A new cyclometalated iridium(IlI) complex Ir(DPP)3 (DPP=2,3-diphenylpyrazine) was prepared by reaction of DPP with iridium trichloride hydrate under microwave irradiation. The structure of the complex was confir...A new cyclometalated iridium(IlI) complex Ir(DPP)3 (DPP=2,3-diphenylpyrazine) was prepared by reaction of DPP with iridium trichloride hydrate under microwave irradiation. The structure of the complex was confirmed by elemental analysis, ^1H NMR, and mass spectroscopy. The UV-Vis absorption and photoluminescent properties of the complex were investigated. The complex shows strong ^1MLCT (singlet metal to ligand charge-transfer) and aMLCT (triplet metal to ligand charge-transfer) absorption at 382 and 504 nm, respectively. The complex also shows strong photoluminescence at 573 nm at room temperature. These results suggest the complex to be a promising phosphorescent material.展开更多
Red-emission (Y0.95Eu0.05)2O3 submicron spheres and microplates were selectively obtained via hydrothermal precursor synthesis (150 °C, 12 h) followed by calcination at 1000 °C. Characterizations of the ...Red-emission (Y0.95Eu0.05)2O3 submicron spheres and microplates were selectively obtained via hydrothermal precursor synthesis (150 °C, 12 h) followed by calcination at 1000 °C. Characterizations of the products were carried out by combined means of XRD, FT-IR, FE-SEM and PL analysis. The precursors could be modulated from basic-carbonate submicron spheres to normal carbonate microplates by increasing the molar ratio of urea to Y+Eu from 10 to 40-100. The resultant oxides largely retain their respective precursor morphologies at 1000 °C, but morphology confined crystal growth was observed for the microplates, yielding more enhanced exposure of the (400) facets. Both the (Y0.95Eu0.05)2O3 spheres and microplates exhibit nearly identical positions of the PL bands and similar asymmetry factors of luminescence [I(5D0→7F2)/I(5D0→7F1), ~11] under 250 nm excitation, but the microplates show a significantly strong red emission at ~613 nm ( ~1.33 times that of the spheres) owing to their larger particle size and denser packing of primary phosphor crystallites.展开更多
In recent years, production of engine fuels and energy from biomass has drawn much interest. In this work, we conducted a novel integrated process for the preparation of bio-hydrogen and bio-fuels using lignocellulosi...In recent years, production of engine fuels and energy from biomass has drawn much interest. In this work, we conducted a novel integrated process for the preparation of bio-hydrogen and bio-fuels using lignocellulosic biomass pyrolysis-oil (bio-oil). The process includes (i) the production of bio-hydrogen or bio-syngas by the catalytic cracking of bio-oil, (ii) the adjustment of bio-syngas, and (iii) the production of bio-fuels by ole nic polymerization (OP) together with Fischer-Tropsch synthesis (FTS). Under the optimal conditions, the yield of bio-hydrogen was 120.9 g H2/(kg bio-oil). The yield of hydrocarbon bio-fuels reached 526.1 g/(kg bio-syngas) by the coupling of OP and FTS. The main reaction pathways (or chemical processes) were discussed based on the products observed and the catalyst property.展开更多
While conventional wastewater treatments for urban effluents are fairly routine and have proved highly effective,industrial wastewater requires more complex and specific treatments.This paper provides a technological ...While conventional wastewater treatments for urban effluents are fairly routine and have proved highly effective,industrial wastewater requires more complex and specific treatments.This paper provides a technological strategy for removal of recalcitrant contaminants based on a hybrid treatment system.The model effluent containing a binary mixture of synthetic dyes is treated by a combination of a preliminary physicochemical stage followed by a biological stage based on ligninolytic enzymes produced by Phanerochaete chrysosporium.This proposal includes biosorption onto peat as pretreatment,which decreases the volume and concentration to be treated in the biological reactor,thereby obtaining a completely decolorized effluent.The treated wastewater can therefore be reused in the dyeing baths with the consequent saving of water resources.展开更多
