Sunday, May 2, 2010
Friday, April 16, 2010
Thursday, April 8, 2010
Monday, April 5, 2010
Saturday, March 13, 2010
Friday, February 26, 2010
Reviews of calculations of Ultrasound physics
- Frequency
frequency = Propagation speed (c)/wavelength,
- Period
Period = 1/ frequency
- Wavelength
wavelength = propagation speed/frequency
- Propagation speed
Propagation speed = wavelength * frequency
- Pulse Repetition Period
Pulse repetition period = 1/Pulse repetition frequency
- Duty Factor
duty factor = Pulse duration/Pulse repetition period
duty factor = pulse duration * Pulse repetition frequency/1000
- Spatial Pulse Length
Spatial pulse length = wavelength * number of cycles in a pulse
- Power
Power = amplitude squared
- Intensity
intensity = Power/ area
- Decibels
decibels = 10* log( finanal intensity/initial intensity)
- Half Intensity Depth
half-intensity depth = 3/attenuation coefficient or =6/frequency
- Attenuation coefficient
attenuation coefficient = frequency/2
- Attenuation
attenuation = distance * attenuation coefficient
- Acoustic impedance
Acoustic impedance = density * propagation speed
- Distance to the reflector
distance of the reflector = 0.77 * pulse round-trip time or = pulse round-trip time/13
total traveling distance = 2 * distance of the reflector
- Frequency of active element
frequency = Propagation speed / 2* thickness
- Axial Resolution
Axial resolution = Spatial pulse length (SPL)/ 2
- Q factor
q factor = frequency/ bandwidth
Thursday, February 25, 2010
Physics quick review 2
Reciprocals or reverse relationships of ultrasound physics
- Frequency and wavelengh
- Frequency and period
- Frequency and value of Q factor
- Frequency and diameter of focus zone
- wavelengh and axial resolution
- Cycles and axial resolution
- Spatial pulse length and axial resolution
- period and axial resolution
- value of Q factor and axial resolution
- Elasticity and Propagation speed
- Compressibility and Impedance
- Area and Amplitude
- Area and Power
- Traveling distance and Amplitude
- Travel distance and power
- Travel distance and Intensity
Proportional relationship
- Frequency and attenuation
- Frequency and axial resolution
- Frequency and lateral resolution
- Frequency and thickness of active element
- Frequency and lateral resolution
- Frequency and distance of focus zone length
- wavelength and Spatial pulse length
- Cycles and spatial pulse length
- Pulse Repetition Frequency and Pulse repetition period
- Pulse Repetition Frequency and depth of reflector
- Pulse repetition Period and depth of reflector
- Stiffness and Propagation speed
- Amplitude and Power
- Amplitude and Intensity
- Power and Intensity
- propagation speed and Impedance
- Density and Impedance
- Travel distance and attenuation
NO relationship
Monday, February 22, 2010
Saturday, February 20, 2010
Thursday, February 18, 2010
Friday, February 12, 2010
Wednesday, February 10, 2010
Quick Review for Mid-term Exam
Think yourself first and then click on the words for further understanding. Hope the best!
mechanical wave Longitudinal wave Acoustic variable
Thursday, February 4, 2010
"Size Does Matter" , the Longer and Stronger, the More Orgasm
There is an old saying " size does matter". Yes, there are lot of experiments and reports that the size and length of man's penis can increase women sexual satisfaction and orgasm. The question is that : can man can increase their size and length without surgery and medication? The answer is absolutely. And furthermore, you can do this with spend a lot of time and money, no any side effect and long lasting effect. It isvery easy to perform whenever you want to.
Let me first explain why penis can get longer and larger just by exercising or stretching. In anatomy, penis is composed largely a muscle tissue, that is same as that in the arm and legs. We know many people go to gym for strong and big muscle. So the mechanism apply to penis muscle. Secondly, there are lot of vessels around penis. When excited and erected, the vessel in the penis relaxed and more blood go the penis and make penis elongate and widen. The wall of blood vessels is also consisted of muscle tissue, which can be stronger and thicker by streching.
Let me first explain why penis can get longer and larger just by exercising or stretching. In anatomy, penis is composed largely a muscle tissue, that is same as that in the arm and legs. We know many people go to gym for strong and big muscle. So the mechanism apply to penis muscle. Secondly, there are lot of vessels around penis. When excited and erected, the vessel in the penis relaxed and more blood go the penis and make penis elongate and widen. The wall of blood vessels is also consisted of muscle tissue, which can be stronger and thicker by streching.
Hair Loss May Indicate Lack of Enough Sleep
Currently, the exact cause of hair loss is unknown. There are many theories about it. The most common one associate it with the male hormone called testororone. Some of them attribute it to poor blood supply to skin on which the hair is grown. In this article, I will present another common but easy neglected cause for hair loss, lack of sleep.
