Heat Pipe and Phase Change Heat Transfer Technologies for Electronics Cooling

The heat pipe is a well-known cooling module for advanced electronic devices. The heat pipe has many applications, particularly in electronics and related area such as PC, laptop, display, artificial satellite, and telecommunication modules. The heat pipe utilizes phase change heat transfer inside enveloped structures, where the working fluid evaporates in heated zone, and vapor moves to the condenser, and the condensed liquid is pumped back through microporous structure call wick. The performance of applicability in electronics of heat pipe is strongly dependent on the geometry, working fluid, and microstructure of wick. Therefore, it is worth considering the theory and technologies related to heat pipes for advanced electronics cooling. According to the purpose of this chapter mentioned above, the author considers fundamental aspects regarding heat pipe and phase change phenomena. First, the working principle of heat pipe is introduced. Important parameters in heat pipe are considered, and theoretical model for predicting the thermal performance of the heat pipe is introduced. In addition, design method for heat pipe is presented. Finally, applications of heat pipe to electronics cooling are presented. This chapter covers knowledge and state-of-art technologies in regard to heat pipe and phase change heat transfer. For a reliable operation of future electronics that have ultra-high heat flux amounts to 1000 W/m2, heat pipe and phase change heat transfer are essential. This chapter provides the most valuable opportunity for all readers from industry and academia to share the professional knowledge and to promote their ability in practical applications

Molybdenum Disulfide-Based Photocatalysis:Bulk-to-Single Layer Structure and Related Photomechansim for Environmental Applications

Bulk-to-single layer molybdenum disulfide (MoS2) is widely used as a robust candidate for photodegradation of organic pollutants, hydrogen production, and CO2 reduction. This material features active edge sites and narrow band gap features, which are useful for generating reactive species in aqueous suspensions. However, the high-charge carrier recombination, photocorrosion, unstable sulfide state, and formation of Mo-S-O links during photocatalytic reactions limit its applicability. Thus, research has focused on improving the performance of MoS2 by tailoring its bulk-to-single layer structure and combining it with other semiconductor materials to improve the photocatalytic performance. Different strategies have been successfully applied to enhance the photocatalytic activity of MoS2, including tailoring of the surface morphology, formation of heterojunctions with other semiconductors, doping, and modification with excess sulfur or carbon nanostructures. This review describes the influence of starting precursors, sulfur sources, and synthetic methods to obtain heterostructured morphologies and study their impact on the photocatalytic efficiency. Finally, the relevance of crystal facets and defects in photocatalysis is outlined. Future applications of MoS2 with tailoring and tuning physicochemical properties are highlighted

Visible-Light-Driven Photocatalytic Activity of SnO2-ZnO Quantum Dots Anchored on g-C3N4 Nanosheets for Photocatalytic Pollutant Degradation and H-2 Production

A zero-dimensional/two-dimensional heterostructure consists of binary SnO2-ZnO quantum dots (QDs) deposited on the surface of graphitic carbon nitride (g-C3N4) nanosheets. The so-called SnO2-ZnO QDs/g-C3N4 hybrid was successfully synthesized via an in situ co-pyrolysis approach to achieve efficient photoactivity for the degradation of pollutants and production of hydrogen (H-2) under visible-light irradiation. High-resolution transmission electron microscopy images show the close contacts between SnO2-ZnO QDs with the g-C3N4 in the ternary SnO2-ZnO QDs/g-C3N4 hybrid. The optimized hybrid shows excellent photocatalytic efficiency, achieving 99% rhodamine B dye degradation in 60 min under visible-light irradiation. The enriched charge-carrier separation and transportation in the SnO2-ZnO QDs/g-C3N4 hybrid was determined based on electrochemical impedance and photocurrent analyses. This remarkable photoactivity is ascribed to the "smart" heterostructure, which yields numerous benefits, such as visible-light-driven fast electron and hole transfer, due to the strong interaction between the SnO2-ZnO QDs with the g-C3N4 matrix. In addition, the SnO2-ZnO QDs/g-C3N4 hybrid demonstrated a high rate of hydrogen production (13 673.61 mu mol g(-1)), which is 1.06 and 2.27 times higher than that of the binary ZnO/g-C3N4 hybrid (12 785.54 mu mol g(-1)) and pristine g-C3N4 photocatalyst (6017.72 mu mol g(-1)). The synergistic effect of increased visible absorption and diminished recombination results in enhanced performance of the as-synthesized tin oxide-and zinc oxide-modified g-C3N4. We conclude that the present ternary SnO2-ZnO QDs/g-C3N4 hybrid is a promising electrode material for H-2 production and photoelectrochemical cells

Tiny MoO3 nanocrystals self-assembled on folded molybdenum disulfide nanosheets via a hydrothermal method for supercapacitor

