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Sample geometry effects on mechanical strengths of gold micro-cantilevers are evaluated by a micro-bending test. Six micro-cantilevers with the same length of 50 μm are prepared, and the width and the thickness are varied to examine individual effects on the yield stress. The yield stress increases from 428 to 519 MPa when the thickness decreases from 11.1 to 6.0 μm. No obvious dependency is observed when varying the width. The results reveal that the thickness and the width each has a different influence on the yield stresses of micro-cantilevers evaluated by the bending test, which is the sample geometry effect.
We report fourteen and twenty-eight protocluster candidates at z = 5.7 and 6.6 over 14 and 19 deg2 areas, respectively, selected from 2,230 Lyα emitters (LAEs) photometrically identified with Subaru/Hyper Suprime-Cam (HSC) deep images. Six out of the 42 protocluster candidates include at least 1 spectroscopically confirmed LAEs at redshifts up to z = 6.574. By the comparisons with the cosmological Lyα radiative transfer (RT) model reproducing LAEs with the reionization effects, we find that more than a half of these protocluster candidates might be progenitors of the present-day clusters with a mass of ≳ 1014M⊙. We also investigate the correlation between LAE overdensity and Lya rest-frame equivalent width (EW), because the cosmological Lyα RT model suggests that a slope of EW-overdensity relation is steepened towards the epoch of cosmic reionization (EoR), due to the existence of the ionized bubbles around galaxy overdensities easing the escape of Lyα emission from the partly neutral intergalactic medium. The available HSC data suggest that the slope of the EW-overdensity correlation does not evolve from the post-reionization epoch z = 5.7 to the EoR z = 6.6 beyond the moderately large statistical errors.
The effects of TiCl4 post-treatment on the physicochemical properties of porous TiO2 (pTiO2) layers fabricated at 300 °C and 400 °C (denoted as pTiO2(300) and pTiO2(400), respectively) in CH3NH3PbI3 perovskite photovoltaic cells were investigated. Water contents (physisorbed water and water derived from surface hydroxyl groups) of pTiO2(300) and pTiO2(400) before and after TiCl4 post-treatment were measured by using temperature desorption spectroscopy (TDS). Moreover, structural analysis of the CH3NH3PbI3 perovskite part was performed by X-ray diffraction (XRD). In the case of pTiO2(300), the content of water was increased by the TiCl4 post-treatment due to the removal of residual organic compounds that existed before the treatment. It then caused a change in the surface activity of pTiO2(300) and enhancement of solar cell performance and photocurrent density, though suppression of CH3NH3PbI3 perovskite formation occurred. In comparison, contents of water were decreased for pTiO2(400), leading to enhancement of the conversion of PbI2 to CH3NH3PbI3 perovskite. As a result, there were significant increases in short circuit current density (Jscs) and PCEs. The results showed that TiCl4 post-treatment is an effective approach to prepare high-performance CH3NH3PbI3 perovskite solar cells without heat treatment at a very high temperature.
In this study, the initial AlN layer and the vertical-direction breakdown voltage (VDBV) of AlGaN/GaN high-electron-mobility transistors (HEMTs) were characterized. Prior to the formation of the interface between the AlN layer and the Si substrate, only trimethylaluminum (TMA) was introduced without ammonia to control the crystal quality of initial AlN layer (TMA preflow). HEMT structures were simultaneously grown on identical AlN layers on Si substrates (AlN/Si templates) grown using different TMA preflow temperatures. The density of screw- or mixed-type dislocations in the initial AlN layer decreased as the TMA preflow temperature increased. Further, the VDBV of the HEMT structure increased as the TMA preflow temperature increased. It is supposed that the screw- or mixed-type dislocations are the possible source of the vertical leakage current in the HEMT structures. The improvement in the crystal quality of the initial AlN layer affects the increase in the VDBV of the AlGaN/GaN HEMTs on Si substrates.
