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Numerical study on laminar flame speed of natural gas-carbon monoxide-air mixtures

Chen DONG, Qulan ZHOU, Qinxin ZHAO, Tongmo XU, Shi’en HUI

《化学科学与工程前沿（英文）》 2010年 第4卷 第4期   页码 411-416 doi: 10.1007/s11705-010-0514-9

摘要： Laminar flame speeds of natural gas-carbon monoxide-air mixtures are calculated by CHEMKIN II with GRI Mech-3.0 over a large range of fuel compositions, equivalence ratios, and initial temperatures. The calculated results of natural gas are compared with previous experimental results that show a good agreement. The calculated laminar flame speeds of natural gas-carbon monoxide-air mixtures show a nonmonotonic increasing trend with volumetric fraction of carbon monoxide and an increasing trend with the increase of initial temperature of mixtures. The maximum laminar flame speed of certain fuel blend reaches its biggest value when there is 92% volumetric fraction of carbon monoxide in fuel at different initial temperatures. Five stoichiometric natural gas-carbon monoxide-air mixtures are selected to study the detailed chemical structure of natural gas-carbon monoxide-air mixtures. The results show that at stoichiometric condition, the fuel blend with 80% volumetric fraction of carbon monoxide has the biggest laminar flame speed, and the C normalized total production rate of methane with 80% volumetric fraction of carbon monoxide is the largest of the five stoichiometric mixtures.

关键词： laminar flame speed     numerical study     nonmonotonic increasing trend    

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Study on reformulation of fluid catalytic cracking gasoline and increasing production of light olefins

YAN Pingxiang, MENG Xianghai, GAO Jinsen, XU Chunming, SUI Zhiyu

《化学科学与工程前沿（英文）》 2008年 第2卷 第1期   页码 74-79 doi: 10.1007/s11705-008-0016-1

摘要： The effects of reaction temperature, mass ratio of catalyst to oil, space velocity, and mass ratio of water to oil on the product distribution, the yields of light olefins (light olefins including ethylene, propylene and butylene) and the composition of the fluid catalytic cracking (FCC) gasoline upgraded over the self-made catalyst GL in a confined fluidized bed reactor were investigated. The experimental results showed that FCC gasoline was obviously reformulated under appropriate reaction conditions. The olefins (olefins with C atom number above 4) content of FCC gasoline was markedly reduced, and the aromatics content and octane number were increased. The upgraded gasoline met the new standard of gasoline, and meanwhile, higher yields of light olefins were obtained. Furthermore, higher reaction temperature, higher mass ratio of catalyst to oil, higher mass ratio of water to oil, and lower space velocity were found to be beneficial to FCC gasoline reformulation and light olefins production.
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Influence of increasing numbers of RE-inverters on the power quality in the distribution grids: A PQ

Przemyslaw JANIK, Grzegorz KOSOBUDZKI, Harald SCHWARZ

《能源前沿（英文）》 2017年 第11卷 第2期   页码 155-167 doi: 10.1007/s11708-017-0469-3

摘要： This paper presents the selected power quality (PQ) indicia of a wind generator and a photovoltaic installation considered to be the representative of medium voltage and low voltage distribution grids. The analysis of measured values suggests that the decrease in PQ is a case of specific combination of distributed generation, grid parameters and load behaviour. Modern generators have a limited impact on PQ. On the other hand, fluctuations in power generation are regarded as an emerging PQ indicator. The growing number of distributed renewable installations causes stochastic, variable, and hardly predictable power flows in the distribution grid. The nature of fluctuations in wind and solar generation is different. In both cases, new indexes for the quantification of fluctuations are needed and are yet not standardised. Proper assessment of these fluctuations enables definition of useful fluctuation limits and rules for optimal storage system integration.

