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This work studied cycle stability of dual-phase lithium titanate (LTO)/TiO2 nanowires as a lithium battery anode. Dual-phase LTO/TiO2 nanowires were successfully synthesized by hydrothermal method at various times lithiation of 10, 24, and 48 h at 80 °C. SEM images show that the morphology of dual-phase LTO/TiO2 is nanowires with a size around 100-200 nm in diameter. The XRD analysis result indicates nanowires main components are anatase (TiO2) and spinel Li4Ti5O12. The first discharge specific capacity of LTO/TiO2-10, LTO/TiO2-24, and LTO/TiO2-48 was 181.68, 175.29, and 154.30 mAh/g, respectively. After the rate capacity testing, the LTO/TiO2-10, LTO/TiO2-24, and LTO/TiO2-48 have been maintained at 161.25, 165.25, and 152.53 mAh/g separately. The retentions for each sample were 86.71, 92.86, and 89.79 %. Based on the results of electrochemical performance, increased LTO content helped increase samples cycle stability. However, the prolonged lithiation time also produced impurities, which reduced the cycle stability.

Three sizes of SmMn2O5 nanorods that are labeled with ( ) × axial lengths of 58(17) nm × 25(6) nm, 92(21) nm × 32(8) nm, and 126(25) nm × 52(13) nm were fabricated by the hydrothermal method. All the samples exhibited an antiferroicmagnetic (AFM) peak at approximately 6 K, which was associated with Sm magnetic ordering and no size independence. Another AFM magnetic ordering that belongs to the Mn ion was found with = 58 nm, 92 nm, and 126 nm at 26 K, 28 K, and 30 K, respectively. The spin-orbit interaction increases with size in the magnetic susceptibility experiment. All the samples displayed a hysteresis loop at 2 K. The coercivity decreases as the size increases. The effects of the size on the crystal structure were elucidated from the Raman spectra of the = 92 and 126 nm samples at various temperatures. The 126 nm sample displayed a red-shift for the Ag mode with warming, revealing that the Mn–O bonds are more sensitive to temperature in larger SmMn2O5 nanorods. These results demonstrate that the size effect importantly affects the structure and magnetic properties in SmMn2O5 multiferroic nanorods.

We have successfully synthesized two kinetically stable CuI-MOFs with 2D layered architectures by introduction of β-[Mo8O26]4− clusters, denoted as [CuI2(β-Mo8O26)(bnie)2][Cu2(bnie)2] (NAU-1) and [CuI2(bnie)2]2(β-Mo8O26) (NAU-2) respectively. According to the result of electrochemical analysis, all these framework active materials behave as pseudo-capacitor and exhibit high capacitance and excellent energy delivery efficiency. For instance, the maximum gravimetric capacitance of NAU-1 and NAU-2 electrode is 800 and 828 F g−1 at a current density of 1.0 A g−1 separately. Theory mechanism analyses suggest capacitive (i ∝ v) and diffusion-controlled (i ∝ v1/2) currents contribute equally during redox reaction process. Particularly, after integration of carbon-based conductive matrix with CuI-MOFs, the structural stability and cycling life are both promoted. Whether carbon nanotubes or graphene oxide, they both boost the conductivity of the electrode and the capacitance retentions of these electrodes keep growing trends that all surpass 100% after 5000 continuous cycles. The excellent electrochemical performance may be ascribed to the β-[Mo8O26]4− clusters occupying the void space of 2D layered structures that facilitate electron transport and ions transmission.

A series of MnOx/N-doped carbon/MnO2 composites with high nitrogen amounts, namely MnOx/NC/MnO2, was successfully fabricated. These composites were synthesized by soaking the thermally decomposed products of Mn-MOF precursors in potassium permanganate solutions of different concentrations. The Mn-MOF precursors were constructed from the coordination of N-rich linker, 3-amino-1H-1,2,4-triazole-5-carboxylic acid (HATC) or pyrazine-2,3-dicarboxylic acid (H2PDA) with Mn(II) ions. The as-synthesized composites, particularly the samples with moderate carbon/nitrogen ratios (6.76 and 1.84 for C1- and C2-based composites, respectively,) showed excellent rate capabilities, low series resistances and charge-transfer resistances as well as superior long-term cycling stabilities (more than 88% after 5000 unceasing cycles). This enhancement should be attributed to the inter-effect relationship among carbon, nitrogen and the MnO2 layer, which gives rise to a superior synergistic-effect in minimizing ionic and electronic transmission distances, resulting in better performances.

