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The nonlinear remote sensing ecological index (nRSEI) is a recently proposed eco⁃ logical index, which used the kernel principal component analysis (kPCA) algorithm to integrate four indica⁃ tors of the existing remote sensing ecological index (RSEI) rather than using the traditional principal compo⁃ nent analysis (PCA) technique. The main reason for using kPCA was that in the Beijing area the correla⁃ tions between wetness, greenness, dryness, and heat that are four indicators used in RSEI were generally weak, so the kPCA that is specially developed to deal with variables with nonlinear relationship was needed to handle these four non-linear indicators. This paper aims to examine the correlation strength of these four indicators in the Beijing area to see whether their relationship is strong or weak and analyzes the effective⁃ ness of the accuracy assessment method that was used for the validation of the new index. Methods: Through examining correlation coefficients and scatter diagrams, the correlation between the four indicators is investigated to find out whether the relationship between the indicators is linear or non-linear. Also, the effectiveness of the validation for the new index is analyzed. Results: The results show that the four indica⁃ tors are strongly linearly correlated with each other, therefore, the kPCA was not suitable for the intergra⁃ dation of the four indicators. The methods used for the accuracy assessment of the new index also have obvious defects and thus failed to effectively validate the accuracy of the new index. In addition, some important issues related to prepare remote sensing papers are also discussed. These include the feasibility of remote sensing modeling, the robustness of the model, the scale consistency of the sub-indicators in the model, the validation method for the model, the selection of reference images for the validation, and the required sample size for accuracy validation. Conclusions: The nRSEI is not a suitable index for the assessment of regional ecological status as it mistakenly employed kPCA to intergrade the four indicators that are linearly related. [ABSTRACT FROM AUTHOR]

With the launch of the "Channel Computing Resources from the East to the West" project, Beijing-Tianjin-Hebei region, as a national integrated big-data center system, has established a Zhangjiakou data center cluster and continuously optimized the regional computing power layout. Beijing has been accelerating the construction of a global digital economy benchmark city since 2021, committed to forming a collaborative development pattern of computing power integration, and achieving a globally leading density of data centers. The core industry of Beijing's digital economy has strong fundamental advantages, but as a high-energy consuming industry, data centers cannot fully meet real-time computing power needs solely relying on the local infrastructure construction in Beijing. Therefore, this paper explored the promoting role of the Beijing-Tianjin-Hebei national integrated big-data center system in the construction of a global digital economy benchmark city in Beijing through channels such as computing power resource sharing, green energy consumption support, and industrial development collaboration. Based on this, it analyzed the challenges that still exist in current regional collaboration. [ABSTRACT FROM AUTHOR]

Objective To observe the classification of nasal dorsal lines in Chinese population and explore the corresponding precise treatment strategy. Methods From July 2021 to September 2022, 238 patients (201 female and 37 male) receiving treatments for nasal dorsal lines in the Department of Plastic and Reconstructive Surgery of Peking Union Medical College Hospital were enrolled. Before the injection, photographs were captured at rest and at grimace under the standard conditions, then the nasal dorsal lines were classified. Six regular injection points were selected. The injection dose at each point was adjusted according to the specific wrinkle type. Follow-up was performed at 3 to 5 weeks after injection. The treatment effect was evaluated by Facial Wrinkle Scale. Complications were also recorded. Results Among the patients included, 88 cases were complex type (37.0%), 70 cases were transverse type (29.4%), 52 cases were oblique type (21.8%), and 28 cases were vertical type (11.8%). The average preoperative wrinkle score was (2.50±0.50), and the postoperative wrinkle score was (1.03±0.54), with a significant difference (P<0.05). Fourteen patients had bruising and 9 patients had slight asymmetry of lips when smiling. No other serious complications were recorded. Conclusion The nasal dorsal lines of Chinese people can be categorized into complex, transverse, oblique, and vertical types. The precise treatment strategy adopted in this paper has good clinical effect. [ABSTRACT FROM AUTHOR]

【Objective】By studying the hyperspectral characteristics of apple damage and establishing the best classification model of apple damaged area based on hyperspectral imaging, we can provide an important basis for realtime, rapid and accurate identification of apple damage.【Method】This paper investigates the use of hyperspectral image technology to detect mechanical damage on fruit surfaces using apple samples collected from Pinggu District, Beijing as the research object. Using the hyperspectral image (HSI) data in the range of 390-1 000 nm, the spectral response characteristics of the damaged and normal ROI areas was analysed by ratio spectroscopy, and three types of spectral indexes, namely the normalized difference spectral index (NDSI), the ratio spectral index (RSI) and the difference spectral index (DSI) were selected and constructed to better highlight the characteristics of the damaged areas..On the basis of these indexes, the spectral indexes with better ability to extract damage areas were selected, and the unsupervised data clustering algorithm of iterative self-organizing data analysis techniques algorithm (ISODATA) was used to extract apple damage areas.【Result】 The spectral reflectance changed significantly when the apple surface was damaged. After waveband optimization, it was found that the reflectance of 528 nm and 676 nm could effectively identify the abnormal areas. Based on the selected feature bands, the recognition spectral indexes for apple damage detection were constructed, including NDSI, RSI and DSI. By the pixel value analysis of the spectral index images, the damaged area features were distinguished from the normal area features in each SI enhanced image obviously. Among them, the difference between the NDSI pixel averages of the two types of image features was the largest, reaching 0.629, which indicated that the established NDSI has a strong ability to distinguish between the damaged area and normal area features. Using the unsupervised classification method ISODATA classification, it was verified that the spectral feature index has high specificity in detecting apple damage, and the accuracy rate of apple damage reached 92.50%. 【Conclusion】The results are applicable to the real-time and rapid detection of apple damage, providing a technical basis and reliable reference for the accurate management of apple production. [ABSTRACT FROM AUTHOR]

Taking 13 cities in Beijing, Tianjin and Hebei as the research objects, this paper constructed the urban smart development index system from three aspects: smart space construction, smart element allocation and smart welfare performance, measured the urban smart development level in Beijing, Tianjin and Hebei from 2008 to 2018, and used ArcGIS software to realize the temporal and spatial measurement performance of smart development level. The obstacle degree model was used to reveal the criterion-level factors that hinder the smart development of Beijing, Tianjin and Hebei cities. The main conclusions are as follows: (1) The smart development level in Beijing, Tianjin and Hebei is low, the research period shows a weak fluctuation and downward trend, and there is room for improvement. (2) From the spatial difference of smart development level, the double core trend with Beijing and Tianjin as the high level is obvious, showing a downward trend from the center to the surrounding. (3) From the overall barrier performance of study area, smart welfare performance accounts for the largest proportion, smart space construction takes the second place, and smart factor allocation is the lowest. (4) The obstacles to smart development in different cities vary. The obstacles in Beijing and Tianjin are mainly focused on smart welfare performance. As the main core area to undertake Beijing's noncapital functions, smart space construction and smart element allocation are the obstacles in most cities. [ABSTRACT FROM AUTHOR]

