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Based on the online monitoring data of VOCs, O

Isothermal compression experiments of vapor-grown carbon nanofiber (VGCNF)-reinforced aluminum matrix (VGCNF/Al) composites and pure aluminum (Al) were conducted at deformation temperatures from 573 K to 723 K and strain rates from 0.01 to 1 s−1. It was found that the VGCNF/Al composites and pure Al had depressed dynamic recrystallization percent in the high-power dissipation efficiency regions. Upon comparing the processing maps for different strains, it was found that the high-power dissipation efficiency regions of the VGCNF/Al composites and pure Al moved from the low strain rate region to the high strain rate region. The kernel average misorientation images showed that there were lots of low-angle grain boundaries in the high strain rate region. The low-angle grain boundaries did not have enough time to transform into high-angle grain boundaries, resulting in a depressed percentage of dynamic recrystallization. The addition of VGCNFs led to an increased low-angle grain boundary density. As a result, the phenomenon of high-power dissipation regions in the high strain rate regions correspond to the low percentage of dynamic recrystallization was more obvious.

The precipitation behavior of α phase in a β-quenched Ti-55511 alloy during high-temperature compression is investigated. The influences of deformation parameters on the flow characteristics, microstructural evolution, as well as the precipitation behavior of α phase, are discussed. Results show that the flow stress features and the dominant softening mechanism are sensitive to the deformation parameters. At low strain rates or high deformation temperatures, the main softening mechanism is dynamic recovery. But, the dynamic recrystallization becomes the dominant softening mechanism at high strain rates or low temperatures. At low strain rates, the continuous strengthening, induced by the pinning effect of α precipitates, happens at the late period of deformation. Distribution of α precipitates is not greatly affected by deformation parameters. In the region near β grain boundary, α precipitates are densely distributed with few orientations. While in the central region of β grain, the α precipitates are distributed a bit more sparsely with several scattering orientations. In addition, with increasing deformation temperature, the content, aspect ratio and size of α phases decrease. However, with increasing strain rate, the content, aspect ratio and size first increase and then decrease. Furthermore, the peak value of aspect ratio appears at 0.01 s−1.

In this study, a heat source model designed explicitly for rectangular laser heat sources was developed to simulate the temperature field during the laser hot wire cladding process. The influence of the temperature field on the solidified microstructure was investigated. The difference in morphology and size of solidified microstructure was mainly caused by temperature gradient and cooling rate. The grain morphology in the edge region was mainly columnar crystal with small size. The grain morphology in the central area was mainly equiaxed crystals with the larger size. This study provided a reference for understanding the characteristics of the solidification microstructure and its formation during laser hot wire cladding process.

Laser hot wire cladding is an efficient and energy-saving additive manufacturing process, which is used in coating, repair, and 3D printing. In this study, 308L stainless steel wire was deposited on the low carbon steel substrate using Laser hot wire cladding technology. The microstructure evolution and microhardness changes in the heat-affected zone of the substrate and the cladding layer near the laser cladding interface were studied in detail by using optical microscopy, electron backscatter diffraction and microhardness tests. The phase transformations and the relationship between microstructure and mechanical properties of the cladding layer were discussed. Owing to the dual effect of temperature gradient and cooling rate, the grain morphology in the central region of the cladding layer is equiaxed, while the edge region is mostly columnar dendritic morphology along the structural direction. There is a dilution zone composed of single austenite near the interface of the cladding layer. In the cladding layer, the ferrite-austenite solidification mode is dominant, and the austenite-ferrite solidification mode is also found in local areas. The carbon migration process from the substrate to the cladding layer promotes the austenite-ferrite mode. The heat-affected zone microstructure consists mainly of ferrite and tempered bainite, and slatted martensite can be observed near the interface. The electron backscatter diffraction results demonstrate the existence of martensite in the heat-affected zone. The texture is more apparent in the cladding layer, while the heat-affected zone contains more residual strain and higher dislocation density. The average grain size in the heat-affected zone region is about 4 μm, while the average grain size in the cladding layer is above 14 μm. The hardness of the heat-affected zone near the interface is the highest due to numerous factors, such as grain size, microstructure transformation and dislocation density. The yield strength increases with the decrease of grain size and texture strength, demonstrating the correlation between microstructure and mechanical properties.

