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a day in the library every time. In August of 2006 I did a literature search and found about 300 relevant papers on titanium dioxide. I saw that each of the many different communities researching titanium dioxide had its own way of describing the compound. By the end of the |
month, the pieces had fallen into place. I finally knew how our device worked. I knew why we had a memristor. The exotic molecule monolayer in the middle of our sandwich had nothing to do with the actual switching. Instead, what it did was control the flow of oxygen from |
the platinum dioxide into the titanium to produce the fairly uniform layers of TiO 2 and TiO 2-x . The key to the switching was this bilayer of the two different titanium dioxide species [see diagram, ”How Memristance Works”]. The TiO 2 is electrically insulating (actually a semiconductor), but the |
TiO 2-x is conductive, because its oxygen vacancies are donors of electrons, which makes the vacancies themselves positively charged. The vacancies can be thought of like bubbles in a glass of beer, except that they don’t pop—they can be pushed up and down at will in the titanium dioxide material |
because they are electrically charged. Now I was able to predict the switching polarity of the device. If a positive voltage is applied to the top electrode of the device, it will repel the (also positive) oxygen vacancies in the TiO 2-x layer down into the pure TiO 2 layer. |
That turns the TiO 2 layer into TiO 2-x and makes it conductive, thus turning the device on. A negative voltage has the opposite effect: the vacancies are attracted upward and back out of the TiO 2 , and thus the thickness of the TiO 2 layer increases and the |
device turns off. This switching polarity is what we had been seeing for years but had been unable to explain. On 20 August 2006, I solved the two most important equations of my career—one equation detailing the relationship between current and voltage for this equivalent circuit, and another equation describing |
how the application of the voltage causes the vacancies to move—thereby writing down, for the first time, an equation for memristance in terms of the physical properties of a material. This provided a unique insight. Memristance arises in a semiconductor when both electrons and charged dopants are forced to move |
simultaneously by applying a voltage to the system. The memristance did not actually involve magnetism in this case; the integral over the voltage reflected how far the dopants had moved and thus how much the resistance of the device had changed. We finally had a model we could use to |
engineer our switches, which we had by now positively identified as memristors. Now we could use all the theoretical machinery Chua had created to help us design new circuits with our devices. Triumphantly, I showed the group my results and immediately declared that we had to take the molecule monolayers |
out of our devices. Skeptical after years of false starts and failed hypotheses, my team reminded me that we had run control samples without molecule layers for every device we had ever made and that those devices had never switched. And getting the recipe right turned out to be tricky |
indeed. We needed to find the exact amounts of titanium and oxygen to get the two layers to do their respective jobs. By that point we were all getting impatient. In fact, it took so long to get the first working device that in my discouragement I nearly decided to |
put the molecule layers back in. A month later, it worked. We not only had working devices, but we were also able to improve and change their characteristics at will. But here is the real triumph. The resistance of these devices stayed constant whether we turned off the voltage or |
just read their states (interrogating them with a voltage so small it left the resistance unchanged). The oxygen vacancies didn’t roam around; they remained absolutely immobile until we again applied a positive or negative voltage. That’s memristance: the devices remembered their current history. We had coaxed Chua’s m... |
the page and into being. Emulating the behavior of a single memristor, Chua showed, requires a circuit with at least 15 transistors and other passive elements. The implications are extraordinary: just imagine how many kinds of circuits could be supercharged by replacing a handful of transistors with one single memristo... |
The most obvious benefit is to memories. In its initial state, a crossbar memory has only open switches, and no information is stored. But once you start closing switches, you can store vast amounts of information compactly and efficiently. Because memristors remember their state, they can store data indefinitely, usin... |