Two identical layered metal-organic frameworks (MOFs) (CoFRS and NiFRS) are constructed by using flexible 1,10-bis(1,2,4-triazol-1-yl)decane as pillars and 1,4-benzenedicarboxylic acid as rigid linkers. The single-crystal structure analysis indicates that the as-synthesized MOFs possess fluctuant 2D networks with large interlayer lattices. Serving as active electrode elements in supercapacitors, both MOFs deliver excellent rate capabilities, high capacities, and longstanding endurances. Moreover, the new intermediates in two electrodes before and after long-lifespan cycling are also examined, which cannot be identified as metal hydroxides in the peer reports. After assembled into battery-supercapacitor (BatCap) hybrid devices, the NiFRS//activated carbon (AC) device displays better electrochemical results in terms of gravimetric capacitance and cycling performance than CoFRS//AC devices, and a higher energy-density value of 28.7 Wh kg-1 compared to other peer references with MOFs-based electrodes. Furthermore, the possible factors to support the distinct performances are discussed and analyzed.

An oxidation or nitridation treatment was performed on the interfacial layer (IL) with optimal oxidation state in order to form an oxygen diffusion barrier for Ge nMOSFET. Through the analysis of X-ray photoelectron spectroscopy and electrical characterization of Ge nMOSFET, the reaction mechanism and physical model were studied in details. The fewer interface traps and lower subthreshold swing can be achieved by forming oxygen diffusion barrier in an optimal IL with remote NH3 plasma. As compared to devices with oxidation treatments, that improvement can be attributed to the nitrogen passivation and alloy-like interface formation. The proposed oxygen diffusion barrier with remote NH3 plasma treatment on IL is a promising technique to improve the interface properties effectively without influencing equivalent oxide thickness for high performance Ge nMOSFET.

A two-step hydrothermal method was developed to produce CdS nanoparticle–sensitized ZnO nanoneedle heterostructures, which array on copper fiber (CF), and its applications in the field of photocatalysts were also explored. In this novel heterostructure, the CF plays a role in supporting the carriers of CdS nanoparticles–sensitized ZnO nanoneedles. Furthermore, CF is capable of accelerating the exportation of charge carriers. Therefore, CF@ZnO/CdS hierarchical heterostructures present excellent photocatalytic performance under visible light, enabling the decomposition of organic dyes such as RhB within 60 min, with desirable cycling ability. Because of the sustainability and engineering potential of CF in chemistry, it is easy for it to be recycled. This method we developed also conformed to the development of green chemistry without using organic solvents in the entire fabrication process of CF@ZnO/CdS hierarchical heterostructures. This work may pave the way for a useful system to realize efficient charg...

The novel luminescent polymer-rare earth complexes, denoted as (PFSi-IPDI)-Tb(Ⅲ)-Phen, have been successfully synthesized and can be made into flexible films. Amino-modified fluorine silicone oil-isophorone diisocyanate (PFSi-IPDI) was used as the host macromolecular ligand, and 1, 10-Phenanthroline (Phen) as the secondary small-molecular co-ligand. The luminescent lanthanide complexes were characterized by fourier transform infrared (FITR), scanning electron microscope (SEM), thermogravimetric analysis (TGA). The luminescent properties were investigated through photoluminescence excitation (PLE) and emission (PL) spectroscopy. FTIR analysis verifies the successful preparation and integration of PFSi-IPDI to Tb3+. The comparatively uniform morphological structure can be observed in the images of SEM. The polymer-rare earth complexes display the typical luminescence emission peaks under the excitation wavelength of 330 nm. From the decay curve, the short lifetime (about 0.89 ms) is observed for (PFSi-IPDI)-Tb(Ⅲ)-Phen (0.6 mol/L). Moreover, these luminescent polymer-rare earth complexes possess superior thermal stability (T5 > 195 °C). All the interesting results suggest the potential application of the luminescent polymer-rare earth complexes in green-emitting luminescent materials under high temperature.

