Phase Transformation of Nb in Carburized Zone of 25Cr35NiNb+MA Alloy After Service

Abstract25Cr35NiNb+MA alloy is widely used in ethylene pyrolysis furnace tube, the highest service temperature can be 1100°C, and has high resistance to creep and carburization. Ethylene pyrolysis furnace tube will suffer carburizing during service, which lead to phase transformation. Phase transformation of 25Cr35NiNb+MA heat-resistant ethylene pyrolysis furnace tube was investigated after service and the Nb transition during service was discussed. The phase transformation of ethylene pyrolysis furnace tube was characterized with field emission scanning electron microscopy (FE-SEM) equipped with energy dispersive spectrum (EDS). Results reveal that the microstructure of as-cast 25Cr35NiNb+MA alloy contains NbC carbides on the dendrite boundaries. During service at high temperature, the NbC carbides transform to blocky G-phase (Ni16Nb6Si7) between M23C6 and matrix. As the carburizing process occurs, the blocky G-phase (Ni16Nb6Si7) gradually transforms to granular NbC, and distribute at the center of chromium carbide. The granular NbC will improve resistance of creep

Comparative Study on Magnetic Properties and Microstructure of As-prepared and Alternating Current Joule Annealed Wires

AbstractX-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), magnetic measurement including impedance measurement were used for investigating the microstructure and magnetic properties of as-prepared and alternating current Joule annealed (ACJA) Co-rich amorphous microwires for potential sensor applications. Experimental results indicated that as-cast and ACJA wires both were amorphous characteristic, while ACJA wire has an enhanced local ordering degree of atom arrangement. There was a transform of magnetic properties after ACJA treatment, namely increasing coercivity, maximum magnetic permeability and saturation magnetization, resulting from the coactions of magnetic anisotropy and magnetic moment exchange coupling. Moreover, ACJA treatment can drastically improve the GMI property of melt-extracted wires. At 5MHz, the maximum GMI ratio [ΔZ/Z0]max of ACJA wire increases to 205.93%, which is nearly 4.1 times of 50.62% for as-cast wire, and the field response sensitivity ξmax of ACJA wire increases to 463.70%/Oe by more than 2 times of 212.15%/Oe for as-cast wire. From sensor application perspective, the sensor applied frequency range (SAFR) of ACJA wire is 3MHz-7MHz (the better working frequency is at 5MHz). It can therefore be concluded that the ACJA wire (60mA, 480s, 50Hz) has better GMI and magnetic properties, is more suitable for potential magnetic sensor applications working at low-frequency and relatively high-working-magnetic field

Superconductivity and single crystal growth of Ni0:05TaS2

Superconductivity was discovered in a Ni0:05TaS2 single crystal. A Ni0:05TaS2 single crystal was successfully grown via the NaCl/KCl flux method. The obtained lattice constant c of Ni0:05TaS2 is 1.1999 nm, which is significantly smaller than that of 2H-TaS2 (1.208 nm). Electrical resistivity and magnetization measurements reveal that the superconductivity transition temperature of Ni0:05TaS2 is enhanced from 0.8 K (2H-TaS2) to 3.9 K. The charge-density-wave transition of the matrix compound 2H-TaS2 is suppressed in Ni0:05TaS2. The success of Ni0:05TaS2 single crystal growth via a NaCl/KCl flux demonstrates that NaCl/KCl flux method will be a feasible method for single crystal growth of the layered transition metal dichalcogenides.Comment: 13pages, 6 figures, Published in SS

Co-existence of lung carcinoma metastasis and enchondroma in the femur of a patient with Ollier disease

Tumour-to-tumour metastasis is very unusual and has been defined as a tumour metastasis into another histologically different tumour. It is extremely rare in bone. We report a case of lung squamous cell carcinoma metastasized to an enchondroma in the femur of a patient with Ollier disease. A 60-year-old female had a history of a poorly differentiated squamous cell carcinoma of the lung. She underwent a video-assisted thoracoscopic lobectomy, and a follow-up MRI scan showed three lesions in the left distal femur and proximal tibia, which were initially interpreted as metastasis on radiology. Resection of the left proximal tibial lesion was performed, and the pathological findings were consistent with enchondroma with no evidence of metastasis. Subsequent curettage of lesions in the distal left femur revealed metastatic poorly differentiated carcinoma with foci of hyaline cartilage, which was most consistent with metastatic carcinoma in a pre-existing enchondroma. The MRI films were re-reviewed. Characteristic MRI features of enchondroma were found in the lesion in the left proximal tibia and one of the lesions in the left distal femur, while the features of the other lesion in the left distal femur included cortical destruction and extensive oedema in surrounding soft tissue, which were consistent with a malignant tumour. In addition, the enchondroma in the lateral condyle showed blurring and irregular inner margin and adjacent bone oedema, which likely represents a co-existing metastatic tumour and enchondroma. The difference in lineage was confirmed by immunohistochemistry. The final diagnosis was metastatic poorly differentiated carcinoma of the lung into a co-existent enchondroma. The diagnosis can be challenging and could be easily overlooked both radiologically and histologically. Thorough clinical and radiological information is critical for the diagnosis, and despite a very unusual event, awareness of the tumour-to-tumour metastasis phenomenon can avoid an inaccurate diagnosis by the pathologist, therefore preventing inappropriate clinical intervention

