A new phenylethanoid glycoside, neobudofficide B was isolated from Buddleia officinalis. On the basis of spectral and chemical evidence, the glycoside was identified as β ( 3′, 4′ dihydroxy, 6′ N pyridinechlo...A new phenylethanoid glycoside, neobudofficide B was isolated from Buddleia officinalis. On the basis of spectral and chemical evidence, the glycoside was identified as β ( 3′, 4′ dihydroxy, 6′ N pyridinechloride phenyl ) ethyl O α L rhamnopyranosyl ( 1→3 ) β D ( 4″ O caffeoyl ) glucopyranoside.展开更多
In-situ reactive compatibilization of high-density polyethylene (HDPE)/ground tire rubber (GTR) blends by dicumyl peroxide (DCP) and HY-2045 - a kind of thermoplastic phenolic resin without catalyst was inves...In-situ reactive compatibilization of high-density polyethylene (HDPE)/ground tire rubber (GTR) blends by dicumyl peroxide (DCP) and HY-2045 - a kind of thermoplastic phenolic resin without catalyst was investigated by studying the mor-phology, stress and strain behavior, dynamic mechanical properties and crystallization performance of the blends. Scanning e-lectron microscopy (SEM) results show that there are a lot of fibrous materials distributing in the interface, which connects the dispersed phase with the matrix and obtains better interfacial strength for prominent mechanical properties. The addition of compatibilizers results in the decrease of crystallinity of the blends and the disappearance of an obvious yield phenomenon, which was proved by the differential scanning calorimeter (DSC) test and X-ray diffraction (XRD) characterization Although the crystallinity of the blends decreases,the tensile strength and tensile strain of the blends significantly increases, especially for the HDPE/GTR/DCP/HY-2045 blends, which is possibly attributed to the good compatibility of the blends owing to the in-situ interface crosslinking. In addition, it is found that the compatibilizing HDPE/GTR blends shows a higher tan^ peak temperature and a broaden transition peak for GTR phase.展开更多
Microporous polyolefin hollow fiber membranes were prepared from high density polyethylene (HDPE)-paraffin solution via thermally induced phase separation (TIPS) method. Effects of extraction and cold-drawing cond...Microporous polyolefin hollow fiber membranes were prepared from high density polyethylene (HDPE)-paraffin solution via thermally induced phase separation (TIPS) method. Effects of extraction and cold-drawing condition on membrane structure and performance were investigated.Five volatile solvents were used as extractant. Dimension of hollow fiber and gas permeation rate of membrane were measured. Mierostructure of membrane was examined by Scanning Electronic Microscope (SEM). The results show that the membrane treated by pentane possesses a higher porosity, nitrogen permeability and lower shrinkage than those of membranes extracted by other three extractants. It is also found that the membrane stretched 133% shows the highest porosity and gas permeability in this study.展开更多
Melt blends of low-density polyethylene(LDPE), ethylene vinyl acetate(EVA) and coal with various compositions were prepared through reactive extrusion. The rheological behaviour was studied with respect to the effect ...Melt blends of low-density polyethylene(LDPE), ethylene vinyl acetate(EVA) and coal with various compositions were prepared through reactive extrusion. The rheological behaviour was studied with respect to the effect of blend ratio, shear rate using a rheometer to gain an understanding of processing parameters controlling industrial ap-plication. Compatibility was also evaluated by differential scanning calorimetry(DSC) and scanning electron microscopy(SEM). The results revealed that LDPE/EVA/coal is a partly compatible system showing pseudo-plastic behaviour, increase in viscosity with increased coal content appeares evident only at low shear rate region, viscosity tends to keep consistent approximately but irrelates to coal content at higher shear rate. Blends viscosity and compatibility are attibuted to changes in LDPE crystalline structure and entanglement, together with interaction between macromolecular aliphatic chains in coal and amorphous phase in LDPE and EVA at the boundaries of phases, which comes forth during the rear-rangement process of the crystalline structure.展开更多
The binding energy spectra and electron momentum distributions for the outer valence molecular orbitals of gaseous 2-fluoroethanol have been measured by the non-coplanar asym- metric (e, 2e) spectrometer at impact e...The binding energy spectra and electron momentum distributions for the outer valence molecular orbitals of gaseous 2-fluoroethanol have been measured by the non-coplanar asym- metric (e, 2e) spectrometer at impact energy of 2.5 keV plus binding energy. The quantitative calculations of the ionization energies and the relevant molecular orbitals have been carried out by using the outer-valence Green's function method and the density functional theory with B3LYP hybrid functional. The observed ionization bands in binding energy spectra, as well as the previous photoelectron spectrum which was not assigned, have been assigned for the first time through the comparison between experiment and theory. In general, the the- oretical electron momentum distributions calculated by B3LYP method with aug-cc-pVTZ basis set are in line with the experimental ones when taking into account the Boltzmann- weighted thermo-statistical abundances of five conformers of 2-fluoroethanol.展开更多
