Design and automated operation of a condensation-induced depressurization system

Typical examples of the use of the vacuum environments in industry include vacuum coating, vacuum drying, vacuum packing, vacuum casting, vacuum heat treatment, vacuum cooling for food storage and leakage detection. Most of these applications require a comparatively small volume of vacuum environment. However, there are also many applications where enormous vacuum chambers are needed. For example, a large vacuum chamber is used to simulate the conditions of space. This study investigates the design and the automated operation of a vacuum generation system based on the idea of the condensation-induced depressurization with prefilled condensable medium in a confined, adiabatic chamber. The operation process of this new system includes mainly four phases, steam filling phase, cooling phase, usage phase and transition phase, operating sequentially. An automated control system based on these phases is designed and implemented on a laboratory scaled experimental system. This experimental system serves as a vacuum environment application to demonstrate the automatic and continuous operation of the condensation-induced depressurization system. In order to obtain a better understanding on the selection of parameters for performance improvement, models of the first three process phases are developed and analyzed. These models provide a reference for the design of systems for other industry applications as well. Methods of improving the system design and operation are investigated. The analysis shows that high pressure and fast flow steam source will accelerate the steam filling process. Removal of the transition phase improves the steam filling phase and speeds up the vacuum preparation. Improvement can also be achieved on the coordination between vacuum generation and usage through control elements, as well as the proper selection of volume ratio between usage chamber and preparation chambers. The ultimate objective of this study is that the results can be used to develop guidelines for the design and operation of vacuum generation systems according to specific usage patterns of the vacuum environment applications

Tuning Strain in Flexible Graphene Nanoelectromechanical Resonators

The structural flexibility of low dimensional nanomaterials offers unique opportunities for studying the impact of strain on their physical properties and for developing innovative devices utilizing strain engineering. A key towards such goals is a device platform which allows the independent tuning and reliable calibration of the strain. Here we report the fabrication and characterization of graphene nanoelectromechanical resonators(GNEMRs) on flexible substrates. Combining substrate bending and electrostatic gating, we achieve the independent tuning of the strain and sagging in graphene and explore the nonlinear dynamics over a wide parameter space. Analytical and numerical studies of a continuum mechanics model, including the competing higher order nonlinear terms, reveal a comprehensive nonlinear dynamics phase diagram, which quantitatively explains the complex behaviors of GNEMRs

Amplifying Frequency Up-Converted Infrared Signals with a Molecular Optomechanical Cavity

Frequency up-conversion, enabled by molecular optomechanical coupling, has recently emerged as a promising approach for converting infrared signals into the visible range through quantum coherent conversion of signals. However, detecting these converted signals poses a significant challenge due to their inherently weak signal intensity. In this work, we propose an amplification mechanism capable of enhancing the signal intensity by a factor of 1000 or more in a molecular-cavity system consisting $10^{7}$ molecules. The mechanism takes advantage of the strong coupling enhancement with molecular collective mode and Stokes sideband pump. Our work demonstrates a feasible approach for up-converting infrared signals to the visible range.Comment: 5 pages, 4 figures for the main text; 6 pages, 2 figures for Supplementary Materia

Dibromidobis(1,10-phenanthroline-κ2 N,N′)cadmium(II)

The title compound, [CdBr2(C12H8N2)2], synthesized by the hydro­thermal reaction of Cd(CH3COO)2·2H2O with NaBr and 1,10-phenanthroline, has the CdII cation coordinated by two Br− anions and four N atoms from two 1,10-phenanthroline ligands in a distorted octa­hedral geometry. The crystal packing is stabilized by inter­molecular π–π inter­actions with centroid–centroid distances 3.572 (1) and 3.671 (1) Å together with C—H⋯Br hydrogen bonds

BCL9 enhances the development of cervical carcinoma by deactivating CPEB3/EGFR axis

