المؤلفون: Zhan, Jinyan, Wang, Chao, Wang, Huihui, Zhang, Fan, Li, Zhihui

المصدر: Elsevier, Renewable and Sustainable Energy Reviews. 189(PB)

الوصف: Global climate change, rapid urbanization, and drastic economic development pose many threats and challenges to humanity, increasing the need for sustainable development, urban ecological management, and low-carbon transformations. Comprehensive simulation models rarely involve all the aspects of carbon emissions, carbon sequestration, population, economic, and energy sections. Firstly, this study evaluated the changes of the carbon neutrality rate in the Beijing-Tianjin-Hebei (BTH) region from 2000 to 2019. Then, a Carbon Neutrality Simulation Model (CNSM) was built using system dynamics. Finally, an optimal development scenario and pathways were identified for the BTH region based on scenario analysis. The results revealed that: (1) Carbon emissions first increased rapidly and then stabilized, carbon sequestration did not significantly change, and carbon neutrality rate decreased. (2) The baseline scenario (S1) did not reach the “dual carbon” target with carbon emissions increasing to 832.62 Mt in 2030 and 914.26 Mt in 2060, whereas the carbon neutrality rate increased to 17.96 % in 2030 and 22.69 % in 2060. (3) Among the single-factor scenarios (S2–S7), the industrial restructuring scenario (S3) had the greatest carbon reduction potential, reaching the carbon peak target. (4) Among the multi-factor scenarios, all the three baseline economic scenarios (S8–S10) reached carbon peak target in 2043, 2029, and 2022. The high constraint scenario (S10) reached the carbon neutrality target, as the optimal development scenario for the BTH region. All the results provide scientific evidences to achieve carbon neutrality target and regional sustainable development.

الإتاحة: https://ideas.repec.org/a/eee/rensus/v189y2024ipbs1364032123008134.html

المؤلفون: Li, Mingqiang, Li, Zhihui, Yip, Chi-Man (Winnie)

المصدر: Elsevier, Social Science & Medicine. 298(C)

الوصف: Informal payment for medical services is a common phenomenon in China. Patients make informal payments, in cash or in kind, to physicians in addition to official charges billed for medical services. This paper assesses the associations between patients' perceptions of the physician as an agent for the patient's interests (physician agency problem) and informal payment behavior. Using data of 24,000 and 6700 rural households respectively from the Health Development of Rural China Program database (collected in 2008) and Ningxia data source (collected in 2015), we find that patients' concern about physician agency problems is significantly associated with informal payments. The data shows that patients are more likely to make informal payments when they show low trust towards their physicians. For example, in the surgical cases, among patients who strongly distrusted the physicians, 17.9% (95% confidence interval [CI]:]: 13.5, 22.3) initiated informal payments, compared to 8.0% (95% CI: 5.1, 10.9) who expressed “strong trust” in their physicians. Poor communication was also significantly associated with an increase in the informal payment rate. For example, in the non-surgical setting, among the patients who rated the physicians' explaining skills as “poor,” 5.9% (95% CI: 5.0, 6.9) of them made informal payments, significantly higher than the patients who rated “excellent” (of whom 1.8% made informal payments 95% CI, 0.9, 2.7). In this study, we provide an explanation for this finding: patients may initiate informal payments to physicians in order to mitigate the physician agency problem. It suggests that to mitigate informal payments, improving alignment between doctors' incentives and patients' interests would be essential.

