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排序方式: 共有341条查询结果,搜索用时 15 毫秒
91.
92.
Heidi Thomas Dominik L. Pastoetter Max Gmelch Tim Achenbach Annika Schlögl Marine Louis Xinliang Feng Sebastian Reineke 《Advanced materials (Deerfield Beach, Fla.)》2020,32(19):2000880
In recent years, there has been a growing interest in purely organic materials showing ultralong room-temperature phosphorescence with lifetimes in the range of seconds. Still, the longest known phosphorescence lifetimes are only achieved with crystalline systems so far. Here, a rational design of a completely new family of halogen-free organic luminescent derivatives in amorphous matrices, displaying both conventional fluorescence and phosphorescence is reported. Hydrogen bonding between the newly developed emitters and an ethylene-vinyl alcohol copolymer (Exceval) matrix, which efficiently suppresses vibrational dissipation, enables bright long-lived phosphorescence with lifetimes up to 2.6 s at around 480 nm. The importance of the chosen matrix is shown as well as the implementation in an organic programmable luminescent tag. 相似文献
93.
Influence of the length of the internal sleeve valve on the release of powdery substances from the closures of valved bags for dangerous goods 下载免费PDF全文
Eva Schlick‐Hasper Mario Eiben Björn Drousch Annika Heinrich Thomas Goedecke Matthias Kraume 《Packaging Technology and Science》2018,31(8):532-544
In practice, checks on dangerous goods transports often detect leaks of powdered dangerous goods from valved bags. In this work, the influence factors of a sudden release of powdery substances from the valves of valved bags were investigated. Drop tests were performed on paper bags of UN design type 5M2 with internal sleeve valve using 2 different powdery substances (Esplas H130 and zinc oxide “Rotsiegel”). The internal sleeve valves of all test samples were not sift‐proof with respect to both filling substances. For almost all test samples, the Esplas H130 powder already leaked out of pasted joints during manual filling. This is a contradiction to the requirement in UN 6.1.4.18.1, according to which closures and joints of paper bags 5M2 should be sift‐proof. In the drop tests, longer valve lengths had a greater sealing effect for both filling substances (for filling degrees of at least 95% and for test samples which had already been mechanically loaded). As an extreme example, at the drop height of 1.20 m and a filling degree of 100%, the released amount of zinc oxide powder from a 10‐cm‐long valve was about 16 times higher than from a valve length of 12.5 cm. The valve length is therefore a safety‐relevant parameter and should be specified by the manufacturer. To ensure that only filling goods with similar physical properties in comparison with the test substance are used for valved bags, the user must be informed of the particle size of the test substance. 相似文献
94.
Ion Petre Andrzej Mizera Claire L. Hyder Annika Meinander Andrey Mikhailov Richard I. Morimoto Lea Sistonen John E. Eriksson Ralph-Johan Back 《Natural computing》2011,10(1):595-612
The heat shock response is a primordial defense mechanism against cell stress and protein misfolding. It proceeds with the
minimum number of mechanisms that any regulatory network must include, a stress-induced activation and a feedback regulation,
and can thus be regarded as the archetype for a cellular regulatory process. We propose here a simple mechanistic model for
the eukaryotic heat shock response, including its mathematical validation. Based on numerical predictions of the model and
on its sensitivity analysis, we minimize the model by identifying the reactions with marginal contribution to the heat shock
response. As the heat shock response is a very basic and conserved regulatory network, our analysis of the network provides
a useful foundation for modeling strategies of more complex cellular processes. 相似文献
95.
A non-linear programming method is developed for optimization of inelastic cylindrical shells with internal ring supports.
The shells under consideration are subjected to internal pressure loading and axial tension. The material of shells is a composite
which is considered as an anisotropic inelastic material obeying the yield condition suggested by Lance and Robinson. Taking
geometrical non/linearity of the structure into account optimal locations of internal ring supports are determined so that
the cost function attains its minimum value. A particular problem of minimization of the mean deflection of the shell with
weakened singular cross sections is treated in a greater detail. 相似文献
96.