energy only when you toggle or read the state of a switch, unlike the capacitors in conventional DRAM, which will lose their stored charge if the power to the chip is turned off. Furthermore, the wires and switches can be made very small: we should eventually get down to a |
width of around 4 nm, and then multiple crossbars could be stacked on top of each other to create a ridiculously high density of stored bits. Greg Snider and I published a paper last year showing that memristors could vastly improve one type of processing circuit, called a field-programmable gate |
array, or FPGA. By replacing several specific transistors with a crossbar of memristors, we showed that the circuit could be shrunk by nearly a factor of 10 in area and improved in terms of its speed relative to power-consumption performance. Right now, we are testing a prototype of this circuit |
in our lab. And memristors are by no means hard to fabricate. The titanium dioxide structure can be made in any semiconductor fab currently in existence. (In fact, our hybrid circuit was built in an HP fab used for making inkjet cartridges.) The primary limitation to manufacturing hybrid chips with |
memristors is that today only a small number of people on Earth have any idea of how to design circuits containing memristors. I must emphasize here that memristors will never eliminate the need for transistors: passive devices and circuits require active devices like transistors to supply energy. The potential of |
the memristor goes far beyond juicing a few FPGAs. I have referred several times to the similarity of memristor behavior to that of synapses. Right now, Greg is designing new circuits that mimic aspects of the brain. The neurons are implemented with transistors, the axons are the nanowires in the |
crossbar, and the synapses are the memristors at the cross points. A circuit like this could perform real-time data analysis for multiple sensors. Think about it: an intelligent physical infrastructure that could provide structural assessment monitoring for bridges. How much money—and how many lives—could be saved? I’m... |
the memristor will change circuit design in the 21st century as radically as the transistor changed it in the 20th. Don’t forget that the transistor was lounging around as a mainly academic curiosity for a decade until 1956, when a killer app—the hearing aid—brought it into the marketplace. My guess |
is that the real killer app for memristors will be invented by a curious student who is now just deciding what EE courses to take next year. About the Author R. STANLEY WILLIAMS, a senior fellow at Hewlett-Packard Labs, wrote this month’s cover story, ”How We Found the Missing Memristor.” |
Earlier this year, he and his colleagues shook up the electrical engineering community by introducing a fourth fundamental circuit design element. The existence of this element, the memristor, was first predicted in 1971 by IEEE Fellow Leon Chua, of the University of California, Berkeley, but it took Williams 12 years |
Mercury in the Morning The planet Mercury -- the planet closest to the Sun -- is just peeking into view in the east at dawn the next few days. It looks like a fairly bright star. It's so low in |
the sky, though, that you need a clear horizon to spot it, and binoculars wouldn't hurt. Mercury is a bit of a puzzle. It has a big core that's made mainly of iron, so it's quite dense. Because Mercury is |
so small, the core long ago should've cooled enough to form a solid ball. Yet the planet generates a weak magnetic field, hinting that the core is still at least partially molten. The solution to this puzzle may involve an |
iron "snow" deep within the core. The iron in the core is probably mixed with sulfur, which has a lower melting temperature than iron. Recent models suggest that the sulfur may have kept the outer part of the core from |
solidifying -- it's still a hot, thick liquid. As this mixture cools, though, the iron "freezes" before the sulfur does. Small bits of solid iron fall toward the center of the planet. This creates convection currents -- like a pot |
of boiling water. The motion is enough to create a "dynamo" effect. Like a generator, it produces electrical currents, which in turn create a magnetic field around the planet. Observations earlier this year by the Messenger spacecraft seem to support |
that idea. But Messenger will provide much better readings of what's going on inside Mercury when it enters orbit around the planet in 2011. Script by Damond Benningfield, Copyright 2008 For more skywatching tips, astronomy news, and much more, read |
Teacher Tip: instead of addressing the class as... Maps: Behold ORBIS, a Google Maps for the Roman... → Have you ever wondered how much it would cost to travel from |
