In 1975 Gordon Moore, cofounder of Intel, made the prediction that the number of transistors on an integrated circuit chip would double ever two for at least the next decade. This is Moore’s law and hopefully it represents how rapidly computer science was progressing at the time, and amazingly, still is progressing. Moore’s law has actually remained true since 1975 and it is used as a target for industry. It’s quite incredible to think that the amount of transistors we can jam onto a circuit now is past ten thousand million (10,000,000,000 – ten billion for those using short scale) and in two years time, we will have managed to get that many on again.
There are many occasions in engineering where it is desired for a material to absorb light. Thermal photovoltaic cells, for instance, want to try to absorb as much energy as they can. Any reflection that occurs off a surface is a loss of energy they could have been using and so represents and inherent limit on the efficiency of these cells. In a way this is also true for devices that produce heat. Any of the produced heat from an electric circuit that can be recaptured and reused will overall drastically increase the efficiency of circuits as thermal loss is the man source of inefficiency.
As circuits become more and more integrated the components of the circuits are going to become more and more exposed to different conditions. Now dielectric breakdown is a well known effect where as you begin upping the charge on a capacitor, eventually dielectric you’re using between will simply not be able to handle the strength of the electric field and it breaks down into becoming a conductor. A spark will then leap between the capacitor plates and that’s the stored charge gone. The main theory behind this is called the percolation theory. According to this theory a dielectric within an electric field develops tiny point defects which can connect to other defects in proximity. As the defect concentration increases with growing electric field sooner or later both sides of the dielectric will be connected by a network of defects, dielectric breakdown will occur, and the dielectric’s electrical properties will be significantly changed to become conducting.
The human eye is quite incredible. When it comes to resolving two images it is practically at the physical limit imposed by diffraction, it can identify over one million separate colour hues which is a whole lot more than anyone could ever need and it has intensity detection of about 5nW so maybe 150 visible photons. It’s these properties we use when we observe images as our eyes are able to detect the gradients of colour and of intensity. If we are dealing with greyscale images, in just black and white, then there is no colour and each pixel responds just to the intensity of light falling upon it. To simplify these are the kind of images that we’re discussing today.
It does not take much imagination to think of the many improvements to technology that nanowires would bring. In the future there is no doubt that nanowires will find use in incredibly precise sensors for both forces and chemicals; renewable energy resources where self assembly will be necessary to produce the various substrate layers; and in wearable technology in order to make it as light and as flexible as possible. Of course in order to be used in these applications we have to be able to make nanowires with specific shapes, out of particular materials and with controllable lengths and sizes. Over the years research has been done which allows us to manipulate these attributes with greater precision. However there is still the problem of crystallinity when it comes to nanowires.
A fine needle aspiration biopsy is a technique used to take a small cell sample from organs. There is a scaled up version called a core needle biopsy which is used if a larger sample is needed. Normally for these procedures local anaesthetic will be applied so the patient doesn’t feel discomfort while whichever needle is being used is inserted through the skin and a sample is taken. In order to actually target these needles at the place where the doctors wish to sample it is common to use MRI scans, tomography or ultrasound to aim the needle tip. However, in the case where we’re looking at a small lesion on an organ, it can certainly be difficult to actually image properly increasing the uncertainty in the biopsy results. For instance the prostate is very hard to image and so often oncologists looking for cancerous cells will actually perform multiple, between six and twelve, biopsies looking for any cancerous cells.
Hydrogels are quite incredible materials with both the literal and figurative flexibility to be used in many medical applications. Drug delivery, the support of scaffolding of soft tissue and wound dressings. Their nontoxic biocompatibility is incredible and more than that, the fact they’re pretty much transparent means there has been suggestions of using them in optical applications. The abilities of hydrogels can be pushed further by combining them with metal nanostructures which has unsurprisingly made researchers quite excited to create new avant garde electrical and optical devices. In 2012 it was shown that a gold nanodot array printed on the surface of a hydrogel had resonated at a wavelength which was a function of the shrinking and swelling of the hydrogel. Now since then, 2D structures have been adhered to hydrogel in many ways to many effects but the production of 3D metallic structures has been considerably more difficult.