Two kinds of novel fluorescent films have been successfully synthesized by surface modification on the poly(ethylene- co -acrylic acid) films using the lanthanide (Eu 3+ , Tb 3+ ) complexes. The process consists of three steps: conversion of carboxylic acid groups on the surface of the poly(ethylene- co -acrylic acid) films to acid chloride groups, synthesis of the lanthanide complexes bearing amino groups, and amidation to form the modified films. To characterize the modified films, Fourier transform infrared, thermogravimetric analysis, static water contact angle measurements and photoluminescence tests have been employed. Fourier transform infrared verifies the successful preparation of the lanthanide complexes and the modified poly(ethylene- co -acrylic acid) films. These films can emit strong characteristic red and green light under UV light excitation. In addition, the films both have short lifetime (1.14 ms and 1.21 ms), high thermal stability (T d = 408 °C and 411 °C) and, compared with unmodified ones, increased hydrophilicity. All these results suggest that the modified films have potential application as luminescent materials under high temperature.

Effects of rapid-thermal-annealing (RTA) and microwave annealing (MWA) on Ge pMOSFET with GeOx interfacial layer (IL) and HfO2 gate dielectric were studied in this work. High gate leakage and low hole mobility may be induced by the diffusion of GeOx during RTA thermal process. A high hole mobility of ~510 cm2/V-s, low equivalent oxide thickness (EOT) of ~0.7 nm, and very low gate leakage density of ~10−4 A/cm2 at V = VFB + 1 V in Ge pMOSFET can be simultaneously achieved with the efficient annealing effects of MWA on hydrogen plasma (H*) treated GeOx IL due to the suppression of GeOx out-diffusion. The notable difference between RTA and MWA can be attributed to good annealing effects on gate stack by using a MWA with low effective thermal budget.

Two triarmed organic–inorganic hybrid materials based on carboxylic acid-functionalized polyhedral oligomeric silsesquioxane (APOSS) with/without PS linkers are designed and synthesized (tri-PS-APOSS and tri-APOSS). They can both self-assemble into hollow spherical nanostructures in water/organic mixed solvents, as confirmed by light scattering and TEM techniques, yet they possess completely different mechanisms and driving forces. With the PS linkers, the hybrid forms bilayer vesicles similar to surfactants; while without the PS linkers, the hybrid behaves like hydrophilic macroions and assembles into single-layered, vesicle-like “blackberry”-type structure. Consequently, the trend of the assembly size in response to the change of the solvent polarity is different for the two scenarios. This work shows a simple, universal approach of controlling the mechanism and product of the self-assembly process via minor adjustment of the organic–inorganic hybrid structures.

Well scattered strontium hexaferrites (SrFe12O19) nanoparticles have been successfully synthesized by coprecipitation method using polyvinyl alcohol (PVA) as a surfactant and calcinated at 850 °C. With the aim of exploring the magnetic properties of powders obtained, pH values ranging from 8 to 12. The resulting particles were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, Ultraviolet–Visible spectroscopy, thermogravimetric analysis, scanning electron microscopy, dynamic light scattering and vibrating sample magnetometer. In the pH value range 8–12 inclusively, there is sharp rise in the coercivity but an evident decline in both the saturation and remanence magnetization. Fe2O3, as a secondary phase, was discovered to reduce and even disappeared in higher pH value. Single phase strontium hexaferrite plates roughly 40 nm in size were synthesized at pH = 12, and the resulting powders present a coercivity being as high as 4321 Oe and a weak saturation magnetization. Comparing magnetic property of as-obtained nanoparticles synthesized at low pH values, the material combined with higher pH and PVA is in pure phase, which may pave a way for large-scale application.

This letter analyzes performance and reliability of inverted staggered type amorphous indium–gallium–zinc oxide devices in a moist environment with H2O molecules in the passivation layer. There is a negative threshold voltage shift ( $\vartriangle ~\text{V}_{\mathrm {{th}}}$ ) in the saturation region (VD = 10 V), which increases with decreasing channel length. We propose that this is explained by the drain-induced barrier lowering that is due to the H2O molecules. Moreover, a hydrogen bonding model under bias stress is also proposed, in contrast to the conventional H2O doping model. Recovery behavior after bias stress and ac operation were utilized to distinguish the difference between these models.

Single crystal superalloys have been prepared separately by a grain selector and a seeding technique in a high temperature gradient directional solidification furnace. The orientation characteristics were measured by XRD. Results indicate that for the grain selector method, the crystal solidification begins at the cooling plate with random nucleation, and through mutual competitive growth at the starter block. The grains enter the spiral selector, and finally the single crystal superalloys which are close to direction are obtained. By the seeding technique, by epitaxial growth of partially melted seed crystals, single crystal superalloys which have the same orientation as the seed crystal are obtained.