Londinium to Jerusalem in February during the heyday of the Roman Empire? Thanks to a project helmed by historian Walter Scheidel and developer Elijah Meeks of Stanford University, all of |
your pressing queries about Roman roadways can be answered! This is ORBIS, an online simulation (and thoroughly brainy time sink) that allows you to... "Telling the Time" presentation → Don't |
Requirements for proficiency in Norwegian The Norwegian language is the primary language of instruction at Norwegian institutions of higher education. Some foreign students learn Norwegian before they continue with further studies in Norway. Below is an overview of the language requirements for foreign students applyin... |
general acceptance into an institution, applicants outside of the Nordic countries must meet one of the following requirements: - Successfully passed 'Norwegian as a second language' from upper secondary school. - Sucessfully passed Level 3 in Norwegian at a university. - Successfully passed one-year study in Norwegian... |
Monitor drivers vs. video adapter drivers: How are they different and which do I need? Monitor drivers are specific to the monitor. They are usually text files that tell the operating system what the monitor is and what it is capable of. They are not required for the monitor to |
function. Video adapter drivers Your video adapter lets your computer communicate with a monitor by sending images, text, graphics, and other information. Better video adapters provide higher-quality images on your screen, but the quality of your monitor plays a large role as well. For example, a monochrome monitor can... |
colors no matter how powerful the video adapter is. A video driver is a file that allows your operating system to work with your video adapter. Each video adapter requires a specific video driver. When you update your video adapter, your operating system will provide a list and let you |
pick the appropriate video driver for it. If you do not see the video driver for your adapter in the list, contact the manufacturer of your video adapter to get the necessary video driver. |
In 1962 President John F. Kennedy’s administration narrowly averted possible nuclear war with the USSR, when CIA operatives spotted Soviet surface-to-surface missiles in Cuba, after a six-week gap in intelligence-gathering flights. In their forthcoming book Blind over Cuba: The Photo Gap and the Missile Crisis, co-auth... |
call stemming directly from a decision made in a climate of deep distrust between key administration officials and the intelligence community. Using recently declassified documents, secondary materials, and interviews with several key participants, the authors weave a story of intra-agency conflict, suspicion, and disc... |
Congress and the public in the dark about what really happened. We asked Barrett, a professor of political science at Villanova University, to discuss the actual series of events and what might have happened had the CIA not detected Soviet missiles on Cuba. The Actual Sequence of Events . . . “Some months after the Cub... |
member of the Armed Services Committee of the House of Representatives criticized leaders of the Kennedy administration for having let weeks go by in September and early October 1962, without detecting Soviet construction of missile sites in Cuba. It was an intelligence failure as serious as the U.S. ignorance that pre... |
said. Secretary of Defense Robert McNamara aggressively denied that there had been an American intelligence failure or ineptitude with regard to Cuba in late summer 1962. McNamara and others persuaded most observers the administration’s performance in the lead-up to the Crisis had been almost flawless, but the legislat... |
western Cuba for about a six week period. There were varying reasons for this, but the most important was that the Kennedy administration did not wish to have a U-2 “incident.” Sending that aircraft over Cuba raised the possibility that Soviet surface-to-air missiles might shoot one down. Since it was arguably against ... |
aircrafts over another country, should one be shot down, there would probably be the same sort of uproar as happened in May 1960, when the Soviet Union shot down an American U-2 flying over its territory. Furthermore, most State Department and CIA authorities did not believe that the USSR would put nuclear-armed missil... |
Therefore, the CIA was told, in effect, not even to request permission to send U-2s over western Cuba. This, at a time when there were growing numbers of reports from Cuban exiles and other sources about suspicious Soviet equipment being brought into the country.As we now know, the Soviets WERE constructing missile sit... |
