用核方法研究β-氧化铝陶瓷

用(P,P′γ)和~1H(~(15)N,αγ)~(12)C反应以及He~+离子背散射方法分析了β-氧化铝陶瓷样品。结果表明,其近表面区域Na/Al比值为0.07-1.16;O/Al比值为1.23-4.33。钠含量平均比单晶体多33％,锂浓度与原料中的锂量一致,钠和锂的分布均有不对称性。样品的吸水效应具有可逆性,水沾污直接影响表面区的钠含量和浓度分布。这种无破坏性的定量测量方法可以成β-氧化铝陶瓷配方和制造工艺最佳化的快速检测手段。     

高效液相色谱法分离多管藻中光合色素

以红藻多管藻(Polysiphonia urceolata Grev.)为材料,采用高效液相色谱(HPLC)法摸索了藻体色素分离和纯化的条件.用丙酮-乙醇(1:1,v:v)提取12h,提取物用HPLC法纯化,流动相为A(甲醇:0.5mol/L乙酸铵,4:1,v:v,)、B(乙腈:水,9:1,v:v)和C(乙酸乙酯).上样量1mL,流速2mL/min,用二极管阵列检测器(Photodiode Array Detector,PDAD)检测,检测波长为440nm,收集洗脱峰.由洗脱峰的吸收光谱和荧光光谱可知,获得的两个最主要组分分别为叶绿素和类胡萝卜素.为进一步了解多管藻色素的光物理性质,提供了快速简洁的分离纯化色素的方法.     

红外光谱法快速测定松香改性酚醛树脂中的松香含量

本文叙述用红外光谱法快速测定松香改性酚醛树脂中的松香含量。本法是以测定松香酸的C=0伸缩振动吸收带的强度来测量松香的含量。基于松香改性酚醛树脂的红外光谱与松香和酚醛树脂混合物的红外光谱两者十分相近。因此以不同松香含量的松香—酚醛树脂的共混样作标样,然后以薄膜法测定,分别测得E_(1700)/E_(1600)的比值,由松香含量和相应的消光值的比值绘制曲线,由此计算样品中松香含量。     

摇蚊基因组DNA的提取方法研究

采用动物基因组DNA快速抽提试剂盒法、SDS法、CTAB法、NaCl法4种方法提取摇蚊基因组DNA.通过紫外分光光度计分别检测所得样品DNA在波长为260nm和280nm的吸光值,根据A260/A280的比值检测其纯度和浓度.采用PCR技术获得摇蚊COI基因,用琼脂糖凝胶电泳检测PCR-COI.综合分光光度法与电泳结果筛选出最适合提取摇蚊基因组DNA的方法.结果表明:SDS法所得样品DNA纯度最高,试剂盒法所得DNA浓度最大.同时综合比较DNA纯度与浓度分析得出:试剂盒法SK8222(改良)提取摇蚊基因组DNA为最佳方法,其次为SDS法或CTAB法(改良).     

锰结核中^2^3^1Pa分离测定法的研究

着重研究了锰结核样品中Pa的分离条件,建立了~(231)Fa分离的流程。锰结核样品加入示踪剂~(232)U-~(228)Th和~(233)Pa,在 0.05 mol/l HF 存在下用盐酸和硝酸溶解,离心除去不溶残渣,溶解液蒸干用1mol/l HNO_3提取,在pH=7 下使 Fe(OH)_3 沉淀后进行Th-Pa-U 的离子交换色层分离。Pa用 0 mol/l HCl 0.05 mol/l HF 洗脱,洗脱液用0.5 mol/l TTA-苯萃取纯化和制源,比较了~(231)Fa α能谱法和α计数法测试的结果,实测了一个碳酸盐标准样品的~(231)Fa/~(235)U 法年龄为(85±10)×10~3 y与~(230)Th/(234)u法的平均年龄(84±4)×10~3 y 是一致的。Pa的化学回收率为78～86％。     

简并四波混频中的第三束共轭光

自1977年 Hellwarth 提出并验证四波混频相位共轭以来,人们对它的作用机制进行了很多研究,普遍认为共轭光包括两部分:E_(c1)是抽运光 E_1经信号光(探测光)E_p 和抽运光 E_2形成的位相光栅衍射产生的;E_(c2)是抽运光 E_2经信号光 E_p 与抽运光 E_1形成的位相光栅衍射产生的,总的共轭光则是这两部分的相干叠加.我们在实验中观察到了第三束共轭光:E_(c3),其响应时间要大于 E_(c1)和 E_(c2),而强度远小于 E_(c1)和 E_(c2).     

