Hydrothermal synthesis of MnO2/CNT nanocomposite with a CNT core/porous MnO2 sheath hierarchy architecture for supercapacitors

MnO2/carbon nanotube [CNT] nanocomposites with a CNT core/porous MnO2 sheath hierarchy architecture are synthesized by a simple hydrothermal treatment. X-ray diffraction and Raman spectroscopy analyses reveal that birnessite-type MnO2 is produced through the hydrothermal synthesis. Morphological characterization reveals that three-dimensional hierarchy architecture is built with a highly porous layer consisting of interconnected MnO2 nanoflakes uniformly coated on the CNT surface. The nanocomposite with a composition of 72 wt.% (K0.2MnO2·0.33 H2O)/28 wt.% CNT has a large specific surface area of 237.8 m2/g. Electrochemical properties of the CNT, the pure MnO2, and the MnO2/CNT nanocomposite electrodes are investigated by cyclic voltammetry and electrochemical impedance spectroscopy measurements. The MnO2/CNT nanocomposite electrode exhibits much larger specific capacitance compared with both the CNT electrode and the pure MnO2 electrode and significantly improves rate capability compared to the pure MnO2 electrode. The superior supercapacitive performance of the MnO2/CNT nancomposite electrode is due to its high specific surface area and unique hierarchy architecture which facilitate fast electron and ion transport

Plasma-Assisted Synthesis of Carbon Nanotubes

The application of plasma-enhanced chemical vapour deposition (PECVD) in the production and modification of carbon nanotubes (CNTs) will be reviewed. The challenges of PECVD methods to grow CNTs include low temperature synthesis, ion bombardment effects and directional growth of CNT within the plasma sheath. New strategies have been developed for low temperature synthesis of single-walled CNTs based the understanding of plasma chemistry and modelling. The modification of CNT surface properties and synthesis of CNT hybrid materials are possible with the utilization of plasma

XMAM:X-raying Models with A Matrix to Reveal Backdoor Attacks for Federated Learning

Federated Learning (FL) has received increasing attention due to its privacy protection capability. However, the base algorithm FedAvg is vulnerable when it suffers from so-called backdoor attacks. Former researchers proposed several robust aggregation methods. Unfortunately, many of these aggregation methods are unable to defend against backdoor attacks. What's more, the attackers recently have proposed some hiding methods that further improve backdoor attacks' stealthiness, making all the existing robust aggregation methods fail. To tackle the threat of backdoor attacks, we propose a new aggregation method, X-raying Models with A Matrix (XMAM), to reveal the malicious local model updates submitted by the backdoor attackers. Since we observe that the output of the Softmax layer exhibits distinguishable patterns between malicious and benign updates, we focus on the Softmax layer's output in which the backdoor attackers are difficult to hide their malicious behavior. Specifically, like X-ray examinations, we investigate the local model updates by using a matrix as an input to get their Softmax layer's outputs. Then, we preclude updates whose outputs are abnormal by clustering. Without any training dataset in the server, the extensive evaluations show that our XMAM can effectively distinguish malicious local model updates from benign ones. For instance, when other methods fail to defend against the backdoor attacks at no more than 20% malicious clients, our method can tolerate 45% malicious clients in the black-box mode and about 30% in Projected Gradient Descent (PGD) mode. Besides, under adaptive attacks, the results demonstrate that XMAM can still complete the global model training task even when there are 40% malicious clients. Finally, we analyze our method's screening complexity, and the results show that XMAM is about 10-10000 times faster than the existing methods.Comment: 23 page

