生命体能量代谢过程中的电子传递与光合作用中电子传递反应的化学模拟的ESR研究

本文采用电子自旋共振ESR方法，结合运用自旋捕捉技术（Spin Trapping-ESR）和时间分辨手段(TRESR)，针对某些与生命能量代谢体系电子传递及其化学模拟反应的研究相关的几个重要问题(包括高等植物光系统II颗粒内超氧阴离子自由基(O2-)的产生机制、光合作用模型体系电子传递和跨膜电子传递反应动力学、传统中药有效成分提取物抗氧化分子机理与构效关系），从分子设计、实验方法、分子结构理论、反应机理与动力学分析等几个角度进行了较为系统的探索性研究，并获得以下几点新颖的研究成果： 1．光系统II颗粒内光抑制过程中O2-生成的分子机制 (1)．首先，发展了新Spin Trapping-ESR技术，研制一系列性能优良的新型磷酰基取代的吡咯啉类活性氧自旋捕捉剂，并通过对比研究其捕捉性能，证明磷酰基取代的吡咯啉类捕捉剂比常用的DMPO捕捉剂的捕捉能力强、速度快，自由基加合物稳定性高，适合于光系统II体系中活性氧的研究。 (2)．在PSII颗粒的光抑制过程中成功地检测到了O2-，并探讨了影响O2-产生的诸多因素。包括氧分子的浓度、1O2增强剂与淬灭剂、pH值效应、电子传递链阻断剂的影响。首次提出了O2-生成的分子机制：PSII颗粒中产生的O2-是光系统II中反应中心产生的1O2与次级电子受体QA形成的质子化半醌自由基反应的产物。此外，设计了一套化学模拟体系，进一步证明了02-的生成的分子机制。 2. 中国传统性中药的酚类提取物抗氧化剂的抗氧化分子机理与构效关系研究 用理论计算与实验结合的手段，研究了酚类抗氧化剂与02的反应。探讨了酚类抗氧化物的分子结构与其抗氧化活性的构效关系，为评价抗氧化剂的抗氧化能力提供了一定的依据。 3．有关光合作用模型体系电子传递和跨膜电子传递反应动力学的探索性基础研究 (1)．对原有的电子自旋共振谱仪进行改造，自行设计并研制一套时间分辨ESR装置，时间分辨率达到准微秒级。 (2)．利用时间分辨ESR装置，对C60及其环加成衍生物分子间和分子内光诱导电子转移反应的自由基复合过程动力学进行了研究，从分子结构角度分析了影响电荷分离态稳定性的因素。 (3)．初步探讨了TPP／DODAC与HA／DODAC两种单层囊泡间的光诱导电子转移反应，获得了长寿命的电荷分离态，为光合作用模拟提供有价值的模型。 (4)．通过对比研究mes-卟啉Ⅱ／苯醌／CH。OH的化学诱导动态核自旋态极化( CIDNP)和ESR波谱，提出一个激发态苯醌与质子给体间的光诱导氢转移自由基反应新机理。

用于奇异核探测的光电脉冲束流调制器

本实用新型涉及一种用于奇异核探测的光电脉冲束流调制器，含有步进电机、靶和探测器等，在靶与探测器之间放置有转盘，在转盘的径向对称位置间隔对应设有宽缝和窄缝，在对应窄缝位置的转盘两侧分别设有光源和光电传感器，宽缝与靶和探测器的位置对应；光电传感器与束流调制脉冲信号发生电路相联；该装置可探测核寿命短于３０毫秒的核衰变、探测收集效率比传统的氦喷嘴技术提高１个数量级以上；核寿命越短，其探测效率增加的效应越显著。

Some socio-economic aspects of the fishermen of twin pronged floodplain wetlands in West Bengal

