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Getting To Columbia April 23, 2012

Posted by peterxu422 in education, Science.
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I avoid talking about myself on this blog unless it pertains to a personal experience with the scientific topic of discussion. But in lieu of recent events, I wanted to make an exception. A few days ago, I heard back from Columbia University informing me that I was accepted to their 3-2 Engineering Program. It is a joint program with certain liberal arts colleges where potential students spend three years in their home institution earning a B.A. and two years at Columbia earning a B.S. in a particular field of engineering. Students have to meet the requirements for graduation, meet the engineering course requirements, complete a major, and maintain a 3.0 GPA during their time at their home institution.

I began to seriously consider a career in engineering during my final year of high school. It started with seeing the movie Iron Man in theaters. Seeing the power of the technology and the work Tony Stark put into building it captivated my imagination and piqued my curiosity. I tried to start thinking more like an engineer and put more effort into solving problems in my classes.

But when I came to Queens College, a liberal arts school, engineering was not available. I was ready to go into Computer Science instead. Not long after, a fellow classmate told me about an engineering program that was offered by the Physics Department. I rushed to find out more and learned that this was a joint 5-year program with Columbia University. After speaking to the liaison, I learned that most students who did this program were physics majors because a lot of the courses overlapped between the Physics Department and the engineering requirements. He laid out a preliminary schedule of courses that he recommended I should take within the next three years to complete the program. It was booked with a heavy set of physics and math courses.

Physics was actually one of my weaker subjects in high school. Including the regents, I mostly scored in the low 80s. I did not think I would do well in the major unless I became interested in the subject itself. So that’s what I did. I read up on many articles and watched documentaries every week on the field to learn about the history of the subject as well as recent developments. I was fascinated and I loved it. It made taking the classes a lot easier and more pleasant. Rather than seeing my science courses as something I had to drag myself through, they became the fine tuners of the details of the bigger picture in which I saw science.

Though the 3-2 program guarantees admission to whoever meets all the requirements, it does not mean it’s a shoo-in program. To give this some perspective, the program has 150 seats available. According to QC’s liaison, the number of interested applicants from our school alone would fill all of those seats. But the actual number of students who get accepted from our school each year is on average five. From my perspective, doing well in the classes is not even the biggest challenge. The most difficult part is completing all of the necessary requirements within the allotted time. By the second semester, you would start to have on average 3-4 science and math classes per semester.

That can be something to fear or to look forward to depending on your mindset. If you are really genuinely interested in the field, what’s so terrible about learning more about the things you like? What I learned most from this program, aside from the wealth of technical knowledge, is that genuine interest and curiosity are much stronger mentalities and get you much further than rigid perseverance alone. You can keep telling yourself “just 3, 5, 10, or 20 more years of this and I’ll finally get what I’ve been waiting for.” If you’re only living for a reward, you don’t get to experience the path that gets you there, which can often be rewarding itself. Or worse, you set yourself up for greater disappointment should you fail in your endeavors. But if you can live with a curiosity and eagerness to learn about a particular field, I think you’ll be blessed with joy and satisfaction at any point in your life. Be a geek about something and good things will happen.

Engineering At The Nanoscale April 14, 2012

Posted by peterxu422 in Science, Technology.
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Devices keep getting smaller. Objects that once were only seen with the naked eye now can be looked at through a microscope. How do we keep putting more stuff in less space?

Building technology at the nanoscale, virtually at the atomic level, is the heart of our modern day technological revolution. It seems impossible that engineers can perform such a feat. How do they do it? It turns out some of the techniques used to fabricate at the nanoscale are not as Herculean as one might imagine.

Currently, I work in Dr. Vinod Menon’s Laboratory for Nano and Micro Photonics (LaNMP) at Queens College. The work I do there regularly involves creating structures with very fine thicknesses. For example, I often need to place a layer of material about 400 nm thick on top of a glass piece. The technique I use to accomplish this is called spin coating. There is a device called a spin coater which consists of a rotating platform. I place my glass slide on top of the platform, and use suction to keep it fixed on the mount. I take a liquid solution of my material and place a few drops on top of the glass. The spin coater allows me to adjust the spin speed and spin time. When I let it run, the platform begins to spin rapidly. Because of the centrifugal force caused by the rotation, a lot of the solution flings off the glass slide leaving only a very thin but even layer of material on top of my glass slide that is only nanometers thick. The faster it spins, the thinner it gets. The longer it spins, the thinner it gets.

This week, I went to City College to use one of their devices that allowed me to deposit thin layers of gold on top of a piece of Silicon. The device had an airtight chamber where I placed my samples inside as well as the gold I would be depositing. The gold was held between two metallic fixtures that kept it in place, and the Silicon pieces were laid underneath. The air is sucked out of the chamber to remove any impurities in the process. Because the gold piece is held between two metallic fixtures, I can pass a current through it which would heat up the gold and cause it to vaporize. I raise the current to 50 Amps and the gold piece begins to glow hot. A detector inside displays a reading of how thick the gold layer is and I see that the reading is increasing.

