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Inter-stage performance and energy characteristics analysis of electric submersible pump based on entropy production theory
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作者 Hui Wang Yang Yang +5 位作者 Bin Xi Wei-Dong Shi Chuan Wang Lei-Lei Ji Xiang-Yu Song Zhao-Ming He 《Petroleum Science》 SCIE EI CAS CSCD 2024年第2期1354-1368,共15页
The electric submersible pump(ESP) is a crucial apparatus utilized for lifting in the oil extraction process.Its lifting capacity is enhanced by the multi-stage tandem structure, but variations in energy characteristi... The electric submersible pump(ESP) is a crucial apparatus utilized for lifting in the oil extraction process.Its lifting capacity is enhanced by the multi-stage tandem structure, but variations in energy characteristics and internal flow across stages are also introduced. In this study, the inter-stage variability of energy characteristics in ESP hydraulic systems is investigated through entropy production(EP) analysis,which incorporates numerical simulations and experimental validation. The EP theory facilitates the quantification of energy loss in each computational subdomain at all ESP stages, establishing a correlation between microscopic flow structure and energy dissipation within the system. Furthermore, the underlying causes of inter-stage variability in ESP hydraulic systems are examined, and the advantages and disadvantages of applying the EP theory in this context are evaluated. Consistent energy characteristics within the ESP, aligned with the distribution of internal flow structure, are provided by the EP theory, as demonstrated by our results. The EP theory also enables the quantitative analysis of internal flow losses and complements existing performance analysis methods to map the internal flow structure to hydraulic losses. Nonetheless, an inconsistency between the energy characterization based on EP theory and the traditional efficiency index when reflecting inter-stage differences is identified. This inconsistency arises from the exclusive focus of the EP theory on flow losses within the flow field, disregarding the quantification of external energy input to the flow field. This study provides a reference for the optimization of EP theory in rotating machinery while deeply investigating the energy dissipation characteristics of multistage hydraulic system, which has certain theoretical and practical significance. 展开更多
关键词 Electric submersible pump(ESP) Entropy production theory Energy characteristics Inter-stage differences
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Joint Optimization of Imperfect Preventive Maintenance and Production Scheduling for Single Machine Based on Game Theory Method
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作者 Zuhua Jiang Jiawen Hu +2 位作者 Hongming Zhou Peiwen Ding Jiankun Liu 《Journal of Harbin Institute of Technology(New Series)》 CAS 2023年第4期15-24,共10页
In this study,an optimization model of a single machine system integrating imperfect preventive maintenance planning and production scheduling based on game theory is proposed.The costs of the production department an... In this study,an optimization model of a single machine system integrating imperfect preventive maintenance planning and production scheduling based on game theory is proposed.The costs of the production department and the maintenance department are minimized,respectively.Two kinds of three-stage dynamic game models and a backward induction method are proposed to determine the preventive maintenance(PM)threshold.A lemma is presented to obtain the exact solution.A comprehensive numerical study is provided to illustrate the proposed maintenance model.The effectiveness is also validated by comparison with other two existed optimization models. 展开更多
关键词 game theory imperfect preventive maintenance production scheduling single machine system
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The Logical Premise and Methodological Basis of Marx’s Machine Production Theory
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作者 GAO Qin 《Journal of Philosophy Study》 2023年第5期214-219,共6页
Marx’s production paradigm constitutes the logical premise of his construction of machine production theory.Therefore,the machine production theory elaborated by Marx has a unique research method and theoretical pers... Marx’s production paradigm constitutes the logical premise of his construction of machine production theory.Therefore,the machine production theory elaborated by Marx has a unique research method and theoretical perspective,which is fundamentally different from other non-Marxist technical theories,which is also the basic starting point for understanding and explaining Marx’s machine production theory.By defining the logical premise of Marx’s machine production theory as production paradigm,we can not only reinterpret this theory based on the original context,but also examine the latest interaction between contemporary capitalism and technological reality on the basis of this interpretation.Only from the production paradigm can we truly grasp the complete connotation of“machine production”in Marx’s mature criticism of political economy. 展开更多