A socio-economic investigation was carried out in two fishermen cooperative societies namely Purba Helatala Fishermen Co-operative Society (E-1), Barhal Fishermen Co-operative Society (E-2), under Maldah district, West Bengal to which the beels (flood plains) under study belong. A total of 132 member fishermen, which constituted the sample, were personally interviewed. The age group of the fishermen of the sample in E-1 varied between 20 and 66 years whereas in E-2 it was 22 and 61 years. All the members of the sample belonged to Scheduled Caste (SC) community. The primary occupation of all the respondents of both the beels was observed to be fishing (100%). Maximum number of illiterate respondents was observed to 56% in E-2 and 35% in E-1. It has been observed that as many as 38.3% of fishermen were having fishing experience which ranging from 16 to 20 years in E-1 whereas it was 6 - 10 years (36.1%) in E-2. Maximum number of fishermen lived in thatched houses (41.66%) in E-1 whereas in E-2 most of them lived in houses made of corrugated tin/tile shed (41.66%). As many as 41.55% of E-1 and 30.55% of E-2 used dug-out canoes for their fishing. Maximum number of fishermen used cast net with individualistic approach (100%) followed by Gill net (E-1:41.56% and E-2:55.55%). Most of the fishermen of the sample participated in fishing activities for 241 to 270 days (41.66%) in E-2 whereas it was 211 to 240 days (33.33 %) in E-1 in a year. During fishing season as many as 40.0% of the respondents of E-1 earned on an average Rs. 801.00 to Rs. 900.00 per month whereas it was Rs. 901.00 to Rs.1,000.00 (43.05%) in case of E-2. A section of fishermen of the sample borrowed money often (51.6%) E-1 whereas it was most often (27.27%) of E-2. The respondents of E-2 made regular repayment of the loan to the maximum extent (79.48%) whereas it was 57.44% in E-1. Higher fish production vis-a-vis higher income for the fishermen was observed in the beel (E2) having close characteristic.

Central representation of dynamics when manipulating handheld objects.

To explore the neural mechanisms related to representation of the manipulation dynamics of objects, we performed whole-brain fMRI while subjects balanced an object in stable and highly unstable states and while they balanced a rigid object and a flexible object in the same unstable state, in all cases without vision. In this way, we varied the extent to which an internal model of the manipulation dynamics was required in the moment-to-moment control of the object's orientation. We hypothesized that activity in primary motor cortex would reflect the amount of muscle activation under each condition. In contrast, we hypothesized that cerebellar activity would be more strongly related to the stability and complexity of the manipulation dynamics because the cerebellum has been implicated in internal model-based control. As hypothesized, the dynamics-related activation of the cerebellum was quite different from that of the primary motor cortex. Changes in cerebellar activity were much greater than would have been predicted from differences in muscle activation when the stability and complexity of the manipulation dynamics were contrasted. On the other hand, the activity of the primary motor cortex more closely resembled the mean motor output necessary to execute the task. We also discovered a small region near the anterior edge of the ipsilateral (right) inferior parietal lobule where activity was modulated with the complexity of the manipulation dynamics. We suggest that this is related to imagining the location and motion of an object with complex manipulation dynamics.

Coupling between elytra of some beetles: Mechanism, forces and effect of surface texture

Lightweight materials, structures and coupling mechanisms are very important for realizing advanced flight vehicles. Here, we obtained the geometric structures and morphologies of the elytra of beetles and ascertained its coupling zone by using the histological section technique and SEM. We set up a three-dimensional motion observing system to monitor the opening and closing behaviour of elytra in beetles and to determine the motion mechanism. We constructed a force measuring system to measure the coupling forces between elytra. The results show that elytra open and close by rotating about a single axle, where the coupling forces may be as high as 160 times its own bodyweight, the elytra coupling with the tenon and mortise mechanism, surface texture and opening angle between elytra heavily influence the coupling forces. These results may provide insights into the design mechanism and structure for future vehicles of flight.

样点法在森林鸟类调查中的运用

下载PDF阅读器样点法由于具有易于实施、更易做到随机化或系统化以及适合于复杂及斑块化生境等优点,已成为目前使用最为广泛的森林鸟类调查方法.本文在介绍样点法的假设条件、类型和影响鸟类调查准确性因素的基础上,重点介绍了样点法在调查森林鸟类需要考虑的样本大小、样点布设、调查时间、每点的停留时间和调查周期等.同时也分析了样点法的不足,并提出样点法与网捕法结合是提高调查结果准确性的有效途径.