关键词： power quality     harmonics     sags     photovoltaic(PV) system     doubly feed induction generator (DFIG)     inverters    

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Breeding strategies for increasing yield potential in super hybrid rice

Shihua CHENG,Xiaodeng ZHAN,Liyong CAO

《农业科学与工程前沿（英文）》 2015年 第2卷 第4期   页码 277-282 doi: 10.15302/J-FASE-2015081

摘要： Super hybrid rice breeding is a new breeding method combining semi-dwarf breeding and heterosis breeding using germplasm and gene-environment interactions. This paper reviews the breeding strategies of super hybrid rice breeding in China, focusing on the utilization of heterosis of indica and japonica subspecies, construction of ideal plant architecture and pyramiding of disease resistant genes in restorer lines. To develop super hybrid rice, considerable effort should be made to explore genes related with high yield, good quality, resistance to pests and diseases, tolerance to stresses. Molecular breeding methods in combination with crossing techniques should be adopted in super hybrid rice breeding.

关键词： super hybrid rice     breeding strategies     yield potential    

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Study of mechanism of activating flux increasing weld penetration of AC A-TIG welding for aluminum alloy

HUANG Yong, FAN Ding, FAN Qinghua

《机械工程前沿（英文）》 2007年 第2卷 第4期   页码 442-447 doi: 10.1007/s11465-007-0076-9

摘要： When multi-component flux AF305 is used as surface activating flux for an aluminum alloy, the weld pene tration of activating flux-tungsten inert-gas (A-TIG) welding is over two times more than that of conventional TIG welding. Using A-TIG welding with the modes of alternating current (AC), direct current electrode negative (DCEN) and direct current electrode positive (DCEP), respectively, the flux differently affects weld penetration when the polarity is different. After studied the effect of compelled arc con striction on weld penetration of AC welding, it is believed that the constriction of the whole arc root is not the main mechanism that flux AF305 dramatically improves weld penetration. The penetration has a relationship with the separate distribution of slag on the weld surface. Then, an observation of scanning electron microscopy (SEM) and an electronic data systems (EDS) analysis of slag were performed respectively. The separate distribution of slag on the weld pool during welding and the great constriction of arc spots were confirmed by TIG welding with helium shielding gas. The relationship between slag distribution and weld penetration was studied by adding aluminum powder into flux AF305 to change the distribution of slag. During welding, the separate distribution of slag on the weld pool results in the great constriction of arc spots, an increase in arc spot force, and an increase in Lorentz force within the arc and weld pool. Finally, the weld penetration is increased.

关键词： A-TIG welding     surface     DCEN     electrode negative     increase    

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齿轮技术的创新和发展趋势

梁桂明

《中国工程科学》 2000年 第2卷 第3期   页码 1-6

摘要：

最早的齿轮是怎样发明出来的？它源于何方？用于何处？——这是近百年来人们在探索的一个谜。 两千年前，在中国、印度、希腊、罗马、埃及出土和出水的铸铁齿轮与青铜齿轮似乎解开了这个谜。其实不然， 它们只是第2代齿轮。第1代齿轮是木制齿轮。它源于四千年前，各文明古国发明水力机械中伴生。这是由于 这些文明古国聚居大河与海湾，与水有“缘分”所致。第2代齿轮的辉煌点表现在公元前200年中国的发明 ——指南车上。它在世界上第一次发明了差动机构，第一次实现半自动控制机构，第一次出现有走向功能的机 器人。1800年工业革命带来了第3代齿轮，其特征是用直刃刀具成批生产渐开线的钢制齿轮形成了现代齿轮的 技术平台。进人21世纪，以高强度复合材料代替资源匮乏的钢材，标志着新一代（第4代）齿轮的到来，它将 与知识经济共存。未来50年齿轮创新的趋势，是追求小化、净化、静化，高可靠性、高强度、高转速和低材 耗、低能耗、低重量。

关键词： 齿轮     创新     发展趋势    

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Increasing significance of advanced physical/chemical processes in the development and application of