关键词 production paradigm machine production machine theory capitalist mode of production
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Hybrid data-driven framework for shale gas production performance analysis via game theory, machine learning, and optimization approaches 被引量:1
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作者 Jin Meng Yu-Jie Zhou +4 位作者 Tian-Rui Ye Yi-Tian Xiao Ya-Qiu Lu Ai-Wei Zheng Bang Liang 《Petroleum Science》 SCIE EI CAS CSCD 2023年第1期277-294,共18页
A comprehensive and precise analysis of shale gas production performance is crucial for evaluating resource potential,designing a field development plan,and making investment decisions.However,quantitative analysis ca... A comprehensive and precise analysis of shale gas production performance is crucial for evaluating resource potential,designing a field development plan,and making investment decisions.However,quantitative analysis can be challenging because production performance is dominated by the complex interaction among a series of geological and engineering factors.In fact,each factor can be viewed as a player who makes cooperative contributions to the production payoff within the constraints of physical laws and models.Inspired by the idea,we propose a hybrid data-driven analysis framework in this study,where the contributions of dominant factors are quantitatively evaluated,the productions are precisely forecasted,and the development optimization suggestions are comprehensively generated.More specifically,game theory and machine learning models are coupled to determine the dominating geological and engineering factors.The Shapley value with definite physical meaning is employed to quantitatively measure the effects of individual factors.A multi-model-fused stacked model is trained for production forecast,which provides the basis for derivative-free optimization algorithms to optimize the development plan.The complete workflow is validated with actual production data collected from the Fuling shale gas field,Sichuan Basin,China.The validation results show that the proposed procedure can draw rigorous conclusions with quantified evidence and thereby provide specific and reliable suggestions for development plan optimization.Comparing with traditional and experience-based approaches,the hybrid data-driven procedure is advanced in terms of both efficiency and accuracy. 展开更多
关键词 Shale gas production performance DATA-DRIVEN Dominant factors Game theory Machine learning Derivative-free optimization
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Heritage Communities in Consumer Contexts Spatial Production of Tourism Research-Take Qixian Zhao Yu Historical City as an Example
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作者 BAI Zhao-yi ZHU Jun-jie WEN Jia-hao 《Journal of Literature and Art Studies》 2024年第1期95-108,共14页
Taking Zhaoyu Historical City in Qixian County as an example,this paper explores the production process of tourism space in Zhaoyu Historical City in the context of consumption,based on Lefebvre's triadic dialecti... Taking Zhaoyu Historical City in Qixian County as an example,this paper explores the production process of tourism space in Zhaoyu Historical City in the context of consumption,based on Lefebvre's triadic dialectic theory.The study reveals that,driven by the development of tourism,subjects such as the government and planners possess absolute dominance over spatial representations,while residents demonstrate receptive and adaptive action strategies and social relations are reproduced,presenting a harmonious state.Further exploring the tourism community in the environmental performance of the subject of action,social relations,consumption demand,daily life practice,cultural capital,etc.,the daily life practice of the tourism community has transcended the original logic of tourism spatial production and has a certain extension.The mechanism analysis in this paper can help guide the healthy development of tourism space in the neighboring historical cities or communities and achieve the dual purpose of promoting the economic development of the community and heritage protection. 展开更多
关键词 spatial production theory tourism space consumption context heritage community ZhaoYu Historical City
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Game Theory Model and Equilibrium Analysis of Peasant's Production Decision 被引量:2
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作者 Qi Xue-lian Zhang Ya-zhuo Meng Jun 《Journal of Northeast Agricultural University(English Edition)》 CAS 2012年第2期71-73,共3页
Unbalanced agricultural production decision becomes the great block that influences the effective distribution of social resources, national grain security, social stability and economic development. This paper took t... Unbalanced agricultural production decision becomes the great block that influences the effective distribution of social resources, national grain security, social stability and economic development. This paper took the game theory as an analyzed tool to describe the interactional processes among the peasants, and set up the game theory model of independent decision and joint decision by peasants. It was shown that the government's positive guide and the market environment macroscopically controlled by the government could effectively increased the peasants' income 展开更多
