南海北部白云深水区之基础地质

白云深水区具有复杂而特殊的地质条件：位于中生代俯冲带的构造软弱带、新

离子注入GaAs实现双包层掺镱光纤激光器被动调Q锁模

用离子注入的半绝缘GaAs晶片作为吸收体和输出镜,在双包层掺镱光纤激光器上实现了调Q锁模.离子注入的能量为400keV的As+离子,注入剂量为1016/cm2,然后在600℃下退火20min.当抽运功率为5W时,脉冲平均输出功率为200mW,调Q包络重复频率为50kHz,半高宽为4μs,锁模脉冲重复频率为15MHz。

Optimization of evanescent wave imaging for the visualization of protein adsorption layers

We have optimized the settings of evanescent wave imaging for the visualization of a protein adsorption layer. The enhancement of the evanescent wave at the interface brought by the incident angle, the polarized state of light beam as well as a gold layer is considered. In order to improve the image contrast of a protein monolayer in experiments, we have optimized three factors-the incident angle, the polarization of light beam, and the thickness of an introduced thin gold layer with a theoretical simulation.

长白山四种森林土壤呼吸的影响因素

2004年5-10月,研究了非生物因素(温度、土壤含水量)和生物因素(微生物量碳和植被类型)对长白山北坡四个垂直植被带阔叶红松(Pinus koraiensis)林、红松云冷杉(Picea jezoensis,Abies nephrolepis)林、岳桦(Betula ermani)云冷杉林和岳桦林的土壤呼吸的影响。结果表明:4种森林的土壤呼吸与土壤温度、大气温度之间都呈极显著(p<0.01)指数相关关系;土壤呼吸与土壤含水量没有明显的相关关系;土壤微生物量碳随季节变化有相似的变化规律,即单峰型曲线,峰值出现在8月份;土壤呼吸的月平均值和土壤微生物量碳之间都呈线性相关,但均未达到显著水平;不同月份植被类型对土壤呼吸的影响没有明显的规律。

黄土高原南部3种农田土壤剖面坚实度的变化规律

为了揭示黄土高原南部地区不同质地类型土壤剖面坚实度的变化及其与土壤含水率的定量关系,以黄墡土、土娄土、裸露在地表的粘化层耕作剖面为研究对象,定位观测其0~45 cm土壤坚实度与含水率的变化。结果表明,黄墡土、土娄土、裸露在地表粘化层耕作剖面的犁底层平均坚实度均大于耕层,犁底层平均坚实度较耕层分别高194.8%,87.3%,10.4%;剖面土壤质地越粘其平均坚实度越大;土壤坚实度与含水率呈负相关关系;土壤坚实度变化速率为0时,以上3种土壤剖面临界含水率分别为0.1712,0.1757,0.1835;质地不同的土壤剖面坚实度时空变化特征有差异,其中黄墡土剖面0~20 cm土层土壤坚实度为350~500 kPa,受土壤含水率变化的影响较小;20~30 cm土层土壤的坚实度为500~1400 kPa,不易受外界环境影响;30 cm以下土层土壤坚实度为700~1600 kPa,受土壤含水率变化影响较大。土娄土剖面0~40 cm土层土壤坚实度为600~1200 kPa,受含水率变化影响较大;40 cm以下土层土壤坚实度稳定在1 800 kPa左右。粘化层剖面0~15 cm土层土壤坚实度在2000 kPa左右,受环境影响较...

细河河水及其沿岸地下水水质的有机污染特征

调查了沈阳市细河河水及其沿岸地下水水质中石油类和美国环保局(USEPA)"黑名单"上的16种优先控制多环芳烃(PAHs)的有机污染现状,评价细河污染带来的生态风险。结果表明:细河河水中石油类浓度和16种PAHs总浓度范围分别为0.031～1.819mg.L-1和0.026～0.384μg.L-1,平均浓度分别为1.007mg.L-1和0.151μg.L-1;细河沿岸地下水中石油类浓度和16种PAHs总浓度范围分别为0.020～0.987mg.L-1和0.051～0.389μg.L-1,平均浓度分别为0.364mg.L-1和0.133μg.L-1;细河河水和地下水中的石油类污染严重;河水中的PAHs浓度在流经规模较大的城镇或乡镇处出现高值点,苯并(b)荧蒽和苯并(k)荧蒽在河水与地下水中的检出率较高,对水生生态系统健康构成了潜在的威胁。

A third-generation H2O2 biosensor based on horseradish peroxidase-labeled Au nanoparticles self-assembled to hollow porous polymeric nanopheres

A novel third-generation biosensor for hydrogen peroxide (H2O2) was developed by self-assembling gold nanoparticles to hollow porous thiol-functionalized poly(divinylbenzene-co-acrylic acid) (DVB-co-AA) nanospheres. At first, a cleaned gold electrode was immersed in hollow porous thiol-functionalized poly(DVB-co-AA) nanosphere latex to assemble the nanospheres, then gold nanoparticles were chemisorbed onto the thiol groups of the nanospheres. Finally, horseradish peroxidase (HRP) was immobilized on the surface of the gold nanoparticles. The immobilized horseradish peroxidase exhibited direct electrochemical behavior toward the reduction of hydrogen peroxide. The resulting biosensor showed a wide linear range of 1.0 mu M-8.0 mM and a detection limit of 0.5 mu M estimated at a signal-to-noise ratio of 3. Moreover, the studied biosensor exhibited high sensitivity, good reproducibility, and long-term stability.