照相染料在氯化银晶体上光谱增感作用的计时电位法研究

以电沉积在银电极上的氯化银为研究模型,用计时电位法研究了文题内容。结果表明,计时电位法可简单、方便地测定卤化银吸附增感染料后的阴极化还原过渡时间τ和还原电位E_(1/2)~*。由于生成电还原惰性络合物,显著地影响氯化银的τ和E_(1/2)~*,并和增感染料的结构与浓度密切有关。τ和E_(1/2)~*的变化大小与增感染料对氯化银乳剂的光谱增感作用之间有一定的关系。     

GaAs中Te施主杂质的EER谱

本文用EER谱技术,在室温下对掺Te砷化镓(n=1×10~(18)cm~(-3))样品进行了测量,对杂质的ER谱结构E_1进行了分析,提出了电调制浅杂质态的物理模型,用F-K效应定性解释了杂质的ER谱.通过与未掺杂GaAs(n=7.7×10~(14)cm~(-3))的ER谱相比较,定出了E_1结构的线型及位置.     

灭菌乳中糠氨酸含量测定方法的改进

样品经过水解、纯化,将杂质与被测组分分离。利用DIAMONSIL(钻石)C185μm4.6×250mm柱,以0.1%三氟乙酸(A)和甲醇(B)通过梯度洗脱,在280nm下测定糠氨酸的含量,此法定量准确、精密度高。     

根据两相声速模量理论测定纤维非晶区取向因素f_(am)的变化

一般的高聚物材料是一种包含有晶相和非晶相的两相体系。众所周知,用X线衍射法可以测定纤维的晶区取向因素f_c,但对于非晶区取向因素f_(am)却还缺乏一种直接和精确的测量方法。在 Moseley 声速取向理论的基础上,Samuels 进一步提出了两相声速模量理论,并推导出以下公式:此处,E_(or)——部分取向试样的实测声速模量;E_(t·c)~0,E_(t·am)~0——分别为试样的晶区和非晶区的特征横向杨氏模量;f_c,f_(am)——试样的晶区和非晶区取向因素;β——试样结晶度。从上式中可以看到,对一定的试样而言,E_(t·c)~0和E_(t·am)~0均为常数,因此只要测出试样的声速模量E_(or)、结晶度β和晶区取向因素f_c,则就可以计算非晶区取向因素f_(am)。我们用高速PET纤维(6000米/分)作为试样,在不同条件下进行紧张热定型处理,然后分别测定E_(or)、β和f_c,并进一步计算f_(am)。从实验结果可以得到三点结论:1.随着热定型温度的提高,试样的结晶度提高,但同时非晶区取向因素f_(am)随之下降.2.f_(am)随着热处理中对试样施加张力的增加而增加,且两者呈线性关系;3.f_(am)随张力而变化的曲线的斜率,在不同的温度下有所不同,温度增高,曲线的斜率也增大。     

稀土发光中心能级的热移位（Ⅰ）

在10—550K的温度范围内首次系统地研究了YAG:Nd~(3+)的斯塔克能级R_1和R_2的热移位。     

Expression, purification and characterization of the soluble CuA domain of cytochrome c oxidase ofParacoccus versutus

