PVC自增塑和阻燃抑烟力化学技术取得突破

由中国科学院院士、四川大学教授徐僖主持研究的用于聚氯乙烯(PVC)自增塑和阻燃抑烟的力化学技术,通过了四川省科技厅组织的专家鉴定。这意味着PVC行业可望迎来质的飞跃,将对化学建材的发展产生深远的影响。这项成果采用高分子力化学新技术合成新型化工助剂,通过力化学新技术改变PVC微晶结构。

机械力化学法制备氯化锌法活性炭及其性能表征

研究利用机械力化学技术制备了性能良好的活性炭。采用Central Composite Design中心复合设计和响应面分析,对影响活性炭碘吸附值的主要影响因素进行多项回归模型建立和参数优化,并通过低温液氮(N2/77 K)吸附测定较优条件下制备的活性炭的比表面积、孔容及孔径分布。结果表明,利用氯化锌为活化剂的机械力化学技术制备活性炭的较优工艺条件为:氯化锌与绝干木屑的质量之比(锌屑比)值3.00,研磨时间10 min,活化温度584℃,活化时间2.5 h,此条件下制备的活性炭碘吸附值为1 262.47 mg/g。

固体废物有价资源机械力化学清洁提取技术的研究进展

有价资源是固体废物循环利用的主要经济驱动力之一,而有价资源的清洁提取一直是固体废物资源化领域的研究重点。简述了机械力化学技术的反应原理,通过文献计量形式重点呈现了机械力化学技术在固体废物有价资源清洁提取方面的研究动态。针对机械力化学技术在多源固体废物,如电子废物、废汽车催化剂、飞灰、含金废渣等有价资源清洁提取方面的研究进展进行了总结和分析,并系统讨论了该技术应用于固体废物有价资源清洁提取的产业优势和技术限制。结果显示,机械力化学技术适用于固体废物中有价金属的清洁提取与绿色再生,而能量利用及转化问题限制了该技术目前的进一步工业化应用。随着研究的持续深入和配套产业的不断进步,机械力化学技术有望成为新一代的固体废物有价资源清洁提取及绿色再生技术。

PVC可望迎来质的飞跃

近日,一项拥有自主知识产权的尖端技术——由中国科学院院士、四川大学教授徐僖主持研究的“用于聚氯乙烯(PVC)自增塑和阻燃抑烟的力化学技术”,通过了四川省科技厅组织的专家鉴定。 这标志着在采用高分子力化学新技术合成新型聚氯乙烯加工助剂方面取得突破。 专家十分看好这一原创性成果。

Bovine Serum Albumin (BSA) Microspheres Containing Methotrexate (MTX) I.Pharmaceutical Aspects

Microspheres Ⅰ,Ⅱ and Ⅲ were produced by emulsion technique.Microsphere I was solidified by glutaraldehyde crosslinking,microsphere Ⅱ was solidified by glutaraldehyde crosslinking and further treated with glycine solution and microsphere Illwas solidified by heating denaturation only.The results showed that the microsphere diameter produced by cross[inking was bigger than that prepared by heating.The microsphere Ⅱ had higher hydrophilicity than Microsphere I had.The methotrexate (MTX) contents in microspheres Ⅰ and Ⅱ were 2.73±0.053%,2.87±0.119% respectively. microsphere Ⅲ was only blank microspheres with MTX adsorbed on their surfaces.In vitro release studies,microspheres I and I have maintained sustained release of MTX till the next day,it was found that the drug releases from microspheres Ⅰ and Ⅱ were governed by Higuchi diffusion law.

Effects of Surface Etch Hole Fault on the Velocity Field in Microchannel Reactors

Microchannel reactors are commonly used in micro-chemical technology. The performance of microreactors is greatly affected by the velocity field in the microchannel. The flow field is disturbed by the cylindrical etch holes caused by air dust on the microchannel surface during its processing procedure. In this approach, a two-dimensional computational fluid dynamics （CFD） model is put forward to study the effect of etch holes on flow field. The influenced area of single or two concave etch holes is studied for the case of laminar flow. The hole diameter, the Reynolds number and the distance between the center of holes are found to have influences on the flow field. Numerical results indicate that the effects of etch hole on the flow field should be evaluated and the way of choosing the economic class of cleanroom for microreactor manufacture is presented.

