Observation of asymmetric electromagnetic field profiles in chiral metamaterials

We experimentally observe asymmetric electromagnetic field profiles along two-dimensional chiral metamaterials. The asymmetric field profiles depending on the chirality and the operation frequency have been reproduced well by the numerical simulation. Around a chiral meta-atom, distribution of a Poynting vector is found to be shifted asymmetrically. These results are explained in terms of an analogy with the side-jump mechanism in the electronic anomalous Hall systems

Chemical kinetics and CFD analysis of supercharged micro-pilot ignited dual-fuel engine combustion of syngas

A comprehensive chemical kinetics and computational fluid-dynamics (CFD) analysis were performed to evaluate the combustion of syngas derived from biomass and coke-oven solid feedstock in a micro-pilot ignited supercharged dual-fuel engine under lean conditions. The developed syngas chemical kinetics mechanism was validated by comparing ignition delay, in-cylinder pressure, temperature and laminar flame speed predictions against corresponding experimental and simulated data obtained by using the most commonly used chemical kinetics mechanisms developed by other authors. Sensitivity analysis showed that reactivity of syngas mixtures was found to be governed by H2 and CO chemistry for hydrogen concentrations lower than 50% and mostly by H2 chemistry for hydrogen concentrations higher than 50%. In the mechanism validation, particular emphasis is placed on predicting the combustion under high pressure conditions. For high hydrogen concentration in syngas under high pressure, the reactions HO2 + HO2 = H2O2 + O2 and H2O2 + H = H2 + HO2 were found to play important role in in-cylinder combustion and heat production. The rate constants for H2O2 + H = H2 + HO2 reaction showed strong sensitivity to high-pressure ignition times and has considerable uncertainty. Developed mechanism was used in CFD analysis to predict in-cylinder combustion of syngas and results were compared with experimental data. Crank angle-resolved spatial distribution of in-cylinder spray and combustion temperature was obtained. The constructed mechanism showed the closest prediction of combustion for both biomass and coke-oven syngas in a micro-pilot ignited supercharged dual-fuel engine

CO2 concentration measurements inside expansion-compression engine under high EGR conditions using an infrared absorption method

The purpose of this study is to measure the high concentrations of CO2 near a spark plug inside an internal combustion engine, and an infrared absorption method is used for the measurement. The spark plug sensor was adapted to a compression-expansion machine, and the CO2 concentration near the spark plug was measured by adding a gas mixture, including CO2 to imitate EGR. Next, the EGR ratio was changed from 10 to 40%, and the CO2 concentration was measured. The effect of the CO2 on the flame propagation was investigated by visualizing the bottom view of the compression-expansion machine. The measurements of CO2 mass concentration are in agreement with those predicted by direct-absorption spectroscopy fundamental theory from the crank angle −60 to −15 deg ATDC. The error was less than 20%, and under the conditions with an EGR ratio of 20–40%.The purpose of this study is to measure the high concentrations of CO2 near a spark plug inside an internal combustion engine, and an infrared absorption method is used for the measurement. The spark..

Microwave analog of Stern-Gerlach effects using nonuniform chiral metamaterials

This study observes microwave beam splitting dependent on circular polarizations through nonuniform chiral metamaterials. Nonuniform chiral metamaterials with a gradation in refractive index are constructed using chiral meta-atoms that exhibit optical activities at microwave frequencies. Microwave scattering far-field patterns by the nonuniform chiral metamaterials demonstrate a deflection of microwaves, which transmit in a direction perpendicular to the refractive index gradient. Furthermore, circularly polarized microwaves with opposite “spins of light” go their separate ways in the nonuniform chiral metamaterials. This phenomenon is an optical analog of the Stern-Gerlach effects for electrons

Quantum cascade laser assisted time-resolved measurements of carbon dioxide absorption during combustion in DME-HCCI engine

We conducted experiments to investigate in-cylinder light absorption by carbon dioxide (CO2) during homogeneous charge compression ignition (HCCI) engine combustion. The combustion was fuelled with dimethyl ether. An in situ laser infrared absorption method was developed. We used an optical fibre spark plug sensor and the light source was a 4.301 μm quantum cascade laser (QCL). We applied Lambert–Beer’s law in the case of a single absorption line of CO2. We were able to measure the transient CO2 formation during the HCCI combustion inside the engine cylinder. Our experiments showed that the laser light transmissivity level decreased with the intensity of the infrared (IR) signal. We compared the change in the transmissivity to the spatially integrated HCCI flame luminosity level and observed significant correlations between the flame luminosity level, heat release rate and transmissivity. Time-resolved experiments showed that the CO2 absorbance increases when the second peak of the rate of heat release (ROHR) is maximised. After combustion, the CO2 concentration was approximately 4 vol%, which agrees with the amount of CO2 formed during complete combustion

外科的に切除しえた, 肝硬変を伴う維持透析患者に発症した右腎癌下大静脈腫瘍塞栓の1例

症例は54歳, 男性。1900年, CGNにて血液透析導入となった。2005年2月に肉眼的血尿が出現。CTにて右腎癌を指摘され, 3月9日当科紹介。当科にて施行したCTでは直径7cm大の右腎腫瘍とともに下大静脈内の肝静脈流入部まで達する腫瘍塞栓を認めた。右腎腫瘍, 下大静脈塞栓, T3bN0M0 stage IIIの診断で4月28日, 根治的右腎摘除ならびに腫瘍塞栓摘除術を施行した。手術時間4時間28分, 出血量1, 400ml, 摘出標本は重量800g, 病理所見はrenal cell carcinoma, G2, pT3bであった。術前の凝固系検査は異常を認めなかったが, 肝硬変が原因と考えられる出血時間の延長と血小板数の低下を認めたため, 周術期は血小板輸血などにて対応した。術後経過は良好で, 後出血などの術後合併症もなく, 術後18日目に退院した。現在IFNα投与にて後療法を施行中であるが, 再発を認めていない。透析患者における下大静脈腫瘍塞栓を伴う腎癌に対して外科的治療を施行した症例についての報告例については比較的少なく, 文献的考察も含めて報告する。(著者抄録)A 54-year-old man who had been under hemodialysis therapy for 16 years presented with gross hematuria at our department in February 2005. Imaging findings revealed right renal tumor of8.2 cm in diameter. In addition, the tumor extended into inferior vena cava at the level of the hepatic vein. There were no findings of distant metastasis. Right radical nephrectomy and thrombectomy were performed on April 2006. Histopathological analysis showed that the tumor was renal cell carcinoma of clear cell type, grade 2. Postoperative course was uneventful, and the adjuvant therapy with interferon alpha was initiated. He has been free from recurrence for 22 months after surgery