Can Metal Matrix‐Hydrophobic Nanoparticle Composites Enhance Water Condensation by Promoting the Dropwise Mode?

Incorporation of condensers treated with hydrophobic modifiers that promote the efficient dropwise condensation mode can significantly enhance the performance of power generation and desalination plants. However, this approach is not used in industry because of low thermal conductivity and limited durability of the thin hydrophobic coatings. Here, it is argued that metal matrix hydrophobic nanoparticle composites can be a robust and high thermal conductivity alternative to hydrophobic polymeric and ceramic thin films. By characterizing condensation on a wide range of mimicked composite surfaces, it is demonstrated that to promote dropwise condensation the filler nanoparticles must have size and spacing significantly smaller than the few micrometer average center‐to‐center separation distance between closest neighboring droplets prior to onset of the coalescence dominated growth stage. Furthermore, the nanoparticle density does not have to be high enough to make the surface hydrophobic, but only sufficiently high to reduce the contact angle hysteresis, and with that pinning of droplets during coalescence and gravity assisted shedding. Using experimental results in conjunction with condensation models, it is estimated that a substantial heat transfer enhancement can be achieved via promotion of sustained dropwise mode even by using copper and aluminum matrix composites fully loaded with polytetrafluoroethylene nanoparticles if the film thickness is below ≈0.5 mm.     

The TDCPR Management Mode of Engineering Equipment

The Three Gorges Project is a very large project,and its structure is very complex.Interna-tional advanced engineering equipment is broadly used.The state of equipment running directly influ-ences project building qualities and limited time.According to the factud conditions of the Three Gor-ges Project,the characteristics of engineering equipment are analyzed.At the same time ,some theories about equipment management are induced ,and the TDCPR management mode of engineering equip-ment of the Three Gorges Project is put forwared in order to gain the aim of managing and using equip-ment well and speeding up the project construction.     

Relevance of the Phonon-Coupling Mode on the Superconducting Pairing Interaction of La<Subscript>2−<Emphasis Type="Italic">x</Emphasis></Subscript>Sr<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>CuO<Subscript>4</Subscript>

Despite the intensive efforts for determining the mechanism that causes high-temperature superconductivity in copper oxide materials (cuprates), no consensus on the pairing mechanism has been reached. Recent advances in angle-resolved photoemission spectroscopies (ARPES) have suggested that a sizeable electron–phonon coupling exists as the principal cause for kinks in the dispersion relations (energy versus wavevector) of the electronic states. Here, we report on a systematic study of the influence of the electron–phonon-coupling parameter “λ” in the electronic quasiparticle dispersions along the nodal direction for La_2−x Sr _x CuO₄, covering the entire doping range over which the electron transport properties vary from insulating (0≲x≲0.03) to superconducting (0.05≲x≲0.25) and eventually non-superconducting metal (x>0.25). This includes our recently introduced theoretical model to adjust the experimental data on the fermionic band dispersion. The coupling constant λ, calculated consistently with the nodal kink dispersions, reproduces the observed critical temperatures T _c , the gap ratio 2Δ ₀/k _B T _c , and other parameters which have been studied from several equations. Our results suggest that, at least in La_2−x Sr _x CuO₄, electron–phonon coupling is the most relevant boson-coupling mode to influence the electron dynamics, and must therefore be included in any microscopic theory of superconductivity.     

Research on Metal′s Fretting Oxidation Mode

1Introduction Frettingdamageoccursbetweenseveralcontactingbodiessubjectedtobulkfatiguestresswithcon tactpressure.Itcanreducestrengthandlifeofengineeringstructuresandmachineparts.Sofar,manyresearchershavecompletedmanyworksonfrettingmechanismsandpresentedseveralfretting mapsofit.Forexample,asshowninFigure1andFigure2,Frenchscholar,Vingsbo[1],presented twokindsoffrettingmechanismsmaps,i.e.workingconditionfrettingmapandmaterialfretting map.Basedonthemaps,therelationshipbetweentheworkingconditionp…     

Research on Metal＇s Fretting Oxidation Mode

Fretting oxidization is a main form of fretting chemical damage. In this paper, a theory analysis was proceeded for several key factors affecting this damage and one kind of fretting map based on the co-effect of those key factors were presented. By the map, not only the mode of fretting oxide can be learned better, but also it is possible to reduce fretting damage through changing working and material parameters reasonably.     

