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The Impact of the Establishment of National High-tech Zones on Total Factor Productivity of Chinese Enterprises
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作者 Wang Mingyi Liu Xiaoyu 《China Economist》 2023年第3期68-93,共26页
The National High-tech Zone(NHTZs)is an important strategic platform for cultivating high-tech industries and realizing high-quality economic development in China.Based on the combined data from 2006 to 2014 of the in... The National High-tech Zone(NHTZs)is an important strategic platform for cultivating high-tech industries and realizing high-quality economic development in China.Based on the combined data from 2006 to 2014 of the industrial enterprise database,the customs database,and the China Development Zones Audit and Announcement Catalogue(abbreviated asthe Catalogue),this paper systematically investigates the influence of the construction of NHTZs on enterprise’s total factor productivity(TFP).Results show that NHTZs have a positive impact on the TFP of enterprises in the zone,and this conclusion is still valid after considering endogeneity problems.Furthermore,the above productivity effects of NHTZs are heterogeneous in terms of enterprise ownership,external environment and establishment time,and NHTZs have greater stimulation effects on enterprise productivity after comparing with other types of functional zones.An investigation of the specific mechanisms at play shows that NHTZs promote the TFP of enterprises in the zone through the release of preferential policies,strengthening the“technology spillover effects”of imported intermediate goods,enhancing enterprise’s innovation ability and attracting talent.In addition,based on the decomposition of industry productivity,this paper also investigates the impact of NHTZs on changes in industry productivity and finds that NHTZs promote the overall productivity of specific industries mainly by stimulating the productivity improvement of incumbent enterprises and expanding the market share of high-productivity enterprises.Moreover,the preferential policies of NHTZs do not significantly stimulate high-productivity enterprises to enter the zones,nor do they cause low-productivity enterprises to exit.This research is helpful in objectively evaluating the economic effects of the NHTZs in China and in providing a theoretical basis for its further adjustment. 展开更多
关键词 National high-tech zones(NHTZs) total factor productivity(TFP) DIFFERENCE-IN-DIFFERENCES changes in industry productivity
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Comprehensive Control Measures and Effect Evaluation of Groundwater Over-exploitation Areas in High-tech Zone,Jining in 2020
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作者 Shengqing LI Fei XIE 《Meteorological and Environmental Research》 CAS 2022年第3期82-85,共4页
Groundwater over-exploitation is a major problem in groundwater development, utilization and protection. At present, the area of shallow groundwater over-exploitation in the High-tech Zone is 76 km^(2). In this study,... Groundwater over-exploitation is a major problem in groundwater development, utilization and protection. At present, the area of shallow groundwater over-exploitation in the High-tech Zone is 76 km^(2). In this study, the system and mechanism construction, engineering measure construction, and control effect of national comprehensive control project of groundwater over-exploitation areas in the High-tech Zone in 2020 were evaluated, and the comprehensive control of groundwater over-exploitation in the High-tech Zone in the year was summarized to provide effective basis for the continuous implementation of comprehensive control of groundwater over-exploitation. At the same time, the water-saving and exploitation reduction effect and generalizability of different measures were studied to provide useful reference for other over-exploitation areas. 展开更多
关键词 GROUNDWATER Over-exploitation area Exploitation reduction effect high-tech zone Jining
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Evolution of Industrial Competitiveness Based on Evaluation of Urban Competitiveness of Dongguan City:A Case Study of Songshan Lake High-tech Zone
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作者 TANG Shiyu LU Bin HE Dongran 《Journal of Landscape Research》 2020年第3期57-64,共8页