(1) Background--As a significant ecological safeguard measure, the new round of returning farmland to forests project is of great ecological significance for ecological protection in Beijing and Tianjin. However, as a policy measure involving the withdrawal of farmers' cultivated land, whether it can guarantee the continuous in-crease of farmers' income and the stability of farmers' consumption is more worthy of discussion. (2) Methods--Based on the micro-panel data of 1115 farmers from 223 rural households in the "Beijing-Tianjin Sandstorm Source Treatment Project Monitoring" project from 2013 to 2017, this paper used the random effect model and the mediating effect model to study the impact of the new round of returning farmland to forests on the rural households' income and consumption and the effect mechanism on the rural households' consumption. (3) Results--The new round of returning farmland to forests significantly increased the total family income of the rural households, and had a significant positive impact on the total family income and operational income of the rural households at the level of 10%. However, the new round of returning farmland to forests did not improve the income structure of the rural households, and did not significantly affect the wage income, property income and transfer income of the rural households. The factors such as the farmers' education level and the number of migrant workers had a significant positive impact on the wage income. Overall, the income of the rural households was still dominated by operational income. The new round of returning farmland to forests significantly increased the total family consumption of the rural households, especially the basic consumption and productive consumption. However, there was no significant increase in children's education consumption, medical consumption and interpersonal communication consumption, which also indicated that the consumption structure of the rural households was still in basic consumption. The new round of returning farmland to forests had a positive impact on the rural households' consumption through the mediating variable of increasing the rural households' income, which verified the transmission mechanism that the farmers participated in the new round of returning farmland to forests to promote the increase of their income, and then affected their consumption. (4) Conclusions and Discussions--First, appropriately raise the subsidy standards and improve the compensation mechanism. Especially for areas prone to return to poverty and ecological functional areas, reasonable compensation standards can make up part of the losses caused by the farmers' participation in the project of returning farmland to forests. In addition, the government can implement a dynamic compensation mechanism according to the actual local situation, so that the subsidy standard is in line with the actual social and economic development situation. Second, actively promote the centralized utilization and circulation of the remaining finely fragmented land through the separation of the three rights of land. On one hand, the circulation of the fragmented land can improve the utilization rate of land, on the other hand, it can promote the flow of labor forces, so as to promote the increase of the rural households' income and the improvement of consumption structure. Third, actively implement the reform policy of forest rights, ensure clear rights to the rural households, and fully improve the promotion role of property rights income on the farmers' willingness to return farmland to forests. In addition, the farmers can also use forest rights as collateral to obtain loans to inject financial impetus into forestry production. Fourth, encourage the development of undergrowth economy and develop three-dimensional agriculture such as fruit industry, under-forest breeding industry, forage-grass planting industry, medicinal materials planting industry according to local conditions. However, while developing the corresponding undergrowth economy, we should also pay attention to the maintenance of forest nutrients, which is conducive to the sustainable and circular development of forestry. [ABSTRACT FROM AUTHOR]

This article explained the definition and attribute of municipal sludge in Beijing, analyzed the production and discharge characteristics and studied the development course of disposal and utilization of municipal sludge in Beijing. The results show that the development of Beijing municipal sludge disposal and utilization mainly includes three stages, the first stage before 1999, started sludge drying and stumping fertilizer; the second stage from 1999 to 2012,the slow development stage of disposal and utilization, the demonstration plant of sludge treatment was established, using various drying technologies and incineration treatment modes; the third stage is from 2012 to now, the sludge treatment technology in the central district of city is the advanced anaerobic digestion of thermal hydrolysis, and the disposal mode is mainly land use, forming a typical Gao Antun sludge treatment mode. On the basis of the current situation of municipal sludge treatment in Beijing, this paper summarizes relevant policies and technical standards of sludge treatment in Beijing, and introduces the new progress of low-carbon and green transformation of municipal sludge disposal in Beijing which provides certain reference and reference for the treatment and disposal of municipal sludge. [ABSTRACT FROM AUTHOR]

Peking duck is a local breed unique to Beijing, which has been officially obtained the registration certificate of agricultural product geographical indication in 2017, and Peking duck has been selected the second batch of mutual recognition orders of EU-China agreement on geographical indications. In recent years, Beijing General Station of Animal Husbandry has carried out in-depth work in management and technical research as the holder of Peking duck certificate of agricultural product geographical indication. In order to fully implement the major decisions and plans made in the Report of 20th National Congress of the CPC on comprehensively promoting rural revitalization and accelerating the building of an agricultural powerhouse, to promote the high-quality development of agricultural product geographical indication of Peking duck and help rural revitalization of Beijing, the construction of whole industrial chain standard system is urgent. The input management in Peking duck farms is one of the key links of standardized production control of industrial chain. The paper reviews the input management importance and the study on technical specification of agricultural product geographical indication of Peking duck, to provide reference for the breeding of Peking duck. [ABSTRACT FROM AUTHOR]

Based on Beijing's air quality data and socio-economic data from 2015 to 2020, Kernel density estimation, spatial autocorrelation and random forest methods were used in this paper to analyze the air quality characteristics and influencing factors in Beijing from 2015 to 2020. The results showed that the concentration of particulate matter contributed the most to the change of AQI in six pollution components of air quality; the difference in air quality in the four seasons was decreasing; air quality was obviously related to social production activities and governance rules. As a whole, the Air Quality Index(AQI) in the north of the municipal area was low, while the air quality in the south was relatively high. The increase in per capita disposable income, green coverage area and scientific research funding could effectively reduce the degree of air pollution. [ABSTRACT FROM AUTHOR]

Based on the engineering background of the left line of shield repair open tool change between Chaoyang Port station and Shilihe Station of Beijing metro line 17, this paper introduces a new method of shield machine shield repair open tool change. In this paper, the reason and construction risk of the project are analyzed, and the construction process, construction parameters, control measures and final implementation effect of the method are introduced in detail. The diameter of shield machine changes, the size of plain concrete wall can be adjusted according to this method, which can provide technical reference for similar projects in the future. [ABSTRACT FROM AUTHOR]

In cities, the main source of air pollutants is vehicle exhaust. It has become an urgent problem for many cities to explore the law of vehicle exhaust diffusion and actively seek for improvement measures. At present, there are many researches on the simulation of vehicle exhaust diffusion, but few on the modeling of diffusion process and volume visualization analysis. This paper integrates California line source dispersion model‐4(CALINE4) model and 3DGIS to solve the problem of urban vehicle exhaust diffusion simulation and dynamic visualization. Firstly, a street‐scale framework of vehicle exhaust diffusion simulation and visualization is established, and a continuous concentration field is established to express the diffusion processing. A unified data model is used in the semantic space to integrate the data of buildings, roads, trees and dynamic diffusion process data. Secondly, a graphics processing unit ‐ based direct volume rendering method is used to visualize the dynamic diffusion data, and this algorithm is improved in real‐time gradient calculation, texture sampling and time‐based interpolation. Finally, this paper analyzes the vehicle exhaust diffusion of a road in the central business district area of Beijing. The experimental results show that the coupling application of 3DGIS and CALINE4 model can better reveal the spatial and temporal distribution characteristics of urban vehicle exhaust and concentration, which verifies the reliabless and efficiency of the proposed method. [ABSTRACT FROM AUTHOR]

With the implementation of clean energy heating project in rural areas of northern China, the pollution of coal-fired heating in winter has been greatly improved. However, the use of large-scale electric heating equipment put forward new challenges to the power supply reliability of low-voltage distribution network. Especially in rural power grid, the load is heavy in winter and low in other seasons. It is one of the effective measures to achieve optimal resource allocation and improve the power supply quality of the distribution grid to exploit the demand response potentialities of electric heating loads, and motivate electric heating loads to actively respond to demand response programs (DRP) for peak-load shifting. Therefore, a load optimal control strategy for rural electric heating equipments based on demand side peak load regulation was proposed in this paper. A market transaction model was designed for third-party agency companies to represent coal-to-electricity users in the peak shaving market. The agency company made the centrally control strategies of electric heating users’ equipment according to the peak shaving volume and corresponding price obtained from the peak shaving market bidding. The electric heating users were classified based on the controllability of each user by the agency company. Each kinds of users could get different compensation price to encourage them to participate in the demand response programs for peak-load shifting. In this market model, a multi-objective optimization model was established to control the users’ air source heat pump. The goals of the optimization model were to meet the user's temperature demands to the maximum extent and to maximize the benefit of the agent company. Meanwhile, user's comfort requirements for indoor temperature were considered in this model, and the user classification compensation mechanism was introduced to improve the user's initiative to participate in peak load regulation. Taking the load data of electric heating users in Pinggu District of Beijing as an example, the simulation analysis was carried out. The results show that the total load reduction of all electric heating equipment was 159.773 kWh, there was no over-control for anyone user, the load reduction of each user fluctuated around average reduction of 7.989 kWh, the peak valley of the user's power consumption curve was changed, the optimal control strategy proposed in this paper played the role of peak load reduction and valley filling, which can relieve the pressure of the upper power grid during peak load period. The indoor temperature of the users was (18±1) ℃, which meet the demand of comfortable temperature for heating in winter. Compared with the target of not considering the benefit, the one-day compensation cost of the agency company was saved 31.9%, and the users with the highest degree of control got the most compensation income, the peak load regulation strategy could encourage the users to participate in the peak load regulation actively. [ABSTRACT FROM AUTHOR]