AIM: Previous studies suggest that loss of bone mineral density (BMD) frequently occurs in patients with chronic viral liver disease, presenting with histologically proven liver cirrhosis. However, little is known abo...AIM: Previous studies suggest that loss of bone mineral density (BMD) frequently occurs in patients with chronic viral liver disease, presenting with histologically proven liver cirrhosis. However, little is known about the occurrence of bone disease in non-cirrhotic patients with chronic hepatitis B or C. Therefore, it was the aim of this study to evaluate this particular population for BMD and bone turnover markers. METHODS: Biochemical markers of bone turnover and BMD were measured in 43 consecutive patients with HCV (n = 30) or HBV (n = 13) infection without histological evidence for liver cirrhosis. Mean age was 49 years (range 26-77 years). BMD was measured by dual X-ray absorptiometry in the femoral neck (FN) and the lumbar spine (LS) region. In addition, bone metabolism markers were measured. RESULTS: BMD was lowered in 25 (58%) of the patients with chronic hepatitis B or C (FN; 0.76 (0.53-0.99); LS: 0.96 (0.62-1.23) g/cm2). Eight (32%) osteopenic patients were diagnosed with osteoporosis. Bone-specific alkaline phosphatase (P= 0.005) and intact parathyroid hormone (iPTH) (P = 0.001) were significantly elevated in the more advanced stages of fibrosis. Mean T-score value was lower in patients with chronic hepatitis C as compared to patients suffering from chronic hepatitis B; however, the difference was not statistically significant (P= 0.09). CONCLUSION: There was a significantly reduced BMD in non-cirrhotic patients with chronic hepatitis B or C infection. Alterations of bone metabolism already occurred in advanced liver fibrosis without cirrhosis. According to our results, these secondary effects of chronic viral hepatitis should be further investigated.展开更多
Using novel catalyst the pyrolysis of mixed plastics has been considered as an effective way to convert waste plastics into environmental friendly and industrially useful hydrocarbon gas and liquid products. Catalytic...Using novel catalyst the pyrolysis of mixed plastics has been considered as an effective way to convert waste plastics into environmental friendly and industrially useful hydrocarbon gas and liquid products. Catalytic cracking is a promising alternative for plastic wastes recycling. More than 99% of a polymer mixed converted into combustible hydrocarbon in a catalytic converting reaction. The products are mainly middle distillates. In this work equally weighted mixed HDPE (high density polyethylene), LDPE (low density polyethylene) and Polypropylene were degraded. The reaction occurred in a semi batch reactor at several temperatures and catalyst/polymer ratios in search for an optimum operating condition. The products are liquid and gaseous hydrocarbons with minor of residue. The liquid and gas products were in the range of middle distillate cuts of gasoline, kerosene and gas oil. Finally, with a metallic base, yielded 99.5% of given mixed to valuable middle distillate products that include 86% liquid hydrocarbon and 13.5% gas, ranging between C1 and C5 with less percent of residue. The optimum condition for this yield reports at a temperature of 450 ℃ and 10% of catalyst w/w at atmosphere pressure.展开更多
Objective: To introduce the clinical effect among patients who received an unwrapped orbital implant with high density porous polyethylene material (Medpor) after enucleation or evisceration. Methods: Retrospective an...Objective: To introduce the clinical effect among patients who received an unwrapped orbital implant with high density porous polyethylene material (Medpor) after enucleation or evisceration. Methods: Retrospective analysis of a series of 302 patients with anophthalmia who underwent placement of an unwrapped high density porous polyethylene orbital implant. We compared the patients (n=180) who accepted primary implant placement with those (n=122) who accepted secondary implant placement. Parameters evaluated included: age at time of surgery, date of surgery, sex, implant type and size, surgery type, the surgical procedure and technique performed, and complications. Results: The time of follow-up ranged from 2.0 to 58.0 months (mean 32.5 months). A total of 5 of 302 (1.66%) cases had documented postoperative complications. The following problems were noted after surgery: implant exposure, 3 patients (0.99%); implant removed due to orbital infection, 1 patient (0.34%); ptosis, 1 patient (0.34%). There were no significant complications observed in other 297 cases and all implants showed good orbital mo- tility. The clinical effect of primary implant placement is better than that of secondary placement. Conclusion: High density porous polyethylene material can be used successfully as an unwrapped orbital implant in anopthalmic socket surgery with minimal complications. The material is well tolerated, nonantigenic and has low rate of infection and migration.展开更多