Permeability barrier imposed by stratum corneum makes an extreme challenge for the topical delivery of plasmid DNA (pDNA), which is widely used in gene therapy. Existing techniques to overcome the skin barrier for bio-macromolecules delivery rely on sophisticated mechanical devices. It is still a big challenge to treat the skin cancer, for example, melanoma, that initiates in the dermal layer by topical gene therapy. To facilitate the skin penetration of pDNA deeply into the melanoma tissues, we here present a cell-penetrating peptide and cationic poly(ethyleneimine) conjugated gold nanoparticle (AuPT) that can compact the pDNAs into cationic nanocomplexes and penetrate through the intact stratum corneum without any additional enhancement used. Moreover, the AuPT is highly efficient in stimulating the intracellular uptake and nuclear targeting of the pDNAs in cells, which guarantees the effective transfection. This study provides evidence that penetrating peptide conjugated cationic gold nanoparticle offers a promising vehicle for both the skin penetration and transfection of pDNAs, possessing great potential in topical gene therapy.

In this work, we report the preparation of lanthanide (Eu3+, Tb3+)-complex-grafted copolymer of methyl methacrylate and maleic anhydride films. The lanthanide complex with three amino groups was used to react with poly(methyl methacrylate-co-maleic anhydride) (P(MMA-MAH)) via the amidation method. Fourier transform infrared (FT-IR), Transmission electron microscope (TEM), Scanning electron microscope (SEM), Thermogravimetric analysis (TGA) were employed to characterize those polymers. Luminescent properties were evaluated through conducting Photoluminescence (PL) excitation spectra, emission spectra and fluorescence decay curves measurements. The infrared analysis reveals the amidation between amino groups and anhydride rings. The comparatively uniform morphology can be observed in the images of TEM and SEM. These polymers can emit intense characteristic lights including red light from Eu3+ ions and green light from Tb3+ ions under 294 nm excitation. The lifetimes of polymers are short (about 1 ms). Meanwhile, these luminescent polymers exhibit high thermal stability (T5 > 200 °C). We also stimulate a lamp to illustrate the possible application. All these approved interesting results suggest that they hold significant promising applications as luminous layers for optoelectronic devices.

Different approaches for the fabrication of CNT-supported Ni-triazole composites, such as room-temperature stirring and hydrothermal treatment for a distinct reaction time has been presented. As a result, various morphologies, MMOF wrapped CNTs, CNTs entangled with an MMOF and CNTs attached on an MMOF, were synthesized and investigated through electrochemical measurements. The as-synthesized CNTs/MMOF-based hybrids, especially for the CNTs/MMOF-8H structure, show a good rate capability after 20 times increase, a superior coulombic efficiency and an excellent long-term cycling stability (more than 98% retained after 2000 cycles). This enhancement can be ascribed to the introduction of the CNT conductive additives, which promote the fast charge-transfer ability of ions and electrons. Even for the other CNTs/MMOF-based composites, the overall electrochemical performances are still superior to those of pristine MMOF electrodes.

In this paper, a helium discharge model under high pressure is established. To qualitatively verify the validity of the model, we compare the results obtained from the previous experiments with those acquired from our model under similar operational conditions. In the simulation model, the electron temperature is obtained according to its relationship with the local electric field. According to the principle of electrical neutrality, the number density of He + and the number density of \begin{document}${\rm{He}}_2^+$\end{document} are also equal to the initial electron density, and we can assume that the He + and the \begin{document}${\rm{He}}_2^+$\end{document} account for 30% and 70%, respectively. For helium and copper electrodes, the secondary electron emission coefficient is 0.19 and the secondary electron average energy is15.3 eV. The Fowler-Nordheim equation is used to calculate the field-emission current density, and the electron flux is calculated according to the “charge conservation condition”. The electron flux is added to COMSOL's corresponding wall boundary, which can play the role of field emission. Finally, the analysis is carried out at a macro level (breakdown voltage) and micro level (spatial electron density). It is found that the field-emission current density is determined by the electric field intensity, the field enhancement factor, and the metal escaping work. The effect of field emission can be ignored when \begin{document}$\beta = 300$\end{document} . However, if \begin{document}$\beta = 400$\end{document} , the influence of field emission on the breakdown is significant when the electric field intensity is above \begin{document}$10\;{\rm{ MV}}/{\rm{m}}$\end{document} . For the breakdown of helium gas with copper serving as a parallel plate electrode, the effect of field emission can be ignored when the electric field intensity is lower than \begin{document}$8\;{\rm{ MV}}/{\rm{m}}$\end{document} . At a micro level, the field emission can provide new "seed electrons" for the discharge space, which can increase the electron density of the whole space and intensify the particle collision reaction, finally leading to the breakdown.

