Effects of COOH~+ ion implantation on hemocompatibility of polypropylene

Carboxyl ion (COOH+) implantation was performed at 50 keV with different fluences for polypropylene. Hemocompatibility tests show that blood coagulation time and recalcification time of polypropylene were enhanced significantly with the increasing fluence. At the same time, the human endothelial cells grown on the surface of the implanted samples exhibited normal cellular growth and morphology. X-ray photoelectron spectroscopy and water contact angle analysis showed that COOH+ ion implantation rearranges chemical bonds and produces some new polar O-containing groups on the surface. The formation of polar functional groups, together with increase of roughness, induced an increase in hydrophilicity, which in turn improved the surface hemocompatibility of polypropylene.     

The modification behaviour for Si implanted PET

Polymeric solids have low density, high ability to form intricate shapes, versatile electronic properties and low manufacturing cost. However their uses are still limited by their inherent softness and unexpected dielectric properties. In order to enhance their electrical and mechanical properties, ion implantation techniques have been explored[1—3]. Recent studies have shown that ion implantation is very effective for improving surface properties of polymers such as surface hardness and wear…     

Nano-phases and corrosion resistance of C+Mo dual implanted steel

The corrosion resistance of C + Mo dual-implanted HI3 steel was studied using multi-sweep cyclic voltammetry. The phase formation conditions for corrosion resistance and its effects were researched. The super-saturation solid station solution of Mo+ and C+ atoms was formed in Mo + C dual implanted steel. Precipitate phase with nanometer size Fe2Mo, FeMo, MoC, Fe5C3 and Fe7C3 were formed in dual implanted layer. The passivation layer consisted of these nanometer phases. The corrosion resistance of the dual implanted layer was better than that of single Mo implantation. Jp of the Mo implanted sample is 0.55 times that of H13 steel. The corrosion resistance of the dual implantation was enhanced when ion dose increased. When the Mo+ ion dose was 6 × 1017/cm2 in the dual implantation, Jp of the dual implanted sample was only 0.11 times that in H13 steel. What is important is that pitting corrosion properties of dual implanted steel were improved obviously.     

Nanometer structure and conductor mechanism of polymer modified by metal ion implantation

Polyethylene terephthalate (PET) has been modified by Ag, Ti, Cu and Si ion implantation with a dose ranging from 1 × 1016 to 2 × 1017 ions/cm2 using a metal vapor vacuum arc (MEVVA) source. The electrical properties of PET have been improved by metal ion implantation. The resistivity of implanted PET decreased obviously with an increase in ion dose. The results show that the conductive behavior of a metal ion implanted sample is different from Si-implantation samples. In order to un-derstant the mechanism of electrical conduction, the structures of implanted layer were observed in detail by XRD and TEM. The nano carbon particles were dispersed in implanted PET. The nano metallic particles were built up in metallic ion implanted layers with dose range from 1 × 1016 to 1 × 1017 ions/ cm2. The nanometer metal net structure was formed in implanted layer when a dose of 2 × 1017ions/ cm2 is reached. Anomalous fractal growths were observed. These surface structure changes revealed conducting mechanism evo     

Experimental studies of N~+ implantation into CVD diamond thin films

The effects of N+ implantation under various conditions on CVD diamond films were analyzed with Raman spectroscopy, four-point probe method, X-ray diffraction (XRD), Rutherford backseattering spectroscopy (RBS), ultraviolet photoluminescence spectroscopy (UV-PL), Fourier transformation infrared absorption spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The results show that the N+ implantation doping without any graphitization has been successfully realized when 100 keV N+ ions at a dosage of 2 × 1016 cm-2 were implanted into diamond films at 550℃ . UV-PL spectra indicate that the implanted N+ ions formed an electrically inactive deep-level impurity in diamond films. So the sheet resistance of the sample after N+ implantation changed little. Carbon nitride containing C≡N covalent bond has been successfully synthesized by 100 keV, 1.2×1018 N/cm2 N+ implantation into diamond films. Most of the implanted N+ ions formed C≡N covalent bonds with C atoms. The others were free state nitroge     

Insights into the adsorption performance and mechanism of hydrated Ca ion on talc (0 0 1) basal surface from DFT calculation

