Electron beam welding of Ti-15-3 titanium alloy to 304 stainless steel with copper interlayer sheet

Electron beam welding of Ti-15-3 titanium alloy to 304 stainless steel with a copper sheet as interlayer was carried out.Microstructures of the joint were studied by optical microscopy(OM),scanning electron microscopy(SEM) and X-ray diffractometry(XRD).In addition,the mechanical properties of the joint were evaluated by tensile test and the microhardness was measured.These two alloys were successfully welded by adding copper transition layer into the weld.Solid solution with a certain thickness was located at the interfaces between weld and base metal in both sides.Regions inside the weld and near the stainless steel were characterized by solid solution of copper with TiFe2 intermetallics dispersedly distributed in it.While weld near titanium alloy contained Ti-Cu and Ti-Fe-Cu intermetallics layer,in which the hardness of weld came to the highest value.Brittle fracture occurred in the intermetallics layer when the joint was stretched.

Promoting surface reconstruction of NiFe layered double hydroxides via intercalating[Cr(C_(2)O_(4))_(3)]^(3-)for enhanced oxygen evolution

Rationally manipulating surface reconstruction of catalysts for water oxidation,inducing formation and dynamic accumulation of catalytically active centers still face numerous challenges.Herein,the introduction of[Cr(C_(2)O_(4))_(3)]^(3-)into NiFe LDHs by intercalation engineering to promote surface reconstruction achieves an advanced oxygen evolution reaction(OER)activity.In view of the weak electronegativity of Cr^(3+) in[Cr(C_(2)O_(4))_(3)]^(3-),the intercalation of[Cr(C_(2)O_(4))_(3)]^(3-)is expected to result in an electron-rich structure of Fe sites in NiFe LDHs,and higher valence state of Ni can be formed with the charge transfer between Fe and Ni.The optimized electronic structure of NiFe-[Cr(C_(2)O_(4))_(3)]^(3-)-LDHs with more active Ni^(3+) species and the expedited dynamic generation of Ni^(3+) (Fe)OOH phase during the OER process contributed to its excellent catalytic property,revealed by in situ X-ray absorption spectroscopy,Raman spectroscopy,and quasi-in situ X-ray photoelectron spectroscopy.With the modulated electronic structure of metal sites,NiFe-[Cr(C_(2)O_(4))_(3)]^(3-)-LDHs exhibited promoted OER property with a lower overpotential of 236 mV at the current density of 10 mA cm^(-2).This work illustrates the intercalation of conjugated anion to dynamically construct desired Ni^(3+) sites with the optimal electronic environment for improved OER electrocatalysis.

Direct Synthesis of Al_2O_3-modified Li(Ni_(0.5)Co_(0.2)Mn_(0.3))O_2 Cathode Materials for Lithium Ion Batteries

To improve the cyclic stability at high temperature and thermal stability, the spherical Al2O3-modified Li（Ni0.5Co0.2Mn0.3）O2 was synthesized by a modified co-precipitation method, and the physical and electrochemical properties were studied. The TEM images showed that Li（Ni0.5Co0.2Mn0.3）O2 was modified successfully with nano-Al2O3. The discharge capacity retention of Al2O3-modified Li（Ni0.5Co0.2Mn0.3）O2 maintained about 99% after 200 cycles at high temperature（55 ℃）, while that of the bare one was only 86%. Also, unlike bare Li（Ni0.5Co0.2Mn0.3）O2, the Al2O3-modified material cathode exhibited good thermal stability.

Comparison of electrochemical properties of atmospheric pressure plasma coatings for Al_2O_3-3TiO_2 and CoNiCrAlY in sea water

To improve the durability of underwater rotating products,the corrosion characteristics in harsh marine environment were evaluated through various electrochemical experiments on the Al2O3-3TiO2 and CoNiCrAlY coating layers by atmospheric pressure plasma spray coating process.By evaluating the corrosion resistance of these materials,their applicability to environmentally friendly power generation equipment such as blades of tidal current turbines was examined.According to the Tafel analysis for micro-areas including the coating layer,the coating/metal interlayer and the base metal,the Al2O3-3TiO2 coating layer and the CoNiCrAlY coating layer show markedly lower corrosion current density than the base metal.The corrosion current density of the CoNiCrAlY coating layer (9.75316×10-8A/cm2) is about 1.6 times more than that of the Al2O3-3TiO2 coating layer (6.13139×10-8A/cm2).

Nondoped-type White Organic Light-Emitting Diode Using Star-Shaped Hexafluorenylbenzene as an Energy Transfer Layer

White organic light-emitting diodes （WOLEDs） with a structure of indium-tin-oxide （ITO）/N,N＇-bis- （1-naphthyl）-N,N＇-diphenyl- （1, 1＇-biphenyl）-4,4＇-diamine （NPB）/1,2,3,4,5,6-hexakis（9,9-diethyl-9H-fluoren-2- yl）benzene （HKEthFLYPh）/5,6,11,12-tetraphenylnaphtacene （rubrene）/tris（8-hydroxyquinoline） aluminum （Alq3）/Mg：Ag were fabricated by vacuum deposition method, in which a novel star-shaped hexafluorenyl- benzene HKEthFLYPh was used as an energy transfer layer, and an ultrathin layer of rubrene was inserted between HKEthFLYPh and Alq3 layers as a yellow light-emitting layer instead of using a time-consuming doping process. A fairly pure WOLED with Commissions Internationale De L＇Eclairage （CIE） coordinates of （0.32, 0.33） was obtained when the thickness of rubrene was 0.3 nm, and the spectrum was insensitive to the applied voltage. The device yielded a maximum luminance of 4816 cd/m2 at 18 V.

