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Fuel cell is a new type of energy conversion device using hydrogen，methanol，etc. as fuel，among which the proton exchange membrane fuel cell（PEMFC）has been widely used in mobile power，submarines and electric vehicles by virtue of its high energy power，fast start-up speed and long service life. Proton exchange membranes（PEM）have the greatest impact on the performance of PEMFC. Efficient PEMFC requires PEM with high proton conductivity，good thermal stability and mechanical properties，low fuel permeability and excellent physical and chemical stability. Most of the membranes currently used in the market are Nafion membranes with excellent proton conductivity，but they have disadvantages such as difficulty in preparation， expensive cost，and heavy dependence on humidity for proton conductivity，which limits their development to some extent. In order to make more options for proton exchange membranes，scientists have been focusing on using new materials to replace Nafion membranes. In recent years，scientists have simulated the Nafion structure by synthesizing various side chain polyaryl ether structures containing sulfonic acid groups，allowing the formation of microphase separation structures between hydrophilic sulfonic acid groups and hydrophobic groups，resulting in a series of proton exchange membranes with excellent overall performance. This paper focuses on the synthesis methods and properties of several common strategies，such as side chain alkyl sulfonated type，side chain sulfonated block type，side chain partially dense sulfonated type，side chain sulfonated cross-linked type and side chain sulfonated composite type. Finally，the advantages and development prospects of side chain sulfonated polyaryl ethers in the field of proton exchange membranes are reviewed. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Jilin University (Science Edition) / Jilin Daxue Xuebao (Lixue Ban) is the property of Zhongguo Xue shu qi Kan (Guang Pan Ban) Dian zi Za zhi She and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Commerce & Management Quarterly is the property of Chinese Association of Business & Management Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Beijing University of Technology is the property of Journal of Beijing University of Technology, Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Jilin University (Science Edition) / Jilin Daxue Xuebao (Lixue Ban) is the property of Zhongguo Xue shu qi Kan (Guang Pan Ban) Dian zi Za zhi She and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Systems Engineering & Electronics is the property of Journal of Systems Engineering & Electronics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: To explore the therapeutic effect of plasma exchange and platelet transfusion on idiopathic thrombocytopenic purpura. Methods: 60 patients with idiopathic thrombocytopenic purpura who were treated in our hospital from February 2016 to January 2019 were selected as the research object, and they were divided into platelet transfusion group (20 cases) and plasma according to the difference in treatment options In the Plasma exchange (PE) group (40 cases), the treatment efficiency, changes in blood cell counts before and after treatment, and the occurrence of various adverse reactions during treatment were compared between the two groups. Results: In the platelet transfusion group, there were 10 cases of effective treatment, 6 effective cases, and the total effective rate was 80.00 %. In the PE group, there were 27 cases of effective treatment, 12 effective cases, and the total effective rate was 97.50 %. The difference is obvious(P<0.05). Compared with before treatment, the PLT, RBC count and Hb levels of PE patients increased significantly, the WBC count decreased significantly (P<0.05), and the PLT, RBC count and Hb levels of platelet transfusion group also increased significantly High, the WBC count level decreased (P<0.05), but the comparison between the groups showed that the above indexes of the PE group after treatment were better than the platelet transfusion group (P<0.05). The total number of adverse reactions in the platelet transfusion group was 4 and the total incidence of adverse reactions was 20.00%. The total number of adverse reactions in the PE group was 3 and the total incidence of adverse reactions was 7.50%. Lower than platelet transfusion group (P<0.05). Conclusion: Platelet transfusion and plasma exchange have a good therapeutic effect on idiopathic thrombocytopenic purpura, which can significantly improve the patient's abnormal blood cell count, but plasma exchange treatment is more safe. [ABSTRACT FROM AUTHOR]