Laser hot wire cladding (LHWC) technology has been proved to be a very efficient laser cladding manufacturing process due to its advantages of fast deposition rate, high material utilization rate, and less environmental pollution. In this study, LHWC technology was used to prepare multiple layers of 308L stainless steel coatings on ordinary mild carbon steel substrates. The microstructure of the weldment section was evaluated by optical microscopy (OM). The results showed that the heat-affected zone (HAZ) of the sample was small, with a height of 1.58 mm and an area of 14.28 mm2. The metallurgical bonding between the substrate and coating was good. Because of the temperature gradient and grain growth rate, the grain morphologies in the different coating regions were different. From the bottom to the top, the grain morphologies were planar crystals, columnar dendrites, and equiaxed grains. Electron backscatter diffraction (EBSD) was used to obtain crystallographic information on the entire section of the sample. The interior of the cladding layer was mainly composed of columnar grains growing along the structural direction, most of which were coarse grains. The matrix and the HAZ consisted of fine equiaxed grains, and the crystal orientations were randomly distributed without obviously preferred orientations. Hardness analysis performed that the hardness of the HAZ was the highest, and the matrix had the lowest hardness. The hardness was higher in the layer-to-layer fusion zone and then gradually decreased with an increase in the cladding height inside each layer. The tensile test results illustrated that the elongation of the cladding layer (44.8 %) was higher than that of the HAZ (32.1 %) and the matrix (20.4 %) because the tensile direction of the tensile sample in the cladding layer was parallel to the laser scanning direction, which improved the tensile performance. The average grain size of the HAZ was the smallest, owing to the effect of fine grain strengthening, and the tensile strength was the highest(585 MPa). According to the tensile fracture profile, the sample matrix, HAZ, and the cladding layer exhibited ductile fractures.

The precipitation orientation of α phases in a Ti-55511 alloy during the heat treatment and the subsequent hot deformation is investigated. It is observed that the β grains prominently influence the precipitation process of α phases, i.e., for the neighbouring β grains without similar {110} pole, the precipitation orientation of grain boundary (GB) α phases (αGB) keep {0001}//{110}β1 or {0001}//{110}β2 to maintain the burgers orientation relationship (BOR) with the neighbouring β grains. For the neighbouring β grains with similar {110} pole, the {0001} poles of αGB phases precipitate parallel to this similar {110} pole and maintain BOR with the neighbouring β grains. For the neighbouring β grains with multiple similar {110} poles, the {0001} poles of αGB phases precipitate along these similar poles and maintain BOR with the neighbouring β grains. Besides, the interface instability nucleation and sympathetic nucleation are the main nucleation modes of the GB widmanstatten α phase (αWGB), which primarily precipitate within β grains with the similar orientation of αGB phases. The intracrystalline widmanstatten phase (αWI) precipitate in a single β grain with 12 precipitation orientations. The BOR between αWI phases and β grains is destroyed during the subsequent hot compressive deformation.

The effect of MnS inclusions on the plastic deformation and fracture behavior of a steel matrix at high temperature was studied. The macroscopic mechanical properties of the material were analyzed using high-temperature uniaxial tensile testing. Numerical simulations were performed by combining the response surface method and finite element simulations. The Gurson–Tvergaard–Needleman damage parameters and the void growth accelerating factor (k) were obtained at different temperatures. Through the fracture analysis and microstructure analysis of the samples at different temperatures, the reasons that affect the macro mechanical properties of the materials are obtained. At 900 °C–1200 °C, there was a large difference in strength and toughness between steels with and without MnS inclusions. The strength of the materials was determined by both the stress intensification caused by the MnS inclusions and stress softening due to dynamic recrystallization (DRX). The plasticity of the materials was jointly determined by the MnS inclusions promoting void initiation and growth, and the DRX inhibiting void growth and coalescence. Moreover, the accelerating factor of void growth (k) reflected the comprehensive effect of MnS and temperature on the evolution of voids in the matrix.