Plastic pipes reinforced by cross helically wound steel wires (PSP), which have exhibited excellent mechanical performance, consist of inner polyethylene (PE) layer, winding layer and outer PE layer. The winding layer...Plastic pipes reinforced by cross helically wound steel wires (PSP), which have exhibited excellent mechanical performance, consist of inner polyethylene (PE) layer, winding layer and outer PE layer. The winding layer is composed of two monolayers where steel wires are cross helically wound. An analytical procedure is developed to predict the short-term burst pressure of PSP as the monolayer is assumed to be elastic and orthotropic. The 3D anisotropic elasticity and Maximum Stress Failure Criterion are employed in the formulation of the elasticity problem. Good agreement between the theoretical results and the experimental data shows that the proposed approach can well predict the short-term burst pressure of PSP.展开更多
Bipolar plates for proton exchange membrane fuel cell (PEMFC) where polymer is used as binder and graphite is used as electric filler were prepared by means of compression molding technology. Study on the effects of g...Bipolar plates for proton exchange membrane fuel cell (PEMFC) where polymer is used as binder and graphite is used as electric filler were prepared by means of compression molding technology. Study on the effects of graphite particle size and shape on the bipolar plate performance, such as electrical conductivity, strength, etc. showed that with decrease of graphite particle size, bulk electrical conductivity and thermometric conductivity decreased, but that flexural strength was enhanced. After spherical graphite occurrence in flake-like form, the flexural strength of the bipolar plate was enhanced, electrical conductivity increased but thermal conductivity decreased in direction paralleling pressure direction, and both electrical conductivity and thermometric conductivity reduced in direction perpendicular to pressure direction.展开更多
A kind of nanokaolin powder with a thickness of 20-50nm and an average diameter of 300nm is produced through combined procedure of purification, delamination, surface modification and pulverization. The application ex...A kind of nanokaolin powder with a thickness of 20-50nm and an average diameter of 300nm is produced through combined procedure of purification, delamination, surface modification and pulverization. The application experiments in butadiene rubber (BR), ethylene-propylene diene methylene (EPDM), and natural rubber (NR) indicates that this nano-kaolin powder material is much better than precipitated silica in reinforcement, while in styrene-butadiene rubber (SBR) it is close to precipitated silica. Nanokaolin is of superiority in elasticity, elongation at break, anti-flexure property.展开更多
Seven novel fluorescent coumarin derivatives were synthesized from 7-diethylamino-4-chloro-3-formyl-coumarin. The spectra of absorption, excitation and emission were dependent not only on the structures and also on th...Seven novel fluorescent coumarin derivatives were synthesized from 7-diethylamino-4-chloro-3-formyl-coumarin. The spectra of absorption, excitation and emission were dependent not only on the structures and also on the concentration of dyes. The PPP-MO predictions can only be consistent with the spectra in dilute solutions.展开更多
The pore constitution and tortuosity factor of porous TiAl intermetallic were studied on the basis of the variation behavior of pore structure parameters and the discrete particle model. The pore formation mechanism o...The pore constitution and tortuosity factor of porous TiAl intermetallic were studied on the basis of the variation behavior of pore structure parameters and the discrete particle model. The pore formation mechanism of porous TiAl is mainly ascribed to three aspects: the clearance space in green compact, the diffusive pores in the reaction process and the phase transition pores, resulting in the open porosities of 5.6%, 42.9% and 1.3%, respectively. According to the Hagen-Poiseuille equation, the tortuosity factor of porous TiAl is determined in the range of 1.3-2.2. Based on the discrete particle model and the variation rule of the tortuosity factor, the tortuosity factor depends mainly on the parameters of fabrication constant, particle shape factor, clearance distance and powder particle size. The quantitative relationships among them have been established, which can be used as the basis for adjusting the pore structure of porous intermetallics.展开更多
