复合盐钙芒硝溶解性分析

基于钙芒硝是一种强碱盐,以四川同庆钙芒硝为例,研究其在不同种碱溶液和酸溶液下的溶解速率及溶解速度,实验发现温度越高溶解速率及溶解速度下降越迅速,使钙芒硝溶解变慢;通过化学溶解机理分析得出,其溶解后硫酸钙结晶会形成一层膜覆盖在矿物表面,减少溶解表面面积,对硫酸钠的溶解有抑制作用。     

1.5万t/a三氯氢硅生产装置研究

对1.5万t/a三氯氢硅装置进行了研究,包括开发背景、生产技术、工艺流程、注意事项、原料及动力消耗、安全与环保等。     

乳化沥青厂拌冷再生混合料配合比设计的试验研究

对乳化沥青冷再生混合料的配合比设计进行了试验研究,给出了乳化沥青冷再生混合料配合比的设计流程,结合试验段铺筑对乳化沥青冷再生混合料施工中的质量控制指标进行了试验分析,验证了配合比试验研究的方法.     

Wind modelling,validation and sensitivity study using Weather Research and Forecasting model in complex terrain

A physically-based wind model is applied to determine wind speed and direction and to conduct a model sensitivity analysis. The focus is the East African site of the Lake Turkana Wind Farm, characterized by complex terrain and high diurnal variability that creates a nocturnal jet of typically 15 m/s. Observations from three tall meteorological masts are compared with Weather Research and Forecast (WRF) model outputs. WRF is configured with four domains nested down to 900 m spatial resolution. The model is tested with initialization fields from two different sources, optimised using different grid configurations and parameterization schemes. Comparing model and data from 3 tall masts A, B and C yields that the primary source of error in WRF model simulation in a complex terrain is due to incorrect specification of boundary fields used to initialize the model. RMSEs achieved in this research are ≤2 m/s representing good model performance (Emery et al., 2001).     

Towards effective video annotation: An approach to automatically link notes with video content

The characteristics of annotations, such as highlighting, context-based notes, and organization are difficult to translate from the traditional paper-based medium to the digital format. An added challenge is how to facilitate annotations on a digital video in a collaborative distance learning environment. To explore issues in video annotation, we developed a tool called Interactive Shared Education Environment (ISEE). ISEE automatically generates hyperlinked timestamps, which we called Smartlinks, to associate the notes with their video contents. A usability study with 59 participants, following up by a small-scale eye-tracking study, was conducted to explore users’ video note-taking behaviors and to examine the effect of the new Smartlink design. Our results showed that participants with Smartlink took fewer notes, focused less on video controls and more on video content than those without Smartlink. We believe the main benefit of Smartlink is that it may offload non-learning related cognitive loads and allow users to take better notes. Findings from this study on users’ video annotation behaviors shed light on the future design of video annotation systems in both individual and collaborative environments.     

