A 2D Chamber-Free Micro Droplet Generator Array Controlled by Dynamic Virtual Walls

2009 ◽  
Author(s):  
Yen-Liang Lin ◽  
Fan-gang Tseng
Keyword(s):  
High Frequency ◽  
Chamber Wall ◽  
Droplet Generator ◽  
Bubble Generation ◽  
Sequential Control ◽  
Wall Structures ◽  
Specific Configuration ◽  
Precise Time ◽  
2D Array ◽  
Dry Film

This paper presents an innovative micro droplet generator array controlled by dynamic virtual walls. The heaters for bubble generation can be arranged into a dense two-dimensional (2D) array by removing the chamber wall structures. The micro droplet generator array was fabricated by heater lithography and direct nozzle formation on a laminated SU-8 dry film without any solid chamber wall among heaters. With precise time-delayed control among microheaters, droplets could be ejected out by the thrust generated from the bubbles around the ejection site under the specific configuration. The volume of the droplet was about 3.8 pL and the initial speed can approach 15 m/s, meeting the standard of commercial printheads. In addition, we carried out the meniscus control by precise sequential control of bubble generations, so the micro droplet generator is free of satellite droplets throughout the whole traveling distance. It showed that the meniscus undergoes a “push-pull-push” progress which can effectively cut the liquid column short. To summarize, a 330 dpi chamber-free micro droplet generator prototype has been realized, and it has the potential for the application to large 2D format, high frequency, high resolution printing.

Advanced Low Df Dry film Build-up Material on Glass panel for 5G application

2020 ◽  
Vol 2020 (1) ◽  
pp. 000201-000205
Author(s):  
Takenori Kakutani ◽  
Zhong Guan ◽  
Yuya Suzuki ◽  
Muhammad Ali ◽  
Serhat Erdogan ◽  
...  
Keyword(s):  
High Frequency ◽  
Transmission Loss ◽  
Core Material ◽  
Wave Band ◽  
Organic Substrates ◽  
Frequency Filter ◽  
Transmission Characteristics ◽  
Glass Panel ◽  
Low Loss ◽  
Dry Film

Abstract This paper describes the demonstration of a low loss substrate (laminated glass) for high-frequency transmission using a dry film build-up material with low loss tangent (Df). This paper also evaluates filter characteristics and dielectric characteristics of the substrate in the mm-Wave band. The advanced low loss dry film build-up material was newly developed, and applicable to high frequency transmission. This material has a Df of 0.0025 at 10 GHz and also exhibits excellent adhesion and electrical reliability required for advanced dielectric materials. In addition, glass was used as a core material in this paper because of its excellent signal transmission characteristics compared to silicon wafers or organic substrates. To demonstrate the benefit of low loss materials for high frequency transmission, passive components for high frequency filter substrates were fabricated using - 6-inch square thin (0.2mm) glass panel with various build-up materials (Material A with a Df of 0.0025, and Material B with a Df 0.0042 at 10 GHz) laminated. Copper wiring patterns on the dielectric layers were fabricated by a semi-additive process (SAP). Circuit patterns with low pass filters and band pass filters were also fabricated. First, transmission characteristics and characteristic impedances were measured to check the electrical performance. The measured lowest transmission loss of < 1.43 dB at 39 GHz were achieved when Material A was applied as the build-up material. Second, biased-highly accelerated stress test (bHAST) was conducted to evaluate the reliability performance of the substrates with two build-up materials, Material A and a conventional material. The test condition was based on the JEDEC level 2 standard. The substrate with Material A retained good insulation properties over 300 hours of bHAST treatment, demonstrating its excellent insulating performance. In summary, Material A has been shown in this paper to exhibit reduced transmission loss in high-frequency filter substrates at millimeter wave frequencies.

The Design and Realization of Micro Induction Heater for the Thermal Bubble Generation

2014 ◽  
Vol 609-610 ◽  
pp. 1239-1247
Author(s):  
Yue Peng Hou ◽  
Ben Dong Liu ◽  
Jia Hui Yang ◽  
Ping Cai
Keyword(s):  
High Frequency ◽  
Heating Effect ◽  
Bubble Generation ◽  
Induction Heater ◽  
Ac Power ◽  
Eddy Current Effect ◽  
Micro Pump ◽  
Heater Core ◽  
Power Frequency ◽  
Frequency Current

This paper presents a micro induction heater based on the principle of induction heating. The liquid contact with the micro heater core directly and heated by the eddy current effect. The heating effect of the micro heater is simulated with the software of COMSOL. The simulation results indicate that the temperature of the micro heater core can reach to 540K in 0.9s while the current is 0.7A and the power frequency is 200 kHz. The relations between the heating effect and the micro induction heaters parameters such as the current, the AC power frequency and the coils parameters are studied in the simulation respectively. The prototype of the micro heater has been fabricated and the experimental test has carried with the micro heater. The experiments indicated that the micro heater can generate thermal bubble in 0.3s while the 1.0A high frequency current passes through the heater coil. The micro induction heater can be applied to a variety of thermal bubble devices, such as micro injector, micro switch and micro pump.

scholarly journals High-frequency switching in Candida albicans.

