Search

Efficient, environment-friendly, and energy-saving low-temperature denitration (DeNOx) catalysts, applicable in practical flue gas, have a widespread market for use in small-scale boilers. A novel Ce-based low-temperature honeycomb catalyst was tested in a pilot-scale plant for DeNOx of flue gas from a coal-fired power plant. The pilot test results demonstrated the honeycomb catalyst's ability to endure a high content of water vapor (H2O, 8–10 vol%) and low content of sulfur dioxide (SO2, ≤35 mg m−3) in flue gas at temperatures as low as 100 °C, with >55% DeNOx efficiency over 3400 h and the catalyst showed no deactivation. Physicochemical properties of the catalyst were investigated by various characterization methods, such as Brunauer–Emmett–Teller analysis, X-ray diffraction analysis, inductively coupled plasma, temperature-programmed desorption of NH3, thermogravimetry, and Fourier-transform infrared spectroscopy. The results showed the effectiveness of the selective catalytic reduction unit in preventing the deposition of particulate matter in the flue gas, after being placed in the desulfurization and dust removal unit. However, a small amount of alkali metal and sulfate deposition were detected on the surface and micropores of the catalyst but did not significantly impact the catalyst performance. This catalyst thus has broad potential applicability in actual flue gas.

The development of low-temperature aluminum electrolysis makes it possible to reduce energy consumption and greenhouse gas emissions. The KF-NaF-AlF3-based electrolyte is a promising low-temperature electrolyte for aluminum reduction. The liquidus temperatures of KF-NaF-AlF3 electrolytes with a total cryolite ratio (CRt) fixed at 1.3–2.0, and with different concentrations of NaF (with a step change of 5 mol.%), were investigated by the cooling curve method. The results showed that the liquidus temperature of KF-NaF-AlF3 mixtures increases with the increase of the CRt, which has a bigger influence on the liquidus temperature than the traditional NaF-AlF3 electrolyte currently used in aluminum smelters. When the content of NaF is 10–20 mol.%, the curves of the liquidus temperature vs. NaF content reach a peak. When the NaF content ranges from 30 to 40 mol.%, the liquidus temperature is relatively low (695–900°C). The precipitated order of the compounds in molten KF-NaF-AlF3 electrolytes with a CRt of 1.3 is as follows: K2NaAlF6 (or K3AlF6) → Na3Al5F14 → K2NaAl3F12 → KAlF4.

Two styryl pyrimidine derivatives substituted by p-tosyloxymethyl, Boc-SPm2-OTs and Boc-SPm5-OTs, were designed and successful synthesized, which were labeled by 18F to prepared 18F-SPm2 and 18F-SPm5 by nucleophilic substitution. The radiochemical purities of both 18F-SPm2 and 18F-SPm5 were more than 99%. Both 18F-SPm2 and 18F-SPm5 had ideal lipophilicity (LogP=1-2.5) and can maintaining stability in normal saline for over 3 h and can bind to Aβ selectively, but both 18F-SPm2 and 18F-SPm5 displayed less binding affinity (the Ki values were 246.6 nmol/L and 318.2 nmol/L, respectively). The results of biodistribution in mice demonstrated that both 18F-SPm2 and 18F-SPm5 showed relatively high initial brain uptake, with slow washout from normal brain and obvious defluorination in vivo. In conclusion, both 18F-SPm2 and 18F-SPm5 might not be ideal Aβ imaging agents, and further modifications were needed to improve the disadvantages.

In this paper, the problem of the rapid rise of cathode voltage drop (CVD) in an aluminum smelter enterprise is analyzed and addressed. Among the factors that lead to the increase of the CVD caused by the long-term unstable power supply load, the reduction of the conductive area of the cathode due to the increase of sludge, crusts, and the growth of side ledge was the main reason, and the sodium penetration and expansion were also inevitable. The CVD could be significantly reduced by adjusting the parameters reasonably and clearing the sludge and crusts on the cathode’s surface of the cells manually, but it was not easy to recover to the initial value. To keep the CVD stable over the long term, it was key to stabilize the controlling parameters, and ensure that the cathode surface temperature was slightly higher than the temperature of the liquid bath.

