文献 | 量子荧光|微型光纤光谱仪-ag贵宾会

番茄是茄果类蔬菜中非常重要的一种蔬菜,也是我省目前蔬菜种植业中的主要栽培作物之一。随着人们消费水平的提高和对无公害蔬菜需求量的增加,利用设施栽培解决蔬菜淡季供应成为重要措施之一。但是,设施栽培的出现必将导致蔬菜植物生长的小气候环境因子(光强、温度、湿度和 co2浓度)发生显著性的改变,对于本身喜光喜温特性显著的温室番茄生产更是如此。然而,有关番茄的研究多数集中在种子生理，生长发育生理。开花结实生理。壮苗生理，嫁接生理。矿质营养生理等方面，其中也涉及到一些的番茄光合特性测试报道,而且主要是环境因子对稳态光合响应特性的影响,对露地和设施番茄生产有着重要的指导意义。我们知道,无论是露地还是设施内,小气候因子会呈现连续性或骤然性的变化,植物叶片的光合系统也会跟随响应,即呈现瞬态响应对植物的光合作用产生显著的影响。因此研究中以瑞士先正达公司‘保罗塔’番茄为试材采用 ciras-2 光合测试系统和 qe65000 光纤光谱仪同步测试分析了番茄叶片光合系统各个参数的动态响应。分析了动态的光环境对番茄叶片光合作用的影响探索了动态光环境下限制光合作用的原因。

在蓝光led照射光强阶跃与反阶跃下,采用ciras-2光合测试系统和qe65000光纤光谱仪,同步测试分析了番茄叶片光合系统的co2 吸收速率pn，胞间co2浓度c，气孔导度gs，叶绿素荧光f680参数的动态响应，光强发生阶跃升高时,各阶跃阶点或起点下番茄叶片pn动态进程均呈现从原稳态到终稳态趋饱和增加趋势,ci 均与pn 呈镜像对称的变化趋势,gs均呈现轻微的先下降后回升的变化趋势,f680 均呈现轻微起伏式骤然升高趋势;而光强发生反阶跃下降时,各反阶跃落点或起点下番茄叶片pn 的动态进程均与光强阶跃升高时相反。在200 μmol·m-2·s-1的相同阶跃量下,随着阶跃起点的增加,pn 从原稳态至终稳态的增幅逐渐减小。综合分析表明,在光强阶跃升高后,通过对叶绿素荧光f680动态变化计算的非饱和激发光下的实际光化学效率y(ii)′ 随着光强阶跃量的增加呈现趋饱和增加趋势,这表明与光能电子传递速率有关的光强水平阶跃升高会给光合碳吸收提供更多的能量驱动力,从而表现出pn 从原稳态到终稳态的趋饱和增加;而在光强阶跃升高后gs 均维持在较高水平,虽在很短时间内有小幅下降波动,但是对co2 进入胞间以及pn 的动态进程无显著影响;可是在光强阶跃升高后ci下降幅度较大,与光合暗反应对胞间co2 的快速吸收消耗有关,会对pn 的动态进程有一定程度影响。

with strong optical absorptivity and a widely tunable bandgap, graphene is an attractive material for optical and optoelectronic devices. [ 1,2 ] recently, emerging graphene quantum dots (gqds), single- or few-layer graphene only several nanometers in size, have been implemented in bandgap engineering due to quantum confinement [ 3,4 ] and edge effects, [ 5 ] which potentially can be exploited in new potential applications of graphene. specifically, fluorescent gqds with tunable emission are considered to be next-generation nanomaterials as a potentially inexpensive and safe alternative to semiconductor quantum dots (qds). [ 6,7 ] moreover, the chemical inertness and excellent biocompatibility of gqds make them attractive for use in bio-sensor, bio-imaging, and photovoltaic applications. [ 8–13 ] however, currently available gqds have several drawbacks, including i) limited synthesis methods that provide desired optical properties (i.e., quantum yields); ii) the lack of a mass production method to create gqds with uniform sizes and shapes without significant loss of their optical properties; iii) difficulty controlling the emission wavelength of the photoluminescence (pl); and iv) debate over the pl mechanism and contraints on the diversity of applications.

nio/zno heterostructures were fabricated on fto/glass and bulk hydrothermal zno substrates by pulsed laser deposition. x-ray diffraction and room temperature (rt) raman studies were consistent with the formation of (0002) oriented wurtzite zno and (111) oriented fcc nio. rt optical transmission studies revealed bandgap energy values of ~3.70 ev and ~3.30 ev for nio and zno, respectively and more than 80% transmission for the whole zno/nio/fto/glass stack over the majority of the visible spectrum. lateral p-n heterojunction mesas (~6mm x 6mm) were fabricated using a shadow mask during pld growth. n-n and p-p measurements showed that ti/au contacting gave an ohmic reponse for the nio, zno and fto. both heterojunctions had rectifying i/v characteristics. the junction on fto/glass gave forward bias currents (243ma at 10v) that were over 5 orders of magnitude higher than those for the junction formed on bulk zno. at ~ 10-7 a (for 10v of reverse bias) the heterojunction leakage current was approximately two orders of magnitude lower on the bulk zno substrate than on fto. overall, the lateral p-nio/n- zno/fto/glass device proved far superior to that formed by growing p-nio directly on the bulk n-zno substrate and gave a combination of electrical performance and visible wavelength transparency that could predispose it for use in various third generation transparent electronics applications.