检索结果-南通市图书馆

The Risk Transfer of Non-tradable Risks under Model Uncertainty

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2012年第8期28卷 1597-1614页

作者： yu lian FAN Department of Mathematics North China University of Technology

In the context of model uncertainty, we study the optimal design and the pricing of financial instruments aiming to hedge some of non-tradable risks. For the existence of model uncertainty, the preference can be represented by the robust expected utility （also called maxmin expected utility） which can be put in the framework of sublinear expectation. The problem of maximizing the issuer＇s robust expected utility under the constraint imposed by the buyer can be transformed to the problem of minimizing the issuer＇s convex measure under the corresponding constraint. And here the convex measure measures not only the risks but also the model uncertainties.

关键词： Model uncertainty sublinear expectation indifference pricing risk measure

State synchronization in process-oriented chaincode

在线全文

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2019年第6期13卷 1166-1181页

作者： lian yu Wei-Tek TSAI School of Software&Microelectronics Peking UniversityBeijing 102600China State Key Laboratory of Software Development Environment School of Computer Science&EngineeringBeihang UniversityBeijing 100191China Comp. Info.and Dec.Systems EngineeringArizona State UniversityTempeAZ 85287USA

Business processes often involve operational processes,contracts,and *** modeling of such processes must address regulation monitoring and enforcement and maintain a reliable history of data for *** study proposes modeling business processes as chaincode(CC)on permissioned blockchains(BCs).The challenges encountered by the proposed approach are state synchronizations among distributed nodes(called authnodes)and realtime *** study separates CC executions from the state management of multiple BCs and demonstrates the validity of the proposed approach with a payment authorization system at a Chinese bank.

关键词： blockchains state synchronization chaincode permissioned blockchains concurrent block building

Source-less density measurement using an adaptive neutron-induced gamma correction method

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2023年第8期34卷 115-130页

作者： Qiong Zhang Yi Ge yu-lian Li University of Electronic Science and Technology of China Chengdu 610000China

The use of radioactive isotopes,such as Cs-137,to measure formation density is a common practice;however,it poses high risks such as environmental contamination from lost *** address these challenges,the use of pulsed neutron sources for density measurements,also known as“source-less density”,has emerged as a promising *** collecting gamma counts at different time gates according to the duty cycle of the pulsed sequence,the inelastic gamma component can be isolated to obtain more accurate density ***,the collection of gamma rays during the neutron burst-on period often contains a proportion of capture gamma rays,which can reduce the accuracy of density *** proportion can vary depending on the formation environment and neutron duty *** address these challenges,an adaptive capture gamma correction method was developed for density *** method distinguishes between“burst-on”and“burst-off”periods based on the gamma time spectra,and derives the capture ratio in the burst-on period by iteratively fitting the capture gamma time spectra,resulting in a more accurate net inelastic *** method identifies the end of the pulse by automatically calculating the differential,and fits the capture gamma time spectra using Gaussian process regression,which considers the differences in formation attenuation caused by different *** method was verified through simulations with errors of below 0.025 g/cm3,demonstrating its adaptability and feasibility for use in formation density ***,the proposed method has the potential to minimize the risks associated with radioactive isotopes and improve the accuracy of density measurements in various duty cycles and formation environments.

关键词： Neutron-induced gamma Adaptive correction Source-less density

Different provenance of separate loess sites in Yangtze River Basin and its paleoenvironmental implications

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2019年第7期16卷 1616-1628页

作者： ZHANG Zhi JIA yu-lian School of Geography and Environment Key Laboratory of Poyang Lake Wetland and Watershed ResearchMinistiy of EducationJiangxi Normal UniversityNanchang 330022China College of Chemisty and Chemical Engineering Jiangxi Normal UniversityNanchang 330022China

The dust deposits in the Yangtze River Basin(YRB)have been widely distributed along the Yangtze River *** studies mainly concentrated in its provenance of each loess site,however,the differences in provenance of loess among different sites in this area have rarely been ***,the geochemical characteristics of thelian sand hills and the loess in this area published by previous studies,we suggest that the exposed river valley floodplain caused by weak summer monsoon provided abundant materials to form local dust cells controlled by strong winter monsoon during the glacial ***,those local loess deposits should be identified as the“valley-sourced loess”.These reveal the inherent connection between the monsoon system and the loess deposits in Yangtze River Basin.