The temperature in edible fungi greenhouse has the characteristics of time-variant, nonlinear and multi-coupling, so accurate and effective temperature predictions can effectively help growers adjust the greenhouse environment and prevent edible fungus production and quality decline. Based on the perspective of mining the time-series information in historical temperature data. This paper described the specific steps to realize the MA-ARIMA-GASVR-based hybrid combination method to predict the temperature in the edible fungus greenhouse. Firstly, we assumed that the historical temperature series data of edible fungus greenhouse was a dynamic combination of linear and non-linear components, the historical temperature sequences were decomposed into linear sequences and residual sequences using the moving averages (MA) method. Then, time series analysis was conducted to established the model of the autoregressive integrated moving average (ARIMA) by using linear sequence after the decomposition of the moving averages, and the future trend of linear sequences was predicted by the established model. Afterward, to better fit the relationship between temperature trends and various noises in the environment, the autoregressive integrated moving average model prediction value, the historical residual data and the historical temperature data were employed as the input of the support vector regression (SVR) model, and the genetic algorithm (GA) was used to optimize the parameters of the support vector regression model to improve its performance, the parameters being optimized are penalty parameter and radial basis function kernel parameters in the support vector regression model. Finally, the hybrid model output was the temperature prediction value which was more in line with the actual situation. Moreover, the hybrid method was verified using the experimental data from the edible fungus greenhouse in Beijing. In this paper, a representative edible fungus greenhouse was selected as the experimental object according to the observation time requirements and the time-varying needs of edible fungus greenhouse temperature, which was located in the Daxing District of Beijing. A total of 2 208 measured edible fungus greenhouse temperature data were collected from July 1st, 2019 to September 30th, 2019 during the experiment. The experimental data acquisition device used the JXBS-7001 temperature monitoring sensor was used to automatically collect and record the experimental data. Three sets of sensors were deployed in the edible fungus greenhouse to record the experimental data set which included the average temperature data. We trained the proposed model by using data from July 3rd, 2019 to July 16th, 2019 and forecasted the temperature of the next two days and compared temperature prediction experiments with different models and different time intervals. The results indicated that the MA-ARIMA-GASVR-based hybrid model could better fit the original temperature data, the mean squared error, the mean absolute error and mean absolute percentage error of an hour interval temperature were 0.18, 0.36, 1.34, and three error evaluation indexes all showed that the prediction accuracy of the hybrid method in this paper was better than the single models of support vector regression and support vector regression optimized by genetic algorithm, and it was also superior to the hybrid methods which were not processed by moving averages method or optimized by genetic algorithm. Besides, the mean squared error, the mean absolute error and mean absolute percentage error of 6hours interval temperature were 0.29, 0.52, 1.95. the hybrid method in this paper can satisfy the multi-step prediction within 6 hours, which could provide more time for edible fungus producers to adjust the temperature in the greenhouse. [ABSTRACT FROM AUTHOR]

It is necessary to scientifically divide village lands and further propose a differentiated governance strategy, which is the premise and basis to plan village development and reduction of construction lands. Generally, the village land is characterized by “large amount, scattered layout, low efficiency and poor environment”. Beijing has entered the era of “reduction development”. In Miyun District, the lands are governed scientifically, and it is of great significance to optimize ecological spatial pattern and protect ecological environment. The renovation of village land is a complex and systematic project, which is affected by the natural environment conditions, economic development level, development and construction conditions and location conditions of rural areas. Taking Miyun District of Beijing as a case, based on land use, points of interest and social statistics data, this paper constructed a land suitability evaluation model in view of natural conditions and land patterns. Moreover, the evaluation model was built for village development status from four angles - location conditions, infrastructure，ecological conditions and resource industry，then systematically analyzed village land suitability, village development status and their combination, and divided the type of village lands in the end. The results showed that: 1) The suitability index of village land in Miyun District is between 33-97, the village lands in Miyun District were mostly suitable, but in a trend of decreasing from southwest to northeast; 2) The village development index of Miyun District is between 22.2 and 78.7, villages with higher development index were mainly located in the area around Miyun city in the southwest region, followed by the central part around the Miyun reservoir area, and those in northern area were underdeveloped; 3) based on the evaluation results of both, the village lands in the whole district were divided into nine groups that were further classified into four village types. Among them, the area around Miyun city in southwest was filled with urbanization development types, where it was appropriate to implement governance strategies on urbanization development; in eastern and northern regions, there were villages of adjusted-optimization development types, and governance strategies for adjustment and optimization could be applied; accordingly, the construction and improved development types were mainly distributed around the urbanization development types in the southeast and surrounding areas of Miyun reservoir, with the orientation as construction, improvement and development. In addition, one could find that the villages of reduced development type were available in the northeast and northwest of Miyun District, and it was recommended that reduction development strategy could be implemented. Through research, the author provided the technical basis for the efficient and orderly utilization of village lands. Undoubtedly, village governance aims not only to achieve “reduction”, but also “increase” in some areas, as the healthy development of a village depended on both increase and decrease. In a word, village governance is so complicated that it involves in many aspects and multiple departments. In this paper, the author divided village lands based on village development and village land suitability. The research results were of reference value to provide methods on regional village development planning and reduction of construction lands. However, to be frank, the specific governance measures should also take macro development policies and public preferences into account. [ABSTRACT FROM AUTHOR]

Generally speaking, Laoshe is a writer who tended to incorporate heavy local color into his own works. However, there is an important phenomenon in China’s literary history that Laoshe intentionally abandoned his depiction of Beijing’s local color in his writing in the early period of the Anti-Japanese War and stopped writing in his most skilled Beijing dialect. It’s not until around 1943 that Laoshe restarted to bring Beijing’s local customs into his novel writing. In this paper, the author tries to interpret this literary phenomenon by analyzing the reasons why Laoshe reused local color in his 1940s writing. In the final part of this paper, the author concludes that the reason why Laoshe abandoned Beijing’s local color in his writing in the early period of Anti-Japanese War is that he worried that the depiction of a certain region might not reflect the new image of Chinese people in Anti- Japanese War thus couldn’t encourage the whole nation. However, in around 1941, with Laoshe started to regard local color as an effective carrier and means of narration, the application of Beijing’s local color again became the most important characteristic of his works. [ABSTRACT FROM AUTHOR]

To address the uncertainty of surgery duration, this paper investigates surgery planning scheduling problem with multiple servers, which proposes chance constraints of operating rooms overtime to guarantee the surgery durations of patients is no more than the time limit of operating rooms with a high probability. A stochastic chance-constrained program is proposed to determine which operating rooms to operate, and surgeries to operating rooms allocation. Based on a finite support set of the surgery duration, this paper introduces 0-1 variables to formulate the chance constraints, and derives 0-1 integer linear program counterpart. To improve the efficiency of the model, this paper presents two classes of valid inequalities and uses the longest path algorithm to separate the second class of valid inequalities, which are implemented in a branch-and-cut framework. Computational experiments based on real-life data from hospital in Beijing are conducted to verify the algorithm performance and determine the optimal planning scheme, so as to take full utilization of healthcare resources, i.e. operating rooms. [ABSTRACT FROM AUTHOR]