K2FeO4 powders were synthesized by the ex-situ and in-situ electrochemical methods, respectively, and characterized by infrared spectrum (IR), scanning electron microscopy (SEM), X-ray powder diffraction (XRD) a...K2FeO4 powders were synthesized by the ex-situ and in-situ electrochemical methods, respectively, and characterized by infrared spectrum (IR), scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and BET. Their electrochemical performances were investigated by means of galvanostatic discharge and electrochemi-cal impedance spectroscopy (EIS). The results of physical characterization showed that the two samples have simi-lar structural features, but their surface morphologies and oriented growth of the crystals are different, which results in smaller specific surface area and lower solubility of the ex-situ electrosynthesized K2FeO4 sample. The results of discharge experiments indicated that the ex-situ electrosythesized K2FeO4 electrode has much larger discharge ca-pacity and lower electrode polarization than the in-situ electrosynthesized K2FeO4 electrode. It was found from the results of EIS that lower electrochemical polarization might be responsible for the improvement on the discharge performance of the ex-situ electrosynthesized K2FeO4 electrode.展开更多
Permacol mesh has shown promise when used in abdominal wall repair,especially in the presence of a contaminated surgical field.This biomaterial,derived from porcine dermis collagen,has proposed advantages over synthet...Permacol mesh has shown promise when used in abdominal wall repair,especially in the presence of a contaminated surgical field.This biomaterial,derived from porcine dermis collagen,has proposed advantages over synthetic materials due to increased biocompatibility and reduced foreign body reaction within human tissues.However,we present a case report describing a patient who displayed rejection to a Permacol mesh when used in the repair of abdominal wound dehiscence following an emergency laparotomy.Review of the English language literature using PubMed and Medline, showed only two previously published cases of explantation of Permacoldue to sepsis or wound breakdown. The authors believe this is the first case of severe foreign body reaction leading to rejection of Permacol.Both animal and human studies show conflicting evidence of biocompatibility.There are several reports of successful use of Permacolto repair complex incisional herniae or abdominal walls in the presence of significant contamination.It appears from the literature that Permacolis a promising material,but as we have demonstrated,it has the potential to evoke a foreign body reaction and rejection in certain subjects.展开更多
Ccanposites are common material constructions for high-tech use now. Mechanical properties of woven reinforced composites are influenced by voids inside the structure. Voids could be classified to the two sections. Lo...Ccanposites are common material constructions for high-tech use now. Mechanical properties of woven reinforced composites are influenced by voids inside the structure. Voids could be classified to the two sections. Long and thin cracks are more dangerous than pores. It is important to find relations between preparation and place of occurrence of voids. This paper classifies defects according to rise mechanism, point of occurrence, orientation, size and affect to the properties. Image analysis was used for observing samples. Future work would be oriented not only to observing real samples, bet also to calculate mechanical properties frwn real and ideal structures in 3D woven reinforced composites.展开更多
In this study, a new zirconium-mediated cycloaddition for preparing dibenzosilole derivatives was developed using siliconbridged diynes and electron-withdrawing alkynes as starting materials. The preparation of silico...In this study, a new zirconium-mediated cycloaddition for preparing dibenzosilole derivatives was developed using siliconbridged diynes and electron-withdrawing alkynes as starting materials. The preparation of silicon-bridged diynes from 1-bromide-2-iodobenzene, terminal alkynes, and dimethyldichlorosilane was also studied. Unlike in the previous synthesis methods, much higher yields of electron-withdrawing group-substituted dibenzosilole derivatives were obtained. In addition, a new synthesis strategy for preparing benzonaphthosilole derivatives using internal alkynes, 1,4-dibromobenzene, and electron-withdrawing alkynes as starting materials is proposed. Compared with previous methods, alkyl, phenyl, and electron-withdrawing groups can be successfully introduced onto aromatic rings, and the positions of these substituents can be easily controlled. The cycloaddition reactions for dibenzosilole and benzonaphthosilole derivatives are highly efficient one-pot processes, and the raw materials are available and easily prepared. Using these new methods, a series of novel multisubstituted dibenzonsilole and benzonaphthosilole derivatives were obtained effectively.展开更多