In this paper, the low cycle fatigue crack initiation life was regarded as a process of damage accumulation and a damage accumulation model was established based on the Continuum Damage Mechanics. By the model, we analyzed how the variable amplitude applied at the crack initiation stage influenced the low cycle fatigue life of high temperature materials. With the parameters of GQGH4169 alloy at room temperature, we determined the specific values of damage parameters by finite element method and numerical analysis method. Then, the crack initiation life predictions were carried out. The results show that using this approach can not only predict the crack initiation life of CT specimen accurately, but also reflect a definite influence of variable amplitude on the crack propagation life combining with the Paris Law, and the test costs reduced consequently.

A series of multi-headed giant surfactants based on polystyrene (PS)-polyhedral oligomeric silsesquioxane(s) (POSS) conjugates, with a different number and topology of POSS heads, are found to self-assemble into different supramolecular structures including vesicles, cylindrical and spherical micelles in H2O/DMF mixed solvents. The transitions among different morphologies can be rationally controlled by tuning the number and topology of POSS heads, as well as the macromolecular concentration.

A novel fully capped mesoporous silica (FCMPS) was synthesized by producing a layer of linked polyhedral oligomeric silsesquioxanes (LPOSS) on the surface of a typical mesoporous silica (SBA-15). The structure of FCMPS was characterized using Fourier Transform Infrared (FTIR), Nuclear Magnetic Resonance ( 29 Si NMR), X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), High Resolution Transmission Electron Microscope (HRTEM), Nitrogen adsorption–desorption and thermogravimetric (TG) analyses. Compared with SBA-15, FCMPS has not only high surface area, pore volume and size, but also remarkably improved thermal stability, the initial degradation temperature ( T di ) of FCMPS increases about 194 °C. In addition, FCMPS overcomes the drawback of SBA-15, exhibiting much lower and stable dielectric constant and loss. Based on the synthesis of FCMPS, the FCMPS/bismaleimide resin (BD) hybrids with different contents of FCMPS were prepared, and their dielectric properties were investigated. Results show that FCMPS/BD hybrids have much lower and stable dielectric constant and loss than SBA-15/BD hybrids owing to the special structure of FCMPS. With the addition of 1 wt.% FCMPS into BD resin, the dielectric constant of the resultant hybrid is as low as about 2.50 over the whole frequency from 10 to 10 6 Hz; moreover, the dielectric loss of the hybrid is almost independent on the frequency, and the dielectric loss at higher frequencies (>10 3 Hz) is even lower than that of BD resin. These attractive features make FCMPS have obvious advantage in developing materials with low dielectric constant and loss.

The influence of Re and Ru on segregation and microstructure evolution during heat treatment has been investigated in four Ni-based single-crystal superalloys with varied contents of Re(3%—6%,mass fractions) and Ru(0%and 3%).The additions of Re and Ru lead to the more severe segregation of alloying elements in as-cast structures.However,the effects of Ru on as-cast segregation can be neglected after the stepwise solution heat treatments.The additions of Re and Ru lead to the lowerγ'-coarsening rate,more cuboidalγ'-morphology and reducedγ'-size.Electron microprobe analysis(EPMA) indicates that A1,Ta and Ni partition to theγ'-precipitates,whereas Re and Cr strongly partition to theγ-matrix.In comparison to Re and Cr,Ru and W show the less tendency to partition to theγ-matrix.Additionally,Re increases the supersaturation of Re,Cr, Co and W in theγ-matrix,whereas Ru only slightly suppresses the partition of these TCP-forming elements to theγ-matrix.

The effects of hydrogen-charging on tarnishing film-induced brittle cracking of brass were studied. The tarnishing film was generated on brass samples with various hydrogen concentrations in Mattsson’s solution, then removed from the solution, dried, and subjected to a slow loading rate (loading speed = 0.5 mm/min) in air. The results indicated that hydrogen caused the film-induced brittle cracking to be more difficult to occur and a considerably high concentration of hydrogen could inhibit completely the film-induced brittle cracking. Elastic modulus test results showed that elastic modulus of the brass substrate decreased and elastic modulus of the tarnishing film increased with increasing the hydrogen concentration. Hydrogen inhibiting the film-induced cracking can be ascribed to the fact that hydrogen changed the elastic modulus of substrate and film.

