3,513 research outputs found

    Study on the nonexistence of liquid miscibility gap in the Ce-Mn system

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    To ascertain whether the liquid miscibility gap exists in the Ce-Mn system, 3 key alloys are prepared by arc melting the pure elements, annealed at specified temperature for 20 minutes, quenched in ice water and then subjected to X-ray diffraction (XRD) analysis for phase identification and to scanning electron microscopy (SEM) with energy dispersive X-ray analysis for microstructure observation and composition analysis. The XRD examination indicated that terminal solutions based on Ce and Mn exist in the water-quenched alloys. No compound was detected. Microstructure observation and composition analysis indicate the nonexistence of the liquid miscibility gap. The newly assessed Ce-Mn phase diagram was presented.

    Expedited circular dichroism prediction and engineering in two-dimensional diffractive chiral metamaterials leveraging a powerful model-agnostic data enhancement algorithm

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    A model-agnostic data enhancement (MADE) algorithm is proposed to comprehensively investigate the circular dichroism (CD) properties in the higher-order diffracted patterns of two-dimensional (2D) chiral metamaterials possessing different parameters. A remarkable feature of MADE algorithm is that it leverages substantially less data from a target problem and some training data from another already solved topic to generate a domain adaptation dataset, which is then used for model training at no expense of abundant computational resources. Specifically, nine differently shaped 2D chiral metamaterials with different unit period and one special sample containing multiple chiral parameters are both studied utilizing the MADE algorithm where three machine learning models (i.e, artificial neural network, random forest regression, support vector regression) are applied. The conventional rigorous coupled wave analysis approach is adopted to capture CD responses of these metamaterials and then assist the training of MADE, while the additional training data are obtained from our previous work. Significant evaluations regarding optical chirality in 2D metamaterials possessing various shape, unit period, width, bridge length, and separation length are performed in a fast, accurate, and data-friendly manner. The MADE framework introduced in this work is extremely important for the large-scale, efficient design of 2D diffractive metamaterials and more advanced photonic devices

    Dynamics and stress in gravity driven granular flow

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    We study, using simulations, the steady-state flow of dry sand driven by gravity in two-dimensions. An investigation of the microscopic grain dynamics reveals that grains remain separated but with a power-law distribution of distances and times between collisions. While there are large random grain velocities, many of these fluctuations are correlated across the system and local rearrangements are very slow. Stresses in the system are almost entirely transfered by collisions and the structure of the stress tensor comes almost entirely from a bias in the directions in which collisions occur.Comment: 4 pages, 3 eps figures, RevTe

    Can Determination of Circulating Endothelial Cells and Serum Caspase-Cleaved CK18 Predict for Response and Survival in Patients with Advanced Non–Small-Cell Lung Cancer Receiving Endostatin and Paclitaxel–Carboplatin Chemotherapy? A Retrospective Study

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    Introduction:Early prediction of the efficacy of a combination of an antiangiogenic drug with cytotoxic chemotherapy is a significant challenge. In that regard, circulating endothelial cells (CECs) and cytokeratins (CKs) seem to reflect their roles in both tumor angiogenesis and tumor cell death.Methods:Patients with advanced, previously untreated non–small-cell lung cancer were randomly assigned to an endostatin treatment group (paclitaxel + carboplatin + endostatin) and a control group (paclitaxel + carboplatin + placebo). A total of 122 patients were evaluated, of whom 107 had measurements of blood CECs, CK8, caspase-cleaved CK18 (ccCK18), and uncleaved CK18 (CK18) before and at weeks 3 and 6 of treatment, respectively.Results:Higher baseline CECs in patients with a tumor response (partial remission + stable disease, p = 0.002 for the entire group; p = 0.000 for the treatment group) were observed. The number of CECs decreased significantly after endostatin treatment (p = 0.000), whereas CK levels increased. Increased levels of ccCK18 and CK18, but not CK8, reached significance (p = 0.001 and p = 0.048, respectively) when compared with the baseline. Tumor response showed a strong correlation with reduction of CECs (p = 0.000) and increase of ccCK18 (p = 0.040) after endostatin therapy. Cutoff values of changes of CECs and ccCK18 for prediction of survival were 0.58/μl and 19.6 ng/ml, respectively. Reduction of CECs and increase of ccCK18 significantly correlated with longer median survival (p = 0.013 and p = 0.016 for progression-free survival; p = 0.009 and p = 0.012 for overall survival, respectively).Conclusions:CECs and CKs could be biomarkers for selecting patients with non–small-cell lung cancer who will benefit from treatment with endostatin in combination with paclitaxel plus carboplatin

    New mechanism to cross the phantom divide

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    Recently, type Ia supernovae data appear to support a dark energy whose equation of state ww crosses -1, which is a much more amazing problem than the acceleration of the universe. We show that it is possible for the equation of state to cross the phantom divide by a scalar field in the gravity with an additional inverse power-law term of Ricci scalar in the Lagrangian. The necessary and sufficient condition for a universe in which the dark energy can cross the phantom divide is obtained. Some analytical solutions with w<−1w<-1 or w>−1w>-1 are obtained. A minimal coupled scalar with different potentials, including quadratic, cubic, quantic, exponential and logarithmic potentials are investigated via numerical methods, respectively. All these potentials lead to the crossing behavior. We show that it is a robust result which is hardly dependent on the concrete form of the potential of the scalar.Comment: 11 pages, 5 figs, v3: several references added, to match the published versio

    Strong tuning of Rashba spin orbit interaction in single InAs nanowires

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    A key concept in the emerging field of spintronics is the gate voltage or electric field control of spin precession via the effective magnetic field generated by the Rashba spin orbit interaction. Here, we demonstrate the generation and tuning of electric field induced Rashba spin orbit interaction in InAs nanowires where a strong electric field is created either by a double gate or a solid electrolyte surrounding gate. In particular, the electrolyte gating enables six-fold tuning of Rashba coefficient and nearly three orders of magnitude tuning of spin relaxation time within only 1 V of gate bias. Such a dramatic tuning of spin orbit interaction in nanowires may have implications in nanowire based spintronic devices.Comment: Nano Letters, in pres
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