Vapor-grown carbon nanofiber (VGCNF) reinforced aluminum (Al) matrix composites were prepared by spark plasma sintering. Isothermal compression experiments were conducted over a temperature range of 573 K–723 K at strain rates from 0.01 s−1 to 1 s−1. The effect of the addition of VGCNF on the thermal deformation properties of Al matrix was investigated by comparison with pure Al. The results indicate that the composite material has greater high-temperature strength than pure Al. VGCNF withstands stress through the load transfer mechanism in the Al matrix, however, it causes a significant change in the microstructure of the Al matrix. Lattice distortion of the base metal and grain refinement improve the strength of the material. During the thermal deformation process, the VGCNF/Al composite clearly exhibited softening. The difference in the morphology of the reinforced mass before and after the thermal deformation indicated that the sliding of tubular VGCNF was one of the factors leading to the softening. The microstructure after thermal deformation was analyzed by electron backscatter diffraction. It was found that VGCNF promoted the continuous dynamic recrystallization of the Al matrix, which led to softening of the material.

Abnormal cholesterol metabolism is an established feature of Alzheimer’s disease (AD). Cerebrospinal fluid (CSF) is the fluid surrounding the central nervous system, and the protein and lipid content alterations in the CSF could be biomarkers for degenerative changes in the brain. The laboratory diagnosis of AD is limited to the analysis of three biomarkers in CSF: Aβ42, total tau, and phospho-tau. The purpose of this analysis is to systematically analyze the available data describing the biomarkers of cholesterol and its metabolites in the CSF of subjects with AD. MEDLINE, EMBASE, and the Cochrane Central database were systematically queried to collect studies that have evaluated the markers of cholesterol and its metabolites in the CSF of subjects with mild cognitive impairment (MCI) or AD and age-matched controls. Analysis of the published data shows that the levels of cholesterol are increased in MCI subjects; 24-hydroxycholesterol and 27-hydroxycholesterol are elevated in AD and MCI subjects compared to controls. There is a significant dysfunction of cholesterol metabolism in the CSF of AD subjects. This analysis indicates that in addition to the available biomarkers in the CSF, such as Aβ42, total tau, and phospho-tau, 24-hydroxycholesterol, 27-hydroxycholesterol, and cholesterol appear to be sensitive biomarkers for the evaluation of MCI and AD.

Nasopharyngeal carcinoma (NPC) is a malignancy with a high metastatic ability. Recent studies have implicated the role of chromodomain helicase/ATPase DNA binding protein 1-like (CHD1L) gene as a novel oncogene; however, the functional role of CHD1L in NPC remains unknown. The aim of this study was to evaluate the clinical significance of CHD1L positivity in NPC. CHD1L protein expression was examined by performing western blot analysis of 30 fresh NPC tissues and conducting immunohistochemistry tests of 133 NPC samples between December 1, 2005 and December 1, 2009. The correlations of CHD1L expression status with clinicopathological features and prognosis were investigated. Immunohistochemical analysis showed that 88 of 133 (66.2%) paraffin-embedded NPC biopsies exhibited positive expression of CHD1L, but all non-cancerous nasopharyngeal specimens were negative for CHD1L expression. In addition, positive CHD1L expression was strongly associated with an advanced clinical stage (P=0.016), recurrence (P=0.002) and the metastasis status (P=0.031) of NPC. Kaplan-Meier survival analysis demonstrated that patients with CHD1L-positive NPC had significantly shorter overall survival (P