关键词 agricultural production decision game theory Nash equilibrium
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Effect of radiolysis of TODGA on the extraction of TODGA/n-dodecane toward Eu(Ⅲ):an experimental and DFT study 被引量:1
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作者 Hang Zhang Yin-Yong Ao +6 位作者 Yue Wang Shang-Jie Zhao Jia-Yang Sun Mao-Lin Zhai Jiu-Qiang Li Jing Peng Hui-Bo Li 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2023年第4期1-13,共13页
N,N,N′,N′-Tetraoctyl diglycolamide(TODGA)is one of the most promising extractants tailored for high-level liquid radioactive waste treatment during nuclear fuel reprocessing.Theγ-radiolysis of TODGA(0.2 mol/L)in n-... N,N,N′,N′-Tetraoctyl diglycolamide(TODGA)is one of the most promising extractants tailored for high-level liquid radioactive waste treatment during nuclear fuel reprocessing.Theγ-radiolysis of TODGA(0.2 mol/L)in n-dodecane(n DD)solution with and without pre-equilibrated 3.0 mol/L HNO_(3)was investigated using HPLC and UPLC-QTOF-MS and compared with theγ-radiolysis of neat TODGA in this study.With increased absorbed doses,the concentration of TODGA decreased exponentially for the studied systems.Moreover,pre-equilibration with HNO_(3)(3.0 mol/L)slightly influenced theγ-radiolysis of TODGA in n DD.Seven radiolytic products generated from the rupture of the C–C,C–O,and C–N bonds in TODGA were identified in the studied extraction system.The influence ofγ-radiation on TODGA/n DD for the extraction of Eu(Ⅲ)was evaluated using the first combination of extraction experiments and density functional theory(DFT)calculations,in which the complexations of Eu(Ⅲ)with TODGA and its radiolytic products were systematically compared.Based on the radiolysis kinetic model of TODGA,the slope curve of the distribution ratio of Eu(Ⅲ)(D_(Eu))and the absorbed dose,and fluorescence titration analysis,the empirical equation of the absorbed dose and D_(Eu)was obtained successfully.Below 300 kGy,the experimental D_(Eu)agreed well with the obtained empirical equation for TODGA/n DD.Conversely,at a high absorbed dose,the experimental D_(Eu)was higher than the theoretical D_(Eu)based on the empirical equation because the radiolytic products of TODGA with similar coordination structures still possessed partial complexation toward Eu(Ⅲ),which was confirmed by DFT calculations.This work provides a method to predict the extraction distribution ratio of an irradiated extractant system and to understand the complex extraction process. 展开更多
关键词 TODGA Radiolytic products EXTRACTION Density functional theory COMPLEXATION
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“Extreme utilization” theory and practice in gas storages with complex geological conditions 被引量:1
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作者 MA Xinhua ZHENG Dewen +1 位作者 DING Guosheng WANG Jieming 《Petroleum Exploration and Development》 SCIE 2023年第2期419-432,共14页
Based on more than 20-year operation of gas storages with complex geological conditions and a series of research findings, the pressure-bearing dynamics mechanism of geological body is revealed. With the discovery of ... Based on more than 20-year operation of gas storages with complex geological conditions and a series of research findings, the pressure-bearing dynamics mechanism of geological body is revealed. With the discovery of gas-water flowing law of multi-cycle relative permeability hysteresis and differential utilization in zones, the extreme utilization theory targeting at the maximum amount of stored gas, maximum injection-production capacity and maximum efficiency in space utilization is proposed to support the three-in-one evaluation method of the maximum pressure-bearing capacity of geological body, maximum well production capacity and maximum peak shaving capacity of storage space. This study realizes the full potential of gas storage(storage capacity) at maximum pressure, maximum formation-wellbore coordinate production, optimum well spacing density match with finite-time unsteady flow, and peaking shaving capacity at minimum pressure, achieving perfect balance between security and capacity. Operation in gas storages, such as Hutubi in Xinjiang, Xiangguosi in Xinan, and Shuang6 in Liaohe, proves that extreme utilization theory has promoted high quality development of gas storages in China. 展开更多
关键词 underground gas storage gas-storage geological body maximum pressure-bearing maximum well production capacity maximum peak shaving capacity extreme utilization theory multi-cycle relative permeability hysteresis
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Theory and application research development of semi-solid forming in China 被引量:15
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作者 罗守靖 姜永正 康永林 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第9期1805-1814,共10页
