Diffusion and activation of n-type dopants in germanium

The diffusion and activation of $n$-type impurities (P and As) implanted into $p$-type Ge(100) substrates were examined under various dose and annealing conditions. The secondary ion mass spectrometry profiles of chemical concentrations indicated the existence of a sufficiently high number of impurities with increasing implanted doses. However, spreading resistance probe profiles of electrical concentrations showed electrical concentration saturation in spite of increasing doses and indicated poor activation of As relative to P in Ge. The relationships between the chemical and electrical concentrations of P in Ge and Si were calculated, taking into account the effect of incomplete ionization. The results indicated that the activation of P was almost the same in Ge and Si. The activation ratios obtained experimentally were similar to the calculated values, implying insufficient degeneration of Ge. The profiles of P in Ge substrates with and without damage generated by Ge ion implantation were compared, and it was clarified that the damage that may compensate the activated $n$-type dopants has no relationship with the activation of P in Ge.Comment: 6 pages, 4 figure

Effectiveness of a cool bed linen for thermal comfort and sleep quality in air-conditioned bedroom under hot-humid climate

Comfort temperature and sleep quality involving 20 participants were determined in two cases: Case A (arbitrary, controlled air-conditioner setting) and Case B (adjustment of 3 °C higher than the setting of Case A with cool bed linen). Data of indoor thermal comfort and electricity consumption were collected every night throughout the measurement period. Questionnaires on thermal comfort and sleep quality were distributed twice a night for a duration of three nights for each case; the first night was for respondents’ adaptation and the following two nights were for meas-urement. The sleep quality of the respondents was objectively measured using a commercially available activity tracker. Results found that most respondents were thermally comfortable in both cases, with 39% lower energy consumption reported for Case B compared to Case A. The thermal conditions of Case B were found to be more tolerable than those of Case A. Most respondents reported to have a calm and satisfied sleep for both cases. Comfort temperature and Sleep Efficiency Index (SEI) were found to be maintained in both cases

Evaluation of urban local-scale aerodynamic parameters: implications for the vertical profile of wind speed and for source areas

Nine methods to determine local-scale aerodynamic roughness length (z0) and zero-plane displacement (zd) are compared at three sites (within 60 m of each other) in London, UK. Methods include three anemometric (single-level high frequency observations), six morphometric (surface geometry) and one reference-based approach (look-up tables). A footprint model is used with the morphometric methods in an iterative procedure. The results are insensitive to the initial zd and z0 estimates. Across the three sites, zd varies between 5 – 45 m depending upon the method used. Morphometric methods that incorporate roughness-element height variability agree better with anemometric methods, indicating zd is consistently greater than the local mean building height. Depending upon method and wind direction, z0 varies between 0.1 and 5 m with morphometric z0 consistently being 2 – 3 m larger than the anemometric z0. No morphometric method consistently resembles the anemometric methods. Wind-speed profiles observed with Doppler lidar provide additional data with which to assess the methods. Locally determined roughness parameters are used to extrapolate wind-speed profiles to a height roughly 200 m above the canopy. Wind-speed profiles extrapolated based on morphometric methods that account for roughness-element height variability are most similar to observations. The extent of the modelled source area for measurements varies by up to a factor of three, depending upon the morphometric method used to determine zd and z0

Development of a model for generating air-conditioner operation schedules in Malaysia

The authors conducted field measurements of the air conditioner (A/C) usage behaviour of occupants in 38 dwellings in Kuala Lumpur, Malaysia to understand the stochastic nature of energy demand for A/Cs. The measured A/C operation schedules were compiled as probability density distributions of duration, start and end times, and frequency of A/C events for each day. Based on this, a simple algorithm to synthesize stochastic time patterns of A/C operation schedules was developed. The validity of the model was demonstrated through comparison with observational data

Time series data analysis of household electricity usage during el-nino in Malaysia

The aim of this research is to investigate the occupant's total electricity consumption as well as air conditioner usage behaviour in residential building located in Kuala Lumpur. The field survey was conducted between March to May, 2016 which is the hottest period during the year due to El Nino phenomenon. The results obviously show the heterogeneity of occupant's behaviour of energy usage. The total energy consumption is in the range of 9 kWh/d to 29 kWh/d. The measured energy consumption was compared with the outdoor air temperature

