3D Micromolding of Arrayed Waveguide Gratings on Upconversion Luminescent Layers for Flexible Transparent Displays without Mirrors,Electrodes, and Electric Circuits

A new technique for the fabrication of arrayed waveguide gratings on upconversion luminescent layers for flexible transparent displays is reported. Ho³⁺‐ and Yb³⁺‐codoped NaYF₄ nanoparticles are synthesized by hydrothermal techniques. Transparent films consisting of two transparent polymers on the NaYF₄ nanoparticle films exhibit mechanical flexibility and high transparence in visible region. Patterned NaYF₄ nanoparticle films are fabricated by calcination‐free micromolding in capillaries. Arrayed waveguide gratings consisting of the two transparent polymers are formed on the patterned NaYF₄ nanoparticle films by micromolding in capillaries. Green and red luminescence is observed from the upconversion luminescent layers of the NaYF₄ nanoparticle films in the arrayed waveguide gratings under excitation at 980 nm laser light. Arrayed waveguide gratings on the upconversion luminescent layers are fabricated with Er³⁺‐doped NaYF₄ nanoparticles which can convert two photons at 850 and 1500 nm into single photon at 550 nm. These results demonstrate that flexible transparent displays can be fabricated by constructing arrayed waveguide gratings on upconversion luminescent layers, which can operate in nonprojection mode without mirrors, transparent electrodes, and electric circuits.     

A fast algorithm for translating combinator expressions with BC-chains

A fast algorithm is presented for translating lambda expressions to combinator trees with BC-chains. The time complexity of this algorithm is O (n log n) in the worst case, where n is the length of an input expression. Furthermore it requires only O (n log n) working space. This result achieves a substantial improvement to the previously known algorithm having the quadratic complexity. The basic idea of the algorithm may be applied to practical processing systems, whether they use BC-chains or not.     

Linearity and bisimulation

Exploiting linear type structure, we introduce a new theory of weak bisimilarity for the π-calculus in which we abstract away not only τ-actions but also non-τ actions which do not affect well-typed observers. This gives a congruence far larger than the standard bisimilarity while retaining semantic soundness. The framework is smoothly extendible to other settings involving nondeterminism and state. As an application we develop a behavioural theory of secrecy in the π-calculus which ensures secure information flow for a strictly greater set of processes than the type-based approach, while still offering compositional verification techniques.     

EFFECTIVENESS OF INFORMATION ENTROPY FOR EVALUATION OF GRINDING EFFICIENCY

From the viewpoint of information theory, the necessity that the under size material distribution follows the exponential law is discussed and the effect of differences in the initial particle-size of the material on the energy necessary to grind is examined

It is confirmed that the concept of information entropy is useful not only to discuss the grinding efficiency by experiments but also to make clear that the energy necessary to grind is smaller as the initial particle-size of the material becomes larger. This method becomes even more useful if the amount of surface area increased is considered as well.     

On the expected behaviors of the Dijkstra's shortest path algorithm for complete graphs

Shortest path, shortest spanning tree, complete graph, number of comparisons, expected complexity     

A new ship's auto pilot design through a stochastic model

A new type of ship's autopilot system is designed by a statistical approach. A ship's motion at sea is described by a multi-variable autoregressive model using minimum AIC (Akaike's Information Criterion) procedure. Through the fitted model, the ship's behavior is analyzed and an optimal control law for a ship under a newly introduced criterion function is derived. The feasibility of our control system is checked by both digital and hybrid simulations. The results of the simulation show that with our controller the yaw motion is depressed through smoother and less rudder motion than that of the conventional autopilot systems and the ill effect of rolling is avoided. It is expected that the controller has another merit: it is quite robust for possible changes of external environments. Finally, a successful result of an actual sea test is briefly discussed. Thus, the possibility of realizing an entirely new autopilot system by a stochastic model is demonstrated.     

Temperature acceleration of CMOS IC operating life

We carried out the high temperature operating life test (HTOT) of CMOS ICs which include n-channel ROMs which were contaminated deliberately by leaving naked for a long time in the room ambient before moulding and got the bimodal failure distributions consisting of m = 0.3–0.5 and m = 2.6–3.3 parts in the Weibull chart.At the same time, the activation energy of 1.14 eV was obtained for m = 2.6–3.3 parts. In order to make clear the failure mechanism of the latter part, we made the test devices for detecting channel leakage current (abbrev. TEG) and checked the shift of leakage current and life acceleration due to temperature in HTOT. Then we found that leakage currents of TEGs have an incubation time, their activation energy was nearly equal to that of the CMOS ICs above and m = 2.6–3.3 for CMOS ICs were reasonably explained due to the gradient α of the logarithm of the median leakage current to that of time.Also we got a 40 times longer life for the same CMOS ICs coated with Si₃N₄ film instead of SiO₂. And finally, from these data, we could verify the cause of failure in CMOS ICs.