Abstract-In an optical WDM mesh network, different protection schemes (such as dedicated or shared protection) can be used to improve the service availability against network failures. However, in order to satisfy a connection's service-availability requirement in a cost-effective and resource-efficient manner, we need a systematic mechanism to select a proper protection scheme for each connection request while provisioning the connection. In this paper, we propose to use connection availability as a metric to provide differentiated protection services in a wavelength-convertible WDM mesh network.We develop a mathematical model to analyze the availabilities of connections with different protection modes (i.e., unprotected, dedicated protected, or shared protected). In the shared-protection case, we investigate how a connection's availability is affected by backup resource sharing. The sharing might cause backup resource contention between several connections when multiple simultaneous (or overlapping) failures occur in the network. Using a continuous-time Markov model, we derive the conditional probability for a connection to acquire backup resources in the presence of backup resource contention. Through this model, we show how the availability of a shared-protected connection can be quantitatively computed.Based on the analytical model, we develop provisioning strategies for a given set of connection demands in which an appropriate, possibly different, level of protection is provided to each connection according to its predefined availability requirement, e.g., 0.999, 0.997. We propose integer linear programming (ILP) and heuristic approaches to provision the connections cost effectively while satisfying the connections' availability requirements. The effectiveness of our provisioning approaches is demonstrated through numerical examples. The proposed provisioning strategies inherently facilitate the service differentiation in optical WDM mesh networks.

Organic single‐crystalline semiconductors are highly desired for the fabrication of integrated electronic circuits, yet their uniform growth and efficient patterning is a huge challenge. Here, a general solution procedure named the “soft‐template‐assisted‐assembly method” is developed to prepare centimeter‐scale monolayer molecular crystal (MMC) arrays with precise regulation over their size and location via a capillary‐confinement crystallization process. It is remarkable that the field‐effect mobility of the array is highly uniform, with variation less than 4.4%, which demonstrates the most uniform organic single‐crystal arrays ever reported so far. Simulations based on fluid dynamics are carried out to understand the function mechanism of this method. Thanks to the ultrasmooth crystalline orientation surface of MMCs, high‐quality p–n heterojunction arrays can be prepared by weak epitaxy growth of n‐type material atop the MMC. The p–n heterojunction field‐effect transistors show ambipolar characteristics and the corresponding inverters constructed by these heterojunctions exhibit a competitive gain of 155. This work provides a general strategy to realize the preparation and application of logic complementary circuits based on patterned organic single crystals.

In this study, two processes to fabricate casting mold, conventional sand casting process and additive manufacturing or 3D printing process, are comparatively investigated. The two processes were compared in terms of their weight saving, surface finish, design allowance, and fettling work. The results show that there are significant advantages in using additive manufacturing in the production of mold. The 3D printed molds provide substantial saving of sand used, design allowances and fettling work. The mechanical properties of 3D printed molds are also higher than the conventional ones due to good bonding strength during 3D printing.

This study demonstrates that nanoporous materials possess good adsorption capacities for Rhodamine B in water.