Applying Network Technology to Improve TV News Production Mode

1　IntroductionNewsproductionisthecorebusinessofTVstation,whichhasanimportantinfluenceonaudienceratingofTVstation.Withthedevelopmentofinformationtechnology,traditionalTVnewsproductionmode(TVNPM)facesgreatchallenge.Itiswellknownthattraditionalnewsprogramsarecompletedfullybyhand,whichmakestheproductioncyclelongerandalsorequiresharmonyamongdifferentdepartments.Allthesecanbetteradapttothedevelopmentofinformationage,andthedevelopmentindatabasetechnologyandnetworktechnologybringsforwardhigherde…     

Mixed‐Mode Stress Intensity Factors for Partially Opened Cracks

Failure considerations under mixed-mode loading require knowledge about the influence of friction between partially closed crack faces in the case of a negative mode-I stress intensity factor. A simple relation is derived, which allowes to compute friction contributions to the mode-II stress intensity factor K_II for the case of negative mode-I stress intensity factors K_I. The relation is exact for the limit case of an edge crack in a half-space. It can be shown that small cracks in finite bodies can also be described with sufficient accuracy.     

Fracture Process in ± θ Laminates Subjected to Mode II Loading

This work studies the behavior of a multidirectional laminate under Mode II loading. We describe the process of delamination in a reinforced composite of glass/epoxy. The stacking sequence (plies orientation [± ] was selected to minimize the coupling effects. The Mode II interlaminar test under three-point bending and cantilever flexure using ENF (End Notch Flexure) and ELS (End Load Split) specimens, respectively, was performed and analyzed. The test procedures and the results of strain-energy-release rate study for crack initiation are presented. The fracture process and the mechanical behavior of the two types of specimens are analyzed. The analysis clearly shows a close link between the angle , the ratio a/L, and the thickness h of the specimen. Fracture by delamination can be obtained only with an optimal choice of these parameters. The analysis of the states of stresses at the tip of crack allows us to explain the phenomenon of bifurcation between plies and is confirmed by the experimental results.     

A Novel Sliding Mode Variable Structure Controller Based on a Genetic Algorithm

A novel control method has been proposed by using the genetic algorithm （GA） for nonlinear and complex plants. The proposed control strategy is based on a variable structure control, it overcomes the defects of other adaptive methods such as strong dependence to the system. A GA is used to learn to optimally select integral coefficient C. Simulation results verified the effectiveness of the controller. For position control of Direct Current （DC） motor in practice, this method has good performance and strong robustness, and both dynamic and steady performances were improved.     

Variable—Range hopping in Fe<Subscript>2</Subscript>O<Subscript>3</Subscript>-Bi<Subscript>2</Subscript>O<Subscript>3</Subscript>-K<Subscript>2</Subscript>B<Subscript>4</Subscript>O<Subscript>7</Subscript> glasses

The dc conductivity of the glasses in the Fe₂O₃-Bi₂O₃-K₂B₄O₇ system was studied at temperatures between 223 and 393 K. At temperatures from 300 to 223 K, T^–1/4 (T is temperature) dependence of the conductivity was found, however, both Mott variable-range hopping and Greaves intermediate range hopping models are found to be applicable. Mott and Greaves parameters analysis gave the density of states at Fermi level N (E_F) = 3.13 × 10²⁰–21.01 × 10²⁰ and 1.93 × 10²¹–16.39 × 10²¹ cm^–3eV^–1 at 240 K, respectively. The variable-range hopping conduction occurred in the temperature range T = 300–223 K, since W_D was found to be large (W_D = 0.08–0.14 eV for these glasses) and dominated the conduction at T < 300 K.     