To control an input energy for a load, an impedance control with a gap distance of an electron beam diode was studied using an intense pulsed-power generator. The output current of the pulsed-power generator as a function of the gap distance of electron beam diode was measured. It indicated that the behaviors of the experimentally obtained peak current and the theoretically obtained space-charge limited current were found to decrease with an increase in the gap distance. The input energy for the load was estimated from the output current, which decreased with an increase in the gap distance. It also revealed the space-charge limited current suppresses the input energy for the load with a decade.
At the beginning of the Victorian era, London Zoo thrived as the premier resort of the metropolis. It attracted myriads of people from different walks of life, from urban promenaders to gentleman menagerists, from Indian shipbuilders to Persian princes, and included such leading figures of the day as Charles Darwin. This examination of the Zoo places it within the broader context of nineteenth-century Britain, looking at the politics of culture in the new public domain of museums and galleries, the professionalisation and popularisation of science in a new, consumer society, and how the growing urban population regarded the animals on display. Dr Takashi Ito teaches at Kanazawa Gakuin University, Japan.
‘The characteristic of the English populace – perhaps we ought to say people, for it extends to the middle classes – is their propensity to mischief. The people of most other countries may safely be admitted into parks, gardens, and public buildings, and galleries of pictures and statues; but in England it is necessary to exclude them, as much as possible, from all such places … This disgraceful part of the English character … can neither be soon nor easily corrected; but anything tends to correct it that contributes to give the people a taste for intellectual pleasures.’
In principle, the London Zoo was open only to Fellows of the Zoological Society, their families and friends. This policy remained unchanged during the first two decades of the zoo's history. In practice, however, the zoo was accessible even to those who were not acquainted with Fellows. The society carefully regulated its complex admission system, but the illegal entry of those described by the society as ‘improper characters’ was common. There was also a continuing tension between the society's attempts to expel strangers and the growing demand for open access to the zoo. As a result, the question of access arose not only with regard to the London Zoo, but also other public institutions involved in the arts and sciences.
The zoo and science interacted with each other in various ways. The zoo was a platform for rising zoologists who sought to authenticate their scientific activities, but it also problematised relationships between science and its public by raising the question of accessibility. It has also been argued that the London Zoo embodied the boundary between the separate scientific spheres: as a site of ‘recreational science’, it formed a bridge between the scientific community and the non-specialist public, and provided financial and material resources for ‘legitimate science’. Yet this book has not explored exactly what kind of science was being engaged in at the London Zoo. This chapter thus contemplates the question of science by tracing David Mitchell's attempt to reconfigure the zoo as an institute of ‘acclimatisation’ – a new form of science that he believed would employ the knowledge and materials available at the zoo.
The validity of the concept of ‘imperial zoo’ can also be tested through a study of acclimatisation. It can be seen as a particular form of the science/empire symbiosis that demonstrated the dynamic interactions between home institutions and the colonial field. The trajectory of acclimatisation at the London Zoo, however, does not necessarily underline this interpretation. Certainly, it appears to be a manifestation of the British imperial intervention in colonial nature. It was indeed an ambitious attempt to regenerate the zoo as a centre of ‘zoological empire’, which would use animals as colonial resources on an unprecedentedly large scale.
Of all the scientific institutions in Britain the Zoological Society had the largest funds. Charles Babbage remarked in his Reflections on the decline of science in England (1830) that the enormity of the society's income was ‘a frightful consideration’. The society's affluence placed it in a different category from other scientific institutions and also drew public attention to its spending patterns. Whereas most scientific institutions were funded by voluntary subscriptions, the Zoological Society had an additional source of income: receipts from admission to the London Zoo. The potential was clearly identified by William Swainson, naturalist and external critic of the society, who explained its two principal aims in his A preliminary discourse on the study of natural history (1834): promotion of ‘legitimate science’ and provision of ‘popular recreation’. He hoped that the society would unite these spheres:
Where there are ample funds, as in the present case, a judicious management may unite, in equal proportions, popular recreation with the encouragement of legitimate science; for the attraction of the former would raise funds for paying the latter, and thus the highest objects might be combined with those that were more ornamental than useful.
