Results Of Research Research Articles

Chinese expert consensus on the perioperative medication in laser corneal refractive surgery (2024)

With the increasing incidence of myopia year by year and the continuous progress of various treatment techniques, laser corneal refractive surgery has become one of the important ways to correct refractive errors. The rational drug use in the perioperative period is important for the success of surgery and reduction of complications. In 2019, based on the development of laser corneal refractive surgery in China, experts from the Refractive Surgery Experts Group of Ocular Microcirculation Branch of Chinese Society of Microcirculation and the Ophthalmology Branch in the Chinese Medical Association formed the "Chinese Expert Consensus on the Perioperative Medication in Laser Corneal Refractive Surgery (2019)". To further promote the expansion of new clinical technologies and surgical methods, and to improve surgical efficacy, the Refractive Surgery Experts Group of Ocular Microcirculation Branch of Chinese Society of Microcirculation, according to the latest domestic and foreign research results, has recently updated the consensus after a collective discussion.

Using the UTAUT-TPACK model to explain digital teaching behaviour of elementary school mathematics teacher

ABSTRACT The appropriate use of digital technology in the classroom is very helpful to improve mathematics teaching in elementary school. However, the current situation of elementary school mathematics teachers’ digital teaching behaviour is not optimistic. This study analysed the factors influencing elementary school mathematics teachers’ digital teaching behaviour. A revised unified theory of acceptance and use of technology (UTAUT) model with technological pedagogical content knowledge (TPACK) was used to understand elementary school mathematics teachers’ digital teaching behaviour. A questionnaire survey was conducted in Hunan province of China. Three hundred elementary school mathematics teachers provided valid questionnaire data. The partial least squares structural equation modelling (PLS-SEM) approach was used to analyse the data. It was found that TPACK and facilitating conditions positively and significantly affected digital teaching behaviour of elementary school mathematics teachers, and TPACK was the biggest influential factor. The research results have important implications for improving digital teaching behaviour of elementary school mathematics teachers and promoting digital transformation of elementary school mathematics education.

ANALISIS KETAHANAN PANGAN RUMAH TANGGA PETANI PADI SAWAH DI DESA MONAPA KECAMATAN MOWILA KABUPATEN KONAWE SELATAN

This study aims to find out (1) How is the food security of paddy rice farming households in Monapa Village, Mowila District, South Konawe Regency; (2) Factors affecting the food security of rice farming households in Monapa Village, Mowila District, South Konawe Regency, with a total sample of 63 respondents using the slovin formula. To answer the first goal using the measurement of the share of food expenditure. For the second purpose using multiple linear analysis. Based on the results of research on the food security of lowland rice farmer households in Monapa Village, Mowila District, South Konawe Regency, the majority of 65.08% of households fall into the food insecure category (share of food expenditure ≥ 60%) and the remaining 34.92% of households included in the category of food security (share of food expenditure ≤ 60%). The factor that has a significant effect on the food security of paddy rice farming households in Monapa Village, Mowila District, South Konawe Regency is household income with a significant value of 0.032 which is less than the value of α (0.05). While the variables of the number of family members, the education of the housewife, the price of rice and eggs have no significant effect on the food security of rice farming households.

The Effect of Artificial Ageing on the Changes in Selected Properties of Organic Coated Sheets

This contribution presents the results of research focused on changes in selected properties of organic-coated steel sheets in a corrosive environment of salt mist. The aim of this study was to characterise coated sheets and to analyse the influence of elevated temperature on changes in their selected properties. The methodology and experiments were chosen to simulate the accelerated ageing and to evaluate the surface of organic-coated steel sheets. During the research, the effect of artificial ageing due to increased temperature on changes in mechanical properties of coated sheets was monitored, which were determined by tensile testing according to STN EN 10002-1. The fracture surface of the test samples was analysed using a SEM. The following observations were made for the evaluation of coating by cross-cut tests according to EN ISO 2409. Corrosion tests were carried out by conducting salt spray corrosion tests according to EN ISO 9227. The test specimens were artificially sectioned using a laser beam. The results of the research experiments confirmed the assumption that the utilisation of the laser beam was convenient for the creation cross–cut test of the material. After the ageing test, only small significant changes in the basic mechanical properties of the tested materials were observed. It is necessary to take into account that there were changes in the appearance of the coating. The cross-cut test confirmed the results that the plastic-coated sheets could be utilised in salt corrosion environments.