The hot deformation behavior and microstructural evolution of a Ti-55511 alloy in α+β region are investigated by uniaxial compressive tests at elevated temperatures. Transmission Electron Microscope (TEM) and Electron Backscattered Diffraction (EBSD) are employed to observe the microstructures. The spheroidization of lamellate α phases and the dynamic recrystallization (DRX) of β grains are analyzed. It is observed that the flow characteristics are prominently affected by deformation parameters, i.e., the flow stress, peak stress and flow softening stress decrease with the reduced strain rate or the increased deformation temperature. When the deformation temperature is slightly raised or the strain rate is properly reduced, the fraction of spheroidized α phase greatly increases. The substructures are formed in the lamellate α phase, and the β phase wedges into the lamellate α phase. Then, the lamellate α phase is fragmentized and spheroidized. The DRX of β grains is promoted with the raised strain rate or the reduced deformation temperature. Additionally, the higher dislocation density and obvious dislocation pile-ups can be noticed at the α/β interface, which induces the DRX nucleation of β grains at the α/β interface.

Seismic damage was the key reason which resulted in the serviceability degradation or collapse of the bridge. How to quantify the seismic damage and evaluate the seismic performance of the bridge under earthquakes through the damage analysis was the significant research direction in the performance based seismic design. In this paper the Park-Ang model (a well-known dual parameters model) and its modification version used for the damage evaluation of the concrete structure were compared. Furthermore, through the definition of the damage indices of the models based on the modified Park-Ang model and the descending slope of the IDA(incremental dynamic analysis) curve, the seismic damage levels of the typical bridge in the urban rail transit line under the designated earthquakes were analyzed, respectively. It was shown from the results that the calculated results from the two model was essentially consistent. The damage analysis based evaluation method was feasibly used for the seismic performance evaluation of the bridge.

The integral top cover for nuclear reactor pressure vessel is an important force component in the pressure vessel. It works under the HPHT and radiation long time, which increases forging difficultly and needs extremely high quality. Due to the effect of bi-directional tensile stress in spherical part during the shape forming stage of the integral top cover, it is easy to make holes and other defects of the blank extend. Then, it is necessary to study the behavior of the inner hole defect of integral top cover. This paper, by numerical simulation technology, concrete analyses the volume of the hole defect, the size of the hole defect and variation of the hole edges in the stress-strain fields during the shape forming stage of the integral top cover. It researches the control scope of the original size of blank holes when the integral top cover forging meet the requirements of the flaw detection. Research results show that, according to the requirements of volume and maximum size permissible value, the diameter of holes in the integral top cover blank should be respectively less than 1.8 mm, 1.5 mm.

AP1000 steam generator of nuclear power is an important equipment in the PWR nuclear power plant and the structure of its bi-straight tapered cylinder forging is complex, which increases forming difficultly. In this paper, forming process of bi-straight tapered cylinder forging is determinated by numerical simulation and physical experiment. Influence law of dimension parameters of blank and auxiliary of forging forming quality is studied by numerical simulation. The lead specimen forming physical experiment of ratio of 1:15 validates the feasibility of bi-straight tapered cylinder forging forming process and finds that the results of numerical simulation are agreed well with the physical experiment.

316LN is a type of austenitic stainless steel whose grain refinement only depends on hot deformation. The true stress–strain curves of 316LN were obtained by means of hot compression experiments conducted at a temperature range of 900–1200°C and at a strain rate range of 0·001–10 s−1. The influence of deformation parameters on the microstructure of 316LN was analysed. Both the constitutive equation for 316LN and the model of grain size after dynamic recrystallisation were established, and the effect of different deformation conditions on the microstructure was analysed. The results show that the suitable working region is the one with a relatively higher deformation temperature and a lower strain rate, in which the dynamic recrystallisation is finely conducted. Moreover, the working region that should be avoided during hot deformation was indicated.

