Life-Cycle Assessment: Reducing Environmental Impact Risk with Workflow Data You Can Trust

How can architects offer proof of their proposals' ‘green’ credentials? The answer – as advocated by John Cays , Associate Dean of the New Jersey Institute of Technology's College of Architecture and Design – is through life-cycle assessment (LCA). Here he explains what it is, tracing its evolution over some six decades. He goes on to describe how design firms are partnering with software developers to create LCA tools that work alongside building information modelling to generate reliable data on their projects' ecological profiles.     

KOH热湿腐蚀法准确估算GaN的位错密度

实验目的在于解决GaN外延层中六方形腐蚀坑起源问题存在的分歧,并利用腐蚀法准确地估计GaN的位错密度.大量对熔融KOH腐蚀GaN过程中表面形貌的演化以及温度和时间对腐蚀结果影响的实验结果表明,位错类型与腐蚀坑三维形状相对应,而与腐蚀坑大小无关,极性是GaN不同种类位错的腐蚀坑具有不同形状的决定性因素.使所有缺陷都显示出来所需的腐蚀温度和时间呈反比关系.腐蚀法估算GaN位错密度的准确性取决于优化的腐蚀条件和合理的微观观测方法.     

Cd补偿垂直布里奇曼法生长Cd0.9Zn0.1Te晶体

采用传统垂直布里奇曼法和Cd补偿垂直布里奇曼法,分别生长出两根尺寸为 30mm×130mm的Ccd0.9Zn0.1Te晶锭.测试了晶体的结晶质量、成分分布、位错腐蚀坑密度(EPD)、红外透过率及电阻率.结果表明,Cd补偿垂直布里奇曼法生长的晶体结晶质量好、成分分布均匀、EPD低、红外透过性能好且电阻率高.这说明Cd补偿垂直布里奇曼法是一种生长高阻值CZT晶体的优良方法.     

Monte Carlo simulations of the Galileo energetic particle detector

Monte Carlo radiation transport studies have been performed for the Galileo spacecraft energetic particle detector (EPD) in order to study its response to energetic electrons and protons. Three-dimensional Monte Carlo radiation transport codes, MCNP version 4B (for electrons) and MCNPX version 2.2.3 (for protons), were used throughout the study. The results are presented in the form of “geometric factors” for the high-energy channels studied in this paper: B1, DC2, and DC3 for electrons and B0, DC0, and DC1 for protons. The geometric factor is the energy-dependent detector response function that relates the incident particle fluxes to instrument count rates. The trend of actual data measured by the EPD was successfully reproduced using the geometric factors obtained in this study.     

Anode Supported Protonic Solid Oxide Fuel Cells Fabricated Using Electrophoretic Deposition

Intermediate temperature solid oxide fuel cells (IT‐SOFCs) were fabricated depositing proton conducting BaCe_0.9Y_0.1O_3–x (BCY10) thick films on cermet substrates made of nickel oxide–yttrium doped barium cerate (NiO–BCY10) using electrophoretic deposition (EPD) technique. The influence of the EPD parameters on the microstructure and electrical properties of BCY10 thick films was investigated. Deposited BCY10 thick films together with green anode substrates were co‐sintered in a single heating treatment at 1,550 °C for 2 h to obtain dense electrolyte and suitably porous anodes. The half‐cells were characterised by field emission scanning electron microscopy (FE‐SEM) and by X‐ray diffraction (XRD) analysis. A composite cathode specifically developed for BCY electrolytes, made of La_0.8Sr_0.2Co_0.8Fe_0.2O₃(LSCF, mixed oxygen‐ion/electronic conductor) and BaCe_0.9Yb_0.1O_3–δ (10YbBC, mixed protonic/electronic conductor), was used. Fuel cells were prepared by slurry coating the composite cathode on the co‐sintered half‐cells. Fuel cell tests and electrochemical impedance spectroscopy (EIS) were performed in the 550–700 °C temperature range. A maximum power density of 296 mW cm^–2 was achieved at 700 °C for electrolyte deposited at 60 V for 1 min.     