1992 ◽  
Vol 5 (2) ◽  
pp. 183-203 ◽  
Author(s):  
D R Soll
Keyword(s):  
Candida Albicans ◽  
High Frequency ◽  
Molecular Mechanisms ◽  
Phenotypic Variability ◽  
Epigenetic Mechanism ◽  
Cell Phenotype ◽  
Wall Structures ◽  
Specific Antigens ◽  
Unique Cell ◽  
System Switching

Most strains of Candida albicans are capable of switching frequently and reversibly between a number of phenotypes distinguishable by colony morphology. A number of different switching systems have been defined according to the limited set of phenotypes in each switching repertoire, and each strain appears to possess a single system. Switching can affect many aspects of cellular physiology and morphology and appears to be a second level of phenotypic variability superimposed upon the bud-hypha transition. The most dramatic switching system so far identified is the "white-opaque transition." This system dramatizes the extraordinary effects switching can have on the budding cell phenotype, including the synthesis of opaque-specific antigens, the expression of white-specific and opaque-specific genes, and the genesis of unique cell wall structures. Switching has been demonstrated to occur at sites of infection and between episodes of recurrent vaginitis, and it may function to generate variability in commensal and infecting populations for adaptive reasons. Although the molecular mechanisms involved in the switch event are not understood, recent approaches to its elucidation are discussed and an epigenetic mechanism is proposed.

scholarly journals Development of Broadband High-Frequency Piezoelectric Micromachined Ultrasonic Transducer Array

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1823
Author(s):  
Xu-Bo Wang ◽  
Le-Ming He ◽  
You-Cao Ma ◽  
Wen-Juan Liu ◽  
Wei-Jiang Xu ◽  
...  
Keyword(s):  
High Frequency ◽  
3D Imaging ◽  
Ultrasonic Transducer ◽  
Ultrasonic Transducers ◽  
Frequency Bandwidth ◽  
Half Wavelength ◽  
Acoustic Beams ◽  
Working Frequency ◽  
Sub Wavelength ◽  
2D Array

Piezoelectric micromachined ultrasonic transducers (PMUT) are promising elements to fabricate a two-dimensional (2D) array with a pitch small enough (approximately half wavelength) to form and receive arbitrary acoustic beams for medical imaging. However, PMUT arrays have so far failed to combine the wide, high-frequency bandwidth needed to achieve a high axial resolution. In this paper, a polydimethylsiloxane (PDMS) backing structure is introduced into the PMUTs to improve the device bandwidth while keeping a sub-wavelength (λ) pitch. We implement this backing on a 16 × 8 array with 75 µm pitch (3λ/4) with a 15 MHz working frequency. Adding the backing nearly doubles the bandwidth to 92% (−6 dB) and has little influence on the impulse response sensitivity. By widening the transducer bandwidth, this backing may enable using PMUT ultrasonic arrays for high-resolution 3D imaging.

The Effects of Driving Waveform and Frequency on the Droplet Formation Process

2007 ◽  
Author(s):  
G. Yang ◽  
J. A. Liburdy
Keyword(s):  
Formation Process ◽  
High Frequency ◽  
Droplet Formation ◽  
Driving Frequency ◽  
Droplet Generator ◽  
Frequency Dependent ◽  
Frequency Regime ◽  
Lumped Element Model ◽  
Driving Waveform ◽  
Liquid Filament

For a piezoelectric stack (PZT) driven droplet generator, the driving waveform and driving frequency effects on liquid filament shape and droplet characteristics have been studied. A lumped element model (LEM) is developed to study the acoustic-mechanical behavior and the volumetric rejection of the droplet generator. Based on the LEM, the PZT displacement magnitude dominates the internal pressure variation within the chamber. However due to the natural response of droplet generator, the acoustic pressure in the droplet generator decays exponentially. Experimental data show that the droplet formation process can be waveform and frequency dependent. When the droplet formation process is driven in the “low frequency” regime, the droplet formation process is weakly affected by frequency. Meniscus interaction effects, which are the interaction of a liquid filament from different droplet generation cycles, on the droplet formation process will be present when the droplet formation process is driven in the “high frequency” regime. Due to meniscus interactions, the droplet formation process at “high frequency” is waveform and frequency dependent. Results show that the droplet volume reduces with driving frequency, and droplet velocity increases with driving frequency. However the droplet break-off time is only weakly affected by the driving frequency.

