Table of Content

20 November 2020, Volume 56 Issue 6

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Preparation and Pyrolysis Kinetics of Phenolic Resins of Main Phenols in Semi-coking Wastewater

WANG Yali, WANG Yufei, LI Jian, PENG Jiajia, CAO Shuai, YAN Long

2020, 56(6):  975-982.  DOI: 10.13209/j.0479-8023.2020.030

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The composition and concentration of organic compounds in semi-coking wastewater were determined by GC-MS. The mixtures of a few of the five most representative phenolic substances (phenol, m-cresol, 2,3-dimethylphenol, catechol and 2,6-dimethylphenol) were utilized to simulate semi-coking wastewater. Phenolic resins in the simulated semi-coking wastewater were prepared in the presence of formaldehyde. The phenolic resins were characterized by in-situ infrared and thermal analysis. The pyrolysis kinetic parameters obtained from analyzing thermogravimetric analysis data indicated that a mixture of phenolic compounds had higher crosslinking degree and the phenolic resin was more stable. This study provides a theoretical basis for optimizing of semicoking wastewater treatment by utilizing formaldehyde.

Butterfly Diversity in Tangjiahe National Nature Reserve, Sichuan Province

FAN Cheng, XIAO Mei, LEI Ying, LI Jialian, WEI Jun, YANG Jianing, ZHANG Dan, ZHOU Tingting, HU Ping, CHEN Limin, WANG Rongjiang

2020, 56(6):  983-995.  DOI: 10.13209/j.0479-8023.2020.074

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A systematic survey was conducted in Tangjiahe National Nature Reserve (TNNR) in Sichuan Province from mid-April to late October, 2014 (13 repeats altogether, about 15 days between repeats). 244 butterfly species were found in total belonging to 12 families and 116 genera, in which the richness of Nymphalidae was the highest (40.2%). There were 4 species protected by Chinese law, and 2 species assessed globally as “least concern” by IUCN Red List. The proportion of Palearctic, Oriental, and Palearctic-Oriental species was 3.3%, 26.7%, and 70%, respectively. There were more butterfly species from June to September. Butterfly species richness increased with elevation rising in 1100–1400 m, and decreased significantly above 1400 m. There were 185 species in common between Tangjiahe Nature Reserve and Laohegou Nature Reserve (LNR), in the context of their adjacency. There were 59 species found exclusively in TNNR, including 30 species with only 1 catching record. There were 67 species found exclusively in LNR, including 36 species with 1 catching record. Difference in geography and management between the two areas may provide specific habitat for the endemic species.

Multi-subband Ensemble Monte Carlo Simulation of InGaAs Schottky Barrier MOSFETs

LI Jinpei, DU Gang, LIU Lifeng, LIU Xiaoyan

2020, 56(6):  996-1004.  DOI: 10.13209/j.0479-8023.2020.106

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With the help of a multi-subband, multi-valley ensemble Monte Carlo simulator, which takes into account of multiple scattering mechanisms present in nano-scale MOSFET channel’s two-dimensional electron gas, InGaAs Schottky barrier MOSFET is simulated. The results show that under steady state, although scattering alters its carrier density, velocity and electric potential distribution, Schottky barrier MOSFET’s output and transfer characteristic is merely impacted by scattering. When a step voltage is applied to the device’s drain contact, scattering increases the device’s peak over-shoot current and transition time. Besides, scattering also reduces the cut-off frequency, especially for short channel device.

An Interference Fair Queueing I/O Scheduler under High Performance Processors

SUI Yan, YE Jiacheng, YANG Chun, TONG Dong

2020, 56(6):  1005-1012.  DOI: 10.13209/j.0479-8023.2020.100

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High performance processors and systems require high storage bandwidth and efficient external I/O processing. Many systems using high performance processors server a mixture of fully backlogged users, which continuously demand resources, and non-fully backlogged users. This presents challenges for fair resource management in multi-programmed computer systems and multi-tenant super computer systems. This paper develops a new storage I/O scheduler IFQ (interference fair queueing) for parallel accessible devices, such as SSDs. IFQ is implemented in Linux and compared with several existing I/O schedulers—Linux CFQ, STF, MFAP scheduler and MFAP scheduler with short time-slices. Results on synthetic I/O benchmarks, trace benchmarks, and real-world benchmarks demonstrate that only IFQ can achieve both fairness and high responsiveness.