Synthetic dyes are commonly used for graphite depression in poly-metallic flotation circuits; however,these dyes can be very expensive. The aim of this study is to evaluate performance of certain low-cost alternative ...Synthetic dyes are commonly used for graphite depression in poly-metallic flotation circuits; however,these dyes can be very expensive. The aim of this study is to evaluate performance of certain low-cost alternative depressants for a complex lead-zinc(Pb-Zn) ore rich in graphite(Gr-C) on a conventional mini pilot-scale flotation circuit. The reagents used were commercial and industrial grade starch; agro-based waste-sugarcane bagasse and charred(burnt) bagasse powder. The primary evaluation criteria were quality(grades) of lead and zinc concentrates, their recoveries(%), and graphite rejection(%) in the tails.Benchmark tests using nigrosine as graphite depressant showed 94.3% rejection of Gr-C. The results with commercial starch were found as effective with 93.8% graphite rejection. Furthermore, bagasse powder showed potential in improving product quality(36.4% and 65.6% Pb grade and recovery) with an intermediate effectiveness in graphite rejection(85.6%). The order of effectiveness in Gr-C rejection follows nigrosine % commercial starch > bagasse > industrial starch > charred bagasse. In addition, the effect these depressants on silver(byproduct) grade and recovery was also investigated.展开更多
Recent studies show an increase in the population of beavers, nutria and other rodents in vast regions of central Europe over the last 15 years. Unfortunately, this caused in many instances considerable damage on larg...Recent studies show an increase in the population of beavers, nutria and other rodents in vast regions of central Europe over the last 15 years. Unfortunately, this caused in many instances considerable damage on large rivers along dykes and earthworks in the floodplain areas, leading to an increased risk of bank failures. However, most of these mammals belong to protected species. This work is aimed at showing positive experience in cooperation with universities, research institutes and environmental agencies regarding measures to permanently safeguard the banks using composite erosion control systems with polymer coated steel wire net (as flexible reinforcement component) and a geosynthetic (to promote vegetation growth). The steel mesh component works as an effective long-term barrier against the intrusion of mammals, discouraging them from digging inside the core of the dyke. An analysis of the sensitive areas to be protected led also to definition of the characteristics of these interventions (length, shape, escape ways, population areas, etc.). The study will present several additional benefits when using polymer steel nets along dykes, such as: high and durable erosion protection in overflow areas, promotion of fast and effective vegetation growth (increasing stability), surface protection against ice impacts (in northern regions), ease of installation, maintenance, ability to conform to irregular shapes of the slope. This work will also present the positive outcome of research studies along dykes in Germany, Austria and in Italy.展开更多
Some novel 1:1 and 1 :2 Fe complex azo dyes were synthesized in this study.The mass spectrum analysis of 1:1 and 1:2 Fe complex azo dyes is presented.Lightfastness,rubbing fastness and washing fastness of these meta...Some novel 1:1 and 1 :2 Fe complex azo dyes were synthesized in this study.The mass spectrum analysis of 1:1 and 1:2 Fe complex azo dyes is presented.Lightfastness,rubbing fastness and washing fastness of these metallized complex dyes were evaluated for use on wool.Results show that these dyes are of good lightfastness and satisfactory brown shades.展开更多
Overabundant and unbalanced input of nutritional elements to soil has a negative effect to the yield and quality of lettuce. Accumulation of nitrates and harmful effects of the chloride ion are the reasons why there i...Overabundant and unbalanced input of nutritional elements to soil has a negative effect to the yield and quality of lettuce. Accumulation of nitrates and harmful effects of the chloride ion are the reasons why there is a need to establish an optimal quantity and relation of nutrients in lettuce nourishment. In the experiment which was carried out during years 2010 and 2011 on the farm of Secondary Agricultural Boarding School in Futog, nitrate content in a fresh mass of lettuce (mg NO3/kg) was obesrved, in dependence on applied compound fertilizers produced by different technologies at different quantities of nitrate and potassium fertilizers. The results of the research show that in a technological ripeness, the highest average lettuce yield has been obtained in the treatment where the highest dosage of nitrate fertilizers was used in spring, in a combination with complex fertilizers in autumn. The lowest average yield has been obtained on the control plot. The highest average nitrate concentration in a fresh lettuce mass has been recorded in using technology of applying mixed fertilizers and the smallest in using a technology of complex fertilizers. At the moment of harvest, the highest nitrogen content in a dry mass of a plant has been recorded when complex fertilizers of phosphorus and potassium were used by the technology of mixed fertilizers.展开更多