The utilization of Ca ion as assistant depressant of CMC on talc has been widely reported. Thus, the study on the adsorption mechanism of Ca ion on talc surface is very crucial for understanding the performance of CMC on talc depression. In this paper, mechanism insights into hydrated Ca ion adsorption on talc (0 0 1) basal surface were creatively provided using DFT calculation. [Ca(H₂O)₆]²⁺ and [Ca(OH)(H₂O)₃]⁺ were determined as the effective hydrate components for Ca ion adsorption, and the top O site was the most favorable position for their adsorptions on talc surface. Furthermore, the adsorption mechanisms of [Ca(H₂O)₆]²⁺ and [Ca(OH)(H₂O)₃]⁺ on talc surface were found to be not the Ca—O chemical bond, but the hydrogen bonding formed by the H atom of the H₂O ligand and the surface O atom. H₂O acted like a bridge to connect them to the talc surface. Moreover, the hydrogen bonding was formed due to the hybridization of H 1s orbital with the O 2s, O 2p orbitals. Simultaneously, electrons transferred between the H atom and the surface O atom. This work provides theoretical insights into the Ca ion adsorption on talc surface, which can help deeply understand the talc flotation using CMC as depression.     

Investigation on the surface active sites variation of mineral dusts

Ｔｈｅｇｒｏｕｐｏｆｎａｔｕｒａｌｍｉｎｅｒａｌｄｕｓｔｓｒｅｌａｔｅｓｔｏｔｈｅｉｒｂｉｏｌｏｇｉｃａｌａｃｔｉｖｉｔｙａｎｄｃｏｎｔｒｏｌｓｔｈｅｉｒｆｅａｔｕｒｅａｎｄｃｏｎｔｒｉｂｕｔｉｏｎｏｆｓｕｒｆａｃｅａｃｔｉｖｅｓｉｔｅｓａｎｄｉｎｆｌｕ ｅｎｃｅｓｏｎｔｈｅｐｒｏｃｅｓｓｏｆｔｈｅｉｒｓｕｒｆａｃｅ/ｃｅｌｌｐｈｙｃｏ ｃｈｅｍｉｓｔｒｙ[1] .1　ＥｘｐｅｒｉｍｅｎｔａｌＴｈｅｓａｍｐｌｅｓｕｓｅｄｉｎｅｘｐｅｒｉｍｅｎｔａｌｗｅｒｅｆｉ ｂｒｏｕｓｂｒｕｃｉｔｅｆｒｏｍｔｈｅｓｏｕ…     

Plasma-enhanced Chemical Vapordeposition SiO2 Film after Ion Implantation Induces Quantum Well Intermixing

A method of QWI ( quantum well intermixing) realizing through plasma-enhanced chemical vapordepositiom (PECVD) SiO2 film following ion implantation was investigated. PECVD 200 nm SiO2 film after 160 keV phosphorus(P) ion implantation was performed to induce InP-based multiple-quantum-well (MQW) laser structural intermixing, annealing process was carried out at 780 ℃ for 30 seconds under N2 flue, the blue shift ofphotoluminescence (PL) peak related to implanted dose: 1 × 1011 , 1 × 1012, 1 × 1013 ,3 × 1013 , 7 × 1013 ion/ cm2 is 22 nm, 65 nm, 104 nm, 109 nm, 101 nm, respectively. Under the same conditions, by comparing the blue shift of PL peak with P ion implantation only, slight differentiation between the two methods was observed, and results reveal that the defects in the implanting layers generated by ion implantation are much more than those in SiO2 film. So, the blue shift results mainly from ion implantation. However , SiO2 film also may promote the quantum well intermixing.     

Extraction Difficulty of Lithium Ions from Various Crystal Planes of Lithium Titanate

To study the extraction difficulty of lithium ions from various crystal planes of Li₂TiO₃, according to the first principle, four representative crystal surfaces of Li₂TiO₃ (precursor), (-133), (-206), (002) and (-131), were selected to establish a model and to calculate the surface energy, bond length and population using Materials Studio 5.5 (MS 5.5). The results demonstrate that there is no direct relationship between the surface energy and the order of disappearance of the four diffraction peaks when lithium titanate is treated with hydrochloric acid, instead, the difficulty of Li⁺ extraction from various crystal faces corresponds to the Li-O bond strength. Lithium ion is easy to remove from (-133) and (-206) due to the relatively weak Li-O bond strength. In contrast, Li⁺ extraction requires a longer time for (002) and (-131).     

