日本城市绿地政策发展的回顾及现行控制性绿地政策我国的启示

我国过热的城市开发对城市绿地的保护造成了很大的压力,且尚无较为有效的对策.通过回顾日本城市绿地政策的理论形成及应用实践,探讨日本<城市绿地法>等一系列法律中控制性绿地的保护法规的实行对城市绿地保护产生的效果,从中探求我国今后城市绿地政策发展中可借鉴的经验及教训.     

High-rate microcrystalline silicon deposition for p–i–n junction solar cells

We have developed a high-rate plasma process based on high-pressure and silane-depletion glow discharge for highly efficient microcrystalline silicon (μc-Si:H) p–i–n junction solar cells. Under high-rate conditions (2–3 nm/s), we find that the deposition pressure becomes the dominant parameter in determining solar-cell performance. With increasing deposition pressure from 4 to 7–9 Torr, short-circuit current increases by 50% due to a remarkable improvement in quantum efficiencies at the visible and near infrared. As a result, the maximum efficiency of 9.13% has been achieved at an i-layer deposition rate of 2.3 nm/s. We attribute the improved performance of high-pressure-grown μc-Si:H solar cells to the structural evolution toward denser grain arrangement that prevents post-oxidation of grain boundaries.     

Design and characterization of nanoknife with buffering beam for in situ single-cell cutting

A novel nanoknife with a buffering beam is proposed for single-cell cutting. The nanoknife was fabricated from a commercial atomic force microscopy (AFM) cantilever by focused-ion-beam (FIB) etching technique. The material identification of the nanoknife was determined using the energy dispersion spectrometry (EDS) method. It demonstrated that the gallium ion pollution of the nanoknife can be ignored during the etching processes. The buffering beam was used to measure the cutting force based on its deformation. The spring constant of the beam was calibrated based on a referenced cantilever by using a nanomanipulation approach. The tip of the nanoknife was designed with a small edge angle 5° to reduce the compression to the cell during the cutting procedure. For comparison, two other nanoknives with different edge angles, i.e. 25° and 45°, were also prepared. An in situ single-cell cutting experiment was performed using these three nanoknives inside an environmental scanning electron microscope (ESEM). The cutting force and the sample slice angle for each nanoknife were evaluated. It showed the compression to the cell can be reduced when using the nanoknife with a small edge angle 5°. Consequently, the nanoknife was capable for in situ single-cell cutting tasks.     

New measuring method for determining alignment parameters in twisted‐nematic and super‐twisted‐nematic cells

Abstract— A new method for determining the thickness, twist angle, and azimuth of the director for a substrate with twisted‐nematic (TN) and super‐twisted‐nematic (STN) liquid‐crystal (LC) cells has been proposed. The measurement was carried out by using an optical system which consisted of a monochromatic light source, polarizer, rotating analyzer, and software programs. The polarization transfer matrix, or Jones matrix, of a TN or an STN LC cell is formulated by the Fourier coefficient of the signal that is modulated by the rotating analyzer. These three alignment parameters are derived directly from components of the Jones matrix. We made a special effort to design the system to ensure accurate, stable, and quick measurement. Thus, the three parameters were determined simultaneously within a few seconds with good reproducibility; e.g., the standard deviation of the twist angle in the TN cell is 0.02° or less.     

An Attempt to Evaluate the Subsite Structure of Cycloamylose glucanotransferase from Bacillus stearothermophilus: Based on its Transfer Reaction with Substrate Malto-oligosaccharides

Based on determination of the transferred products (maltooligosaccharides G_n), the plausible degradation modes of G₂, G₃, and G₄ were analyzed quantitatively, and it was made an attempt to evaluate the binding affinity A_i on some subsites of cycloamylose glucanotransferase (CGT) from Bacillus stearothermophilus. This method can be employed instead of the technique using a radioisotope. The quantities of the substrates (G₂–G₄) and products G_n were measured by using the HPLC techniques as a function fo time for the CGT-catalysed reaction.     

Bandgap Tunable Oxynitride LaNb2O7–xNx Nanosheets

Bandgap tunable lanthanum niobium oxynitride [LaNb₂O_7-xN_x]^(1+x)− nanosheet is prepared by the delamination of a Ruddlesden−Popper phase perovskite oxynitride via ion−exchange and two−step intercalation processes. The lanthanum niobium oxynitride nanosheets have a homogeneous thickness of 1.6 nm and exhibit a variety of chromatic colors depending on the nitridation temperature of the parent-layered oxynitride. The bandgap energy of the nanosheets is determined by ultraviolet photoemission spectroscopy, Mott–Schottky, and photoelectrochemical measurements and is found to be tunable in the range of 2.03–2.63 eV. Furthermore, the oxide/oxynitride superlattice structures are fabricated by face−to−face stacking of 2D crystals using oxynitride [LaNb₂O_7-xN_x]^(1+x)− and oxide [Ca₂Nb₃O₁₀]⁻ nanosheets as building blocks. Moreover, the superlattices-like restacked oxynitride/oxide nanosheets hybrid exhibits unique proton conductivity and dielectric properties strongly influenced by the oxynitride nanosheets and enhanced photocatalytic activity under visible light irradiation.