2450MHz微波与γ射线联合辐射对大鼠神经胶质细胞的影响

探讨微波及微波联合γ射线照射对大鼠神经胶质细胞凋亡率、线粒体膜电位(MMP)、胞内游离Ca2+和Ca2+-Mg2+-ATP酶活性的影响。将原代神经胶质细胞分为对照组(C)、微波组(M)、电离组(I)和联合组(IM)。M和IM组接受4mW/cm2的微波辐射3d,2h/d;第4天,I和IM组接受5Gy1Gy/min)的γ射线照射。采用Ca2+-Mg2+-ATP酶测试盒检测胞内Ca2+-Mg2+-ATP酶;流式细胞术检测细胞凋亡和MMP;流式细胞术和共聚焦激光扫描显微镜检测胞内游离Ca2+变化。结果发现,与C组相比,I和IM组细胞的凋亡率显著升高,各组细胞MMP未见明显变化;M、I和IM组胞内游离Ca2+明显升高,Ca2+-Mg2+-ATP酶活性显著降低,差异均有统计学意义(p0.05)。结果提示,在本试验条件下,2450MHz微波可使胞内Ca2+显著上升,Ca2+-Mg2+-ATP酶活性显著降低;未观察到微波与γ射线照射大鼠神经胶质细胞的联合作用。     

罗非鱼片在冷藏过程中的品质变化研究

综合研究冷藏过程中罗非鱼片品质变化的相关几项指标,包括感官值、pH 值、挥发性盐基氮(TVB-N)值、K 值、Ca2+-ATP 酶活性值、脂肪氧化(TBA)值。结果表明：TVB-N 值、K 值、Ca2+-ATP 酶活性值和感官值有很好的相关性,表现为：罗非鱼片品质开始变差出现在第5 天左右,鱼片感官值下降到16,K 值增加到29.5%,TVB-N 值增加到15.775mg/100g,Ca2+-ATP 酶活性降低了27.24%;鱼片品质开始恶化出现在第12 天左右,感官值下降到8,TVB-N 值为29.96mg/100g,K 值为54%,Ca2+-ATP 酶活性降低了53.36%。通过综合分析这些指标可评价冷藏过程中罗非鱼片的品质变化。     

改性层状结晶硅酸钠对钙镁离子交换的动力学研究

改性层状结晶硅酸钠（Al-SKS-6）是一种通过层状结晶硅酸钠（SKS-6）改性的性能优良的洗衣粉助剂。对其进行合成并表征,考察了pH、温度和时间对钙镁交换能力的影响及动力学研究。当pH在10左右时,钙离子和镁离子交换能力达到最大,分别为352 mg/g和405 mg/g,可满足洗衣粉的实际要求。Al-SKS-6对钙镁离子的交换是一个快速交换过程,在5 min时,钙镁离子交换能力可达到30 min时的90%,10 min基本可以达到交换平衡,交换过程符合二级动力学方程,且随着温度的升高,Al-SKS-6对钙镁离子交换能力增大。     

Intense blue-emitting Ca₂PO₄Cl:Eu²⁺ phosphor for near-ultraviolet converting white light-emitting diodes

A blue phosphor Ca2PO4Cl:Eu2+(CAP:Eu2+) was synthesized by solid state reaction.The Ca2PO4Cl:Eu2+ exhibited high quantum efficiency and excellent thermal stability.The luminescent intensity of Ca2PO4Cl:Eu2+ was found to be 128% under excitation at 380 nm,149% under 400 nm,and 247% under 420 nm as high as that of BaMgAl10O17:Eu2+.The optimal doping concentration was observed to 11 mol.% of CAP:Eu2+.The energy transfer between Eu2+ ions in CAP were occurred via electric multipolar interaction,and the critical transfer distance was estimated to be 1.26 nm.A mixture of blue-emitting Ca2PO4Cl:Eu2+,green-emitting(Ba,Sr)2SiO4:Eu2+ and red-emitting CaAlSiN3:Eu2+ phosphors were selected in conjunction with 400 nm chip to fabricate white LED devices.The average color-rendering index Ra and correlated color temperature(Tc) of the white LEDs were found to be 93.4 and 4590 K,respectively.The results indicated that it was a promising candidate as a blue-emitting phosphor for the near-UV white light-emitting diodes.     