The numerical simulation of extrudate swell is significant in extrusion processing.Precise prediction of extrudate swell is propitious to the control of melt flow and the quality of final products.A mathematical model...The numerical simulation of extrudate swell is significant in extrusion processing.Precise prediction of extrudate swell is propitious to the control of melt flow and the quality of final products.A mathematical model of three-dimensional(3D)viscoelastic flow through elliptical ring die for polymer extrusion was investigated.The penalty function formulation of viscoelastic incompressible fluid was introduced to the finite element model to analyze 3D extrusion problem.The discrete elastic viscous split stress(DEVSS)and streamline-upwind PetrovGalerkin(SUPG)technology were used to obtain stable simulation results.Free surface was updated by updating the streamlines which needs less memory space.According to numerical simulation results,the effect of zero-shear viscosity and elongation parameter on extrudate swell was slight,but with the increase of volumetric flow rate and relax time the extrudate swell ratio increased markedly.Finally,the numerical simulation of extrudate swell flow for low-density polyethylene(LDPE)melts was investigated and the results agreed well with others’work.These conclusions provided quantitative basis for the forecasting extrudate swell ratio and the controlling of extrusion productivity shape.展开更多
To explore the problems of dynamic change in production demand and operating contradiction in production process, a new extension theory-based production operation method is proposed. The core is the demand requisitio...To explore the problems of dynamic change in production demand and operating contradiction in production process, a new extension theory-based production operation method is proposed. The core is the demand requisition, contradiction resolution and operation classification. For the demand requisition, the deep and comprehensive demand elements are collected by the conjugating analysis. For the contradiction resolution, the conflict between the demand and operating elements are solved by the extension reasoning, extension transformation and consistency judgment. For the operating classification, the operating importance among the operating elements is calculated by the extension clustering so as to guide the production operation and ensure the production safety. Through the actual application in the cascade reaction process of high-density polyethylene (HDPE) of a chemical plant, cases study and comparison show that the proposed extension theory-based production operation method is significantly better than the traditional experience-based operation method in actual production process, which exploits a new way to the research on the production operating methods for industrial process.展开更多
The purpose of this work was to report excess molar volumes and dynamic viscosities of the binary mixture of diethyl carbonate (DEC)+ethanol. Densities and viscosities of the binary mixture of DEC+ethanol at tempera...The purpose of this work was to report excess molar volumes and dynamic viscosities of the binary mixture of diethyl carbonate (DEC)+ethanol. Densities and viscosities of the binary mixture of DEC+ethanol at temperatures 293.15 K—343.15 K and atmospheric pressure were determined over the entire composition range. Densities of the binary mixture of DEC+ethanol were measured by using a vibrating U-shaped sample tube densimeter. Viscosities were determined by using Ubbelohde suspended-level viscometer. Densities are accurate to 1.0×10-5 g·cm-3, and viscosities are reproducible within ±0.003 mPa·s. From these data, excess molar volumes and deviations in viscosity were calculated. Positive excess molar volumes and negative deviations in viscosity for DEC+ethanol system are due to the strong specific interactions.All excess molar vo-(lumes) and deviations in viscosity fit to the Redlich-Kister polynomial equation.The fitting parameters were presented,and the average deviations and standard deviations were also calculated.The errors of correlation are very small.It proves that it is valuable for estimating densities and viscosities of the binary mixture by the correlated equation.展开更多
Machining is a mechanical process where excess material from a work is removed to produce a product. At the moment different ferrous, non-ferrous materials and industrial blue wax have been used for prototype models. ...Machining is a mechanical process where excess material from a work is removed to produce a product. At the moment different ferrous, non-ferrous materials and industrial blue wax have been used for prototype models. However such materials is very expensive. Hence an attempt is made to substitute these materials by the palm oil based bio-wax produced in Malaysia. In this research, the authors will analyze and investigate whether there is a possibility to use the palm oil based bio-wax material to substitute with the petroleum based industrial-wax. Experimental analyses are carried out to investigate the capability and the strength of the palm oil based bio-wax material. The matrix blends were prepared of fatty acids from oleo-chemicals, palm oil wax, natural ash fibre and low linear density polyethylene (LLDPE) by stirring and melt-mixing. Sample b!ends are machined with lathe machining process. The sample blends showed there was no built edge formation and good smooth surface production.展开更多
