Research Object Research Articles

Bacteria-Like Gaiella Accelerate Soil Carbon Loss by Decomposing Organic Matter of Grazing Soils in Alpine Meadows on the Qinghai–Tibet Plateau

The alpine meadows of the Qinghai–Tibet Plateau have significant potential for storing soil carbon, which is important to global carbon sequestration. Grazing is a major threat to its potential for carbon sequestration. However, grazing poses a major threat to this potential by speeding up the breakdown of organic matter in the soil and releasing carbon, which may further lead to positive carbon-climate change feedback and threaten ecological security. Therefore, in order to accurately explore the driving mechanism and regulatory factors of soil organic matter decomposition in grazing alpine meadows on the Qinghai–Tibet Plateau, we took the grazing sample plots of typical alpine meadows as the research object and set up grazing intensities of different life cycles, aiming to explore the relationship and main regulatory factors of grazing on soil organic matter decomposition and soil microorganisms. The results show the following: (1) soil microorganisms, especially Acidobacteria and Acidobacteria, drove the decomposition of organic matter in the soil, thereby accelerating the release of soil carbon, which was not conducive to soil carbon sequestration in grassland; (2) the grazing triggering effect formed a positive feedback with soil microbial carbon release, accelerating the decomposition of organic matter and soil carbon loss; and (3) the grazing ban and light grazing were more conducive to slowing down soil organic matter decomposition and increasing soil carbon sequestration.

Stability Analysis Method of a Hierarchical Control Structure Microgrid Based on a Small-Signal Model and Hopf Bifurcation Theory

To the oscillation and stability problem caused by multi-scale and broadband electromagnetic dynamics among many isomerized power electronic devices in a microgrid, a small-signal model of hierarchical control structure microgrid and stability analysis method based on oscillation trajectories are proposed. Moreover, a hierarchical control structure is used as the research object in microgrid, and the analysis is performed based on the small-signal model and Hopf bifurcation theory. First, the small-signal model of the hierarchical control structure microgrid is established, combining the dominant eigenvalue and participation factor analysis methods, to analyze the influence of the controller and related sensitive parameters on the dynamic performance of the system. Then, based on the small-signal model and Hopf bifurcation theory, a stability analysis method based on oscillation trajectories is proposed. The relationship between different oscillation modes and limit cycles in the microgrid system and the influence of the sag control parameter values on the oscillation trajectory and stability domain of the system are researched on. Combining Hopf bifurcation theory and oscillation trajectory to delineate the stable domain of parameter trajectories, the influence of secondary control on the system stability is analyzed under different oscillation trajectories and load disturbances, revealing the corresponding relationship between the state trajectories of different oscillation modes and system stability of a hierarchical control structure microgrid. Based on the proposed oscillating trajectories, the stability analysis method has sufficient universality for studying the impact of system stability, establishing the parameter selection standards for the design of microgrids. Finally, according to the verification results, the correctness and applicability of above methods are verified.

Study on the Structural Characteristics of Mesh Filter Cake in Drip Irrigation: Based on the Growth Stage of Filter Cake

Mesh filters are frequently employed in water-saving irrigation fields. Studies addressing the method of cake formation and the characteristics of the cake during the mesh filter’s growing phase are still missing. One-way and orthogonal experiments were carried out using mesh filters with 220 μm and 320 μm aperture sizes as the research objects, taking particle concentrations, inlet flow, and growth phases as experimental factors. According to the variation rule of seed pressure drop in the formation process of filter cake, the growth process of filter cake is divided into four stages, which are as follows: slow blockage first and second stages (M1, M2), fast blockage stage (M3), and filter cake filtration stage (M4). Moreover, the size distribution, porosity (ε), pore-to-particle ratio (KP), and median size (d50) of the filter cake were used to represent the structural characteristics. The results show that the growth of filter cake was a process that started with the filling of mesh pores by intercepted particles and progressed to the filling of large-particle skeleton pores by subsequently filtered particles. During this process, the proportion of intercepted particles gradually decreased, while the proportion of filtered particles increased incrementally, and the median size (d50) and porosity (ε) decreased. Meanwhile, the smaller the aperture size of the screen, the smaller the filter cake’s median size (d50) was, but the larger the pore-to-particle ratio (KP) was. As the flow rate increased, the porosity (ε) was augmented in the M1 and M2 stages; however, it decreased in the M3 and M4 stages. The concentration had a minor influence on the filter cake’s porosity. Lastly, the regression model for filter cake porosity under two aperture size conditions was established, based on factors such as flow rate, concentration, and growth stage. The coefficients of determination, R2, for the model were 90.33% and 80.73%, indicating a good fit.