Tarnishing film was developed on the brass surface in Mattsson's solution at room temperature. The filmed brass was removed from the solution, dried, and subjected to a slow strain rate (loading speed = 0.5 mm/min) in air for studying the effect of the film on crack propagation in the brass substrate. It was observed that initial cracks started to emerge in the film and then propagated to the brass matrix in a brittle intergranular manner. However, it changed into a ductile mode after removing the deposited film. The galvanic current between platinum wire and filmed brass sample in Mattson's solution was investigated. The results showed that periodic current fluctuations were observed when the sample was under a constant applied load. These observations showed that the film rupture-formation occurred at cracks under the stress-corrosion cracking condition.

The self-propagating combustion reaction 0.741Mg + 0.247Fe2O3 + 0.188Ni + 0.318Cr → 0.741MgO + Fe0.494Ni0.188Cr0.318 was applied to prepare a nano-MgO reinforced Fe-Cr-Ni composite, by reactive hot pressing (RHP) under a condition of 700°C/30MPa/2h. The densification was enabled by the low temperatures produced by the exothermic reaction. According to TG-DTA and X-ray diffractometry (XRD), the highly-exothermic thermite reaction began at about 600°C and the in-situ formation of composites comprised predominantly of (FCC) Cr0.19Fe0.7Ni0.11, (FCC) Fe-Cr, (BCC) MgO and a small quantity of (BCC) MgFe2O4. The Vickers hardness was 3.67GPa, the three-point bending strength was 112.5±10MPa, and the fracture toughness was 3.28 MPa•m1/2. The microstructure of the composite was observed via scanning electron microscopy. This indicated that the distributions of in-situ-formed (BCC) MgO phases (~800 nanometers) were homogeneous into in a matrix of a fine-grained metallic alloy phases that gather together to form agglomerates in the composite.

A series of N,N‐disubstituted‐4‐[(4‐aminophenyl)diazenyl]benzylidene‐4′‐alkylanilines (azo dyes) were synthesized from the reaction of the corresponding benzaldehyde with alkylanilines. These azo dyes exhibit nematic and SmC phases on heating. Their order parameter, photo‐stability and miscibility were studied by investigation of a representative sample.

A series of new azo dye liquid crystals was prepared by the reaction of the N,N-disubstituted-4-aminophenylazobenzaldehydes with butyl cyanoacetate in the presence of piperidine in refluxing ethanol. The new azo dye liquid crystals possess a SmA phase, and representative samples were found to be reasonably photostable.

Three-dimensions molecular dynamics (MD) method by employing the embedded atom method (EAM) potential is used to simulate the effect of stress corrosion-induced dealloyed layer existed on the surface of a crack of Cu 2 Au alloy on dislocation emission and crack propagation. The simulations show that the existence of a dealloyed layer enhances dislocation emission and crack propagation, i.e., decreases the critical stress intensity for dislocation emission from K Ie =0.62 MPam 1/2 to K Ie *=0.556 MPam 1/2 and that for crack propagating after emitting large amounts of dislocations from K IP =1.14 MPam 1/2 to K IP *=1.06 MPam 1/2 . This indicates that dealloyed layer-induced tensile stress can help the applied stress to enhance dislocation emission and crack extension.

A series of N , N -disubstituted 4-aminophenylazobenzaldehydes (azo dyes) were synthesized by the reaction of phenylpiperazine derivatives with 4-formylbenzenediazonium tetrafluoroborate. The salt was easily prepared by reacting poly(aminobenzaldehyde) with sodium nitrite in the presence of tetrafluoroboric acid. A representative sample was studied by crystallography, and the charge distribution of the molecule was calculated with the aim of understanding the form of molecular stacking on the basis of crystal data. The mesogenic behaviour of the azo dyes was also studied.