Solid oxide fuel cell–proton exchange membrane(SOFC–PEM) hybrid system is being foreseen as a valuable alternative for power generation. As this hybrid system is a conceptual design, many uncertainties involving inp...Solid oxide fuel cell–proton exchange membrane(SOFC–PEM) hybrid system is being foreseen as a valuable alternative for power generation. As this hybrid system is a conceptual design, many uncertainties involving input values should be considered at the early stage of process optimization. We present in this paper a generalized framework of multi-objective optimization under uncertainty for the synthesis/design optimization of the SOFC–PEM hybrid system. The framework is based on geometric, economic and electrochemical models and focuses on evaluating the effect of uncertainty in operating parameters on three conflicting objectives: electricity efficiency, SOFC current density and capital cost of system. The multi-objective optimization provides solutions in the form of a Pareto surface, with a range of possible synthesis/design solutions and a logical procedure for searching the global optimum solution for decision maker. Comparing the stochastic and deterministic Pareto surfaces of different objectives, we conclude that the objectives are considerably influenced by uncertainties because the two trade-off surfaces are different.展开更多
文摘A new cyclometalated iridium(IlI) complex Ir(DPP)3 (DPP=2,3-diphenylpyrazine) was prepared by reaction of DPP with iridium trichloride hydrate under microwave irradiation. The structure of the complex was confirmed by elemental analysis, ^1H NMR, and mass spectroscopy. The UV-Vis absorption and photoluminescent properties of the complex were investigated. The complex shows strong ^1MLCT (singlet metal to ligand charge-transfer) and aMLCT (triplet metal to ligand charge-transfer) absorption at 382 and 504 nm, respectively. The complex also shows strong photoluminescence at 573 nm at room temperature. These results suggest the complex to be a promising phosphorescent material.
基金Projects (50172030, 50972025, 50990303, 51172038) supported by the National Natural Science Foundation of ChinaProject supported by the Liaoning BaiQianWan Talents Program, China+1 种基金Projects (N110802001, N100702001) supported by the Fundamental Research Funds for the Central Universities, ChinaProject supported by the China Scholarship Council
文摘Red-emission (Y0.95Eu0.05)2O3 submicron spheres and microplates were selectively obtained via hydrothermal precursor synthesis (150 °C, 12 h) followed by calcination at 1000 °C. Characterizations of the products were carried out by combined means of XRD, FT-IR, FE-SEM and PL analysis. The precursors could be modulated from basic-carbonate submicron spheres to normal carbonate microplates by increasing the molar ratio of urea to Y+Eu from 10 to 40-100. The resultant oxides largely retain their respective precursor morphologies at 1000 °C, but morphology confined crystal growth was observed for the microplates, yielding more enhanced exposure of the (400) facets. Both the (Y0.95Eu0.05)2O3 spheres and microplates exhibit nearly identical positions of the PL bands and similar asymmetry factors of luminescence [I(5D0→7F2)/I(5D0→7F1), ~11] under 250 nm excitation, but the microplates show a significantly strong red emission at ~613 nm ( ~1.33 times that of the spheres) owing to their larger particle size and denser packing of primary phosphor crystallites.
文摘In recent years, production of engine fuels and energy from biomass has drawn much interest. In this work, we conducted a novel integrated process for the preparation of bio-hydrogen and bio-fuels using lignocellulosic biomass pyrolysis-oil (bio-oil). The process includes (i) the production of bio-hydrogen or bio-syngas by the catalytic cracking of bio-oil, (ii) the adjustment of bio-syngas, and (iii) the production of bio-fuels by ole nic polymerization (OP) together with Fischer-Tropsch synthesis (FTS). Under the optimal conditions, the yield of bio-hydrogen was 120.9 g H2/(kg bio-oil). The yield of hydrocarbon bio-fuels reached 526.1 g/(kg bio-syngas) by the coupling of OP and FTS. The main reaction pathways (or chemical processes) were discussed based on the products observed and the catalyst property.
