Assembling 2D-material (2DM) nanosheets into micro- and macro-architectures with augmented functionalities requires effective strategies to overcome nanosheet restacking. Conventional assembly approaches involve external binders and/or functionalization, which inevitably sacrifice 2DM's nanoscale properties. Noble metal ions (NMI) are promising ionic crosslinkers, which can simultaneously assemble 2DM nanosheets and induce synergistic properties. Herein, a collection of NMI–2DM complexes are screened and categorized into two sub-groups. Based on the zeta potentials, two assembly approaches are developed to obtain 1) NMI-crosslinked 2DM hydrogels/aerogels for heterostructured catalysts and 2) NMI–2DM inks for templated synthesis. First, tetraammineplatinum(II) nitrate (TPtN) serves as an efficient ionic crosslinker to agglomerate various 2DM dispersions. By utilizing micro-textured assembly platforms, various TPtN–2DM hydrogels are fabricated in a scalable fashion. Afterward, these hydrogels are lyophilized and thermally reduced to synthesize Pt-decorated 2DM aerogels (Pt@2DM). The Pt@2DM heterostructures demonstrate high, substrate-dependent catalytic activities and promote different reaction pathways in the hydrogenation of 3-nitrostyrene. Second, PtCl4 can be incorporated into 2DM dispersions at high NMI molarities to prepare a series of PtCl4–2DM inks with high colloidal stability. By adopting the PtCl4–graphene oxide ink, various Pt micro-structures with replicated topographies are synthesized with accurate control of grain sizes and porosities. 相似文献
We explore the impact of edge states in three types of transition metal dichalcogenides (TMDs), namely metallic Td-phase WTe2 and semiconducting 2H-phase MoTe2 and MoS2, by patterning thin flakes into ribbons with varying channel widths. No obvious charge depletion at the edges is observed for any of these three materials, in contrast to observations made for graphene nanoribbon devices. The semiconducting ribbons are characterized in a three-terminal field-effect transistor (FET) geometry. In addition, two ribbon array designs have been carefully investigated and found to exhibit current levels higher than those observed for conventional one-channel devices. Our results suggest that device structures incorporating a high number of edges can improve the performance of TMD FETs. This improvement is attributed to a higher local electric field, resulting from the edges, increasing the effective number of charge carriers, and the absence of any detrimental edge-related scattering.
Instructors in higher education are disseminating instructional content via podcasting, as many rally behind the technology’s potential benefits. Others have expressed concern about the risks of deleterious effects that might accompany the adoption of podcasting, such as lower class attendance. Yet, relatively few studies have investigated students’ perceptions of podcasting for educational purposes, especially in relation to different podcasting forms: repetitive and supplemental. The present study explored students’ readiness and attitudes towards these two forms of podcasting to provide fundamental information for future researchers and educators. The results indicated that students may not be as ready or eager to use podcasting for repetitive or supplemental educational purposes as much as we think they are, but they could be persuaded. 相似文献
Social networking is one of the major technological phenomena of the Web 2.0, with hundreds of millions of subscribed users.
Social networks enable a form of self-expression for users and help them to socialize and share content with other users.
In spite of the fact that content sharing represents one of the prominent features of existing Social network sites, they
do not provide any mechanisms for collective management of privacy settings for shared content. In this paper, using game
theory, we model the problem of collective enforcement of privacy policies on shared data. In particular, we propose a solution
that offers automated ways to share images based on an extended notion of content ownership. Building upon the Clarke-Tax
mechanism, we describe a simple mechanism that promotes truthfulness and that rewards users who promote co-ownership. Our
approach enables social network users to compose friendship based policies based on distances from an agreed upon central
user selected using several social networks metrics. We integrate our design with inference techniques that free the users
from the burden of manually selecting privacy preferences for each picture. To the best of our knowledge, this is the first
time such a privacy protection mechanism for social networking has been proposed. We also extend our mechanism so as to support
collective enforcement across multiple social network sites. In the paper, we also show a proof-of-concept application, which
we implemented in the context of Facebook, one of today’s most popular social networks. Through our implementation, we show
the feasibility of such approach and show that it can be implemented with a minimal increase in overhead to end-users. We
complete our analysis by conducting a user study to investigate users’ understanding of co-ownership, usefulness and understanding
of our approach. Users responded favorably to the approach, indicating a general understanding of co-ownership and the auction,
and found the approach to be both useful and fair. 相似文献
LiDAR canopy height models (CHMs) can exhibit unnatural looking holes or pits, i.e., pixels with a much lower digital number than their immediate neighbors. These artifacts may be caused by a combination of factors, from data acquisition to post-processing, that not only result in a noisy appearance to the CHM but may also limit semi-automated tree-crown delineation and lead to errors in biomass estimates. We present a highly effective semi-automated pit filling algorithm that interactively detects data pits based on a simple user-defined threshold, and then fills them with a value derived from their neighborhood. We briefly describe this algorithm and its graphical user interface, and show its result in a LiDAR CHM populated with data pits. This method can be rapidly applied to any CHM with minimal user interaction. Visualization confirms that our method effectively and quickly removes data pits. 相似文献
We present The Chinese Room , a visualization interface that allows users to explore and interact with a multitude of linguistic resources in order to decode and correct poor machine translations. The target users of The Chinese Room are not bilingual and are not familiar with machine translation technologies. We investigate the ability of our system to assist such users in decoding and correcting faulty machine translations. We found that by collaborating with our application, end-users can overcome many difficult translation errors and disambiguate translated passages that were otherwise baffling. We also examine the utility of our system to machine translation researchers. Anecdotal evidence suggests that The Chinese Room can help such researchers develop better machine translation systems. 相似文献
We define a formal model of dynamic programming algorithms which we call Prioritized Branching Programs (pBP). Our model is
a generalization of the BT model of Alekhnovich et al. (IEEE Conference on Computational Complexity, pp. 308–322, 2005), which is in turn a generalization of the priority algorithms model of Borodin, Nielson and Rackoff. One of the distinguishing
features of these models is that they not only capture large classes of algorithms generally considered to be greedy, backtracking
or dynamic programming algorithms, but they also allow characterizations of their limitations. Hence they give meaning to
the statement that a given problem can or cannot be solved by dynamic programming. After defining the model, we prove three
main results: (i) that certain types of natural restrictions of our seemingly more powerful model can be simulated by the
BT model; (ii) that in general our model is stronger than the BT model—a fact which is witnessed by the classical shortest
paths problem; (iii) that our model has very real limitations, namely that bipartite matching cannot be efficiently computed
in it, hence suggesting that there are problems that can be solved efficiently by network flow algorithms and by simple linear
programming that cannot be solved by natural dynamic programming approaches. 相似文献