The synthesis, characterization, and mesomorphic properties of a new type of heteronuclear compounds derived from pyrimidine as core group are reported. These compounds were prepared by condensation reactions of appropriate acetophenones and benzonitriles in the presence of trifluoromethanesulphonic anhydride. They were characterized by 1H and 13C NMR spectroscopy and elemental analysis, and their phase transitions characterized and studied by thermal analysis and polarizating microscopy. These compounds exhibit hexagonal columnar (Colh) phases, as expected for disk-like molecules; the formation of columnar phases was found to be dependent on the numbers of alkoxy side chains attached. For those compounds having the same numbers of flexible side chains attached, the one with a preferred unsymmetric structure exhibited better mesomorphic properties. The observed improved mesomorphic behaviour of these compounds over other similar all-carbon heterocyclic compounds is attributed to the greater polarization o...

High quality and uniform ZnO:Mn ((ZnMn)O) nanoparticles were successfully synthesized using chemical method without using any organic solvents in the fabrication processes, which is combined with the development of green chemistry. The obtained nanoparticles were characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), x-ray photoelectron spectra (XPS), UV–visible absorption (UV–vis), photoluminescence (PL), fourier transform infrared spectroscopy (FT–IR), thermogravimetry (TG) and vibrating sample magnetometer (VSM), which is central to know fully about crystal quality, the structure, surface composition, optical and magnetic property of (ZnMn)O nanoparticles. We not only provided a new kind of morphology of ZnO but also explored a facile synthesis and enviromentally friendly method, which is easy to control and industrialize. The photocatalytic property was tested by degradation of methylene blue (MB) solution. The result not only exhibited good visible light-driven photocatalytic property owing to the wide band gap of (ZnMn)O in aqueous solution, but also showed high photocatalytic stability and outstanding cycling stability. (ZnMn)O products exhibit a high rate degradation of 5 mg l−1 MB aqueous solution and achieve almost complete degradation of MB aqueous solution under light resource within 70 min.

The threshold stress intensity of stress corrosion cracking (SCC) in the NaCI solution, K ISCC , has been measured for five low alloy steels. The effects of yield strength, alloy elements, microstructure and grain size on K ISCC were studied. The results showed that K ISCC decreased exponentially with increasing yield strength, σ ys , i.e., K ISCC = 1.38 10 6 exp(-8.26 10 -3 σ ys ) for 40CrMoV steel and K ISCC = 1.42. 10 6 exp(-4.66. 10 -3 σ ys ) for 30CrMnSiNi steel. For low-alloy high-strength steels with σ ys = 1400 MPa, the effect of alloy elements, microstructure and grain diameter larger than 7 μm on K ISCC was little. The threshold stress intensity of hydrogen-induced cracking during dynamical charging for 40CrMoTi steel decreased linearly with the logarithm of the concentration of diffusible hydrogen, C 0 , i.e., K IH = 31.3-9.1InC 0 . This equation was also applicable to SCC of a high-strength steel in aqueous solution, and in this case, C 0 is constant. The critical hydrogen enrichment concentration, C th , necessary for SCC of high-strength steel in water decreased exponentially with the increase in yield strength. It was possible to deduce the relationship between K ISCC and σ ys , i.e., K ISCC = Ak 1 exp(-k 2 σ ys ), where A = 3RT √πρ /2(1 + v) V H , k 1 and k 2 are constants, which depend upon the compositions and microstructure of the steel as well as the test conditions.

In this paper, a type of typical PD source, micro-void discharge, is designed and fabricated to imitate the defects in GIS online. The void in solid insulation is carved by the laser inside-carving machine and the machining operation, respectively. Comparing these two kinds of void discharge, a single void discharge form can be obtained using the void carved by the laser inside-carving machine. The void discharge characteristics in power frequency and high frequency are also compared and analyzed. The singleness of discharge forms in high frequency is better. The experimental results will be applied in PD monitoring and materials testing.

Three errors or discrepancies in a previous paper [1]are discussed and corrected, and additional data on solubility of hydrogen in alpha-2 titanium aluminide alloys are presented. An equation suitable for low-temperature hydrogen solubility is proposed, agreeing well with numerous published and unpublished data. An erroneous phase identification is corrected, from the former claim of FCC hydride, to the orthorhombic or O phase.

Hydrogen induced void nucleation of 310 stainless steel was investigated. Experimental results indicated that hydrogen promoted void nucleation. A new model of hydrogen induced void nucleation was proposed. The basic idea of this model is that hydrogen induces void nucleation not only by promoting microcrack nucleation but also by promoting the transition of microcrack to microvoid; hydrogen also increases the stability of a microvoid by forming hydrogen pressure in the microvoid and by decreasing the void surface energy.

