The structure relaxation of carbon nanotube

A simple macroscopic continuum elasticity theory (CET) is used to calculate the structure relaxation of single-wall carbon nanotube (SWNT), an analytic formula is obtained. We also expand an atomic scale three-parameter empirical model [ T. Lenosky {\emph et al.} Nature 355, 333(1992)] in order to correctly describe the bond-length change effects. The structure relaxation of SWNT expected by the model is good in agreement with our CET results, and very well consistent with the previous calculation from a first principles local density function approximation. Using the expanded Lenosky model, we calculate the strain energy of bending tube. The obtained results are good in agreement with the previous theoretical expectation. It shows the model may be a good simple replacement of some more sophisticated methods on determining carbon networks deformations.Comment: 9 pages, 4 eps figure

Transvaginal versus transabdominal specimen extraction surgery for right colon cancer: A propensity matching study

BackgroundThe transvaginal route for specimen extraction is considered ideal for colorectal surgery, but its safety is still questioned. There has been little research on transvaginal natural orifice specimen extraction surgery (NOSES) in the right hemicolectomy. As a result, we conducted a study comparing transvaginal NOSES to traditional transabdominal specimen extraction surgery.Patients and methodsData on female patients who underwent radical right hemicolectomy at the First Affiliated Hospital of Nanchang University between January 2015 and December 2020 were collected retrospectively. A total of 847 patients were compliant, with 51 undergoing the transvaginal specimen extraction surgery (NOSES) group and 796 undergoing the transabdominal specimen extraction surgery (TISES) group. A propensity score matching method (1:2) was used to balance the clinicopathological characteristics of the two groups.ResultsFinally, 138 patients were enrolled in our study, with 46 in the NOSES group and 92 in the TISES group. Compared to the TISES group, the NOSES group had less intraoperative blood loss (p = 0.036), shorter time to first flatus (p < 0.001), shorter time to first liquid diet (p < 0.001), lower postoperative white blood cell counts (p = 0.026), lower C-reactive protein levels (p = 0.027), and lower visual analog scale (VAS) scores (p < 0.001). Regarding the quality of life after surgery, the NOSES group had better role function (p < 0.01), emotional function (p < 0.001), and improved symptoms of postoperative pain (p < 0.001) and diarrhea (p = 0.024). The scar satisfaction was significantly higher in the NOSES group than in the TISES group. Overall survival and disease-free survival in two groups were similar.ConclusionThe short-term results of transvaginal NOSES were superior to conventional transabdominal specimen extraction surgery. At the same time, transvaginal NOSES could improve the abdominal wall appearance and quality of life. The long-term survival was similar in the two surgical approaches. Therefore, transvaginal NOSES is worthy of our implementation and promotion

Ruling out real-valued standard formalism of quantum theory

Standard quantum theory was formulated with complex-valued Schrodinger equations, wave functions, operators, and Hilbert spaces. Previous work attempted to simulate quantum systems using only real numbers by exploiting an enlarged Hilbert space. A fundamental question arises: are complex numbers really necessary in the standard formalism of quantum theory? To answer this question, a quantum game has been developed to distinguish standard quantum theory from its real-number analog by revealing a contradiction in the maximum game scores between a high-fidelity multi-qubit quantum experiment and players using only real-number quantum theory. Here, using superconducting qubits, we faithfully experimentally implement the quantum game based on entanglement swapping with a state-of-the-art fidelity of 0.952(1), which beats the real-number bound of 7.66 by 43 standard deviations. Our results disprove the real-number formulation and establish the indispensable role of complex numbers in the standard quantum theory.Comment: submitted on March 202

Plasmoid ejection and secondary current sheet generation from magnetic reconnection in laser-plasma interaction

Reconnection of the self-generated magnetic fields in laser-plasma interaction was first investigated experimentally by Nilson {\it et al.} [Phys. Rev. Lett. 97, 255001 (2006)] by shining two laser pulses a distance apart on a solid target layer. An elongated current sheet (CS) was observed in the plasma between the two laser spots. In order to more closely model magnetotail reconnection, here two side-by-side thin target layers, instead of a single one, are used. It is found that at one end of the elongated CS a fan-like electron outflow region including three well-collimated electron jets appears. The ($>1$ MeV) tail of the jet energy distribution exhibits a power-law scaling. The enhanced electron acceleration is attributed to the intense inductive electric field in the narrow electron dominated reconnection region, as well as additional acceleration as they are trapped inside the rapidly moving plasmoid formed in and ejected from the CS. The ejection also induces a secondary CS

Single- and multi-walled carbon nanotubes viewed as elastic tubes with Young's moduli dependent on layer number

The complete energy expression of a deformed single-walled carbon nanotube (SWNT) is derived in the continuum limit from the local density approximation model proposed by Lenosky {\it et al.} \lbrack Nature (London) {\bf 355}, 333 (1992)\rbrack and shows to be content with the classic shell theory by which the Young's modulus, the Poisson ratio and the effective wall thickness of SWNTs are obtained as $Y=4.70$TPa, $\nu=0.34$, $h=0.75{\rm \AA}$, respectively. The elasticity of a multi-walled carbon nanotube (MWNT) is investigated as the combination of the above SWNTs of layer distance $d=3.4 {\rm \AA}$ and the Young's modulus of the MWNT is found to be an apparent function of the number of layers, $N$, varying from 4.70TPa to 1.04TPa for N=1 to $\infty$.Comment: 4 pages, 1 figur

Superconductivity at 41.0 K in the F-doped LaFeAsO1-xFx

Here we report the superconductivity in the LaFeAsO1-xFx system prepared by high pressure synthesis. The highest onset superconducting transition temperature (Tc) in this La-based system is 41.0 K with the nominal composition of LaFeAsO1-xFx (x = 0.6), which is higher than that reported previously by ambient pressure synthesis. The increase of Tc can be attributed to the further shrinkage of crystal lattice that causes the stronger chemical pressure on the Fe-As plane, which is induced by the increased F-doping level under high pressure synthesis