A BFGS-Corrected Gauss-Newton Solver for Bundle Adjustment

ZHAO Shuaihua, LI Yanyan, CAO Jian, CAO Xixin

2020, 56(6):  1013-1019.  DOI: 10.13209/j.0479-8023.2020.098

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Aiming at the problem that the Gauss-Newton (GN) method is sensitive to the initial information matrix in the Bundle Adjustment (BA) model, which leads to limited application scenarios, the paper proposes a novel method BFGS-GN using BFGS (Broyden-Fletcher-Goldfarb-Shanno) algorithm to improve the traditional Gauss-Newton method. When the information matrix of the Gauss-Newton method loses positive definiteness, BFGS algorithm can be used to modify the normal equations, which fundamentally eliminates the mathematical defect that the Gauss-Newton method is sensitive to initial values. Experimental results demonstrate that proposed method is robust to different types of initials. The same accuracy and the number of iterations as GN can be obtained when the initial values are good. As for bad inputs, GN-based BA method cannot work but BFGS-GN can converge to a minimum.

Research on Sharing Access and Performance Improvement Based on User-Space File System

YANG Hongzhang, YANG Yahui, SUN Guangyu

2020, 56(6):  1020-1030.  DOI: 10.13209/j.0479-8023.2020.107

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This paper designs UHSFS, a user-space high-performance shared file system for NVMe SSD, proposing simple elastic data layout technology, elastic separation of multiple IO queues technology, and multiuser shared memory architecture. The metadata operation performance and IO processing ability are significantly improved, and the shared access of user-space file system is realized. Experiments show that UHSFS has the best metadata operation performance and Filebench workload performance, compared with user-space file systems including UNFS, NVFUSE, BLOBFS, and BLUEFS; queue separation technology can greatly improve IOPS and throughput; UHSFS also has better performance compared with kernel-space file systems including F2FS, XFS and Ext4.

Design of Bessel Beam Optical Tweezers for Single Particle Study

ZHAO Weilun, CAI Chen, ZHAO Gang, ZHAO Chunsheng

2020, 56(6):  1031-1037.  DOI: 10.13209/j.0479-8023.2020.090

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Bessel beam optical tweezer is built for particle measurement. An axicon is used to generate Bessel beam. The trapped single aerosol particle is stably levitated by optical force exerted by Bessel beam and drag force exerted by the counter gas flow. In combination with light signal scattered by the levitated aerosol particle, the diameter and the refractive index can be measured. Physicochemical properties of aerosol, such as hygroscopicity, volatility, and the refractive index, could be studied under different environmental conditions with this system.

Study on the Impact of Frequent Replacement of Commercial Stores along the Street on the Ecological Environment

HAN Xili, WANG Longhong

2020, 56(6):  1038-1046.  DOI: 10.13209/j.0479-8023.2020.094

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This paper takes the modern commercial street in Nanshan District of Shenzhen City, Xili commercial street and Pingshan commercial street in the city village as the research objects. According to the calculation and comparison of the total life cycle of buildings, the construction waste and carbon emissions generated in the process of shop replacement along the street are compared. From the perspective of architectural adaptability design, the following conclusions are drawn. In the process of shop replacement along the street, the differences between shop floor area and store replacement type are the main factors affecting carbon emissions. Smaller shops are conducive to the same type of shop replacement , so as to reduce the amount of construction waste generated by demolition and decoration , and then reduce the amount of construction carbon emissions to protect the ecological environment. The conclusion of this study gives some guidance to the renovation, planning, design and management of stores along the street.

Urgency Classification of Beijing Ecological Security Pattern Protection

YU Chaoyue, WANG Chenxu, FENG Zhe, WU Kening, ZHAO Huafu

2020, 56(6):  1047-1055.  DOI: 10.13209/j.0479-8023.2020.093

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Taking Beijing as an example, the granularity back-calculation method and the landscape connectivity index were combined to identify important ecological land. The neighborhood analysis was adopted to construct the ecological resistance surface, whereas the minimum cumulative resistance model was used to construct the ecological security pattern. The probability of land expansion calculated through an artificial neural network was used to classify the ecological security pattern of construction. The results show that the important ecological land area of Beijing is 6488.53 km², mainly distributed in the mountainous areas of western and northeastern Beijing, and a small part is located in the southeast plain area. The primary protection ecological land area is 4482.48 km², mainly distributed in the northwest and southwest. The secondary protection ecological land area is 1338.27 km², which is mainly distributed in the western suburbs, the suburban plains in the southwest and the plains in the southeast. The third-level protection ecological land area is 669.77 km², mainly distributed in the north-central and southeast plains. The important ecological corridor is 2410.47 km long and is distributed in the outer suburbs and urban-rural junction. Among them, the length of the first-class ecological corridor is 1477.63 km, mainly distributed in the mountainous areas of the northwest and southwestern suburbs; the secondary ecological corridor is 390.91 km, which is mainly distributed near the ecological land of the outer suburb plain; the third-level ecological corridor is 541.93 km, mainly distributed in the surrounding area of the city center, surrounded by the central city.

