生物的性变及控制

动物一般是雌雄异体,性别终生不变。可是在复杂的动物界,也有少数动物的性别会发生改变。刚出生的牡蛎全部是雄性,并且幼年期就开始排精,充当"父亲"的角色。但是一年之后的雄性牡蛎全部转为雌性,形成卵巢,排出卵细胞,精巢消失,又成了名副其实的母体。生活在阿拉伯海的红鲷鱼,它们由一条雄鱼和一群雌鱼组成一个"一夫多妻"的"家"。如果这"一家之长"的雄鱼不幸丧生,那么,其中一条身体健壮的雌鱼就会鳍变长,身材长粗、卵巢消失,精囊出现,变成一条雄性的红鲷鱼,从而又恢复了一个和谐的"家",继续生儿育女。

ELASTIC DEFORMATION ANALYSIS OF MULTILA YERED STRANDS

This paper describes a general model for the mechanical behavior studying of general wire rope strand. An exact solution of the deformation characteristics was given when the strands is under tensile and torsional loads. The theoretical results are useful in evaluating the extensional and torsional moduli of rigidity for the strands. Finally, a simple design criterion is establised for the nonrotating ropes.

Novel measurement scheme of peak separation of side-hole fiber grating

There are two peaks of different polarizations in the reflection spectrum of the side-hole fiber grating and their separation interval has a linear variation along with the pressure changing while it is insensitive to the temperature.We have proposed a novel measurement scheme based on polarization detection.The detection of peak separation is achieved by measuring the two peaks’ center wavelengths separately with all polarization maintaining fiber system.The side-hole fiber grating pressure sensing within the range of 0～3.5 MPa is realized successfully with the new scheme.

Simple shear endochronic equations for finite plastic deformation

The endochronic equations proposed by Valanis (1980) were extended to a finite deformation range. Jaumanns rate, Fus rate and Wus rate were incorporated into the endochronic equations to analyze simple shear finite deformation. Incremental equations and numerical solutions are deduced for three endochronic objective models. The results show that an oscillatory shear stress response to a monotonically increasing shear strain occurs when the Jaumanns rate objective model is employed for endochronic materials. The oscillatory response is dependent on the adopted objective rate. Compared with the Jaumanns rate, the Fus rate and the Wus rate satisfy the restrictions to elastic-plastic constitutive relations and are in agreement with the experimental results.

The Effect of Signs Design of Wayfinding to Elders in Hospital： Take National Taiwan University College of Medicine for Example

Taiwan had officially entered aging society in 1993, and meantime the birthrate reaches its lowest point again and again. The constitution of population dramatically turns into an elder and low-birthrate society. Therefore, the ratio of elders living along is increasing yearly. When the elders need to deal the illness and go to hospital along, decays come from degeneration might have affect on their activity in accessible environment in hospital. Signs is a vital tool for delivering and communicating information in the road sign system. Whether the elders can identify the signs in hospital clearly becomes an important issue in the current research. To understand the affect of signs design in hospital to elders, the research reviewed and gained insight of degeneration in both physical and psychological of elders and the proper principal of signs design for elders. The research surveys in Taipei City, which has densest medical center, and mainly focus on National Taiwan University College of Medicine, which has hundred years of history （founded in 1895）. The research conducts field survey in both old and new buildings of National Taiwan University College of Medicine in August, 2015. The survey includes five types of signs design： Public Facilities, Prohibition, Safety, Warning, and Commercial Facilities. The result from article review indicates the most salient psychological degenerations includes the change in cognitive function, decay of memory, and deceleration of information processing; physical degenerations includes the decay of vision. As a result, the following properties should be taken into consideration when designing sings for elders： （1） The proper ratio of graphic and text. （2） Avoid using colors or matches difficult to identify by elders, like purple, blue, and green. （3） Take the visibility, legibility, identity, attention, and memory into consideration, there should be 70% differentiation in contrast between text of sign and background. （4） Avoid using multi-meaning graphic, keep the design simple. The result from the survey of National Yaiwan University College of Medicine indicates： （1） Using mainly on graphic and text as subsidiary, part of the sign design using both Chinese and English, and make sure the appropriateness of ratio between graphic and text. Use more of sans-serif font, which has better legibility. （2） Match the color mainly as yellow background with black graphic, blue background with white graphic, white background with black graphic, white background with blue graphic, a strong contrast between background and graphic on brightness and chroma matches the principle of visibility, legibility, and identity. （3） Simplify the signs design may safeguard its visibility. When elder need to handle illness comes from degeneration alone and go to large and complex hospitals frequently, the decay of their mental and physical might have a huge negative affect. Therefore, the signs design in hospital should understand their properties and design signs that match their requirement, to safeguard their live independency.

Evolution of Damage on Historical Heritage Buildings in Presence of Catastrophic Events and Aggressive Natural Phenomena

The feasibility analysis of projects for the preservation of the historical heritage buildings is an important problem concerning the evaluation of ＂the total cost of intervention＂, which includes all the future damage costs. The total cost of intervention represents a suitable measure of the expected deterioration risk and its evolution obviously depends on the damage process which buildings are subjected to. That damage phenomena affecting masonry buildings pleased into an aggressive environment are suitably modelled by renewal processes： this happens both in the case of catastrophic events, or in the case of the so-called ＂natural aging＂, in which damage comes off gradually in time. In the hypothesis ofa Markovian renewal process （Mrp） describing the damage process, the total cost of all the future damage is evaluated taking into account both the damage aspects： damages due to catastrophic aspects and damages due to aggressive environment, supposing different maintenance and/or rehabilitation scenarios. A semi-Markov process （s-Mp） is defined to model the damage rehabilitation history of buildings in presence of seismic events, natural ageing and rehabilitation strategies. The expected rewards connected to the process are defined; they represent a significant measure of the risk.

Swallowtail model for predicting the global bifurcation behavior of CO oxidation reactions

Catalytic CO oxidation on platinum group metals exhibits nonlinear phenomena such as hysteresis and bifurcation.Elucidation of the nonlinear mechanisms is important for catalyst design and control of reaction routes.Previous studies have offered initial insights into the local bifurcation behavior of CO oxidation.However,since the bifurcation behavior of CO oxidation is determined by multiple parameters such as temperature,total flux,and CO fraction,it is difficult to predict the global bifurcation behavior in the resulting high-dimensional parameter space.It is for this reason that the observed nonlinear phenomena reflect just the local bifurcation features of CO oxidation.In this paper,an elementary chemical law(topological invariance) concerning the bifurcation behavior of CO oxidation on platinum group metals such as Pd(111) is found from a topological perspective.Following the elementary law,we put forward a topological approach to model the critical criteria for the reaction hysteresis and bifurcation.The model may be applied to predict the global bifurcation behavior of CO oxidation in the high-dimensional parameter space.The topological approach and the model results may be useful as a guide in thinking about the complex reaction mechanism,designing reaction routes,and actively controlling the bifurcation behavior of the CO oxidation reaction.

Photosensitivity in Ce/Sm-decorated Keggin polyoxomolybdates:an interesting photoinduced coloration phenomenon of mixed- metal clusters involving energy transfer from rare-earth fluorescence

Ce/Sm ions are covalently grafted to a Keggin polyoxomolybdate cluster[PMo12O40]3-to yield interesting fluorescent-photodarkening molecular systems.Their photoresponce processes are observed to be activated via energy transfer from luminescent fragments to photocoloration components.