金属叶绿素a配位结构的研究

在丙酮溶液中合成得到镧-叶绿素a、钐-叶绿素a和铜-叶绿素a复合物,并研究了它们的紫外可见光谱（UV-Vis）、Fourier红外光谱（FT-IR）和EXAFS结构.镧-叶绿素a、钐-叶绿素a和铜-叶绿素a的UV-Vis谱、FT-IR谱与叶绿素a（含镁）的光谱性质相似,但与脱镁叶绿素a的光谱性质差异很大.证明了La³⁺、Sm³⁺、Cu²⁺已配位到脱镁叶绿素的卟啉环上,形成了镧-叶绿素a、钐-叶绿素a和铜-叶绿素a复合物.通过扩展X射线吸收精细结构谱(EXAFS)研究表明：合成镧-叶绿素a、钐-叶绿素a具有双层夹心结构.La(Ⅲ)、Sm(Ⅲ)夹于两个卟啉环之间, 与上下卟啉环上共八个N原子配位, La-N平均键长0.261 nm,Sm-N平均键长0.243 nm, 而铜-叶绿素a的EXAFS表明为一单层结构,Cu(Ⅱ)与卟啉环中的四个N原子配位,Cu-N平均键长0.197 nm.元素分析也证明镧-叶绿素a、钐-叶绿素a为双层结构,铜-叶绿素a为单层结构.     

抚仙湖叶绿素a的生态分布特征

2001年5月、8月和9月,对云南抚仙湖水体、沉积物、沉积物与水界面的叶绿素a,浮游植物的优势种类、细胞密度的分布和时空变化及其与环境因子的关系进行了研究。采用分光光度法测定叶绿素a浓度。结果表明,水体叶绿素a浓度的分布存在着明显的季节变化,真光层中的动态变化尤其显著,且光照强度对水体中叶绿素a浓度的分布起主导作用。在观测的3个不同季节中,表层叶绿素a浓度,秋季最高,平均为(2.27±0.12)μg/dm3;春季次之,为(1.85±0.20)μg/dm3;夏季最低,为(1.38±0.15)μg/dm3。分析水体中营养元素的分布特征及其与叶绿素a之间的关系,表明磷是抚仙湖浮游植物生长的主要限制因子。沉积物叶绿素a浓度的垂直分布存在明显差异,其浓度在表层和次表层较高,并随沉积深度的增加而降低;浮游植物的分析表明,硅藻门的小环藻是抚仙湖沉积物中叶绿素a的主要来源。而上覆水中叶绿素a浓度与真光层叶绿素a浓度相当的原因,则可能是由水底微型藻类的再悬浮和浮游植物的沉降聚集而导致的。     

淀山湖富营养化控制叶绿素a 基准研究初探

水质基准是制定水质标准的重要依据, 研究以淀山湖为例, 基于淀山湖二十多年来的监测数据, 通过数据分析的方法, 探讨了淀山湖叶绿素a 基准取值方法。结合淀山湖叶绿素a 变化趋势与年内分布特征, 通过参照状态法, 将叶绿素a 分为冬春季节与夏秋季节两个时期, 建议冬春季节基准值为2.0 μg/L, 夏秋季节基准值为5.0 μg/L。并参考太湖总磷推荐基准值, 利用淀山湖总磷与叶绿素a 投入响应关系, 对获得的基准值进行了初步验证。       

风场对太湖叶绿素a空间分布的影响

叶绿素a的浓度是水环境评价的重要参数。根据2005—2009年太湖全湖32个采样点的20次太湖采样数据,结合气象要素资料模拟的太湖风场,探求了风场对太湖叶绿素a空间分布的影响。结果表明:叶绿素a浓度的高值中心位于太湖西北侧、竺山湾以及梅梁湾流域,而太湖东南部的叶绿素a浓度较低;全太湖全年以东南风为主,南部风速较大,北部风速较弱;风场对叶绿素a的输移作用明显,在风场作用下,叶绿素向太湖西北部和北部输移,造成了该地区太湖流域叶绿素浓度普遍偏高。     