Evaluation and Promotion Countermeasures of Bird Carrying Capacity of Mangrove Wetland in Guangdong-Hong Kong-Macau Greater Bay Area: A Case Study of Futian Mangrove, Shenzhen Bay

WU Hailun, ZHOU Lin, XU Hualin, SHEN Xiaoxue, CHAI Minwei, LI Ruili

2020, 56(6):  1056-1064.  DOI: 10.13209/j.0479-8023.2020.066

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Focus on bird carrying capacity assessment in wetland ecological health assessment, the conversion method of ash free dry weight (AFDW) data of benthos was established, and the classification standard was optimized based on bird length. Taking Futian mangrove wetland as an example, the total food mass of benthos, the maximum calories for shorebirds and the field metabolic rate of shorebirds population were calculated. Furthermore, the carrying capacity of shorebirds was evaluated. The results are as follows. 1) The total food mass of benthos in Futian mangrove wetland had evident seasonal characteristics: winter (4.67×10⁴ kg) < spring (6.08×10⁴ kg)4 kg)5 kg). In autumn, the food mass density (in AFDW) of different

habitats was as follows: mangrove area (89.22 g/m²) > beach area (3.58 g/m²) > gei wei fish pond area (0.22 g/m²). 2) The maximum calories for shorebirds in different seasons were winter (1.03×10⁸ kJ) < spring (1.36×10⁸ kJ) < summer (1.76×10⁸ kJ) < autumn (2.70×10⁸ kJ). 3) The field metabolic rate of the shorebirds population in Futian mangrove wetland was 467.27 kJ/d. 4) Autumn, winter and spring were the migration periods for migratory birds, and the carrying capacity of Futian mangrove wetland to shorebirds was 6431, 2438 and 3235 birds respectively. The actual observation data was higher than the research results, indicating that the current carrying capacity of shorebirds in the Futian mangrove wetland was insufficient to meet the food needs of birds in migration season, and the number of shorebirds might be reduced. It is suggested that the ecological protection of mangrove wetland in Futian should be strengthened in the following three aspects: the restoration and reconstruction of mangrove

vegetation, the ecological restoration and functional improvement of gei wei fish pond, and the dynamic monitoring of birds and benthos. In this way, the total food mass of benthos and the bird carrying capacity can be lifted.

Effect of Glacial Buzzsaw during Quaternary in Puland, Tibet

GUO Hao, LIU Gengnian

2020, 56(6):  1065-1072.  DOI: 10.13209/j.0479-8023.2020.075

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In order to verify the effect of glacial buzzsaw on the evolution of landform in Pulan region of Tibet, three areas of Gurla Mandhata (Naimon’anyi), Himalayas and Gangdese are selected. Based on digital elevation model (DEM) data, remote sensing images, the equilibrium line altitude (ELA) of modern glacier and last glacial maximum (LGM) glacier, the relationship between slope and elevation and the elevation distribution are calculated and analyzed. We conclude that the areas with significant glacier erosion and the most obvious slope reduction are located in the area near LGM glacial equilibrium line and the heights of the mountains are limited in some degree. Based on the glacial landform characteristics and previous investigations, we believe that climate is the most important factor influencing the effectiveness of glacial buzzsaw. During glacial periods, the westerly jets moved southward, wind speed and precipitation increased, and the precipitation increased, resulting in favorable conditions for the development of glaciers and the effect of glacial buzzsaw. For mountains with strong tectonic uplift, such as Gurla Mandhata in the study area, although the effect of glacial buzzsaw is strengthened, the height increase caused by tectonic uplift is not completely offset by glacial buzzsaw.

