The Novel Additive 1‐Naphthalenethiol Opens a New Processing Route to Efficiency‐Enhanced Polymer Solar Cells

Polymer solar cells (PSCs) based on fullerene derivatives often require additives to optimize active layer morphology. Here, the novel additive 1‐naphthalenethiol (SH‐na) is proposed for processing the PSC active layer of PTB7:PC₇₁BM. Spin‐casting with SH‐na as additive achieves a power conversion efficiency (PCE) of 7.3%, compared to 6.7% for preparations containing the conventional 1,8‐diiodooctane additive. Dipping of the active layer into a methanol solution of critical SH‐na concentration increases the PCE further to 8.75%. This is mainly due to an improved open‐circuit voltage (from 0.72 to 0.79 V) together with a high achieved fill factor of 0.70. The improved PCE is correlated to the morphology optimization according to measurements of grazing incidence small/wide‐angle X‐ray scattering, neutron reflectivity, atomic force microscopy, Fourier transform infrared spectroscopy, and X‐ray photoelectron spectroscopy. The integrated results suggest that the halogen‐free additive SH‐na can form hydrogen bonds with both PTB7 and PC₇₁BM, resulting in substantially improved PTB7 crystallization and multi‐length‐scale PC₇₁BM dispersion for appropriate aggregation and networks. The subsequent dipping treatment with SH‐na further modifies the active layer morphology for a more PC₇₁BM‐enriched surface and better PC₇₁BM networks in the bulk film for an optimized electron‐to‐hole mobility ratio of 2.04, hence resulting in improved device performance.     

Development of temperature-control system for liquid droplet using surface Acoustic wave devices

In this paper, we present a liquid-droplet-heating system using a surface acoustic wave (SAW) device. When liquid is placed on a Rayleigh-SAW-propagating surface, a longitudinal wave is radiated into the liquid. If the SAW amplitude increases, the liquid shows non-linear dynamics, such as vibrating, streaming, small droplet flying, and atomizing. This phenomenon is well known as SAW streaming. The liquid temperature is measured during the longitudinal wave radiation and found to increase. First, the mechanism of the liquid-heating effect is discussed on the basis of experimental results. The surface electrical condition is changed to investigate the effect of dielectric heating. The obtained results indicate that the radiated longitudinal wave causes liquid heating and the dielectric heating effect does not. Second, the fundamental properties of the liquid temperature are measured by varying the applied voltage, duty factor, and liquid viscosity. The liquid temperature is found to be proportional to the duty factor and the square of the applied voltage. Therefore, the liquid temperature can be controlled by these applied signals. Also, by using highly viscous solutions, the liquid temperature is increased to more than 100 °C. Moreover, for chemical applications, the possibility of periodic temperature control is tested by varying the duty factor. The obtained results strongly suggest that an efficient thermal cycler is realized. A novel application of the SAW device is proposed on the basis of SAW streaming.     

Basic principle and maximum torque characteristics of a six-phase pole change induction motor for electric vehicles

In addition to basic characteristics such as small size, lightweight and easy maintenance, the electric vehicle (EV) motor is required to possess characteristics that allow for the production of high torque in low-speed region and to realize a wide-speed range of constant power in high-speed region. In an attempt to improve further the constant power operation of the induction motor (IM), this paper proposes a six-phase pole change IM (six-phase PCIM). The six-phase PCIM further expands the constant power operation range without increasing either volume or current of IM. To clarify the basic principle and torque characteristics of the six-phase PCIM, its winding method and distribution of magnetomotive force (mmf) will first be examined. Then, by establishing a performance calculation method based on a quasisinusoidal wave method, the feasibility of a highly precise performance calculation sufficient for actual use will be demonstrated. Furthermore, by clarifying through experiment the maximum torque characteristics, the feasibility of expansion of the constant power operation range will be confirmed and its effectiveness in the EV will be discussed. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 118 (3): 78–91, 1997     

Separation and enrichment of carbon dioxide by capillary membrane module with permeation of carrier solution

A novel facilitated transport membrane for gas separation using a capillary membrane module is proposed in which a carrier solution is forced to permeate the membrane. Both a feed gas and a carrier solution are supplied to the lumen side (high pressure side, feed side) of the capillary ultrafiltration membrane and flow upward. Most of the carrier solution which contains dissolved solute gas, CO₂ in the present case, permeates the membrane to the permeate side (low pressure side, shell side), where the solution liberates dissolved gas to form a lean solution. The lean solution is circulated to the lumen side. This type of capillary membrane module was applied to the separation of CO₂ from model flue gases consisting of CO₂ and N₂. Monoethanolamine (MEA), diethanolamine (DEA) and 2-amino-2-methyl-1-propanol (AMP) were used as carriers or absorbents of CO₂. The feed side pressure was atmospheric and the permeate side was evacuated at about 10 kPa. CO₂ in the feed gas was successfully concentrated from 5–15% to more than 98%. The CO₂ permeance was as high as 2.7×10⁻⁴ mol m⁻² s⁻¹ kPa⁻¹ (8.0×10⁻⁴ cm³ cm⁻² s⁻¹ cmHg⁻¹) when the CO₂ mole fraction in the feed was 0.1 and temperature was 333 K. The selectivity of CO₂ over N₂ was in the range from 430 to 1790. The membrane was very stable over a discontinuous one-month testing period.     