基金Supported by the Proyecto Fondecyt (1040089,1090098)
文摘While conventional wastewater treatments for urban effluents are fairly routine and have proved highly effective,industrial wastewater requires more complex and specific treatments.This paper provides a technological strategy for removal of recalcitrant contaminants based on a hybrid treatment system.The model effluent containing a binary mixture of synthetic dyes is treated by a combination of a preliminary physicochemical stage followed by a biological stage based on ligninolytic enzymes produced by Phanerochaete chrysosporium.This proposal includes biosorption onto peat as pretreatment,which decreases the volume and concentration to be treated in the biological reactor,thereby obtaining a completely decolorized effluent.The treated wastewater can therefore be reused in the dyeing baths with the consequent saving of water resources.
基金the New Century Excellent Talents in University, MOE, China (No. NCET-04-0526)the Specialized Research Fund for the Doctoral Program of Higher Education, MOE, China (No. J20050398)the Key Project of Wenzhou (No. G2004034), China
文摘Plastic pipes reinforced by cross helically wound steel wires (PSP), which have exhibited excellent mechanical performance, consist of inner polyethylene (PE) layer, winding layer and outer PE layer. The winding layer is composed of two monolayers where steel wires are cross helically wound. An analytical procedure is developed to predict the short-term burst pressure of PSP as the monolayer is assumed to be elastic and orthotropic. The 3D anisotropic elasticity and Maximum Stress Failure Criterion are employed in the formulation of the elasticity problem. Good agreement between the theoretical results and the experimental data shows that the proposed approach can well predict the short-term burst pressure of PSP.
文摘Bipolar plates for proton exchange membrane fuel cell (PEMFC) where polymer is used as binder and graphite is used as electric filler were prepared by means of compression molding technology. Study on the effects of graphite particle size and shape on the bipolar plate performance, such as electrical conductivity, strength, etc. showed that with decrease of graphite particle size, bulk electrical conductivity and thermometric conductivity decreased, but that flexural strength was enhanced. After spherical graphite occurrence in flake-like form, the flexural strength of the bipolar plate was enhanced, electrical conductivity increased but thermal conductivity decreased in direction paralleling pressure direction, and both electrical conductivity and thermometric conductivity reduced in direction perpendicular to pressure direction.
基金Project supported by Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institutions, Ministry of Education, China
文摘A kind of nanokaolin powder with a thickness of 20-50nm and an average diameter of 300nm is produced through combined procedure of purification, delamination, surface modification and pulverization. The application experiments in butadiene rubber (BR), ethylene-propylene diene methylene (EPDM), and natural rubber (NR) indicates that this nano-kaolin powder material is much better than precipitated silica in reinforcement, while in styrene-butadiene rubber (SBR) it is close to precipitated silica. Nanokaolin is of superiority in elasticity, elongation at break, anti-flexure property.
基金Supported by the State Key Laboratory of Dyes and Surfactants Fine Chemicals.
文摘Seven novel fluorescent coumarin derivatives were synthesized from 7-diethylamino-4-chloro-3-formyl-coumarin. The spectra of absorption, excitation and emission were dependent not only on the structures and also on the concentration of dyes. The PPP-MO predictions can only be consistent with the spectra in dilute solutions.
基金The authors are grateful for the financial supports from the National Natural Science Foundation of China(51971251,51774336).
文摘The pore constitution and tortuosity factor of porous TiAl intermetallic were studied on the basis of the variation behavior of pore structure parameters and the discrete particle model. The pore formation mechanism of porous TiAl is mainly ascribed to three aspects: the clearance space in green compact, the diffusive pores in the reaction process and the phase transition pores, resulting in the open porosities of 5.6%, 42.9% and 1.3%, respectively. According to the Hagen-Poiseuille equation, the tortuosity factor of porous TiAl is determined in the range of 1.3-2.2. Based on the discrete particle model and the variation rule of the tortuosity factor, the tortuosity factor depends mainly on the parameters of fabrication constant, particle shape factor, clearance distance and powder particle size. The quantitative relationships among them have been established, which can be used as the basis for adjusting the pore structure of porous intermetallics.
基金Supported by the National Natural Science Foundation of China (No.50172041)partly by the Chinese State Key Labora-tory for Corrosion and Protection.