Investigation on the thermal runaway mechanism of electrolyte in lithium-ion batteries via ReaxFF molecular dynamics

Lithium-ion batteries have the advantages of high energy density and high cycle times, and have been widely used in portable electronic devices, electric vehicles, and large-scale energy storage. However, lithium-ion batteries are prone to thermal runaway. Subsequently, electrolyte decomposition and combustion occur, leading to an increase in battery temperature and even causing fires or explosions. In order to explore the reaction mechanism of thermal runaway in lithium-ion battery electrolytes, the volatile and combustible organic solvents are selected as the research object. Three different organic solvents were established, namely pure ethylene carbonate (C3H4O3) solvent and its mixture with dimethyl carbonate (C3H6O3) and diethyl carbonate (C5H10O3), respectively. The effect of heating on the thermal runaway of organic solvents was studied using reactive force field molecular dynamics (ReaxFF MD). All three organic solvents will produce a large amount of CH2 free groups and flammable organic substances such as C2H4 during pyrolysis, which is the main reason for thermal runaway of lithium-ion batteries. The research results may contribute to preventing and suppressing thermal runaway in lithium-ion batteries.

Inspection supervision and corporate green total factor productivity

This study takes the state-owned listed companies in China's capital market as the research object and empirically tests the relation between inspection supervision and corporate green total factor productivity (GTFP). Research results indicate that inspection supervision can considerably improve enterprise GTFP. Heterogeneity analysis results show that the promotion effect of inspection supervision on corporate GTFP is primarily concentrated within large-scale enterprises and those with better institutional environments. The findings offer guidance for governmental policies and strategies to enhance and sustain inspection supervision practices.

Study on the Hydration Heat Effect and Pipe Cooling System of a Mass Concrete Pile Cap

Under the action of cement hydration heat, the construction environment, thermal insulation measures, and pipe cooling systems, a mass concrete pile cap is subject to a complex internal temperature field, which makes it difficult to control its internal surface temperature difference (TISTD), the internal adiabatic temperature rise (TIATR), and the surface temperature (TST). In this study, a mass concrete pile cap of a very large bridge (the length, width, and height were 26.40 m, 20.90 m, and 5.00 m, respectively, and the central-pier pile cap was constructed with C40 concrete) was taken as the research object. The control factors affecting the temperature field of the pile cap were determined by comparing the field temperature measurements with the values calculated with finite element software simulation analysis. By using Midas Civil (2022 v1.2) and Midas FEA (NX 2022) finite element software, these factors (the concrete mold temperature, the concrete surface convection coefficient, the ambient temperature, the pipe cooling system parameters, etc.) were numerically analyzed, and their influence laws and degrees were determined.

Numerical Simulation Study of Wall Thickness Change Rule of Single Point Progressive Molding of Al5083

With the development and progress of science and technology, the application of single-point progressive molding is more and more extensive, but single-point progressive molding still exists the problem of excessive thinning of wall thickness of molded parts, which seriously affects the quality of molded parts. The article takes Al5083 plate forming cone as the research object, uses Abaqus finite element simulation software, according to the principle of single variable, respectively explores the influence of process parameters such as tool head diameter, layer spacing, feed rate and residual height on the average wall thickness reduction rate and the maximum wall thickness reduction rate of the molded parts. The results show that: increasing the tool head diameter, the average wall thickness reduction rate increases and the maximum wall thickness reduction rate decreases; the average wall thickness reduction rate and the maximum wall thickness reduction rate increase with the increase of ply spacing; the average wall thickness reduction rate and the maximum wall thickness reduction rate increase with the increase of the tool feed rate; the average wall thickness reduction rate decreases and the maximum wall thickness reduction rate increases with the increase of the residual height.

