基于团簇式的GH2132高温合金成分协同变化关系

GH2132(A286)是析出强化型铁基高温合金,其含有多种合金化元素,为避免不合适的成分选择导致的综合性能失配,通过重点分析东北特钢提供的产品成分,解析国标成分区间的合理性,本文提出了一个更加合适的新成分标准形式。为此,引入“团簇加连接原子”结构模型,该模型将合金成分的结构载体表述为［中心-第一近邻］(连接原子)的团簇成分式形式。首先将合金化元素分为基体Fe、稳定奥氏体的(Ni,Mn)、稳定铁素体的(Cr,Mo,V,Si,Ti,Al)、以及不进入团簇式的(C,P,S,B)。通过分析国标规定的成分区间和实际合金成分,指出合金的实际成分区间远小于国标范围,并由16原子的成分式限定:Fe(8.5~9.0)±0.25(Ni,Mn)4±0.25(Cr,Mo,V,Si,Ti,Al)3~3.5。进而揭示了同类元素内部的质量百分比协同变化关系,即24.6≤Ni+Mn ≤28.0和17.4≤Cr+0.6Mo+V+1.7Si+1.1Ti+1.8Al≤20.4。由此更合理地限定Mn、Si元素成分区间,并对东北特钢的合金成分提供了改进建议。     

AC Potential-Dependent Concentration Variation and Domain Wall Pinning in Co1−x Zn x (x=0.4−0.5) Nanorods

The Co_1?x Zn _x (x=0.4?0.5) nanorods were synthesized via an AC electrochemical deposition method into anodized aluminum oxide (AAO) templates at different voltages ranging from 10 to 18 V, and nanorods of varying concentrations of Co and Zn were obtained. The characterization tools were used to examine different aspects of nanorods, e.g., shape, size, morphology, chemical composition, and magnetic behavior. Scanning electron microscope (SEM) images show that CoZn nanorods have length L=1μm and diameter d=50 nm. The grain size was calculated to be 25.4 nm using an X-ray diffraction (XRD) technique. The XRD also shows some other phases of ZnCoO. The M?H loops measured by a vibrating sample magnetometer (VSM) at room temperature show pure ferromagnetic behavior at all AC potentials. The nanorods show magnetic isotropic behavior due to strong magnetic interactions and presence of random nanorods. The potential-dependent coercivity H _c and saturation magnetization M _s show a non-linear curve which is explained on the basis of magnetic islands and domain wall pinning. This study is useful to tune the magnetic properties of nanorods by a simple and low-cost technique.     

Human Behavior Classification Using Geometrical Features of Skeleton and Support Vector Machines

Classification of human actions under video surveillance is gaining a lot of attention from computer vision researchers. In this paper, we have presented methodology to recognize human behavior in thin crowd which may be very helpful in surveillance. Research have mostly focused the problem of human detection in thin crowd, overall behavior of the crowd and actions of individuals in video sequences. Vision based Human behavior modeling is a complex task as it involves human detection, tracking, classifying normal and abnormal behavior. The proposed methodology takes input video and applies Gaussian based segmentation technique followed by post processing through presenting hole filling algorithm i.e., fill hole inside objects algorithm. Human detection is performed by presenting human detection algorithm and then geometrical features from human skeleton are extracted using feature extraction algorithm. The classification task is achieved using binary and multi class support vector machines. The proposed technique is validated through accuracy, precision, recall and F-measure metrics.     

Effect of aligning magnetic field on the magnetic and calorimetric properties of ferrimagnetic bioactive glass ceramics for the hyperthermia treatment of cancer

The magnetic and heat generating properties of the ferrimagnetic zinc-ferrite containing bioactive glass ceramics have been enhanced by aligning magnetic field, without any compositional or micro-structural changes in the material. The glass ceramics were heated to 600 °C and cooled in an aligning magnetic field of 1 T. Magnetically aligned samples were compared with the non-aligned samples. VSM measurements taken at 500 Oe showed that coercive force, remanance magnetization and hysteresis area increased for the aligned samples. This occurred because the aligning magnetic field setup an easy axis for the magnetic domains. After cooling, the domains were trapped and became stable along the direction of aligning field. Now stronger magnetic field was required to turn the domains away from their aligned positions. Thus magnetic properties were enhanced by the aligning magnetic field and it led to enhance the heat generation under magnetic induction furnace operating at 500 Oe and 60 kHz for 2 min. Data showed that maximum specific power loss and temperature increase after 2 min were 4.4 W/g and 6.3 °C respectively for the aligned sample of maximum zinc-ferrite crystalline content having pseudo single domain crystalline structure. The glass ceramics were immersed in simulated body fluid over weeks. FTIR, SEM and EDX results indicated the growth of precipitated Hydroxyapatite suggesting the bioactivity of the materials.     

