Journal of the American Chemical SocietyDOI: 10.1021/jacs.0c09433
Hiroki Nagasawa, Takahiko Kagawa, Takuji Noborio, Masakoto Kanezashi, Atsushi Ogata, and Toshinori Tsuru
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Hello. Taking a class on microelectronics. Was trying to find what low k dielectric is used in modern industry. In looking around I found out about SiOF. Is this the material that is used for most circuits at 90nm and below? Thanks!
I debating whether to get the Xperia 1II or the Xperia Pro. I plan on keeping either phone for 4 plus years. Snapdragon 865 introduces a few next gen components such as 5G and LPDDR5 ram, so I have a feeling that these phones can easily last 4-5 years without feeling too slow. (Moore's law curve is flattening, we may not see much improvement over the next couple years in terms of processing power) Seems like 5nm may be coming soon.
So, Question. Do you think the low dielectric constant material used on the Xperia Pro could also enhance 4G reception? (I am aware that the material was meant for 5G optimization)
Reason I ask is because I own an Xperia 1, but due to my location (lots of hills and stuff), my reception averages around 3-4 bars (0-2 at home) without a case on. https://i.imgur.com/430HlbD.jpg So it would be nice to have a device with better reception. Also I'm asking about 4G because my carrier (T-mobile) doesn't support the 5G bands offered on the Xperia 1II and mmWave 5G is available in the city north of me, but not in my city. Pretty much 5G is useless to me at the moment. I assume the Xperia 1II will have similar 4G reception as the Xperia 1, but we won't know for sure until someone can test it.
My goal is to have better 4G reception.
What do you guys think?
I just got a Keychron K1 with low profile Gateron reds. I have Permatex Dielectric Grease and Super Lube Aerosol.
I'm trying to make these linear switches even smoother.
Are these lube safe to use on low profile red switches?
Is there anything I should keep in mind when using these with the mentioned switches?
Journal of the American Chemical SocietyDOI: 10.1021/jacs.0c05161
https://ift.tt/2BLOuFt
I've got a junkyard rescue that I've been using to overland on a budget, and I have been avoiding water crossings so far. The fuel pump in my gas tank is dead, so I did the right thing and installed an in-line fuel pump by wiring a switch directly to the battery and using self-tapping screws to secure it under the car, basically right below the driver's seat. It's served me well for the past 9 months, but the terminal connections on the pump are fully exposed to the elements. I haven't had trouble with rain yet, but I suspect that having the 12v power directly from the battery submerged in water will probably not help the old girl... My buddies all tell me that simply slapping on some dielectric grease (or vaseline) will be enough to waterproof it for a few weeks, possibly longer if I then cover it up with some tape or some rubber tubing. Any thoughts? I'm not intending to turn my car into a submarine, I just want to prevent the fuel pump connectors from shorting out if it gets splashed or submerged, hopefully preventing an embarrassing breakdown in the middle of a crossing
Hello everyone,
As many of us know, capacitors have the ability to release massive amounts of energy in short amounts of time. Their main disadvantage is comparatively low energy density compared to gas or lithium ion batteries.
Now, as I understand it, this limitation comes mainly from electrical breakdown of dielectrics. Above a certain threshold voltage, insulators conduct electricity.
Looking at the periodic table, I see some elements with ridiculously high resistivity. Let's take sulfur as an example.
The electrical resistivity of amorphous sulfur, according to Wikipedia, is 2×10^15 Ω⋅m at 20C.
If I calculate the electrical resistivity for a rough capacitor size (plates 1 mm from each other, and 1cm^2 surface area), my resistance is something like 2×10^16 Ω⋅m.
The capacitance of such a construction, assuming that the permittivity of sulfur is only slightly above that of a vacuum (value <2 for dielectric constant), could be very roughly 1x10^-12 F, or 1pF.
We know that the energy stored in a capacitor is 1/2 the capacitance times the voltage squared.
Let's say that I charge this capacitor to a potential of 1 billion (1x10^9) volts. The calculated value for the energy in this case would be roughly 500kJ.
Now let's go back to the resistance of this capacitor's dielectric. It should be 2x10^16 Ω⋅m. Since Ohm's law tells us that current is voltage divided by resistance, I would expect current going through the capacitor's dielectric to be 5x10^-8 amps. This might not seem like much, but as we multiply it by the voltage to get power, this equates to 50W. Just think about this figure compared to power, however. Assuming that the power drains at a constant rate equal to the rate at maximum charge (which it doesn't, and I don't feel like calculus right now), it should take roughly 10,000 seconds for such a capacitor to drain on it's own. I don't know about you, but I think that such a device would have found practical applications in pulse power systems. As long as we pump it with more than 50W, it is charging. Of course, 1 Billion volts is ridiculous. We would probably stack many layer upon layer of dielectric until the voltage was reasonable for a given amount of energy.
That being said, why are capacitors not typically constructed in this manner? Am I overlooking something in my calculations?
Thanks and all response is very much appreciated,
Reece
Hi everyone,
I'm working on Electromagnetic Wave simulation using the book "Electromagnetic simulation using the FDTD method with Python 3rd Edition" from Houle and Sullivan.
The main objective at the end is to simulate ground penetrating radar acquisitions.
For now, I'm stuck on a exercise that contain important phisycal concepts about wave attenuation in lossy mediums.