RULKENS Wim

《环境科学与工程前沿（英文）》 2008年 第2卷 第4期   页码 385-396 doi: 10.1007/s11783-008-0073-1

摘要： The awareness of the problem of the scarcity of water of high quality has strongly changed the approach of wastewater treatment. Currently, there is an increasing need for the beneficial reuse of treated wastewater and to recover valuable products and energy from the wastewater. Because microbiological treatment methods are, only to a limited part, able to satisfy these needs, the role and significance of physical/chemical processes in wastewater treatment are gaining more and more interest. The specific future role and aim of the various physical/chemical treatment processes can be categorized in five groups: improvement of the performance of microbiological treatment processes, achievement of the high quality required for reuse of the effluent, recovery of valuable components and energy from the wastewater for beneficial reuse, desalination of brackish water and seawater, and treatment of concentrated liquid or solid waste residues produced in a wastewater treatment process. Development of more environmentally sustainable wastewater treatment chains in which physical/chemical processes play a crucial role, also requires application of process control and modeling strategies. This is briefly introduced by the elaboration of treatment scenarios for three specific wastewaters.

关键词： control     beneficial     valuable     scarcity     Development    

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Trend detection and stochastic simulation prediction of streamflow at Yingluoxia hydrological station

Chenglong ZHANG,Mo LI,Ping GUO

《农业科学与工程前沿（英文）》 2017年 第4卷 第1期   页码 81-96 doi: 10.15302/J-FASE-2016112

摘要： Investigating long-term variation and prediction of streamflow are critical to regional water resource management and planning. Under the continuous influence of climate change and human activity, the trends of hydrologic time series are nonstationary, and consequently the established methods for hydrological frequency analysis are no longer applicable. Five methods, including the linear regression, nonlinear regression, change point analysis, wavelet analysis and Hilbert-Huang transformation, were first selected to detect and identify the deterministic and stochastic components of streamflow. The results indicated there was a significant long-term increasing trend. To test the applicability of these five methods, a comprehensive weighted index was then used to assess their performance. This index showed that the linear regression was the best method. Secondly, using the normality test for stochastic components separated by the linear regression method, a normal distribution requirement was satisfied. Next, the Monte Carlo stochastic simulation technique was used to simulate these stochastic components with normal distribution, and thus a new ensemble hydrological time series was obtained by combining the corresponding deterministic components. Finally, according to these outcomes, the streamflow at different frequencies in 2020 was predicted.

关键词： Monte Carlo     nonstationary     trend detection     streamflow prediction     decomposition and ensemble     Yingluoxia    

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Temporal trend of mortality from major cancers in Xuanwei, China

null

《医学前沿（英文）》 2015年 第9卷 第4期   页码 487-495 doi: 10.1007/s11684-015-0413-z

摘要：

Although a number of studies have examined the etiology of lung cancer in Xuanwei County, China, other types of cancer in this county have not been reported systematically. This study aimed to investigate the temporal trend of eight major cancers in Xuanwei County using data from three mortality surveys (1973–1975, 1990–1992, and 2004–2005). The Chinese population in 1990 was used as a standard population to calculate age-standardized mortality rates. Cancers of lung, liver, breast, brain, esophagus, leukemia, rectum, and stomach were identified as the leading cancers in this county in terms of mortality rate. During the three time periods, lung cancer remained as the most common type of cancer. The mortality rates for all other types of cancer were lower than those of the national average, but an increasing trend was observed for all the cancers, particularly from 1990–1992 to 2004–2005. The temporal trend could be partly explained by changes in risk factors, but it also may be due to the improvement in cancer diagnosis and screening. Further epidemiological studies are warranted to systematically examine the underlying reasons for the temporal trend of the major cancers in Xuanwei County.