Mass measurements of neutron-deficient Y, Zr, and Nb isotopes and their impact on rp and νp nucleosynthesis processes

© 2018 The Authors. Published by Elsevier B.V. This manuscript is made available under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International licence (CC BY-NC-ND 4.0). For further details please see: https://creativecommons.org/licenses/by-nc-nd/4.0/Using isochronous mass spectrometry at the experimental storage ring CSRe in Lanzhou, the masses of 82Zr and 84Nb were measured for the first time with an uncertainty of ∼10 keV, and the masses of 79Y, 81Zr, and 83Nb were re-determined with a higher precision. The latter are significantly less bound than their literature values. Our new and accurate masses remove the irregularities of the mass surface in this region of the nuclear chart. Our results do not support the predicted island of pronounced low α separation energies for neutron-deficient Mo and Tc isotopes, making the formation of Zr–Nb cycle in the rp-process unlikely. The new proton separation energy of 83Nb was determined to be 490(400) keV smaller than that in the Atomic Mass Evaluation 2012. This partly removes the overproduction of the p-nucleus 84Sr relative to the neutron-deficient molybdenum isotopes in the previous νp-process simulations.Peer reviewe

Single crystal growth and characterizations of Cu0.03TaS2 superconductors

Single crystal of Cu0.03TaS2 with low copper intercalated content was successfully grown via chemical iodine-vapor transport. The structural characterization results show that the copper intercalated 2H-Cu0.03TaS2 single crystal has the same structure of the CdI2-type structure as the parent 2H-TaS2 crystal. Electrical resistivity and magnetization measurements reveal that 2H-Cu0.03TaS2 becomes a superconductor below 4.2 K. Besides, electrical resistivity and Hall effects results show that a charge density wave transition occurs at TCDW = 50 K.Comment: 14 pages, 6 figures,revised versio

Measurements of the observed cross sections for e+e−→e^+e^-\to exclusive light hadrons containing π0π0\pi^0\pi^0 at s=3.773\sqrt s= 3.773, 3.650 and 3.6648 GeV

By analyzing the data sets of 17.3, 6.5 and 1.0 pb$^{-1}$ taken, respectively, at $\sqrt s= 3.773$, 3.650 and 3.6648 GeV with the BES-II detector at the BEPC collider, we measure the observed cross sections for $e^+e^-\to \pi^+\pi^-\pi^0\pi^0$, $K^+K^-\pi^0\pi^0$, $2(\pi^+\pi^-\pi^0)$, $K^+K^-\pi^+\pi^-\pi^0\pi^0$ and $3(\pi^+\pi^-)\pi^0\pi^0$ at the three energy points. Based on these cross sections we set the upper limits on the observed cross sections and the branching fractions for $\psi(3770)$ decay into these final states at 90% C.L..Comment: 7 pages, 2 figure

Partial wave analysis of J/\psi \to \gamma \phi \phi

Using $5.8 \times 10^7 J/\psi$ events collected in the BESII detector, the radiative decay $J/\psi \to \gamma \phi \phi \to \gamma K^+ K^- K^0_S K^0_L$ is studied. The $\phi\phi$ invariant mass distribution exhibits a near-threshold enhancement that peaks around 2.24 GeV/$c^{2}$. A partial wave analysis shows that the structure is dominated by a $0^{-+}$ state ($\eta(2225)$) with a mass of $2.24^{+0.03}_{-0.02}{}^{+0.03}_{-0.02}$ GeV/$c^{2}$ and a width of $0.19 \pm 0.03^{+0.06}_{-0.04}$ GeV/$c^{2}$. The product branching fraction is: $Br(J/\psi \to \gamma \eta(2225))\cdot Br(\eta(2225)\to \phi\phi) = (4.4 \pm 0.4 \pm 0.8)\times 10^{-4}$.Comment: 11 pages, 4 figures. corrected proof for journa

Direct Measurements of Absolute Branching Fractions for D0 and D+ Inclusive Semimuonic Decays

By analyzing about 33 $\rm pb^{-1}$ data sample collected at and around 3.773 GeV with the BES-II detector at the BEPC collider, we directly measure the branching fractions for the neutral and charged $D$ inclusive semimuonic decays to be $BF(D^0 \to \mu^+ X) =(6.8\pm 1.5\pm 0.7)$ and $BF(D^+ \to \mu^+ X) =(17.6 \pm 2.7 \pm 1.8)$, and determine the ratio of the two branching fractions to be $\frac{BF(D^+ \to \mu^+ X)}{BF(D^0 \to \mu^+ X)}=2.59\pm 0.70 \pm 0.25$