用于电泳沉积的TiO2悬浮液分散性能研究

为了制备适合电泳沉积用的稳定悬浮液,在TiO2水基悬浮液中添加了聚乙烯亚胺(PEI)作为分散剂,对TiO2水基悬浮液进行Zeta电位、黏度、粒径以及稳定性测试,研究了PEI分散剂对TiO2分散性能的影响.结果表明通过添加相对于悬浮液中TiO2粉体质量分数0.6%～3.0%的分散剂可以获得高稳定、高分散、低黏度的悬浮液.     

Microcup® displays: Electronic paper by roll‐to‐roll manufacturing processes

Abstract— Rolls of flexible displays or electronic paper have recently been prepared by a high‐speed roll‐to‐roll manufacturing process based on SiPix's novel Microcup® and top‐sealing technologies. Both Microcup® electrophoretic displays (EPDs) and LCDs have been demonstrated. The display rolls are format flexible and may be cut into desirable size and shape for a variety of applications. High‐performance flexible passive‐matrix Microcup® EPDs having a wide range of threshold voltages have also been demonstrated.     

Effect of TiO2 photo-electrode growth condition on dye-sensitised solar cells

Titanium dioxide- (TiO₂) based photo-electrode for dye-sensitised solar cells (DSSCs) use is fabricated with the electro-phoretic deposition (EPD) technique on indium-tin-oxide (ITO). TiO₂ films were synthesised at different EPD biases ranging from 70 to 110 V. We correlate the morphological and optical properties of formed films to the electrical characteristics of fabricated DSSCs. In addition, by neglecting the tunnelling and the tunnelling-assisted thermo-ionic currents with respect to the pure thermo-ionic current at the ITO/TiO₂ interface, we evaluate the high potential barrier, e?_B. Investigation of the electrical properties of the formed DSSCs shows a best result when the TiO₂ film is elaborated at 100 V. Furthermore, by taking into account the high band energy of 0.6 eV at an aluminium-based counter electrode/electrolyte interface, we deduce that aluminium reduces drastically the short-circuit current of the DSSC.     

Growth of a Ge layer on 8 in. Si (100) substrates by rapid thermal chemical vapor deposition

We have made the successful growth of Ge layer on 8 in. Si (100) substrates by rapid thermal chemical vapor deposition (RTCVD). In order to overcome the large lattice mismatch between Ge and Si, we used a two-step growth method. Our method shows the uniformity of the thickness and good quality Ge layer with a homogeneous distribution of tensile strain and a lower etch pit density (EPD) in order of 10⁵ cm⁻². The surface morphology is very smooth and the root mean square (RMS) of the surface roughness was 0.27 nm. The photocurrent spectra were dominated by the Ge layer related transition that corresponding to the transitions of the Si and Ge. The roll-off in photocurrent spectra beyond 1600 nm is expected due to the decreased absorption of Ge.     

Low threading dislocation density GaAs on Si(100) with InGaAs/GaAs strained-layer superlattice grown by migration-enhanced epitaxy

This paper reports a promising approach for reducing the density of threading dislocations in GaAs on Si. In _x Ga_1-x As/GaAs strained-layer superlattices (SLSs) grown by migration-enhanced epitaxy at 300° C on GaAs/Si acted as barriers to threading dislocations. Unlike conventional high-temperature-grown SLSs, the low-temperature-grown SLSs were hardly relaxed by the formation of misfit dislocations at GaAs/SLS interfaces, and this allowed them to accumulate considerable strain. New threading dislocation generation due to the misfit dislocation was also suppressed. These factors caused effective bending of threading dislocations and significantly reduced the dislocation density. For the samples that had an SLS withx = 0.3, the average etch-pit density was 7 × 10⁴ cm^-2, which is comparable to that of GaAs substrates.