His proposals questioned the public rationale of the Zoological Society, but their importance hardly registered at a time when the society had such confidence in the popularity of the zoo.
Charles Darwin loved to visit the London Zoo. He wrote to his sister Caroline in April 1831 that ‘what I liked most in all London is the Zoolog[ical] Gardens: on a hot day when the beasts look happy and the people gay it is most delightful’. In March 1838, after returning from his voyage on the Beagle, Darwin visited the zoo again. He was fortunate enough to see the rhinoceros emerging from her house and galloping in the enclosure ‘surprisingly quickly, like a huge cow’. The elephant in the next yard responded to his neighbour and began ‘trotting himself’ and ‘squealing & braying like a half dozen broken trumpets’. The most exciting attraction of the year was, however, Jenny, the first orangutan exhibited to the public at the London Zoo. Darwin observed her intelligence and emotional expression and compared her to a human child:
I saw also the Ourang-outang in great perfection: the keeper showed her an apple, but did not give it her, whereupon she threw herself on her back, kicked & cried, precisely like a naughty child. – She then looked very sulky & after two or three fits of passion, the keeper said, ‘Jenny if you will stop bawling & be a good girl, I will give you the apple’ – She certainly understood every word of this, & though like a child, she had great work to stop whining, she at last succeeded, & then got the apple, with which she jumped into an armchair & began eating it, with the most contented countenance imaginable.
The top celebrity in Paris in 1827 was not a human, but Zaraf the giraffe. For the first time since the sixteenth century a giraffe had been brought to Europe. On 30 June she was welcomed at the Muséum national d'histoire naturelle by thousands of Parisians, with great enthusiasm and curiosity. During the summer season, she was such a popular sensation that there was a new fashion boom: ‘every fashion turned to à la giraffe; and even the ladies wore dresses, and the men carried handkerchiefs, bearing the portrait of the animal’. A similar celebration was repeated nearly a decade later, this time in London, but on an even larger scale. Britain's first public exhibition of giraffes was hosted by the London Zoo and was the most frequently visited attraction of that year. The extraordinary popularity of the giraffes in both Paris and London could be partly explained by the rarity and extraordinary appearance of the animal, but it was also culturally constructed within a specific historical context.
By taking the example of the sensational exhibition of the giraffes, this chapter discusses two interrelated themes concerning the London Zoo. The first centres on the networks of animal collecting that enabled the Zoological Society to obtain its giraffes. The society took the advantage of the interconnected system of communication that operated across the British Empire. This system was not, however, identical to the animal collecting networks which often stretched way beyond the colonial field.
The path beyond the entrance gate to London's Zoological Gardens led to a long promenade lined with ornamental shrubs. At the far end bears were exhibited in a deep square pit, as depicted by George Scharf in one of his Six views of the Zoological Gardens (see cover illustration). Here a gentleman holds out a long stick with a bun stuck on the end, while the bear has climbed up a stout wooden pole. The spectators expect the bear to reach out and grab the bun. Contemporary commentators often described animal behaviour in analogy with human nature. In 1829 Toby the Russian black bear, who often had proffered food snatched away from him by two polar bears, was compared in one guidebook to ‘good-natured men who are mastered by those of rough natures’. This was a prime example of public interaction with nature presented as spectacle – a scene that sets the stage for this book on the London Zoo, which debates cultural politics, public science and the meaning of the animal world in nineteenth-century Britain. The scene at the bear pit spotlights the multifaceted nature of the zoo.
Although the development of zoos in nineteenth-century Europe and America has recently attracted scholarly attention, it is still necessary to clarify why the subject is important. A number of zoos today are challenged by those who criticise the caging of animals and are denounced as an institutional impediment to the protection of animal welfare.