The cosine solution of the Fick-2 Law, which was considered as the mathematical model of homogenization of dendritic segregation, has always been used to analyze high temperature diffusion. Cosine solution can not exactly describe the actual distribution of alloying elements in dendrite, as the slope of cosine curve is quite gentle. Based on segregation ratio SR, a new mathematical model was established by using Gauss solution of the Fick-2 Law. The new model could describe the evolution of homogenization of alloying elements during the process of high temperature, which was proved by some specific examples.

A series of novel covalently connected azonaphthalene porphyrin derivatives were prepared by linking azonaphthalene groups through a diazo-coupling reaction. They were characterized by UV–vis, IR, 1 H NMR and ESI-MS spectroscopic techniques. Azo–hydrazone tautomerism was studied using 1 H NMR and UV–vis techniques. The two chromophores of these derivatives exhibited their absorption spectroscopic properties and the effect of solvent upon the absorption ability was examined. In the fluorescence emission spectra, intermolecular fluorescence quenching was detected.

Isatin undergoes regioselective 1,3‐dipolar cycloaddition reactions with porphyrin azomethine ylides derived from Ni(II) β‐formyl‐meso‐tetraphenylporphyrins in the presence of N‐methylglycine to afford novel spiro porphyrin derivatives.

Isothermal vapor–liquid equilibrium data are measured for the ternary system methanol + dimethyl carbonate (DMC) + dimethyl oxalate (DMO) and constituent binary systems at different temperatures. The activity coefficients were found to be thermodynamically consistent and were correlated by the Wilson, NRTL and UNIQUAC equations. The correlated parameters of the constituent binary systems were used to calculate the phase behavior of the ternary mixture, which showed satisfactory agreement with the experiments.

The title compound, C44H42N4O5S, was synthesized by the inter­molecular [3+2] cyclo­addition of an azomethine ylide, derived from isatin and sarcosine by a deca­rboxylative route, and 5-(4-methoxyphen­yl-10-(4-methoxy)benzyl­idene-2-(4-methoxy)benzyl­idene-2,3,6,7,8,9-hexa­hydro-5H,10H-cyclohepta­[1,2-d]thia­zolo[3,2-a]pyrimidin-3-one. In the mol­ecule, the two spiro junctions link a planar 2-oxindole ring, a pyrrolidine ring in an envelope conformation and a 10-(aryl­methyl­ene)hexa­hydro­cyclo­hepta­[1,2-d]thia­zolo[3,2-a]pyrimidin-3-one ring. The packing of the mol­ecules in the crystal structure is mainly governed by N—H⋯N hydrogen bonds.

The structure of the centrosymmetric title compound, C8H6Cl2N2O2·2C3H7NO, shows that the hydro­ximo­yl chloride substituent has an essentially planar arrangement and the dihedral angle between this plane and the benzene plane is 18.3 (4)°. The hydro­ximo­yl chloride group has a cis configuration. The packing can be described as a polymeric arrangement of mol­ecules linked through O—H⋯O hydrogen bonds.

The title compound, C13H10N2O2, is approximately planar in the solid state and displays a trans configuration with respect to the azo double bond. Molecules form infinite chains linked by O—H⋯O hydrogen bonds along the a axis.

The title compound, C41H32Cl4N4O2S, was synthesized by the inter­molecular [3 + 2] cyclo­addition of azomethine ylide, derived from isatin and sarcosine by a deca­rboxylative route, and 5-(4-chloro)phen­yl-10-(4-chloro)benzyl­idene-2-(2,4-dichloro)­benzyl­idene-2,3,6,7,8,9-hexa­hydro-5H,10H-cyclohepteno[1,2-d]thia­zolo[3,2-a]pyrimidin-3-one. In the mol­ecule, the two spiro junctions link a planar 2-oxindole ring, a pyrrolidine ring in an envelope conformation and a 10-(aryl­methyl­ene)hexa­hydro­cyclo­hepteno[1,2-d]thia­zolo­[3,2-a]­pyrimidin-3-one ring. The packing of the mol­ecules in the crystal structure is mainly due to N—H⋯O hydrogen bonds.