The anisotropic behavior of fracture toughness and stress corrosion cracking of materials was analysed by fractal geometry in this paper. The results indicate that the K1c and K1scc in the S-L, L-T and L-S orientations are different and obey K S−L 1c L−T 1c L−S 1c K S−L 1scc L−T 1scc L−S 1scc .

The corrosion for brass in the water at room temperature can facilitate dislocation emission, multiplication and motion.

When the fracture appearance of materials can be considered as approximately fractal, a relationship between j{sub 1c} and fractal value of the fracture surface for ductile materials can be established. The new theoretical formula is J{sub 1c} = ({sigma}{sub 0}/3)ln((4{sup (1{minus}D{sub F}{sup {minus}1})}{minus} 1)/12f{sub p})l{sub 0} where {sigma}{sub 0} is the tensile strength of the material, D{sub F} is the fractal value of the fracture surface, f{sub p} is the volume fraction of void initiating particles, l{sub 0} is the characteristic distance. The formula shows that the higher the fractal value of the fracture surface, the larger the J{sub 1c} value. There is a correlation between hydrogen-induced J{sub 1c} decrease and hydrogen decreases in the fractal value of the fracture surface, which is consistent with experimental observations.

Varying amounts of hydrogen were dissolved in the titanium aluminide alloy Ti-24Al-llNb (atomic percent). Virtually all of this hydrogen probably precipitated as hydride on cooling because the terminal solubility in the dominant Ti3Al phase is very low at room temperature. Although the yield strength (YS) increased, the ultimate tensile strength (UTS), ductility, fracture stress in notched bend bars, and fracture toughness decreased with increasing amounts of hydride. The strength and fracture properties, for all hydride contents, did not change with testing speed below about 5 to 50 mm/min but decreased steeply for speeds greater than that. The presence of hydride decreased the critical value of testing speed by about an order of magnitude. Brittle cracks in bluntly notched bend bars, with or without hydride, nucleated at the notch root or at a distance below the root which was less than one fifth of the distance to the peak stress location. This result suggests that the cleavagelike cracking in this material is not controlled by normal stress alone but has some dependence on the applied strain. The fracture surfaces of notched or precracked specimens, with or without hydride, consisted entirely of cleavagelike fracture, but these cracks exhibited stable crack propagation. This permitted both the measurement of crack resistance or R curves and also observation of the initiation and propagation of the crack with increasing KI. The results showed that cracks initiated discontinuously at characteristic sites within the plastic zone and along the slip bands when the plastic deformation ahead of the precrack developed to a particular and reproducible extent. Literature cleavage models were compared to results for the present tests.

The dissolution of hydrogen in a titanum aluminide alloy based on Ti3Al, Ti-24 Al-11 Nb, has been measured as a function of temperature and hydrogen pressure. Both the terminal solubility and the overall solubility, or total uptake of hydrogen, were determined. The terminal solubility of hydrogen in the α2 matric phase increases with temperature, while the overall solubility decreases with increasing temperature in the high-temperature region. The partial molar heat of solution in the α2 phase was determined to be−(21.97 ± 1.46) kJ/mol [H], while the partial molar heat of formation of the hydride phase was −(70.29 ± 2.34) kJ/mol [H]. The standard partial molar free energy of hydrogen in the α2 phase in equilibrium with the hydride was −(74,060 ± 2000) + (87.8 ± 2.1) T J/mol [H].

Fracture mechanisms in fully lamellar γ-TiAl alloys were studied by investigating interactions between cracks and lamellae within grain or grain boundaries using in situ SEM technique. The results showed that the fracture mechanisms depended on not only lamellar orientation to loading axis but also the type of grain boundary encountered.

As physical model used to interpret the fluid behavior when it passes through a semi-permeable membrane, Kedem-Ketchalsky’s (K-K) equations [1, 2] were successfully used in a bunch of filtration processes. However, because they were developed and dedicated to normal ultra- and micro-filtration systems, their limitations were obviously observed in some sort of nano-filtration processes that the pore size of the filtration membrane is only several nanometers. This paper analyzed the feasible utilization scopes of K-K equations. And two methods, Molecular Dynamics (MD) method and Computational Fluid Dynamics (CFD) method, used respectively to analyze nano- and ultra-filtration processes are introduced in this paper.Copyright © 2009 by ASME