Evaluation of Rock Desertification Restoration Model in Jianshui County, Yunnan Province

XIAO Linying, WU Xiuqin

2020, 56(6):  1073-1080.  DOI: 10.13209/j.0479-8023.2020.104

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Based on Landsat TM data from 1992 to 2017, the second-class survey data of Jianshui County forest resources and the monitoring data of rocky desertification in Yunnan Province, with Mann-Kendall mutation analysis and trend analysis, the temporal and spatial variation characteristics of vegetation and the restoration of vegetation in different rocky desertification restoration models in Jianshui County of Yunnan Province in the past 25 years were discussed. The study found that during the 25 years, the vegetation cover of Jianshui County showed an overall upward trend with an average growth rate of 0.065%/10a. Since 2008, the growth rate increased from 0.077%/10a to 0.475%/10a. The area of vegetation cover in Jianshui County showed an increasing trend, no significant change, and the proportion of reduction trend was 55.32%, 34.44% and 10.24% respectively. For different restoration models, within the restoration time range of ten years, there was not much difference in the effect of vegetation restoration under the pure ecological forest mode and the mixed ecological forest mode. Within the restoration time range of 25 years, the mixed ecological forest mode vegetation restoration rate was obviously better than pure ecological forest restoration mode, and the advantages were mainly displayed in the later stage of restoration. In terms of species selection of pure ecological forest model, broad-leaved forests and alders had better restoration effects in the short term; in the long run, Yunnan pine and Che sang-tzu were better restoration species. In the mixed ecological forest model, the coniferous mixed forest restoration rate was the best both in the range of ten and twenty-five years, indicating mixed ecological forest model is a better mixed model. The study revealed the effects of different governance models on vegetation restoration, and provided a theoretical basis for optimizing

ecological restoration methods in rocky desertification areas.

Study on the Dust Retention Effect of Common Garden Plants in Shenzhen

YIN Zhuojun, SHEN Xiaoxue, LI Ruili, GAO Huihui, YU Lingyun, ZHOU Lin, WU Hailun, CAO Ye

2020, 56(6):  1081-1090.  DOI: 10.13209/j.0479-8023.2020.096

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Taking six most common garden plants in Shenzhen were used as research objects, the amount of dust retention per unit leaf area and the particle size composition of dust were studied. The microscopic morphology and the structure of leaf surface as well as the composition and distribution characteristics of the retained particles were investigated. The influence of meteorological factors on the dust retention characteristics of plants was clarified. The results showed that: 1) The dust retention amount per unit leaf area of different plant types was Ficus microcarpa (0.74±0.21 g/m²) > Schefflera arboricola (0.42±0.26 g/m²) > Ficus hispida (0.24±0.26 g/m²) > Ixora chinensis (0.20±0.07 g/m²) > Ophiopogon bodinieri (0.18±0.10 g/m²) > Plumeria rubra (0.15±0.10 g/m²). 2) The six types of garden plants were mainly composed of particles with particle size α>10 μm. The weight of particles with size α>10 μm accounts for 59.21%~88.92% (except for F. microcarpa) of the total weight. S. arboricola had the strongest dust-retaining ability for particles with size α>10 μm (0.34±0.20 g/m²). F. microcarpa had the strongest dust-retaining ability for particles with size 3 μm<α<10 μm (0.51±0.15 g/m²) and 0.15 μm<α<3 μm (0.14±0.07 g/m²). 3) Stoma, fold, groove, flocculent protuberance and villi on the surface were conducive to the retention of dust. The main elements of the retained particles were O, Si and Al. 4) The large particles (α>10 μm) detained by the leaves of the six garden plants were susceptible to wind speed and temperature. The results of this study can be used to guide the arrangement of garden plants in Shenzhen and provide a scientific evidence for the plant dust retention effect to improve air quality.

Impact of Urban Village on Job-Housing Balance in Shenzhen: A Study Using Mobile Phone Signaling Data

TONG De, GAO Jing, GONG Yongxi

2020, 56(6):  1091-1101.  DOI: 10.13209/j.0479-8023.2020.069

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Taking Shenzhen as an example and TAZ (traffic analysis zone) as the research unit, by means of multiple linear regression and spatial lag model, using mobile phone signaling data, urban built environment data and so on, the role of urban village in promoting job-housing balance is revealed under the premise of controlling the influence of variables such as built environment on the commuting distance. Main conclusions are as follows. Firstly, the average commuting distance of TAZ with a high proportion of urban villages is relatively short and the existence of urban village is favorable to promote job-housing balance, which is related to the large scale, scattered distribution, low rent, flexible lease period and low income of the tenants of urban villages in Shenzhen. Secondly, built environment also has significant influence on average commuting distance of residents. Increasing the degree of land use mixing, increasing the diversity of built environment, optimizing public transportation and destination accessibility will reduce the average commuting distance of TAZ residents in varying degrees and the average commuting distance of residents in TAZ with good social and economic environment is longer. Thirdly, the commuting distance of residents has obvious spatial autocorrelation.

