Detecting weak modes in rectangular quartz plates by measuring surface charges

2003 ◽  
Author(s):  
Y. Watanabe ◽  
T. Tanaka ◽  
S. Goka ◽  
H. Sekimoto
Keyword(s):  
Surface Charges ◽  
Measuring Surface

Detecting Spurious Modes in Quartz Plates by Measuring Surface Charges

1999 ◽  
Vol 38 (Part 1, No. 5B) ◽  
pp. 3213-3216
Author(s):  
Yasuaki Watanabe ◽  
Tomohiko Tanaka ◽  
Shigeyoshi Goka ◽  
Hitoshi Sekimoto
Keyword(s):  
Surface Charges ◽  
Measuring Surface ◽  
Spurious Modes

ELECTROHYDRODYNAMIC INSTABILITY OF LIQUID SHEET SATURATING POROUS MEDIUM WITH INTERFACIAL SURFACE CHARGES

2013 ◽  
Vol 23 (2) ◽  
pp. 165-191
Author(s):  
Mohamed F. El-Sayed ◽  
M. H. M. Moussa ◽  
Ahmed A. A. Hassan ◽  
N. M. Hafez
Keyword(s):  
Porous Medium ◽  
Liquid Sheet ◽  
Surface Charges ◽  
Electrohydrodynamic Instability ◽  
Interfacial Surface

Case Studies in Atomic Force Probe Analysis

2006 ◽  
Author(s):  
Randal Mulder ◽  
Sam Subramanian ◽  
Tony Chrastecky
Keyword(s):  
Failure Analysis ◽  
Case Studies ◽  
Light Emission ◽  
Electrical Characterization ◽  
Logic Circuits ◽  
Contrast Imaging ◽  
Atomic Force ◽  
Measuring Surface ◽  
Analysis Environment

Abstract The use of atomic force probe (AFP) analysis in the analysis of semiconductor devices is expanding from its initial purpose of solely characterizing CMOS transistors at the contact level with a parametric analyzer. Other uses found for the AFP include the full electrical characterization of failing SRAM bit cells, current contrast imaging of SOI transistors, measuring surface roughness, the probing of metallization layers to measure leakages, and use with other tools, such as light emission, to quickly localize and identify defects in logic circuits. This paper presents several case studies in regards to these activities and their results. These case studies demonstrate the versatility of the AFP. The needs and demands of the failure analysis environment have quickly expanded its use. These expanded capabilities make the AFP more valuable for the failure analysis community.

Carboxymethyl-hexanoyl Chitosan Nanodroplets for Ultrasonic Imaging and Drug Delivery to Tumor

2018 ◽  
Vol 24 (15) ◽  
pp. 1682-1688 ◽  
Author(s):  
Yu Jinsui ◽  
Situ Bing ◽  
Luo Muhua ◽  
Li Yue ◽  
Liao Jianyi ◽  
...  
Keyword(s):  
Ultrasound Imaging ◽  
Tumor Therapy ◽  
Carboxymethyl Chitosan ◽  
Great Promise ◽  
Ovarian Cancer Cells ◽  
Mechanical Index ◽  
Surface Charges ◽  
Particle Structure ◽  
Drug Release Profile ◽  
Hexanoyl Chitosan

Introduction: Although a great many strategies have been proposed for tumor-targeted chemotherapy, current delivery methods of anticancer drugs present limited success with inevitable systemic toxicity. The aim of this study was to develop a new kind of theranostic carrier for targeted tumor therapy. Methods: Prior to prepare CHC-PFP-DOX, carboxymethyl-hexanoyl chitosan (CHC) was synthesized by acylation of carboxymethyl chitosan. To develop CHC-PFP, perfluoropentane (PFP), an ultrasound gas precursor, was simultaneously encapsulated into the hydrophobic inner cores of pre-formulated CHC micelle in aqueous phase via using the oil in water (O/W) emulsion method. The size distribution and surface charges of these nanodroplets were measured and the morphology was observed by transmission electron microscopy (TEM). For ultrasound imaging application, in vitro model was established to evaluate the imaging of CHC-PFP-DOX under different concentration and mechanical index. After that, the anti-tumor effect of ultrasound combined with CHC-PFPDOX on ovarian cancer cells was investigated. Results: The resulting CHC-PFP-DOX had a nano-sized particle structure, with hydrophobic anticancer DOX/PFP inner cores and a hydrophilic carboxymethyl chitosan polymer outer shell. The favorable nano-scaled size offers the potential to extravagate from veins and accumulate in tumor tissues via enhanced permeation and retention (EPR) effect. Additionally, CHC-PFP-DOX showed the ability to serve as ultrasound imaging agent at body temperature. Notably, it exhibited an ultrasound-triggered drug release profile through the external ultrasound irradiation. Further study demonstrated that ultrasound combined with CHC-PFP-DOX can improve the killing effect of chemotherapy for tumor. Conclusion: CHC-PFP-DOX holds great promise in simultaneous cancer-targeting ultrasound imaging and ultrasound- mediated delivery for cancer chemotherapy.

