A functionalized activated carbon adsorbent prepared from waste amidoxime resin by modifying with H3PO4 and ZnCl2 and its excellent Cr(Ⅵ) adsorption

With the application of resins in various fields, numerous waste resins that are difficult to treat have been produced. The industrial wastewater containing Cr(Ⅵ) has severely polluted soil and groundwater environments, thereby endangering human health. Therefore, in this paper, a novel functionalized mesoporous adsorbent PPR-Z was synthesized from waste amidoxime resin for adsorbing Cr(Ⅵ). The waste amidoxime resin was first modified with H3PO4 and ZnCl2, and subsequently, it was carbonized thr...     

Reduction and melting behavior of carbon composite lateritic bauxite pellets

Direct reduction of low-grade lateritic bauxite was studied at high temperature to recover Fe and beneficiate Al₂O₃ slag. The results show that a metallization rate of 97.9% and a nugget recovery rate of 85.1% can be achieved when the reducing and melting temperatures are 1350 and 1480℃, respectively. Moreover, a higher-grade calcium aluminate slag (Al₂O₃=50.52wt%) can also be obtained, which is mainly composed of α-Al₂O₃, hercynite (FeAl₂O₄), and gehlenite (Ca₂Al₂SiO₇). In addition, high-quality iron nuggets have been produced from low-grade lateritic bauxite. The nugget is mainly composed of iron (93.82wt%) and carbon (3.86wt%), with almost no gangue (slag).     

Hot deformation mechanism and microstructure evolution of an ultra-high nitrogen austenitic steel containing Nb and V

The flow curves of an ultra-high nitrogen austenitic steel containing niobium (Nb) and vanadium (V) were obtained by hot compression deformation at temperatures ranging from 1000℃ to 1200℃ and strain rates ranging from 0.001 s-1 to 10 s-1. The mechanical behavior during hot deformation was discussed on the basis of flow curves and hot processing maps. The microstructures were analyzed via scanning electron microscopy and electron backscatter diffraction. The relationship between deformation conditions and grain size after dynamic recrystallization was obtained. The results show that the flow stress and peak strain both increase with decreasing temperature and increasing strain rate. The hot deformation activation energy is approximately 631 kJ/mol, and a hot deformation equation is proposed. (Nb,V)N precipitates with either round, square, or irregular shapes are observed at the grain boundaries and in the matrix after deformation. According to the discussion, the hot working should be processed in the temperature range of 1050℃ to 1150℃ and in the strain rate range of 0.01 to 1 s-1.     

Microstructure, crystallography and nucleation mechanism of NANOBAIN steel

The microstructure of bainite ferrite in NANOBAIN steel transformed at different temperatures was investigated by scanning electron microscopy, transmission electron microscopy, electron back-scattered diffraction, and vickers hardness tester in detail. It is found that the average width of bainitic ferrite (BF) plates can be refined to be thinner with the reduction of temperature (473–573 K), and the bainitic ferrite plates can reach up to 20–74 nm at 473 K. Crystallographic analysis reveals that the bainitic ferrite laths are close to the Nishiyama-Wasserman orientation relationship with their parent austenite. Temperature shows a significant effect on the variant selection, and a decrease in temperature generally weakens the variant selection. Thermodynamic analyses indicates that the Lacher, Fowler and Guggenheim (LFG) model is more suitable than the Kaufman, Radcliffe and Cohen (KRC) model dealing with NANOBAIN steel at a low temperature range. The free energy change ΔGγ→BF is about ?1500 J·mol?1 at 473 K, which indicates that nucleation in NANOBAIN steel is the shear mechanism. Finally, the formation of carbon poor regions is thermodynamically possible, and the existence of carbon poor regions can greatly increase the possibility of the shear mechanism.     

Research of {0001} crystal orientation for magnesium alloys solidified in a fashion of cellular crystals

The magnesium alloy grew in a fashion of cellular crystals during the process of unidirectional solidification, and the {0001} crystal face orientation in the cast ingot of the magnesium alloy was studied. The theoretical model and methodology were set up, and a corresponding experiment was carried out to verify the theoretical analysis results. The experimental results indicate that the {0001} crystal face of magnesium crystals parallels to the width direction for the thin-plate cast ingot when the magnesium grows in a manner of cellular crystals. The separation angle between the {0001} crystal face of magnesium crystals and the vertical axis line of the cast ingot is about 62° for the circular column cast ingot, which distributes in cone-type. The theoretical analysis results are basically in agreement with the experimental ones of previous literatures and this paper.     