In order to adapt to the trend of "energy saving and emission reduction" and impel the practical application of semi-solid processing (SSP) in China, the progress and application of semi-solid theory in Chin... In order to adapt to the trend of "energy saving and emission reduction" and impel the practical application of semi-solid processing (SSP) in China, the progress and application of semi-solid theory in China have been reviewed briefly and systematically.It was emphasized on basic theories, such as formation of globular grains, rheology, high pressure solidification and plastic deformation and applications, such as material design, preparation of semi-solid billets (slurries), thixoforming and application status, which are based on the advantage of semi-solid processing.The results show that the gap of SSP between world level and China exists, especially in application technologies, including market recognition, application fields exploiting, developing of billets (slurries) preparation technologies with low cost and special equipments.The prospect of semi-solid forming development path in China is presented.And we hope that application of SSP has great new breakthrough and development and China will be changed from a large metal processing country to a powerful metal processing country. 展开更多
关键词 半固态成形 应用 中国 过磷酸钙 制备技术 金属加工 半固态加工 固体理论
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Design Theory and Method of Complex Products:A Review 被引量:1
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作者 Chan Qiu Jianrong Tan +2 位作者 Zhenyu Liu Haoyang Mao Weifei Hu 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2022年第5期1-16,共16页
Design is a high-level and complex thinking activity of human beings,using existing knowledge and technology to solve problems and create new things.With the rise and development of intelligent manufacturing,design ha... Design is a high-level and complex thinking activity of human beings,using existing knowledge and technology to solve problems and create new things.With the rise and development of intelligent manufacturing,design has increasingly reflected its importance in the product life cycle.Firstly,the concept and connotation of complex product design is expounded systematically,and the different types of design are discussed.The four schools of design theory are introduced,including universal design,axiomatic design,TRIZ and general design.Then the research status of complex product design is analyzed,such as innovative design,digital design,modular design,reliability optimization design,etc.Finally,three key scientific issues worthy of research in the future are indicated,and five research trends of“newer,better,smarter,faster,and greener”are summarized,aiming to provide references for the equipment design and manufacturing industry. 展开更多
关键词 Product design Design theory and method Innovative design Digital design
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Detecting a Regularity in the Generation and Utilization of Primes in the Multiplicative Number Theory 被引量:2
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作者 Silviu Guiasu 《Natural Science》 2019年第6期187-196,共10页
If Goldbach’s conjecture is true, then for each prime number p there is at least one pair of primes symmetric with respect to p and whose sum is 2p. In the multiplicative number theory, covering the positive integers... If Goldbach’s conjecture is true, then for each prime number p there is at least one pair of primes symmetric with respect to p and whose sum is 2p. In the multiplicative number theory, covering the positive integers with primes, during the prime factorization, may be viewed as being the outcome of a parallel system which functions properly if and only if Euler’s formula of the product of the reciprocals of the primes is true. An exact formula for the number of primes less than or equal to an arbitrary bound is given. This formula may be implemented using Wolfram’s computer package Mathematica. 展开更多
关键词 Goldbach’s CONJECTURE Symmetric Prime Cousins Systemic Approach in NUMBER theory Parallel System Covering INTEGERS with PRIMES Euler’s FORMULA for the Product of Reciprocals of PRIMES FORMULA for the Exact NUMBER of PRIMES Less than or Equal to an Arbitrary Bound
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Applied methods for studying the relationship between climatic factors and cotton production 被引量:1
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作者 Zakaria M. Sawan 《Agricultural Sciences》 2013年第11期37-54,共18页