Property improvement of multilayer TiN/Ti films with C+ implantation

Using the MEVVA ion source, carbon ions have been implanted in TiN coatings deposited by multiarc ion plating. The Vickers microhardness of the C⁺-implanted TiN films increased with the increase in the ion flux and dose. X-ray diffraction (XRD) analysis showed that the TiC phases had been formed in the films. In addition, the films had the preferred growth orientations of TiN and TiC, both of which were (111) orientation after annealing at 500°C for 30 min. Auger electron spectra analysis indicated that C⁺-implanted profile was in typical Gaussian-like distribution in single films. The distribution with multipeaks of C atoms was obtained in multi-layer TiN/Ti. The possibility of the multilayer films (Ti(C,N)/TiN/Ti(C,N)/TiN and Ti(C,N)/TiC/Ti(C,N)/TiC) forming using the C-implanted TiN/Ti films is presented for the first time. Project supported by the National Natural Science Foundation of China and the “863” Hi-Tech Program of China.     

Preparation and antimicrobial ability of natural proous antibacterial materials

The liquid ion exchange method, solid salt melt method and dry-wet circulation method were used to prepare natural porous antimicrobial materials with natural minerals, such as zeolite, spilite, palygorskite and montmorillonite, respectively. Atomic absorption spectrum and X-ray diffraction analysis were carried out to investigate the effects of Ag⁺, Cu²⁺ and Zn²⁺ on antimicrobial abilities of natural porous minerals, and the effect of preparation method on ion exchange capacity of antimicrobial material, respectively. The results show that for the ion exchange capacity, clay mineral is higher than fibrous mineral, i. e. both zeolite and montmorillonite are higher; the antimicrobial ability of material with Ag⁺ is the best; the exchange capacities of materials with Cu²⁺ or Zn²⁺ are all higher, but the antimicrobial ability of Cu²⁺ is better than that of Zn²⁺. Foundation item: Project (40072020) supported by the National Natural Science Foundation of China; project (2001AA322070) supported by the National High Technology Research and Development Program of China     

Predicting the threshold values based on diffusion model of nitrite ions in reinforced concrete

The prediction model for inhibition effect of reinforced concrete was presented based on the Magge’s model when the concrete surface was brushed with nitrite solution. The influence of the amount of nitrite solution on inhibiting duration was also discussed through a simulation analysis when the amount of solution were 250 g/m², 500 g/m², 1000 g/m² and 1500 g/m², respectively. The experimental results confirm that nitrite ion can diffuse well in concrete to reach an effective mol ratio from the surface of the concrete to the surface of the reinforcement, and has an effective protection for the bars against corrosion. The higher the amount of solution, the better it will accelerate getting the threshold value of mol ratio on the surface of rebar, and retarding the time for loosing the effective threshold value of mol ratio. It helps to increase the tendency of inhibiting duration and prolong the life of reinforced concrete. The nitrite solution amount is used to predict the corrosion inhibiting duration of concrete that contains chloride salt.     

Molecular dynamics simulation of alkaline electrolyte diffusion in anion exchange membrane

During the operation of alkaline direct liquid fuel cells, the alkaline electrolyte is usually needed in the anode electrode to accelerate the electrochemical reaction kinetics of the liquid fuel. However, the crossover of the alkaline solution in the anode through the anion exchange membrane to the cathode can increase the transfer resistance of the oxygen in the cathode. In order to reduce the crossover of the alkaline solution, the diffusion process of the alkaline solution in the anion exchange membrane needs to be fully understood. In this work, interface models of anion exchange membrane-alkaline electrolytes are established based on the cell structure of the quaternary ammonium polysulfone (QAPS) membrane to simulate the dynamic process of the alkaline solution in the membrane. The effect of the type and the concentration of the alkaline solution on the transportation of the metal ions and OH⁻ in the membrane are studied. The results show that the agglomeration of Na⁺ is formed more easily than K⁺ in the interface model. Because of the strong interaction of Na⁺ on OH⁻, OH⁻ ions appear to be concentrated, resulting in that the diffusion coefficients of the metal ion and OH⁻ in the in Na⁺ solution are lower than those in the K⁺ solution. In addition, with the raised concentration of electrolyte solution, the aggregation degrees of the metal ions and OH⁻ can be increased, which means an enlarged mass transfer resistance of the components. Furthermore, by adding a polytetrafluoroethylene (PTFE) layer on the QAPS membrane, the distribution of metal ions tends to be concentrated, and the number of hydrophilic channels in the QAPS membrane is reduced, which significantly increases the alkali resistance of the anion exchange membrane.