A rapid response photochromic diarylethene material for rewritable holographic data storage

A novel diarylethene,namely 4,5-(2,5-dimethyl thiophene) phthalimide,was synthesized and successfully introduced to rewritable holographic data storage.Upon the alternative illumination of UV and visible light(>400 nm),this compound underwent rapid,reversible inter-conversion between colorless open-ring isomer and yellow-green ring-closed form in both solution and polymethyl methacrylate(PMMA) film.Subsequently,we investigated the characteristics of volume homographic recording of the diarylethene-doped PMMA film(1 m thick).The maximum refractive index modulation(0.87‰) of the film during recording could be reached within just 120 s which gave the ability of fast recording.The high quality reconstruction after 50 write/erase cycles demonstrated its excellent fatigue-resistance and high resolution.All those results indicated that this molecule was a reliable fast write/erase holographic storage material.     

Prolyl 4-hydroxylation regulates Argonaute 2 stability

Human Argonaute (Ago) proteins are essential components of the RNA-induced silencing complexes (RISCs). Argonaute 2 (Ago2) has a P-element-induced wimpy testis (PIWI) domain, which folds like RNase H and is responsible for target RNA cleavage in RNA interference. Proteins such as Dicer, TRBP, MOV10, RHA, RCK/p54 and KIAA1093 associate with Ago proteins and participate in small RNA processing, RISC loading and localization of Ago proteins in the cytoplasmic messenger RNA processing bodies. However, mechanisms that regulate RNA interference remain obscure. Here we report physical interactions between Ago2 and the alpha-(P4H-alpha(I)) and beta-(P4H-beta) subunits of the type I collagen prolyl-4-hydroxylase (C-P4H(I)). Mass spectrometric analysis identified hydroxylation of the endogenous Ago2 at proline 700. In vitro, both Ago2 and Ago4 seem to be more efficiently hydroxylated than Ago1 and Ago3 by recombinant human C-P4H(I). Importantly, human cells depleted of P4H-alpha(I) or P4H-beta by short hairpin RNA and P4H-alpha(I) null mouse embryonic fibroblast cells showed reduced stability of Ago2 and impaired short interfering RNA programmed RISC activity. Furthermore, mutation of proline 700 to alanine also resulted in destabilization of Ago2, thus linking Ago2 P700 and hydroxylation at this residue to its stability regulation. These findings identify hydroxylation as a post-translational modification important for Ago2 stability and effective RNA interference.     

Heat treatment of novel low-carbon multi-alloyed anti-wear marine steel

A low-carbon anti-wear steel,multi-alloyed with Si-Cr-Mn-Al-Ni-Mo-(Nb,RE),was designed for vane pumps of ships. The novel cast steel after various heat treatments was characterized by microstructure observations and mechanical properties measurement in order to achieve an optimal process correlated with good abrasive resistance for a long marine service.Differential scanning calorimetry and hardness analyses deduced a complete austenitizing temperature of 1 000℃,based on the alloying element homogenizati...     

Molecularly imprinted polymer/graphene oxide modified glassy carbon electrode for selective detection of sulfanilamide

A novel sensitive electrochemical sensor based on a glassy carbon electrode(GCE) modified with molecularly imprinted polymer(MIP) and grapheme oxide(GO) was developed.The MIP/GO material was prepared by precipitation polymerization in the presence of sulfanilamide as template molecule.The MIP/GO based electrochemical sensor was characterized using scanning electron microscopy(SEM),cyclic voltammetry(CV),electrochemical impedance spectroscopy(EIS) and square wave voltammetry(SWV).The results indicated that the sensor exhibited good affinity and excellent electrochemical response for sulfanilamide.Under optimized conditions,the oxidation peak current intensity of sulfanilamide showed two linear dynamic ranges from 10 to 1000 ng mL~(-1),and the standard deviation was less than 5% using SWV method.The sensor displays good stability,reproducibility,and high sensitivity.It can be further applied to quantify sulfanilamide in milk.     

Electrochemical Method for Evaluating the Passivated State of Medical Stainless Steel 317L

The electrochemical behavior of the medical Stainless steel 317L which is used as in vivo fixation materials has been investigated at different passivated states in several candidate-testing solutions. The potentiodynamic scanning polarizaion technique was employed to measure the polarizaion curves of 317L in 0.9%NaCl solution at 37℃. The results showed that the electrochemical behavior in 0.9% NaCl solution at 37℃ and in 2% NaCl solotion at 30℃ can be better used to detect and evaluate passivated states and corrosion resistance of 317L. In addition,the pitting potential Eb can be used as a criterion and itS lower limit could be 0.85 V(SEC) for this system.