This study investigates the statistical relationship between climatic variables and aspects of cotton production (G. barbadense), and the effects of climatic factors prevailing prior to flowering or subsequent to boll... This study investigates the statistical relationship between climatic variables and aspects of cotton production (G. barbadense), and the effects of climatic factors prevailing prior to flowering or subsequent to boll setting on flower and boll production and retention in cotton. The effects of specific climatic factors during both pre-?and post-anthesis periods on boll production and retention are mostly unknown. However, by determining the relationship of climatic factors with flower and boll production and retention, the overall level of production can be possibly predicted. Thus, an understanding of these relationships may help physiologists determine control mechanisms of production in cotton plants. Also, the study covers the predicted effects of climatic factors during convenient intervals (in days) on cotton flower and boll production compared with daily observations. Further, cotton flower and boll production as affected by climatic factors and soil moisture status has been considered. Evaporation, sunshine duration, relative humidity, surface soil temperature at 1800 h, and maximum air temperature, are the important climatic factors that significantly affect flower and boll production. The least important variables were found to be surface soil temperature at 600 h and minimum temperature. The five-day interval was found to be more adequately and sensibly related to yield parameters. Evaporation, minimum humidity and sunshine duration were the most effective climatic factors during preceding and succeeding periods on boll production and retention. There was a negative correlation between flower number and boll production and either evaporation or sunshine duration, while that correlation with minimum relative humidity was positive. The soil moisture status showed low and insignificant correlation with flower and boll production. Higher minimum relative humidity, short period of sunshine duration, and low temperatures enhanced flower and boll formation. 展开更多
关键词 Cotton FLOWER and Boll production Boll RETENTION EVAPORATION Relative Humidity Soil Moisture Status SUNSHINE DURATION Temperature
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High-rate electrochemical H_(2)O_(2) production over multimetallic atom catalysts under acidic–neutral conditions
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作者 Yueyu Tong Jiaxin Liu +5 位作者 Bing-Jian Su Jenh-Yih Juang Feng Hou Lichang Yin Shi Xue Dou Ji Liang 《Carbon Energy》 SCIE EI CAS CSCD 2024年第1期44-62,共19页
Hydrogen peroxide(H_(2)O_(2))production by the electrochemical 2-electron oxygen reduction reaction(2e−ORR)is a promising alternative to the energy-intensive anthraquinone process,and single-atom electrocatalysts show... Hydrogen peroxide(H_(2)O_(2))production by the electrochemical 2-electron oxygen reduction reaction(2e−ORR)is a promising alternative to the energy-intensive anthraquinone process,and single-atom electrocatalysts show the unique capability of high selectivity toward 2e−ORR against the 4e−one.The extremely low surface density of the single-atom sites and the inflexibility in manipulating their geometric/electronic configurations,however,compromise the H_(2)O_(2) yield and impede further performance enhancement.Herein,we construct a family of multiatom catalysts(MACs),on which two or three single atoms are closely coordinated to form high-density active sites that are versatile in their atomic configurations for optimal adsorption of essential*OOH species.Among them,the Cox–Ni MAC presents excellent electrocatalytic performance for 2e−ORR,in terms of its exceptionally high H_(2)O_(2) yield in acidic electrolytes(28.96 mol L^(−1) gcat.^(−1) h^(−1))and high selectivity under acidic to neutral conditions in a wide potential region(>80%,0–0.7 V).Operando X-ray absorption and density functional theory analyses jointly unveil its unique trimetallic Co2NiN8 configuration,which efficiently induces an appropriate Ni–d orbital filling and modulates the*OOH adsorption,together boosting the electrocatalytic 2e−ORR capability.This work thus provides a new MAC strategy for tuning the geometric/electronic structure of active sites for 2e−ORR and other potential electrochemical processes. 展开更多
关键词 hydrogen peroxide production multiatom catalysts operando X-ray adsorption spectrum reaction mechanism tendency structure-property relation
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Shale oil development techniques and application based on ternary-element storage and flow concept in Jiyang Depression,Bohai Bay Basin,East China
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作者 YANG Yong 《Petroleum Exploration and Development》 SCIE 2024年第2期380-393,共14页
The ternary-element storage and flow concept for shale oil reservoirs in Jiyang Depression of Bohai Bay Basin,East China,was proposed based on the data of more than 10000 m cores and the production of more than 60 hor... The ternary-element storage and flow concept for shale oil reservoirs in Jiyang Depression of Bohai Bay Basin,East China,was proposed based on the data of more than 10000 m cores and the production of more than 60 horizontal wells.The synergy of three elements(storage,fracture and pressure)contributes to the enrichment and high production of shale oil in Jiyang Depression.The storage element controls the enrichment of shale oil;specifically,the presence of inorganic pores and fractures,as well as laminae of lime-mud rocks,in the saline lake basin,is conducive to the storage of shale oil,and the high hydrocarbon generating capacity and free hydrocarbon content are the material basis for high production.The fracture element controls