Based on the theoretical system of urban competitiveness,the evaluation model of urban competitiveness from the perspective of competition and cooperation was established.According to the significance index and explan... Based on the theoretical system of urban competitiveness,the evaluation model of urban competitiveness from the perspective of competition and cooperation was established.According to the significance index and explanatory index,the urban competitiveness was divided into urban comprehensive competitiveness(UC),urban internal node competitiveness(NC)and external competitiveness of urban network(EC).The scores and rankings of UC,NC and EC in 2006,2010 and 2015 were obtained by conducting the comprehensive evaluation of the urban competitiveness of Dongguan City with integrated usage of the principal component analysis and Technique for Order Preference by Similarity to an Ideal Solution and the data of other 20 cities in Guangdong province,Hong Kong and Macao.The research showed that the competitiveness of Dongguan City has been greatly improved during the decade of 2006–2015,and the regional cities in Guangdong Province had significant differences,which are reflected in the two dimensions of urban internal node competitiveness(NC)and external competitiveness of urban network(EC).Based on this,this study further analyzed Dongguan’s urban competitiveness from two dimensions of NC and EC,and took Dongguan Songshan Lake High-tech Zone as an example to study how to promote Dongguan’s urban competitiveness from the industrial level. 展开更多
关键词 Dongguan Songshan Lake high-tech zone External competitiveness of urban network Improvement of comprehensive competitiveness
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Chengdu High-Tech Zone
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《China Today》 2001年第4期28-29,共2页
关键词 Chengdu high-tech zone
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A Study on Theoretical Model and Applied Evaluation of Land Use Performance of High-tech Zone in Urban Fringe: A Case Study in Haidian District, Beijing 被引量:3
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作者 Ban Maosheng Fang Chuanglin Liu Xiaoli 《Chinese Journal of Population,Resources and Environment》 北大核心 2008年第1期91-96,共6页
High-tech industrial zone is an important carrier for constructing innovative cities. It also plays an important role in implementing the national independent innovative strategy. How-ever, most of the high-tech indus... High-tech industrial zone is an important carrier for constructing innovative cities. It also plays an important role in implementing the national independent innovative strategy. How-ever, most of the high-tech industrial zones have many problems in their development process, such as efficiency of land use, weakness of oriented function and lack of land intensive. To solve these problems, the authors of this paper introduced the concept of land use performance and established the theoretical model to assess the land use performance of high-tech industrial zones. The model consists of the following three-dimensional parts: land use benefit, land use efficiency and innovative function. Based on this theory model, an index system which was composed of three secondary indictors, eight tertiary indictors and 37 fourth-grade indictors was set up to evaluate the land use performance of high-tech zone. To avoid the defects of plus model and function model, the authors brought out a three-dimensional evaluation model to examine the index of the land use performance of the high-tech industrial parks, which equals to the evaluation indicator system of land use performance of high-tech zone based on the above research. The authors examined the land use performance of five different high-tech industrial parks in Haidian District, Beijing City. The results indicated that the indicator system per-forms better in the aspect of evaluating land use benefit, land use efficiency and function of the high-tech industrial zone compared with other models. 展开更多
关键词 海淀区 北京 城乡结合部 高科技工业园区 土地利用 理论模型 创新能力
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The Role of China's High-Tech Zones in Its Regional Economic Development 被引量:2
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作者 刘瑞明 赵仁杰 《China Economist》 2016年第5期44-56,共13页
National high-tech industrial development zones represent a major strategy of the Chinese government in developing high-tech industries and spurring regional economic growth. The effect of this policy is yet to be pro... National high-tech industrial development zones represent a major strategy of the Chinese government in developing high-tech industries and spurring regional economic growth. The effect of this policy is yet to be proven. Based on the panel data of 283 Chinese cities between 1984 and 2012, this paper investigates the effect of high-tech zones on regional economic development. Empirical results suggest that first, national hightech zones have remarkably enhanced regional GDP and per capita GDP growth, and this conclusion still holds true after multiple rounds of robustness test; second, the economic effect of national high-tech zones is subject to diminishing marginal return and compared with higher-tier cities, lower-tier cities benefited more from the creation of national hightech zones. This paper concludes that national high-tech zones where special policies are experimented and offered not only drive economic development but, if properly distributed across regions, may help reduce regional economic disparities as well. The results of this study provide important implications for the future distribution of national high-tech zones and the creation of other relevant policies. 展开更多
