Monte Carlo Hamiltonian

We suggest how to construct an effective low energy Hamiltonian via Monte Carlo starting from a given action. We test it by computing thermodynamical observables like average energy and specific heat for simple quantum systems.Comment: Contribution to Lattice'99 (Theoretical developments) Text (LaTeX file) + 2 figures (ps files

Characteristics of shunting effect in resistance spot welding in mild steel based on electrode displacement

Shunting effect of resistance spot welding is evaluated based on the electrode displacement signals. The shunted welds in mild steel with different weld spacing were produced. The results showed that the weld spacing and nugget diameter were polynomial-correlated, and the minimum welding spacing of 20 mm can be derived from the results. Both the peak value and gradient of electrode displacement in the weld stage indicated strong correlations with the nugget diameters of shunted welds. Additional shunt path was found to further aggregate the shunting, suggesting the decline in the values of profile features. Furthermore, it is found that the shunting effect led to the decline of the dynamic resistance curves, which is contradictive to the trends between acceptable-sized and undersized welds claimed based on the single weld study. The paper shows that electrode displacement curves of shunting can be incorporated into existing quality monitoring system.The financial support from the Australian Research Council (Grant No. LP130101001) is fully acknowledged

A method for measuring rotation of a thermal carbon nanomotor using centrifugal effect

A thermal nanomotor is relatively easy to fabricate and regulate as it contains just a few or even no accessory devices. Since the double-wall carbon nanotube (CNT)-based rotary nanomotor was established in a thermostat, assessment of the rotation of the rotor (inner tube) in the stator (outer tube) of the nanomotor has been critical, but remains challenging due to two factors: the small size of the rotor (only a few nanometers) and the high rotational frequency (»1 GHz). To measure the rotation of the nanomotor, in the present study, a probe test method is proposed. Briefly, the rotor is connected to an end-tube (CNT) through a graphene (GN) nanoribbon. As the CNT-probe is on the trajectory of the end-tube which rotates with the rotor, it will collide with the end-tube. The sharp fluctuation indicating the probe tip deflection can be observed and recorded. As a curly GN by hydrogenation is adopted for connecting the rotor and the end-tube, collision between the end-tube and the probe tip occurs only when the centrifugal force is higher than a threshold which can be considered as the rotational frequency of the rotor being measured by the present method.The authors are grateful for financial support from the National Natural-Science-Foundation of China (Grant No. 11372100) and the Australian Research Council (Grant No. DP140103137)

Laser Ablation Applications in Ablation-Resistance Characterization of Materials

Owing to the rapid heating and large power intensity, the laser beams were successfully used to characterize the ablation-resistant performance of materials, which provided us more knowledge about the usability of materials in the ablation environment and developing protection against laser irradiation. In this chapter, we comparatively introduced some experimental methods for ablation-resistance characterization of materials. The fundamentals of laser-material interactions were discussed from the physical and chemical aspects to help understand the laser ablation mechanism. Finally, we presented some practical applications of laser ablation in ablation-resistance characterization of ultra-high-temperature ceramics (UHTCs) and ceramic matrix composites and discussed the laser ablation behavior and mechanism

Effect of infiltration time on the microstructure and mechanical properties of C/C-SiC composite prepared by Si‐Zr10 alloyed melt infiltration

Low cost C/C-SiC composites were prepared through reactive melt infiltration with Si-Zr10 alloy infiltrant under different infiltration time. Effect of infiltration time on the microstructure and mechanical properties of the composite were investigated. ZrC tended to be formed in the composite and the amount of carbon phase decreased with an extension in the infiltration time according to the X-ray diffraction results. Phase transformation of the C/C-SiC composite was analyzed based on C-Si-Zr phase diagram. Flexural strength of the composite prepared by preform 0.9 g/cm³ decreased with an increase in the infiltration time while that of the composite prepared by preform 1.38 g/cm³ increased initially and then decreased reversely. The highest flexural strength of the composite was found at about 324 MPa. Flexural strength of the composite is considered to depend on its phase composition and fiber-matrix interface.This work was supported by National Natural Science Foundation of China (51302315), Innovation Foundation for Excellent Postgraduate of National University of Defense Technology and Hunan Provincial Innovation Foundation for Postgraduate. Yonggang Tong also thanks the support from China Scholarship Council

Laser ablation resistance and mechanism of Si-Zr alloyed melt infiltrated C/C-SiC composite

Ablation resistance of C/C-SiC composite prepared via Si-Zr alloyed reactive melt infiltration was evaluated using a facile and economical laser ablation method. Linear ablation rates of the composite increased with an increase in laser power densities and decreased with extended ablation time. The C/C-SiC composite prepared via Si-Zr alloyed melt infiltration presented much better ablation resistance compared with the C/SiC composite prepared by polymer infiltration and pyrolysis process. The good ablation resistance of the composite was attributed to the melted ZrC layer formed at the ablation center region. Microstructure and phase composition of different ablated region were investigated by SEM and EDS, and a laser ablation model was finally proposed based on the testing results and microstructure characterization. Laser ablation of the composite experienced three distinct periods. At the very beginning, the laser ablation was dominated by the oxidation process. Then for the second period, the laser ablation was dominated by the evaporation, decomposition and sublimation process. With the further ablation of the composite, chemical stable ZrC was formed on the ablated surface and the laser ablation was synergistically controlled by the scouring away of ZrC melts and evaporation, decomposition and sublimation process.This work is supported by National Natural Science Foundation of China (51641502)

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

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

Phase diagram of a Bose-Fermi mixture in a one-dimensional optical lattice in terms of fidelity and entanglement

We study the ground-state phase diagram of a Bose-Fermi mixture loaded in a one-dimensional optical lattice by computing the ground-state fidelity and quantum entanglement. We find that the fidelity is able to signal quantum phase transitions between the Luttinger liquid phase, the density-wave phase, and the phase separation state of the system; and the concurrence can be used to signal the transition between the density-wave phase and the Ising phase.Comment: 4 pages 3 figure

Versatile Roles of V-ATPases Accessory Subunit Ac45 in Osteoclast Formation and Function

Vacuolar-type H+-ATPases (V-ATPases) are macromolecular proton pumps that acidify intracellular cargos and deliver protons across the plasma membrane of a variety of specialized cells, including bone-resorbing osteoclasts. Extracellular acidification is crucial for osteoclastic bone resorption, a process that initiates the dissolution of mineralized bone matrix. While the importance of V-ATPases in osteoclastic resorptive function is well-defined, whether V-ATPases facilitate additional aspects of osteoclast function and/or formation remains largely obscure. Here we report that the V-ATPase accessory subunit Ac45 participates in both osteoclast formation and function. Using a siRNA-based approach, we show that targeted suppression of Ac45 impairs intracellular acidification and endocytosis, both are prerequisite for osteoclastic bone resorptive function in vitro. Interestingly, we find that knockdown of Ac45 also attenuates osteoclastogenesis owing to a reduced fusion capacity of osteoclastic precursor cells. Finally, in an effort to gain more detailed insights into the functional role of Ac45 in osteoclasts, we attempted to generate osteoclast-specific Ac45 conditional knockout mice using a Cathepsin K-Cre-LoxP system. Surprisingly, however, insertion of the neomycin cassette in the Ac45-FloxNeo mice resulted in marked disturbances in CNS development and ensuing embryonic lethality thus precluding functional assessment of Ac45 in osteoclasts and peripheral bone tissues. Based on these unexpected findings we propose that, in addition to its canonical function in V-ATPase-mediated acidification, Ac45 plays versatile roles during osteoclast formation and function