关键词： Yangtze River Basin Geochemistry Loess provenance Valley-sourced loess Loess Plateau

Effect of reduction pretreatments on PdAg/Al_(2)O_(3) for HCHO and CO oxidation

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2023年第2期124卷 371-378页

作者： Liwei Meng Xue Han lian yu Yafei Wang Beijing Institute of Petrochemical Technology Beijing 102617China General Research Institute for Non-Ferrous Metals Beijing 100088China

PdAg/Al_(2)O_(3) were pretreated by CO and H2 reduction pretreatments,*** reduced catalysts were tested for HCHO and CO oxidation and characterized by Brunner Emmet Teller(BET),X-ray diffraction(XRD),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS)and oxygen temperature programmed desorption(O_(2)-TPD).These results indicate that the pretreatments have effect on PdAg reconstruction,PdAg particle size and active oxygen species,which are responsible for the catalytic *** with H2 reduction method,CO reduction is more suitable for PdAg/Al_(2)O_(3) ***/Al_(2)O_(3)-CO exhibited better catalytic performance.

关键词： PdAg Reduction method Catalytic oxidation CO

Enhanced photocatalytic activity of rGO/TiO2 for the decomposition of formaldehyde under visible light irradiation

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2018年第11期30卷 138-146页

作者： lian yu Long Wang Xibo Sun Daiqi Ye College of Environment and Energy South China University of Technology Guangzhou 510006 China Cuangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control Guangzhou 510006 China National Engineering Laboratory for VOCs Pollution Control Technology and Equipment South China University of Technology Guangzhou 510006 China

Due to the low concentration of indoor air contaminants, photocatalytic technology shows low efficiency for indoor air purification. The application of TiO2 for photocatalytic removal of formaldehyde is limited, because TiO2 can only absorb ultraviolet （UV） light. Immobilization of TiO2 nanoparticles on the surface of graphene can improve the visible light photocatalytic activity and the adsorption capacity. In this study, rGO （reduced graphene oxide）/TiO2 was synthesized through a hydrotherrnal method using titanium tetrabutoxide and graphene oxide as precursors, and was used for the degradation of low concentration formaldehyde in indoor air under visible light illumination. Characterization of the crystalline structure and morphology of rGO/TiO2 revealed that most GO was reduced to rGO during the hydrothermal treatment, and anatase TiO2 nanoparticles （with particle size of 15-30 nm） were dispersed well on the surface of the rGO sheets, rGO/TiO2 exhibited excellent photocatalyfic activity for degradation of formaldehyde in indoor air and this can be attributed to the role ofrGO, which can act as the electron sink and transporter for separating photo-generated electron-hole pairs through interfacial charge transfer. Furthermore, rGO could adsorb formaldehyde molecules from air to produce a high concentration of formaldehyde on the surface of rGO/ TiO2. Under visible light irradiation for 240 min, the concentration of formaldehyde could be reduced to 58.5 ppbV. rGO/TiO2 showed excellent moisture-resistance behavior, and after five cycles, rGO/TiO2 maintained high photocatalytic activity for the removal of formaldehyde （84.6%）. This work suggests that the synthesized rGO/TiO2 is a promising photocatalyst for indoor formaldehyde removal.

关键词： Reduced graphene oxide (rGO) rGO/TiO2 nanocomposites Visible light photocatalysis Indoor air Formaldehyde

Influence of Lithium Oxide Addition on the Sintering Behavior and Electrical Conductivity of Gadolinia Doped Ceria

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2011年第5期27卷 460-464页

作者： Minfang Han Ze Liu Su Zhou lian yu Union Research Center of Fuel Cell School of Chemical & Environment Engineering University of Mining & Technology(CUMTB) Beijing 100083 China