关键词 区域经济发展 国家高新区 中国政府 高新技术产业开发区 中国城市 人均GDP 经济增长 生产总值
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Advances in seismological methods for characterizing fault zone structure
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作者 Yan Cai Jianping Wu +1 位作者 Yaning Liu Shijie Gao 《Earthquake Science》 2024年第2期122-138,共17页
Large earthquakes frequently occur along complex fault systems.Understanding seismic rupture and long-term fault evolution requires constraining the geometric and material properties of fault zone structures.We provid... Large earthquakes frequently occur along complex fault systems.Understanding seismic rupture and long-term fault evolution requires constraining the geometric and material properties of fault zone structures.We provide a comprehensive overview of recent advancements in seismological methods used to study fault zone structures,including seismic tomography,fault zone seismic wave analysis,and seismicity analysis.Observational conditions limit our current ability to fully characterize fault zones,for example,insufficient imaging resolution to discern small-scale anomalies,incomplete capture of crucial fault zone seismic waves,and limited precision in event location accuracy.Dense seismic arrays can overcome these limitations and enable more detailed investigations of fault zone structures.Moreover,we present new insights into the structure of the Anninghe-Xiaojiang fault zone in the southeastern margin of the Qinghai-Xizang Plateau based on data collected from a dense seismic array.We found that utilizing a dense seismic array can identify small-scale features within fault zones,aiding in the interpretation of fault zone geometry and material properties. 展开更多
关键词 fault zone structure TOMOGRAPHY fault zone wave seismic activity Anninghe-Xiaojiang fault zone
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Marginal zone lymphoma with severe rashes: A case report
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作者 Si-Jun Bai Ye Geng +7 位作者 Yi-Nan Gao Cai-Xia Zhang Qian Mi Chen Zhang Jia-Ling Yang Si-Jie He Zhen-YingYan Jian-Xia He 《World Journal of Clinical Cases》 SCIE 2024年第3期565-574,共10页
BACKGROUND Marginal zone lymphoma(MZL)is an indolent subtype of non-Hodgkin lymphoma(NHL),which is rare clinically with severe rashes as the initial symptom.CASE SUMMARY This study reports a case of MZL with generaliz... BACKGROUND Marginal zone lymphoma(MZL)is an indolent subtype of non-Hodgkin lymphoma(NHL),which is rare clinically with severe rashes as the initial symptom.CASE SUMMARY This study reports a case of MZL with generalized skin rashes accompanied by pruritus and purulent discharge.First-line treatment with rituximab combined with zanubrutinib had poor effects.However,after switching to obinutuzumab combined with zanubrutinib,the case was alleviated,and the rashes disappeared.CONCLUSION For patients with advanced stage MZL not benefiting from type I anti-CD20 monoclonal antibody(mAb)combination therapy,switching to a type II anti-CD20 mAb combination regimen may be considered.This approach may provide a new perspective in the treatment of MZL. 展开更多
关键词 Marginal zone lymphoma Mucosa-associated lymphoid tissue Extranodal marginal zone lymphoma Primary cutaneous marginal zone lymphoma Rituximab Obinutuzumab Zanubrutinib Case report
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Formation mechanism of fault accommodation zones under combined stress in graben basin:Implications from geomechanical modeling
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作者 Qi-Qiang Ren Jin-Liang Gao +3 位作者 Rong-Tao Jiang Jin Wang Meng-Ping Li Jian-Wei Feng 《Petroleum Science》 SCIE EI CAS CSCD 2024年第1期54-76,共23页
A fault accommodation zone is a type of structure that is defined as regulating displacement and strain between faults structure.Increasing numbers of fault accommodation zones are being identified in graben basins,in... A fault accommodation zone is a type of structure that is defined as regulating displacement and strain between faults structure.Increasing numbers of fault accommodation zones are being identified in graben basins,indicating the potential exploration target and petroleum accumulation areas.This study aims to analyze the formation mechanism and development of fault accommodation zones under combined stress by a numerical simulation method considering geomechanical modeling.Using three-dimensional(3-D)seismic interpretation and fractal dimension method,exampled with the Dongxin fault zone,the fault activity and fault combination pattern were conducted to quantitatively characterize the activity difference in fault accommodation zones.Combined with mechanical experiment test,a geomehcanical model was established for fault accommodation zones in a graben basin.Integrating the paleostress numerical simulations and structural physical simulation experiment,the developmental characteristics and genetic mechanism