最新刊期
卷 ， 期 1 ， 2000
- 摘要：The reinforcing action of reinforcing fillers, such as many kinds of silica aerogel on silicone rubber, has been widely studied. However, the reinforcing action of non-reinforcing fillers were less concerned. In this study, several non-reinforcing fillers were used to reinforce the room temperture vulcanizable (RTV) silicone rubber. The effects of filler type, filler particle size and distribution on the tensile strenght, elongation and thermal stability of filled silicone rubber were disscussed. The result indicated that some of non-reinforcement fillers could reinforce RTV silicone rubber effectively,if the filler particle sizes are proper. It is interesting to find a maximum reinforcing action when the filler particle size and filer particle size distribution are optimized. The isothermal degradation indicated that the SiC could improve the thermal stability of silicone rubber effectively.
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发布时间：2021-03-19 - 摘要：Alkali-chitosan method was employed to synthesize cyanoethyl chitosan (CNCS) with different degree of substitution (DS) from chitosan by controlling the reaction time.The effect of DS (from 0.36 to 1.21) on the liquid crystalline behaviors of CNCS was investigated.The change of DS showed no obvious influence on the critical concentration (C*) of liquid crystalline-isotropic transition for CNCS/dichloroacetic acid (DCA) solution,because a small substitution degree is large enough to destroy most of the inter-and-intramolecular hydrogen banding.High molecular weight (Mw) chitosan was depolymerized by nitrous acid to get chitosans of different Mw,proceeded by cyanoethylation using alkali chitosan method to synthesize CNCS of different Mw,Investigation was carried to the determine the effect of Mw on the lyotropic liquid crystalline behaviors of CNCS.The C* of CNCS and their obvious dependence on Mw imply that CNCS is a semi-rigid natural polymer with reatively high chain rigidity.
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发布时间：2021-03-19 - 摘要：Adsorption and desorption behaviours of protein human serum albumin (HSA) on thermosensitive magnetic polymer microspheres were investigated.At higher temperature,microspheres deswelled and susceptible to absorb larger amount of proteins,some of them could be desorbed at lower temperature.The extent of adsorption was found to depend on the pH value,protein concentration and incubation time also.At higher pH value,less of proteins could be absorbed because of the electrostatic repulsive force between the protein and microspheres.Increasing inculbation time or protein concentration was favorable to the adsorption of proteins.
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发布时间：2021-03-19 - 摘要：A series of novel optical active shish-kebab type liquid-crystalline copolymers was synthesized via solution polycondensation of terephthaloyl chloride with 2,5-bis\[4-(S)-2-methyl butoxy) benzoyloxy\] hydroquinone and hexandiol.The copolymers were characterized by GPC、DSC、TG、WAXD、polarizing microscope and rotational analysis instrument.It was found that all the copolymers change to liquid crystal phase when heated to their Tm.The broken focal-conics texture or sanded texture can be observed. Temperature-variable X-ray diffraction realized that they are chiral smetic C(S*C) phase. Both melting temperatures (Tm) and isotropization temperatures (Ti) change regularly with varying the hexandiol content in the copolymers. It was found that the rotation was maintained during the synthesis process and all the chiral copolymers were optically highyl active.
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发布时间：2021-03-19 - 摘要：copolymers containing rare earth metal were prepared by the copolymerization of rare earth complexes with Methyl Methacrylate (MMA).The formula of rare erath complexes can be expressed as:RE(β)2(AA)(L)n ,where RE=Sm,Eu,Tb,Ho or Y,β=acac,BA,DBM or TTA,AA=acrylic acid, L=1,10-phenanthroline(phen),or 2,2′-bipyridyl(bipy), n=0,1 or 2.These rare earth copolymers were characterized by elemental analysis,FT-IR, 1H-NMR,XPS,and UV.They are soluble in common organic solvents,such as benzene,chlolroform,THF and acetone,which make them useful for forming films.Their molecular weights (Mw)are in the range of 20,000～50,000 measured by GPC.Rare earth complex units in copolymers did not dissociate during polymerization and purification.Thermal analysis indicated that copolymers show higher thermal stability than PMMA. The effect of monomer concentration,initiator concentration,solvent,reaction time and temperature on copolymerization were discussed.The kinetic behavior of copolymerization was also investigated.The reactivity ratio of MMA(r1)and Sm(BA)2(AA)(r2)were found to be 1.62 and 0.056,respectively.