Evaluation of Surface-modified Superparamagnetic Iron Oxide Nanoparticles to Optimize Bacterial Immobilization for Bio-separation with the Least Inhibitory Effect on Microorganism Activity

2020 ◽  
Vol 10 (2) ◽  
pp. 166-174
Author(s):  
Mehdi Khoshneviszadeh ◽  
Sarah Zargarnezhad ◽  
Younes Ghasemi ◽  
Ahmad Gholami
Keyword(s):  
Iron Oxide ◽  
Amino Acid ◽  
Magnetic Nanoparticles ◽  
Iron Oxide Nanoparticles ◽  
Surface Coating ◽  
Superparamagnetic Iron Oxide ◽  
Superparamagnetic Iron Oxide Nanoparticles ◽  
Oxide Nanoparticles ◽  
Surface Charges ◽  
Surface Modified

Background: Magnetic cell immobilization has been introduced as a novel, facile and highly efficient approach for cell separation. A stable attachment between bacterial cell wall with superparamagnetic iron oxide nanoparticles (SPIONs) would enable the microorganisms to be affected by an outer magnetic field. At high concentrations, SPIONs produce reactive oxygen species in cytoplasm, which induce apoptosis or necrosis in microorganisms. Choosing a proper surface coating could cover the defects and increase the efficiency. Methods: In this study, asparagine, APTES, lipo-amino acid and PEG surface modified SPIONs was synthesized by co-precipitation method and characterized by FTIR, TEM, VSM, XRD, DLS techniques. Then, their protective effects against four Gram-positive and Gram-negative bacterial strains including Enterococcus faecalis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa were examined through microdilution broth and compared to naked SPION. Results: The evaluation of characterization results showed that functionalization of magnetic nanoparticles could change their MS value, size and surface charges. Also, the microbial analysis revealed that lipo-amino acid coated magnetic nanoparticles has the least adverse effect on microbial strain among tested SPIONs. Conclusion: This study showed lipo-amino acid could be considered as the most protective and even promotive surface coating, which is explained by its optimizing effect on cell penetration and negligible reductive effects on magnetic properties of SPIONs. lipo-amino acid coated magnetic nanoparticles could be used in microbial biotechnology and industrial microbiology.

scholarly journals Mechanistic Study on Facet-Dependent Deposition of Metal Nanoparticles on Decahedral-Shaped Anatase Titania Photocatalyst Particles

Catalysts ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 542 ◽  
Author(s):  
Kenta Kobayashi ◽  
Mai Takashima ◽  
Mai Takase ◽  
Bunsho Ohtani
Keyword(s):  
Mechanistic Study ◽  
Phase Reaction ◽  
Surface Charges ◽  
Platinum Nanoparticle ◽  
Nanoparticle Deposition ◽  
Selective Reaction ◽  
Anatase Titania ◽  
Deposition Density ◽  
Titania Photocatalyst ◽  
Source Materials

Facet-selective gold or platinum-nanoparticle deposition on decahedral-shaped anatase titania particles (DAPs) exposing {001} and {101} facets via photodeposition (PD) from metal-complex sources was reexamined using DAPs prepared with gas-phase reaction of titanium (IV) chloride and oxygen by quantitatively evaluating the area deposition density on {001} and {101} and comparing with the results of deposition from colloidal metal particles in the dark (CDD) or under photoirradiation (CDL). The observed facet selectivity, more or less {101} preferable, depended mainly on pH of the reaction suspensions and was almost non-selective at low pH regardless of the deposition method, PD or CDL, and the metal-source materials. Based on the results, the present authors propose that facet selectivity is attributable to surface charges (zeta potential) depending on the kind of facets, {001} and {101}, and pH of the reaction mixture and that this concept can explain the observed facet selectivity and possibly the reported facet selectivity without taking into account facet-selective reaction of photoexcited electrons and positive holes on {101} and {001} facets, respectively.

Gold nanoparticles decorated with oligo(ethylene glycol) thiols: Surface charges and interactions with proteins in solution

2014 ◽  
Vol 426 ◽  
pp. 31-38 ◽  
Author(s):  
Moritz Schollbach ◽  
Fajun Zhang ◽  
Felix Roosen-Runge ◽  
Maximilian W.A. Skoda ◽  
Robert M.J. Jacobs ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Ethylene Glycol ◽  
Surface Charges

scholarly journals Germanium Nanowires as Sensing Devices: Modelization of Electrical Properties

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 507
Author(s):  
Luca Seravalli ◽  
Claudio Ferrari ◽  
Matteo Bosi
Keyword(s):  
Charge Transfer ◽  
Electrical Properties ◽  
Surface Charges ◽  
Molecular Sensing ◽  
Germanium Nanowires ◽  
Physical Mechanisms ◽  
Additional Doping ◽  
Different Types ◽  
N Doping ◽  
Very High

In this paper, we model the electrical properties of germanium nanowires with a particular focus on physical mechanisms of electrical molecular sensing. We use the Tibercad software to solve the drift-diffusion equations in 3D and we validate the model against experimental data, considering a p-doped nanowire with surface traps. We simulate three different types of interactions: (1) Passivation of surface traps; (2) Additional surface charges; (3) Charge transfer from molecules to nanowires. By analyzing simulated I–V characteristics, we observe that: (i) the largest change in current occurs with negative charges on the surfaces; (ii) charge transfer provides relevant current changes only for very high values of additional doping; (iii) for certain values of additional n-doping ambipolar currents could be obtained. The results of these simulations highlight the complexity of the molecular sensing mechanism in nanowires, that depends not only on the NW parameters but also on the properties of the molecules. We expect that these findings will be valuable to extend the knowledge of molecular sensing by germanium nanowires, a fundamental step to develop novel sensors based on these nanostructures.

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