Determination of aerodynamic parameters of urban surfaces: methods and results revisited

Estimates of aerodynamic parameters, in particular roughness length z0 and displacement height d, are important for the analysis of the roughness of an urban surface, which affects processes that occur within the urban boundary layer such as pollutant dispersion and urban ventilation. Findings regarding the aerodynamic effects of various configurations of urban arrays were compiled from various studies. Several experimental, numerical and semi-empirical studies to estimate z0 and d were reviewed and compared with each other. The results can be summarized as follows: (1) the influence of the frontal area index (λf) on z0 is significant and their relationship has been confirmed by both experimental and numerical data; (2) compared to one-parameter and two-parameter fitting methods, the three-parameter fitting method is the least accurate; (3) the physical meaning of d remains vague because its definition as the height where surface drag acts may not be accurate for sharp-edged roughness blocks and (4) the peak values of z0 for uniform and heterogeneous block heights indicate presence of skimming or wake-interference flow effects, which may influence surface roughness. Finally, the semi-empirical models were found to be limited to cases derived from available experimental data, which normally involve uniform arrays of cubes

Does copy-resistance enhance cooperation in spatial prisoner's dilemma?

We propose a novel idea for the so-called pairwise-Fermi process by considering copy-resistance when an agent copies a neighbor's strategy, which implies that the focal agent with relatively affluent payoff vis-à-vis social average might be negative to copy her neighbor's strategy even if her payoff is less than the neighbor's payoff. Simulation results reveal that this idea with a revised strategy adaptation process significantly enhances cooperation for prisoner's dilemma games played on time-constant networks

Statistical analysis of air conditioning peak loads of multiple dwellings

Evaluation of the aggregated air-conditioning load of multiple dwellings is important for demand response through the optimum control of numerous air-conditioners (A/Cs), for development of smart-city or smart-community technologies. However, past studies have mainly focused on the characteristics of A/C load in a single household. With this background, the authors conducted statistical analysis of time-series data for A/C electricity consumption in 489 dwellings in Osaka, Japan, and 20 dwellings in Kuala Lumpur, Malaysia to grasp the feature of aggregated A/C load of multiple dwellings. The findings of this analysis are followings: 1) the aggregated A/C load peak per dwelling decreased by almost 50% as the number of dwellings increased from 1 to 10, due to the offset of the diverse time-patterns of A/C load. 2) The occurrence of the top 2.5% A/C load shows strong time and date dependency for an A/C load aggregated by many dwellings

Adaptive thermal comfort in university classrooms in Malaysia and Japan

The range of students’ classroom-based activities is generally restricted; therefore, individuals have limited options for adjusting themselves to the indoor thermal environment. This study investigated the comfort temperature and adaptive behaviour of university students in Malaysia and Japan. Classrooms in three universities (Universiti Teknologi Malaysia; Universiti Teknologi MARA, Malaysia; Kyushu University, Japan) were set to one of two conditions during the summer season: mechanical cooling (CL) mode, where AC was switched on for cooling purposes, and free-running (FR) mode, where AC was switched off. A total of 1428 responses were obtained. In Japan, 93.5% of the sample was male, while more even gender distributions were found in Malaysian samples. Additionally, clo values were generally higher amongst male respondents. In Japan, the mean comfort operative temperatures in FR mode was found to be 25.1 °C, while in Malaysia it was 25.6 °C. In CL mode, mean comfort operative temperatures were found to be 26.2 °C and 25.6 °C for Japan and Malaysia, respectively. Comfort temperatures in FR mode were compatible with Comité Européen de Normalisation (CEN) and American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) standards, while those in CL mode were mostly within Chartered Institute of Building Services Engineers (CIBSE) guidelines. While high proportions of students in both countries claimed that they did nothing to maintain their thermal comfort, the most common activity observed amongst Malaysian students was changing the AC temperature setting, due to the prevalence of CL in Malaysia