of fault accommodation zones were summarized.Influenced by multi movements and combined stresses,three significant tectonic evolution stages of the Dongxing Fault Zone(DXFZ)were distinguished:During the E_(s)^(3)sedimentary period,the large difference in the stress,strain,and rupture distribution in various faults were significant,and this stage was the key generation period for the prototype of the DXFZ,including the FAZ between large-scale faults.During the E_(s)^(2)sedimentary period,the EW-trending symmetric with opposite dipping normal faults and the NE-SW trending faults with large scale were furtherly developed.The junction area of two secondary normal faults were prone to be ruptured,performing significant period for inheriting and developing characteristics of fault accommodation zones.During the Es1 sedimentary period,the high-order faults in the DXFZ exhibited the obvious fault depressions and strike-slip activity,and the fault accommodation zones were furtherly inherited and developed.This stage was the molded and formative period of the FAZ,the low-order faults,and the depression in the DXFZ. 展开更多
关键词 Fault accommodation zone Graben basin Fault activity Tectonic physical simulation experiment Finite element numerical simulation Dongxin fault zone
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Performance analysis of single-focus phase singularity based on elliptical reflective annulus quadrangle-element coded spiral zone plates
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作者 臧华平 王宝珍 +7 位作者 郑程龙 魏来 范全平 王少义 杨祖华 周维民 曹磊峰 郭海中 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第1期441-448,共8页
Optical vortices generated by the conventional vortex lens are usually disturbed by the undesired higher-order foci,which may lead to additional artifacts and thus degrade the contrast sensitivity. In this work, we pr... Optical vortices generated by the conventional vortex lens are usually disturbed by the undesired higher-order foci,which may lead to additional artifacts and thus degrade the contrast sensitivity. In this work, we propose an efficient methodology to combine the merit of elliptical reflective zone plates(ERZPs) and the advantage of spiral zone plates(SZPs) in establishing a specific single optical element, termed elliptical reflective annulus quadrangle-element coded spiral zone plates(ERAQSZPs) to generate single-focus phase singularity. Differing from the abrupt reflectance of the ERZPs, a series of randomly distributed nanometer apertures are adopted to realize the sinusoidal reflectance. Typically, according to our physical design, the ERAQSZPs are fabricated on a bulk substrate;therefore, the new idea can significantly reduce the difficulty in the fabrication process. Based on the Kirchhoff diffraction theory and convolution theorem, the focusing performance of ERAQSZPs is calculated. The results reveal that apart from the capability of generating optical vortices,ERAQSZPs can also integrate the function of focusing, energy selection, higher-order foci elimination, as well as high spectral resolution together. In addition, the focusing properties can be further improved by appropriately adjusting the parameters, such as zone number and the size of the consisted primitives. These findings are expected to direct a new direction toward improving the performance of optical capture, x-ray fluorescence spectra, and forbidden transition. 展开更多
关键词 optical vortex single-focus spiral zone plate topological charges
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Bendamustine and rituximab as frontline therapy in extranodal marginal zone lymphoma:a single-institution experience
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作者 CONSTANTINE N.LOGOTHETIS NATHAN P.HORVAT +8 位作者 TONY KURIAN CELESTE BELLO JULIO CHAVEZ LEIDY ISENALUMHE BIJAL SHAH LUBOMIR SOKOL HAYDER SAEED JAVIER PINILLA SAMEH GABALLA 《Oncology Research》 SCIE 2024年第6期1031-1036,共6页
Extranodal marginal zone lymphoma(EMZL)encompasses 70%of cases of marginal zone lymphoma.Frontline bendamustine and rituximab(BR)were derived from trials involving other indolent non-Hodgkin’s lymphomas.Only one tria... Extranodal marginal zone lymphoma(EMZL)encompasses 70%of cases of marginal zone lymphoma.Frontline bendamustine and rituximab(BR)were derived from trials involving other indolent non-Hodgkin’s lymphomas.Only one trial has evaluated frontline BR prospectively in EMZL.This retrospective study reports outcomes among EMZL patients receiving frontline BR.Twenty-five patients were included with a median age of 69 years(40–81).Five(20.0%)patients had stage Ⅰ/Ⅱ disease,and 20(80.0%)had stage Ⅲ/Ⅳ disease.The median number of cycles was 6.0(3.0–6.0).Maintenance rituximab was administered to 10(41.7%)individuals.Overall response rate(ORR)was 100.0%(60.0%complete response,40.0%partial response).Medians of overall survival and progression-free survival were not reached.The estimated 2-year progression-free survival was 85.2%and overall survival was 100.0%.Four(16.6%)patients had infections related to treatment;3(12.0%)transformed to diffuse large B-cell lymphoma;5(20.8%)had a relapse or progression of EMZL;and 3(12.0%)died unrelated to BR.BR is an efficacious and well-tolerated front-line regimen for EMZL with response data consistent with existing literature. 展开更多
