Direct Semiconductor Wafer Bonding in Non-Cleanroom Environment: Understanding the Environmental Influences on Bonding

We investigated semiconductor direct wafer bonding in a regular, non-cleanroom environment to understand environmental influences on bonding characteristics. The correlations among surface treatments, particle densities, bonding strengths, and interfacial conductivities were systematically investigated. On the basis of our investigation and condition optimization, we realized direct semiconductor bonding in the regular atmosphere with high interfacial mechanical stabilities and electrical conductivities, sufficient for device applications. Furthermore, we demonstrated fabrication and operation of solar cells using the developed bonding technique, with current paths across the bonded interfaces. These results and related technical insights may be useful for a low-cost, simpler manufacture of high-performance electrical and optical devices

Wavelength-Conversion-Material-Mediated Semiconductor Wafer Bonding for Smart Optoelectronic Interconnects

A new concept of semiconductor wafer bonding, mediated by optical wavelength conversion materials, is proposed and demonstrated. The fabrication scheme provides simultaneous bond formation and interfacial function generation, leading to efficient device production. Wavelength-converting functionalized semiconductor interfacial engineering is realized by utilizing an adhesive viscous organic matrix with embedded fluorescent particles. The bonding is carried out in ambient air at room temperature and therefore provides a cost advantage with regard to device manufacturing. Distinct wavelength conversion, from ultraviolet into visible, and high mechanical stabilities and electrical conductivities in the bonded interfaces are verified, demonstrating their versatility for practical applications. This bonding and interfacial scheme can improve the performance and structural flexibility of optoelectronic devices, such as solar cells, by allowing the spectral light incidence suitable for each photovoltaic material, and photonic integrated circuits, by delivering the respective preferred frequencies to the optical amplifier, modulator, waveguide, and detector materials

Investigation of combustion noise generated by an open lean-premixed H₂/air low-swirl flame using the hybrid LES/APE-RF framework

An open lean-premixed hydrogen/air low-swirl (LPHALS) turbulent flame exhibiting a pronounced peak in its combustion noise spectra, is investigated numerically using a hybrid Computational Fluid Dynamics/Computational Aero-Acoustics (CFD/CAA) framework. Under this framework, the reacting flow-field of the flame is computed via Large-Eddy Simulation (LES), while the direct combustion noise it produces is captured by solving the Acoustic Perturbation Equations for Reacting Flows (APE-RF). Flame configuration and simulation conditions correspond to those of an experimental study on an open lean-premixed H₂/air flame stabilized using a Low-Swirl Burner (LSB). LES results are validated against experimental data. The CAA simulation is able to predict a pronounced sharp peak in the computed combustion noise spectra, similar to one of the two characteristic peaks observed in the measured combustion noise spectra. Frequency of this spectral peak predicted by the CAA simulation is 840 Hz, which is close to that of the higher frequency secondary spectral peak at 940 Hz measured in the experiment. Upon examining the hybrid LES/APE-RF results, the noise generation mechanism at 840 Hz is found to be the intense local heat release rate fluctuations, caused by strong interaction between the flame and the periodically generated vortical flow structures in the shear layers, downstream of the LSB exit. Additionally, analysis of the spectral content and directivity of the noise generated by different acoustic source terms is performed, in order to investigate their impact on the radiated acoustic field, and hence the characteristics of direct combustion noise produced by the open LPHALS flame

Combined use of an epidural cooling catheter and systemic moderate hypothermia enhances spinal cord protection against ischemic injury in rabbits