Reliable traffic flow prediction is of great significance in traffic management and public safety. However, this is also a challenging task because it is affected by spatial dependencies, temporal dependencies and some additional factors (weather and emergencies, etc . ) . Most existing works can only consider part of the attributes of traffic data, resulting in insufficient modeling and unsatisfactory prediction performance. This paper proposed a novel end-to-end deep learning model, called spatio-temporal attention ConvLSTM ( ST-AttConvLSTM ), for traffic flow prediction. ST-AttConvLSTM was divided into three branches for modeling. For each branch, the residual neural network was used to extract local spatial features, and external factors were also combined with them. Then, it employed two components consisting of ConvlLSTM and attention model to discover the potential relationship of traffic flow, and capture the correlations of data in both spatial and temporal dimensions. It used two real trips data sets in Beijing and New York to evaluate the proposed method . The experimental results show that this method achieves higher prediction accuracy than well-known baselines. [ABSTRACT FROM AUTHOR]

The paper starts from the analysis of the growing gap between traditional Chinese bibliography and modern academic development, and it will probe into the original intention of the distribution of Chinese catalogue cards of National Library of Peiping, namely the underlying motivation for Yuan Tung-Li's modern catalogue idea. Next, it depicts National Library of Peiping's early attempts, its active participation in the American academic circles as well as the compilation and distribution of Chinese catalogue cards with the support of the Rockefeller Foundation. Lastly, this study also discusses National Library of Peiping's influence upon the arrangement and categorization of the Chinese collection in American libraries. [ABSTRACT FROM AUTHOR]

This paper introduces a method which utilizes global navigation satellite system (GNSS) based precision point positioning (PPP) for conducting long-term tilt and settlement monitoring of high-rise buildings in North China. Two-year continuous GNSS observations from two high-rise buildings near a deep foundation pit in Beijing are used for the case study. The method comprises four steps: ① Calculating the geocentric coordinates (XYZ) of the GNSS antenna with respect to a global reference frame (e.g., IGS08) with the PPP method; ② transforming the geocentric coordinates to a regional reference frame − the North China reference frame (NChina16); ③ converting the geocentric XYZ coordinates to a station-centric East -North- Up (ENU) coordinates; ④ removing seasonal ground-surface deformation from the ENU time series and restoring the true displacements (tilt and settlement) of the building. Experimental result indicates that the PPP method is able to achieve 2-3 mm horizontal accuracy(root mean square error) and 6-9 mm vertical accuracy (root mean square error)for 24 - hour continuous observations in North China. The combination of PPP, NChina16, and the North China seasonal ground deformation model can perform millimeter-accuracy, nearreal time, and long term static structural health monitoring of high-rise buildings and other large-scale infrastructure projects in North China. [ABSTRACT FROM AUTHOR]

The rapid acquisition of soil water content (SWC) in field crop root zone is significant for drought supervision and precision irrigation. The UAV multispectral remote sensing system has the advantages of obtaining high spatial-temporal resolution of crop phenotype data, and has a wide application prospect in soil moisture monitoring. In order to obtain SWC accurately and timely at a farm scale, in this paper, the field maize with different water treatments is taken as the research object, and the multispectral remote sensing monitoring of summer maize is carried out by using the UAV remote sensing platform, and the soil water content of different soil depth in maize root zone is collected synchronously. Based on the UAV multispectral remote sensing image data sets of jointing stage, tasseling-silking stage and milky-maturity stage of summer maize in 2018, the soil background is removed by support vector machine classification, the spectral reflection of maize canopy is extracted, and the 10 vegetation indices are calculated, then the sensitivity analysis of soil water content in different depth is carried out by using full subset screening method for different wave bands and vegetation indices, and the soil water content in different depth is analyzed respectively, ridge regression and extreme learning machine are used to construct quantitative estimation models of soil water content at 0-20, 20-45 and 45-60 cm soil depth after full subset selection. The test area is located in Zhaojun Town, Dalate Banner, Ordos, Inner Mongolia, China(40°26'0.29" N, 109°36'25.99" E, elevation 1 010 m). The sowing time of maize is on May 11, 2018, the emergence time is on May 18, and the harvest time is on September 8, 2018. The total growth period is 114 days. The UAV multispectral remote sensing images and ground data collection dates are July 8, July 12, July 17, July 21, July 26, August 2, August 28 and September 7, 2018. It is collected once a day and tested 8 times in the whole growth period. July 8-21 is the jointing stage, July 26-August 2 is the tasseling-silking stage, August 28-september 7 is the milk-maturity stage. The flight altitude of the UAV is 70 m, and the flight time is 11:00-13:00 local time (11:44-13:44 Beijing time). Firstly, the UAV multispectral canopy images of field maize with 5 different irrigation treatments (TRTs) are acquired through the six-rotor UAV equipped with a RedEdge multispectral camera ( MicaSense, USA), and the multispectral images of diffuse reflector (reflectivity 58%, size 3×3 m) are collected at the same height to perform radiometric correction in the meantime, and then the spectral reflectances of the field maize are acquired. Secondly, the support vector machine (SVM) is used to eliminate the multispectral image of soil background in ENVI and ArcGIS software, then the maize canopy spectral reflectance is extracted and 10 vegetation indices (VIs), such as Normalized Difference Vegetation Index (NDVI), Normalized Green Difference Vegetation Index (GNDVI) and Transformed Chlorophyll Absorption In Reflectance Index(TCARI), etc, are calculated. Finally, the full subset selection method based on Bayesian Information Criterion (BIC) is used to analyze the sensitivity of SWC at different depths for different spectra bands and vegetation indices in R3.5.1 software, and then Ridge Regression (RR) as well as Extreme Learning Machine (ELM) are used to construct a quantitative estimation model of SWC at soil depths of 0-20, 20-45 and 45-60 cm at different growth stages, respectively. The results show that the full subset selection method based on BIC can effectively select the optimal spectral subset, and the selected variables generally pass the significance test and the independent variables number is small; the effects of the ELM model outperformed the RR model almost under all the same conditions; the optimal monitoring soil depth of maize at jointing stage, tasseling-silking stage is 0-20 cm, and the optimal monitoring soil depth of milk-maturity stage is 20-45 cm; the ELM inversion model at 20-45 cm soil depth at milk-maturity stage has the best effect, the decision coefficients of modeling set and verification set are 0.825 and 0.750, respectively, the root mean square error are 1.00% and 1.32%, respectively, and the normalized root mean square error are 10.85% and 13.55%, respectively. The combination of full subset selection method and machine learning can improve the inversion accuracy and robustness of SWC. This study provides a new way for rapid and accurate monitoring of SWC in farmland and precise irrigation. [ABSTRACT FROM AUTHOR]