关键词 Extranodal marginal zone lymphoma BENDAMUSTINE RITUXIMAB Front-line therapy
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High-Efficiency Dynamic Scanning Strategy for Powder Bed Fusion by Controlling Temperature Field of the Heat-Affected Zone
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作者 Xiaokang Huang Xiaoyong Tian +5 位作者 Qi Zhong Shunwen He Cunbao Huo Yi Cao Zhiqiang Tong Dichen Li 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2024年第1期203-214,共12页
Improvement of fabrication efficiency and part performance was the main challenge for the large-scale powder bed fusion(PBF)process.In this study,a dynamic monitoring and feedback system of powder bed temperature fiel... Improvement of fabrication efficiency and part performance was the main challenge for the large-scale powder bed fusion(PBF)process.In this study,a dynamic monitoring and feedback system of powder bed temperature field using an infrared thermal imager has been established and integrated into a four-laser PBF equipment with a working area of 2000 mm×2000 mm.The heat-affected zone(HAZ)temperature field has been controlled by adjusting the scanning speed dynamically.Simultaneously,the relationship among spot size,HAZ temperature,and part performance has been established.The fluctuation of the HAZ temperature in four-laser scanning areas was decreased from 30.85℃to 17.41℃.Thus,the consistency of the sintering performance of the produced large component has been improved.Based on the controllable temperature field,a dynamically adjusting strategy for laser spot size was proposed,by which the fabrication efficiency was improved up to 65.38%.The current research results were of great significance to the further industrial applications of large-scale PBF equipment. 展开更多
关键词 Powder bed fusion EFFICIENCY LARGE-SCALE Spot size Heat-affected zone(HAZ)
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Early Triassic Volcanic Rocks in the Western Yarlung Zangbo Suture Zone:Implications for the Opening of the Neo-Tethys Ocean
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作者 HE Juan LI Yalin +4 位作者 HOU Yunling ZHOU Aorigele WEI Yushuai CHEN Xi DAI Jingen 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2024年第2期324-336,共13页
In this study,zircon U-Pb dating of volcanic rocks from the Zhongba ophiolite of the Yarlung Zangbo Suture Zone(YZSZ)in southern Xizang(Tibet)yielded an age of 247±3 Ma.According to whole rock geochemical and Sr-... In this study,zircon U-Pb dating of volcanic rocks from the Zhongba ophiolite of the Yarlung Zangbo Suture Zone(YZSZ)in southern Xizang(Tibet)yielded an age of 247±3 Ma.According to whole rock geochemical and Sr-NdPb isotopic data,the Early Triassic samples could be divided into two groups:Group 1 with P-MORB affinity,showing initial^(87)Sr/^(86)Sr ratios of 0.70253–0.70602,ε_(Nd)(t)values of 4.2–5.3,(^(206)Pb/^(204)Pb)_(t)ratios of 16.353–18.222,(^(207)Pb/^(204)Pb)_(t)ratios of 15.454–15.564,and(^(208)Pb/^(204)Pb)_(t)ratios of 35.665–38.136;Group 2 with OIB affinity,showing initial^(87)Sr/^(86)Sr ratios of 0.70249–0.70513,ε_(Nd)(t)values of 4.4–4.9,(^(206)Pb/^(204)Pb)_(t)ratios of 17.140–18.328,(^(207)Pb/^(204)Pb)_(t)ratios of 15.491–15.575,and(^(208)Pb/^(204)Pb)_(t)ratios of 36.051–38.247.Group 2 rocks formed by partial melting of the mantle source enriched by a former plume,and assimilated continental crustal material during melt ascension.The formation of Group 1 rocks corresponds to the mixing of OIB melts,with the same components as Group 2 and N-MORBs.The Zhongba Early Triassic rocks belong to the continental margin type ophiolite and formed in the continental–oceanic transition zone during the initial opening of the Neo-Tethys in southern Xizang(Tibet). 展开更多
关键词 RIFT Early Triassic magmatism Yarlung Zangbo Suture zone NEO-TETHYS Southern Xizang Tibet
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Improving creep strength of the fine-grained heat-affected zone of novel 9Cr martensitic heat-resistant steel via modified thermo-mechanical treatment
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作者 Jingwen Zhang Liming Yu +6 位作者 Yongchang Liu Ran Ding Chenxi Liu Zongqing Ma Huijun Li Qiuzhi Gao Hui Wang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第5期1037-1047,共11页