We report a method to produce a uniform mixture of uranium dioxide spherical particles in a tungsten matrix. This method involves mixing 0.5 weight percent of high density polyethylene binder with 60 volume percent ur...We report a method to produce a uniform mixture of uranium dioxide spherical particles in a tungsten matrix. This method involves mixing 0.5 weight percent of high density polyethylene binder with 60 volume percent uranium dioxide spheres and 40 volume percent tungsten powders. Initially, hafnium oxide spheres were used as a surrogate for uranium dioxide spheres. The HfO2/W/PE powders were thoroughly mixed in a Turbula, then mixed on a hot plate above the drop point of the binder. These powders were then densified using spark plasma sintering. Microstructure was evaluated using scanning electron microscopy, density was measured and hardness measurements were made. Initial carbon content of the powders were measured and carbon content of the sintered materials was measured. Subsequently, W/UO2/Binder powders were mixed using the same methodology to ensure the process could be used for this system. These powders were sintered using hot isostatic pressing and microstructures evaluated. The resultant microstructures contained uniform distribution of HfO2 and UO2 particles in the tungsten matrix with very low carbon content.展开更多
The activation of HCl by cationic Au in the presence of C2H2 is important for the construction of active Au sites and in acetylene hydrochlorination.Here,we report a strategy for activating HCl by the Au-based support...The activation of HCl by cationic Au in the presence of C2H2 is important for the construction of active Au sites and in acetylene hydrochlorination.Here,we report a strategy for activating HCl by the Au-based supported ionic liquid phase(Au–SILP)technology with the[N(CN)2^–]anion.This strategy enables HCl to accept electrons from[N(CN)2^–]anions in Au–[N(CN)2^–]complexes rather than from pure[Bmim][N(CN)2],leading to notable improvement in both the reaction path and the stability of the catalyst without changing the reaction triggered by acetylene adsorption.Furthermore,the induction period of the Au–SILP catalyst was shown to be absent in the reaction process due to the high Au(III)content in the Au(Ⅲ)/Au(Ⅰ)site and the high substrate diffusion rate in the ionic liquid layer.This work provides a facile method to improve the stability of Au-based catalysts for acetylene hydrochlorination.展开更多
(E) -4-chloro-4' -ethoxystilbene (2a) and (E) -4, 4' - dichlorostilbene (2b) were synthesized by the Witting-Homer reaction. The crystals of 2a and 2b were prepared through solvent evaporation and characteri...(E) -4-chloro-4' -ethoxystilbene (2a) and (E) -4, 4' - dichlorostilbene (2b) were synthesized by the Witting-Homer reaction. The crystals of 2a and 2b were prepared through solvent evaporation and characterized by the single-crystal X- ray diffraction. Molecular structure analysis confirms the E- configuration of C=C bond. The crystal of 2a reveals an orthorhombic and space group Pna21 structure while 2b shows a monoclinic and space group P21/c structure. The electronic structures of 2a and 2b were optimized at B3LYP/6-311 + + G (d, p) level. The Hirshfeld surface and fingerprint plot indicate close O-H and C1-H contacts and π-π stacking in 2a and 2b. Molecular electrostatic potential shows that the O and C1 atoms of 2a and C1 atoms of 2b have the minimum energies and they are more likely to be attacked by electrophiles in reaction. Frontier molecular orbitals analysis demonstrates that the △ELuMO_HOMO of 2a and 2b are 3.85 and 3.91 eV, respectively.展开更多
Metal hydroxides (MAH) consisting of magnesium hydroxide and aluminum hydroxide with a mass ratio of 1:2 were surface-modified by y-diethoxyphosphorous ester propyldiethoxymethylsilane, boric acid and diphenylsilan...Metal hydroxides (MAH) consisting of magnesium hydroxide and aluminum hydroxide with a mass ratio of 1:2 were surface-modified by y-diethoxyphosphorous ester propyldiethoxymethylsilane, boric acid and diphenylsilanediol in xylene under dibutyl tin dilaurate catalyst at 140 ℃. Phosphorus, silicon and boron elements covalently bonded to metal hydroxide particles were detected by X-ray photoelectron spectroscopy. The degradation behavior of the surface-modified MAH was characterized by thermogravimetric analysis. The results show that linear low density polyethylene (LLDPE) composite, filled with 50% (mass fraction) of MAH modified by 5.0% (mass fraction) of modifiers, passes the V-0 rating of UL-94 test and shows the limited oxygen index of 34%, and its heat release rate and average effective heat combustion in a cone calorimeter measurement decrease obviously; The mechanical properties of MAH can be improved by surface-modification. The uniform dispersion of particles and strong interfacial bonding between particles and matrix are obtained.展开更多
In this study, titania nanotubes (TNTs) were prepared by hydrothermal method with the aim to compare the properties of these one-dimensional tubular nanostructures' reinforced nanocomposites with the carbon and hal...In this study, titania nanotubes (TNTs) were prepared by hydrothermal method with the aim to compare the properties of these one-dimensional tubular nanostructures' reinforced nanocomposites with the carbon and halloysite nanotubes' (CNTs and HNTs, respectively) reinforced nanocomposites. Low density polyethylene (LDPE) was used as the matrix material. The prepared nanocomposites were characterized and compared by means of their morphological, mechanical and thermal properties. SEM results showed enhanced interracial interaction and better dispersion of TNTs and HNTs into LDPE with the incorporation of a MAPE compatibilizer, however, these interactions seem to be absent between CNTs and LDPE, and the CNTs remained agglomerated. Contact angle measurements revealed that CNT filled nanocomposites are more hydrophilic than HNT composites, and less than TNT composites. CNTs provided better tensile strength and Young's modulus than HNT and TNT nanocomposites, a 42% increase in tensile strength and Young's modulus is achieved compared to LDPE. Tear strength improvement was noticed in the TNT composites with a value of 35.4 N. mm -1, compared to CNT composites with a value of 25.5 N.mm 1 -s- 1. All the prepared nanocomposites are more thermally stable than neat LDPE and the best improvement in thermal stability was observed for CNT reinforced nanocomposites. CNTs depicted the best improvement in tensile and thermal properties and the MAPE compatibilizer effective- ness regarding morphological, mechanical and thermal properties was only observed for TNT and HNT systems.展开更多