Purpose: To investigate the differential expression of BCL9 in cervical carcinoma samples, analyze its biological functions in regulating malignant phenotypes of cervical carcinoma cells, and to explore its potential molecular mechanism.Methods: Expression levels of BCL9 in 58 pairs of cervical carcinoma tissues and paracancerous tissues were determined using quantitative real time-polymerase chain reaction (qRT-PCR). Kaplan- Meier curves were used to analyze the prognostic potential of BCL9 in cervical carcinoma. After knockdown using BCL9 by lentivirus transfection, proliferative and migratory changes in Siha and HeLa cells were determined by CCK-8, colony formation and Transwell assays. Cytoplasmic polyadenylation element binding protein 3 (CPEB3), the potential downstream target of BCL9, was confirmed via dualluciferase reporter assay. Western blot analyses were conducted to determine the protein levels of CPEB3, EGFR, AKT and p21 in Siha and HeLa cells with BCL9 knockdown. The co-regulation of BCL9 and CPEB3 on phenotypes of cervical carcinoma cell was investigated.Results: BCL9 was upregulated in cervical carcinoma tissues. The high level of BCL9 was predicted by the tumor size, advanced stage and poor prognosis. The knockdown of BCL9 significantly weakened proliferative and migratory abilities of Siha and HeLa cells (p < 0.05). CPEB3 was the downstream target of BCL9, and was lowly expressed in cervical carcinoma tissues. The knockdown of BCL9 upregulated CPEB3, and downregulated EGFR, AKT and p21 (p < 0.05). The knockdown of CPEB3 also reversed the influence of silenced BCL9 in regulating its proliferative and migratory abilities in cervical carcinoma cells (p < 0.05).Conclusion: BCL9 drives the deterioration of cervical carcinoma by inhibiting the CPEB3/EGFR axis.Thus, BCL9 may be a novel molecular target for cervical carcinoma treatment

The Roles of PI3K/AKT/mTOR and MAPK/ERK Signaling Pathways in Human Pheochromocytomas

Objectives. The roles of PI3K/AKT/mTOR and MAPK/ERK pathways involved in the pathogenesis of pheochromocytoma and paraganglioma (PPGL) were demonstrated mostly by in vitro studies with rat or mouse cells and were mainly studied at transcriptional level. This study aimed to investigate the effect of these pathways on the proliferation of human PPGL cells and the activation of these pathways in PPGLs. Methods. Human PPGL cells were treated with sunitinib and inhibitors of PI3K (LY294002), MEK1/2 (U0126), and mTORC1/2 (AZD8055). Cell proliferation was detected by MTT assay. Protein phosphorylation was detected by Western blotting. Results. In most PPGLs, AKT, ERK1/2, and mTOR were activated. LY294002 (10 μM), U0126 (10 μM), AZD8055 (1 μM), and sunitinib (1 μM) inhibited PPGL cell proliferation in ten primary cultures of tissues, including four from patients with gene mutations. MEK1/2 inhibitor decreased mTOR phosphorylation. Inhibition of mTOR reduced phosphorylation of AKT and ERK1/2. Sunitinib inhibited phospho-ERK1/2 and phospho-mTOR. Conclusion. Our study suggested that PI3K/AKT/mTOR and MAPK/ERK signaling pathways play vital roles in human PPGL and are activated in most PPGLs. Inhibiting multiple pathways might be a novel therapeutic approach for PPGLs

Anisotropic transport for ν=2/5\nu=2/5 FQH state at intermediate magnetic field

The $\nu=2/5$ state is spin-unpolarized at weak magnetic field and fully polarized at strong field. At intermediate field, a plateau of half the maximal polarization is observed. We study this phenomenon in the frame of composite fermion theory. Due to the mixing of the composite fermion Landau levels, the unidirectional charge/spin density wave state of composite fermions is lower in energy than the Wigner crystal. It means that transport anisotropy, similar to those for electrons in higher Landau levels at half fillings, may take place at this fractional quantum Hall state when the external magnetic field is in an appropriate range. When the magnetic field is tilted an angle, the easy transport direction is perpendicular to the direction of the in-plane field. Varying the partial filling factor of composite fermion Landau level from 0 to 1, we find that the energy minimum occurs in the vicinity of one-half.Comment: 2 figure

Learning and Controlling Network Diffusion in Dependent Cascade Models

Abstract—Diffusion processes have increasingly been used to represent flow of ideas, traffic and diseases in networks. Learning and controlling the diffusion dynamics through management actions has been studied extensively in the context of independent cascade models, where diffusion on outgoing edges from a node are independent of each other. Our work, in contrast, addresses (a) learning diffusion dynamics parameters and (b) taking management actions to alter the diffusion dynamics to achieve a desired outcome in dependent cascade models. A key characteristic of such dependent cascade models is the flow preservation at all nodes in the network. For example, traffic and people flow is preserved at each network node. As a case study, we address learning visitor mobility pattern at a theme park based on observed historical wait times at individual attractions, and use the learned model to plan management actions that reduce wait time at attractions. We test on real-world data from a theme park in Singapore and show that our learning approach can achieve an accuracy close to 80 % for popular attractions, and the decision support algorithm can provide about 10-20 % reduction in wait time. I