Task-dependent coordination of rapid bimanual motor responses.

Optimal feedback control postulates that feedback responses depend on the task relevance of any perturbations. We test this prediction in a bimanual task, conceptually similar to balancing a laden tray, in which each hand could be perturbed up or down. Single-limb mechanical perturbations produced long-latency reflex responses ("rapid motor responses") in the contralateral limb of appropriate direction and magnitude to maintain the tray horizontal. During bimanual perturbations, rapid motor responses modulated appropriately depending on the extent to which perturbations affected tray orientation. Specifically, despite receiving the same mechanical perturbation causing muscle stretch, the strongest responses were produced when the contralateral arm was perturbed in the opposite direction (large tray tilt) rather than in the same direction or not perturbed at all. Rapid responses from shortening extensors depended on a nonlinear summation of the sensory information from the arms, with the response to a bimanual same-direction perturbation (orientation maintained) being less than the sum of the component unimanual perturbations (task relevant). We conclude that task-dependent tuning of reflexes can be modulated online within a single trial based on a complex interaction across the arms.

Vehicle trajectory linearisation to enable efficient optimisation of the constant speed racing line

A driver model is presented capable of optimising the trajectory of a simple dynamic nonlinear vehicle, at constant forward speed, so that progression along a predefined track is maximised as a function of time. In doing so, the model is able to continually operate a vehicle at its lateral-handling limit, maximising vehicle performance. The technique used forms a part of the solution to the motor racing objective of minimising lap time. A new approach of formulating the minimum lap time problem is motivated by the need for a more computationally efficient and robust tool-set for understanding on-the-limit driving behaviour. This has been achieved through set point-dependent linearisation of the vehicle model and coupling the vehicle-track system using an intrinsic coordinate description. Through this, the geometric vehicle trajectory had been linearised relative to the track reference, leading to new path optimisation algorithm which can be formed as a computationally efficient convex quadratic programming problem. © 2012 Copyright Taylor and Francis Group, LLC.

What kind of friction model is needed to predict brake squeal?

Predictive models of friction-induced vibration have proved elusive despite decades of research. There are many mechanisms that can cause brake squeal; friction coupled systems can be highly sensitive to small perturbations; and the dynamic properties of friction at the contact zone seem to be poorly understood. This paper describes experimental and theoretical work aimed at identifying the key ingredients of a predictive model. A large-scale experiment was carried out to identify squeal initiations using a pin-on-disc test rig: approximately 30,000 squeal initiations were recorded, covering a very wide range of frequencies. The theoretical model allows for completely general linear systems coupled at a single sliding point by friction: squeal is predicted using a linearised stability analysis. Results will be presented that show that almost all observed squeal events can be predicted within this model framework, but that some subsets require innovative friction modelling: predictions are highly dependent on the particular choice of friction model and its associated parameters. Copyright © 2012 by ASME.

Wave dispersion and power flow analysis of an infinite aerofoil-shaped beam

Classic flutter analysis models an aerofoil as a two degree-of-freedom rigid body supported by linear and torsional springs, which represent the bending and torsional stiffness of the aerofoil section. In this classic flutter model, no energy transfer or dissipation can occur in the span-wise direction of the aerofoil section. However, as the aspect ratio of an aerofoil section increases, this span-wise energy transfer - in the form of travelling waves - becomes important to the overall system dynamics. This paper extends the classic flutter model to include travelling waves in the span-wise direction. Namely, wave dispersion and power flow analysis of an infinite, aerofoil-shaped beam, subject to bending, torsion, tension and a constant wind excitation, is used to investigate the overall system stability. Examples of potential applications for these high aspect ratio aerofoil sections include high-altitude balloon tethers, towed cables, offshore risers and mooring lines.