To the in conformity that the assumption of constant volatility in the traditional Black Scholes model is not consistent with the real financial market, the G-Brownian motion was used to describe the changes of the stock price and establish the financial market mathematical model. The sliding window method was used to estimate the upper and lower variance, the relevant theories of G-Brownian motion and the definition were used to simulate the underlying asset price. The Monte Carlo method was used to simulate the price of the embedded call option of the convertible bond, and the convertible bond is further priced. The empirical analysis was made through the data of Changzheng convertible bond transactions, and compared with the pricing results of the traditional Black-Scholes model. The results show that the financial market model in the G-Brownian motion environment is more adapted to the real financial market than the traditional Black-Scholes model. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Water option trading aims at solving the problem of uneven spatial and temporal distribution of water resources. With the change of global climate, rainfall has become an important factor leading to the uneven spatial and temporal distribution of water resources. In this paper, Markov chain is used to divide and forecast the rainfall scenarios. On the basis of rainfall forecast, the related costs of water option trading are determined. The forecast results of rainfall index are integrated into the determination of the ultimate overprice of water options. The improved Black- Scholes option pricing model is used to determine the rights of water options trading based on the forecast results of rainfall. Finally, the rationality of the calculation results is verified by using the extended linear expenditure model, which proves the rationality of the transaction price determined by the model. Taking Guangdong province as an example, this paper verifies the necessity of incorporating rainfall index into water option trading and the rationality of the related costs of water option trading determined by the model, and proves the superiority of fluctuating water price over stepped water price. Water option trading considering rainfall fully reflects the relationship between supply and demand in water market, and improves the scientificity of water option trading pricing in China. [ABSTRACT FROM AUTHOR]

This paper studies the hedging error of foreign exchange options. In respect of the typical static and dynamic Delta hedging strategies, under the circumstance of incomplete market, in which hedging process is discontinuous and interest rate parity theory is not established, the hedging error formulas of spot hedging and forward hedging are given, which can be used to measure the risk of actual hedging portfolio more accurately. In the process of studying Delta hedging strategies, this paper presents a forward exchange rate model including the friction coefficient ε. And by analyzing the difference between the spot hedging and forward hedging, a criterion for choosing the optimal hedging method is given. The criterion depends on the friction coefficient ε, so the market maker can choose the optimal risk hedging method only through real-time monitoring of friction coefficient ε, thus improving the hedging efficiency. The specific analytic formula of hedging error and the criterion of optimal hedging method proposed in this paper provide theoretical basis for foreign exchange option hedging and its risk management. The empirical results show that, the expected return difference proposed in this paper is basically consistent with the actual hedging portfolio, which verifies the rationality of the criterion. [ABSTRACT FROM AUTHOR]

Taking into account the features of logistics, this paper discusses the key elements constituting the competence of modern logistics firms and defines them in terms of a collection of organizational routines. The core competence of logistics firms comes from the combination of operational capability and absorptive capacity (AC). Operational capability is the basic capability of sustaining the survival of a firm. It consists of 4 sub-capabilities (market identification & development capability, service management capability, technological innovation capability and network organizing capability) together with a collection of organizational routines and relevant resources. As a higher-level capability with strategic flexibility for resource re-deployment and reorganization of routines, absorptive capacity consists of two components, namely internal and external AC capabilities. The competence of a logistics firm results from the combination of organizational routines and the resources they control at three levels: individual, operational and managerial. Research indicates that the evolution of the competence of a logistics firm, with absorptive capacity as its dominant factor, is a process during which a firm actively seeks for the variation of the routines so as to facilitate the upgrading of its capabilities. During the process, absorptive capacity plays an important role of guiding the evolution of operational capability and promoting the upgrading of the capabilities at different levels. This includes the processes of the triggering of routine, the input of new knowledge, routine variation, multi-level selection, the retention and upgrading of capabilities, and so on. Among them, external absorptive capacity dominates the input of new knowledge which is gained from the multi-level knowledge sharing pipelines in the routine interactions between the leading logistics firms and enterprise partners in the supply chain. The pipelines provide an access to the value-added knowledge of targeted customers. The new ideas and thoughts, generated by the input of new knowledge and guided by the routines of internal absorptive capacity, will lead to variations after being integrated with the existing routines of sub-capabilities and produce new routines or new sub-routines. This part of routine innovation is achieved by the participation of all the sub-capabilities of operational capability with a focus on customer value creation. As a result, new products and services options are created. However, the new products and service options are subject to the systematic routine selection process in a firm. It has been proved that when it comes to sustainable growth, logistics firms find it hard to strike a balance between customer satisfaction and investment cost. The enhancement of one sub-capability does not necessarily produce a positive correlation with operational capability. The verification of synergetic cost acts as the main solution to this problem. The new routine must undergo the synergistic effect test involving the four sub-capabilities as it is a cross-sector, multi-level systematic selection process, in which the management sector plays a crucial role. Obviously, the creation of new products and new services needs to be accompanied by the improved operational procedures and networks. Consequently, one variation of an important routine might cause the variation of the whole collection of one sub-capability, and the desired generation of synergy effect among all its new sub-capabilities literally leads to the substantial enhancement of the operational capability of logistics firms. In conclusion, the creation of new routines needs to go through the "synergistic effect' verification and "strategic fit" test by means of multi-level selection in the real world. [ABSTRACT FROM AUTHOR]