The key subunit Ⅱ of cytochrome c oxidase (CcO) contains a soluble binuclear copper center (Cu_A) domain. The Cu_A domain of Paracoccus versutus was cloned, expressed, purified and characterized. The gene encoding the Cu_A domain in pET11d vector was expressed in E. coli BL21 (DE3). The results showed that the Cu_A domain was expressed mostly in inclusion bodies and the Cu_A domain protein synthesized in E. coli cells represents approximately 10 percent of the total cellular proteins. Dissolved in urea, dialyzed and recombined with Cu⁺/Cu²⁺ and purified by the Q-sepharose fast flow anion-exchange column and Sephadex G-75 gel filtration column, the soluble purple-colored protein, which shows a single band in electrophoresis, was obtained. The UV-visible absorption spectrum of Cu_A domain showed that there are intense band at 478 nm and a shoulder peak at 530 nm, and two weak bands at 360 and 806 nm respectively, which can be assigned to the charge transfer and the interactions of obitals of Cu—S and Cu——Cu in the mixed-valence binuclear metal center (Cu₂S₂R₂). The far-UV CD spectrum indicated that this domain is predominantly in β-sheet structure. The fluorescence spectra showed that its maximal excitation wavelength and maximal emission wavelength are at 280 and 345 nm, respectively.     

Tb~(3+)/Ce~(3+)掺杂硼酸盐玻璃的发光性能

采用高温熔融冷却法制备了Tb3+,Ce3+掺杂和Tb3+/Ce3+共掺硼酸盐玻璃,并利用荧光光谱研究了其发光性能。结果表明:在紫外光激发下,Tb3+掺杂玻璃最强发射峰位于545 nm;Ce3+掺杂玻璃的发射光谱是峰值位于387 nm附近的不对称宽带;Tb3+/Ce3+共掺玻璃的发射光谱是由380 nm附近的不对称宽带和491,545,588,623 nm附近的4个发射峰组成;在Tb3+/Ce3+共掺玻璃中,Ce3+是Tb3+的高效敏化剂,Tb3+的发射强度是Tb3+掺杂玻璃的8倍以上。     

Multiple transport modes of the cardiac Na+/Ca2+ exchanger

The cardiac Na+/Ca2+ exchanger (NCX1; ref. 2) is a bi-directional Ca2+ transporter that contributes to the electrical activity of the heart. When, and if, Ca2+ is exported or imported depends on the Na+/Ca2+ exchange ratio. Whereas a ratio of 3:1 (Na+:Ca2+) has been indicated by Ca2+ flux equilibrium studies, a ratio closer to 4:1 has been indicated by exchange current reversal potentials. Here we show, using an ion-selective electrode technique to quantify ion fluxes in giant patches, that ion flux ratios are approximately 3.2 for maximal transport in either direction. With Na+ and Ca2+ on both sides of the membrane, net current and Ca2+ flux can reverse at different membrane potentials, and inward current can be generated in the absence of cytoplasmic Ca2+, but not Na+. We propose that NCX1 can transport not only 1 Ca2+ or 3 Na+ ions, but also 1 Ca2+ with 1 Na+ ion at a low rate. Therefore, in addition to the major 3:1 transport mode, import of 1 Na+ with 1 Ca2+ defines a Na+-conducting mode that exports 1 Ca2+, and an electroneutral Ca2+ influx mode that exports 3 Na+. The two minor transport modes can potentially determine resting free Ca2+ and background inward current in heart.     

Enhanced conversion efficiency of Yb2+–Yb3+-codoped glass as spectral converter for photovoltaic application

We propose a kind of Yb²⁺–Yb³⁺-codoped glass, which is used as spectral converter layer to adjust AM1.5 solar spectrum for a better match with silicon bandgap. The energy-level rate equations and power transmission equations are established to analyze the down-conversional effect of the codoped glass on solar spectrum. The numerical results show that with proper doping concentration and thickness the glass layer may improve conversion efficiency by about 12 %. Moreover, we also apply the modified spectrum as excitation source of solar cell in a simulation platform, and reveal that there is about 15 % improvement in practical cells.     

硅烷化溶剂对TiO2/Fe-MCM-41复合光催化剂吸附性能的影响

在不同条件下用KH-550硅烷偶联剂对介孔分子筛Fe—MCM-41表面进行化学修饰后,以Fe—MCM-41分子筛为载体负载TiO2纳米溶胶。实验发现在硅烷化处理时,选择不同极性的溶剂对复合光催化剂的吸附性能有显著影响。利用XRD,固体漫反射UV—Vis吸收光谱,FT—IR,低温N2吸附-脱附等对分子筛进行了表征。结果表明：在不同的溶剂中,Fe—MCM-41分子筛在KH-550化学修饰时硅烷化程度不同。与无水乙醇等极性较强的溶剂所制的样品相比,正己烷为溶剂的TiO2—Fe—MCM-41正己烷样品具有更强的吸附能力,对TiO2纳米粒子具有更好分散能力。     