It consists on the 1-D FDTD simulation of a sinusoidal Ex (electric field) wave at a frequency of 700 MHz travelling on free space and then hitting a dielectric slab with relative dielectric constant of 4 and electrical conductivity of 0.04 S/m. It hits the slab at the cell number 100.
Notice that in this this simulation the Ex field is multiplied by sqrt(mu0/eps_0) for simplicity of computation.
All code blocs must be runned at once on a Python editor.
""" fd1d_1_5.py: 1D FDTD
Simulation of a sinusoid wave hitting a lossy dielectric
"""
import numpy as np
from math import pi, sin
from matplotlib import pyplot as plt
import scipy.optimize
ke = 200
ex = np.zeros(ke)
hy = np.zeros(ke)
t0 = 40
spread = 12
ddx = 0.01 # Cell size
dt = ddx / (2*3e8) # Time step size
freq_in = 700e6
boundary_low = [0, 0]
boundary_high = [0, 0]
# Create Dielectric Profile
epsz = 8.854e-12
epsilon = 4
sigma = 0.04
ca = np.ones(ke)
cb = np.ones(ke) * 0.5
cb_start = 100
eaf = dt * sigma / (2 * epsz * epsilon)
ca[cb_start:] = (1 - eaf) / (1 + eaf)
cb[cb_start:] = 0.5 / (epsilon * (1 + eaf))
nsteps = 500
# Choosing selected positions (cell number) to record ex for all simulation time
pos = np.linspace(100,170,8,dtype='int')
# Initializing ex_k : matrix to record ex at selected positions
ex_k = np.zeros([nsteps,pos.size])
# Main FDTD Loop
for time_step in range(1, nsteps + 1):
# Calculate the Ex field
for k in range(1, ke):
ex[k] = ca[k] * ex[k] + cb[k] * (hy[k - 1] - hy[k])
# Put a sinusoidal at the low end
pulse = np.exp(-0.5 * ((t0 - time_step) / spread) ** 2)
pulse = sin(2 * pi * freq_in * dt * time_step)
ex[5] = pulse + ex[5]
# Absorbing Boundary Conditions
ex[0] = boundary_low.pop(0)
boundary_low.append(ex[1])
ex[ke - 1] = boundary_high.pop(0)
boundary_high.append(ex[ke - 2])
I have some spare Permatex 22058 dielectric grease, can I use it to lubricate my zrod?
Why YSK: Dielectric grease is an insulator, meaning it does not allow electric current to flow through it. If you apply it to the metal electrical contact surfaces inside a plug, you are making it more difficult for the current to flow through that connection.
The grease has many applications and benefits, but the most common use that people are likely familiar with is for vehicle headlights and spark plugs. You know, that little packet of white grease they upsell you at the counter when you buy those items.
The way you are supposed to use it is to apply it around the mating surfaces of the plug/socket, not on the metal electrical contact surfaces. Its purpose is to keep water from getting inside the connector. Think of it like using caulk to seal an opening.
If you apply it to the metal electrical contact surfaces, you are increasing resistance which can cause the plug to heat up. Even if you have done this in the past and haven't had any issues, don't keep doing it because all it takes is that one time where it doesn't wipe enough off and it can cause arcing, the plug to melt, or, wort case scenario, start a fire.
I've replaced more melted headlight plugs than I can count because people unknowingly filled the socket with dielectric grease.
I'm looking at Griffith's Electrodynamics, problem 4.20 (a sphere of linear dielectric material has embedded within it a uniform free charge density.) I solved the potential just fine, but I'm stuck on this one small conceptual point that doesn't really have much to do with the solution itself but is something I was thinking about while working out the math because I like to visualize things in my head.
As far as I know, the total bound charge density should always sum to zero, and since the bound volume charge density in the case of constant P is zero, that must mean that the total surface-bound charge density also equals zero.
Yet, to the best of my knowledge, P is directed radially outward, and so the bound surface charge density of the sphere seems to me, at a glance, to be non-zero.
I know I'm missing something silly. Can someone explain what's wrong with my reasoning?
EDIT: I'm not sure if it matters, but I'm self-studying physics (I took a three-semester college physics course and the required calculus / linear algebra before graduating many years ago and am now trying to continue the journey on my own.)
EDIT 2: Solved! Thank you, u/pinkpanzer101! P is not constant, so there's a divergence that results in a volume bound charge density that cancels out the surface bound charge.
Sunt destul de nou in comunitatea de tastaturi mecanice custom. Tastatura mea curenta este un rk61 cu switchuri gateron black inks. Imi puteti recomanda un loc de unde il pot comanda online sau fizic?
Decomposition of CHF3 by a Dielectric Barrier Discharge Reactor Duc Ba Nguyen and Won Gyu Lee* Oxidation of CHF3 was investigated in a dielectric barrier discharge reactor was immersed in.
So, I'm looking at making some boards that are designed to operate with up to 6 GHz RF signals. Now, I know that FR-4 is generally not recommended for long runs at 6 GHz, but the losses are not excessive for short runs (<2 in) with decent quality FR-4. But the losses are only manageable if they are consistent across batches made potentially months apart.
I'm not sure if anyone has bothered testing the dielectric constant of the boards that low-cost manufacturers have made. Ideally, I'm looking to keep an order of 5, 4x4 in. boards under $100 before shipping.
If anyone has any recommendations or better yet, data, please let me know.
Decided to give it a try and curious who else does the same.