夏季西南印度洋叶绿素a分布特征

分析了2011年1月西南印度洋叶绿素a的分布特征及其粒级结构,并结合水动力学环境和营养盐数据探讨了其主要影响因素。结果表明,西南印度洋副热带涡流(IOSG)区表层叶绿素a浓度较低,不超过0.07 mg/m3,次表层叶绿素a浓度最大值所在水层较深,超过100 m;副热带聚集区(SCZ)表层叶绿素a浓度较高(0.164—0.247 mg/m3),次表层叶绿素a浓度最大值出现在50—70 m层。硝酸盐是该海区浮游植物生长的主要限制因素。微微型(pico)粒级的浮游植物占绝对优势,所有站位其对总叶绿素a的平均贡献率为71.1%,微型(nano)粒级次之(24.2%),小型(net)粒级所占比例最小(4.7%),其中IOSG区pico粒级对总叶绿素a的平均贡献率为77.9%,SCZ的pico粒级对总叶绿素a的平均贡献率为66.7%。IOSG区和SCZ海区之间水动力学环境的不同,可能导致了这两个海区叶绿素a的分布特征及粒级结构的较大差异。     

东海赤潮高发区春季叶绿素a和初级生产力的分布特征

2002年4-5月对东海海域进行了综合调查,分析了海区叶绿素a和初级生产力的分布特性．结果表明,大面站表层平均叶绿素a浓度为1．086mg·m-3．分级叶绿素a结果显示．春季东海浮游植物以微型和微微型(<20μm)占优势,其对海区叶绿素a的贡献为64％,超微型浮游植物(<5μm)占浮游植物生物量的27％．营养盐分布和浮游动物的摄食压力影响了叶绿素a及其粒级结构的分布．平均初级生产力为10．091mg·m-3·h-1。赤潮跟踪的R-03、RL-01、RG-01站的平均初级生产力为399．984mg·m-3·h-1．光和营养盐成为叶绿素和初级生产力平面分布的主要限制因子．表层叶绿素a和初级生产力均在调查海区的123·E纵断面冲淡区产生高值区．DC-11站浮游植物生物量异常高,表层叶绿素a达到9．082mg·m-3,初级生产力为128．79mg·m-3·h-1．但并未出现水色异常．     

水分胁迫对小麦叶绿素a荧光诱导动力学的影响

利用调制式荧光动力学分光光度计研究了水分胁迫对小麦叶片及叶绿体的叶绿素α荧光诱导动力学的影响.结果表明,水分胁迫对小麦光合作用的损伤是多部位的,它影响了PSⅠ活性、PSⅡ活性以及CO_2同化.对于PSⅡ的损伤部位除了它的氧化侧处,还可能损伤了PSⅡ反应中心.     

绥宁河生态修复对粒径分级叶绿素a的影响

通过对上海市的苏州河支流绥宁河治理段与非治理段水体叶绿素a分粒级分析,探讨了生态修复对水体粒径分级叶绿素a的影响．结果表明,非治理和对照以及治理采样点微型和微微型浮游植物叶绿素a占总叶绿素a的百分比均值分别为85．232、92．402和95．205％,其中微型浮游植物叶绿素a占总叶绿素a的百分比均值分别为78．460、87．943和87．211％,对全河叶绿素a的贡献平均为84．538％,是该水体叶绿素a生物量的最大贡献者;网采浮游植物对全河叶绿素a的贡献仅为9．054％．生态修复工程试验使网采浮游植物相对生物量减少,微型浮游植物相对生物量保持稳定,而微微型浮游植物相对生物量增多,对超微型浮游植物的影响不大,微型和微微型浮游植物对工程试验的反应最敏感．     

运用叶绿素a荧光诱导动力学技术检测水稻生产潜力

运用叶绿素a荧光诱导动力学技术,检测水稻叶片和叶绿体的PSII原初光转化效率(F_v/F_m)或与此相关可代表PSII潜在活性(F_v/F_o)的参数,结果表明,不同产量水平的水稻品种之间,其叶片和叶绿体的F_v/F_m(或F_v/F_o)的比值,以及光合电子传递速率均有明显差异.此外,在外源Mg~(2+)的存在下,高产水稻品种叶绿体有更高的原初光能转化效率,同时Mg~(2+)对高产品种叶绿体PSII和PSI之间激发能分配的调节能力也较低产品种者高.实验说明Chl a荧光诱导动力学的技术,能够作为一种快速、灵敏和简便的有效方法用于早期检测水稻(或其他作物)的生产潜力.     