Intelligent recognition of switch state based on computer vision is one of the important research contents of power intelligence. For solving the problem of low recognition rate under poor imaging environment, this paper presents an improved VGG19 network. There are 3 improved aspects: 1) in the first convolutional layer, the convolution features are extracted from the RGB image and the LBP image of the switch, and then the two convolution features are averaged as the output result of the first convolution layer, in order to enhance the adaptability of features to illumination changes and the ability to extract detailed features; 2) in the subsequent 15 convolution layers, the convolution feature output of each layer is averaged with the original input, and then convolved again, so as to extract detail features by secondary convolution; 3) we selects CReLU instead of ReLU as activation function for reducing the redundancy of the convolution kernel. Experiments show that the new method can greatly improve the performance of switch state recognition.

The cryolite ratio (CR) is an important parameter for the electrolyte in aluminum reduction cells. The measurement method for the CR of the KF-NaF-AlF3 system acid (CR

Honeycomb cordierite-based Mn–Ce/Al2O3 (Mn–Ce/Al2O3–C) and Fe–Mn–Ce/Al2O3 (Fe–Mn–Ce/Al2O3–C) catalysts were prepared by an impregnation method and investigated in low-temperature selective catalytic reduction (SCR) of NO with NH3 at 100 °C. The Fe–Mn–Ce/Al2O3–C catalyst exhibited not only higher catalytic activity, but also much better SO2 and H2O resistance in the presence of 30 ppm SO2 and/or 5 vol% H2O than Mn–Ce/Al2O3–C. After doping Fe, the NO conversion of Mn–Ce/Al2O3–C catalyst displayed an increasing trend from 79 to 84% in the absence of SO2 and H2O at 100 °C under a gas hour space velocity of 1667 h−1. The results of characterization indicated that addition of Fe was advantageous to increase BET surface area, pore volume and inhibit loss of surface Mn and Ce species. Additionally, it was helpful for generating higher concentration of Mn4+, more chemisorbed oxygen and more uniform dispersion of amorphous Mn and Ce in the surface of catalyst, which were beneficial to interact with reactants. Furthermore, in contrast to Mn–Ce/Al2O3–C, the SCR activity of Fe–Mn–Ce/Al2O3–C catalyst in the presence of H2O, SO2 and H2O and SO2 were 79, 75 and 64%, with the increase of 14, 18 and 19%, respectively. It is indicated that the addition of Fe could inhibit sulfate formation and thus enhance SO2 resistance. XPS results reveal that the doping of Fe into the ceria lattice led to some Ce4+ transferred into Ce3+ in order to maintain the electrical neutrality, thereby facilitating the reduction of Ce4+ → Ce3+ and the formation of oxygen vacancies. NH3 temperature-programmed desorption (TPD) results imply that the doping of Fe onto Mn–Ce/Al2O3–C can remarkably improve the distribution and concentration of acid sites. All the above factors contributed to the improvement of overall NH3 SCR performance of the Fe–Mn–Ce/Al2O3–C catalyst compared with that of the Mn–Ce/Al2O3–C catalyst.

Power outage accidents will cause huge economic loss to the social economy. Therefore, it is very important to evaluate the economic loss of power outages. By summarizing the existing literature, this paper summarizes the economic impact caused by blackouts, and then it introduces the influence factors that cause the outage loss. Finally, the assessment methods to evaluate direct and indirect economic loss are summarized. Through the summary, it is found that there are many researches on direct economic loss of power outages, but there are few studies on the indirect economic loss of power outages. Finally, the application prospect of the power loss assessment methods is prospected.

With electric power system becoming more and more complex and intelligent these days, its uncertainty also increases. This paper classifies the references of the risk assessment on power system from the aspects of evaluation hierarchy, evaluation category, evaluation model, power system status, time and simulation algorithm. The purpose of this paper is to reveal the research status and compared the advantages and disadvantages of the methods used. And the future development of risk assessment on power system is also prospected.