关键词： cancer     mortality     Xuanwei     temporal trend    

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Detection of critical road roughness sections by trend analysis and investigation of driver speed interaction

Meltem SAPLIOGLU; Ayse UNAL; Melek BOCEK

《结构与土木工程前沿（英文）》 2022年 第16卷 第4期   页码 515-532 doi: 10.1007/s11709-022-0814-4

摘要： Pavement roughness (IRI—International Roughness Index values) influence the stability of traffic movements both on intercity roads and urban roads. This study is to determine the exact locations of critical pavement roughness values that affect traffic motion stability and comfort in city centre highway arteries. Roughness data with 10 m intervals were collected on a 3140 m divided road containing three consecutive signalized intersections in the city centre arterial. These data were analysed using the distance-dependent Mann-Kendall trend analysis method and checkerboard model. The sections where roughness is important were determined at a 95% confidence interval. The results will show where future pavement improvements should be prioritized for municipalities and road maintenance engineers and will form a basis for the urban road management system.

关键词： trend analysis     checkerboard model     IRI     driver speed    

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Atomic and close-to-atomic scale manufacturing—A trend in manufacturing development

Fengzhou FANG

《机械工程前沿（英文）》 2016年 第11卷 第4期   页码 325-327 doi: 10.1007/s11465-016-0402-1

摘要：

Manufacturing is the foundation of a nation’s economy. It is the primary industry to promote economic and social development. To accelerate and upgrade China’s manufacturing sector from “precision manufacturing” to “high-performance and high-quality manufacturing”, a new breakthrough should be found in terms of achieving a “leap-frog development”. Unlike conventional manufacturing, the fundamental theory of “Manufacturing 3.0” is beyond the scope of conventional theory; rather, it is based on new principles and theories at the atomic and/or close-to-atomic scale. Obtaining a dominant role at the international level is a strategic move for China’s progress.

关键词： atomic manufacturing     Manufacturing 3.0     Manufacturing 2025     Industry 4.0    

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Innovation-driven trend shaping COVID-19 vaccine development in China

《医学前沿（英文）》 doi: 10.1007/s11684-023-1034-6

摘要： Confronted with the coronavirus disease 2019 (COVID-19) pandemic, China has become an asset in tackling the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission and mutation, with several innovative platforms, which provides various technical means in this persisting combat. Derived from collaborated researches, vaccines based on the spike protein of SARS-CoV-2 or inactivated whole virus are a cornerstone of the public health response to COVID-19. Herein, we outline representative vaccines in multiple routes, while the merits and plights of the existing vaccine strategies are also summarized. Likewise, new technologies may provide more potent or broader immunity and will contribute to fight against hypermutated SARS-CoV-2 variants. All in all, with the ultimate aim of delivering robust and durable protection that is resilient to emerging infectious disease, alongside the traditional routes, the discovery of innovative approach to developing effective vaccines based on virus properties remains our top priority.

关键词： SARS-CoV-2     COVID-19 vaccine     vaccine development    

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研发全球化是经济全球化的新趋势

张彦仲

《中国工程科学》 2005年 第7卷 第9期   页码 14-17

摘要：

分析了经济全球化对世界发展产生的重大影响，提出研发全球化是经济全球化的一个新阶段；研究了研发全球化的机遇与挑战及对经济全球化的促进和影响；分析了跨国公司在中国设立研发机构的特点；提出了鼓励在发展中国家建立研发机构的措施及发展中国家应采取的对策。

关键词： 研发全球化     经济全球化     跨国公司     研发中心     新趋势    

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The development trend and practical innovation of smart cities under the integration of new technologies

Xiaohong CHEN

《工程管理前沿（英文）》 2019年 第6卷 第4期   页码 485-502 doi: 10.1007/s42524-019-0057-9

摘要： Smart cities have rapidly developed in the context of the integration of new digital technologies such as big data, Internet of Things, artificial intelligence, blockchains, and virtual reality. These cities have conducted practical innovations and typical cases in many sectors, such as in government, transportation, environmental protection, energy, medical care, and logistics, and have produced many social, economic, and ecological benefits. However, there are still some problems that continue to hinder the construction of smart cities. This paper examines such problems in depth and proposes some relevant countermeasures and suggestions.