he paper established a utility function of containing the surplus risk and shortage risk to find the impacts on the supply chain coordination given different risk preference. By comparing the coordination strategies about return policy and option contracts given the agents being risk-neutrality or risk-averse, it gives the optimal prices of buyback contracts and option contracts and approach the following results: 1) In option contracts, the manufacturer does not need to guess the risk attitude of the retailer. 2) Whatever the risk attitude is, there is a rule that the higher the controlling coefficient is, the better coordination is, the more profit is. 3) Given the risk-averse agents it shows that the profit of the centralized supply chain is not affirmatively higher than the profit of decentralized supply chain. Therefore, with the risk-averse agents various coordinated policies show distinct effects. It also provides important methods for the similar research. [ABSTRACT FROM AUTHOR]

Moving window Parisian options are higher level of complicated Parisian options, they are widely used in the convertible bonds and so on. In the continuous time framework, this paper expands the Anderluh's method, presents the pricing formula, the algorithm and algorithm realized based on the ; hitting time simulation of moving window Parisian options. According this method, we compare the prices of cumulative Parisian options, consecutive Parisian options and moving window Parisian options with different parameters. Results show that the method is efficient. Finally, in order to verify the precision of the simulation, we compare the hitting time simulation algorithm and standard Monte Carlo algorithm employing barrier options (degenerate Parisian option) as a benchmark, which shows the hitting time simulation algorithm has higher precision. This method will improve the accuracy of the valuation of the convertible bonds, and provide a valuable basis for convertible bonds issuance and investment decisions in China. [ABSTRACT FROM AUTHOR]

Considering the more and more regular and fierce market competition and especially the tremendous development of shipping derivative market in recent years, a method of dynamic pricing decision-making of service contracts for international container ocean shipping based on option theory, with prices as external variables, was put forward. A model with American put/call options and complying with the current legal regime was built for dynamic pricing decision-making of service contracts for international container ocean shipping. On the basis of Ito Lemma and its properties concerned, the model was solved through transferring relevant differential equations. Based on certain numerical examples, the obtaining and estimation method of key parameters was described in detail. The affecting mechanism of relevant factors involved in service contracts with American call/put options was analyzed by solving the numerical examples; meanwhile, the effectiveness of the model was testified. [ABSTRACT FROM AUTHOR]

This paper deals with the stochastic volatility option pricing model in the viewpoint of Knightian uncertainty. First, we prove that the stochastic volatility model is in fact a Knightian uncertainty model; and we use the discounted relative entropy to measure the Knighitan uncertainty. Then, having balanced the Knightian uncertainty and Knightian premium through a utility function, we get the optimum probability measure, and we get the price formula of European call option with Knightian aversion degree γ. We find that γ and expiration date have important effect on the price of option by Monte Carlo simulation, and we give an example to show how to estimate the values of γ. [ABSTRACT FROM AUTHOR]