الإتاحة: https://ideas.repec.org/a/eee/socmed/v298y2022ics0277953622001599.html

المؤلفون: Zhan, Jinyan, Chu, Xi, Li, Zhihui, Jia, Siqi, Wang, Guofeng

المصدر: Elsevier, Technological Forecasting and Social Change. 144(C):401-411

الوصف: Land use/cover change (LUCC) in Northeastern China (NEC) has dynamically changed over the past several decades. However, few LUCC studies have examined the value of ecosystem services (VES) in major grain production areas involved in national food production. Measuring this process and incorporating VES into agricultural management can provide a scientific basis for environmental management and sustainable agricultural development. Thus, taking NEC as an example, based on modified value coefficients, we estimated changes in VES in response to LUCC over the past 25 years (1990–2015), and changed VES over this period were incorporated into agricultural management. We found that VES decreased by 27.24% and increased by 61.57% during the periods of 1990–2000 and 2000–2015, respectively. In addition, total VES increased by 17.55%. The decrease of VES during the period of 1990–2000 resulted from cultivated land reclamation, forest and wetland degradation. VES increase was influenced by land retirement and afforestation programs implemented in NEC. When changes in VES were incorporated into agricultural management, small farms appeared to be going down remarkably compared with those for mid-sized and large farms. Prudent agricultural management should be considered for mid-sized and large farms to ensure greater ES-related benefits to humans.

الإتاحة: https://ideas.repec.org/a/eee/tefoso/v144y2019icp401-411.html

المؤلفون: Du, Juan, Li, Yiwen, Li, Zhihui, Li, Jichao, Wang, Zinan, Zhang, Hongwu

المصدر: Elsevier, Energy. 172(C):618-629

الوصف: An industrial highly loaded gas compressor with the large turning angles in gas turbines always causes the serious flow separations, which leads to the significant increase in aerodynamic losses and the evident deterioration of the pressure rise ability. In order to solve this issue, a novel active flow control technique inspired by the Coanda effect is introduced in this study. Here, the Zierke & Deutsch airfoil with the camber angle of 65° is selected for the reference profile of the highly loaded compressor cascade. Design of Experiment (DOE) is firstly used to obtain the sensitivity information of the geometric parameters in building the Coanda jet flap. The cascade shape with the optimal aerodynamic performance is then figured out based on the optimization method. The comparison of the flow details between the optimization result and the prototype is performed to further understand the flow mechanisms behind the performance enhancement. Finally, the experimental measurements are conducted to validate the effectiveness of the well-designed Coanda jet flap in the wind tunnel. The numerical and experimental results show that the Coanda jet can effectively improve the aerodynamic performance of the highly loaded cascade. A tradeoff exists between the increased mixing losses near the slot and the decreased shearing effects near the trailing edge when the mass flow rate of the Coanda jet is increased. The total pressure losses can be reduced by up to 18.4% when the normalized mass flow rate of the jet flow is equal to 1%. Meanwhile, the static pressure rise coefficient can be increased by 8.8% when the mass flow rate of the Coanda jet is equal to 1.5%.

الإتاحة: https://ideas.repec.org/a/eee/energy/v172y2019icp618-629.html

المؤلفون: Li, Zhihui, Kim, Rockli, Subramanian, S.V.

المصدر: Elsevier, Social Science & Medicine. 277(C)

الوصف: To achieve Sustainable Development Goal targets related to child health and well-being, it is important to quantify inequalities in the essential child health interventions. We used the latest available Demographic and Health Surveys from 65 low-income and middle-income countries between 2005 and 2018. We examined economic-related inequalities in 15 essential child health interventions spanning across four domains: nutrition, behavioral health, household environment, and maternal factors. In the pooled analysis, we observed significant inequalities in all child health interventions, except in the use of oral rehydration therapy (ORT) for child diarrhea. The interventions with the largest adjusted difference between the richest (Q5) and the poorest (Q1) groups were in household environment domain: improved sanitation at 55.6 percentage points [PPs] (95% confidence interval [CI]: 54.7, 56.6), low indoor pollution at 43.5 PPs (95% CI: 41.4, 45.9), and safe stool disposal at 39.8 PPs (95% CI: 38.7, 41.0). In 35 countries, the adjusted difference between Q5 and Q1 groups in improved sanitation was found to be larger than 50 PPs. At the same time, country-specific analyses revealed substantial heterogeneity in the extent of inequalities in child health interventions. An inverted-U shape curve was identified between the mean intervention coverage rate and the magnitude of inequalities for household environmental and maternal interventions. This suggests an initial exacerbation of inequality in child health interventions as the coverage increases until it reaches an inflection point at which inequality begins to decline even as the coverage continues to improve. Our findings call for more systematic monitoring of economic-related inequalities in child health interventions to develop equity-oriented policies and programmes in global health.