The Incidence and Influencing Factors of Sleep Disorders in Cyber Knife Patients during Treatment

Objective: This study first analyzes the incidence and influencing factors of sleep disorders in Cyber Knife patients during treatment, in order to provide more accurate strategies for clinical prevention, early diagnosis, and treatment. Methods: A total of 101 patients who underwent Cyber Knife treatment at Tumor Diagnosis and Treatment Center, Huashan Hospital Affiliated to Fudan University from April 2022 to April 2023 were selected as the research objects. The Pittsburgh Sleep Quality Index (PSQI) was used for evaluation. Patients with PSQI ≥8 points were included in the occurrence group, and patients with PSQI <8 points were included in the non-occurrence group. The general sociological and disease-related characteristics of the patients, such as education, chemotherapy or targeted therapy, somatic symptoms and other features were collected. χ2 test was performed first to determine the difference between two groups, and Logistic regression analysis was used to identify the predictors of sleep disorders in Cyber Knife patients. Results: A total of 101 Cyber Knife patients were included in this study, of which 43 patients (42.58%) without sleep disorders were included in the non-occurrence group. There were 22 cases (21.78%) of mild disorder, 22 cases (21.78%) of moderate disorder, and 14 cases (13.86%) of severe disorder, all of which were included in the occurrence group. There were significant differences in education level (primary and junior high schools: 32 (55.17%) vs. 15 (34.88%) patients, p = 0.043), family monthly income (≤5000 CNY (1 USD = 6.48 CNY): 36 (62.07%) vs. 15 (34.88%) patients, p = 0.007), somatic symptoms (35 (60.34%) vs. 17 (39.53%) patients, p = 0.038), self-rating anxiety scale (SAS) (>50: 32 (55.17%) vs. 15 (34.88%) patients, p = 0.043), self-rating depression scale (SDS) (>53: 35 (60.34%) vs. 18 (41.86%) patients, p = 0.038), numerical rating scale (NRS) (>3: 30 (51.72%) vs. 13 (30.23%) patients, p = 0.031) between the group of occurrence and no occurrence group. Education level (odds ratio (OR) = 2.845, p = 0.038), somatic symptoms (OR = 2.666, p = 0.048), SAS (OR = 2.889, p = 0.042), SDS (OR = 2.928, p = 0.027) and NRS (OR = 2.981, p = 0.025) had a statistically significant effect on sleep disorders in Cyber Knife patients. Conclusions: Cyber Knife patients are prone to sleep disorders during treatment. It is necessary to pay more attention to and take measures to reduce the occurrence of sleep disorders in clinical practice.

A Study on the Employment Support Service System for Visually Impaired College Students in China

At present, the problem of difficult employment for disabled college students in China is becoming more and more prominent, and the construction of an employment support service system for colleges and universities is one of the most important means of alleviating the employment pressure on disabled college students and promoting the healthy development of society. Based on the perspectives of visually impaired college students and colleges and universities, this study adopts qualitative research methods such as interview method and observation method, selects 10 visually impaired students from a college in China as the research object, and statistically analyses the raw data of the interviews with NVivo data analysis tools, and builds a college employment support service system with the core of education and training and support, employment guidance and consulting, social resources integration and enhancing social and enterprise inclusiveness. The service system is of great practical significance for promoting high-quality employment and better integration of visually impaired students into society, as well as creating a harmonious and inclusive employment support environment.

RESEARCH ON THE INCLUSIVE EDUCATION ADAPTABILITY OF VISUALLY IMPAIRED COLLEGE STUDENTS IN CHINA

The education of visually impaired students in China has also gone through a developmental stage from "segregated education" to "special education" and then to "inclusive education". In this paper, we take the visually impaired students at Binzhou Medical College, the first university in China to provide higher education for the disabled, as the research object. The study was carried out to investigate the adaptability of visually impaired students, using various research methods such as literature review method, questionnaire method and case study method, we investigated and researched the adaptation of visually impaired students to inclusive education from several aspects such as quality of life, social support, mental health level, self-esteem and self-efficacy study. Finally, the study proposed several countermeasures and suggestions, such as attaching importance to the physical and psychological rehabilitation of visually impaired students, emphasising the inclusive of education and rehabilitation, strengthening the training of professional teachers for visually impaired students, emphasising the complementarity between schools and professions, and improving the employment support service system for visually impaired students, which are of great significance in promoting the development of the cause of inclusive education for visually impaired students and improving the adaptability of inclusive education for visually impaired students.

