities of form factors following from R-symmetry

submitted time 2017-08-25 Hits831Downloads377 Comment 0

10. chinaXiv:201708.00360 [pdf]

Master integrals for the four-loop Sudakov form factor

Rutger H. Boels; Bernd A. Kniehl; , Gang Yang
Subjects: Physics >> The Physics of Elementary Particles and Fields

The light-like cusp anomalous dimension is a universal function in the analysis of infrared divergences. In maximally (N = 4) supersymmetric Yang– Mills theory (SYM) in the planar limit, it is known, in principle, to all loop orders. The non-planar corrections are not known in any theory, with the first appearing at the four-loop order. The simplest quantity which contains this correction is the four-loop two-point form factor of the stress tensor multiplet. This form factor was largely obtained in integrand form in a previous work for N = 4 SYM, up to a free parameter. In this work, a reduction of the appearing integrals obtained by solving integration-by-parts (IBP) identities using a modified version of Reduze is reported. The form factor is shown to be independent of the remaining parameter at integrand level due to an intricate pattern of cancellations after IBP reduction. Moreover, two of the integral topologies vanish after reduction. The appearing master integrals are cross-checked using independent algebraic-geometry techniques explored in the Mint package. The latter results provide the basis of master integrals applicable to generic form factors, including those in Quantum Chromodynamics. Discrepancies between explicitly solving the IBP relations and the MINT approach are highlighted. Remaining bottlenecks to completing the computation of the four-loop non-planar cusp anomalous dimension in N = 4 SYM and beyond are identified.

submitted time 2017-08-25 Hits792Downloads357 Comment 0

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