Egg price has been attracting public attentions from every community in Beijing market. It is necessary to obtain timely information for the fluctuation of the future egg price, particularly on the demand and supply of table eggs for human consumption. A lot of efforts have been made to accurately forecast future egg price in short, medium or long terms. However, there are many factors affecting egg prices to make the prediction challenging. In this paper, a hybrid model was proposed to forecast egg price by combining seasonal-trend decomposition procedures based on loess (STL) and long short-term memory (LSTM), denoted as STL-LSTM. In decomposition, a time series can be splitted into three components: seasonality, trends and remainder fluctuation. A more stable variance can be obtained from the non-linear, seasonal and periodic each part of egg price. Then, LSTM can be used to capture appropriate behaviors and predict precisely the trends and remainder parts of egg price, respectively, while the seasonal-naïve method can be used to predict seasonal trends in a 12-month cycle. The results from three parts were summarized into a total price forecast. The egg price data that used in this study were collected from the China animal husbandry, covering from January 2000 to December 2018 in Beijing egg markets. The monthly data from January 2000 to December 2017 were used as training set, whereas the 12 monthly data in 2018 were used as testing set in the proposed model. The method was evaluated by using the relative error (RE), root mean square error (RMSE) and the mean absolute error percentage (MAPE). The results show that there was an overall upward trend for the egg price in the Beijing market from January 2000 to December 2018, with the seasonal fluctuation of “low spring and high autumn”, and random fluctuations. The decomposition indicated that the trend component was the main contributor to egg price fluctuations, where the contribution rate decreased from 71.18% to 56.84% during the test period. The influence of seasonal and remaining components on egg prices increased in recent years, with the contribution rates of 34.24% and 8.92%, respectively. In STL-LSTM model, when the step size was given as 1, 3 and 6, the evaluating indexes were optimum: the relative error of 3.67%, 6.49% and 7.22%, the root mean square errors of 0.19, 0.33, and 0.43, and the average absolute percentage errors of 1.91, 3.53, and 4.58. In terms of the evaluating indexes, the proposed STL-LSTM model demonstrated most efficiency to predict egg prices, compared with the previous models, such as separate LSTM, support vector regression (SVR) and the autoregressive integrated moving average (ARIMA). The proposed model can be expected to extend on price predictions of other similar agricultural product in the future. The findings can provide a great potential to accurately forecast the future egg price for market strategies in animal husbandry. [ABSTRACT FROM AUTHOR]

Land use changes can affect the ecosystem services. Since the implementation of reform and opening- up policy in 1978, the transformation and development of society and economy has led to the land use transition, and furthermore led to the "ecosystem services transition". Based on the data of LUCC, net primary productivity (NPP) and statistics in 1980, 2000 and 2015, this paper analyzed the changes and spatial patterns of two types of ecosystem service, e.g., food production, carbon sequestration and oxygen release, in the Beijing-Tianjin- Hebei region by using the methods of GIS and ecosystem service values calculation, and revealed the reasons for the "ecosystem services transition". The results show that: (1) In the past 35 years, the land use changes in the study region was mainly characterized by the expansion of construction land and the decrease of cultivated land. The phenomenon of conversion of cultivated land to construction land was particularly prominent in this region. Between 1980- 2000 and 2000- 2015, the cultivated land in mountainous areas changed from decrease to increase and the forest land changed from decrease to increase. The cultivated land in dam areas continued to increase and the forest land changed from decrease to increase. Both the cultivated land and forest land in plain area continued to decrease. In 1980 and 2000, areas with high values of NPP were mainly located in mountainous areas, and in 2015, they were mainly found in plain areas. (2) From 1980 to 2000, the ecosystem services in the study area were mainly reflected by the increase of food production service and the decrease of carbon sequestration and oxygen production service. From 2000 to 2015, the ecosystem services in the region were mainly featured by the simultaneous increase of food production function and carbon sequestration and oxygen production function. The pattern of "ecosystem service transition" was "food production + carbon sequestration and oxygen production - " → "food production + carbon sequestration and oxygen production + ". (3) The main reasons for "ecosystem services transition" were the improvement of agricultural productivity, the increase of area and quality of forest land, and the increase of the quality of cultivated land and grassland. In general, the "ecosystem services transition" in the Beijing-Tianjin- Hebei region has a positive impact on food security. It is particularly necessary to pay attention to areas where both food production function and ecological function declined. Policies aimed at improving agricultural productivity should be formulated, while policies for supporting ecological restoration should be continued. [ABSTRACT FROM AUTHOR]

In this paper, energy performance of a loop-heat-pipe (LHP) type solar photovoltaic/thermal (PV/T) heat pump water heating system is studied to evaluate its feasibility in three different climatic regions. A mathematic model of this system in our former study is built and validated using outdoor test data. On the basis of this model, influences of main structural design parameters including the installation angle and the orientation of the PV/T collector/evaporator are discussed and main parameters are optimized to further improve system operation performance. Based on optimal design parameters, economic feasibility of the proposed system under different weather conditions is analyzed using the life cycle cost (LCC) method. The system is integrated with solar PV/T, loop heat pipe and solar assisted air source heat pump technologies. This combined approach is benefit for improving solar energy comprehensive application efficiency of conventional solar PV/T systems. Moreover, it enlarges the application region of traditional air source heat pump water heating systems. Depending on different solar radiation conditions, this system can operate in different modes including solar photovoltaic LHP mode, solar assisted air source heat pump mode and the only air source heat pump mode. In this study, Beijing, Shanghai and Guangzhou were selected as typical representative cities in cold area, hot summer and cold winter area, hot summer and warm winter area. Typical meteorological year (TMY) data of three cities were extracted from TRNSYS. Based on TMY data, annual operation performance of the proposed system is calculated through the validated dynamic mathematic model. Firstly, PV/T collector/evaporators of three systems are all fixed in the south direction and the same installation angle (35°) was chosen. In this case, annual net power consumptions and solar heating fractions of three systems are calculated and compared. Then installation angles and orientations are optimized to ensure maximum solar energy application. The investigation results show that, among three cities, the solar heating fraction in Guangzhou is the largest. And the least electricity is consumed in Guangzhou, which is decreased by 43.9% and 44.7% respectively compared with those in Beijing and Shanghai. The comprehensive photothermal efficiency in Guangzhou is 8.19%, 5.58% higher than those in Beijing and Shanghai. Therefore, from the view of solar energy comprehensive efficient utilization, the application of the system is most proposed in Guangzhou, and then followed by Shanghai and Beijing. Considering impacts of installation angles and orientations, the ideal installation inclination of the system in Beijing, Shanghai and Guangzhou are 35°, 25°, and 35°, and the optimal installation directions of Beijing and Shanghai are facing the south, while that of Guangzhou is 30°east to the south. With the optimal parameters, it is found that solar heating fractions in Beijing and Guangzhou (i.e. 57.42% and 58.45%) are slightly higher than that in Shanghai. It is concluded that influences of two structural parameters are different for such system in different climatic areas. To ensure maximal solar energy application, it was necessary to optimize these two parameters. For the life cycle cost analysis, a traditional air source heat pump hot water heating system is chosen as the base system. The analysis results indicate that the initial investment of the system increases significantly, which is 2.5 times of that of the base system. However, the annual power consumption of the system is about half of that of the traditional system. Besides, solar power supply fractions in Beijing, Shanghai and Guangzhou are 53%, 51% and 66% respectively. As a result, the total operation and maintenance fees in the life cycle drop significantly, which are reduced by 67.86%, 59.00%, and 62.21% in Beijing, Shanghai and Guangzhou. The life cycle cost is correspondingly reduced by 58.75%, 49.83% and 53.09% in three cities. In conclusion, the application of this system is feasible for considered weather conditions in terms of both the operating performance and economic benefits. [ABSTRACT FROM AUTHOR]