Simulation of the Clustering Phenomenon in a Fast Fluidized Bed: The Importance of Drag Correlation

Drag force is a key parameter in the numerical modeling of gas-particle flow in circulating fluidized beds. The reliability of current drag force correlations over the regime of fast fluidization has, however, not been thoroughly investigated. In this article, a drag force correlation accounting for the clustering effects for Geldart A particles is used to simulate the behaviors typical of fast fluidization, including dynamic evolution of clusters as well as time- averaged axial and lateral voidage profiles. Diverse images of clusters are captured and the time-averaged profiles of voidage are shown to be in quantitative agreement with the present empirical correlation. The results based on different constitutive correlations of drag force show the importance of the choice of drag force in modeling fast-fluidized beds. This drag force correlation, based on a simple averaging assumption, could give some basic insights about the magnitude of the drag reduction.

Treatment of Phenol Wastewater Using High Gravity Electrochemical Reactor with Multi-concentric Cylindrical Electrodes

A novel high gravity electrochemical reactor with multi-concentric cylindrical electrodes was used in the electrochemical treatment of 5 000 mg/L phenol-containing wastewater at a petrochemical plant, which can operate continuously and process in a large scale. The results show that the high gravity technology used in electrochemical treatment of phenol-containing wastewater can shorten the electrolysis time, decrease the electrolysis voltage, and reduce the energy consumption. The COD removal efficiency was high in the high-gravity field, and reached up to about 48%, which was about 2 times the value achieved in the normal gravity field at a processing capacity of 6 L, a high gravity factor of 80, a voltage of 12 V, an electrolysis time of 40 min, and a wastewater flowrate of 80 L/h.

Kinetic Modeling of the Photocatalytic Degradation of Methyl Orange by Supported TiO2

The photocatalytic degradation of methyl orange （MO） in UV/Supported-TiO2 system was investigated and a kinetic model was presented. The experimental results show that the photocatalytic degradation rate is favored by high concentration of dye in solution and is enhanced by the solution temperature. A simple kinetic model has been proposed which can describe the discoloration process in an adequate way. The calculated results obtained were in good agreement with experimental data. The model predicts the concentration of MO during the photocatalytic degradation process.

Microstructure,mechanical properties and corrosion performance of selective laser melting Ti/GNPs composite with a porous structure

In this study,nano-graphene reinforced titanium matrix composites(GNPs/Ti)with a honeycomb porous structure were fabricated by selective laser melting(SLM).The effects of graphene on the microstructure,mechanical properties and corrosion performance of the SLM GNPs/Ti were systematically investigated.Results of microstructure characterization show that:1)the density of the SLM GNPs/Ti was improved as compared to that of the SLM Ti;2)abundant TiC particles were formed in the SLM GNPs/Ti.The hardness and compressive strength of the composite increased by 90%(from HV 236 to HV 503)and 14%(from 277 MPa to 316 MPa),respectively,attributed to the uniformly distributed TiC and fine GNPs in the Ti matrix.Electrochemical tests reveal that the corrosion current density of the SLM GNPs/Ti is only 0.328μA/cm^(2),that is about 25%less than that of the SLM Ti.The results indicate that the incorporation of nano-graphene is a potential method to strengthen the Ti by SLM.

Technological conditions and kinetics of leaching copper from complex copper oxide ore

The kinetic behavior of leaching copper from low grade copper oxide ore was investigated. The effects of leaching temperature, H2SO4 concentration, particle size of crude ore and agitation rate on the leaching efficiency of copper were also evaluated. And the kinetic equations of the leaching process were obtained. The results show that the leaching process can be described with a reaction model of shrinking core. The reaction can be divided into three stages. The first stage is the dissolution of free copper oxide and copper oxide wrapped by hematite-limonite ore. At this stage, the leaching efficiency is very fast （leaching efficiency is larger than 60%）. The second stage is the leaching of diffiuent copper oxides, whose apparent activation energy is 43.26 kJ/mol. During this process, the chemical reaction is the control step, and the reaction order of H2SO4 is 0.433 84. The third stage is the leaching of copper oxide wrapped by hematite-limonite and silicate ore with apparent activation energy of 16.08 kJ/mol, which belongs to the mixed control.