The article deals with potential use of waste materials in construction industry, specifically use of high density polyethylene (HDPE). The article is focused in particular on recycled polyethylene application in pr...The article deals with potential use of waste materials in construction industry, specifically use of high density polyethylene (HDPE). The article is focused in particular on recycled polyethylene application in products designed for construction industry, especially for passive houses. Currently certain building details of passive houses are not perfect or their solution results in higher economic demands related to house purchase and its further use. For the purpose of this thesis details of windows installation in external walls and elimination of thermal bridges in wall footing have been chosen. Products were subject to mathematic modelling of thermal technique and statics. The executed mathematic models documented that products are fully functional and that the suggested product successfully eliminate insufficiencies of some currently applied solutions.展开更多
文摘A new phenylethanoid glycoside, neobudofficide B was isolated from Buddleia officinalis. On the basis of spectral and chemical evidence, the glycoside was identified as β ( 3′, 4′ dihydroxy, 6′ N pyridinechloride phenyl ) ethyl O α L rhamnopyranosyl ( 1→3 ) β D ( 4″ O caffeoyl ) glucopyranoside.
文摘In-situ reactive compatibilization of high-density polyethylene (HDPE)/ground tire rubber (GTR) blends by dicumyl peroxide (DCP) and HY-2045 - a kind of thermoplastic phenolic resin without catalyst was investigated by studying the mor-phology, stress and strain behavior, dynamic mechanical properties and crystallization performance of the blends. Scanning e-lectron microscopy (SEM) results show that there are a lot of fibrous materials distributing in the interface, which connects the dispersed phase with the matrix and obtains better interfacial strength for prominent mechanical properties. The addition of compatibilizers results in the decrease of crystallinity of the blends and the disappearance of an obvious yield phenomenon, which was proved by the differential scanning calorimeter (DSC) test and X-ray diffraction (XRD) characterization Although the crystallinity of the blends decreases,the tensile strength and tensile strain of the blends significantly increases, especially for the HDPE/GTR/DCP/HY-2045 blends, which is possibly attributed to the good compatibility of the blends owing to the in-situ interface crosslinking. In addition, it is found that the compatibilizing HDPE/GTR blends shows a higher tan^ peak temperature and a broaden transition peak for GTR phase.
基金Supported by Zhejiang Natural Science Foundation (ZJNSF Y404096) and SRF for ROCS ,SEM
文摘Microporous polyolefin hollow fiber membranes were prepared from high density polyethylene (HDPE)-paraffin solution via thermally induced phase separation (TIPS) method. Effects of extraction and cold-drawing condition on membrane structure and performance were investigated.Five volatile solvents were used as extractant. Dimension of hollow fiber and gas permeation rate of membrane were measured. Mierostructure of membrane was examined by Scanning Electronic Microscope (SEM). The results show that the membrane treated by pentane possesses a higher porosity, nitrogen permeability and lower shrinkage than those of membranes extracted by other three extractants. It is also found that the membrane stretched 133% shows the highest porosity and gas permeability in this study.
基金Supported by the National Nature Science Foundation(20276056)
文摘Melt blends of low-density polyethylene(LDPE), ethylene vinyl acetate(EVA) and coal with various compositions were prepared through reactive extrusion. The rheological behaviour was studied with respect to the effect of blend ratio, shear rate using a rheometer to gain an understanding of processing parameters controlling industrial ap-plication. Compatibility was also evaluated by differential scanning calorimetry(DSC) and scanning electron microscopy(SEM). The results revealed that LDPE/EVA/coal is a partly compatible system showing pseudo-plastic behaviour, increase in viscosity with increased coal content appeares evident only at low shear rate region, viscosity tends to keep consistent approximately but irrelates to coal content at higher shear rate. Blends viscosity and compatibility are attibuted to changes in LDPE crystalline structure and entanglement, together with interaction between macromolecular aliphatic chains in coal and amorphous phase in LDPE and EVA at the boundaries of phases, which comes forth during the rear-rangement process of the crystalline structure.
基金This work was supported by the National Basic Research Program of China (No.2010CB923301) and the National Natural Science Foundation of China (No.11327404, No.20973160, No.10904136). The au- thors also gratefully acknowledge Professor C. E. Brion from the University of British Columbia (UBC) in Canada for giving us the HEMS programs.