地域経済成長と金融発展 : 中国における地域間収斂と銀行業の費用効率性に関する実証分析

Chapter One Introduction Chapter Two General Situation of Chinese Economy Chapter Three Chinese Regional Unbalanced Economic Development Chapter Four Economic and Financial Determinations of Foreign Capital Distribution in China Chapter Five Transition Character and Cost Efficiency of Chinese Banking Industry Chapter Six ConclusionsSubmitted by アルバイト QIR ([email protected]) on 2013-05-15T02:29:56Z No. of bitstreams: 2 econ176.pdf: 3090375 bytes, checksum: 44771559a1e2fd4d0d14cfdc00ac4f65 (MD5) econ176_abstract.pdf: 248313 bytes, checksum: e315639b4f03abdc51f1ae5546927c83 (MD5)Made available in DSpace on 2013-05-15T02:29:56Z (GMT). No. of bitstreams: 2 econ176.pdf: 3090375 bytes, checksum: 44771559a1e2fd4d0d14cfdc00ac4f65 (MD5) econ176_abstract.pdf: 248313 bytes, checksum: e315639b4f03abdc51f1ae5546927c83 (MD5)経済学府_経済工学専攻At the beginning of Reform and Openness in 1978, a political slogan, ‘let some people and some regions get rich first, others will be brought along, and through this process national common prosperity will be gradually achieved\u27, was proposed by Chinese central government. Worldwide admitted, continuous and spectacular economic growth certainly endorses the accomplishment of this political slogan particularly. There is no doubt that the target of ‘some people and some regions get rich first’ has been achieved after decades of sustainable high-speed economic growth, having participating in WTO in 2001 as well as having ascended to the second largest GDP country in 2011. With the proposal of new political slogan ‘construct a harmonious society’ several years ago, the political goal of ‘achieving common prosperity’ is put forward once more. This dissertation focuses on a particular aspect of China\u27s ‘build in a harmonious society’ issue in its economic boom proceeds, from both the economic side and financial development side. This dissertation empirically investigates how the development of the financial market has an influence upon the regional economic growth in China. Specifically, the author focuses on the impulsive financing force of the external way of foreign investors (foreign capital utilization, foreign shares within the Chinese banking industry) and foreign rivals (foreign banking assets), as well as the domestic way of Chinese financing system self-reform (especially the Chinese banking industry). Firstly, the author quantifies the degree of regional economic convergence (or divergence inversely) in Chapter 3. Distinguishing from former researches, this dissertation is aroused by the inquiry of ‘whether reforms benefit generating a convergent economic growth’. Evidence co-proves that regional economic growth convergence significantly exists in the post-reform period (1978-2008). However, the post-financial-reform period (1978-1994) shows weak δ^2 divergence or weak β convergence. Therefore, the economic reform accelerates convergent speed, whereas the financial reform slows down this outstanding trend. Secondly, the author empirically investigates determinations of external foreign financial utilization in Chinese regions in Chapter 4. Other existing researches have investigated the decisive role of FDI in Chinese economic growth on an aggregate level (namely in all industries). Distinguishing from these previous studies, a special focus is given to a separated foreign capital inwards into regional financial intermediation in this dissertation. However, aggregate foreign capital utilization is also employed as an object of basis. According to the results of our empirical analysis, the economic factors, rather than the financial factors, are confirmed more significantly in aggregate foreign capital attraction. On the other hand, the financial determinants show significantly positive effects to foreign bank asset distribution. In the concrete, a pluralistic, developed financial institution with a large but low-efficiency banking industry attracts foreign rivals in the banking industry. Thirdly, measurements of banking industry cost efficiency and influence factors are the bright spots in Chapter 5. Stochastic Frontier Approach (SFA) was chosen as the method of cost efficiency measurement. The empirical results show that the category of the 1990s newly established policy banks is most cost efficient. According to the empirical results, the participation of foreign minority ownership has a significantly positive impact on the cost efficiency of the banking industry, in spite of a lack of weight strength. And the market-oriented factor (total asset expansion) has a statistically significant impact on the cost efficiency, while the government intervention (credit control) does not. These results verifies the evidence that the market-oriented factor plays a more crucial and substantial role than government intervention in Chinese banking industry reform during the post-WTO period (2002-2009). In Summary, both the internal domestic financial and the external foreign financial approaches impact on Chinese fast economic growth. Introducing competition, especially external foreign force, into banking industry is proved to be an effective approach to cost efficiency improvement. However, foreign capital generally emphasizes profitability. If the government does not work out any measure except for deregulating, foreign capital may invest only to the East region. As a result, the economic disparity between regions must be accelerated. To narrow the enlarged regional gaps, the government should take a feasible and practical measure which induces foreign capital to make inroads into financial market in less developed region. As a first step, tax reduction or subsidies for foreign investors who invest into financial institutions in West and Midland region is worth considering. On long terms, market-oriented competition should be the core reform orientation for the goals of both ‘get rich’ and ‘achieve national common prosperity’

Cost-efficient decarbonization of local energy systems by whole-system based design optimization

On the way toward Net Zero 2050, the UK government set the 2035 target by slashing 78 % emissions compared to the 1990-level. To help understand how an electrified local energy system could contribute to this target and the associated cost, we develop a whole-system based local energy optimization (LEO) model. The model captures a series of state-of-the-art technologies including building fabric retrofit, battery storage, electro-mobility, electro-heating, demand response, distributed renewable, and Peer-to-Peer (P2P) energy trading. And the model enables trade-off assessment between cost and emissions minimization, compares two system operating modes, i.e., cost-oriented and grid-impact-oriented, and evaluates the impacts from weather risks and capital cost assumptions. A case study in Wales reveals (1) capital cost assumptions can lead up to 30.8 % overall cost difference of the local energy system; (2) operating the system in cost-oriented mode can save up to 5 % cost than in the grid-impact-oriented mode; (3) electro-heating by heat pumps has the highest priority among all investigated technologies. Overall, this study demonstrates how to design and operate a cost-efficient and electrified UK local energy system by the whole-system incorporation of near-term technical and business model advances towards a decarbonized future

Planning urban energy systems adapting to extreme weather

In the context of increasing urbanization and climate change globally, urban energy systems (UES) planning needs adequate consideration of climate change, particularly to ensure energy supply during extreme weather events (EWE) such as heatwaves, floods, and typhoons. Here we propose a two-layer modeling framework for UES planning considering the impact of EWE. An application of the framework to a typical coastal city of Xiamen, China reveals that deploying energy storage (i.e., pumped hydro and battery) offers significant flexibility to ensure the critical demand is met during typhoon as a typical EWE and avoids over investment in supply technologies. This requires an extra 2.8% total cost on investment and operation of UES for 20 years. Planning energy systems with proper consideration of EWE can ensure robust urban energy services even with increasing penetration of fluctuating renewables, and we offer a flexible and computationally efficient paradigm for UES planning considering the impact of EWE

STRING v9.1: protein-protein interaction networks, with increased coverage and integration

Complete knowledge of all direct and indirect interactions between proteins in a given cell would represent an important milestone towards a comprehensive description of cellular mechanisms and functions. Although this goal is still elusive, considerable progress has been made—particularly for certain model organisms and functional systems. Currently, protein interactions and associations are annotated at various levels of detail in online resources, ranging from raw data repositories to highly formalized pathway databases. For many applications, a global view of all the available interaction data is desirable, including lower-quality data and/or computational predictions. The STRING database (http://string-db.org/) aims to provide such a global perspective for as many organisms as feasible. Known and predicted associations are scored and integrated, resulting in comprehensive protein networks covering >1100 organisms. Here, we describe the update to version 9.1 of STRING, introducing several improvements: (i) we extend the automated mining of scientific texts for interaction information, to now also include full-text articles; (ii) we entirely re-designed the algorithm for transferring interactions from one model organism to the other; and (iii) we provide users with statistical information on any functional enrichment observed in their network