&lt;&lt;标准化法&gt;&gt;应是一部可以操作的法律

《中华人民共和国标准化法》是1988年12月29日第七届全国人大常委会第五次会议正式通过的,1990年4月6日国务院第53号令批准发布了《中华人民共和国标准化法实施条例》,该法及其实施条例的颁布实施,对于发展社会主义市场经济,促进技术进步,改进产品质量,提高社会经济效益,维护国家和人民的利益,发挥了重要的作用。但是,随着社会主义市场经济的不断发展,《标准化法》及其实施条例已难以适应新形势的需要,应予以修订。(一)《标准化法》只规定相应的“法律责任”,而没有具体的罚则,在执法中难以操作。执法人员对于违反《标准化法》的行为,都是依…     

Microstructure and properties of the Ba<Subscript>0.75−x</Subscript>Ca<Subscript>x</Subscript>La<Subscript>0.25</Subscript>Fe<Subscript>11.6</Subscript>Co<Subscript>0.25</Subscript>Ti<Subscript>0.15</Subscript>O<Subscript>19</Subscript> hexaferrites

In the case of Ti⁴⁺ remain unchanged, the Ca²⁺ substituted Ba_0.75?xCa_xLa_0.25Fe_11.6Co_0.25Ti_0.15O₁₉ (0?≤?x?≤?0.05) were prepared by conventional solid-state reaction method at temperature of 1280 °C. A ball-to-power weight ratio of 10:1. Their crystal structure and magnetic properties were mainly investigated. The results show that the single magnetoplumbite phase structure transformed into the multiphase structure. Meanwhile, the small amount of α-Fe₂O₃ phase existed in M-type phase. The micrographs were observed by a field emission scanning electron microscopy (SEM). Vibrating sample magnetometer (VSM) was used to analyze the magnetic properties. The saturation magnetization (M _s ) first increases then decreases when x from 0 to 0.03. But, when x from 0.03 to 0.05, the saturation magnetization (M _s ) first increases then decreases too. The maximum value is at x?=?0.04 (M _s ?=?70.73 emu/g). The value of coercivity (H _c ) first increases then decreases when x from 0 to 0.04. But, the value increased when x from 0.04 to 0.05. The maximum value is at x?=?0.02 (H _c ?=?1691 Oe).     

Phase equilibria in the Tl<Subscript>5</Subscript>Te<Subscript>3</Subscript>–Tl<Subscript>9</Subscript>BiTe<Subscript>6</Subscript>–Tl<Subscript>9</Subscript>TbTe<Subscript>6</Subscript> system

Phase equilibria in the Tl₅Te₃–Tl₉BiTe₆–Tl₉TbTe₆ system have been studied using differential thermal analysis, X-ray diffraction, and microhardness measurements. We have mapped out a number of vertical sections, the 760-K isothermal section of its phase diagram, and projections of its liquidus and solidus surfaces. The composition dependences of lattice parameters and microhardness have been obtained. The system has been shown to contain a continuous series of solid solutions, which crystallize in a tetragonal structure (Tl₅Te₃ type, sp. gr. I4/mcm).     

Phase equilibria in the system “CaAl<Subscript>2</Subscript>Si<Subscript>3</Subscript>O<Subscript>10</Subscript>”-Na<Subscript>2</Subscript>Al<Subscript>2</Subscript>Si<Subscript>3</Subscript>O<Subscript>10</Subscript>-H<Subscript>2</Subscript>O

The phase equilibria in the “CaAl₂Si₃O₁₀”-Na₂Al₂Si₃O₁₀-H₂O system are analyzed using structural and thermal analysis data, and the ideal gonnardite structure is modeled. The results suggest that, to ensure a better correlation with the structures of the zeolites in this series, a new structural model of the gonnardite-based solid solution must be selected, with the structure rotated through 45° about the c axis in the ab plane.     

Enhanced microwave dielectric properties of Ba<Subscript>0.40</Subscript>Sr<Subscript>0.60</Subscript>TiO<Subscript>3</Subscript>–Zr<Subscript>0.80</Subscript>Sn<Subscript>0.20</Subscript>TiO<Subscript>4</Subscript> composite ceramics

