Thin film solar cells incorporating microcrystalline Si1–xGex as efficient infrared absorber: an application to double junction tandem solar cells

We have fabricated efficient (∼7–8%) hydrogenated microcrystalline Si_1–xGe_x (µc‐Si_1–xGe_x:H, x ∼ 0.1–0.17) single junction p‐i‐n solar cells with markedly higher short‐circuit current densities than for µc‐Si:H (x = 0) solar cells due to enhanced infrared absorption. By replacing the conventional µc‐Si:H with the µc‐Si_1–xGe_x:H as infrared absorber in double junction tandem solar cells, the bottom cell thickness can be reduced by more than half while preserving the current matching with hydrogenated amorphous silicon (a‐Si:H) top cell. An initial efficiency of 11.2% is obtained for a‐Si:H/µc‐Si₀.₉Ge₀.₁:H solar cell with bottom cell thickness less than 1 µm. Copyright © 2009 John Wiley & Sons, Ltd.     

Proliferation of district heating using local energy resources through strategic building-stock management: A case study in Fukushima,Japan

District heating systems using cogeneration technology and renewable resources are considered as an effective approach to resources conservation and reduction of greenhouse gas (GHG) emissions. However, widespread aging and depopulation problems, as well as the popularization of energy-saving technologies in buildings, are estimated to greatly decrease energy consumption, leading to inefficiency in district heating and barriers to technology proliferation. From a long-term perspective, land use changes, especially the progression of compact city plans, have the potential to offset the decrement in energy consumption that maintains the efficiency of district heating systems. An integrated model is developed in this paper based on building cohort analysis to evaluate the economic feasibility and environmental impact of introducing district heating systems to a long-term compact city plan. As applied to a case in the Soma Region of Fukushima, Japan, potential migration from the suburbs to the central station districts is simulated, where district heating based on gas-fired cogeneration is expected to be introduced. The results indicate that guided migration to produce concentrated centers of population can substantially increase the heat demand density, which supports a wider application of district heating systems and better low-carbon performance. These results are further discussed in relation to technology innovation and related policies. It is concluded that policies related to urban land use planning and energy management should be integrated and quantitatively evaluated over the long-term with the aim of supporting urban low-carbon sustainable development.     

The Potential of Using an Autogenous Tendon Graft by Injecting Bone Marrow Aspirate in a Rabbit Meniscectomy Model

Bone marrow aspirate (BMA) is an excellent source of cells and growth factors and has been used successfully for bone, cartilage, and soft-tissue healing. This study aimed to investigate the histological and biomechanical properties of autogenous tendon graft by injecting BMA and its protective effect against degenerative changes in a rabbit model of meniscal defects. Adult white rabbits were divided into untreated, tendon, and tendon + BMA groups, and meniscal defects were created in the knees. The tendon graft and articular cartilage status were evaluated by macroscopic and histological analysis at 4, 12, and 24 weeks postoperatively among the three groups. The tendon graft in the tendon and tendon + BMA groups were used for biomechanical evaluation at 4, 12, and 24 weeks postoperatively. The meniscal covering ratio in the tendon + BMA group was better than that in the tendon and untreated groups at 12 and 24 weeks postoperatively. The matrix around the central portion of cells in the tendon + BMA group was positively stained by safranin O and toluidine blue staining with metachromasia at 24 weeks. The histological score of the tendon graft in the tendon + BMA group was significantly higher than that in the untreated and tendon groups at 12 and 24 weeks postoperatively. In the tendon + BMA group, cartilage erosion was not shown at 4 weeks, developed slowly, and was better preserved at 12 and 24 weeks compared to the untreated and tendon groups. Histological scores for the articular cartilage were significantly better in the tendon + BMA group at 24 weeks. The compressive stress on the tendon graft in the tendon + BMA group was significantly higher than that in the tendon group at 12 weeks postoperatively. Transplantation of autogenous tendon grafts by injecting BMA improved the histologic score of the regenerated meniscal tissue and was more effective than the tendon and untreated group for preventing cartilage degeneration in a rabbit model of massive meniscal defects.     

Non-Invasive Tear Break-Up Detection with the Kowa DR-1α and Its Relationship to Dry Eye Clinical Severity

The purpose of this study is to compare visual versus software detection of non-invasive tear break-up with the KOWA DR-1α tear interferometer and investigate the relationship between non-invasive tear break-up time (NIBUT) and dry eye clinical severity. Tear interferometry with the KOWA DR-1α, together with a standardized comprehensive ocular surface/tear evaluation, was performed on 348 consecutive eyes. Investigator visually detected or software detected non-invasive tear break-up and NIBUT were measured and compared on a subset of these examinations. The relationship between software-detected NIBUT and categorical dry eye severity based on irritation symptoms and corneal and conjunctival dye staining scores was determined. The sensitivity of visual (frame-by-frame) or software detected non-invasive tear break-up in eyes with tear instability (FBUT < 10) was similar (range 63–69%). NIBUT, measured visually or by software, had a correlation coefficient of 0.87. NIBUT was significantly lower in severity levels 2 and 3 compared to levels 0 + 1, and level 3 was significantly lower than level 2. In conclusion, there is a good correlation between investigator visually detected and software-detected tear break-up and tear break-up time in the KOWA DR-1α interferometric fringe images. Software-detected NIBUT is a clinically relevant measure of dry eye clinical severity.     