You may ask why lack of sleep cause hair? To better understand this, we first need to know there are two system that control basic status of body activities. One is called sympathetic nervous system, which is active in the day. the other one is called parasympathetic nervous systems, which is active at night (at sleep). The function of sympathetic nervous system is to participate body's reaction to adverse reaction such as fight. Parasympathetic nervous system take control when body is at sleep. Both of the two system are out of our human voluntary control.The blood vessel of the scalp on which the hair is grown will contract when sympathetic system is active and relax when parasympathetic system is active (such as sleep). So if somebody can get enough sleep, he will definitely will get good blood supply to the scalp and health hair. On the contrary, people with less sleep or lack of sleep will get more hair loss than it should.
So avoid hair loss, here is some advice for those people who suffer from amnesia.
1. Establish good sleep habit. for example, go to bed early and go up early.
2. Participate more exercise
3. Take enough high vitamin containing food
4. Avoid deep night working such as reading and
5. Avoid take a lot of water during night
6. Avoid take hot food at night.
You may ask why lack of sleep cause hair? To better understand this, we first need to know there are two system that control basic status of body activities. One is called sympathetic nervous system, which is active in the day. the other one is called parasympathetic nervous systems, which is active at night (at sleep). The function of sympathetic nervous system is to participate body's reaction to adverse reaction such as fight. Parasympathetic nervous system take control when body is at sleep. Both of the two system are out of our human voluntary control.The blood vessel of the scalp on which the hair is grown will contract when sympathetic system is active and relax when parasympathetic system is active (such as sleep). So if somebody can get enough sleep, he will definitely will get good blood supply to the scalp and health hair. On the contrary, people with less sleep or lack of sleep will get more hair loss than it should.
So avoid hair loss, here is some advice for those people who suffer from amnesia.
1. Establish good sleep habit. for example, go to bed early and go up early.
2. Participate more exercise
3. Take enough high vitamin containing food
4. Avoid deep night working such as reading and
5. Avoid take a lot of water during night
6. Avoid take hot food at night.
Easy bruising is associated with Vitamin C deficiency
Every day, almost everybody have problems with blood. For example, you may bleed when you cut your skin accidentally. For people over 30 years old, you may have gum bleeding when you brush you teeth every day. For some of these problems it may indicate that something wrong in your body.For this reason, it is necessary to pay attention to your blood care stuff when you have some bleeding in your body. The most common problems for normal individuals is iron deficiency which can cause anemia even bleeding. The second most common and easily neglect blood problem is gum bleeding, which is usually caused by Vitamin C deficiency. In women this symptom is usually presented as easy bruising at light exercise when approaching period. This symptom can go away by just taking vitamin C rather than thinking something serious.
Monday, February 1, 2010
Carpal tunnul syndrome in hypothyroidism
Carpal tunnel syndrome is another disorder associated with hypothyroidism. It is caused by enlargement of all tissues passing through a tube structure at your wrist. As result, the nerve innervate your fingers is compressed
and make you feeling of numbness , tingling and in your finger. Some time it cause pain. if paid no attention, it may worsen and need a surgery to relieve compression. At the beginning of the early symptoms, you can do following steps to relieve the sympotom and avoid surgery.
1. Flex and extend your wrist 100 times by holding dumb bell. The weight of the dumb bell depends on individul
wrist strength. Usually start the small weight and increase gradually to maximun weigh you can handle.
2. After exercise, submerge your wrist in a warm water for 30 minutes.
3. Eat high fiber and potassium containing food.
and make you feeling of numbness , tingling and in your finger. Some time it cause pain. if paid no attention, it may worsen and need a surgery to relieve compression. At the beginning of the early symptoms, you can do following steps to relieve the sympotom and avoid surgery.
1. Flex and extend your wrist 100 times by holding dumb bell. The weight of the dumb bell depends on individul
wrist strength. Usually start the small weight and increase gradually to maximun weigh you can handle.
2. After exercise, submerge your wrist in a warm water for 30 minutes.
3. Eat high fiber and potassium containing food.
Sunday, January 31, 2010
Muscle spasm in hypothyroidism
Muscle spasm is a common symptom when hyperthyroidism is changed to hypothyroidism using Radioiodine I-131 therapy in first couple of months. Any strenuous exercise can promote strong, persistent contraction of your muscle. The first step is to check your blood for any electrolytes abnormalities in your blood. Usually it will show low level of calcium and you will increase your calcium intake in your food. If symptom do not go away, this spasm may be caused by low levels of potassium in your blood. Increasing high potassium food will solve this problem.
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