大型预制箱梁节段3层堆存安全性及堆存规则研究

以苏通长江公路大桥引桥75 m跨径预应力混凝土箱梁节段施工为依托,参照JTG/T F50—2011《公路桥涵施工技术规范》建议的预制拼装桥梁节段堆存规则,应用Ansys软件建立大型预制箱梁节段有限元模型,计算并分析预制节段在3层堆存条件下的应力分布和抗裂安全性,提出大型预制箱梁节段3层堆存的合理规则,可供今后类似工程施工参考。

The Effects of Dietary Fatty Acid Pattern on Layer's Performance and Egg Quality

The feeding trial was conducted to determine the effects of flaxseed on layer＇s performance and egg quality, and the effects of the dietary ratio of ω-6 fatty acid to ω-3 fatty acid on fatty acid deposition in yolk using flaxseed as resource of ω-3 fatty acid and sunflower seed as resource of ω-6 fatty acid. 192 20-wk-old Newroman commercial hens were randomly divided into 4 treatment groups with 6 replicates containing 8 birds. The rations corresponding with the four treatments were formulated with 4% flaxseed ＋ 9% sunflower seed, 8% flaxseed ＋ 18% sunflower seed, 15% flaxseed, and soybean meal, respectively. Sunflower seed was unshelled and flaxseed was whole. Ratios of ω-6 fatty acid to ω-3 fatty acid in 4 dietary treatments were 5.67, 5.21, 1.07, and 11.83, respectively. It can be concluded that long-term feeding 15% flaxseed had no significant （P〉 0.05） influence on egg production, egg weight, eggshell quality, yolk weight, and percentage of yolk weight. Dietary ratio of ω-6 fatty acid to ω-3 fatty acid had impact on the 0-3 fatty acid levels in yolk, nevertheless yolk fatty acid profiles were different from those of dietary fatty acid compositions.

Anodic behavior of neodymium in acidic AlCl_3-1-ethyl-3-methyl-imidazolium chloride ionic liquid

The anodic behavior of neodymium in acidic AlCl3-1-ethyl-3-methyl-imidazolium chloride （AIC13-EMIC） ionic liquid was investigated by conducting linear sweep voltammeter and chonopotentiometry. The viscosity of Nd dissolved ionic liquid and the surface morphologies of Nd were characterized using an Ostwald viscometer and a scanning electron microscope, respectively. The chemical composition of Nd surface was indentified by Raman spectra. The results showed that dissolution of Nd under anodic polarization occurred after the breakdown of oxide films. A viscous layer formed at the interface of Nd/ionic liquid during the galvanostatic process of 5 and 20 mA/cm^2. The formation of viscous layer was attributed to the accumulation of Nd dissolved AlCl3-EMIC ionic liquid, which had high viscosity. The oxide films could be removed thoroughly and the surface of Nd was homogeneous without etching pits, when viscous layer formed in the anodic process. Otherwise, the surface showed a pitting morphology.

Layered La-Ba-Cu mixed oxides with perovskite structure as catalyst for NO reduction by CO

The mixed oxides, including LaBa\-2Cu\-3O\-7, LaBaCu\-2O\-5, La\-4BaCu\-5O 12 with perovskite structure, were prepared. The catalysts were characterized by means of chemical analysis, XRD, H\-2_TPR. It was found that their structures were layered ABO\-3 perovskite structure and they were the active catalysts for the NO reduction by CO. The existance of Cu 3+ is an important factor to give the catalysts a high activity for the NO reduction by CO.

Liutex similarity in turbulent boundary layer

Kolmogorov's 1941 theory(K41)of similarity hypotheses and the-5/3 law for energy spectrum are considered as the most important theoretical achievement in turbulence research and the success of the modem turbulence theory.The assumptions of sufficient high Reynolds number and isotropy of turbulence that K41 based upon,however,cannot generally be met in practice,and thus discrepancy is often observed between the f law and direct numerical simulation(DNS)results of boundary layers in wall bounded turbulence,especially for moderate to low Reynolds number flows.Liutex vector is a recently defined new physical quantity which is extracted from turbulent flow to represent the rigid rotation part of fluid motion.Actually,Liutex is free from viscous dissipation and thus independent of Reynolds number,relaxing the very high Reynold number assumption of K41.Liutex similarity has been solidly demonstrated by DNS for a moderate Reynolds number turbulent boundary layer(Reθ≈1000),both the frequency and wavenumber spectrum of Liutex accurately matches the-5/3 law,which is obviously much better than the turbulence energy spectrum,while vorticity and other popular vortex identification methods,Q criterion for example,do not possess such a distinguished feature due to stretching and shearing contamination.

Experimental study on the local similarity scaling of the turbulence spectrum in the turbulent boundary layer

The streamwise fluctuating velocity in the turbulent boundary layer is measured under approximately medium Reynolds Number by hot wire in order to investigate the scaling properties of the overlapped turbulent spectrum among energy-containing area, inertial subrange and dissipation range based on FFT analysis. The experiment indicates that the high Reynolds flow reported before is not indispensable to produce -1 scaling. So far as the measured position is provided with much higher spatial resolution and enough closing to the wall, -1 scaling is determinate to exist when approaching medium Reynolds. The scaling ranges are supposed to begin at inner scale and end in outer scale, which reveals the local similarity of the energy spectrum over the energy-containing eddies near the wall. In the logarithmic area (y+ > 130), -5/3 scaling occurs in the energy spectrum, while moving away from the wall with Reynolds numbers increasing, the inertial subrange extends to the lower wavenumbers. On the condition k1η 0.1, the curves of the turbulence spectrum in the logarithmic layer are superposed, which expresses the similarity of turbulence energy distributed in Komogorov scaling area and exhibits local isotropy characteristics by virtue of the viscous dissipation.