An Efficiency Evaluation and Driving Effect Analysis of the Green Transformation of the Thermal Power Industrial Chain: Evidence Based on Impacts and Challenges in China

The high carbon emissions and pollution of China’s thermal power industry chain have exacerbated environmental and climate degradation. Therefore, accelerating the green transformation process is of great significance in promoting the sustainable development of enterprises. This study selected 30 listed thermal power enterprises in China as research objects, analyzed their data from 2018 to 2022, set targeted input–output indicators for different stages, and used a two-stage dynamic data envelopment analysis (DEA) model to evaluate and measure the efficiency of the green transformation of Chinese thermal power enterprises. In addition, this study also uses the logarithmic mean Divisia index (LMDI) method to analyze the driving effects of green transformation. The results indicate that in terms of overall efficiency, there is a significant difference in the overall performance of these 30 thermal power enterprises, with a large difference in average efficiency values. Efficiency values are related to enterprise size. In terms of stage efficiency, the average efficiency value of thermal power enterprises in the profit stage was significantly higher than that in the transformation stage, and the profitability of Chinese thermal power enterprises was better. In terms of sub-indicator efficiency, the efficiency of each indicator shows a “U”-shaped trend, and there is a certain correlation between the operating costs and revenue of thermal power enterprises, the market value of green transformation, and related indicators. In addition, the most important factor affecting the efficiency of green transformation is the sewage cost they face, whereas their operational capabilities have the least impact on their green transformation. In this regard, thermal power enterprises should increase their investment in the research and development of key technologies for thermal power transformation and continuously optimize their energy structure. The government will increase financial support for thermal power green transformation enterprises and correspondingly increase emission costs.

Social Cluster and Heritage Memory: A Study on the Space Perception of Zhaozhou Basin Horse Caravan Vernacular Architecture

Located in Dali, Yunnan, the Zhaozhou basin is home to many precious architectural heritages, particularly the historical horse caravan architecture. These buildings face the challenge of renewal and transformation. It is of great significance to explore the local population’s awareness of the architectural heritage of the horse caravan in order to protect the architectural heritage and facilitate rural revitalization. This study reviews the related research on “space perception”, establishes a theoretical framework of space perception under the architectural dimension, and develops hypotheses. The social cluster of typical settlements in the Zhaozhou basin is selected as the research object, and empirical analyses are carried out using SPSS and AMOS software. An analytical framework model of empirical research is constructed to evaluate the space perception of the current social population. The results of the reliability and validity tests of the questionnaire show that the CR is greater than 0.7 and that the AVE is greater than 0.5. The value of the structural equation model fitting index χ2/df is 1.863, which is less than 3. The model test results show that research hypotheses H1–H5 are supported; that is, space perception has a significant positive impact on cognition and local identity, cognition has a significant positive impact on local identity and space function, and place identity has a significant positive impact on space appeal. This study demonstrates the relationship between space perception and the architectural remains of the horse caravan, and it analyzes the human psychological perception behind the material space. The findings support the need for further conservation of the horse caravan architecture. This study further deepens the theory of space perception and its application in the study of vernacular architecture, which can provide a research path for the protection and development of vernacular architectural heritage.