热处理对菠菜和上海青类囊体膜及叶绿素稳定性的影响

绿色蔬菜在加工和贮藏过程中发生的颜色劣变与类囊体膜上叶绿素蛋白复合体的稳定性有着密切的关系。本研究以上海青和菠菜为原料,研究了两种绿色蔬菜在热处理过程中类囊体膜溶液热容、多肽组分、叶绿素含量、pH以及蛋白质荧光的变化。结果表明：热处理会导致叶绿素蛋白复合体的降解,类囊体膜溶液pH下降,上海青类囊体膜热稳定性、叶绿素含量的保持优于菠菜类囊体膜。试验结果为我们明确绿色蔬菜颜色劣变的机理以及寻求更好的护绿手段提供了理论基础。     

Adhesion Characteristics of a Novel Synthetic Polydimethylsiloxane for Bionic Adhesive Pads

Materials with appropriate adhesive properties are suitable for the fabrication of bionic adhesive pads. In this study, a novel polydimethylsiloxane （PDMS） material enhanced with two types of crosslinkers, carbon nanotubes and graphene sheets, was fabricated. The Contact Angle （CA） and cross-sectional morphology of the new material were investigated and observed using a CA meter and Scanning Electron Microscopy （SEM）, respectively. CA measurements indicate that the surface energy of the novel material is twice that of the common PDMS material. SEM observations show that carbon nanotubes and graphene sheets are well dispersed in the polymer, a feature that improves the mechanical properties of the new material. The adhesive performance of this novel composite was tested on an in-house fabricated friction machine. Results show that at a preload of only 50 mN, the adhesion of the novel PDMS material is up to -3.7 times that of common PDMS. The maximum macroscale shear strength and normal adhesion reach 4 N·cm^-2 and 1 N·cm^-2, respectively. The adhesive capability of the material is maintained even after hundreds of times of repeated use. This novel material exhibits excellent adhesion, sufficiently high elastic modulus and high repeatability at low preloads.     

Mechanism Interpretation of the Biological Brain Cooling and Its Inspiration on Bionic Engineering

The brain is one of the most important organs in a biological body which can only work in a relatively stable temperature range. However, many environmental factors in biosphere would cause cerebral temperature fluctuations. To sustain and regulate the brain temperature, many mechanisms of biological brain cooling have been evolved, including Selective Brain Cooling (SBC), cooling through surface water evaporation, respiration, behavior response and using special anatomical appendages. This article is dedicated to present a summarization and systematic interpretation on brain cooling strategies developed in animals by classifying and comparatively analyzing each typical biological brain cooling mechanism from the perspective of bio-heat transfer. Meanwhile, inspirations from such cooling in nature were proposed for developing advanced bionic engineering technologies especially with two focuses on therapeutic hypothermia and computer chip cooling areas. It is expected that many innovations can be achieved along this way to find out new cooling methodologies for a wide variety of industrial applications which will be highly efficient, energy saving, flexible or even intelligent.     

叶绿素b聚集体和它的能化态的性质

叶绿素b由单体聚合成多聚体后吸收光谱明显红移。叶绿素b聚集体膜在光下产生150 mV的光电位,停止照光后此电位消失速度比叶绿素a聚集体膜的慢。叶绿素b聚集体吸收光能后形成相当稳定的能化态,半生命期约几分钟。当聚集体解聚时所吸收的光能又以光的形式辐射出来。叶绿素b聚集体能化态的能量可快速而有效地传给叶绿素a聚集体,以叶绿素a的延迟发光形式释放出来。     

A Highly-Flexible and Breathable Photo-Thermo-Electric Membrane for Energy Harvesting

Photo-thermo-electric (PTE) technology is a simple but sustainable method that directly converts solar energy into electricity. However, the manufacturing of flexible and breathable PTE generators for practical applications, such as intelligent wearable and self-powered sensors, poses significant challenges due to the rigid thermoelectric materials and unbreathable substrates. Here, a highly-flexible and breathable photo-thermal-electric membrane (FB-PTEM) is developed by magnetron sputtering (MS) on a photo-thermal nanofiber membrane. A single unit of FB-PTEM produced an open-circuit voltage of 0.52 V under 1 sun (100 mW cm⁻²) and 0.2 V under LED illumination, making it suitable for all-weather use. The photo-thermal nanofiber membrane exhibited high photo-thermal conversion capacity of reaching 70 °C within 50 s under 1 sun irradiation. The FB-PTEM with a thickness of 0.35 mm achieved a self-temperature difference of 20.6 °C under 1 sun with the low thermal conductivity of the nanofiber membrane. Furthermore, it has a vapor permeability of 14.6 kg m⁻² d⁻¹ due to the inherent high porosity of the nanofiber membranes. The FB-PTEM demonstrates great potential for the development of highly flexible thermoelectric materials, as it encompasses various advantageous features such as self-temperature difference, lightweight design, high breathability, and all-weather suitability.     