would call “the business end of Cuba,” i.e., the western end, in the summer/autumn of 1962. Fortunately, by mid-October, the CIA’s director, John McCone, succeeded in persuading President John F. Kennedy to authorize one U-2 flight over that part of Cuba and so it was that Agency representatives could authoritatively i... |
CIA had faced White House and State Department resistance for many weeks about this U-2 matter." What Could Have Happened . . . “What if McCone had not succeeded in persuading the President that the U.S. needed to step up aerial surveillance of Cuba in mid-October? What if a few more weeks had passed without that cruci... |
flight and its definitive photography of Soviet missile site construction? Remember to check out Blind over Cuba: The Photo Gap and the Missile Crisis, which is being published this fall!If McCone had been told “no” in the second week of October, perhaps it would have taken more human intelligence, trickling in from Cu... |
would have approved a risky U-2 flight.The problem JFK would have faced then is that there would have been a significant number of operational medium-range missile launch sites. Those nuclear-equipped missiles could have hit the southern part of the U.S. Meanwhile, the Soviets would also have progressed further in cons... |
of the continental United States.If JFK had not learned about Soviet nuclear-armed missiles until, say, November 1st, what would the U.S. have done?There is no definitive answer to that question, but I think it’s fair to say that the President would have been under enormous pressure to authorize—quickly--a huge U.S. ai... |
thing which discovery of the missile sites in mid-October gave JFK was some time to negotiate effectively with the Soviet Union during the “Thirteen Days” of the crisis. I don’t think there would have been such a luxury if numerous operational missiles were discovered a couple weeks later.No wonder President Kennedy fe... |
CIA (with its photo interpreters) and the Air Force (which piloted the key U-2 flight). The intelligence he received on October 16th was invaluable. I think he knew that if that intelligence had not come until some weeks later, there would have been a much greater chance of nuclear war between the U.S. and the Soviet U... |
If you have ever used the Windows Copy (Ctrl+C) to copy objects to the clipboard and then the Windows Paste (Ctrl+V) to copy/paste AutoCAD object(s), then you know that those clipboard object(s) will have the lower left-hand corner of their extents as the base point (not very precise)... and this always reminds me of s... |
(e.g.: Paint or even the wonderful AutoCAD Button Editor!) that have you draw a circle like a rectangle. (annoying to say the least!) With AutoCAD you can use the keyboard shortcut of (Ctrl+Shft+C) to pick a base point for your clipboard object(s). COPYBASE is the actual command, and then you can paste to a precise poi... |
DWG file using the keyboard shortcut of (Ctrl+Shift+V). This is the PASTEBLOCK command or you can also use the PASTEORIG command if the COPYBASEd object(s) go in the same exact spot in the receiving DWG file. Also it is important to note: If you do use the Ctrl+Shift+V PASTEBLOCK method and want to leave it as a block,... |
assign a name for the block, which is something like "A$C11A06AFD" or "A$C1F7A5022" ... Either use the RENAME command, or use EXPLODE or XPLODE, also watch your layers, with regards to the object(s) original layers and where this new "block" is being INSERTed... or where they go if they are EXPLODEd vs. XPLODEd. (I wil... |
On January 16, 1863, Walt Whitman wrote a pained letter to his brother, Thomas Jefferson Whitman, in which he bemoaned the Union’s recent defeat at Fredericksburg as the most “complete |
piece of mismanagement perhaps ever yet known in the earth's wars.” While Whitman today is celebrated as one of America’s greatest poets, works like Leaves of Grass, penned in the |
1850s, were seen as scandalous by an American reading public unready for Whitman’s unconventional lifestyle. An opponent of slavery, Whitman supported the Union with the poem Beat! Beat! Drums and |
volunteered as a nurse in army hospitals. After Lincoln’s assassination in 1865, Whitman penned Oh Captain, My Captain, eulogizing the President for having navigated the ship of state through the |
The Neighbor Squirrel These busy fluffballs have lost their fear of most predators - and they help plant pecan trees. By Sheryl Smith-Rodgers Have you ever watched an eastern fox squirrel (Sciurus niger) bury an acorn or pecan? A nuzzle here, another there, then he hurriedly pushes the leaves and |
grass over the site before scampering up the closest tree. Minutes later, he's back with another nut. Over the course of three months, that industrious squirrel can bury several thousand pecans. Come winter, when food's scarce, he'll find them again with his excellent sense of smell. Some will escape his |