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发布时间：2021-03-19 - 摘要：The emulsion polymerization of styrene by Cu0/2,2′-bipyridine (Bpy)/CCl4 and CuCl2/Bpy/azobisisobutyronitrile (AIBN) catalyst/initiator system was studied,respectively.The results show that the molecular mass increased in linear with the conversion of monomer,which hints the emulsion polymerization may be a “living/controlled” system,and the incipient molecular mass,which are as 5 to 20 times as the theory one,may be up to 10,000s once the polymerization was initiated.The polymer MWD from Cu0/Bpy/CCl4 emulsion system accords with that from ist bulk polymerixation.Moreover,the MWD from CuCl2/Bpy/AIBN emulsion system is broader than that from ist bulk polymerization,but the narrowest one in this emulsion system can reach 1.64.Essentially,no difference was found between emulsion and suspension polymerization in "living"character but in kinetics.It was found that the pH-value decreased in the course of polymerization,the descending rate of pHvalue may influence on polymerization rate.
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发布时间：2021-03-19 - 摘要：In order to obtain required polymer materials,acrylic acid was grafted onto powdered isotactic polypropylene by electron beam pre-irradiation technique.All process (including irradiation dose,storage time,reaction temperature and graft-co-polymerization) was carried out in air.The effects of several reaction conditions was investigated and discussed in detailed.The results show that grafting can well be achieved without purging oxygen and the grafted materials show a promising future in ion-adsorption.In this reaction system,suitable storage times play little effect on grafting yield. The Mohr's concentration and temperature are the most important reaction condition ingrafting.The favorable Mohr's concentration is about 0.08%,keep the reaction temperature at 60℃ can achieve the best result.Optional reation condition was generalized for large-scale production of the desired materials.
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发布时间：2021-03-19 - 摘要：A novel water-solube,π conjugated polymer-poly{(pyrrole-2,5-diyl)\[ p-N,N-(dimethylamino) benzylidene\]} (PPDMAB) was synthesised.The chemical structutre and properties of the polymer were characterized by EA,XPS,FT-IR,UV-vis-NIR, in-situ UV-vis-NIR spectroscopy,solubility measurement and conductivity measurement.The conductivity of the polymer increased by 2～4 degrees after protonated,H2SO4-doped and I2doped.Reversible change of color (brown〈=〉dark blue) was observed while protonated and deprotonated.
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发布时间：2021-03-19 - 摘要：Syndiotactic polystyrene (sPS) and polyethylene were comparatively synthesized with homogeneous catalytic systems composing η5-pentamethycyclopentadienyltribenzyloxy titanium [Cp*Ti(OBz)3] and various modified methylaluminoxanes (mMAO).The content of TMA in mMAO can be controlled by regulating H2O/TMA molar ratio during the preparation of mMAO by partial hydrolysis of TMA with Al2(SO4)3·18H2O.The effect of Al/Ti molar ratio on polymerization of styrene as well as ethylene have been studied in detail. The oxidation states of titanium in Cp* Ti(OBz)3/MAO catalytic systems were determined by redox titration method. It seems that active centre of Ti(Ⅲ) is favorable for styrene syndiospecific polymerization with higher catalytic activity,while Ti(Ⅳ)center is favorable for ethylene polymerization.The styene syndiospecific polymerization may also be nifluenced by the external addition of tri-isobutyl-aluminum(TIBA) into the same catalytic sistem giving higer yiela but slightly lower molecuar weight of sPS.
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发布时间：2021-03-19 - 摘要：The samples of chitosan with different degree of deacetylation and the molecular weight range of 1.3～15.1×105 were prepared and characterized by FTIR and viscosity measurements. The phase transition and states of the lyotropic liquid crystals of chitosan in dichloroacetic acid were studied by polarized microscopy. It was shown that the critical concentration for the formation of the liquid crystals decreases slightly as molecular weight of chitosan increases in the range of 105～106. It was found that the effect of the deacetylation degree in the range of 70%～90% on the critical concentration could be neglected.l The experimental values of the critical concentration were in agreement with the calculated ones based on the Khokhlov-Semenov-Odijik theory,which indicated that the lyotropic behavior of chitosan in dichloroacetic acid can be well described with wormlike chain model.
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发布时间：2021-03-19 - 摘要：The influences of temperature, melting time, polyester content and molecular weight on the apparent viscosity for the melt of poly(ether/ester) block copolymers were studied by means of Instron 3211 capillary rheometer. It was shown in experimental results that the melt was a pseudoplastic and non-Newtonian fluid, but the variation of apparent viscosity for the copolymers with the shear rate was not in agreement with the power law model. The apparent viscosity of the poly(ether/ester) melts increased with the content and the molecular weight of the polyether segments.It was shown that the relationship between the zero-shear viscosity obtained according to Spencer-Dillon equation and temperature obeys Andrade equation.The activation energies of viscous flow for the ploy (ether/ester) block copolymers were 39.4,84.2and 169.3kJ/mol,as the contents of polyester segments were 30%,45%and 65%,respectively.