BackgroundEpidural placement of a cooling catheter can protect against ischemic spinal cord injury. With the use of rabbits, we investigated whether this epidural cooling technique, when combined with systemic moderate hypothermia, can protect the spinal cord against ischemic metabolic stress.MethodsNew Zealand white rabbits (n = 28) were assigned to 1 of 4 different groups. Animals underwent abdominal aortic occlusion for 30 minutes using a 3F balloon catheter. Group 1 (n = 7) underwent epidural cooling by the catheter and systemic moderate hypothermia (35°C) induced with a cooling blanket. Group 2 (n = 7) underwent epidural cooling under systemic normothermia (38.5°C). Group 3 (n = 7) underwent systemic moderate hypothermia (35°C) without epidural cooling. Group 4 (n = 7) underwent neither epidural nor blanket cooling as a negative control. Neurologic status of their hind limbs was graded according to the modified Tarlov scale at 1, 2, and 7 days after surgery.ResultsDuring infrarenal aortic ischemia, epidural temperature was significantly lower in group 1 (18.5°C ± 0.8°C) than in group 2 (28.6°C ± 1.0°C; P = .0001), group 3 (34.2°C ± 0.06°C; P = .0001), or group 4 (38.5°C ± 0.2°C; P = .0001). Hind limb function recovery was greater in group 1 (mean Tarlov score, 4.9 ± 0.057) than in group 2 (2.6 ± 0.3; P = .0028), group 3 (2.1 ± 0.34; P = .0088), or group 4 (0.0 ± 0.0; P = .0003).ConclusionsEpidural cooling catheter combined with systemic moderate hypothermia produced additive cooling ability and protected the spinal cord against ischemia in rabbits more effectively than either intervention alone

Demonstration of periodic nanostructure formation with less ablation by double-pulse laser irradiation on titanium

By pairing femtosecond laser pulses (duration ∼40 fs and central wavelength ∼810 nm) at an appropriate time interval, a laser-induced periodic surface structure (LIPSS) is formed with much less ablation than one formed with a single pulse. On a titanium plate, a pair of laser pulses with fluences of 70 and 140 mJ/cm² and a rather large time interval (>10 ps) creates a LIPSS with an interspace of 600 nm, the same as that formed by a single pulse of 210 mJ/cm², while the double pulse ablates only 4 nm, a quarter of the ablation depth of a single pulse

Open-case series of a remote administration and group setting comprehensive behavioral intervention for tics (RG-CBIT): A pilot trial

PurposeThe comprehensive behavioral intervention for tics (CBIT) is the first-line psychotherapeutic treatment for individuals with tic disorders. However, most patients with tic disorders do not have access to CBIT due to different factors including lack of trained therapists, treatment cost, and travel distance. Such barriers are more prominent in non-English speaking countries. Therefore, the current study assessed the preliminary efficacy, feasibility, and acceptability of remotely administered group CBIT (RG-CBIT) in Japan.MethodsThis was an open-case series that adopted the AB design. Three Japanese children aged between 6 and 13 years who were diagnosed with TS were recruited. RG-CBIT was developed based on the published CBIT manual. Videoconference application, slide presentation software, and cloud learning platform were used as appropriate.ResultsThe Yale Global Tic Severity Scale scores of all participants decreased from baseline to post-treatment. That is, the score reduced by an average of 7.0. Regarding feasibility and acceptability, the attendance rate of participants was 100%, and the process measurement items had favorable scores.ConclusionsRG-CBIT had satisfactory efficacy, feasibility, and acceptability. Hence, it could mitigate the barriers for treatment access

Planning of Special Educational Activities through Three Years in High School : A Trial on Organizing Students into Energetic. Voluntary Groups

「生徒自身の手で自律した体育祭を創る」・・・・・・2002年2月2日付けで高校体育祭運営局から提示されたコンセプトである。それより遡ること4ヶ月前の2001年11月,高校生徒会執行部から2002年度「学校祭」基本方針(案)が提出された。その冒頭に次のように謳ってある。「学校祭(文化祭・体育祭)は,本校の伝統的校風である自出・自主・自律の精神を発現する場であり・・・・・・(中略)・・・・・・主体的な学習の場である。(後略)」生徒たちの中には学校行事を「学びの場」として捉え,それを「自律的に」運営していこうという意識がある。これは今に始まったことではなく,長年本校で培われてきた精神である。ではそれを支える教職員側の意識・態勢はどうであったのか。本稿は2000年度入学生を受け持った6人の担任団がどの場面で何を学ばせようと意図して「学びの場」としての行事を仕掛けていったのか,その実践の記録である

Organizing Active Learning Models in Science Classes (2)

The purpose of this study is to organize active learning models in science classes. Through classroom practice from elementary school to upper secondary school, we observed the followings: 1) the "reciprocal of internalization and externalization," which means collaborative and cooperative learning, is the key to active learning in science lessons; 2) by creating a "subject skeleton," teachers can gain clarity regarding the promotion of deep learning and organize active learning models in science classes