When lead tungstate scintillating crystals are used as dense and fast radiat ors for γ ray detectors in high radiation environment in future high energy a c celerators such as LHC,the main problems are (1) radiation ...When lead tungstate scintillating crystals are used as dense and fast radiat ors for γ ray detectors in high radiation environment in future high energy a c celerators such as LHC,the main problems are (1) radiation hardness is not yet s atisfactory,(2) light yield is low. When some impurities are removed from the raw materials,the origin of radiation damage is not related to the purity of the raw material but to structural defect s produced during the growth process.These defects result from the leakage of le ad ( V c(Pb)) and oxygen ( V o) and introduce local charge unbalance that ea sily traps electrons or holes and act as temporary color centers under irradiati on. So doping different ions to compensate charge and suppress the existing defe cts is necessary.展开更多
Gel-incorporated single-crystals provide unique combinational properties of long-range order and composite structures, which is desired for semiconducting and conducting materials. However, the reported gel-incorporat...Gel-incorporated single-crystals provide unique combinational properties of long-range order and composite structures, which is desired for semiconducting and conducting materials. However, the reported gel-incorporated single-crystals are limited to insulating crystals. Here, we examine crystals of two typical semiconductors, lead sulfide （PbS） and lead iodide （Pbl2）, grown from both silica gels and agarose gels. In all the four crystal-gel pairs, single-crystals of the cubic phase of PbS and the hexagonal phase of Phi2 were obtained according to the X-ray diffraction analysis. Dissolution of the gel-grown crystals exposed insoluble materials with the shape similar to the original crystals, indicative of gelincorporation inside the crystals. As such, this work creates a facile strategy to construct 3D heterostructures inside serniconducting single-crystals without destroying their long-range order.展开更多
A cross-linkable comonomer containing a diacetylene group,named dimethyl 4,4＇-（buta-l,3-diyne-l,4-diyl）dibenzoate（DA） was synthesized and copolymerized with dimethyl succinate and 1,4-butanediol to prepare a seri...A cross-linkable comonomer containing a diacetylene group,named dimethyl 4,4＇-（buta-l,3-diyne-l,4-diyl）dibenzoate（DA） was synthesized and copolymerized with dimethyl succinate and 1,4-butanediol to prepare a series of slightly cross-linked PBS copolyesters（PBDASx）.The chemical structure,crystallization and Theological behaviours of PBDASx were well investigated.Compared to neat PBS,PBDASx showed the greatly increased crystallization rate because of the promoting nucleation of the cross-linking domains,and the XRD results indicated that it had no influence on crystallization structure of PBS.The rheological behaviours indicate that PBDASx possessed higher viscosity than neat PBS even at high shear rate and temperature.PBDAS0.3 exhibited better comprehensive properties than neat PBS,which will widen applications of PBS.展开更多
文摘When lead tungstate scintillating crystals are used as dense and fast radiat ors for γ ray detectors in high radiation environment in future high energy a c celerators such as LHC,the main problems are (1) radiation hardness is not yet s atisfactory,(2) light yield is low. When some impurities are removed from the raw materials,the origin of radiation damage is not related to the purity of the raw material but to structural defect s produced during the growth process.These defects result from the leakage of le ad ( V c(Pb)) and oxygen ( V o) and introduce local charge unbalance that ea sily traps electrons or holes and act as temporary color centers under irradiati on. So doping different ions to compensate charge and suppress the existing defe cts is necessary.
基金supported by Zhejiang Province Natural Science Foundation(No.LZ13E030002)the 973 Program(No. 2014CB643503)+1 种基金the National Natural Science Foundation of China (Nos.51222302,51373150,51461165301)Fundamental Research Funds for the Central Universities
文摘Gel-incorporated single-crystals provide unique combinational properties of long-range order and composite structures, which is desired for semiconducting and conducting materials. However, the reported gel-incorporated single-crystals are limited to insulating crystals. Here, we examine crystals of two typical semiconductors, lead sulfide （PbS） and lead iodide （Pbl2）, grown from both silica gels and agarose gels. In all the four crystal-gel pairs, single-crystals of the cubic phase of PbS and the hexagonal phase of Phi2 were obtained according to the X-ray diffraction analysis. Dissolution of the gel-grown crystals exposed insoluble materials with the shape similar to the original crystals, indicative of gelincorporation inside the crystals. As such, this work creates a facile strategy to construct 3D heterostructures inside serniconducting single-crystals without destroying their long-range order.
基金supported financially by the National Natural Science Foundation of China (Nos. 21634006 and 51121001)the Program for Changjiang Scholars and Innovative Research Teams in University of China (No. IRT1026)
文摘A cross-linkable comonomer containing a diacetylene group,named dimethyl 4,4＇-（buta-l,3-diyne-l,4-diyl）dibenzoate（DA） was synthesized and copolymerized with dimethyl succinate and 1,4-butanediol to prepare a series of slightly cross-linked PBS copolyesters（PBDASx）.The chemical structure,crystallization and Theological behaviours of PBDASx were well investigated.Compared to neat PBS,PBDASx showed the greatly increased crystallization rate because of the promoting nucleation of the cross-linking domains,and the XRD results indicated that it had no influence on crystallization structure of PBS.The rheological behaviours indicate that PBDASx possessed higher viscosity than neat PBS even at high shear rate and temperature.PBDAS0.3 exhibited better comprehensive properties than neat PBS,which will widen applications of PBS.