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发布时间：2021-03-19 - 摘要：A simple method of calculating the interfacial tensions was given under the simplified and restricted experimental conditions. Comparing the results of calculation with that of the literature reports, it was proved by calculation that the thermodynamically preferred morphology of the poly(acrylate-styrene) composite latex could be predicted exactly by using the interfacial tensions calculated by the above method. According to the required properties of the material, the morphology of poly(buty acrylate)/poly(styrene-methyl methacrylate)core/shell latex was designed by the principle of minimum interfacial free energy change.The composite latex was prepared by seeded semi-continuous emulsion polymerization. The final eauilibrium core/shell morphology of the well-designed latex was confirmed by transmission electron microscope.
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发布时间：2021-03-19 - 摘要：The complex structure of polymer gels was studied with dynamic Monte Carlo simulation based on the principle of gelation theory in a 2D network with periodic condition. The effect of polymerized monomer's (monomers of polymer) movement on the structure of polymer gels was studied. Simulation results indicated that the threshold concentration of gelation and the fractal dimension of polymer gels could be considerably decreased compared with the kinetic gelation model and the DLA model when polymerized monomere were allowed to move,especially when the total monomer concentration is low. The pore size distribution was acquired by moving bubble method. It was found that the ratio of big pores in our gel network was higher than that based on the Ogston's model.That indicates the simulated gels was of great inhomogeneity.
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发布时间：2021-03-19 - 摘要：Viscosity of partially hydrolyzed polyacrylamide (HPAM)/aluminum citrate (AlCit) colloidal dispersion gel has been measured in gelation of the system. The result showed that the viscosity of HPAM/AlCit cross-linking system increased with reaction time when the concentration of HPAM is higher, and the final viscosity of the system is higher than the viscosity of HPAM solution with same concentration of HPAM. The viscosity of HPAM/AlCit cross-linking system is decreased with reaction time when the concentration of HPAM is lower, and the final viscosity of the system is lower than the viscosityof HPAM solution with same concentration of HPAM. When the concentration of HPAM lower than critical concentration the HPAM/AlCit cross-linking system formed thin colloidal dispersion gel (TCDG).Under the experimental condition,the critical concentration of HPAM is between 150 and 300 mg/L.When the concentration of HPAM is between the critical concentration and 700 mg/L the HPAM/AlCit cross-linking system formed concentrated colloidal dispersion gel (CCDG).When the concentration of HPAM is higher than 700mg/L the HPAM/AlCit cross-linking system formed bulk gel.
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发布时间：2021-03-19 - 摘要：The rheological property of metallocene polyethylene MPE(ethylene and 1-butene copolymer) and conventional LDPE has been studied in detail by using a Rheometrics Scientifics DSR-200 rheometer with parallel plate geometry. Measurements include steady-state viscosity, dynamic viscoelasticity, followed by linear fitted with the modified cross model.MPE has poor processability due to its narrow MWD. Compared with conventional LDPE,MPE has higher apparent viscosity in middle shear rate range,low sensitivity to shearing,and higher values of shear rate and shear stress in the transition region from Newtonian to power-law behavior. In order to improve its processability,MMPE modified from MPE has been produced. MMPE has all the advantages of metallocene polyethylene,and also has good processability:lower apparent viscosity,higher sensitivity to shearing,and lower values of shear rate and shear stress in the transition region from Newtonian to power-law behavior.The blown film with good mechanical properties has been made from MMPE.
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发布时间：2021-03-19 - 摘要：The copolymerization of styrene and ethylene was carried out using a novel catalytic system of η5-pentamethylcyclopentadienyltribenzyloxy titanuim [Cp*Ti(OBz)3] and methylaluminoxane(MAO). The optimum copolymerization conditions,including copolymerization temperature(T), time(t), Al/Ti molar ratio and Cp*Ti(OBz)3 concentration([Ti]) were investigated. The copolymerization products were fractionated by successive solvents extraction with boiling butanone and THF. The copolymers, chiefly existed in THF soluble fractions,were isolated and characterized by 13C-NMR,DSC,WAXD and DMA methods. They are confirmed to be an elastoplastic and amorphous random copolymer [poly(S-co-E)] with a single glass transition temperature (Tg=44.06℃) and a viscoelastic behavior.