Intel, the largest semiconductor chip making company in the world, also uses special techniques to create their ever increasingly powerful chips. They use a technique called photolithography to fabricate their chips. The way it works is they usually have a base material called a substrate. Then they put a layer of semiconducting material on top of the substrate. This material is sensitive to light, meaning when light is shined on it, it vaporizes. They then put on top of this layer a stencil, that outlines the pattern they want to draw on their chip. Once the stencil is in place, they use light, usually ultraviolet light, to blast away the exposed layers. The parts that are covered by the stencil are kept intact and thus they produce a desired pattern on their chip. They repeat this process with other material as well until they have their completed structure.

There are a number of other techniques that can be used to engineer at the nanoscale. The ones I have mentioned are those that I have been exposed to and had personal experience with. As you can see, building nanoscale structures does not have to involve a very intricate and complicated process. We can use accessible macroscopic techniques to achieve microscopic creations.

Revisiting the Periodic Table April 8, 2012

Posted by peterxu422 in education, Science, Technology.
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This week on the PBS show NOVA, David Pogue, a New York Times tech columnist, hosted a two hour program titled “Hunting The Elements”. Being the funny goofy person that he is, he made the episode very entertaining filled with fascinating science explained. It is definitely worth a watch for those who have Periodic Table phobia, a term I coined describing those who fear or dislike looking at a periodic table because they do not know how to read one. This program would be great medicine for that.

In the episode, he talks about the reactivity of elements, their origins, their uses, and their properties. In one scene, he goes to an explosion range where he and the fellow scientists test out the explosion speeds of different types of explosive materials like gunpowder, nitrate gel, and C4. He explains that how fast a substance explodes depends on how far away oxygen atoms are from each other within the molecules. Things that burn require oxygen, and so if oxygen is closer to the exploding substance, the reaction can occur more quickly and thus the explosion will be faster. Gunpowder was the slowest one because it has oxygen atoms far away. This is why it’s used to fire projectiles because it has enough force to shoot a projectile out but not enough to destroy the barrel of the gun. C4 is the fastest because the molecules that make up C4 have the oxygen atoms packed closely together.

In another sequence, he visits a bell manufacturing company and makes a whole bronze bell with them. He explains that bronze is made from a combination of copper and tin. Copper is malleable. So if a bell was made of copper and it was struck, it would not create a very good sound since the denting would absorb some of the mechanical energy that would have caused the vibrations to create the sound. Adding tin to the mixture fills up some of the gaps between the copper atoms which would restrict their movement. You get a much sturdier material which is very good for making the resonating rings of bells. Pogue then took a sample of the bell’s material to a lab to see if they had a good mixture of tin and copper. At the lab, they used an electron microscope and magnified the sample to such incredible scales that they were looking at the actual atoms themselves. It showed a very ordered layer of dots where the brighter ones were tin atoms while the darker ones were copper.


Electron microscope image of diamond and silicon

The last sequence I’d like to mention was about shark repellent material. Apparently, the lonely bottom two layers of the Periodic Table, the rare earth metals, have some purpose. These elements are supposedly able to repel sharks. The man who demonstrated this made a large powerful magnet out of one type of rare earth element and when he brought it close to a shark, it immediately turned its head away. They do a few other experiments that clearly illustrate the sharks do not like this material. They suspect the reason for this is that the sharks feel an electric shock when in the presence of this material. When they placed the magnet and a shark fin into a beaker of water, and connected two electric wires from a Voltmeter to it, they showed that a current was flowing. The atoms flowing off the magnet would lose their electrons making them positively charged. These positive ions are then attracted to the shark fin and they flow along it. This stream of moving charges creates a current thus giving a small jolt to the shark. However, the problem I see is that this explanation assumes that the magnet is inside the water. But when they brought the magnet close to the shark form the outer wall of the pool, the shark showed the same reaction. There must be more to the story than the explanation of the electric current.

Finally, to further your experience with the periodic table, I recommend downloading the free iPad app inspired by this program called The Elements. Pogue helped design it himself. It has an interactive Periodic Table, a fun molecule building game, and the whole Hunting the Elements program on it. David Pogue will be replacing Neil deGrasse Tyson as host of NOVA Science Now for the time-being. Dr. Tyson is taking time to film a reboot series of “Cosmos” formerly hosted by Carl Sagan. Pogue is an excellent choice for a host. I had the privilege of meeting him once and he is a very kind and funny person.

VIDEO: Preview for Hunting the Elements

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