الإتاحة: https://ideas.repec.org/a/eee/socmed/v277y2021ics0277953621001489.html

المؤلفون: Xia, Yingji, Sun, Zhe, Qu, Zhaowei, Liu, Tianze, Li, Zhihui, Gao, Yuhong

المصدر: Elsevier, Physica A: Statistical Mechanics and its Applications. 566(C)

الوصف: The tremendous growing ownership of electric bikes (e-bikes) brings serious traffic safety problems. Existing models aim to describe the conflict between pairwise traffic participants, which may not be appropriate for analyzing traffic conflicts among multiple e-bikes. This study aimed to model the trajectory changes for e-bikes in conflict scenarios, and simulate the e-bike movements during conflicts. First, the conflict zone of e-bike is represented as an isosceles triangle, within which the e-bikes would either adapt a lateral (right or left) shift in its trajectory or slow down to avoid potential collisions. Second, the kinematic principles of the classical optimal velocity model were employed to solve the overlapping problem of the cyclist reactions to the multiple conflictive e-bikes. Finally, the model was calibrated with trajectory data collected from video surveillance, and two types of numerical simulations were carried out. The experiment results verified the model performance of simulating the conflictive e-bike trajectories with multiple e-bike involved conflicts. It is also found that the unique typical phenomena of e-bikes such as the diagonal spatial distributions can be reproduced. It is hoped that the findings of this study may be helpful in modeling and simulation study of e-bike flow.

الإتاحة: https://ideas.repec.org/a/eee/phsmap/v566y2021ics0378437120309559.html

المؤلفون: Li, Zhihui, Deng, Xiangzheng, Peng, Lu

المصدر: Elsevier, Technological Forecasting and Social Change. 158(C)

الوصف: To clarify trajectories and impact factors for CO2 emissions is critical to emissions reduction, especially at finer sectoral and spatial resolutions. We statistically disaggregated city-level sectoral CO2 emissions to districts of Beijing during 2004–2013 and examined the impact factors using an extended STIRPAT model. Results revealed that CO2 emissions decreased in manufacturing sector, while increased in residential and transportation sectors, which were promising fields for emissions reduction. Spatial dynamics of district-level CO2 emissions indicated that industrial carbon reduction should focus on not only core urban area but also the new merged hotspot districts. The impact estimations indicating by elastic coefficients revealed that population size (0.6, 0.49, 1.06), GDP per capita (0.63, 0.56, 0.8), energy intensity (0.93, 0.86, 0.96) and secondary industrialization level (0.36, 0.8, 0.88) can lead to increase in total, industrial and transportation CO2 emissions, while urban land area size (−0.47, −0.24, −0.81) exerted negative effects on them. In addition, private vehicle ownership (0.45) positively affect transportation CO2 emissions. Residential CO2 emissions were positively influenced by urban land area size (0.44), urbanization level (0.18), population density (0.49) and private vehicle ownership (0.11). Given these findings, policy recommendations for CO2 emissions reduction and mitigation were suggested for low-carbon urban development.