appetite, though, and sprout into saplings, which is how many native nut trees get planted. Eastern fox squirrels - the state's most common and wide-ranging squirrel and a popular game animal, too - occur in forests and riparian habitats. They also easily adapt to cities and neighborhoods, where they've lost |
most of their fear of natural predators. "Playing the call of a red-tailed hawk didn't phase squirrels on campus," reports Bob McCleery, a wildlife lecturer at Texas A&M University, who has studied urban squirrels in College Station. "When we played a coyote call in the Navasota river bottom, a squirrel |
immediately flattened itself in the crotch of a tree for a good five minutes." When agitated, fox squirrels - whose fur closely resembles that of a gray fox - bark and jerk their long, bushy tails, which they use for balance when scampering on utility lines and other high places. |
Ragtime and blues fused ‘All That Jazz’ By Laura Szepesi Published: Sunday, March 17, 2013, 7:09 p.m. Updated: Monday, March 18, 2013 EDITOR'S NOTE: Thursday marks the 85th birthday of well-known Connellsville jazz trombonist Harold Betters. We salute him with this four-part series, starting today with a brief history ... |
the earliest music recordings became available to the public. It grew out of ragtime, which many sources claim is the first true American music. Like jazz, ragtime has Southern roots, but was also flavored by the southern Midwest. It was popular from the late 1800s to around 1920. It developed |
in African American communities, a mix of march music (from composers such as John Philip Sousa), black songs and dances including the cakewalk. Ragtime: Dance on Eventually, ragtime spread across the United States via printed sheet music, but its roots were as live dance music in the red light districts |
of large cities such as St. Louis and New Orleans. Ernest Hogan is considered ragtime's father. He named it ragtime because of the music's lively ragged syncopation. Ragtime faded as jazz's following grew. However, composers enjoyed major success in ragtime's early years. Scott Joplin's 1899 “Maple Leaf Rag” was a |
hit, as was his “The Entertainer,” which was resurrected as a Top 5 hit when it was featured in the 1974 movie “The Sting” starring Robert Redford and Paul Newman. Born of ragtime, jazz was also heavily influenced by the blues. Blues originated in the late 1800s, but in the |
deep South. It is an amalgam of Negro spirituals, work songs, shouts, chants and narrative lyrics. Fused with blues Like jazz, the blues comes in many forms: delta, piedmont, jump and Chicago blues. Its popularity grew after World War II when electric guitars — rather than acoustic guitars — became |
popular. By the early 1970s, blues had formed another hybrid: blues rock. While ragtime is jangly and spirited, the blues takes after its name: blue, or melancholy. Its name is traced to 1912 when Hart Ward copyrighted the first blues song, “Dallas Blues.” Jazz — as a mix of ragtime |
and blues — has fused into many styles since its emergence. In the 1910s, New Orleans jazz was the first to take off. In the 1930s and 1940s, Big Band swing, Kansas City jazz and bebop prevailed. Other forms include cool jazz and jazz rock; today, there's even cyber jazz. |
Jazz: Always changing The late jazz trombone player J.J. Johnson summed jazz up as restless. “It won't stay put ... and never will,” he was quoted as saying, according to various sources. Johnson's sentiment is heartily endorsed by Connellsville jazz trombonist Harold Betters. Betters turns 85 years old this week. |
He will share decades of his memories about music and growing up in Connellsville as his March 21 birthday approaches. Laura Szepesi is a freelance writer. Tuesday: Just how did Harold Betters decide to play the trombone? - Uniontown police investigate shooting injury - Upper Tyrone family helps pet overcome |
paralysis - Several Fayette boroughs have contested races - Recap of the death of Connellsville police officer McCray Robb in 1882 - Connellsville police officer recognized 131 years after death - Fayette County man accused of receiving stolen property, multiple drug offenses - Connellsville set to debut model-railroad... |
2014 - Connellsville airport will remain open - Connellsville mayoral candidate Joshua DeWitt held for trial in chop shop case - South Connellsville man charged in pedestrian accident - Connellsville council to make appointments, reappointments You must be signed in to add comments To comment, click the Sign in or |
Welcome to BSA Troop 51 based out of Waterford, MI. Please take a look around and have a great day. How Scouting Started in the United States One day in 1909 in London, England, an American visitor, William D. Boyce, |