Systematic understanding and classification of the spatial form of rural settlements is an important basis for rural renovation and scientific implementation of the strategy of Rural Revitalization at the present stage. In this paper, Pinggu district of Beijing is taken as the research area. According to the idea that rural residential areas are regarded as map patches, land use patterns and carriers, the identification indicators of rural residential types are constructed from three dimensions of intensity, structure and function. The intensity suitability, structure rationality and function coordination of each research unit are obtained by using multifactor comprehensive evaluation method. With the help of ArcGIS and GeoDa, the intensity suitability, structure rationality and function coordination degree of each research unit are obtained. A spatial correlation analysis of the three is carried out, and eight coupling types of rural settlements are classified based on three-dimensional characteristics. It is concluded that: (1) There is a positive spatial correlation among intensity suitability, structural rationality and functional coordination in Pinggu district, i.e. there is a spatial agglomeration characteristic, and the spatial distribution of hotspot analysis of suitability, rationality and coordination degree presents progressive, circle and mosaic patterns respectively. (2) There are significant differences in spatial and regional characteristics in Pinggu district, Beijing, with 62.8% of the villages not suitable for intensity, 51.3% of the villages are unreasonable in structure and 61.4% of the villages are inconsistent in function. (3) The main types of rural settlements in the whole district are unsuitable- reasonable- uncoordinated and unsuitable- unreasonable- uncoordinated, which account for 53.6% of the total rural settlements. Unsuitable- reasonable- uncoordinated rural settlements are mainly distributed in townships close to urban areas and unsuitableunreasonable- uncoordinated rural settlements are mainly located in the northern, southwestern and eastern hilly areas far from the urban area. [ABSTRACT FROM AUTHOR]

Efficient and timely acquisition of height and biomass of plant is important in improving agricultural management. The purpose of this paper is to investigate the feasibility of using UAV remote sensing to obtain these data. We took winter wheat as an example and conducted a field experiment between April and June 2015 at the Xiaotangshan National Precision Agricultural Research Demonstration Base in Beijing. UAV imageries were taken by a drone from the field at jointing, flagging and flowering stage, respectively. We then developed a crop surface model (CSM) based on these imageries to calculate the plant height and compared the results with field measurements. The image indices extracted from the UAV imageries were used to calculate the biomass using a stepwise regression (SWR) model at each of the three growing stages, as well as the average over the three growing stages. We also compared SWR with the partial least square (PLSR) method and the random forest (RF) method. The results showed that the plant height estimated from the crop surface model agreed well with the measurements with R²=0.87, RMSE=6.45 cm and NRMSE=11.48%. The biomass model was calibrated separately for the jointing, flagging and flowering stage separately, as well as for integrating the three stages as one. Comparison with the measured biomass showed that R², RMSE and NRMSE of the SWR model were 0.537 4, 0.0500 kg/m² and 19.13% at the jointing stage, 0.606 6, 0.092 0 kg/m² and 18.11% at the flagging stage, and 0.6324, 0.117 8 kg/m² and 14.91% at the flowing stage, respectively. For average biomass over the three stages, R², RMSE and NRMSE of the SWR model were 0.721 2, 0.137 2 kg · m-2 and 26.25% respectively. It was found that incorporating the plant height into the SWR model improved the biomass estimation, with its associated R² and NRMSE increasing to 0.794 1 and 22.56% while RMSE reducing to 0.117 9 kg/m². The SWR model is superior to the PLSR and RF model whose R² was 0.677 4 and 0.657 10, respectively. In summary, we presented methods to estimate the height and biomass of plant based on UAV imagery and validated it against field experiment with winter wheat as the model plant. [ABSTRACT FROM AUTHOR]

As the city is developing continuously recently, frequently occurred haze has increasingly raised residents’ concerns about the urban ecological problems. Motor vehicle exhaust gas is one of the major sources of atmospheric particulates. The road green system, an important ecological measurement, which plays a significant role in preventing the motor vehicle exhaust gas diffusion, is of great significance to improve urban air quality and residents’ life quality and the living environment. For the purpose of urban road greening plan, we used high resolution remote sensing images and street views to compile the road information tables so as to select six roads (Baiziwan Road, Linda North Road, Jiaodaokou East Avenue, Dongzhimen North Street, and Nongzhanguan South Road) in Beijing city as the sample set which represent different road green systems, green configurations and street aspect ratios. For the simulation experiment in this paper, we used three-dimensional microclimate software ENVI-met, which was based on fluid and thermodynamics (the calculation of the basic law of the fluid dynamics model), to simulate the interaction processes among ground, vegetation, building and atmosphere in a small-scale urban space. We constructed three-dimensional main model area and set main characteristic parameters of the sample places, such as building, greening and underlying surface structure, and achieved the numerical simulation of interactions among ground, vegetation, building and atmosphere by using the weather prediction subprogram to analyze governing equation. We conducted field experiment in order to compare it with the numerical simulation results. The monitoring points were set on the roadside and behind the tree respectively. Each experiment street was set with one monitoring section which has two monitoring points at the height of 1.5 meters. We selected PM10 as the monitoring item and measure meteorological factors such as wind speed, wind direction and temperature at the same time. We set the results of the non-vegetation particulate matter as background value and superposed it with the diffusion of that under different green configurations to analyze the law of particulate matter diffusion of different green configurations. The simulation results showed that, under the same condition of wind speed and wind direction, the changes of PM10 concentration on the leeward side of monitoring point were higher than that on its windward side, which proved that the motion of airflow caused the particulate matter accumulation on the leeward side and the spreading of particulate matter over the road as air flow rising, so the concentration of particles on the leeward side was the largest, and then gradually decreased as the building height increasing. Under the same condition of aspect ratio, the effect of arbor--shrub-grass configuration on reducing PM10 concentration was the most obvious, followed by the arbor--shrub configuration. The effect of arbor on reducing PM10 concentration was weak and the effect of shrub on that was the weakest. Under the same condition of green configurations, the smaller the street’s aspect ratio (the wider the street) was, the greater decrease in the concentration of PM10, which indicated that the wider street was favorable for ventilation and had the lower the concentration of pollutants and vice versa. Comparing the measured data with the numerical simulation data, the coefficient between the measured value and the simulated value was 0.9894, and the correlation between the simulated results and the field observation results was pretty high, so it could be proved that the convection-diffusion model that ENVI-met used was available for simulating the diffusion of atmosphere particulate matter and can give reasonable calculation results of the law of the diffusion of atmosphere particles. [ABSTRACT FROM AUTHOR]

The middle route of south-to-north water transfer project is a canal system. The downstream part from Anyang to Beijing has ice in winter every year. And the water resources requirement of this part is still hard in winter. . Ice condition is important to operation the canal system in winter. Ice evolution simulation is an important method to improve ice hazard threat of the middle route of south-to-north water transfer project by ice prediction and canal system automation operation. In this paper, a one dimensional operation simulation model for the middle route of South-to-North water transfer project has been established, which including unsteady flow simulation, water temperature simulation, ice cover evolution simulation and PI controller. It could describe the ice evolution process, hydraulic responses and gates operation process. And the model had taken the canal system characteristics into consideration including ice cannot flow through downstream gate of each pool and coupling of system hydraulic response. Ice observation is a dangerous work, and the project is so long. So, just limited ice observed data at some canal pools of the project is used to confirm the parameters value for the model. The parameters calibration results showed that the heat exchange coefficient of open channel hwi was 18 W/(m2·°C) and heat exchange coefficient under ice sheet conditions hwai was 26 W/(m2·°C), and the averaged error Ec of ice cover thickness and water temperature were 0.67 cm and 0.07 °C respectively. So the reliability of the model was confirmed to calibrate water temperature process, ice cover formation process and ice cover thickness process. And then, the model was applied to Beijing-Shijiazhuang part of the south-to-north water transfer project case simulation to study the ice situation evolution, hydraulic response and gate group regulation process in Ianuary-February 2016. The simulated canal system consists of 13 channels separated by 14 control gates. Water transfer flow of Hebei terminal and Tianjin were set as 20 m3/s and 10 m3/s. Two working conditions were simulated according to the temperature conditions. The results showed that the ice evolution parameters value can worked well to simulate ice evolution for long distance canal system, but the air temperature input conditions of the model must be the local value near each pool. The applied case results show that the canal system hydraulic response processes are complicated caused by ice evolution process, and the PI controller can reduce water level fluctuant amplitude and keep on the downstream water level operation mode well. The prediction of ice evolution process and gates operation processes was helpful to improve safety and economic benefit of the engineering. [ABSTRACT FROM AUTHOR]