Influence of Policy-Driven Land Use Transformation on Multifunctional Land Use in the Middle Reaches of the Heihe River Basin

MENG Jijun, ZHU Lijun, WANG Qi, GUO Liren, ZHANG Weijia

2020, 56(6):  1102-1112.  DOI: 10.13209/j.0479-8023.2020.095

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Selecting the middle reaches of the Heihe River as the study area, with a dataset including land cover, geospatial, physical geography and social statistical data, the paper discusses the influence of land use policies on land multifunction from 2000 to 2014, based on land use transformation analysis and assessment on multifunctionality of land use. The results indicate that the land use transformation of the study area is distinct. Land of living doubled in the period and land of manufacture increased by 33%. Ecological land remained unchanged basically. The functions of land doubled. Social and economic functions are the main features of land use and improve a lot. Environmental and cultural functions are weaker than social and economic functions. Land policy has largely affected the land’s multifunctional use. Land development have influenced on employment, manufacture and resource maintenance. Occupied farmland for construction can improve the social security and economic supply function, while the influence of returning farmland to forest and grass on land use multi-function is not significant.

Accessibility of Public Rental Housing to Public Facilities: the Case of Shenzhen

GONG Yue, XUAN Lingyi, SUN Shan, LIN Junqiang

2020, 56(6):  1113-1121.  DOI: 10.13209/j.0479-8023.2020.102

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Using Shenzhen as a case, this paper examines the spatial accessibility of public rental housing to public facilities and its impact factors. First, the spatial distribution of public rental houses in Shenzhen from 2012 to 2017 is analyzed through nuclear density analysis method, and the spatial pattern shows a dual-core clustering called “Qianhai-Shenzhenbei”. Second, ArcGIS and analytic hierarchy process are used to develop an index system of spatial accessibility, and the spatial accessibility of various districts are divided into three levels. Finally, mixed OLS and fixed effect model are used to study the development mode as an impact factor of the spatial accessibility. The result shows that macro policies, development methods and public facilities can affect the spatial accessibility. Among three main types of development modes, urban renewal development has the most significant impact, while the new centralized-built development and the upper cover development have much less impacts.

Water Budget Characteristics of Over-Irrigated Oasis in Arid Region of Northwest China

WANG Bei, YAN Chunhua, WANG Yue, LI Cheng, ZHANG Qingtao, QIU Guoyu

2020, 56(6):  1122-1128.  DOI: 10.13209/j.0479-8023.2020.103

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Based on the water balance equation, a field experiment was carried out to observe the dynamic characteristic of volumetric soil water content during growing season of 2012 and to explore the impact of irrigation on the oasis water budget. The results showed that in the Zhangye oasis, the volumetric soil water content at the depth of 40–60 cm was higher than that at the depth of 0–20 cm during days without precipitation and irrigation. Heavy precipitation has an obvious impact on the volumetric soil water content at the depth of 0–20 cm while irrigation has an obvious impact at the depth of 0–100 cm. The daily evapotranspiration (ET) was 2.83 mm/d during days without precipitation and irrigation. The ET volume of the third day after precipitation increased by 16% compared to the ET volume before precipitation. The ET rate of the second day after irrigation was observed with an increase of 88% compared to the ET rate before irrigation, indicating that the impact of irrigation on ET was more significant than that of precipitation. The primary incomings of the water budget in the oasis was irrigation, which accounted for 89.7% of the total incomings. The main outgoings of the water budget in the oasis was deep percolation (DP), which accounted for 81% of the total outgoings. The irrigation water requirement was only 213 mm during the growing season of 2012, but the real irrigation volume exceeded the irrigation water requirement by 474 mm. Excessive deep percolation and serious water wastage was obvious during growing season due to the heavy irrigation.