the shale oil flow;specifically,natural fractures act as flow channels for shale oil to migrate and accumulate,and induced fractures communicate natural fractures to form complex fracture network,which is fundamental to high production.The pressure element controls the high and stable production of shale oil;specifically,the high formation pressure provides the drive force for the migration and accumulation of hydrocarbons,and fracturing stimulation significantly increases the elastic energy of rock and fluid,improves the imbibition replacement of oil in the pores/fractures,and reduces the stress sensitivity,guaranteeing the stable production of shale oil for a long time.Based on the ternary-element storage and flow concept,a 3D development technology was formed,with the core techniques of 3D well pattern optimization,3D balanced fracturing,and full-cycle optimization of adjustment and control.This technology effectively guides the production and provides a support to the large-scale beneficial development of shale oil in Jiyang Depression. 展开更多
关键词 Jiyang Depression continental shale oil reservoir space fracturing stimulation fracture network storage and flow theory 3D development high and stable production
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Short Communication: Enhancing the Drying Process of Microbial-Based Products with a Dehumidifier
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作者 Nor Hidayah Bohari Elya Masya Mohd Fishal +2 位作者 Ili Bazilah Abd Razak Muhammad Ashraf Arif Mohd Nasir Cik Mohd Rizuan Zainal Abidin 《Advances in Microbiology》 CAS 2024年第6期333-339,共7页
The development of microbial-based products requires certain criteria for them to be successfully commercialized. The product must meet the following desirable criteria: effectiveness, contamination free, stability, c... The development of microbial-based products requires certain criteria for them to be successfully commercialized. The product must meet the following desirable criteria: effectiveness, contamination free, stability, cost-effectiveness, and a prolonged shelf life. Controlling the drying process is crucial for ensuring the stability and durability of the product. The traditional approach, which involved mechanical and natural drying, led to decreased productivity and quality. The objective of this research endeavour was to achieve a dry process enhancement while preserving the microbial quality of Trichoderma asperellum (M103). The temperature and relative humidity during the drying period were monitored under two conditions: with and without a dehumidifier. The results demonstrate that the dehumidifier increases drying period efficiency by up to 63%. 展开更多
关键词 DEHUMIDIFIER DRYING Relative Humidity Microbial-Based Product
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Research on the Problem of Art Production Theory Since the New Period
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作者 JIA Fu-rui 《Journal of Literature and Art Studies》 2020年第12期1192-1196,共5页
The issue of art production is an important topic discussed in China’s academia. The article first discusses thetheoretical issues of early art production in China, mainly taking Mr. Dong Xuewen’s views as an exampl... The issue of art production is an important topic discussed in China’s academia. The article first discusses thetheoretical issues of early art production in China, mainly taking Mr. Dong Xuewen’s views as an example. Second,scholars have their own views on the discussion of the unbalanced development of art production and materialproduction in the 1970s and 1980s. Third, this article uses the art production theory to construct the contemporaryliterary art form, and raises the art production theory to the essentialism to discuss the art production theory and thereflection theory. Fourth, the relationship between art production and art consumption is in large-scalecomprehensive systematic research. 展开更多
关键词 art production theory material production reflection theory art consumption
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Statistical Study: Nature Relationship between Climatic Variables Prevailing Prior to Flowering or Subsequent to Boll Setting and Cotton Production
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作者 Zakaria M. Sawan 《Natural Science》 2014年第8期583-596,共14页
This study investigates the statistical relationship between climatic variables and aspects of cotton production (G. barbadense), and the effects of climatic factors prevailing prior to flowering or subsequent to boll... This study investigates the statistical relationship between climatic variables and aspects of cotton production (G. barbadense), and the effects of climatic factors prevailing prior to flowering or subsequent to boll setting on flower and boll production and retention in cotton. The effects of specific climatic factors during both pre- and post-anthesis periods on boll production and retention are mostly unknown. Thus, an understanding of these relationships may help physiologists to determine control mechanisms of production in cotton plants. Evaporation, sunshine duration, relative humidity, surface soil temperature at 1800 h, and maximum air temperature, are the important climatic factors that significantly affect flower and boll production. The least important variables were found to be surface soil temperature at 0600 h and minimum temperature. There was a negative correlation between flower and boll production and either evaporation or sunshine duration, while that correlation with minimum relative humidity was positive. Higher minimum relative humidity, short period of sunshine duration, and low temperatures enhanced flower and boll formation. 展开更多
