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"Locks and keys"
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Nancy Clancy sees the future ; Nancy Clancy : secret of the silver key
Third-grader Nancy tries telling fortunes but learns it is a bit more complicated than she thought, and after learning about time capsules, she and Bree discover an old silver key and investigate its story in the hope of finding treasure.
BOOK
Bar Locks and Early Church Security in the British Isles
This book examines the evidence for the measures taken to make church buildings secure or defensible from their earliest times until the later medieval period. In particular it examines the phenomenon of 'bar locks' which the author identifies in many different contexts throughout England, Wales, Scotland and Ireland.
eBook
Invention and technology. Military and security
\"Describes the evolution of warfare and weapons from pre-Civil War to today's modern techniques on land and sea. Also describes the changes in security devices, such as locks and keys. A timeline traces the history of warfare\"--Provided by publisher.
Book
Lock and key colloids
The key to self-assembly
Many functional materials can be created by directing the assembly of colloidal particles into a predetermined structure. Control over particle assembly usually involves tagging them with molecules such as DNA that can recognize and bind each other. But new work shows that shape complementarity — the construction of colloids using a lock-and-key recognition mechanism — offers a simple and effective alternative control mechanism. The keys are colloidal spheres, and monodisperse colloidal particles with a spherical cavity are the locks. The two will spontaneously and reversibly bind via the depletion interaction if their sizes match. This procedure yields complex colloidal structures held together by flexible bonds, and offers a simple yet general means to program and direct colloidal self-assembly.
Many functional materials can be created by directing the assembly of colloidal particles into a desired structure. Control over particle assembly usually involves the use of molecules such as DNA that can recognize and bind each other. Here, a simple and effective alternative is described. Colloidal spheres serve as keys, and monodisperse colloidal particles with a spherical cavity as locks. These will spontaneously and reversibly bind to each other via the depletion interaction if their sizes match.
New functional materials can in principle be created using colloids that self-assemble into a desired structure by means of a programmable recognition and binding scheme. This idea has been explored by attaching ‘programmed’ DNA strands to nanometre-
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and micrometre-
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sized particles and then using DNA hybridization to direct the placement of the particles in the final assembly. Here we demonstrate an alternative recognition mechanism for directing the assembly of composite structures, based on particles with complementary shapes. Our system, which uses Fischer’s lock-and-key principle
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, employs colloidal spheres as keys and monodisperse colloidal particles with a spherical cavity as locks that bind spontaneously and reversibly via the depletion interaction. The lock-and-key binding is specific because it is controlled by how closely the size of a spherical colloidal key particle matches the radius of the spherical cavity of the lock particle. The strength of the binding can be further tuned by adjusting the solution composition or temperature. The composite assemblies have the unique feature of having flexible bonds, allowing us to produce flexible dimeric, trimeric and tetrameric colloidal molecules as well as more complex colloidal polymers. We expect that this lock-and-key recognition mechanism will find wider use as a means of programming and directing colloidal self-assembly.
Journal Article
The key in the satin pocket
In a vintage clothing shop, Nancy discovers an intriguing clue to a mysterious past.
Book
ZrGeTesub.4 Nanoparticles as a Saturable Absorber for Mode-Locked Operations at 1 and 1.55 µm
In the current paper, the nonlinear absorption characteristics and laser modulation performance of the ternary anisotropic semiconductor material ZrGeTe[sub.4] were successfully explored. The recovery time of the ZrGeTe[sub.4]-PVA thin film was measured to be 5.74 ps by the pump–probe technology. By employing ZrGeTe[sub.4] as a saturable absorber, a passive mode-locked Yb-doped fiber laser was demonstrated for the first time. In the 1 µm mode-locked operation, the central wavelength was 1031.29 nm, the pulse repetition rate was 24.85 MHz, and the pulse width was 786.3 ps. In an Er-doped fiber laser operating at a wavelength of 1561.10 nm, the pulse width was as short as 1.26 ps with a repetition rate of 4.38 MHz. The results show that ZrGeTe[sub.4] has excellent broadband nonlinear optical characteristics.
Journal Article
Torsional Vibration Analysis Using Rotational Laser Vibrometers
Torsional vibration is a critical phenomenon in rotor dynamics. It consists of an oscillating movement of the shaft and causes failures in multiple oscillating fields of application. This type of vibration is more difficult to measure than lateral vibration. Torsional vibrometers are generally invasive and require a complicated setup, as well as being inconvenient for field measurements. One of the most reliable, non-invasive, and transportable measuring techniques involves the laser torsional vibrometer. For this research, two laser heads with different measurement capabilities were utilized. An experimental test rig was used to perform a relative calibration of the two laser vibrometers. The frequency of the acting force and the rotation speed of the shaft vary in the same range, which is commonly found in rotating machines. Finally, experimental measurements of torsional vibrations using laser vibrometers were compared with numerical results from a 1D finite element model of the same test rig. The main outcome of this paper is the definition of a reliable measuring procedure to exploit two laser vibrometers for detecting torsional mode-shapes and natural frequencies on real machines. The relative calibration of two different measuring heads is described in detail, and the procedure was fundamental to properly correlate measuring signals in two machine sections. A good correspondence between the numerical and experimental results was found.
Journal Article
The wizard's war
This time Cleo, Evan, and Ms. Crowley (who, it turns out, is the missing Ms. Hilliard's sister) find themselves in a confusing fantasy book, caught up in a war with wizards, elves, trolls, and the mighty Golden Dragon-- and while they manage to find their missing librarian, their quest does not end there.
Book
Initial construct stability of long cephalomedullary nails with superior locking for a complex trochanteric fracture model AO31A2.2– a biomechanical study
Background
Complex fractures of the trochanteric region, as well as fractures located in the directly subtrochanteric region, are controversially discussed around the world regarding the nail type to be used. A long nail is recommended by manufacturers but requires longer surgical and fluoroscopy times. A possible solution could be a nail with an appropriate length which can be locked in a minimally invasive manner by the main aiming device. We aimed to determine if such a nail model (DCN SL nail, SWEMAC, Linköping, Sweden) offers similar structural stability on biomechanical testing on artificial bone as a standard long nail when used to treat complex trochanteric fractures and compared it to long nails usually used in this setting.
Methods
An osteoporotic bone model was chosen. The Swemac Hansson DCN Nail System was used as osteosynthesis material. Two types of nails were chosen: a superior lock nail which can be implanted with a singular targeting device, and a long nail with distal locking using free-hand technique. AO31A2.2 fractures were simulated in a standardised manner. Axial height of the construct, varus collapse, and rotational deformity directly after nail insertion were simulated. A Universal Testing Machine was used. Measurements were made with a stereo-optic tracking system.
Findings
There was a detectable difference in the axial fracture movement resulting in narrowing of the fracture gap. There was no difference in varus collapse or rotational deformity between the nail variants
Conclusion
We conclude that there are small differences which are clinically insignificant and that a superior locking nail can safely be used to manage complex trochanteric fractures.
Journal Article