Hysteresis‐Free 1D Network Mixed Halide‐Perovskite Semitransparent Solar Cells

The morphology of hybrid organic–inorganic perovskite films is known to strongly affect the performance of perovskite‐based solar cells. CH₃NH₃PbI_3‐xCl_x (MAPbI_3‐xCl_x) films have been previously fabricated with 100% surface coverage in glove boxes. In ambient air, fabrication generally relies on solvent engineering to obtain compact films. In contrast, this work explores the potential of altering the perovskites microstructure for solar cell engineering. This work starts with CH₃NH₃PbI_3‐xCl_x, films with grain morphology carefully controlled by varying the deposition speed during the spin‐coating process to fabricate efficient and partially transparent solar cells. Devices produced with a CH₃NH₃PbI_3‐xCl_x film and a compact thick top gold electrode reach a maximum efficiency of 10.2% but display a large photocurrent hysteresis. As it is demonstrated, the introduction of different concentrations of bromide in the precursor solution addresses the hysteresis issues and turns the film morphology into a partially transparent interconnected network of 1D microstructures. This approach leads to semitransparent solar cells with negligible hysteresis and efficiencies up to 7.2%, while allowing average transmission of 17% across the visible spectrum. This work demonstrates that the optimization of the perovskites composition can mitigate the hysteresis effects commonly attributed to the charge trapping within the perovskite film.     

Dielectric behavior of gelatine–glycosaminoglycans blends: An impedance analysis

The dielectric behavior of the gelatine–GAGs based blend systems has been studied to understand the dynamic behavior of the water at the protein–GAGs interfaces which are relevant for tissue engineering application. Impedance (Z) and phase have been measured as a function of frequencies from 0.01 Hz to 100 kHz. GAGs tunes the ionic charge drift which initiates polarization mechanisms through charge accumulation at structural interfaces and creates conduction currents. The admittance results showed that at high frequency, the conductivity increases with increasing GAGs concentration indicating changes in hydration shell of the gelatine by the GAGs.     

30平方米狂想曲

<正>大都市生活的快节奏,让私属空间也变得愈加紧凑,在这种情况下,家的设计便更加强调空间的利用与舒适性的平衡。最近完工的香港娱安楼住宅项目的改造,就是这种紧凑型户型设计的最佳案例。30平方米的空间,原     

淡蓝色的梦

如果做一个关于家居的梦,你的梦是什么颜色的?对S来说,她的梦想之家应该是一抹淡淡的蒂芙尼蓝,纯净优雅得不见半点点庸俗。显然,这不是一位甘于"将就"的业主。对于生活与居住,她讲究又有要求,即便是租住的房子,也要来一番彻头彻尾的翻新与变革,还专门聘请设计师帮助完成这个计划,壁纸的色彩,家具的风格,每一件她都精挑细选。与很多住在"房子里的人不同,她认为她是     

Integrated reconfiguration and age-based preventive maintenance decision making

The use of manufacturing system reconfiguration in conjunction with maintenance operations has not been previously reported in the literature. This research attempts to incorporate reconfiguration into Preventive Maintenance (PM) actions for improved system performance in terms of reduced total cost. This paper presents an Integrated Reconfiguration and Age-Based Maintenance (IRABM) policy and applies it to a parallel-serial manufacturing system. The expected total cost of implementing the IRABM policy is estimated and minimized through a simulation-based heuristic optimization procedure. Using this method, it is possible to systematically identify the conditions under which the integration of reconfiguration into maintenance is cost effective. In addition, numerical examples demonstrate that the manufacturing system could have a higher probability of fulfilling production requirements at a lower cost under the IRABM policy compared to the conventional age-based PM policy. The influences of the input parameters associated with reconfiguration, production, and reliability on the performance of IRABM policy also are studied.     

Perceived cultural importance and actual self-importance of values in cultural identification.