The infamous type Ⅳ failure within the fine-grained heat-affected zone (FGHAZ) in G115 steel weldments seriously threatens the safe operation of ultra-supercritical (USC) power plants.In this work,the traditional the... The infamous type Ⅳ failure within the fine-grained heat-affected zone (FGHAZ) in G115 steel weldments seriously threatens the safe operation of ultra-supercritical (USC) power plants.In this work,the traditional thermo-mechanical treatment was modified via the replacement of hot-rolling with cold rolling,i.e.,normalizing,cold rolling,and tempering (NCT),which was developed to improve the creep strength of the FGHAZ in G115 steel weldments.The NCT treatment effectively promoted the dissolution of preformed M_(23)C_(6)particles and relieved the boundary segregation of C and Cr during welding thermal cycling,which accelerated the dispersed reprecipitation of M_(23)C_(6) particles within the fresh reaustenitized grains during post-weld heat treatment.In addition,the precipitation of Cu-rich phases and MX particles was promoted evidently due to the deformation-induced dislocations.As a result,the interacting actions between precipitates,dislocations,and boundaries during creep were reinforced considerably.Following this strategy,the creep rupture life of the FGHAZ in G115 steel weldments can be prolonged by 18.6%,which can further push the application of G115 steel in USC power plants. 展开更多
关键词 G115 steel fine-grained heat-affected zone creep strength element segregation nano-sized precipitates
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Near-surface wind field characteristics of the desert-oasis transition zone in Dunhuang,China
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作者 PAN Jiapeng ZHANG Kecun +1 位作者 AN Zhishan ZHANG Yu 《Journal of Arid Land》 SCIE CSCD 2024年第5期654-667,共14页
The desert-oasis transition zone(DOTZ)serves as a buffer area between the desert and oasis.Understanding its wind field characteristics is of great significance for the prevention and control of aeolian disasters in t... The desert-oasis transition zone(DOTZ)serves as a buffer area between the desert and oasis.Understanding its wind field characteristics is of great significance for the prevention and control of aeolian disasters in the oasis.In this study,we used meteorological data during 2013–2019 from the portable meteorological stations at five sites(site A on the edge of the oasis,sites B,C,and D in the DOTZ,and site O in the desert)in Dunhuang,China to analyze the near-surface wind field characteristics and their causes,as well as to reveal the key role of the DOTZ in oasis protection.The results showed that the mean wind speed,frequency of sand-driving wind,and directional variability of wind decreased from west to east within the DOTZ,and wind speed was significantly affected by air temperature.The terrain influenced the prevailing winds in the region,mainly from northeast and southwest.Only some areas adjacent to the oasis were controlled by southeasterly wind.This indicated that the near-surface wind field characteristics of the DOTZ were caused by the combined effects of local terrain and surface hydrothermal difference.At site D,the annual drift potential(DP)was 24.95 vector units(VU),indicating a low wind energy environment,and the resultant drift direction(RDD)showed obvious seasonal differences.Additionally,the DOTZ played an important buffering role between the desert and oasis.Compared with the desert,the mean wind speed in the oasis decreased by 64.98%,and the prevailing wind direction was more concentrated.The results of this study will be useful in interpreting the aeolian activity of the DOTZ in Dunhuang. 展开更多
关键词 desert-oasis transition zone near-surface wind field hydrothermal difference sand-driving wind aeolian environment Dunhuang
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Vibration Control of A Flexible Marine Riser System Subject to Input Dead Zone and Extraneous Disturbances
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作者 ZHOU Li WANG Guo-rong WAN Min 《China Ocean Engineering》 SCIE EI CSCD 2024年第2期271-284,共14页
An observer-based adaptive backstepping boundary control is proposed for vibration control of flexible offshore riser systems with unknown nonlinear input dead zone and uncertain environmental disturbances.The control... An observer-based adaptive backstepping boundary control is proposed for vibration control of flexible offshore riser systems with unknown nonlinear input dead zone and uncertain environmental disturbances.The control algorithm can update the control law online through real-time data to make the controller adapt to the environment and improve the control precision.Specifically,based on the adaptive backstepping framework,virtual control laws and Lyapunov functions are designed for each subsystem.Three direction interference observers are designed to track the timevarying boundary disturbance.On this basis,the inverse of the dead zone and linear state transformation are used to compensate for the original system and eliminate the adverse effects of the dead zone.In addition,the stability of the closed-loop system is proven by Lyapunov stability theory.All the system states are bounded,and the vibration offset of the riser converges to a small area of the initial position.Finally,four examples of flexible marine risers are simulated in MATLAB to verify the effectiveness of the proposed controller. 展开更多