A comprehensive theoretical study of halide perovskites ABX3

Solar cells based on halide perovskites have recently been attractive due to their excellent power conversion efficiency (PCE), lower cost and simple manufacture. Here, a series of halide perovskites (ABX₃: A = CH₃NH₃, CH(NH₂)₂, Cs, Rb; B = Pb, Sn, Ge; X = I, Br, Cl, F) were investigated by Density Functional Theory (DFT) calculations, together with Shockley-Queisser Maximum Solar Cell Efficiency (S-Q) and Spectroscopic Limited Maximum Efficiency (SLME) mathematical models. The results indicate that: the electronic structure of germanium perovskites bears a close similarity to that of lead perovskites with a small energy difference between the nonbonding orbital and antibonding orbitals, but with a large energy difference comparing with that of tin perovskites (0.6–1.7 eV for CsGeI₃ at Z point of the Brillouin zone, 0.7–1.4 eV for CH₃NH₃PbI₃ and 1.4–2.2 eV for CH₃NH₃SnI₃ at R point of the Brillouin zone), which is attributable to the atomic level, where the 4s orbital energy of Ge (−11.5 eV) is close to the 6s orbital energy of Pb (−11.6 eV), but the 5s orbital energy of Sn (−10.1 eV) is significantly high. Therefore, germanium perovskites possess as high absorption coefficient around solar spectrum as lead perovskites, while tin perovskites only have low absorption coefficient, which makes the short-circuit current of CsGeI₃ and CH₃NH₃PbI₃ (0.017 Acm⁻² and 0.016 Acm⁻², simulated by SLME with a 200 nm absorber under AM1.5G) are higher than that of CH₃NH₃SnI₃ (0.015 Acm⁻²) even if the bandgap of CsGeI₃ and CH₃NH₃PbI₃ (1.51 eV and 1.55 eV) are larger than that of CH₃NH₃SnI₃ (1.21 eV). Meanwhile, the effective mass of electrons and holes are approximate for germanium perovskites and lead perovskites (0.14:0.19 for CsGeI₃ and 0.12:0.12 for CH₃NH₃PbI₃), indicating a balanced electrons and holes transport, whereas the electrons transport is much slower than the holes transport for tin perovskites due to the effective mass of electron is much larger than that of hole (0.17:0.04 for CH₃NH₃SnI₃). As a result, the PCE of CsGeI₃ (27.9%) and CH₃NH₃PbI₃ (26.7%) is higher than that of CH₃NH₃SnI₃ (19.9%).     

Mesophase features in isotactic poly(propylene‐co‐1‐heptene) copolymers

The influence of crystallization rate on the interesting polymorphism of random isotactic poly(propylene‐co‐1‐heptene) copolymers was studied, with particular attention to the conditions for obtaining the mesomorphic phase. Owing to the important decrease of cooling rate involved as the 1‐heptene content increases, the mesophase can be clearly observed by DSC for co‐unit contents above about 5 mol%. Furthermore, only the mesophase (or the amorphous phase) was found for the copolymer with 13.9 mol% 1‐heptene at common cooling rates of the calorimeter. Additionally, the copolymer with 21.4 mol% co‐units was found to be completely amorphous under any thermal treatment analyzed. Variable‐temperature diffraction experiments were carried out to ascertain unambiguously the nature of the phases involved. Finally, a remarkable transparency was attained (above 80% transmittance in the visible light region) at intermediate and high 1‐heptene contents, using easily accessible cooling rates. © 2016 Society of Chemical Industry     

Effectiveness of daylighting design and occupant visual satisfaction in a LEED Gold laboratory building

Using daylight as primary light source has been widely recognized as an important strategy to reduce building energy demand and enhance indoor environment quality. However, to design and operate a building to make full use of daylight, which is a dynamic light source, to meet diverse occupant needs remains a challenge. This paper reports a post-occupancy study of the visual environment in a laboratory building on a university campus, and puts a spotlight on the building occupants as it examines the effectiveness of the daylighting design and systems integration in creating a visual environment to support occupant comfort and satisfaction while reducing artificial lighting demand. Results show generally high satisfaction with daylit work environment and positive effect of the horizontal shading strategy. Issues about the integration between daylighting and electric lighting systems and level of occupant control are identified and discussed for improving the effectiveness of daylighting and enhancing the quality of the visual environment in the building of study. A multiple-tool methodology is developed and tested, which included occupant surveys, interviews, illuminance measurements, continuous data loggers, fisheye-lens camera and glare-identifying software, and documentation of spatial settings, systems features, and user behavior.     

Discrete sliding mode controller with reaching phase elimination for TITO systems

Sliding mode control (SMC) is emerged as a powerful robust controller for the process control application. However, it does not posses robustness properties during reaching phase and suffers from chattering, which is undesirable. In this paper, a chatter free discrete sliding mode controller (DSMC) with reaching phase elimination is proposed. The issue of existence of reaching phase due to physical constraints such as saturation of actuating devices is also addressed. The two-input–two-output (TITO) system is decoupled into two single-input–single-output (SISO) systems using ideal decoupler. The DSMCs are separately designed for two decoupled SISO systems. The stability is ensured via Lyapunov approach. Simulation study and experimentation on real life interacting two tank liquid level system are included to demonstrate effectiveness and applicability of the proposed controller.