This paper uses the relevant knowledge of complex network theory to analyze the static characteristic parameters such as node degree, node degree distribution, network average length and node tightness of W city rail transit network, electric power distribution network and load network. The importance index of the nodes is analyzed, by taking W city rail transit network and electric power distribution network as the research object of the composite network. At the same time, this paper points out the important nodes in the rail transit network of W city. The energy efficiency coefficient changes of W city rail transit network and rail transit composite network under random attack and deliberate attack mode is simulated, which provides reference for the subsequent protection and planning of relevant departments.

Detecting workers and equipment through images/videos can assist in safety monitoring, quality control, and productivity management at construction sites. Currently, the dominant method for detecting is Deep Neural Networks (DNNs). To apply this method, the DNNs always need to be trained on image datasets that contain objects at the construction site. However, a large-scale and publicly available image dataset for detecting objects at construction sites is still absent, and this hinders research in this field. In this study, the Moving Objects in Construction Sites (MOCS) image dataset is presented. The dataset contains 41,668 images collected from 174 different construction sites. Thirteen categories of moving objects found in construction sites were annotated. Furthermore, the objects were precisely annotated using per-pixel segmentations to assist in precise object localization. A detailed statistical analysis was performed in this study. Finally, a benchmark containing 15 different DNN-based detectors was made using the MOCS dataset. The results show that all detectors trained on the dataset could detect objects at construction sites precisely and robustly.

Electric vehicle, as a kind of moving load, its behavior of charging and discharging will have a huge impact on the power grid. This article does some researches on coordination charging and discharging strategy of electric vehicles between different regions. Considering the load characteristics of the area and parking rules of electric vehicles, the paper proposes an optimal control strategy from different perspectives of the power grid side, intermediary side and user side. The power grid side considers load fluctuations; the intermediary side considers the benefits of charging and discharging, the user side considers charge-discharge cycles and user convenience. Together it establishes the corresponding multi-objective function and uses multi-objective genetic algorithm to calculate the result. Finally a demonstration is given to prove the validity of this method. Simulation result shows that the multi-objective optimization method can achieve the overall demand of the power grid side, intermediary side and user side.

Article in Chinese. [Purpose/significance] This paper discusses standards development for library demand driven acquisitions and introduces the Demand Driven Acquisition of Monographs (NISO DDA), a recommended practice published by the National Information Standards Organization (NISO) in United States.Libraries in China may draw on U.S. experience during their own DDA application and standards development.[Method/process] Through a literature review, this paper discusses the NISO DDA development background, process, key aspects, impact, and the challenges.[Result/conclusion]NISO DDA laid the foundation for the standardization and sustainable development of DDA. It provides guidelines for the standardized adoption and promotion of DDA on the basis of win-win cooperation by various stakeholders such as libraries, publishers, vendors, and aggregators. It has a positive impact on protecting the interests of all stakeholders in the book supply chain. The sustainable development of DDA continues to face challenges; various stakeholders are still actively exploring the ways in which DDA can be further developed.

Honeycomb cordierite-based Mn–Ce/Al2O3 catalysts were prepared by the impregnation method and used for low-temperature selective catalytic reduction (SCR) of NOx with NH3, with and without SO2 and/or H2O in a homemade fixed-bed tubular reactor. The catalyst reached nearly 80% NOx conversion at 100 °C in the absence of SO2. However, SO2 reduces the catalytic activity (80% to 72%) of the honeycomb cordierite-based Mn–Ce/Al2O3 catalysts under identical conditions. This finding demonstrated that the catalyst exhibited high activity at low temperature and excellent SO2 resistance in the presence of 50 ppm SO2. The fresh and sulfated honeycomb cordierite-based Mn–Ce/Al2O3 catalysts were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), N2 adsorption–desorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetry and differential thermal analysis (TG-DTA), and Fourier transform infrared (FT-IR) spectroscopy. Characterization results indicated that the deactivation by SO2 was primarily the result of the deposition of ammonium hydrogen sulfate and sulfated CeO2 on the catalyst surface during the SCR process. The formed sulfates depressed the catalytic activity via the blocking of pores and the occupation of active sites. Additionally, the competitive adsorption between SO2 and NH3 always decreased the catalytic activity.