The (1−x) Ba_0.40Sr_0.60TiO₃ (BST)−xZr_0.80Sn_0.20TiO₄ (ZST) composite ceramics with x = 10, 20, 30, and 40 wt% were fabricated by conventional solid-state reaction method. With increasing of ZST content, the dielectric constant of composite ceramics was decreased and dielectric loss increases. The effect of ZnO addition to 70 wt% BST–30 wt% ZST composition on the microstructure and dielectric properties was investigated. The improvements in dielectric constant, dielectric loss, and microwave dielectric properties of composite ceramics can be achieved by ZnO addition. The sample with 98 wt% (70 wt% BST–30 wt% ZST)–2 wt%ZnO composition exhibits promising dielectric properties, with dielectric constant, loss tangent and tunability at 4 kV/mm, of 125, 0.0016 and 12%, at 10 kHz and room temperature. At ~2 GHz, it possesses a dielectric constant of 101 and a Q factor of 187, which makes it a good candidate for tunable microwave device applications.     

BaFe<Subscript>12</Subscript>O<Subscript>19</Subscript> films produced from BaFe<Subscript>2</Subscript>O<Subscript>4</Subscript>/α-Fe<Subscript>2</Subscript>O<Subscript>3</Subscript> heterostructures

BaFe₁₂O₁₉ hexaferrite films have been produced on thermally oxidized single-crystal silicon (SiO₂/Si) substrates by sequential ion-beam sputtering of BaFe₂O₄ and α-Fe₂O₃ targets in an argon-oxygen atmosphere. Their crystal structure has been studied, and the origin of the impurity phases forming during heat treatment has been identified. The results show that heat treatment may lead to the formation of eutectic melts. As a result, the hexaferrite films may contain spherulites.     

Preparation and luminescence properties of Y<Subscript>3−y</Subscript>Al<Subscript>5−x</Subscript>Ga<Subscript>x</Subscript>O<Subscript>12</Subscript>:Ce<Superscript>3+</Superscript><Subscript>y</Subscript> phosphors

Y_3?yAl_5?xGa_xO₁₂:Ce³⁺_y phosphors were prepared by high temperature solid state reaction method. The crystal structures, the influence of Ga³⁺ concentration on the photoluminescence (PL), cathodoluminescence, thermal stability and morphology of the phosphors were studied in detail. The results indicated that diffraction angle of the samples decreased gradually with the increase of Ga³⁺ ions content in XRD pattern. The emission peak of the spectra show a progressive blue-shift, the intensity increased first and then decreased and the optimal Ga³⁺ concentration in Y_2.94Al_5?xGa_xO₁₂:Ce³⁺_0.06 phosphors is x?=?0.75. The critical concentration of Ce³⁺ in YAGG:Ce³⁺ phosphors is affected with the ratio of Ga³⁺ to Al³⁺ and the Y_2.9Al_4.25Ga_0.75O₁₂:Ce³⁺_0.1 phosphor showed the best performance on PL. However, the optimum concentration of Y_3?yAl_5?xGa_xO₁₂:Ce³⁺_y phosphors is x?=?1.5 and y?=?0.04 when they were excited by cathode ray.     

Investigation of solid solution of ZrP<Subscript>2</Subscript>O<Subscript>7</Subscript>–Sr<Subscript>2</Subscript>P<Subscript>2</Subscript>O<Subscript>7</Subscript>

In this study, ZrP₂O₇ was synthesized by the solid state reaction of ZrO₂ and NH₄H₂PO₄ at 900 °C. Then, in set 1; 10, 5, 1, 0.5, 0.1, 0.05, 0.03% previously prepared Sr₂P₂O₇ were doped into ZrP₂O₇, and Sr₂P₂O₇ slightly affect the unit cell parameter of cubic ZrP₂O₇ (a = 8.248(6)–8.233(8) Å). The reverse of this process was also applied to Sr₂P₂O₇ system (set 2). ZrP₂O₇ changes the unit cell parameters of orthorhombic Sr₂P₂O₇ in between a = 8.909(5)–8.877(5) Å, b = 13.163(3)–13.12(1) Å, and c = 5.403(2)–5.386(4) Å. Analysis of the vibrations of the P₂O ₇ ^4? ion and approximate band assignments for IR and Raman spectra are also reported in this work. Some coincidences in infrared and Raman spectra both sets were found and strong P–O–P bands were observed. Surface morphology, EDX analysis, and thermoluminescence properties of both sets were given the first time in this paper.