Study on the Occurrence Law of Red Tide and Its Influencing Factors in the Offshore Waters of China from 2001 to 2017

ZHANG Shanfa, WANG Qian, GUAN Chunya, SHEN Xiaoxue, LI Ruili

2020, 56(6):  1129-1140.  DOI: 10.13209/j.0479-8023.2020.110

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By collecting and sorting the relevant data from 2001 to 2017, a preliminary study on the rules and influencing factors of red tide outbreaks in offshore areas of China was conducted. The results indicate that the occurrence pattern of red tide in the offshore areas of China increased firstly and then decreased. The area and frequency of red tide in China seas increased significantly from 2001 to 2005, while decreased significantly from 2006 to 2017. From 2008 to 2017, a total of 608 red tides occurred in China, and 65 species were the first dominant species that triggered red tides. Prorocentrum donghaiense was the organism that caused the most red tides, 106 times totally. The influencing factors of red tide in each sea area were different: the changes in red tide area in the Bohai Sea were mainly affected by nutrients and total nitrogen; the changes in area and frequency of red tide in East China Sea were significantly affected by nutrients, total nitrogen, total phosphorus, and nitrite nitrogen; the changes in the area of red tide in South China Sea were significantly positively correlated with pollutants entering the sea and CODcr (P<0.05). In order to further reduce red tide outbreaks, several suggestions were proposed for prevention and control of red tide in offshore areas of China: establish online monitoring stations; take control measures based on local conditions; strengthen source pollution management; improve emergency response systems; carry out marine ecological restoration.

Analysis of Rural Development Status and the Poverty Alleviation Project from the Perspective of Rural Revitalization in Jiangjin District of Chongqing

ZHU Wenjie, LIU Lulu, GAO Yang, FAN Xu

2020, 56(6):  1141-1151.  DOI: 10.13209/j.0479-8023.2020.105

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Taking Jiangjin District of Chongqing as an example, from the perspective of the rural revitalization strategy, the pre-diagnosis before the project implementation is carried out by constructing the analysis framework of “rural development status evaluation-type of country-pre-evaluation of poverty alleviation project” to identify the advantages and disadvantages of rural development. The results show that the average evaluation of the overall planning in Jiangjin District is 0.080, and high-value area is mainly distributed in the north and east of Jiangjin District. The average evaluation of infrastructure in Jiangjin District is 0.819, forming a southern low-value surrounding zone. The average evaluation of living environment is 0.713, forming a southern high-value surrounding zone and a northern low-value zone. According to the current development status, 241 villages in Jiangjin District can be divided into 15 types. The largest number of “planned general-foundation-generalenvironmental general” type is 64, scattered in the northern part of Jiangjin District. The number of poverty alleviation projects implemented in this type of village is 12, which is significantly more than other types of villages. The implementation of the poverty alleviation project in Jiangjin District is mainly concentrated in the west and the south. From the perspective of the type of rural development in the Jiangjin District and the implementation of each project, the improvement of the integrated planning and infrastructure poverty alleviation project has a higher matching degree with the rural development, but the poverty alleviation project to improve the living environment is only 3.

Review of Regionalization and Remote Sensing Based Method for Hydrological Model Parameters Calibration in Ungauged Basins

JIANG Lulu, WU Huan, Lorenzo Alfieri, LI Xiaomeng, John S. Kimball, CHEN Xiuwan

2020, 56(6):  1152-1164.  DOI: 10.13209/j.0479-8023.2020.076

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Challenges in calibration of hydrological model parameters in ungauged basins were discussed, and the latest advances in regionalization method and remote sensing based method were summarized. First, the common problems in the hydrological model calibration (derivation of hydrographic parameters, construction of objective function and selection of optimization method) and their influences on the results of parameter optimization) were analyzed and leading-edge solutions were then provided. Next, fundamental principles and study progress of regionalization method were introduced, and the importance of stream gauge network density of donor catchments for the streamflow prediction was emphasized. The advance of remote sensing based hydrological model calibration method was discussed in terms of model spatial domain, model structure, satellite data source, and

calibration target. Finally, the advantages and disadvantages and the future development prospect between regionalization method and remote sensing based method were compared and analyzed, and potential practical strategies for continuous streamflow prediction in ungauged basins in China are suggested.

Evaluation of Technologies Improving Translation Coverage of TLB Using Continuity of Memory Mapping

BAN Yikun, ZHANG Weiqi, ZHOU Yuchen, YI Jiangfang

2020, 56(6):  1165-1168.  DOI: 10.13209/j.0479-8023.2020.101

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The authors define and evaluate the continuity distribution in memory mapping of some typical benchmark programs, and verifiy the existence of multiple types of continuity (mixed continuity) in memory mapping of programs. Furthermore, some technologies using continuity of memory mapping to improve translation coverage of TLB are evaluated. It is found that the existence of mixed continuity limits the actual effect of existing technologies in real scenes.