lost his way in a dense fog. He stopped under a street lamp and tried to figure out where he was. A boy approached him and asked if he could be of help. You certainly can, said Boyce. He told |
the boy that he wanted to find a certain business office in the center of the city. I’ll take you there, said the boy. When they got to the destination, Mr. Boyce reached into his pocket for a tip. But |
the boy stopped him. No thank you, sir. I am a Scout. I won’t take anything for helping. A Scout? And what might that be? asked Boyce. The boy told the American about himself and about his brother scouts. Boyce |
became very interested. After finishing his errand, he had the boy take him to the British Scouting office. At the office, Boyce met Lord Robert Baden-Powell, the famous British general who had founded the Scouting movement in Great Britain. Boyce |
was so impressed with what he learned that he decided to bring Scouting home with him. On February 8, 1910, Boyce and a group of outstanding leaders founded the Boy Scouts of America. From that day forth, Scouts have celebrated |
February 8, as the birthday of Scouting in the United States. What happened to the boy who helped Mr. Boyce find his way in the fog? No one knows. He had neither asked for money nor given his name, but |
he will never be forgotten. His good turn helped bring the scouting movement to our country. In the British Scout Training Center at Gilwell Park, England, Scouts from the United States erected a statue of an American Buffalo in honor |
of this unknown scout. One good turn to one man became a good turn to millions of American Boys. Such is the power of a good turn. Hence the Scout Slogan: DO A GOOD TURN DAILY |
The diagnosis of Trichotillomania (TM) is synonymous with the act of recurrently pulling one’s own body hair resulting in noticeable thinning or baldness. (American Psychiatric Association, Diagnostic and statistical manual of mental disorders, 2000, p. 674) Sites of hair pulling can include any area of the body in whi... |
pubis area. (Kraemer, 1999, p. 298) The disorder itself is categorized in the DSM-IV-TR as an “Impulse Control Disorder Not Elsewhere Classified” along with disorders like Pathological Gambling, Pyromania, Kleptomania, and Intermittent Explosive Disorder. Although TM was previously considered to be a rare disorder, mor... |
1999, p. 298) This prevalence rate is significantly higher than the lifetime prevalence rate of .6% that is cited as a potential baseline among college students the DSM-IV-TR. (4th ed., text rev.; DSM-IV-TR; American Psychiatric Association, 2000, p. 676) The condition appears to be more common among women and the peri... |
is customary with most DSM-IV-TR diagnoses, the act of hair pulling cannot be better accounted for by another mental disorder (like delusions, for example) or a general medical condition. Like every disorder in the DSM-IV-TR, the disturbance must cause significant distress or impairment in functioning. (4th ed., text r... |
understood in order to complete the differential diagnosis of TM. Alopecia is a condition of baldness in the most general sense. (Shiel, Jr. & Stoppler, 2008, p. 14) Other medically related causes of alopecia should be considered in the differential diagnosis of TM, especially when working with an individual who deny p... |
Lichen Planopilaris (also known as Acuminatus), Folliculitis Decalvans, Pseudopelade of Brocq, and Alopecia Mucinosa (Follicular Mucinosis). (4th ed., text rev.; DSM-IV-TR; American Psychiatric Association, 2000, p. 676) Comprehensive coverage of these medical conditions is beyond the scope of this article – all of the... |
that bear mentioning. Although the constellation of features covered here is not sufficient to warrant a diagnosis in isolation, they can aid in the differential diagnosis process. Alopecia, regardless of the cause, has been known to lead sufferers to tremendous feats of avoidance so that the hair loss remains undetect... |
loss) might be uncovered is a common occurrence. In cases where individual’s focus of attention is on the head or scalp, it is not uncommon for affected individuals to attempt to hide hair loss by adopting complimentary hair styles or wearing other headwear (e.g., hats, wigs, etc). These avoidance behaviors will be the... |
addition to avoidant behavior and elaborate attempts to “cover it up,” individuals with TM frequently present with clinically significant difficulty in areas such as self-esteem and mood. Comorbidity, or the presence of one or more disorders in the addition to a primary diagnosis, is the rule not the exception in the s... |
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