Can coordination variability identify performance factors and skill level in competitive sport? The case of race walking

Background:Marginal changes in the execution of competitive sports movements can represent a significant change for performance success.However,such differences may emerge only at certain execution intensities and are not easily detectable through conventional biomechanical techniques.This study aimed to investigate if and how competition standard and progression speed affect race walking kinematics from both a conventional and a coordination variability perspective.Methods:Fifteen experienced athletes divided into three groups(elite,international,and national) were studied while race walking on a treadmill at two different speeds(12.0 and 15.5 km/h).Basic gait parameters,the angular displacement of the pelvis and lower limbs,and the variability in continuous relative phase between six different joint couplings were analyzed.Results:Most of the spatio-temporal,kinematic,and coordination variability measures proved sensitive to the change in speed.Conversely,non-linear dynamics measures highlighted differences between athletes of different competition standard when conventional analytical tools were not able to discriminate between different skill levels.Continuous relative phase variability was higher for national level athletes than international and elite in two couplings(pelvis obliquity—hip flex/extension and pelvis rotation—ankle dorsi/plantarflexion) and gait phases(early stance for the first coupling,propulsive phase for the second) that are deemed fundamental for correct technique and performance.Conclusion:Measures of coordination variability showed to be a more sensitive tool for the fine detection of skill-dependent factors in competitive race walking,and showed good potential for being integrated in the assessment and monitoring of sports motor abilities.

The Role of Institutional Investors in the Evolutionary Dynamics of Agro-food Enterprises

The research topic is the one of public finance company whose core business is focused to support investment projects to overcome enterprises technological and structural gap. The research question is： If and how a public finance company is able to create and favor value creation processes sustainability for agro-food enterprises, highlighting the positive emerging externalities for different categories of stakeholders. They have results with particular evidences allow comparisons between the private investments and the support of institutional public investors. In such perspective, the mode of disbursement of soft loans and investment operations made by a public financing company will be examined. The methodological approach used, following a deductive-inductive perspective, is based on the ease study. Such technique able to formulate theories about a little known phenomena in their context, allows the study of recent events on which the researcher has little control. To this, a qualitative analysis on both primary and secondary data adds. From data analysis, it resulted that the Institute of Agribusiness Development （ISA） initiatives facilitated, just for example, the technological innovation of production department and consequent production capacity, the acquisition of production assets for row material processing and optimization of internal logistics, through an innovative automated warehouse. As a result, the case study finds sustainability at multiple levels reached by the activities promoted by ISA and the subsequent co-creation of value for stakeholders involved, small agro-food businesses innovation, and/or internationalization processes. As long as practical implications are concerned, such highlight the importance and the need for public and private institutions in their effort to continue to invest in projects to support the economy of the country. The originality of the paper lies in the proposed interpretation of more integrative paradigms （viable system approach, sustainability, and, value creation）, analyzing a financial institution for the development of the Italian food industry. At the same time, authors stress the research limit that is the analysis of the input of only one organization and consequent limited data in quantity and time span.

Stablility and Size Control of Silver Nanoparticles by Electrochemical Method

Silver nanoparticles （Ag-NPs） were prepared using an electrochemical technique. The optical properties were measured by absorption spectroscopy. The dimension of the prepared nanoparticles as estimated by the Atomic Force Microscope （AFM）, was 91.57 nm. This reaserch effort proposes a mechanism for reducing the size of silver nanoparticles by adding the hydrogen peroxide （H202）, and protecting the silver nanoparticle to inhibit agglomeration by adding PVP polymer.