Fluoroalkyl end‐capped oligomer possessing a nonflammable characteristic in silica gel matrices even at 800°C under atmospheric conditions

We succeeded in observing the similar solid‐state NMR spectra (¹H‐magic‐angle spinning NMR spectra) of fluoroalkyl end‐capped N‐(1,1‐dimethyl‐3‐oxobutyl)acrylamide oligomer [R_F‐(DOBAA)_n‐R_F]/silica gel nanocomposite before and even after calcinations at 800°C. This finding suggests that R_F‐(DOBAA)_n‐R_F oligomer in R_F‐(DOBAA)_n‐R_F/silica gel nanocomposite can afford a nonflammable characteristic to exhibit no weight loss behavior even at 800°C under atmospheric conditions. In addition, we had good oleo‐ and hydrophobic characteristics on the modified glass surface treated with R_F‐(DOBAA)_n‐R_F/silica gel nanocomposite even after calcination at 800°C as well as those before calcinations. Especially, R_F‐(DOBAA)_n‐R_F/silica gel nanocomposite‐encapsulated cetylpyridinium chloride (CPC) possessing no weight loss characteristic even at 800°C exhibited a clear UV–vis absorption band around 260 nm related to the presence of CPC before and even after calcinations at 800°C. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Reservoir characteristics and development plan of the Oguni geothermal field, Kyushu, Japan

Geothermal power development at the Oguni field, central Kyushu, is planned to begin in the year 2001 with a double flash system generating 20 MW_e. The Oguni reservoir has been delineated by systematic geothermal surveys, well tests and reservoir engineering studies. The fractured reservoir is horizontally layered and divided into northern and southern portions. Both of them have NaCl dominant fluids ranging from 200 to 240°C. The northern reservoir covers a large area including the Takenoyu Fault Zone and has a relatively high permeability (kh≈80–230 darcy-m). By contrast, the southern reservoir covers a relatively small area and has limited transmissivity. The southern reservoir has a higher pressure (1 MPa) than the northern reservoir, indicating little connectivity between them. Based on numerical calculations, as well as the surface topography and environmental aspects, the production and reinjection zones have been separated, and a large part of the necessary fluid will be produced from the northern reservoir along the Takenoyu Fault and a small part will be taken from the southern reservoir. The separated water will be reinjected into the northernmost part of the northern reservoir, in order to prevent a cold sweep problem for production.     

Mechanical Property Evolution during Autoclaving Process of Aerated Concrete Using Slag: I, Tobermorite Formation and Reaction Behavior of Slag

The chemical reactions in the formation of autoclaved aerated concrete (AAC) block were investigated. The samples were prepared using blast furnace slag at 180°C under saturated steam pressures for various times from 1 to 128 h. Autoclaving for 1 h yielded 1.1-nm tobermorite with higher Al substitution and lower Ca/(Al + Si) ratio than that made without slag, due to the high solubility of the slag during the initial stage of reaction. This suggests that the utilization of slag has an advantage of reducing processing time. On further reaction, the crystallinity of the tobermorite increases and its Ca/(Al + Si) ratio decreases, becoming constant after 64 h. After a long period of autoclaving. thick reaction rims are formed around unreacted slag particles, interrupting the diffusion of Ca from slag to matrix.     

Seismic reflector imaging by prestack time migration in the Kakkonda geothermal field, Japan

We show that a prestack migration method improves the S/N ratio of seismic reflection profiling in the Kakkonda geothermal field where seismic reflection data are of poor quality. We use non-iterative prestack time migration (PSTM), which does not require multiple iterations to determine the velocity structure for prestack time migration. The optimum constant migration velocity can be determined at each image point from a migration velocity analysis based on primary diffraction patterns. Our results delineate a strong reflector beneath a zone of high seismicity. According to the correspondence between the fracture distribution, the distribution of microearthquakes, and geothermal structure, this reflector is interpreted to be a zone of low-angle fractures saturated with hydrothermal fluids, and to be strongly controlled by the geothermal structure.