关键词 Cotton FLOWER and Boll production Boll RETENTION EVAPORATION Relative Humidity SUNSHINE DURATION Temperature
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The “productivity paradox” of Chinese export firms: Review and assessment 被引量:4
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作者 李春顶 尹翔硕 《China Economist》 2010年第2期74-82,共9页
This paper represents an attempt to test the relationship between the exports and productivity of Chinese firms using the data set of nearly 3 million industrial firms in 20 industrial sectors over the period 1998-200... This paper represents an attempt to test the relationship between the exports and productivity of Chinese firms using the data set of nearly 3 million industrial firms in 20 industrial sectors over the period 1998-2007. Our test finds that non-export firms were more productive than export firms, and exports were negatively related to productivity-namely that the lower the productivity of a firm, the higher its exports. This finding is in contradiction with the hypothesis of new-new trade theory. The contradiction is referred to as the "productivity paradox" in this paper. Further tests find that firm size is a key factor affecting firm exports, but the impact of exports on firm productivity is insignif icant. This paper reckons that the "productivity paradox" of Chinese export firms may be attributed to the disproportionate share of processing trade in export trade. 展开更多
关键词 New-new TRADE theory FIRM HETEROGENEITY productivity EXPORT TRADE
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Co-integration Analysis of the Relationship between New Product Output and R&D Investment in China’s Pharmaceutical Industry
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作者 Li Gan Wang Su Chen Yuwen 《Asian Journal of Social Pharmacy》 2022年第4期309-316,共8页
Objective To study the possible relationship between the output of new products in China’s pharmaceutical industry and the investment in research and development(R&D),and to provide a theoretical basis for the de... Objective To study the possible relationship between the output of new products in China’s pharmaceutical industry and the investment in research and development(R&D),and to provide a theoretical basis for the decision-making of relevant enterprises and institutions.Methods The econometric software Stata 14 was used to perform unit root test on the relevant data.Then,a co-integration regression equation was established after stabilization,which was analyzed through co-integration test(E-G two-step method).Results and Conclusion There is a long-term equilibrium and short-term error correction relationship between the output of new products and the investment of R&D funds in China’s pharmaceutical industry.During the lagging periods from 1 to 6,R&D investment is the Granger reason for the output of new products.The investment of R&D funds has a positive effect on the output of new products and the effect is significant.Therefore,more investment should be made in R&D to enhance the output of new products. 展开更多
关键词 pharmaceutical production R&D input new product output co-integration theory
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Research and Development of Skincare Products Based on the Theory of Traditional Chinese Medicine
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作者 Li Li Wang Weilian +3 位作者 Meng Xianyao Yi Fan Wang Kezhen Yan Xinyue 《China Detergent & Cosmetics》 2022年第3期21-26,共6页
The application of traditional Chinese medicine in skincare formula development was expounded from the views of“symptom,theory,method,prescription,medicine and effect”.Traditional Chinese medicine prescriptions were... The application of traditional Chinese medicine in skincare formula development was expounded from the views of“symptom,theory,method,prescription,medicine and effect”.Traditional Chinese medicine prescriptions were improved according to the laws and regulations for China’s cosmetic industry and by the modern scientific and technological means,which had important guiding significance for the research and development of plant-based functional skincare products.The problems in concept claim and quality control standard,and the problems of market confusion,which were ascribed to the lack of basic research in the application of Chinese herbal cosmetics,were pointed out.The future development direction of plant-based functional cosmetics guided by TCM theory was prospected. 展开更多
关键词 TCM theory Chinese medicinal formulae vegetable origin plant functional skincare product
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