Cross-cultural psychologists assume that core cultural values define to a large extent what a culture is. Typically, core values are identified through an actual self-importance approach, in which core values are those that members of the culture as a group strongly endorse. In this article, the authors propose a perceived cultural importance approach to identifying core values, in which core values are values that members of the culture as a group generally believe to be important in the culture. In 5 studies, the authors examine the utility of the perceived cultural importance approach. Results consistently showed that, compared with values of high actual self-importance, values of high perceived cultural importance play a more important role in cultural identification. These findings have important implications for conceptualizing and measuring cultures. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

An analysis of hydrogen production from renewable electricity sources

Three aspects of producing hydrogen via renewable electricity sources are analyzed to determine the potential for solar and wind hydrogen production pathways: a renewable hydrogen resource assessment, a cost analysis of hydrogen production via electrolysis, and the annual energy requirements of producing hydrogen for refueling. The results indicate that ample resources exist to produce transportation fuel from wind and solar power. However, hydrogen prices are highly dependent on electricity prices. For renewables to produce hydrogen at $2 kg⁻¹, using electrolyzers available in 2004, electricity prices would have to be less than $0.01 kWh⁻¹. Additionally, energy requirements for hydrogen refueling stations are in excess of 20 GWh/year. It may be challenging for dedicated renewable systems at the filling station to meet such requirements. Therefore, while plentiful resources exist to provide clean electricity for the production of hydrogen for transportation fuel, challenges remain to identify optimum economic and technical configurations to provide renewable energy to distributed hydrogen refueling stations.     

Role of exercise training in the prevention and treatment of insulin resistance and non-insulin-dependent diabetes mellitus

Recent epidemiological studies indicate that individuals who maintain a physically active lifestyle are much less likely to develop impaired glucose tolerance and non-insulin-dependent diabetes mellitus (NIDDM). Moreover, it was found that the protective effect of physical activity was strongest for individuals at highest risk of developing NIDDM. Reducing the risk of insulin resistance and NIDDM by regularly performed exercise is also supported by several aging studies. It has been found that older individuals who vigorously train on a regular basis exhibit a greater glucose tolerance and a lower insulin response to a glucose challenge than sedentary individuals of similar age and weight. While the evidence is substantial that aerobic exercise training can reduce the risk of impaired glucose tolerance and NIDDM, the evidence that exercise training is beneficial in the treatment of NIDDM is not particularly strong. Many of the early studies investigating the effects of exercise training on NIDDM could not demonstrate improvements in fasting plasma glucose and insulin levels, or glucose tolerance. The adequacy of the training programmes in many of these studies, however, is questionable. More recent studies using prolonged, vigorous exercise-training protocols have produced more favourable results. There are several important adaptations to exercise training that may be beneficial in the prevention and treatment of insulin resistance, impaired glucose tolerance and NIDDM. An increase in abdominal fat accumulation and loss of muscle mass are highly associated with the development of insulin resistance. Exercise training results in preferential loss of fat from the central regions of the body and should therefore contribute significantly in preventing or alleviating insulin resistance due to its development. Likewise, exercise training can prevent muscle atrophy and stimulate muscle development. Several months of weight training has been found to significantly lower the insulin response to a glucose challenge without affecting glucose tolerance, and to increase the rate of glucose clearance during a euglycaemic clamp. Muscle glucose uptake is equal to the product of the arteriovenous glucose difference and the rate of glucose delivery or muscle blood flow. While it has been known for many years that insulin will accelerate blood glucose extraction by insulin-sensitive peripheral tissues, recent evidence suggests that it can also acutely vasodilate skeletal muscle and increase muscle blood flow in a dose-dependent manner. A reduced ability of insulin to stimulate muscle blood flow is a characteristic of insulin-resistant obese individuals and individuals with NIDDM. Exercise training, however, has been found to help alleviate this problem, and substantially improve the control of insulin over blood glucose. Improvements in insulin resistance and glucose tolerance with exercise training are highly related to an increased skeletal muscle insulin action. This increased insulin action is associated with an increase in the insulin-regulatable glucose transporters, GLUT4, and enzymes responsible for the phosphorylation, storage and oxidation of glucose. Changes in muscle morphology may also be important following training. With exercise training there is an increase in the conversion of fast twitch glycolytic IIb fibres to fast twitch oxidative IIa fibres, as well as an increase in capillary density. IIa fibres have a greater capillary density and are more insulin-sensitive and -responsive than IIb fibres. Evidence has been provided that morphological changes in muscle, particularly the capillary density of the muscle, are associated with changes in fasting insulin levels and glucose tolerance. Furthermore, significant correlations between glucose clearance, muscle capillary density and fibre type have been found in humans during a euglycaemic clamp. Exercise training may also improve control over hepatic glucose production by increasin     

怀旧的台湾味

走进香港九龙湾的这家垦丁茶室,立即被一股既时尚又怀旧的台湾风情包围。在蓝与白交织的想象空间中,周遭的船木与砖块让人犹如置身码头。淡淡的怀旧风,细细地诉