Design and Mechanics Simulation of Bionic Lubrication System of Artificial Joints

We propose a new structure for artificial joints with a joint capsule which is designed to overcome the drawback of current prostheses that omit many functions of the lubricant and the joint capsule. The new structure is composed of three components： lubricant, artificial joint and artificial joint capsule. The lubricant sealed in the capsule can not only reduce the wear of the artificial joint but also prevents the wear particles leaking into the body. So unexpected reactions between the wear particles and body can be avoided completely. A three-dimensional （3-D） finite element analysis （FEA） model was created for a bionic knee joint with capsule. The stresses and their distribution in the artificial capsule were simulated with different thickness, loadings, and flexion angles. The results show that the maximum stress occurs in the area between the artificial joint and the capsule. The effects of capsule thickness and the angles of flexion on stress are discussed in detail.     

Technological Parameters and Design of Bionic Integrated Honeycomb Plates

We investigated an integrated manufacturing method to develop lightweight composite materials. To design the preparation process for the integrated honeycomb plates, the shear and compressive mechanical properties of the corresponding composite materials were also investigated. The results indicate that these composite materials, with two types of resins reinforced by short basalt fibers, exhibit obvious toughness, particularly in their compressive properties. The Epoxy Resin （ER） is denser and has better bonding at the fiber and matrix interface than the vinyl ester resin matrix. Therefore, the ER exhibits better shear and compressive strengths than the vinyl ester resin matrix, thereby providing a design technology of the preparation process of the integrated honeycomb plate. The matrix material of this plate is composed of an epoxy （E51 ）, a curing agent （593）, and a thinner （501） at a ratio of 10：3：1; short basalt fibers are added as a reinforcing material at a 30% volume fraction. By increasing the curing temperature and other experimental conditions, we obtained an expected integrated honeycomb plate. This integrated honeycomb plate possesses properties such as a high fiber content, good shear and compressive performance, and high proc- essing efficiency.     

易位子辅助膜蛋白插入热力学

易位子辅助膜蛋白插入内质网膜是膜蛋白质生物生成的关键过程。了解不同类分子插入生物膜的机制是预测溶质分子透膜速度的先决条件,这也是药物设计和药理学领域的关键因素。根据插入机制,可以设计插膜肽直接用于疾病治疗,或者作为载体有选择性地将药物靶向特定细胞。自从2004年第1个易位子通道蛋白（Sec）的晶体结构被解析后,近十几年来大量的实验和理论研究,都在致力于揭示Sec辅助膜蛋白插入过程的分子机制。本文总结了过去该领域的实验和分子动力学模拟研究进展,从热力学方面重点分析了造成膜蛋白插入自由能分子动力学模拟计算值,以及实验值间偏差的原因。其中,根据研究条件精确设置模拟参数、插入造成的膜变形对自由能计算有很大的影响;核糖体为新生肽插入到Sec通道过程提供了能量,核糖体与Sec的结合影响Sec侧门的开放程度和Sec通道的结构,从而降低膜插入自由能。Sec辅助膜蛋白插入是一个极其复杂的过程,但整个过程仍然符合热力学和动力学的基本原理,尽管疏水性是Sec辅助膜蛋白质插入的关键性因素,但也不能忽略动力学因素的影响。     

The Mechanism of Drag Reduction around Bodies of Revolution Using Bionic Non-Smooth Surfaces

Bionic non-smooth surfaces （BNSS） can reduce drag. Much attention has been paid to the mechanism of shear stress reduction by riblets. The mechanism of pressure force reduction by bionic non-smooth surfaces on bodies of revolution has not been well investigated. In this work CFD simulation has revealed the mechanism of drag reduction by BNSS, which may work in three ways. First, BNSS on bodies of revolution may lower the surface velocity of the medium, which prevents the sudden speed up of air on the cross section. So the bottom pressure of the model would not be disturbed sharply, resulting in less energy loss and drag reduction. Second, the magnitude of vorticity induced by the bionic model becomes smaller because, due to the sculpturing, the growth of tiny air bubbles is avoided. Thus the large moment of inertia induced by large air bubble is reduced. The reduction of the vorticity could reduce the dissipation of the eddy. So the pressure force could also be reduced. Third, the thickness of the momentum layer on the model becomes less which, according to the relationship between the drag coefficient and the momentum thickness, reduces drag.