文摘The binding energy spectra and electron momentum distributions for the outer valence molecular orbitals of gaseous 2-fluoroethanol have been measured by the non-coplanar asym- metric (e, 2e) spectrometer at impact energy of 2.5 keV plus binding energy. The quantitative calculations of the ionization energies and the relevant molecular orbitals have been carried out by using the outer-valence Green's function method and the density functional theory with B3LYP hybrid functional. The observed ionization bands in binding energy spectra, as well as the previous photoelectron spectrum which was not assigned, have been assigned for the first time through the comparison between experiment and theory. In general, the the- oretical electron momentum distributions calculated by B3LYP method with aug-cc-pVTZ basis set are in line with the experimental ones when taking into account the Boltzmann- weighted thermo-statistical abundances of five conformers of 2-fluoroethanol.
文摘AIM: Previous studies suggest that loss of bone mineral density (BMD) frequently occurs in patients with chronic viral liver disease, presenting with histologically proven liver cirrhosis. However, little is known about the occurrence of bone disease in non-cirrhotic patients with chronic hepatitis B or C. Therefore, it was the aim of this study to evaluate this particular population for BMD and bone turnover markers. METHODS: Biochemical markers of bone turnover and BMD were measured in 43 consecutive patients with HCV (n = 30) or HBV (n = 13) infection without histological evidence for liver cirrhosis. Mean age was 49 years (range 26-77 years). BMD was measured by dual X-ray absorptiometry in the femoral neck (FN) and the lumbar spine (LS) region. In addition, bone metabolism markers were measured. RESULTS: BMD was lowered in 25 (58%) of the patients with chronic hepatitis B or C (FN; 0.76 (0.53-0.99); LS: 0.96 (0.62-1.23) g/cm2). Eight (32%) osteopenic patients were diagnosed with osteoporosis. Bone-specific alkaline phosphatase (P= 0.005) and intact parathyroid hormone (iPTH) (P = 0.001) were significantly elevated in the more advanced stages of fibrosis. Mean T-score value was lower in patients with chronic hepatitis C as compared to patients suffering from chronic hepatitis B; however, the difference was not statistically significant (P= 0.09). CONCLUSION: There was a significantly reduced BMD in non-cirrhotic patients with chronic hepatitis B or C infection. Alterations of bone metabolism already occurred in advanced liver fibrosis without cirrhosis. According to our results, these secondary effects of chronic viral hepatitis should be further investigated.
文摘Using novel catalyst the pyrolysis of mixed plastics has been considered as an effective way to convert waste plastics into environmental friendly and industrially useful hydrocarbon gas and liquid products. Catalytic cracking is a promising alternative for plastic wastes recycling. More than 99% of a polymer mixed converted into combustible hydrocarbon in a catalytic converting reaction. The products are mainly middle distillates. In this work equally weighted mixed HDPE (high density polyethylene), LDPE (low density polyethylene) and Polypropylene were degraded. The reaction occurred in a semi batch reactor at several temperatures and catalyst/polymer ratios in search for an optimum operating condition. The products are liquid and gaseous hydrocarbons with minor of residue. The liquid and gas products were in the range of middle distillate cuts of gasoline, kerosene and gas oil. Finally, with a metallic base, yielded 99.5% of given mixed to valuable middle distillate products that include 86% liquid hydrocarbon and 13.5% gas, ranging between C1 and C5 with less percent of residue. The optimum condition for this yield reports at a temperature of 450 ℃ and 10% of catalyst w/w at atmosphere pressure.
文摘Objective: To introduce the clinical effect among patients who received an unwrapped orbital implant with high density porous polyethylene material (Medpor) after enucleation or evisceration. Methods: Retrospective analysis of a series of 302 patients with anophthalmia who underwent placement of an unwrapped high density porous polyethylene orbital implant. We compared the patients (n=180) who accepted primary implant placement with those (n=122) who accepted secondary implant placement. Parameters evaluated included: age at time of surgery, date of surgery, sex, implant type and size, surgery type, the surgical procedure and technique performed, and complications. Results: The time of follow-up ranged from 2.0 to 58.0 months (mean 32.5 months). A total of 5 of 302 (1.66%) cases had documented postoperative complications. The following problems were noted after surgery: implant exposure, 3 patients (0.99%); implant removed due to orbital infection, 1 patient (0.34%); ptosis, 1 patient (0.34%). There were no significant complications observed in other 297 cases and all implants showed good orbital mo- tility. The clinical effect of primary implant placement is better than that of secondary placement. Conclusion: High density porous polyethylene material can be used successfully as an unwrapped orbital implant in anopthalmic socket surgery with minimal complications. The material is well tolerated, nonantigenic and has low rate of infection and migration.