关键词： new technology integration     smart city     big data     practical innovation    

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U-shaped microRNA expression pattern could be a new concept biomarker for environmental estrogen

Rui Duan, Yun Lu, Lingyan Hou, Lina Du, Lequn Sun, Xingfan Tang

《环境科学与工程前沿（英文）》 2016年 第10卷 第6期 doi: 10.1007/s11783-016-0880-8

摘要： Estrogen regulates miRNA expression in a typical U-shaped dose-response pattern. E2 can regulate in the ventral prostate. Mouse ventral prostate is most sensitive to estrogen. Nonmonotonic dose-response in prostate could be a component of estrogen signature. Many studies have focused on environmental estrogen-related diseases. However, no consistent gene markers or signatures for estrogenicity have been discovered in mammals. This study investigated the estrogenic effects of 17β-estradiol on the prostate in immature male mice. Consistent U-shaped responses were seen in bodyweight, ventral prostate epithelial morphology, and miRNA expression levels. Specifically, most estradiol regulated miRNAs were downregulated at low doses of estradiol (0.2 and 2 mg·kg ), and whose expression returned to the control level at a larger dose (200 mg·kg ). The function of these regulated miRNAs is related to the prostate cancer and PI3K-Akt signaling pathways, which is consistent with the function of estradiol. Furthermore, the miRNA-processing machinery, Drosha, in the prostate was also regulated in a similar pattern, which could be a part of the U-shaped miRNA expression mechanism. All of these data indicate that the prostate is a reliable organ for evaluating estrogenic activity and that the typical nonmonotonic dose-response relationship could be used as a novel biomarker for estrogenicity.

关键词： miRNA     Prostate     Estradiol     Nonmonotonic dose-response     Estrogenicity     Drosha    

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标题 作者 时间 类型 操作

Numerical study on laminar flame speed of natural gas-carbon monoxide-air mixtures

Chen DONG, Qulan ZHOU, Qinxin ZHAO, Tongmo XU, Shi’en HUI

期刊论文

Study on reformulation of fluid catalytic cracking gasoline and increasing production of light olefins

YAN Pingxiang, MENG Xianghai, GAO Jinsen, XU Chunming, SUI Zhiyu

期刊论文

Influence of increasing numbers of RE-inverters on the power quality in the distribution grids: A PQ

Przemyslaw JANIK, Grzegorz KOSOBUDZKI, Harald SCHWARZ

期刊论文

Breeding strategies for increasing yield potential in super hybrid rice

Shihua CHENG,Xiaodeng ZHAN,Liyong CAO

期刊论文

Study of mechanism of activating flux increasing weld penetration of AC A-TIG welding for aluminum alloy

HUANG Yong, FAN Ding, FAN Qinghua

期刊论文

齿轮技术的创新和发展趋势

梁桂明

期刊论文

Increasing significance of advanced physical/chemical processes in the development and application of

RULKENS Wim

期刊论文

Trend detection and stochastic simulation prediction of streamflow at Yingluoxia hydrological station

Chenglong ZHANG,Mo LI,Ping GUO

期刊论文

Temporal trend of mortality from major cancers in Xuanwei, China

null

期刊论文

Detection of critical road roughness sections by trend analysis and investigation of driver speed interaction

Meltem SAPLIOGLU; Ayse UNAL; Melek BOCEK

期刊论文

Atomic and close-to-atomic scale manufacturing—A trend in manufacturing development

Fengzhou FANG

期刊论文

Innovation-driven trend shaping COVID-19 vaccine development in China

期刊论文

研发全球化是经济全球化的新趋势

张彦仲

期刊论文

The development trend and practical innovation of smart cities under the integration of new technologies

Xiaohong CHEN

期刊论文

U-shaped microRNA expression pattern could be a new concept biomarker for environmental estrogen

Rui Duan, Yun Lu, Lingyan Hou, Lina Du, Lequn Sun, Xingfan Tang

期刊论文