Coupling of two active semiconductors can easily lead to a deterioration of their intrinsic properties. In this work, tiny MoO3 nanocrystals were deposited on 3D MoS2 frameworks via a hydrothermal reaction, with heterostructures forming by oxygen-bonding interactions at their interface. When tested as a supercapacitor electrode, the MoS2/MoO3 heterostructure exhibited a high specific capacitance of 287.7 F g(-1) at a current density of 1 A g(-1), and a remarkable cycling stability after 1000 cycles at 1 A g(-1) in an aqueous solution compared to pristine MoS2. The results thus reveal the superior properties of the MoS2/MoO3 heterostructure for supercapacitor electrode

The Optimal Approach for Laparoscopic Adrenalectomy through Mono Port regarding Left or Right Sides: A Comparative Study

Introduction. Several studies have shown the feasibility and safety of both transperitoneal and posterior retroperitoneal approaches for single incision laparoscopic adrenalectomy, but none have compared the outcomes according to the left- or right-sided location of the adrenal glands. Materials and Methods. From 2009 to 2013, 89 patients who received LAMP (laparoscopic adrenalectomy through mono port) were analyzed. The surgical outcomes attained using the transperitoneal approach (TPA) and posterior retroperitoneal approach (PRA) were analyzed and compared. Results and Discussion. On the right side, no significant differences were found between the LAMP-TPA and LAMP-PRA groups in terms of patient characteristics and clinicopathological data. However, outcomes differed in which LAMP-PRA group had a statistically significant shorter mean operative time (84.13 ± 41.47 min versus 116.84 ± 33.17 min; P=0.038), time of first oral intake (1.00 ± 0.00 days versus 1.21 ± 0.42 days; P=0.042), and length of hospitalization (2.17 ± 0.389 days versus 3.68 ± 1.38 days; P≤0.001), whereas in left-sided adrenalectomies LAMP-TPA had a statistically significant shorter mean operative time (83.85 ± 27.72 min versus 110.95 ± 29.31 min; P=0.002). Conclusions. We report that LAMP-PRA is more appropriate for right-sided laparoscopic adrenalectomies due to anatomical characteristics and better surgical outcomes. For left-sided laparoscopic adrenalectomies, however, we propose LAMP-TPA as a more suitable method

Double Diffraction Dissociation at the Fermilab Tevatron Collider

We present results from a measurement of double diffraction dissociation in $\bar pp$ collisions at the Fermilab Tevatron collider. The production cross section for events with a central pseudorapidity gap of width $\Delta\eta^0>3$ (overlapping $\eta=0$) is found to be $4.43\pm 0.02{(stat)}{\pm 1.18}{(syst) mb}$ [$3.42\pm 0.01{(stat)}{\pm 1.09}{(syst) mb}$] at $\sqrt{s}=1800$ [630] GeV. Our results are compared with previous measurements and with predictions based on Regge theory and factorization.Comment: 10 pages, 4 figures, using RevTeX. Submitted to Physical Review Letter

A Measurement of the Differential Dijet Mass Cross Section in p-pbar Collisions at sqrt{s}=1.8 TeV

We present a measurement of the cross section for production of two or more jets as a function of dijet mass, based on an integrated luminosity of 86 pb^-1 collected with the Collider Detector at Fermilab. Our dijet mass spectrum is described within errors by next-to-leading order QCD predictions using CTEQ4HJ parton distributions, and is in good agreement with a similar measurement from the D0 experiment.Comment: 18 pages including 2 figures and 3 tables. Submitted to Phys. Rev. D Rapid Communication

Search for New Particles Decaying to top-antitop in proton-antiproton collisions at squareroot(s)=1.8 TeV

We use 106 \ipb of data collected with the Collider Detector at Fermilab to search for narrow-width, vector particles decaying to a top and an anti-top quark. Model independent upper limits on the cross section for narrow, vector resonances decaying to \ttbar are presented. At the 95% confidence level, we exclude the existence of a leptophobic \zpr boson in a model of topcolor-assisted technicolor with mass M_{\zpr} $<$ 480 \gev for natural width $\Gamma$ = 0.012 M_{\zpr}, and M_{\zpr} $<$ 780 \gev for $\Gamma$ = 0.04 M_{\zpr}.Comment: The CDF Collaboration, submitted to PRL 25-Feb-200

Search for Narrow Diphoton Resonances and for gamma-gamma+W/Z Signatures in p\bar p Collisions at sqrt(s)=1.8 TeV

We present results of searches for diphoton resonances produced both inclusively and also in association with a vector boson (W or Z) using 100 pb^{-1} of p\bar p collisions using the CDF detector. We set upper limits on the product of cross section times branching ratio for both p\bar p\to\gamma\gamma + X and p\bar p\to\gamma\gamma + W/Z. Comparing the inclusive production to the expectations from heavy sgoldstinos we derive limits on the supersymmetry-breaking scale sqrt{F} in the TeV range, depending on the sgoldstino mass and the choice of other parameters. Also, using a NLO prediction for the associated production of a Higgs boson with a W or Z boson, we set an upper limit on the branching ratio for H\to\gamma\gamma. Finally, we set a lower limit on the mass of a `bosophilic' Higgs boson (e.g. one which couples only to \gamma, W, and Z$ bosons with standard model couplings) of 82 GeV/c^2 at 95% confidence level.Comment: 30 pages, 11 figure