Submerged combustion technology is a novel technology for natural gas pipeline heating. The core of the technology lies in the design of the heat exchanger. The design method of submerged combustion heat exchanger is introduced in this paper. The 200 kW submerged combustion heat exchanger is designed and put into use during the heating period of a gate station in Beijing. The measured data were used to calculate heat transfer coefficient of the convection inside and outside the tube, and the actual comprehensive heat transfer coefficient under rated design conditions was obtained through data fitting calculation, and then the comprehensive heat transfer coefficient of the design was modified. The calculation results showed that the modified comprehensive heat transfer coefficient of the design was 1. 56. Through actual heat transfer coefficient of convection outside tube calculated by maximum velocity of water bath outside the tube, fitting for the relation between the power and the maximum velocity of water bath, using of heating equipment in the 120 kW and stable operation of the measured data validation, water bath maximum velocity calculation error rate is 6.67%. This method can provide a reference for the same type of submerged combustion heat exchanger design. [ABSTRACT FROM AUTHOR]

We establish a Rosen-Roback spatial equilibrium model which decomposes the total economic growth into the change of labor input, total factor productivity (TFP) and wage differences. We calculate the model-based contribution of the cities, especially megacities, to Chinese aggregate economy. By using data of 285 cities from 2002 to 2015, we find out that the model-based contribution of Shanghai, Shenzhen, Beijing and Guangzhou to aggregate growth turn out to be higher than what is simply inferred from the share in GDP. Factor decomposition shows that the positive impact of megacities on Chinese economy comes from the increase in TFP and the increase in labor input, while the megacities widen wage dispersion of the whole country, generating a negative effect on economic growth. "Counterfactual" studies show that for the period 2002-2015, the top-five megacities increase the Chinese aggregate economy by 25.33%, and if the top-five did not enlarge the wage dispersion, then the aggregate economy would increase by 40.42%. Our research also shows that the overall development of the Yangtze River Delta and the Pearl River Delta regions is more balanced, while the Beijing-Tianjin-Hebei region still have a long way to go to reach the coordinated development. Since no previous study has used city level data in China to analyze the impact of megacities on Chinese economy, our research will fill this gap. According to the empirical results, this paper puts forward two suggestions, one is to further reduce the wage dispersion in China, the second is to further coordinate the Beijing-Tianjin-Hebei region for more balanced development. [ABSTRACT FROM AUTHOR]

The evaluation of arable land quality is one of the important means to protect and manage arable land. In order to meet the needs of current arable land management work and protect the safety of national arable land resources, it is necessary to establish an arable land quality index system to evaluate the arable land quality. Based on the change of human demand for arable land resources, the components of arable land use system and the relationship between various components of arable land use system, this paper systematically expounded the theoretical framework of arable land quality evaluation，and the evaluation index system of arable land quality was established by the matching of different demand hierarchy characteristics of human and supply of arable land resources. The evaluation index system of arable land quality consisted of five dimensions: geology characteristics, soil traits, farming conditions, health status of arable land and biological characteristics of arable land. According to the different characteristics of each dimension of arable land quality, suitable evaluation methods were selected. The three dimensions of geology characteristics, soil traits and farming conditions were calculated by using the weighted additive. The health status of arable land is calculated by the “1+X” cumulative model; the biological characteristics of arable land were calculated by coefficients. Then, the quality of arable land for high yield and high efficiency demand was evaluated by the method of additive, and the quality of arable land for green health and sustainable development was evaluated by the method of revised. The quality of arable land in Daxing District of Beijing was evaluated by using multi-source and multi-scale data. The results showed that the evaluation results of arable land quality in Daxing District were divided into five grades at equal intervals of 20 points. The arable land quality index [80,100] was excellent, [60, 80) was good, [40, 60) was medium, [20, 40) was lower, and [0, 20) was poor. Under the conditions of high yield and high efficiency, the excellent area accounted for 88.27% of the total arable land, the good accounted for 11.73%. Under the condition of green health demand, the excellent accounted for 73.61% of the total arable land, and the good accounted for 26.39%. Under the conditions of sustainable development demand, the excellent accounted for 3.03% of the total arable land, and the good accounted for 52.30%, medium accounted for 40.39%, and lower accounted for 4.27%. From the perspective of space, the results of arable land quality evaluation of high yield, high efficiency, green health and sustainable development demand were all high in the east and low in the west. By comparing the results of arable land quality evaluation under different demand conditions, the area of arable land in excellent is decreasing, while the area of arable land in good, medium and lower is increasing. The health status of arable land and the biological characteristics of arable land have become important factors affecting the quality improvement of arable land. Research conclusions are that the evaluation index system of arable land quality based on sustainable development demand can provide effective support for the evaluation and management of arable land, and is more in line with the national quantity, quality and ecological management needs of arable land. [ABSTRACT FROM AUTHOR]

Energy feedstuffs, the most important and indispensable components in the pelleted complete feeds, provide energy in the form of soluble carbohydrate, oil and fat. Energy feedstuffs mainly includes cereals, cereal brans, molasses, oil, tuber and tuberous root, among which corn, wheat, barley, sorghum, wheat/rice bran, pelleted cassava residue and beet pulp are widely utilized in diets for livestock and poultry. Knowledge of the thermal properties of different feedstuffs is required for designing and parameter optimization of thermal process such as conditioning and pelleting processing, especially when energy costs, pellet quality and uniformity are the main consideration. The specific heat, thermal conductivity and thermal diffusivity are the most important thermal properties. In this paper, eight energy feed ingredients (4 cereal grains: corn, wheat, barley, sorghum; 4 processed by-products: wheat bran, pelleted cassava residue, pelleted beet pulp, rice bran) were obtained from a feed mill in the suburb of Beijing, and ground in a mini-mill equipped with screens having a aperture size of 1.5, 2.0 or 2.5 mm to obtain feed meals with three particle sizes (except rice bran, which could pass through the 1.5 mm screen completely without being ground). The moisture content of all feed meal samples was conditioned to 12% wet basis in order to eliminate the effect of moisture content difference on thermal properties. The specific heat, thermal conductivity of feed meals at the temperature range of 25-100 °C were determined by DSC (differential scanning calorimetry) and KD2 Pro (thermal properties analyzer), respectively. Thermal diffusivity of feed meals was calculated using measured thermal conductivity, specific heat, and bulk density. Based on the experimental data, prediction models of three thermal properties as a function of temperature were established. The effects of particle size on thermal properties of feedstuffs were analyzed. The particle size of eight feedstuffs grinding through screens with aperture size of 1.5, 2.0 and 2.5 mm ranged from 257.61 to 511.79 μm, 325.65 to 594.83 μm and 335.28 to 671.05 μm, respectively, which increased significantly with the increase in mesh size. There were significant differences between the values of particle size of 8 feedstuffs through the same mesh size. The values of specific heat of 4 grain meals (passing a screen with aperture size of 1.5 mm) increased with temperature (25-100 °C) and ranged from 1.678 to 2.421, 1.644 to 2.402, 1.642 to 2.385, and 1.649 to 2.441 kJ/(kg·K), respectively. For wheat bran, cassava residue and beet pulp, the values were found to range from 1.621 to 2.540, 1.580 to 2.195, 1.746 to 2.351 kJ/(kg·K). The specific heat of rice bran raised from 1.966 kJ/(kg·K) at 25 °C to 1.985 kJ/(kg·K) at peak temperature (28.0 °C), then declined to 1.868 kJ/(kg·K) at end-set temperature (33.5 °C), and finally increased to 2.671 kJ/(kg·K) at 100 °C. There was no significant effect of particle size on the specific heat of all feedstuffs (P>0.05). The specific heat followed linear relationships with temperature at the range of 25-100 °C for 4 grains, and cubic polynomial relationships for wheat bran, cassava residue and rice bran, and a second order polynomial relationship for beet pulp. The values of thermal conductivity of 4 grain meals (passing a 1.5 mm screen) increased nonlinearly with temperature (25-100 °C) and varied from 0.089 to 0.299, 0.078 to 0.336, 0.088 to 0.276 and 0.082 to 0.288 W/(m·K), respectively. For 4 processed by-products, the thermal conductivity was found to raise from 0.054 to 0.190, 0.092 to 0.362, 0.085 to 0.263, and 0.064 to 0.202 W/(m·K), respectively. Significant differences were observed between the thermal conductivity of 8 feed mills (passing a 1.5 mm screen) at a higher temperature (85 or 100 °C), and the thermal conductivity of cassava residue was the highest, followed by wheat, wheat bran with the lowest value. For the same feedstuffs, the thermal conductivity of feed mills, at the same temperature, decreased generally with the increase in particle size, and the higher temperature, the stronger decrease. Cubic polynomial relationships of thermal conductivity with temperature (25-100 °C) were established for 4 grains and beet pulp with different particle sizes, and quadratic polynomial relationships were obtained for wheat bran, cassava residue and rice bran. The values of thermal diffusivity of 4 grain meals (passing a 1.5 mm screen) varied from 7.459×10-8 to 17.320×10-8, 6.694×10-8 to 19.195×10-8, 7.878×10-8 to 17.045×10-8, and 6.857×10-8 to 16.109 ×10-8 m2/s at temperature range of 25-100 °C, respectively. The values was observed to ascend from 9.543×10-8 to 20.892×10-8, 8.217×10-8 to 23.254×10-8, 7.258×10-8 to 16.646×10-8 and 8.092×10-8 to 18.718 ×10-8 m2/s for 4 processed by-products, respectively. In general, the thermal diffusivity of the 8 energy feedstuffs had a slow increase with temperature at the range of 25-55 °C, and a sharply raise with temperature at the range of 55-100 °C. The thermal diffusivity of all 8 feedstuffs tended to decline with increasing particle size. The thermal diffusivity displayed second order polynomial relationship with temperature at the range of 25-100 °C for wheat bran and rice bran, and cubic polynomial relationships for the other 6 feedstuffs. [ABSTRACT FROM AUTHOR]