For the construction of new generation of smart substation, and provide technical support for the core equipment's quality control, operational maintenance and test, technical standards for the integrated disconnecting circuit breaker are established. The standard system includes a community standard and five enterprise standards. The whole process standardization of the item, method, criterion and implementation of integrated disconnecting circuit breaker is realized, providing a standard basis for its handover debugging, operation, test, evaluation and maintenance. The standard system ensures a stable application of the integrated disconnecting circuit breaker.

Reusing reclaimed water is considered an effective way to abate water shortages in mega cities and protect the ecological status of rivers and lakes. Controlling of riverbed infiltration is an important way to protect the water environment, as it ensures the recycle of groundwater and maintained the groundwater quality in the recharge zone. The composite of attapulgite clay (AC) and modified-AC (MAC), named three-dimensional network adsorbent, was selected as the infiltration reduction materials, and the ability of controlling infiltration and purification were tested. Results showed that the permeability coefficient reached 10−6 cm/s when AC and MAC were mixed at a ratio of 95:5 and 97:3, respectively. And when the layer thickness was 2–10 cm, the infiltration reduction capacity improved with the increased layer thickness and MAC content. The result of fine particles was greater than coarse particles. As the larger average pore diameter of coarse particles, the cumulative infiltration quantity and permeability coefficient of the AC and MAC coarse particles were lower, in the range of 10.98–11.16 %. The adsorption of ammonium nitrogen (NH4 +) was linear while phosphate (PO4-P) adsorption was nonlinear. Reusing reclaimed water could significantly inhibit the adsorption of NH4 + and PO4-P by AC and MAC.

The past three decades have witnessed great changes and developments in the publishing industry in China. One important change is that more and more new local gazetteers (or local histories) and yearbooks are compiled and published in book format. Local gazetteers and yearbooks are also increasingly available in electronic format through commercial databases or as is less known, in public domain. The purpose of this article is to address the following questions: What are new local gazetteers and yearbooks? Why so many titles are published now? Are there any free online full texts available? What are the free online full texts? In addition, I will briefly examine the institutionalization of compiling and publishing local gazetteers and yearbooks in China. Furthermore, I present the result of a survey on freely available online full texts of such materials that I conducted from 2007 through 2008. Given that commercial full-text databases of local gazetteers are unaffordable for most libraries in North America, it is hoped that students, researchers and librarians of Chinese studies shall find the free online full-text materials useful.

This study examines Western-language, particularly English-language, monographs on East Asian studies published in the United States, Canada, England, Australia, and other countries from 2000 through 2005. The study provides a landscape view of the scope and trends of publications for both scholars and librarians in East Asian studies. The data for this study were collected from the YBP’s GOBI (Global Online Bibliographic Information) database, covering publications profiled by YBP from January 1, 2000, through December 31, 2005. The results of data analysis shed light on scholarly currents and publishing trends in East Asian studies over that six-year period.

The rich Chinese oral history collections at Columbia University mainly consist of the Chinese Oral History Project collection, the China Missionaries Project collection, the Academia Sinica Institute of Modern History Oral History collection, and the Zhang Xueliang (Chang Hsuehliang, or Peter H. L. Chang) Oral History collection. This article intends to provide essential information on what is available, how to navigate through the multitudes of the collections, and how to communicate requests for access to Columbia libraries. It offers as an updated, comprehensive, consistent overview of Chinese oral history collections at Columbia for better access by users and librarians alike, particularly for Chinese-language users in Taiwan and China.