     

Ca2+对SiO2-BSA混合体系膜污染行为的影响

为研究Ca²⁺对SiO₂-BSA混合污染物膜污染行为的影响,针对SiO₂与牛血清蛋白(BSA)共存体系,在不同Ca²⁺浓度下,使用原子力显微镜测定各污染物与聚偏氟乙烯(PVDF)超滤膜及各污染物之间的作用力,结合膜污染实验,探讨Ca²⁺对SiO₂-BSA混合污染物膜污染行为的影响.结果表明:随着Ca²⁺浓度的增大,SiO₂-BSA引起的膜污染逐渐减小,主要是因为Ca²⁺改变了SiO₂-BSA混合体系中各污染物与膜及污染物之间的相互作用力.针对污染物与膜之间的相互作用力,Ca²⁺的加入触发了PVDF膜与BSA及SiO₂之间的水合排斥力,从而削弱BSA在膜表面的吸附累计速率,有效减缓了运行初期的膜污染速率;针对污染物之间的作用力,Ca²⁺浓度的增加使得SiO₂-SiO₂及SiO₂-BSA之间作用力增大,从而导致污染物团聚形成大尺寸聚集体,在膜面形成松散多孔的污染层,进而伴随着膜污染速率以及污染幅度的减小.     

The mechanism of ground granulated blastfurnace slag preventing alkali aggregate reaction

Three different methods were applied to study the alkali content of gelpores in cement. In the closed system, the concentration of K⁺, Na⁺ and OH⁻ have not reduced with the increase of age. In the open system, the diffusion and transferring of K⁺ and Na⁺ towards free space leads to the decrease of total alkali content. In the micro-analysis system, the contents of K⁺ and Na⁺ in the first hydrated layer of ground granulated blastfurnace slag (GBFS) are very low, while the contents of calcium and magnesium are relatively high. This phenomenon shows that the mechanism of GBFS preventing alkali aggregate reaction (AAR) is: when GBFS is dissolved by alkali medium, SiO₂ and Al₂O₃ are dissolved into the cement matrix, then around GBFS particles form reaction rings rich in Ca²⁺ and Mg²⁺, and the C-S-H gel of positive charges formed in the area repulses K⁺ and Na⁺, which are forced to transfer to the mortar’s matrix, pore or mortar sample surface. The transferred K⁺ and Na⁺ form alkali gel products with other dissolved ions, then become evenly distributed in the mortar sample and react with Ca(OH)₂ in pore solutions to form (Na,K) _x−2z ·zCa·(SiO₂)_y·(OH)_x gel products; and thus changes the AAR gel products’ structure. The gel products will not expand, and so they can delay expansion destruction.     

Analysis of Dynamic Tensile Process of Fiber Reinforced Concrete by Acoustic Emission Technique

The fiber reinforced concrete has good dynamic mechanical properties. But corresponding research lacks the dynamic damage characteristics of the polypropylene fiber (fiber of low elastic modulus) and steel fiber (fiber of high elastic modulus) reinforced concrete under medium strain rate (10^-6 s^-1-10^-4 s^-1). In order to study the effect of strain rate on the damage characteristics of fiber reinforced concrete during the full curve damage process, the real time dynamic acoustic emission (AE) technique was applied to monitor the damage process of fiber reinforced concrete at three strain rates. The AE wavelet energy spectrum in ca8 frequency band and average AE peak frequency at three strain rates were analyzed. With the accumulation of damage, the AE wavelet energy spectrum in ca8 frequency band increased first and then decreased, and the average AE peak frequency increased gradually. With the increase of strain rate, the AE wavelet energy spectrum in ca8 frequency band and average AE peak frequency decreased gradually. The polypropylene fiber content has more obvious effect on the Dynamic increase factor (DIF) of the peak stress than the steel fiber content. The theoretical basis was provided for the monitoring of dynamic damage of fiber reinforced concrete based on the AE technique.     