Analytical Behavior of Fura-2 and Its Determination of [Ca2+]i in Lymphocytes Treated with Cefotaxime

The interaction of Fura-2 with Ca2+ is studied using steady fluorescence technique.The effect of pH on the spectra behavior of Fura-2 in the presence of Ca2+ is investigated,the excitation maxima(340 nm)and the isobestic point(360 nm)for the fluorescence spectra of Fura-2 depend on pH.At different temperatures the apparent dissociation constants(Kd)of Fura-2-Ca2+ complex are examined,Kd is found to decrease with increasing temperatures(20 ℃,37 ℃,50 ℃)and ΔH is calculated to be 21.16 kJ/mol by using the Van't Hoff equation at pH 7.4 for all the temperatures tested.The determination of intracellular Ca2+ concentration([Ca2+]i)in lymphocyte is developed by using Fura-2 as a fluorescence probe in the presence of Cefotaxime at 37 ℃ and pH 7.4.     

难免离子对中低品位钙镁质磷矿石反浮选的影响

采用浮选试验,结合溶液化学计算、方差分析、扫描电镜和X射线荧光光谱分析等手段研究难免离子对中低品位钙镁质磷矿石反浮选的影响. 研究结果表明:矿浆中Ca²⁺和Mg²⁺会降低浮选磷精矿中P₂O₅含量而提高MgO含量,原因是Ca²⁺和Mg²⁺会沉淀捕收剂解离的RCOO^-,降低其有效浓度;SO₄^2-会降低磷精矿中P2O5回收率,其作用机理是由于SO₄²-能与Ca²⁺作用生成硫酸钙沉淀并覆盖在氟磷灰石和白云石表面,增强氟磷灰石的可浮性,导致氟磷灰石随白云石一起浮出;PO₄^3-对浮选影响较小;Ca²⁺、Mg²⁺、SO₄^2-和PO₄^3-对磷精矿中SiO₂、Al₂O₃和Fe₂O₃含量影响较小. 由于Ca²⁺和SO₄^2-分别对磷精矿P₂O₅品位和P₂O₅回收率影响显著,因此在回水利用过程中需控制矿浆中Ca²⁺和SO₄^2-浓度,降低其对浮选的影响.     

Mg-9Li双相合金中共晶组织的形成及力学反应

在Mg-9Li双相合金中添加0.5wt.% Ca元素,通过磁悬浮熔炼及铜模吸铸方法熔炼制备了共晶型Mg-9Li-0.5Ca合金。组织观察表明,常规Mg-9Li双相合金中形成的?-Mg相为粗大短板条状,取向随机、均匀无序分布于?-Li 基体中。而Mg-9Li-0.5Ca合金中形成了棒状交替排列的（?-Mg ?-Li）共晶团组织,在共晶团内?-Mg相呈长纤维状（长径比~100）、并以一定取向定向排列;相比于Mg-9Li合金,共晶?-Mg相纤维间距及纤维直径显著减小、组织明显细化,?-Mg相体积分数显著增加;同时,大量纳米、亚微米级Mg2Ca颗粒均匀弥散分布于?-Mg、?-Li晶粒内及两相界面上。由此导致具有该共晶组织的Mg-9Li-0.5Ca合金相比于Mg-9Li合金室温拉伸屈服强度提高3%、抗拉强度提高3.5%,伸长率提高50%,力学性能显著增加。分析表明,微量Ca元素的添加和铜模吸铸产生的较快的冷却速度,诱发Mg-9Li双相中细小（?-Mg ?-Li）共晶组织的形成,显著提高力学性能。     

高Q值(1-x)(Sr0.2Nd0.208Ca0.488)TiO3-xNd(Ti0.5Mg0.5)O3微波陶瓷的微结构及介电性能研究

采用固相法制备了(1-x)(Sr_0.2Nd_0.208Ca_0.488)TiO₃-xNd(Ti_0.5Mg_0.5)O₃(0.3≤x≤0.4, SNCT-NTMx)系微波介质陶瓷材料, 并研究了该体系的相组成、显微结构、烧结性能和微波介电性能之间的关系。结果表明: 在x = 0.3~0.35范围内, SNCT-NTMx陶瓷形成了正交钙钛矿固溶体, 并伴随有少量未知第二相; 当x增至0.4时, 第二相含量有所增加。介电性能研究结果显示: 随着x的增加, 体系介电常数(ε_r)减小, 但品质因子(Q×f)得到改善; 此外, 体系谐振频率温度系数(τ_f)随NTM含量的增加逐渐向负值方向移动。当x = 0.35, 陶瓷样品在1520℃烧结4 h 得到的微波介电性能较优: ε_r=50.1, Q×f =44910 GHz, τ_f= -1.7×10^-6/℃。