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发布时间：2021-03-19 - 摘要：Copolymerization of ethylene with 1 octene is reported based on metallocene, rac-C2H4(Ind)2Hf(NMe2)2 (1) (Ind=η5-indenyl) and (CH3)2C(Fluo)(Cp)ZrMe2 (2) (Cp=η5-cyclopentadienyl,Fluo=η5-fluorienyl).The result shows that the copolymerization rate increases with the increase of comonomer molar ratio ([O]/[E]).Further increase of [O]/[E] reduces copolymerization rate.The activity of 1/Al(iBu)2/[Ph3C][B(C6F5)4](3) is much higher than that of 2/MAO.System 1/Al(iBu)2/[Ph3C][B(C6F5)4](3) is much higher than that of 2/MAO.System 1/Al(iBu)2/3 also shows higher incorporation ability of 1-octene into copolymer than that of 2/MAO.The values of the product rE×rOare below 1for all the resulting copolymer,which correspond to random copolymer structures with a more alternating structure.The melting point(Tm),crystallinity (Xc),intrinsic viscosity ([η]) and density (D) of the type of catalytic system. High comonomer contents of the products show clearly amorphous behavior.All the copolymers show melting within a broad temperature range,duplicate peaks or with shoulder.The copolymers produced by 1/Al(iBu)2H/3 have much higher molecular weight than that of 2/MAO,and have a wider range of density rfom 0.965 to 0.84g/cm3.
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发布时间：2021-03-19 - 摘要：The intercalation and exfoliation behaviour of epoxy resin in an organoclay have been investigated by XRD and DSC methods. It was found that the affinity between the organoclay and epoxy resin was very good and the organoclay was easy to be intercalated by epoxy resin with or without solvent. By direct or solution mixing a stable and homogeneous clay/epoxy intercalated hybrid could be obtained in which the layer spacing of the organoclay was about 3.7nm. At the curing temperature ranging from 80℃ to 160℃ the organoclay was ready to be exfoliated during curing process of the resin and exfoliac\ted nanocomposite could be achieved. It was found that completed exfoliation of the clay could be reached,while the curing degree of the resin was only about 10%.The experiments conducted at 80℃,100℃,120℃ and 150℃ indicated that the time at which complete exfoliation occurred was near to the gelting time of the epoxy resin,meaning that that exfoliation of the clay was dependent on the curing process.
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发布时间：2021-03-19 - 摘要：The toughening mechanism of POM/NBR blends was studied. The results indicate that NBR with high AN content has similar solubility parameter with TPU, and the CN groups or double bond of NBR can capture the formaldehyde or macromolecular free radicals which were produced during POM degradation. This can enhance the compatibility between NBR and POM, thus they can form good alloy. When NBR content reaches 40wt%, the alloy exhibits brittle-ductile transition. The investigation from percolation, rubber-band and quasi-IPN mechanisms indicate that,toughening behavior of NBR to POM and the alloy's B-D transition rule are consistent with POM/TPU system.
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发布时间：2021-03-19 - 摘要：The average chain conformations of polyoxyethylene chain in the third-order interaction approximation and the effect of third-order interaction on persistence vectors are investigated. A priori probabilities of polyoxyethylene chains in the third-order interaction approximation are also calculated,and this method may also be applied to study the average chain conformations of symmetric polymer chain with complex units and of asymmetric polymer chains. The expression of persistence vector in the third-order interaction approximation is also produced.
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发布时间：2021-03-19 - 摘要：The reinforcing and toughening effects of PP blends were studied by the determination of the mechanical properties, dynamic mechanical analysis, DSC, as well as morphology and structures of the cross-sections, which were reinforced by nano-SiO2 rigid particles and toughened by EPDM elastic particles. It was shown that, the above two particles dispersed in PP matrix can increase not only the tougheness but also the strength and the modulus of PP at a great extent. As the blend ratio of PP/nano-SiO2/EPDM is 80/3/20,the two particles have the concerted toughening effect.Nano-SiO2 particles can also increase the crystallization temprature and crystallization rate of PP and decrease its size of spherulite. Nano-SiO2 particles are dispersed in the PP continuous phase in the form of conglomerates which are made up of 6～7 nano-SiO2 particles in average and have a good combination strength with PP matrix. The comprehensive properties of the PP/nano-SiO2/EPDM can match with the engineering plastics.
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发布时间：2021-03-19
Research Article
- 摘要：The composites of rigid rod poly(phenylene terphthalamide) (PPTA) and flexible nylon 6 were prepared by using an in situ polymerization.The anion of PPTA was used as the initiator for the anionic polymerization of caprolactam of form the nylon 6 matrix.SEM photographs showed that PPTA was dispersed in the matrix in a form of microfibril with a diameter of 50～100nm.The microfibril serves as the reinforcing agent in nylon matrix and leads to a nearly two fold increase in modulus,64% increase in tensile strength and a significant reduction in strain to break.The DMTA results also shoued that the mechanical properties of PPTA/nylon 6 composites were greatly inmproved.