基金Supported by the National Science Foundation for Distinguished Young Scholars of China(50425517) the Shandong Province Natural Science Foundation(Y2007F59)
文摘The numerical simulation of extrudate swell is significant in extrusion processing.Precise prediction of extrudate swell is propitious to the control of melt flow and the quality of final products.A mathematical model of three-dimensional(3D)viscoelastic flow through elliptical ring die for polymer extrusion was investigated.The penalty function formulation of viscoelastic incompressible fluid was introduced to the finite element model to analyze 3D extrusion problem.The discrete elastic viscous split stress(DEVSS)and streamline-upwind PetrovGalerkin(SUPG)technology were used to obtain stable simulation results.Free surface was updated by updating the streamlines which needs less memory space.According to numerical simulation results,the effect of zero-shear viscosity and elongation parameter on extrudate swell was slight,but with the increase of volumetric flow rate and relax time the extrudate swell ratio increased markedly.Finally,the numerical simulation of extrudate swell flow for low-density polyethylene(LDPE)melts was investigated and the results agreed well with others’work.These conclusions provided quantitative basis for the forecasting extrudate swell ratio and the controlling of extrusion productivity shape.
基金Supported by the National Natural Science Foundation of China(61104131)the Fundamental Research Funds for Central Universities(ZY1111)
文摘To explore the problems of dynamic change in production demand and operating contradiction in production process, a new extension theory-based production operation method is proposed. The core is the demand requisition, contradiction resolution and operation classification. For the demand requisition, the deep and comprehensive demand elements are collected by the conjugating analysis. For the contradiction resolution, the conflict between the demand and operating elements are solved by the extension reasoning, extension transformation and consistency judgment. For the operating classification, the operating importance among the operating elements is calculated by the extension clustering so as to guide the production operation and ensure the production safety. Through the actual application in the cascade reaction process of high-density polyethylene (HDPE) of a chemical plant, cases study and comparison show that the proposed extension theory-based production operation method is significantly better than the traditional experience-based operation method in actual production process, which exploits a new way to the research on the production operating methods for industrial process.
文摘The purpose of this work was to report excess molar volumes and dynamic viscosities of the binary mixture of diethyl carbonate (DEC)+ethanol. Densities and viscosities of the binary mixture of DEC+ethanol at temperatures 293.15 K—343.15 K and atmospheric pressure were determined over the entire composition range. Densities of the binary mixture of DEC+ethanol were measured by using a vibrating U-shaped sample tube densimeter. Viscosities were determined by using Ubbelohde suspended-level viscometer. Densities are accurate to 1.0×10-5 g·cm-3, and viscosities are reproducible within ±0.003 mPa·s. From these data, excess molar volumes and deviations in viscosity were calculated. Positive excess molar volumes and negative deviations in viscosity for DEC+ethanol system are due to the strong specific interactions.All excess molar vo-(lumes) and deviations in viscosity fit to the Redlich-Kister polynomial equation.The fitting parameters were presented,and the average deviations and standard deviations were also calculated.The errors of correlation are very small.It proves that it is valuable for estimating densities and viscosities of the binary mixture by the correlated equation.
文摘Machining is a mechanical process where excess material from a work is removed to produce a product. At the moment different ferrous, non-ferrous materials and industrial blue wax have been used for prototype models. However such materials is very expensive. Hence an attempt is made to substitute these materials by the palm oil based bio-wax produced in Malaysia. In this research, the authors will analyze and investigate whether there is a possibility to use the palm oil based bio-wax material to substitute with the petroleum based industrial-wax. Experimental analyses are carried out to investigate the capability and the strength of the palm oil based bio-wax material. The matrix blends were prepared of fatty acids from oleo-chemicals, palm oil wax, natural ash fibre and low linear density polyethylene (LLDPE) by stirring and melt-mixing. Sample b!ends are machined with lathe machining process. The sample blends showed there was no built edge formation and good smooth surface production.
文摘We report a method to produce a uniform mixture of uranium dioxide spherical particles in a tungsten matrix. This method involves mixing 0.5 weight percent of high density polyethylene binder with 60 volume percent uranium dioxide spheres and 40 volume percent tungsten powders. Initially, hafnium oxide spheres were used as a surrogate for uranium dioxide spheres. The HfO2/W/PE powders were thoroughly mixed in a Turbula, then mixed on a hot plate above the drop point of the binder. These powders were then densified using spark plasma sintering. Microstructure was evaluated using scanning electron microscopy, density was measured and hardness measurements were made. Initial carbon content of the powders were measured and carbon content of the sintered materials was measured. Subsequently, W/UO2/Binder powders were mixed using the same methodology to ensure the process could be used for this system. These powders were sintered using hot isostatic pressing and microstructures evaluated. The resultant microstructures contained uniform distribution of HfO2 and UO2 particles in the tungsten matrix with very low carbon content.