文摘K2FeO4 powders were synthesized by the ex-situ and in-situ electrochemical methods, respectively, and characterized by infrared spectrum (IR), scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and BET. Their electrochemical performances were investigated by means of galvanostatic discharge and electrochemi-cal impedance spectroscopy (EIS). The results of physical characterization showed that the two samples have simi-lar structural features, but their surface morphologies and oriented growth of the crystals are different, which results in smaller specific surface area and lower solubility of the ex-situ electrosynthesized K2FeO4 sample. The results of discharge experiments indicated that the ex-situ electrosythesized K2FeO4 electrode has much larger discharge ca-pacity and lower electrode polarization than the in-situ electrosynthesized K2FeO4 electrode. It was found from the results of EIS that lower electrochemical polarization might be responsible for the improvement on the discharge performance of the ex-situ electrosynthesized K2FeO4 electrode.
文摘Permacol mesh has shown promise when used in abdominal wall repair,especially in the presence of a contaminated surgical field.This biomaterial,derived from porcine dermis collagen,has proposed advantages over synthetic materials due to increased biocompatibility and reduced foreign body reaction within human tissues.However,we present a case report describing a patient who displayed rejection to a Permacol mesh when used in the repair of abdominal wound dehiscence following an emergency laparotomy.Review of the English language literature using PubMed and Medline, showed only two previously published cases of explantation of Permacoldue to sepsis or wound breakdown. The authors believe this is the first case of severe foreign body reaction leading to rejection of Permacol.Both animal and human studies show conflicting evidence of biocompatibility.There are several reports of successful use of Permacolto repair complex incisional herniae or abdominal walls in the presence of significant contamination.It appears from the literature that Permacolis a promising material,but as we have demonstrated,it has the potential to evoke a foreign body reaction and rejection in certain subjects.
基金Supported by the Czech Scientific Foundation (No.106/03/ H150)
文摘Ccanposites are common material constructions for high-tech use now. Mechanical properties of woven reinforced composites are influenced by voids inside the structure. Voids could be classified to the two sections. Long and thin cracks are more dangerous than pores. It is important to find relations between preparation and place of occurrence of voids. This paper classifies defects according to rise mechanism, point of occurrence, orientation, size and affect to the properties. Image analysis was used for observing samples. Future work would be oriented not only to observing real samples, bet also to calculate mechanical properties frwn real and ideal structures in 3D woven reinforced composites.
基金supported by the National Natural Science Foundation of China(No.21102099)
文摘In this study, a new zirconium-mediated cycloaddition for preparing dibenzosilole derivatives was developed using siliconbridged diynes and electron-withdrawing alkynes as starting materials. The preparation of silicon-bridged diynes from 1-bromide-2-iodobenzene, terminal alkynes, and dimethyldichlorosilane was also studied. Unlike in the previous synthesis methods, much higher yields of electron-withdrawing group-substituted dibenzosilole derivatives were obtained. In addition, a new synthesis strategy for preparing benzonaphthosilole derivatives using internal alkynes, 1,4-dibromobenzene, and electron-withdrawing alkynes as starting materials is proposed. Compared with previous methods, alkyl, phenyl, and electron-withdrawing groups can be successfully introduced onto aromatic rings, and the positions of these substituents can be easily controlled. The cycloaddition reactions for dibenzosilole and benzonaphthosilole derivatives are highly efficient one-pot processes, and the raw materials are available and easily prepared. Using these new methods, a series of novel multisubstituted dibenzonsilole and benzonaphthosilole derivatives were obtained effectively.
基金The author is grateful to the management and staff of Center Research Development laboratory(HZL,Debari),India for their support with this research and permitting to publish the work.
文摘Synthetic dyes are commonly used for graphite depression in poly-metallic flotation circuits; however,these dyes can be very expensive. The aim of this study is to evaluate performance of certain low-cost alternative depressants for a complex lead-zinc(Pb-Zn) ore rich in graphite(Gr-C) on a conventional mini pilot-scale flotation circuit. The reagents used were commercial and industrial grade starch; agro-based waste-sugarcane bagasse and charred(burnt) bagasse powder. The primary evaluation criteria were quality(grades) of lead and zinc concentrates, their recoveries(%), and graphite rejection(%) in the tails.Benchmark tests using nigrosine as graphite depressant showed 94.3% rejection of Gr-C. The results with commercial starch were found as effective with 93.8% graphite rejection. Furthermore, bagasse powder showed potential in improving product quality(36.4% and 65.6% Pb grade and recovery) with an intermediate effectiveness in graphite rejection(85.6%). The order of effectiveness in Gr-C rejection follows nigrosine % commercial starch > bagasse > industrial starch > charred bagasse. In addition, the effect these depressants on silver(byproduct) grade and recovery was also investigated.