Quantitative Analysis of Aeolian Sand Provenance: A Comprehensive Analysis in the Otindag Dune Field, Central Inner Mongolia, China

The identification and quantification of aeolian sand contributions are essential for understanding the formation of dune fields and mechanisms of modern surface processes. In the present study, we take aeolian sand in the Otindag dune field (hereafter, often referred to as, simply, Otindag) as the research object. The dune field’s immediate source is quantitatively identified based on heavy minerals and the Conservativeness Index (CI), Consensus Ranking (CR), and the Consistent Tracer Selection (CTS) method. The primary source area of the aeolian sand was found to be from the northwestern, upwind area of the Otindag (59 ± 14%), followed by the Yinshan Mountain (17 ± 10%) and the lake basin (23 ± 12%). The proposed sediment transport model elucidates that sediments from the upwind of the Otindag are directly transported from the northwest to the Otindag, where they are deposited. Materials from the southern Yinshan Mountains are carried by rivers to the southern edge of the Otindag, where they are subsequently transported by wind and ultimately deposited. The lake deposits within the Otindag also contribute to the aeolian sand supply under the influence of wind. This study demonstrates that the fingerprinting techniques of CI, CR, and CTS serve as successful strategies for conducting quantitative provenance research in dune fields.

Analysis of Learning Difficulties in Junior High School Students on Two-Dimensional Space

Purpose: This research aims to analyze the difficulties experienced by junior high school students with two-dimensional space concepts. Methodology: This quantitative research employs a descriptive approach. The subjects were 30 seventh-grade students at Pekanbaru Da'wah Middle School, Indonesia. The research object is the students' test results regarding the concept of two-dimensional space. Data collection involved asking students to complete essay test questions. Findings: The results show that 50% of students had difficulty with the indicator "Applying concepts to solve problems." For the indicator "Using appropriate formulas and completing calculations correctly and accurately," 43.3% of students (13 out of 30) struggled. Regarding the indicator "Relating problems to everyday life," 30% of students (9 out of 30) experienced difficulties. Significance: The next stage is grouping students' abilities according to the indicators. It can be concluded that seventh-grade students at SMPN 1 still experience difficulties with questions on two-dimensional space.

Robust controller design and experimental validation based on bounded uncertainty for collaborative industrial robots.

In this paper, derived from the proportional-derivative control and robust control, a novel practical robust control method based on a dynamic feedforward model is established by taking six-axis motion cooperative industrial robots as the research object. The nonlinear friction, parameter uncertainty, and external disturbance are taken into consideration while establishing the dynamic model of the cooperative industrial robot. The method includes a proportional-derivative control and a robust control. Lyapunov theory is used to analyze the proposed controller, and it is shown that this method can guarantee uniformly bounded and uniformly final bounded systems. Simulation and experiment results show that the proposed controller is better than proportional-integral-derivative control and mode-based proportional-derivative control in stability tracking performance and robustness. In addition, the CSPACE platform for rapid controller prototyping may reduce the arduous programming effort and offer a lot of ease for the trials.

Research on dimple suppression in multi-point flexible stretch forming of parabolic spherical part

Multi-point flexible stretch-forming process applies the idea of discretization to the die and clamp of stretch-forming, so that the die and clamp have high flexibility at the same time. Because the surface of the multi-point die is discontinuous, the sheet metal will produce the dimple during the forming process, which will affect the forming effect. To suppress the dimple, this paper takes parabolic spherical parts as the research object, and discusses the influence of swinging unit and discrete elastic cushion on the dimples of forming parts by numerical simulation. The results show that the strain and thickness distribution are more uniform and the dimples on the surface of the forming parts are obviously reduced when the swinging unit is used. The use of discrete elastic cushions on the fixed unit and the swinging unit can further suppress the dimples of the forming part and improve the forming accuracy. To verify the correctness of the numerical simulation, the multi-point die for swinging unit with discrete elastic cushion was used to carry out the flexible stretch-forming test of the parabolic spherical part. The test results are in agreement with the numerical simulation results, which shows that the methods are reliable and feasible.