الإتاحة: https://ideas.repec.org/a/eee/tefoso/v158y2020ics0040162520309501.html

المؤلفون: Liu, Wei, Zhan, Jinyan, Zhao, Fen, Wang, Pei, Li, Zhihui, Teng, Yanmin

المصدر: Elsevier, Technological Forecasting and Social Change. 137(C):1-9

الوصف: Against the background of new urbanization, urban agglomeration plays an important role in boosting development in surrounding areas. It is important that energy consumption is reduced and energy productivity improved. The Pearl River Delta Metropolitan Region (PRD) is one of the most promising city agglomerations in China. Therefore, based on data sourced from China City Statistical Yearbooks (2006–2016) and Guangdong Statistical Yearbooks (2006–2016), a global Malmquist–Luenberger productivity index is adopted to analyze the change trends of energy productivity growth in the PRD during 2005–2015. The estimation results show that there are differences among the change trends of energy productivity growth in the nine cities in the PRD, and that productivity growth improved during the study period. The greatest contributor to energy productivity growth is technological progress. We also identified the key determinants affecting energy productivity growth using generralized least squares regression and found that industrial structure, openness index and capital per capita have a positive effect. The energy price, energy intensity, per capita of GDP, R&D intensity and government regulation have a negative effect on energy productivity growth. These conclusions inform decision makers in improving energy productivity and coordinating economic development and environmental protection in the PRD.

الإتاحة: https://ideas.repec.org/a/eee/tefoso/v137y2018icp1-9.html

المؤلفون: Li, Zhihui, Liu, Yanming

المصدر: Elsevier, Energy. 126(C):217-230

الوصف: This paper concentrates on the application of blade-end treatment to axial compressors by means of the optimization algorithm. The blade-end treatment reduces the end wall losses and extends the stable margin by modifying blade shape near the end wall region. It contains three types of passive flow control measures, i.e., the end-bend, end-dihedral and end-sweep treatment. Firstly, the effects of blade-end treatment were reviewed based on the open literature published over the past 30 years. All of these effects essentially influence the compressor performance by changing the blading loading distributions in the streamwise or spanwise directions. There is a trade-off between the improved end wall flows and the deteriorated mid-span flows. It’s difficult to quantitatively apply these measures to achieve an optimal balance according to the traditional engineering experience. Optimization algorithm provides an efficient access to resolve this issue by automatically obtaining the utmost benefit. Secondly, an optimization example of NASA Stage 35 was conducted to validate against the summarized flow mechanisms. The optimal geometry parameters of cantilever stator vane near the end wall region were obtained by employing a surrogate model in conjunction with a genetic algorithm for optimization. Finally, optimization results indicated that the optimal vane blade featured an obvious combination of forward end-sweep, positive end-dihedral and end-bend. The stator total pressure losses were reduced with the blade-end treatment based on optimization method. A significant reduction of loss occurred near the shroud region, from the 80% span to the casing, while the performance was degraded within the mid-span region, approximately 50%–80% span. The resulting mechanisms are consistent with the knowledge obtained from the literature review and this will provide meaningful guidance on the further compressor design process.

الإتاحة: https://ideas.repec.org/a/eee/energy/v126y2017icp217-230.html

المؤلفون: Li, Zhihui, Deng, Xiangzheng, Yin, Fang, Yang, Cuiyuan

المصدر: ZBW - Leibniz Information Centre for Economics, EconStor Open Access Articles and Book Chapters. :1-11

الوصف: Land degradation is a complex process which involves both the natural ecosystem and the socioeconomic system, among which climate and land use changes are the two predominant driving factors. To comprehensively and quantitatively analyze the land degradation process, this paper employed the Normalized Difference Vegetation Index (NDVI) as a proxy to assess land degradation and further applied the binary panel logit regression model to analyze the impacts of the driving factors on land degradation in the North China Plain. The results revealed that an increase in rainfall and temperature would significantly and positively contribute to the land improvement, and conversion from cultivated land to grassland and forest land showed positive relationship with land improvement, while conversion to built-up area will lead to land degradation. Besides, human agricultural intensification represented by fertilizer utilization will help to improve the land quality. The economic development may exert positive impacts on land quality to alleviate land degradation, although the rural economic development and agricultural production will exert negative impacts on the land and lead to land degradation. Infrastructure construction would modify the land surface and further resulted in land degradation. The findings of the research will provide scientific information for sustainable land management.

الإتاحة: https://ideas.repec.org/a/zbw/espost/171303.html