关键词 adaptive backstepping control disturbance observer flexible marine riser input dead zone vibration control
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Numerical investigation of geostress influence on the grouting reinforcement effectiveness of tunnel surrounding rock mass in fault fracture zones
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作者 Xiangyu Xu Zhijun Wu +3 位作者 Lei Weng Zhaofei Chu Quansheng Liu Yuan Zhou 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第1期81-101,共21页
Grouting is a widely used approach to reinforce broken surrounding rock mass during the construction of underground tunnels in fault fracture zones,and its reinforcement effectiveness is highly affected by geostress.I... Grouting is a widely used approach to reinforce broken surrounding rock mass during the construction of underground tunnels in fault fracture zones,and its reinforcement effectiveness is highly affected by geostress.In this study,a numerical manifold method(NMM)based simulator has been developed to examine the impact of geostress conditions on grouting reinforcement during tunnel excavation.To develop this simulator,a detection technique for identifying slurry migration channels and an improved fluid-solid coupling(FeS)framework,which considers the influence of fracture properties and geostress states,is developed and incorporated into a zero-thickness cohesive element(ZE)based NMM(Co-NMM)for simulating tunnel excavation.Additionally,to simulate coagulation of injected slurry,a bonding repair algorithm is further proposed based on the ZE model.To verify the accuracy of the proposed simulator,a series of simulations about slurry migration in single fractures and fracture networks are numerically reproduced,and the results align well with analytical and laboratory test results.Furthermore,these numerical results show that neglecting the influence of geostress condition can lead to a serious over-estimation of slurry migration range and reinforcement effectiveness.After validations,a series of simulations about tunnel grouting reinforcement and tunnel excavation in fault fracture zones with varying fracture densities under different geostress conditions are conducted.Based on these simula-tions,the influence of geostress conditions and the optimization of grouting schemes are discussed. 展开更多
关键词 Numerical manifold method(NMM) Grouting reinforcement Geostress condition Fault fracture zone Tunnel excavation
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Influence of ecological function protection zone on the water conservation in Gansu-Qinghai Contiguous Region of the upper Yellow River
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作者 TONG Huali CHEN Qingbo ZHANG Xuan 《Journal of Mountain Science》 SCIE CSCD 2024年第4期1345-1357,共13页
The implementation of Ecological Function Protection Zone(EFPZ)policy is significant for the ecological restoration and conservation of soil and water in the territory space.This manuscript analyzed and quantified the... The implementation of Ecological Function Protection Zone(EFPZ)policy is significant for the ecological restoration and conservation of soil and water in the territory space.This manuscript analyzed and quantified the impact of EFPZ on the regional water conservation function,based on land use data from 2005,2008,2010,2015 and 2020,by conducting a counterfactual simulation along with the GeoSOS-FLUS model and the InVEST model.The results demonstrate that the delineation of EFPZ can significantly influence the water conservation.(1)From 2010 to 2020,as the EFPZ was implemented,the water conservation in the study area was increasing year by year,with a growth rate of 0.03×10^(8) m^(3)∙a^(-1).On the other hand,the simulated water conservation capacity without the implementation of EFPZ decreased year by year,with a decrease rate of 0.01×10^(8) m^(3)∙a^(-1).(2)The EFPZ accounts for only 23%of the total area,but the contribution rate of water conservation reaches 80%.The actual values of water conservation and average water yield per unit pixel in the EFPZ show an increasing trend both internally and externally,while the counterfactual simulation values exhibit a decreasing trend.(3)The water conservation is much higher within the EFPZ than without EFPZ.The implementation of EFPZ has a significant effect on the improvement of the water conservation capacity in Maqu EFPZ and Yellow River Source EFPZ.The protection effectiveness should be enhanced in Qilian Mountain EFPZ and afforestation activities need to be carefully considered in Loess Plateau EFPZ. 展开更多
关键词 Water conservation function Ecological Function Protection zone Counterfactual simulation Geo SOS-FLUS model InVEST model
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One-year results for myopia control of orthokeratology with different back optic zone diameters: a randomized trial using a novel multispectral-based topographer