Larsson AF 《Applied ergonomics》2012,43(3):501-506
Automation, in terms of systems such as adaptive/active cruise control (ACC) or collision warning systems, is increasingly becoming a part of everyday driving. These systems are not perfect though, and the driver has to be prepared to reclaim control in situations very similar to those the system easily handles by itself. This paper uses a questionnaire answered by 130 ACC users to discuss future research needs in the area of driver assistance systems. Results show that the longer drivers use their systems, the more aware of its limitations they become. Moreover, the drivers report that ACC forces them to take control intermittently. According to theory, this might actually be better than a more perfect system, as it provides preparation for unexpected situations requiring the driver to reclaim control. 相似文献
97.
Paukner Annika; Anderson James R.; Donaldson David I.; Ferrari Pier F. 《Canadian Metallurgical Quarterly》2007,33(2):139
Two macaques (Macaca nemestrina) were trained to perform 3 self-directed behaviors on signal and to repeat behaviors after a 'repeat' signal. The cognitive processes underlying the monkeys' repeat performance were evaluated via multiple repetitions of the repeat signal, extended delay periods between target behavior and repeat signal, and by transferring the repeat signal to novel behaviors. The monkeys seemed to use representations of their own past behaviors as a basis for repetition performance, but they mostly failed to correctly repeat target behaviors after extended delays and during transfer tasks. Implications for episodic memory abilities are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
98.
The perception of texture has been correlated to the microstructure of particulate whey protein gels. A full, two-level, factorial experimental design was used in which the processing conditions, pH, heating rate and addition of salt were used as design factors. The texture of the gels was analysed by a sensory panel, and the microstructure was analysed by light and electron microscopy. The microstructure was quantified by using different types of image analysis.
In this study of particulate whey protein gels, the test principles of analysing texture were divided into two groups: destructive tests and non-destructive tests. The microstructural parameters can also be divided into two groups: overall network dimensions (pore size and particle size) and strand characteristics. The texture as measured with destructive methods was sensitive to overall network dimensions, whereas texture as measured with non-destructive methods was sensitive to the strand characteristics of particulate protein gels. 相似文献
99.
The empirical part of this study is based on a survey of 600 Swedish households and a number of interviews where questions about residential energy behaviour and possible policy instruments for change were raised. The study provides insight into current behavioural patterns and gives a bottom-up perspective on the realistic perspective potentials for change and ways to achieve them. Residential energy use accounts for a fifth of the total in Northern nations and patterns of behaviour may influence levels of energy use to the same extent as choice of appliances. The study revealed those behavioural patterns that are efficient and those that need to be improved for energy conservation. Several policy instruments for change were identified in the study and they include combinations of information, economic measures, administrative measures and more user friendly technology as well as equipment with sufficient esthetic quality. Policy instruments that have fostered energy efficient behaviour in Sweden include the massive information campaigns during the oil crises in the 1970s as well as energy labelling of appliances. Still, many households are “energy-unaware” and several energy efficient behaviours are motivated not by energy conservation concern but of a perceived lack of time. This shows that it is important to have a broad perspective in energy conservation, to evaluate trends and to use policy instruments timely to support or discourage them. 相似文献
100.
Fridell Erik Amberntsson Annika Olsson Louise Grant Ann W. Skoglundh Magnus 《Topics in Catalysis》2004,27(1-4):143-155
A review covering some of the key catalytic transformations of the major monoterpene feedstocks. Monoterpenes are key ingredients in the flavor and fragrance industry, with α- and β-pinene (obtained from turpentine) being some of the most important. The review focuses on the hydrocarbons; pinene, limonene, carene, and the interconversion of the monooxygenates; geraniol/nerol, citronellol, citral, and citronellal. The major areas covered are catalytic hydrogenation/hydrogenolysis, dehydrogenation, rearrangement/isomerization/aromatization, reactions with carbon monoxide, epoxidation, and the addition of alcohols and acids. 相似文献