文摘Recent studies show an increase in the population of beavers, nutria and other rodents in vast regions of central Europe over the last 15 years. Unfortunately, this caused in many instances considerable damage on large rivers along dykes and earthworks in the floodplain areas, leading to an increased risk of bank failures. However, most of these mammals belong to protected species. This work is aimed at showing positive experience in cooperation with universities, research institutes and environmental agencies regarding measures to permanently safeguard the banks using composite erosion control systems with polymer coated steel wire net (as flexible reinforcement component) and a geosynthetic (to promote vegetation growth). The steel mesh component works as an effective long-term barrier against the intrusion of mammals, discouraging them from digging inside the core of the dyke. An analysis of the sensitive areas to be protected led also to definition of the characteristics of these interventions (length, shape, escape ways, population areas, etc.). The study will present several additional benefits when using polymer steel nets along dykes, such as: high and durable erosion protection in overflow areas, promotion of fast and effective vegetation growth (increasing stability), surface protection against ice impacts (in northern regions), ease of installation, maintenance, ability to conform to irregular shapes of the slope. This work will also present the positive outcome of research studies along dykes in Germany, Austria and in Italy.
文摘Some novel 1:1 and 1 :2 Fe complex azo dyes were synthesized in this study.The mass spectrum analysis of 1:1 and 1:2 Fe complex azo dyes is presented.Lightfastness,rubbing fastness and washing fastness of these metallized complex dyes were evaluated for use on wool.Results show that these dyes are of good lightfastness and satisfactory brown shades.
文摘Overabundant and unbalanced input of nutritional elements to soil has a negative effect to the yield and quality of lettuce. Accumulation of nitrates and harmful effects of the chloride ion are the reasons why there is a need to establish an optimal quantity and relation of nutrients in lettuce nourishment. In the experiment which was carried out during years 2010 and 2011 on the farm of Secondary Agricultural Boarding School in Futog, nitrate content in a fresh mass of lettuce (mg NO3/kg) was obesrved, in dependence on applied compound fertilizers produced by different technologies at different quantities of nitrate and potassium fertilizers. The results of the research show that in a technological ripeness, the highest average lettuce yield has been obtained in the treatment where the highest dosage of nitrate fertilizers was used in spring, in a combination with complex fertilizers in autumn. The lowest average yield has been obtained on the control plot. The highest average nitrate concentration in a fresh lettuce mass has been recorded in using technology of applying mixed fertilizers and the smallest in using a technology of complex fertilizers. At the moment of harvest, the highest nitrogen content in a dry mass of a plant has been recorded when complex fertilizers of phosphorus and potassium were used by the technology of mixed fertilizers.
基金Supported by the National Natural Science Foundation of China(50876117)the Fundamental Research Funds for the Central Universities(CDJXS11141149)
文摘Solid oxide fuel cell–proton exchange membrane(SOFC–PEM) hybrid system is being foreseen as a valuable alternative for power generation. As this hybrid system is a conceptual design, many uncertainties involving input values should be considered at the early stage of process optimization. We present in this paper a generalized framework of multi-objective optimization under uncertainty for the synthesis/design optimization of the SOFC–PEM hybrid system. The framework is based on geometric, economic and electrochemical models and focuses on evaluating the effect of uncertainty in operating parameters on three conflicting objectives: electricity efficiency, SOFC current density and capital cost of system. The multi-objective optimization provides solutions in the form of a Pareto surface, with a range of possible synthesis/design solutions and a logical procedure for searching the global optimum solution for decision maker. Comparing the stochastic and deterministic Pareto surfaces of different objectives, we conclude that the objectives are considerably influenced by uncertainties because the two trade-off surfaces are different.