文摘The activation of HCl by cationic Au in the presence of C2H2 is important for the construction of active Au sites and in acetylene hydrochlorination.Here,we report a strategy for activating HCl by the Au-based supported ionic liquid phase(Au–SILP)technology with the[N(CN)2^–]anion.This strategy enables HCl to accept electrons from[N(CN)2^–]anions in Au–[N(CN)2^–]complexes rather than from pure[Bmim][N(CN)2],leading to notable improvement in both the reaction path and the stability of the catalyst without changing the reaction triggered by acetylene adsorption.Furthermore,the induction period of the Au–SILP catalyst was shown to be absent in the reaction process due to the high Au(III)content in the Au(Ⅲ)/Au(Ⅰ)site and the high substrate diffusion rate in the ionic liquid layer.This work provides a facile method to improve the stability of Au-based catalysts for acetylene hydrochlorination.
文摘(E) -4-chloro-4' -ethoxystilbene (2a) and (E) -4, 4' - dichlorostilbene (2b) were synthesized by the Witting-Homer reaction. The crystals of 2a and 2b were prepared through solvent evaporation and characterized by the single-crystal X- ray diffraction. Molecular structure analysis confirms the E- configuration of C=C bond. The crystal of 2a reveals an orthorhombic and space group Pna21 structure while 2b shows a monoclinic and space group P21/c structure. The electronic structures of 2a and 2b were optimized at B3LYP/6-311 + + G (d, p) level. The Hirshfeld surface and fingerprint plot indicate close O-H and C1-H contacts and π-π stacking in 2a and 2b. Molecular electrostatic potential shows that the O and C1 atoms of 2a and C1 atoms of 2b have the minimum energies and they are more likely to be attacked by electrophiles in reaction. Frontier molecular orbitals analysis demonstrates that the △ELuMO_HOMO of 2a and 2b are 3.85 and 3.91 eV, respectively.
基金Project(20574020) supported by the National Natural Science Foundation of ChinaProject(20061001) supported by the Opening Project of the Key Laboratory of Polymer Processing Engineering, Ministry of Education, ChinaProject (20060106-2) supported by Guangdong Key Projects
文摘Metal hydroxides (MAH) consisting of magnesium hydroxide and aluminum hydroxide with a mass ratio of 1:2 were surface-modified by y-diethoxyphosphorous ester propyldiethoxymethylsilane, boric acid and diphenylsilanediol in xylene under dibutyl tin dilaurate catalyst at 140 ℃. Phosphorus, silicon and boron elements covalently bonded to metal hydroxide particles were detected by X-ray photoelectron spectroscopy. The degradation behavior of the surface-modified MAH was characterized by thermogravimetric analysis. The results show that linear low density polyethylene (LLDPE) composite, filled with 50% (mass fraction) of MAH modified by 5.0% (mass fraction) of modifiers, passes the V-0 rating of UL-94 test and shows the limited oxygen index of 34%, and its heat release rate and average effective heat combustion in a cone calorimeter measurement decrease obviously; The mechanical properties of MAH can be improved by surface-modification. The uniform dispersion of particles and strong interfacial bonding between particles and matrix are obtained.
基金NPRP grant#(NPRP5-039-2-014)from the Qatar National Research Fund(a member of Qatar Foundation)
文摘In this study, titania nanotubes (TNTs) were prepared by hydrothermal method with the aim to compare the properties of these one-dimensional tubular nanostructures' reinforced nanocomposites with the carbon and halloysite nanotubes' (CNTs and HNTs, respectively) reinforced nanocomposites. Low density polyethylene (LDPE) was used as the matrix material. The prepared nanocomposites were characterized and compared by means of their morphological, mechanical and thermal properties. SEM results showed enhanced interracial interaction and better dispersion of TNTs and HNTs into LDPE with the incorporation of a MAPE compatibilizer, however, these interactions seem to be absent between CNTs and LDPE, and the CNTs remained agglomerated. Contact angle measurements revealed that CNT filled nanocomposites are more hydrophilic than HNT composites, and less than TNT composites. CNTs provided better tensile strength and Young's modulus than HNT and TNT nanocomposites, a 42% increase in tensile strength and Young's modulus is achieved compared to LDPE. Tear strength improvement was noticed in the TNT composites with a value of 35.4 N. mm -1, compared to CNT composites with a value of 25.5 N.mm 1 -s- 1. All the prepared nanocomposites are more thermally stable than neat LDPE and the best improvement in thermal stability was observed for CNT reinforced nanocomposites. CNTs depicted the best improvement in tensile and thermal properties and the MAPE compatibilizer effective- ness regarding morphological, mechanical and thermal properties was only observed for TNT and HNT systems.
文摘The article deals with potential use of waste materials in construction industry, specifically use of high density polyethylene (HDPE). The article is focused in particular on recycled polyethylene application in products designed for construction industry, especially for passive houses. Currently certain building details of passive houses are not perfect or their solution results in higher economic demands related to house purchase and its further use. For the purpose of this thesis details of windows installation in external walls and elimination of thermal bridges in wall footing have been chosen. Products were subject to mathematic modelling of thermal technique and statics. The executed mathematic models documented that products are fully functional and that the suggested product successfully eliminate insufficiencies of some currently applied solutions.