Temperature Dependence of Magnetic Domains and Wall Structures

1972 ◽  
Vol 30 ◽  
pp. 496-497
Author(s):  
Sonoko Tsukahara ◽  
Tadami Taoka ◽  
Hisao Nishizawa
Keyword(s):  
Temperature Dependence ◽  
Domain Walls ◽  
Magnetic Domain ◽  
Iron Film ◽  
Objective Lens ◽  
Lorentz Microscopy ◽  
Domain Structures ◽  
Wall Structures ◽  
Crystal Films ◽  
Metallurgical Structure

The high voltage Lorentz microscopy was successfully used to observe changes with temperature; of domain structures and metallurgical structures in an iron film set on the hot stage combined with a goniometer. The microscope used was the JEM-1000 EM which was operated with the objective lens current cut off to eliminate the magnetic field in the specimen position. Single crystal films with an (001) plane were prepared by the epitaxial growth of evaporated iron on a cleaved (001) plane of a rocksalt substrate. They had a uniform thickness from 1000 to 7000 Å.The figure shows the temperature dependence of magnetic domain structure with its corresponding deflection pattern and metallurgical structure observed in a 4500 Å iron film. In general, with increase of temperature, the straight domain walls decrease in their width (at 400°C), curve in an iregular shape (600°C) and then vanish (790°C). The ripple structures with cross-tie walls are observed below the Curie temperature.

Ruthenium red and alcian blue effects on outer structures of methanotrophic bacteria

1988 ◽  
Vol 46 ◽  
pp. 72-73
Author(s):  
T.A. Fassel ◽  
M.J. Schaller ◽  
C.C. Remsen
Keyword(s):  
Research Effort ◽  
Ruthenium Red ◽  
Outer Cell ◽  
Methanotrophic Bacteria ◽  
En Bloc ◽  
Methylosinus Trichosporium ◽  
Wall Structures ◽  
Methylomonas Albus ◽  
Type Strains ◽  
Outer Cell Wall

Methane, a contributor to the “greenhouse effect”, is oxidized in the natural environment by methanotrophic bacteria. As part of a comprehensive research effort, we have been examining the ultrastructure of methanotrophs. These microorganisms have complex outer cell wall structures similar to those frequently found in other chemol itho- trophic bacteria. (1,2)In our work, we have focused on the “type” strains of Methylomonas albus BG8 and Methylosinus trichosporium OB3b. Between Spurr and LR White embedding resins, we found a difference 1n the preservation of an outer cup layer of BG8 external to the peripheral membranes. Cells from the same sample embedded in Spurr consistently lacked this feature (FIG. 1). This effect was overcome by an en bloc ruthenium red (RR) protocol that resulted in successful retention of the cup layer in Spurr resin (FIG. 2). For OB3b cells, the en bloc RR protocol resulted in an exterior bead feature distinguishable in thin section (FIG. 4) that previously was seen only by SEM.

Architecture of Radiolitid Rudist (Mollusca) Shell-Wall Structures and its Phylogenetic Implications

1975 ◽  
Vol 33 ◽  
pp. 686-687
Author(s):  
David H. Sturm ◽  
Bob F. Perkins
Keyword(s):  
Phylogenetic Relationships ◽  
Outer Wall ◽  
Shell Microstructure ◽  
Shell Wall ◽  
Wall Structures ◽  
Phylogenetic Implications ◽  
Cellular Wall ◽  
Superfamily Analysis ◽  
Central Texas

Each of the seven families of rudists (Mollusca, Bivalvia, Hippuritacea) is characterized by distinctive shell-wall architectures which reflect phylogenetic relationships within the superfamily. Analysis of the complex, calcareous, cellular wall of the attached valve of the radiolite rudist Eoradiolites davidsoni (Hill) from the Comanche Cretaceous of Central Texas indicates that its wall architecture is an elaboration of the simpler monopleurid rudist wall and supports possible radiolite-monopleurid relationships.Several well-preserved specimens of E. davidsoni were sectioned, polished, etched, and carbon and gold coated for SEM examination. Maximum shell microstructure detail was displayed by etching with a 0.7% HC1 solution from 80 to 100 seconds.The shell of E. davidsoni comprises a large, thick-walled, conical, attached valve (AV) and a small, very thin, operculate, free valve (FV) (Fig. 1a). The AV shell is two-layered with a thin inner wall, in which original structures are usually obliterated by recrystallization, and a thick, cellular, outer wall.

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