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作者 Wen-Ting Tang Xiang-Ning Luo +4 位作者 Wen-Jing Zhao Jia Liao Xin-Yue Xu Hui-Dan Zhang Li Zhang 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2024年第2期324-330,共7页
AIM:To present the 1-year results of a prospective cohort study investigating the efficacy,potential mechanism,and safety of orthokeratology(ortho-k)with different back optic zone diameters(BOZD)for myopia control in ... AIM:To present the 1-year results of a prospective cohort study investigating the efficacy,potential mechanism,and safety of orthokeratology(ortho-k)with different back optic zone diameters(BOZD)for myopia control in children.METHODS:This randomized clinical study was performed between Dec.2020 and Dec.2021.Participants were randomly assigned to three groups wearing ortho-k:5 mm BOZD(5-MM group),5.5 mm BOZD(5.5-MM group),and 6 mm BOZD(6-MM group).The 1-year data were recorded,including axial length,relative peripheral refraction(RPR,measured by multispectral refractive topography,MRT),and visual quality.The contrast sensitivity(CS)was evaluated by CSV-1000 instrument with spatial frequencies of 3,6,12,and 18 cycles/degree(c/d);the corneal higher-order aberrations(HOAs)were measured by iTrace aberration analyzer.The one-way ANOVA was performed to assess the differences between the three groups.The correlation between the change in AL and RPR was calculated by Pearson’s correlation coefficient.RESULTS:The 1-year results of 20,21,and 21 subjects in the 5-MM,5.5-MM,and 6-MM groups,respectively,were presented.There were no statistical differences in baseline age,sex,or ocular parameters between the three groups(all P>0.05).At the 1-year visit,the 5-MM group had lower axial elongation than the 6-MM group(0.07±0.09 vs 0.18±0.11 mm,P=0.001).The 5-MM group had more myopic total RPR(TRPR,P=0.014),with RPR in the 15°–30°(RPR 15–30,P=0.015),30°–45°(RPR 30–45,P=0.011),temporal(RPR-T,P=0.008),and nasal area(RPR-N,P<0.001)than the 6-MM group.RPR 15–30 in the 5.5-MM group was more myopic than that in the 6-MM group(P=0.002),and RPR-N in the 5-MM group was more myopic than that in the 5.5-MM group(P<0.001).There were positive correlations between the axial elongation and the change in TRPR(r=0.756,P<0.001),RPR 15–30(r=0.364,P=0.004),RPR 30–45(r=0.306,P=0.016),and RPR-N(r=0.253,P=0.047).The CS decreased at 3 c/d(P<0.001),and the corneal HOAs increased in the 5-MM group(P=0.030).CONCLUSION:Ortho-k with 5 mm BOZD can control myopia progression more effectively.The mechanism may be associated with greater myopic shifts in RPR. 展开更多
关键词 relative peripheral refraction ORTHOKERATOLOGY MYOPIA back optic zone diameter axial length multispectral refractive topography
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Evaluation of excavation damaged zones(EDZs)in Horonobe Underground Research Laboratory(URL)
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作者 Koji Hata Sumio Niunoya +1 位作者 Kazuhei Aoyagi Nobukatsu Miyara 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第2期365-378,共14页
Excavation of underground caverns,such as mountain tunnels and energy-storage caverns,may cause the damages to the surrounding rock as a result of the stress redistribution.In this influenced zone,new cracks and disco... Excavation of underground caverns,such as mountain tunnels and energy-storage caverns,may cause the damages to the surrounding rock as a result of the stress redistribution.In this influenced zone,new cracks and discontinuities are created or propagate in the rock mass.Therefore,it is effective to measure and evaluate the acoustic emission(AE)events generated by the rocks,which is a small elastic vibration,and permeability change.The authors have developed a long-term measurement device that incorporates an optical AE(O-AE)sensor,an optical pore pressure sensor,and an optical temperature sensor in a single multi-optical measurement probe(MOP).Japan Atomic Energy Agency has been conducting R&D activities to enhance the reliability of high-level radioactive waste(HLW)deep geological disposal technology.In a high-level radioactive disposal project,one of the challenges is the development of methods for long-term monitoring of rock mass behavior.Therefore,in January 2014,the long-term measurements of the hydro-mechanical behavior of the rock mass were launched using the developed MOP in the vicinity of 350 m below the surface at the Horonobe Underground Research Center.The measurement results show that AEs occur frequently up to 1.5 m from the wall during excavation.In addition,hydraulic conductivity increased by 2e4 orders of magnitude.Elastoplastic analysis revealed that the hydraulic behavior of the rock mass affected the pore pressure fluctuations and caused micro-fractures.Based on this,a conceptual model is developed to represent the excavation damaged zone(EDZ),which contributes to the safe geological disposal of radioactive waste. 展开更多
关键词 Excavation damaged zone(EDZ) Optical sensor Long-term monitoring Acoustic emission(AE) Shaft sinking
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