Ceria-based electrolytes have been widely researched in intermediate-temperature solid oxide fuel cell （SOFC）, which might be operated at 500-600℃. Sintering behavior with lithium oxide as sintering additive and electrical conductivity of gadolinia doped ceria （GdonCe0.902-σ, GDC10） electrolyte was studied in this paper by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and electrochemical impedance spectroscopy （EIS）. As the results,, the fully dense GDC10 electrolytes are obtained at a low temperature of 800℃ with 2.5 mol% Li20 as sintering additive （called 5LiGDCS00）. During sintering process, lithium oxides adsorbed by around GDC10 surface help to sinter at 800~C and are kept at the grain boundary of GDC10 in the end. The fine grains of 100-400 nm and high electrical conductivity of 0.014 S/cm at 600~C in 5LiGDC800 were achieved, which contributed to the lower sintering temperature and enhanced grain boundary conductivity, respectively. Lithium, staying at grain boundary, reduces the depletion of oxygen vacancies in the space charge layers and increases the oxygen vacancy concentration in the grain boundary, which leads to improve the total electrical conductivity of 5LiGDC800.

关键词： Gadolinia doped ceria Sintering additive Electrical conductivity

Synthesis, UV-curing Behavior and Surface Properties of New Fluorine-containing Aromatic Oxetane Monomers

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2018年第4期36卷 521-527页

作者： Shu-Qing Fang yu-lian Pang Ying-Quan Zou College of Chemistry Beijing Normal University

In this paper, we combined high-end cationic UV-curable material with fluorinated chain obtaining a series of new fluorine-containing aromatic oxetane monomers via a mild nucleophilic substitution reaction. The structures and properties of monomers were characterized using ~1 H-NMR, ^（19） F-NMR, dynamic viscosity tests and differential scanning calorimetry（DSC）. It was determined that all of the fluorinated monomers obtained had much lower viscosity and higher thermostability after the introduction of hexafluorobenzene. Then, UV-curable coatings were prepared using four fluorine-containing aromatic oxetane monomers（FOX1-4）; the UV-curing kinetics, with three kinds of initiators, and properties of the cured films were evaluated using real-time Fourier transform infrared（FTIR） spectroscopy, water and diiodomethane contact angle tests, surface energy calculations and scanning electron microscopy（SEM）. The FTIR spectroscopy results showed that the coatings possessed excellent conversion rate（〉 99% with liquid initiator PAG-201 in 150 s）, and as the fluorine content increased, the monomers exhibited decreased mobility with the increasing viscosity and worse solubility with fluorinated monomers, resulting in a lower conversion rate. Moreover, the coatings possessed favorable hydrophobic and oleophobic properties and low surface energies owing to the fluoride chains floating to the membrane-air interface, which was also confirmed by discrete concave structures in SEM images. These new kinds of monomers can replace traditional fluorinated cationic monomers applied to the fingerprint resistant, fouling resistant, scratch resistant and anti-aging coatings, adhesives or printing ink materials.

关键词： Fluorine-containing monomers Oxetane UV-curing kinetics Surface properties

Acute pancreatitis associated left-sided portal hypertension with severe gastrointestinal bleeding treated by transcatheter splenic artery embolization:a case report and literature review

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2013年第6期14卷 549-554页

作者： Zhi-yu LI Bin LI yu-lian WU Qiu-ping XIE Department of Surgery the Second Affiliated HospitalSchool of MedicineZhejiang University

Left-sided portal hypertension(LSPH)followed by acute pancreatitis is a rare condition with most patients being *** cases where gastrointestinal(GI)bleeding is present,however,the condition is more complicated and the mortality is very high because of the difficulty in diagnosing and selecting optimal treatment.A successfully treated case with severe GI bleeding by transcatheter splenic artery embolization is reported in this *** patient exhibited severe uncontrollable GI bleeding and was confirmed as gastric varices secondary to LSPH by enhanced computed tomography(CT)scan and *** embolization,the bleeding stopped and stabilized for the entire follow-up period without any severe *** conclusion,embolization of the splenic artery is a simple,safe,and effective method of controlling gastric variceal bleeding caused by LSPH in acute pancreatitis.

关键词： Left-sided portal hypertension(LSPH) Gastric varices Acute pancreatitis Gastrointestinal bleeding Splenic artery embolization(SAE)