Source materials keep their scholarly value unabated with the passage of time. This is true of the Chinese Oral History collections at Columbia. Most of the collections were created, acquired in association with the Chinese Oral History Project undertaken about three decades ago, but they are still frequently inquired about and consulted by students and scholars researching modern China. All the original Chinese oral history collections are kept at the Rare Book and Manuscript Library (RBML) at Columbia. Some difficulties in accessing the collections from afar and at Columbia have been reported by new users. Among other problems, new users assume that records for these Chinese-language oral histories have been completely entered into CLIO (Columbia Libraries Information Online), Columbia’s online catalog, and converted to LC pinyin system, and so are searchable in CLIO, but in fact this is not true. Many authors and titles of the oral histories, if known, are not directly searchable. Some general titles of oral history projects are searchable, and the search results offer substantial useful information in great detail. Yet, few users would search CLIO using the correct general titles, and some specific personal papers and archives cannot be located this way. Moreover, it seems the Journal of East Asian Libraries and other library professional periodicals have not carried any articles focusing on this important oral history collection. The Chinese Oral History project at Columbia officially started in 1958 and ended in 1980. Prof. C. Martin Wilbur, the project co-director, prepared an updated, but unfinished inventory for RBML in 1984. A number of other Chinese-related oral history projects of significant importance were conducted at or collected by Columbia. The available guides, printed in 1972, 1979, and 1984, were collected by some institutions, but they have been found not to be perfect in meeting the research needs of the new generation of users who are used to renewed, updated search tools. The general guide at RBML, which has been very useful, seems to be the aggregate of documents such as guides, inventories, and relevant journal articles from various sources at different time. Many of the documents in the guide are informal documents, with undated handwritten notes and corrections. It is necessary to offer an updated, comprehensive, consistent overview of Chinese oral history collections at Columbia for better access by users and librarians alike. Chinese oral history collections at Columbia mainly consist of the Chinese Oral History Project collection, the China Missionaries Project collection, the Academica Sinica Institute of Modern History oral history collection, and the Zhang Xueliang oral history collection. It is impossible for me to cover all the collections in detail in this article. This article intends to provide essential information on what is available, how to navigate through the multitudes of the collections, and how to communicate requests for access to RBML staff. In particular, it includes the lists of person names in LC pinyin, Chinese and original Romanization, and record titles of the transcribed memoirs, personal papers, and archives that users and librarians may find immediately useful.

The conventional criteria of website evaluation are widely applied in evaluating online information, which is an important component of information literacy instruction in academic institutions. However, mainly from the users' angle and inherently bibliographic, these criteria tend to be general in nature and fail to differentiate the qualities of websites at similar quality levels. Thus, evaluation criteria from webometric perspectives that utilize measurable data and tangible information are needed for more informed assessment. The purpose of this article is to introduce and apply essential webometric criteria to supplement the conventional criteria to improve information literacy instruction. The article first synthesizes the widely used conventional criteria into Six C's for the sake of simplicity and applicability. Then, important webometric criteria of popularity, profundity, luminosity, and error-checking are introduced. Next, the webometric data collected from leading demography research institutions' websites in the U. S. are analyzed. The article concludes that while conventional criteria continue to be convenient and useful, particularly for novel web users, a basic set of webometric criteria can serve as a supplementary tool to provide additional insights into evaluating online resources.

China's recent basic education reform followed and, in a certain way, imitated its economic reform. The economic reform merged the experimental dual (planned and market) price systems into a free market economy and yielded phenomenal success. Basic education reform, however, has not succeeded in transforming the introductory dual-track (key school and regular school) systems into a universal one. This article briefly examines the general process and outcomes of basic education reform. It discusses the following questions: Is basic education reform also a story of success? What significant lessons can the Chinese reform experience offer to other comparable developing countries?

With an introduction to the overall underdevelopment of higher education in China compared with the American counterpart, this article briefly examines the main trends of over two decades of development of the governance and financing systems of China's higher education sector. This article analyzes the resource allocation from governments and revenue generation in institutions under the reform policies of administrative decentralization and financing diversification. The new "Great Leap Forward" in higher education in 1999 and beyond, i.e., the radical and, to a certain extent, desperate mass higher education policy and practice of expanding enrollments in order to spur domestic consumption, is critically analyzed. By examining the ongoing institutional merging and "co-building" and the most recent enrollment expansion, the writer points out the economic significance for higher education of overcoming diseconomies of scale and inefficiencies. However, the long-range outcomes of the seemingly exciting investment in and consumption of mass higher education are difficult to predict.

I investigate the creation, development, contributions and limits of Project Hope, a huge government-endorsed education project seeking non-governmental contributions to overcome educational inadequacy in poverty-stricken rural communities in transitional China. By reexamining the composition of sponsored students, the locations of Hope Primary Schools and non-educational orientations for building and expanding schools, I argue that Project Hope and its Hope School system have not contributed to educational access, equality, equity, efficiency and quality as it should have. Poverty-reduction-oriented curriculum requirements in Hope Primary Schools are theoretically misleading and realistically problematic.