Novel isoxazole-fused chlorins and isobacteriochlorins were synthesized by the 1,3-dipolar cycloaddition reactions of meso-tetraphenylporphyrins with nitrile oxide.

By using phospholipid fatty acids (PLFA) method, this paper studied the soil microbial community structure in the soybean fields with different chlorimuron-ethyl application history in Weihe district of Heilongjiang Province. In the meantime, the residual amount of chlorimuron-ethyl in soil was determined. There was a very low residual of chlorimuron-ethyl in soil under the conditions of different chlorimuron-ethyl application history. With the increasing year of chlorimuron-ethyl application, the total concentration of soil microbial PLFA and the ratios of fungi/bacteria and Gram negative/Gram positive bacteria decreased, and the microbial stress level increased. Principal component analysis (PCA) showed that long-term application of chlorimuron-ethyl into soybean field changed the soil microbial community structure significantly.

In this paper, a simple, and rapid analysis of bromoxynil octanoate is reported for soil, corn leaves, and corn seeds by utilizing one-step liquid-liquid extraction and partitioning, followed by GC with electron capture (ECD) and mass spectrometry (MS) detection. The method was validated by recovery experiments and assessment of matrix effects. Recoveries for GC-ECD and GC/MS were 82.3-110.7% with a relative standard deviation of14% using matrix-matched calibration solutions for quantification. The limit of quantitation (LOQ) values were 0.005 and 0.2 mg/kg for the ECD and MS detector, respectively, depending on the sensitivity of the target compound. The concentration levels for bromoxynil octanoate residue found in soil, corn leaves, and corn seeds from field experiments were clearly below the LOQ of the ECD detector. The half-life times of bromoxynil octanoate were 2.2-4.2 days in soil and corn leaves. These results indicated that the developed method was appropriate for analysis of bromoxynil octanoate in soil and corn samples.

The inorganic particles hybrid polyimide films are newly emerging advanced materials with excellent corona-resistant and have been widely used in frequency control motor. The Al2O3/PI hybrid films with different Al2O3 contents were prepared by superfine aluminum power treated by coupling agent and polyamide acid (PAA). Qualitative analysis and quantitative analysis on the inorganic content to it were conducted using Fourier Transform Infrared Spectroscope (FTIR), X-ray photoelectron spectroscopy (XPS), Inductively coupled plasma spectrometry (ICP), Gravimetric method, Thermogravimetric Analysis (TG/air atmosphere). It was found that FTIR and XPS are good qualitative analysis methods. FTIR is used to inference possible components by analyzing the structure of material. The method has a lot of advantages such as easily operational, good repeatability, high accuracy and so on. XPS is mainly used to get information of elements contained in the material, it provides information about the core level binding energies and oxidation states of complexes. It can be used to identify the species and valence states of elements, measure the relative content of elements. The relative standard deviations (RSDs) of XPS and TG are too great to perform quantitative analysis, the RSDs of XPS are all above 5.0%, and TG's RSDs are also above 2.0%. So they can be only used as semiquantitative analysis methods. On the contrary, ICP and Gravimetric method are two excellent quantitative analysis methods, their RSDs are all below 1.0%. Moreover Gravimetric method only can be used to analyze single inorganic constituent complex material, although its measured value is closest approach to theoretical value. ICP is the most accurate method and it can be used to analyze multi inorganic components in complex material, this method proved to be easily operational, rapid, highly sensitive, and accurate, and can be adopted as the method of determining many elements simultaneously. So a method was got to analysis of inorganic constituent in complex material from the conclusion upward. Firstly, components in complex material are defined by using FTIR and XPS as qualitative analysis methods and then using the result of XPS as a reference, exactly quantitative analysis of inorganic constituent in complex material was performed by using Gravimetric method and ICP.