用等压法研究了298.15 K下L iC l-L i2B4O7-H2O体系在不同L iB4O7质量摩尔浓度时的等压平衡浓度,水活度;计算了L iC l和L i2B4O7混合盐溶液的渗透系数等热力学性质.用298.15 K下的实验数据对P itzer离子相互作用模型进行了参数化研究,...用等压法研究了298.15 K下L iC l-L i2B4O7-H2O体系在不同L iB4O7质量摩尔浓度时的等压平衡浓度,水活度;计算了L iC l和L i2B4O7混合盐溶液的渗透系数等热力学性质.用298.15 K下的实验数据对P itzer离子相互作用模型进行了参数化研究,拟合求取了298.15 K下P itzer离子相互作用参数,用获得的参数计算了L iC l和L i2B4O7在L iC l-L i2B4O7-H2O体系中的活度系数.P itzer模型计算的渗透系数值与实验结果一致.展开更多
Barium metaborate (BaB 2O 4) exists in two forms the high temperature for m α phase and the low temperature form β phase,with the phase transition poi nt at around 925℃.The low temperature phase (β BBO) is an exce...Barium metaborate (BaB 2O 4) exists in two forms the high temperature for m α phase and the low temperature form β phase,with the phase transition poi nt at around 925℃.The low temperature phase (β BBO) is an excellent NLO cryst al for UV region,while the high temperature one (α BBO) is known as a good bir efringent material.α BBO crystal possesses better transparency in the ultravio let region compared with commonly used YVO 4 and CaCO 3 crystals.However,due t o phase transition problem,it is difficult to grow single α BBO crystals by D CZ method,which restricts its wider application.α BBO crystal usually cracks upon cooling resulted from phase transition to β phase.Therefore,it is difficult to grow β BBO single crystals directly from pure BaB 2O 4 mel t;however,to grow single crystals of α BBO is not easy,either. Our recent experiments showed that one could avoid cracking of α BBO cryst als by Sr 2+ doping.This minute amount of Sr 2+ plays the role of structure stabilizer,which inhibits structural reconstruction. In this way,Sr 2+ d op ed BBO single crystals do not subject to phase transition from 925℃ down to roo m temperature. We have mow successfully grown out α BBO single crystals 30mm in diameter by D CZ method from Sr x Ba 1- x BO 4 melt with Sr concentration 0.3 0 .5%.The ratation rate is 10 15r/min,pulling speed is 1 2mm/h.Preliminary tests revealed that its structure and physic chemical properties were almost identic al to those grown from pure melts.These Sr 2+ doped α BBO crystals are no w being widely used in optical isolators.展开更多
The new mixed borates with formula(Rb 2 Ca [B 4 O 5 (OH) 4 ] 2 ·8H 2 O and Cs 2 Ca [B 4 O 5 (OH) 4 ] 2 ·8H 2 O)were prepared by reaction Rb (Cs )-borate aqueous solution with CaCl 2 .Two kinds of compounds w...The new mixed borates with formula(Rb 2 Ca [B 4 O 5 (OH) 4 ] 2 ·8H 2 O and Cs 2 Ca [B 4 O 5 (OH) 4 ] 2 ·8H 2 O)were prepared by reaction Rb (Cs )-borate aqueous solution with CaCl 2 .Two kinds of compounds were characterized by chemical analysis,X-ray powder dif fraction,FT-IR spectra and thermal analysis.展开更多
文摘用等压法研究了298.15 K下L iC l-L i2B4O7-H2O体系在不同L iB4O7质量摩尔浓度时的等压平衡浓度,水活度;计算了L iC l和L i2B4O7混合盐溶液的渗透系数等热力学性质.用298.15 K下的实验数据对P itzer离子相互作用模型进行了参数化研究,拟合求取了298.15 K下P itzer离子相互作用参数,用获得的参数计算了L iC l和L i2B4O7在L iC l-L i2B4O7-H2O体系中的活度系数.P itzer模型计算的渗透系数值与实验结果一致.
文摘Barium metaborate (BaB 2O 4) exists in two forms the high temperature for m α phase and the low temperature form β phase,with the phase transition poi nt at around 925℃.The low temperature phase (β BBO) is an excellent NLO cryst al for UV region,while the high temperature one (α BBO) is known as a good bir efringent material.α BBO crystal possesses better transparency in the ultravio let region compared with commonly used YVO 4 and CaCO 3 crystals.However,due t o phase transition problem,it is difficult to grow single α BBO crystals by D CZ method,which restricts its wider application.α BBO crystal usually cracks upon cooling resulted from phase transition to β phase.Therefore,it is difficult to grow β BBO single crystals directly from pure BaB 2O 4 mel t;however,to grow single crystals of α BBO is not easy,either. Our recent experiments showed that one could avoid cracking of α BBO cryst als by Sr 2+ doping.This minute amount of Sr 2+ plays the role of structure stabilizer,which inhibits structural reconstruction. In this way,Sr 2+ d op ed BBO single crystals do not subject to phase transition from 925℃ down to roo m temperature. We have mow successfully grown out α BBO single crystals 30mm in diameter by D CZ method from Sr x Ba 1- x BO 4 melt with Sr concentration 0.3 0 .5%.The ratation rate is 10 15r/min,pulling speed is 1 2mm/h.Preliminary tests revealed that its structure and physic chemical properties were almost identic al to those grown from pure melts.These Sr 2+ doped α BBO crystals are no w being widely used in optical isolators.
文摘The new mixed borates with formula(Rb 2 Ca [B 4 O 5 (OH) 4 ] 2 ·8H 2 O and Cs 2 Ca [B 4 O 5 (OH) 4 ] 2 ·8H 2 O)were prepared by reaction Rb (Cs )-borate aqueous solution with CaCl 2 .Two kinds of compounds were characterized by chemical analysis,X-ray powder dif fraction,FT-IR spectra and thermal analysis.