电子鼻结合GC-MS检测沙拉酱对挪威三文鱼风味的影响

为探究沙拉酱对三文鱼风味的影响,利用电子鼻技术结合顶空固相微萃取技术(HS-SPME)与气相色谱-质谱技术(GC-MS),对添加沙拉酱前后的三文鱼样品挥发性风味物质进行鉴定与比较。结果表明:通过感官实验分析,香甜味沙拉酱、原味沙拉酱与三文鱼食用比例分别确定为1:6、1:7时食品口感最佳,符合大多数人的感官需求。通过对电子鼻传感器响应值的分析比较及主成分分析得出,添加两种不同沙拉酱后三文鱼样品的醇醛类、碳氧化合物、有机化合物等物质均显著增加(P<0.05),添加沙拉酱前后的三文鱼样品具有较好的区分度,并且经GC-MS鉴定添加了沙拉酱以后三文鱼样品的醛酮类、醇类、酯类、酸类、烃类物质等含量显著增加(P<0.05),尤其是酯类和酸类物质的含量较多,检测结果与电子鼻分析结果较为一致。同时添加沙拉酱后检测三文鱼中的庚醛、己醛等腥味物质都有所降低,1-辛烯-3-醇未检测出,说明沙拉酱可以掩盖三文鱼某些腥味物质。综合来看,添加沙拉酱后不仅可以促进三文鱼食品整体风味物质的形成,还可以掩盖三文鱼中的腥味物质,从而进一步提高三文鱼食品的感官评分及营养价值。     

沙拉酱风味鱼糜制品制备及其挥发性物质分析

为探究沙拉酱风味鱼糜制品的工艺配方,本研究以感官评分、白度和凝胶强度为评价指标,通过单因素实验和正交试验确定其最优配方,并在此基础上利用GC-MS对沙拉酱风味鱼糜制品的挥发性物质进行了相关分析。结果表明：沙拉酱风味鱼糜制品的最优配方为：以鱼糜质量为基数,食盐添加量为2.5%,白糖添加量为2.5%,料酒添加量为1.0%,沙拉酱添加量为8.0%,马铃薯淀粉添加量为7.0%,蛋清添加量为5.0%,每100.0 g鱼糜中的冰水添加量为83.0 g。通过GC-MS分析可知添加沙拉酱后,水产品腥味物质有所降低,沙拉酱中特有的挥发性风味物质醋酸和异硫氰酸烯丙酯等挥发性风味物质均有检出,极大的改善了鱼糜制品的风味。     

Features of Particle and Heavy Ion Transport code System (PHITS) version 3.02

We have upgraded many features of the Particle and Heavy Ion Transport code System (PHITS) and released the new version as PHITS3.02. The accuracy and the applicable energy ranges of the code were greatly improved and extended, respectively, owing to the revisions to the nuclear reaction models and the incorporation of new atomic interaction models. Both condense history and track-structure methods were implemented to handle the electron and positron transport, although the latter is reliable only for simulations in liquid water. In addition, several user-supportive functions were developed, such as new tallies to efficiently obtain statistically better results, radioisotope source-generation function, and software tools useful for applying PHITS to medical physics. Owing to the continuous improvement and promotion of the code, the number of registered users has exceeded 3,000, and it is being used in diverse areas of study, including accelerator design, radiation shielding and protection, medical physics, and cosmic-ray research. In this paper, we summarize the basic features of PHITS3.02, especially those of the physics models and the functions implemented after the release of PHITS2.52 in 2013.     

Dielectric response and polarization mechanism of alkali silicate glasses in gigahertz to terahertz frequency range

Oxide glasses are dielectric materials with potential applications in high-frequency communications; hence, their dielectric properties in the gigahertz to terahertz frequency range should be investigated. In this study, the dielectric properties of silica glass and five single alkali silicate glasses were measured at 0.5–10 THz using terahertz time-domain spectroscopy and far-infrared spectroscopic ellipsometry. At 0.5–10 THz, the silica glass exhibited low dielectric dispersion with a low dielectric constant and loss. By contrast, the alkali silicate glasses exhibited high dielectric dispersion, and the dielectric constant and loss were higher than those of the silica glass. The shape of the dielectric dispersion profile depended on the alkali-metal ions; it was broader for lighter ions such as Li ions and sharper for heavier ions such as Cs ions. The peak dielectric loss shifted toward a lower frequency as the weight of the alkali-metal ions in the alkali-silicate glass increased. To understand the dielectric dispersion, the complex permittivity was calculated using molecular dynamics simulations. The theoretical results qualitatively agreed with the experimental data. Ion dynamics analysis revealed that alkali-metal ions vibrate and migrate under an applied electric field, which affects the dielectric constant and loss of alkali-silicate glasses at gigahertz to terahertz frequencies. To fabricate filter devices at low temperatures, alkali metals should be added to silicate glass; therefore, a minimum amount of light alkali metals should be used to minimize the dielectric loss of the glass materials while maintaining productivity.