Thermal Characteristics of Oil Film in Critical Lubrication State of Heavy Hydrostatic Bearing

Background: Lubrication failure has always been a concern in the research of heavy hydrostatic bearings. A preliminary study found that under a certain working condition, the heavy hydrostatic bearing will appear in the condition of zero local flow of oil film, which is called a critical lubrication state. It produces a significant thermal accumulation effect and affects the lubrication performance of the bearing. Objective: This paper takes Q1-205 double rectangular cavity hydrostatic thrust bearing as the research object and adopts the research method combining theoretical analysis, simulation, and experimental test to analyze the temperature rise and characteristics of the bearing when it is in critical lubrication state under different working conditions. Methods: The finite volume method is used to simulate the critical lubrication state under the condition of common load and rotating speed, and the corresponding operating parameters of the critical lubrication of heavy static support are obtained. Results: It is found that when the oil film is in the critical lubrication state, the low temperature zone is concentrated at the bearing position of the oil film, while the high temperature zone is concentrated at the counter-current side sealing edge Conclusion: The oil film's local temperature rise is intensified, and the heat accumulation phenomenon is serious because the heat cannot be taken away in time.

Analysis of dynamic evolution characteristics and driving factors of regional synergistic effect of reducing carbon and saving water: the case of Yangtze River Delta Urban Agglomerations, China.

Carbon emissions and water consumption are both important factors affecting sustainable development. Therefore, it is necessary to put them in the same research framework and investigate the synergy. In this study, the dynamic evolution characteristics of the synergistic effect of reducing carbon and saving water (RCSW) were analyzed. Then, taking the Yangtze River Delta Urban Agglomerations (YRDUA) as the research object, the influencing factors and specific paths of the synergistic effect were clarified. The results showed that the low-carbon emission efficiency (LCEE) had a stable synergy with the intensive utilization efficiency of water resources (IUEWR) in the YRDUA. Government financial expenditure, actual use of foreign capital, and population density were the most significant driving forces for the synergistic effect of RCSW, with q values of 0.561, 0.363, and 0.240, respectively. In addition, most of the interactions of the driving factors were nonlinear enhancement and double-factor enhancement.

Rapid Identification Model of Mine Water Inrush Source Using Random Forest Optimized by Multi-Strategy Improved Sparrow Search Algorithm

Mine water inrush accident is one of the most threatening disasters in coal mine production process. In order to improve the identification accuracy of mine water inrush source, a fast identification method of mine water inrush source based on improved sparrow search (SSA) algorithm coupled with Random Forest algorithm was proposed. Firstly, taking Zhaogezhuang Mine as the research object, six factors were selected as the discriminant index and three principal components were extracted by kernel principal component analysis. Secondly, four strategies are employed to enhance the SSA for achieving the ISSA, while multiple benchmark functions are utilized to validate its performance. The extracted principal components serve as input, and the categories of water inrush sources act as output. Subsequently, the prediction results of Random Forest (RF) algorithm after optimizing hyperparameters through Improve SSA are compared with those obtained from other models. The research findings demonstrate that optimizing the RF model using Improve SSA yields superior predictive performance compared to alternative models. Finally, this model is applied to identify water inrush sources in a mine located in Shandong province. The discrimination results exhibit higher accuracy, precision, recall, and F1 index than other models, thereby confirming the reliability and stability of this approach. The results demonstrate that the kernel principal component analysis-based rapid identification model for mine water outburst source, combined with an improved sparrow search algorithm to optimize Random Forest, exhibits excellent robustness and accuracy. This model effectively fulfills the requirements of identifying mine water outbursts and provides a reliable guarantee for ensuring mining safety production.

From “screen-as-writing” theory to Internet culturology. A French perspective on digital textualities

ABSTRACT To which extent do we conceptualise digital research objects through the lenses of the Humanities, within the frame of a long-term cultural history or from the standpoint of a particular intellectual tradition? This paper aims at acquainting global English-speaking researchers with a localised French perspective on digital textualities. In the framework of what has been called the “screen-as-writing” theory (théorie des écrits d’écran), a review of Emmanuël Souchier and Yves Jeanneret’s seminal contributions shows how a French literary heritage led to the development of an original set of concepts for analysing digital textualities. Throughout an autoethnographic journey, their “socio-semiotic” approach is discussed, highlighting collective uses of several key concepts (architexts, passing signs, etc.) for the understanding of hypertextual objects (software, cd-roms, websites, blogs, social media platforms and apps) and contemporary cultural Internet expressions (buzzwords, experiences, gestures).