300-Myr-old magmatic CO2 in natural gas reservoirs of the west Texas Permian basin

Except in regions of recent crustal extension, the dominant origin of carbon dioxide in fluids in sedimentary basins has been assumed to be from crustal organic matter or mineral reactions. Here we show, by contrast, that Rayleigh fractionation caused by partial degassing of a magma body can explain the CO2/3He ratios and delta13C(CO2) values observed in CO2-rich natural gases in the west Texas Val Verde basin and also the mantle 3He/22Ne ratios observed in other basin systems. Regional changes in CO2/3He and CO2/CH4 ratios can be explained if the CO2 input pre-dates methane generation in the basin, which occurred about 280 Myr ago. Uplift to the north of the Val Verde basin between 310 and 280 Myr ago appears to be the only tectonic event with appropriate timing and location to be the source of the magmatic CO2. Our identification of magmatic CO2 in a foreland basin indicates that the origin of CO2 in other mid-continent basin systems should be re-evaluated. Also, the inferred closed-system preservation of natural gas in a trapping structure for approximately 300 Myr is far longer than the residence time predicted by diffusion models.     

胭脂鱼（Myxocyprinus asiaticus）幼鱼在河口区的生存适应性实验研究

对胭脂鱼（Myxocyprinus asiaticus）幼鱼在不同盐度、不同氮磷营养盐组合浓度下进行96 h急性胁迫实验,研究其在胁迫条件下的存活率及肝脏组织中超氧化物歧化酶（SOD）和腮丝组织中Na⁺/K⁺-ATP酶活性的反应,探讨其在模拟河口区水域的适应能力.实验结果显示,在96 h的盐度急性胁迫中,在盐度小于10的情况下,胭脂鱼存活率可达100%;盐度3和盐度0组的SOD活性和Na⁺/K⁺-ATP酶活性始终无显著差异（p>0.05）;在96 h的氮磷急性胁迫中,当水体中氮磷浓度均优于Ⅳ类水质标准时,胭脂鱼的存活率可达100%;Ⅳ类水质组的SOD活性在48 h时显著高于Ⅱ类和Ⅲ类水质组（p<0.05）;上述实验结果表明,胭脂鱼在盐度小于3,水质中氮磷浓度优于Ⅲ类水质标准时生理反应比较平稳,具有较好的生存适应性.通过对比现实河口地区的水质状况,目前长江河口南支青草沙以西水域的水质条件可以满足胭脂鱼幼鱼的生存.     

微观sdIBM - 2下~(188)Os核的研究

本文在微观sdIBM - 2框架下 ,计算了1 88Os核的能谱、约化E2跃迁矩阵元、E2跃迁玻色子结构函数 (BSF)以及第一个 2 +态到基态的跃迁电荷密度 (TCD)。理论结果与实验值作了比较 ,理论能谱成功地再现了实验能谱 ,低能态间的约化E2跃迁矩阵元以及 2 +1 态到0 +1 态的跃迁电荷密度与相应的实验值符合也较好 ,表明此模型对该核的较低能态描述较为合理。     

Gd_2O_3中掺杂Eu~(3+)和Yb~(3+)荧光粉的制备及荧光性能

采用溶胶-凝胶法制备了Gd2O3∶Eu3+,Gd2O3∶Yb3+与Gd2O3∶Eu3+,Yb3+荧光粉,对制备条件进行了研究,且进行了样品的物相表征.结果表明,Yb3+在高掺杂浓度下存在浓度猝灭,Eu3+可以通过共合作能量传递过程和交叉弛豫过程有效地将能量传递给临近的一对Yb3+离子.Gd2O3∶Eu3+,Yb3+在Eu3+的特征激发峰314 nm激发时,可以产生550~750 nm的Eu3+的特征发射和900~1100 nm的Yb3+近红外特征发射两个波段光谱.制备的Gd2O3∶Eu3+,Yb3+荧光粉可以将硅太阳能电池吸收较弱的300~550 nm的高能光子转换为两个响应较好的近红外光子.