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发布时间：2021-03-19 - 摘要：Radical copolymerization of N phenylmaleimide(PHMI) and cyclohexene(CH) was carried out with 2,2-azobisisobutyronitrile(AIBN) in various solvents at 60℃.The copolymer composition was determined by elemental analysis and the results showed that the copolymerization of PHMI with CH in chloroform proceeded in homogeneous system to give an alternating copolymer over a wide range of the comonomer composition in the feed.The presence of the formation of the charge transfer complex(CTC) between PHMI and CH in chloroform was not detected by using UV spectra and 1H-NMR and 13C-NMR spectra and there was cis configuration of CH units in the polymer chains which was determined by analysis for 13C-NMR spectra.In addition, the copolymer of PHMI and CH showed a high glass transition temperature (Tg) and excellent thermal stability, e.g.,the Tg and the initial thermal decomposition temperature (Td)were 200℃ and 350℃,respectively,for the alternating copolymer of PHMI and CH.
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发布时间：2021-03-19 - 摘要：The effect of supercritical fluid on morphology of polystyrene in gas assisted injection molding was studied,the SEM result showed that the morphology of polystyrene treated by supercritical fluid nitrogen gas was very different from that of untreated polystyrene.There was a laminar structure in treated polystyrene that induced by fountain flow when the melt was propelled by the gas in gas assisted injection molding.It was also found that gas penetration induced the occurrence of self-similar structure,e.g.fractal structure which was related with viscosity finger effects.
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发布时间：2021-03-19 - 摘要：An EVAl membrane with polyionic complex (PIC) as a skin layer has been prepared by in situ polyionic complexation between the cationically modified surface of EVAl membrane and the corresponding polyanion solutions.Two types of polyanions like sulfonated EVAl and phosphorylated EVAl,as well as quaternary ammonium modified EVAl membrane were synthesized and used for polyionic complexation.To reach the complete complexation,the amount of polyanion must be well above the cations on the surface of EVAl.The x-ray photoelectron spectron spectroscopy and elemental analysis revealed that the complexation mainly occurred on the surface of EVAl membrane.An asymmetric membrane with more condensed skin layer and porous inner alyer was obtained,which mya find new applications in biologi field.
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发布时间：2021-03-19 - 摘要：Hydrogenation of SBS using RuCl2(PPh3)3 as catalyst and PPh3 as ligand was studied for the first time.Hydrogenated Degree of hydrogenation of SEBS reaches 98%.RuCl2(PPh3)3 which was used as catalyst has high activity and high selectivity (phenyl is not hydrogenated),and gel will not be formed.The band of C C was saturated.So that RuCl2(PPh3)3 has high selectivity.It is shown that the thermal resistance was improved greatly by initial decomposition temperature.Rh-Ru double metal new catalytic system has higher activity than Ru single metal system in hydrogenation of SBS.
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发布时间：2021-03-19 - 摘要：The polymerization of MMA by coordination catalyst of Nd(naph)3-Al(i-Bu)3-α,α’-Dipyridyl was described in this paper.Characterization of the structure of the polymer is revealed by NMR and IR.These studies revealed that the polymer obtained has mainly syndiotactic and shetero structures.Molecular weight and distribution are studied by GPC.Coordinate mechanism was proposed for the MMA polymerization by Nd-Al-α,α’-Dipyridyl.Kinetic studies showed that the MMA polymerization rate is first order with respect to monomer concentration.The apparent activation energy of MMA polymerization reaction is 22.2kJ/mol.
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发布时间：2021-03-19 - 摘要：The photosensitive initiating system composed of 7-diethylamino-3-(2’-N-methylbenzimidazolyl)coumarin dye (DBC) as sensitizer and diphenyliodonium hexafluorophosphate (DIH) as initiator,can be used to initiate the polymerization of methyl methacrylate (MMA) in visible light.When exposed to visible light,coumarin dye/iodonium salt undergoes quick electron transfer from DBC to DIH and free radicals are produced.The visible light photoinduced reaction between DBC and DIH is mainly through the excited singlet state of DBC and thus it is little sensitive to O2.The fluorescence of DBC can be quenched efficiently by DIH and the change is in accord with Stern-Volmer equation and the quench constant Kq can reach 1012M-1S-1.The influence of concentration of DBC on the polymerization rate of MMA shows that counarin free radical act mainly as chain terminator in polymerization and has a stronger tendency to terminate the chain reaction.
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发布时间：2021-03-19
Research Bulletin
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