Revealing the Synergy of Cation and Anion Vacancies on Improving Overall Water Splitting Kinetics

The exact understanding for each promotional role of cation and anion vacancies in bifunctional water splitting activity will assist in the development of an efficient activation strategy of inert catalysts. Herein, systematic first-principles computations demonstrate that the synergy of anion–oxygen and cation–manganese vacancies (V_O and V_Mn) in manganese dioxide (MnO₂) nanosheets results in abnormal local lattice distortion and electronic modulation. Such alterations enrich the accessible active centers, increase conductivity, enhance the water dissociation step, and favor intermediate adsorption–desorption, consequently promoting HER and OER kinetics. As proof of concept, robust electrocatalysts, MnO₂ ultrathin nanosheets doped with dual vacancies (DV–MnO₂) are obtained via a maturely chemical strategy. Detailed characterizations confirm the cation vacancies-V_Mn contribute to enhanced conductivity and anion vacancies-V_O enrich the active centers with optimized local electronic configurations, consistent with the simulative predictions. As expected, DV–MnO₂ exhibits exceptional bifunctionality with the strong assistance of synergetic dual vacancies which act as abundant “hot spots” for active multiple intermediates. Leading to a lower cell voltage (1.55 V) in alkali electrolyte is required to reach 10 mA cm⁻² for the overall water splitting system. These atomic-level insights on synergetic DV can favor the development of activating strategy from inert electrocatalysts.     

Thermo-responsive copolymer coated MnFe2O4 magnetic nanoparticles for hyperthermia therapy and controlled drug delivery

This study is about multifunctional magnetic nanoparticles surface-modified with bilayer oleic acid, and coated with a thermo-responsive copolymer poly(N-isopropylacrylamide-co-acrylamide) by emulsion polymerization, for controlled drug delivery and magnetic hyperthermia applications. Nanoparticles were loaded with anticancer drug doxorubicin into the copolymer chains at 25 °C. Composite nanoparticles (hydrated) of average diameter 45 nm were of core–shell structure having magnetic core of about 18 nm and shell was composed of organic compounds and water. Magnetic core was superparamagnetic lacking coercive force and remanance due to the pseudo-single domain nanostructure. Lower critical solution temperature (LCST) of the thermo-responsive copolymer was observed to be around 39 °C. Below this temperature, copolymer was hydrophilic, hydrated and swelled. But above LCST, copolymer became hydrophobic, dehydrated and shrank in volume. UV visible spectrophotometer was used to investigate the drug loading and releasing profile at different temperatures as well as under magnetic heating. There was almost absence of drug release at around 37 °C (normal body temperature). Drug was released at temperatures above LCST, which is significant for controlled drug delivery. Magnetic heat-generation was studied by exposing the magnetic fluid to alternating magnetic field of 7.2 kA m⁻¹ having frequency 70 kHz. A simple magnetic capturing system (simulating a blood vessel) was used to analyze the capturing of magnetic nanoparticles under various applied fields for drug targeting purpose.     

Context Based Adoption of Ranking and Indexing Measures for Cricket Team Ranks

There is an international cricket governing body that ranks the expertise of all the cricket playing nations, known as the International Cricket Council (ICC). The ranking system followed by the ICC relies on the winnings and defeats of the teams. The model used by the ICC to implement rankings is deficient in certain key respects. It ignores key factors like winning margin and strength of the opposition. Various measures of the ranking concept are presented in this research. The proposed methods adopt the concepts of h-Index and PageRank for presenting more comprehensive ranking metrics. The proposed approaches not only rank the teams on their losing/winning stats but also take into consideration the margin of winning and the quality of the opposition. Three cricket team ranking techniques are presented i.e., (1) Cricket Team-Index (ct-index), (2) Cricket Team Rank (CTR) and (3) Weighted Cricket Team Rank (WCTR). The proposed metrics are validated through the collection of cricket dataset, extracted from Cricinfo, having instances for all the three formats of the game i.e., T20 International (T20i), One Day International (ODI) and Test matches. The comparative analysis between the proposed and existing techniques, for all the three formats, is presented as well.