Method of train traction calculation is applied into calculate station-end turn-back capacity of urban rail transit, and the calculation effects are analyzed. First of all, this paper described and analyzed categories and operation progress of station-end turn-back, and obtained the minimal departure interval calculation formula of single track turn-back and double track turn-back, and suggested the reasonable turn-back track number when the throat area cannot operate parallel. Then, the kinetic equation, which solved the calculation method of station-end turn-back by using train traction calculation, was proposed. Finally, this paper used Beijing subway station Beijingxi under construction and DKZ4 trains as an example, and obtained the minimal departure intervals of station-end turn-back while DKZ4 train was operated under energy-saving mode and time-saving mode: the turn-back time using double tracks is much longer than that using single track. Based on these, this paper compared and analyzed the calculation results with that using average acceleration and deceleration, and shows that using train traction calculation is valuable in the capacity calculation of turn-back station. [ABSTRACT FROM AUTHOR]

In 1814, Li Huaiyuan, alias Li Yao, Ayao (Ayew), a linguist (tongshi) in Guangzhou, was arrested and thrown into jail by the Chinese authorities, apparently for his service to the British traders in bringing letters and presents to a senior minister in Beijing. The British made various attempts to rescue him, including suspending trade with the Chinese. Ayew was ultimately sent to exile to Xinjiang. The present paper examines this so-called "Ayew Incident" in the history of East India Company trade in China. It analyses the real causes for the arrest of Ayew and explains how and why the British would want to rescue him at the risk of great loss in revenue. It hopes to demonstrate the significant role and position played by the linguists in the Canton System and Sino-British relationship in the eighteenth and nineteenth centuries. [ABSTRACT FROM AUTHOR]

This paper studies the mode choice problem considering the peak travel chain in a day. The transportation system comprises a subway parallel to a bottleneck-constrained highway between a residential area and a working place. Commuters can get their destinations by either auto or transit only; besides these two modes, they can drive to .the bottleneck, park there and then take subway to the destination. Based on the bottleneck theory, a hierarchical Logit model is used to describe commuters' mode choice behaviors, and then mode choice equilibrium equations under elastic demand are constructed. Furthermore, optimal fare and parking fee strategies under four mechanisms are discussed. It is shown that when transit and park-and-ride place are operated by government and the working area parking lot belongs to a private enterprise, lower fares and higher parking fees in working area can effectively encourage parking interchanging, increase public transit trip contribution rate and maximize the system's total net benefit. Numerical results also support the current differentiation parking charge policy in Beijing. [ABSTRACT FROM AUTHOR]

The fact that local governments rely heavily on land finance has fostered the emergence of "land lease price champion" in many cities across the country through land auctions and land auctions are most likely to cause excessive land auction premium. This paper focuses on residential and commercial land lease transactions in Beijing for a period from 2003 to 2010 and studies the driving forces of the observed land auction premium using hedonic pricing methodology. Results show that land use purpose, floor-to-site ratio, location, the type of land bidder and distance to city center significantly impact the land auction premium. Comparing with private real estate companies, state-owned real estate firms exert more impact on land auction premium. Another finding is that part of the stimulus package released in 2009 to cope with the economic crisis has been directed to land market through state-owned real estate firms that pushes up the land prices. [ABSTRACT FROM AUTHOR]

This paper presents seismic retrofit for the single-story brick-wood structure representative of existing rural buildings in Beijing. The retrofitting effectiveness was examined through large-scale shaking table tests on the unretrofitted and retrofitted specimens. The test results indicate that, for the unretrofitted specimen, the front brick columns deform and damage severely when subjected to the longitudinal motions, because large of lateral stiffnesses difference exists between the front and back longitudinal walls. The brick gables experience significant out-of-plane deformation, resulting in diagonal cracks. The unretrofitted specimen is cracked under minor earthquakes, significantly damaged under design basis earthquakes, and approaches to collapse under rare earthquakes. The method of seismic retrofit was proposed based on the test results of the unretrofitted specimen, including the addition of a steel doorframe, steel window frames and steel plate collar beams, and the strengthening of the brick gables and columns by cement mortar reinforced with steel mesh. Shaking table test results show that the retrofit method significantly improves the earthquake-resistant capacity of the brick-wood building structure, and the retrofitted specimen can achieve the design objective of 'operational under minor earthquakes, repairable damage under design basis earthquakes, and collapse prevention under rare earthquakes'. [ABSTRACT FROM AUTHOR]

Based on the data of 606 questionnaires collected in 23 neighborhoods in Beijing in 2008, this paper analyzes the degree, motivation and implications of homeowners' political participation. First, urban homeowners tend to participate in the rights movements. Second, gender, occupation and the level of income have significant influence on homeowners' participation in these movements. Third, as an important part of Chinese middle class, Beijing homeowners tend to support the incumbent regime and to be in favor of the status quo. Most of them are in favor of the social order and economic growth. However, those who have a strong sense of "status inconsistency" and a strong sense of internal efficacy are more likely to participate in rights movements. [ABSTRACT FROM AUTHOR]

Since the early 1990s, urban neighborhoods have seen a rapid growth of protests by homeowners for their "rights." This paper tries to study the origin and development of the rights movements from the perspectives of political process and mobilization structure. Based on field work in several homeowners committees in Beijing, the author argues that the rapid changes of the social structure, mobilization structure and general discourse on the movements contribute to the increase of homeowners' rights movements. [ABSTRACT FROM AUTHOR]