Factors influencing the start of development in Daphnia pulex winter eggs [Translation from: Biological Reviews Vol. 13, 24-26, 1951]

The winter eggs of Daphnia pulex, after passing safely through the winter , develop and hatch in the spring, multiplying by themselves, while some males emerging among them with the changes in environment produce fertile eggs, which are universally known as winter eggs . This study researches the factors governing the development of winter eggs through experiments

Co-integration of Silicon Nanodevices and NEMS for Advanced Information Processing (Invited Talk)

In this paper we present our recent attempts at developing the advanced information processing devices by integrating nano-electro-mechanical (NEM)structures into conventional silicon nanodevices. Firstly, we show high-speed and nonvolatile NEM memory which features a mechanically-bistable floating gate is integrated onto MOSFETs. Secondly we discuss hybrid systems of single-electron transistors and NEM structures for exploring new switching principles

Precise control of hydrogen response of semicontinuous palladium film using piezoelectric resonance method

During deposition of metallic material on a substrate, a semicontinuous film composed of isolated and connected clusters is formed transiently at a few nanometers thickness. The surface electrical conductivity at this moment is governed by the tunneling conduction, and slight subsequent evolution of the film morphology changes the conductivity markedly because of the island connection. When the semicontinuous palladium film is exposed to hydrogen, its morphology changes because of absorption of hydrogen, changing the surface conductivity drastically. This phenomenon is applicable for hydrogen sensing. However, it has been significantly difficult to fabricate an optimum semicontinuous structure because it appears in a very short time during deposition. In the present study, we precisely control the palladium film morphology using the piezoelectric resonance method. In this method, an electric field is excited around the substrate surface using the resonant vibration of the piezoelectric material. The electric field generates the electrical current in the deposited material, and the vibrational energy of the piezoelectric material is spent on it. Because the energy loss depends on the electrical conductivity (morphology) of the deposited material, by measuring the change in the attenuation of the resonant vibration, evolution of the morphology is detectable. Using this method, palladium films with several morphologies were fabricated, and the conductivity change in hydrogen was evaluated. The change ratio of the conductivity significantly depended on the morphology, and the conductive sensitivity to the hydrogen detection with the optimum structure was larger than that reported in the previous study by a factor of 12.Nakamura N., Ueno T., Ogi H. Precise control of hydrogen response of semicontinuous palladium film using piezoelectric resonance method. Applied Physics Letters, 114(20), 201901 (2019) https://doi.org/10.1063/1.5094917.https://doi.org/10.1063/1.509491

Analisis dan Pengembangan Sistem Manajemen Pengetahuan Berbasis Perangkat Lunak Open Source (Studi Kasus)

Penelitian ini akan memaparkan proses identifikasi dan kategorisasi pengetahuan yang di miliki oleh PT XYZ sebagai objek penelitian, dimana Perusahaan ini membutuhkan wadah yang mendukung sharing knowledge untuk pendokumentasian dan pendistribusian pengetahuan yang ada pada Perusahaan tersebut, serta menerapkan sistem open source untuk mengelola pengetahuan secara mandiri dan terpusat. Metode penelitian yang dilakukan adalah dengan Inukshuk KM Model. Metode pengumpulan data yang digunakan adalah wawancara dan observasi. Hasil yang dicapai dari penelitian ini adalah tersedianya wadah untuk menyimpan dan mengelola pengetahuan yang mudah diakses oleh pengguna. Dengan pengimplementasian sistem manajemen pengetahuan ini diharapkan dapat meningkatan kualitas sharing knowledge antar karyawan, serta meningkatan kualitas knowledge content yang terdapat didalam Perusahaan

Temperature behavior of sound velocity of fluorine-doped vitreous silica thin films studied by picosecond ultrasonics

Vitreous silica (v-SiO2) shows anomalous temperature dependence of velocity, including positive temperature coefficient of velocity (TCV) and velocity minimum around 70 K. The former characteristic allows its application in acoustic-resonator devices as a temperature compensating material. In this paper, we study the temperature dependence of velocity of fluorine-doped v-SiO2 (v-SiO2-xFx) thin films using picosecond ultrasonic spectroscopy. To correct the temperature increase caused by irradiation with light pulses, we calculated the steady temperature increase in the measuring volume with a finite volume method, considering the temperature dependence of thermal conductivity, and find that temperature in the measurement region remains high even when the back surface is cryogenically cooled. Using the corrected temperature, we determine TCV of v-SiO2-xFx thin films for 0 < x < 0.264, which increases as x increases and is smaller than reported bulk values by a factor of 0.5 - 0.7. The velocity minimum is absent for the film with x = 0, but it is clearly observed at 70 K for the film with the highest fluorine concentration of x = 0.264. These temperature behaviors are attributed to the change in the Si-O-Si bond angle caused by the fluorine doping.Nagakubo A., Ogi H., Ishida H., et al. Temperature behavior of sound velocity of fluorine-doped vitreous silica thin films studied by picosecond ultrasonics. Journal of Applied Physics, 118(1), 014307 (2015) https://doi.org/10.1063/1.4923353.https://doi.org/10.1063/1.492335

Optical Phonon Lasing in Semiconductor Double Quantum Dots

We propose optical phonon lasing for a double quantum dot (DQD) fabricated in a semiconductor substrate. We show that the DQD is weakly coupled to only two LO phonon modes that act as a natural cavity. The lasing occurs for pumping the DQD via electronic tunneling at rates much higher than the phonon decay rate, whereas an antibunching of phonon emission is observed in the opposite regime of slow tunneling. Both effects disappear with an effective thermalization induced by the Franck-Condon effect in a DQD fabricated in a carbon nanotube with a strong electron-phonon coupling.Comment: 8 pages, 4 figure