Plasma-based ion implantation of nitrogen into Ti-6Al-4V: effect of implantation time and pre-or post-implantation aging on nitrogen distribution and microhardness

0　ＩＮＴＲＯＤＵＣＴＩＯＮＰｌａｓｍａ ｂａｓｅｄｉｏｎｉｍｐｌａｎｔａｔｉｏｎ (ＰＢＩＩ)ｏｆｎｉｔｒｏｇｅｎｉｓｒｅｐｏｒｔｅｄｔｏｂｅａｖｅｒｙｃｏｓｔ ｅｆｆｅｃｔｉｖｅｔｅｃｈｎｉｑｕｅｆｏｒｓｕｒｆａｃｅｍｏｄｉｆｉｃａｔｉｏｎｏｆＴｉ 6Ａｌ 4Ｖａｌｌｏｙ[1～ 4 ] .Ｆｕｔｕｒｅｗｏｒｋｒｅｍａｉｎｓｔｏｃｏｎｃｅｎｔｒａｔｅｏｎｄｅｔｅｒｍｉｎｉｎｇｔｈｅｅｘａｃｔｍｅｃｈａｎｉｓｍｏｆｔｈｅｔｅｃｈｎｉｑｕｅｗｈｅｎａｐｐｌｉｅｄｔｏｔｈｅａｌｌｏｙ[2 ] .Ｆｏｒｃｏｎｖｅｎｔｉｏｎａ…     

掺硼金刚石薄膜电极电化学氧化对铜绿微囊藻的生长抑制

阳极材料采用掺硼金刚石薄膜板状电极,研究了电化学氧化中电流密度、电解时间、pH、氯离子浓度、硫酸根离子浓度对铜绿微囊藻生长抑制的影响,以及电解前后藻细胞形态的变化。结果表明,4个影响因素对铜绿微囊藻生长抑制效果显著。抑藻效果随电流密度、电解时间的增加而增加,电流密度为17 mA/cm²时藻细胞出现破裂、细胞内物质流出的现象,抑藻效果较好;当电解时间为20 min时,可完全抑制藻细胞生长;再增大电解时间,对抑藻效果无明显促进作用,初始pH在中性及酸性条件下可完全抑制藻细胞生长。抑藻效果与溶液中氯离子、硫酸根离子浓度成正相关,当溶液中氯离子浓度为6 mg/L时,可完全抑制藻细胞生长;无氯离子时,藻细胞在4 d后出现继续增长现象。     

Determination of the entropy change for electrode reaction and dilute enthalpy of some ions by thermo-eletrochemical technology

Based on thermo-electrochemical equation for an electrode reaction, the entropy change of it can be obtained by the thermo - electrochemical technology (TECT). The entropy changes of Fe (CN) ₆ ⁻³ /Fe (CN) ₆ ⁻⁴ , H⁺/H₂(P⁰), Cu⁺²/Cu and Zn⁺²/Zn electrode reaction systems and the dilute enthalpies of the H⁺, Cu²⁺ and Zn²⁺ ions under the ion concentrations studied have been determined by a specially designed thermo-electrochemical equipment. The enthalpy change and entropy change for the five systems at unlimitedly diluted concentrations agree well with the literature. Project supporterd by the National Natural Science Foundation of China Synopsis of the first author Fang Zheng, Ph. D. and professor, born in April 1944, majoring the metallurgical thermodynamics and thermoelectrochemistry, supervised and participated in three projects supported by the National Natural Science Fundation of China and some other projects. More than 70 academic papers have been published.     

Influence of surface roughness on flotation kinetics of quartz

Surface roughness of quartz particles was determined by measuring the specific surface area of particles. The wettability characteristics of particles were determined by measuring the flotation rate using a laboratory flotation cell. Experimental results show that the rod mill product has higher roughness than the ball mill product. For the particles with larger surface roughness, the flotation kinetics constant is also higher. Finally, empirical relationships between surface roughness (r) and the flotation kinetics constant (k) of quartz particles as k=A+Br+Cr ^0.5lnr+D/lnr+E/r and k=A+Br are presented, in which A, B, C, D and E are constants related to experimental conditions and mineralogical properties of mineral.