Experimental Study on Explosion Characteristics of LPG/Air Mixtures Suppressed by CO2 Synergistic Inert Powder

In order to study the explosion suppression characteristics of LPG/air mixture by CO2 synergistic inert powder, explosion suppression experiments were conducted in a 20 L explosion device. The results show that the explosion suppression effect of NaHCO3 powder is prior to Al(OH)3 powder under the condition of no CO2 synergy. As the mass concentration of inert powder increases, the peak value of explosion pressure Pex and the peak value of the pressure rise rate (dP/dt)ex decrease, and the explosion suppression effect gradually enhances. Gas–solid two-phase inhibitors exhibit more significant inhibitory effects than single-phase inhibitors. Increasing the volume fraction of CO2 or the mass concentration of inert powder can improve the explosion suppression effect. The explosion suppression effect of CO2/NaHCO3 is significantly better than that of CO2/Al(OH)3. The research results have certain significance for the prevention and control of LPG explosion accidents.

Anomaly detection combining bidirectional gated recurrent unit and autoencoder in the context of e-commerce

E-commerce platforms store a large amount of user personal information, transaction data, and financial information, which have extremely high value for hackers and criminals. Therefore, protecting the security of e-commerce platforms is particularly important, and intrusion detection is a technical means used to discover and respond to possible security threats and attacks. But with the development of Internet technology, there are more and more types of intrusion attacks and more sophisticated means. Traditional intrusion detection systems are difficult to cope with. This study proposes an anomaly detection model based on bidirectional gated loop units and autoencoders. The model learns HTTP text data, trains the model, and uses bidirectional gated loop units to convert text sequences from characters to numbers. The experimental results show that when the training set size is 1000, the false alarm rates of Analytic Hierarchy Process, Support Vector Machine, Long Short Term Recurrent Memory Network, and Improved end-to-end algorithm models are 0.30, 0.27, 0.23, and 0.10, respectively. The loss function values are 0.35, 0.28, 0.17, and 0.13, respectively. The F1 values are 0.78, 0.88, 0.91, and 0.99, and the accuracy rates are 0.88, 0.91, 0.95, and 0.99, respectively. The research results indicate that the proposed method model has excellent performance.

Study on the Influencing Factors of Electrical Characteristics of Articulated Split-Zone Insulator Arc

The frequent occurrence of the pantograph–catenary (PC) arc seriously threatens the safe and stable operation of electric multiple units (EMUs). In order to investigate the primary factors affecting the electrical characteristics of the PC arc, this paper first reveals the mechanism of arc generation when EMUs leave the split-zone insulator according to the actual mechanical structure of the PC articulated split-zone insulator. Then, based on the Habedank black box arc model, considering the dynamic changes in arc length during the actual operation of EMUs, a numerical simulation model suitable for describing the PC articulated split-zone insulator arc is established. Furthermore, by comparing with existing research results, the effectiveness of the proposed model is verified. Next, a series of simulation experiments were conducted to analyze the influence of different operating parameters of the EMUs on the electrical characteristics of the PC arc. More importantly, the paper proposes using the entropy weight method to calculate the impact strength of different operating parameters of the EMUs on the arc duration time of the contact wire split-zone region. The research results of this paper can provide some technical references for reducing the erosion of the PC contact wire and slide caused by arcs when the EMUs pass through the split-zone insulator.

Numerical Calculation and Application for Crushing Rate and Fracture Conductivity of Combined Proppants

Proppant is one of the key materials for hydraulic fracturing. For special situations, such as middle-deep reservoirs and closure pressures ranging from 40 MPa to 60 MPa, using a single proppant cannot solve the contradiction between performance, which means crushing rate and fracture conductivity, and cost. However, using combined proppants is an economically effective method for hydraulic fracturing of such special reservoirs. Firstly, for different types, particle sizes, and proportions of combined proppants, various contact relationships between proppant particles are considered. The random phenomenon of proppant particle arrangement is described using the Monte Carlo method, and the deterministic phenomenon of proppant particles is processed using an optimization model, achieving computer simulation of the microscopic arrangement of proppant particles. Secondly, a mathematical model for the force analysis of combined proppant particles is established, and an improved singular value decomposition method is used for numerical solution. A computational model for the crushing rate and fracture conductivity of combined proppants is proposed. Thirdly, the numerical calculation results are compared and discussed with the test values, verifying the accuracy of the computational model. Finally, the application of combined proppants is discussed, and a model for optimizing the proportion of combined proppants is proposed. The onsite construction technology is introduced, and the cost and economic benefits of combined proppants are compared with those of all ceramic particles and excessive all-quartz sand. It is proved that combined proppants can balance performance and price, and are an economically effective method for hydraulic fracturing of special reservoirs. The research results can select the optimal proppant material and optimize the combination of different proppant types, which can help achieve cost reduction and efficiency increase in oil and gas development.

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.

Influence of graphene on the composite modified asphalt based on viscoelastic and elastic properties

In order to explore high-viscosity, high-elasticity composite modified asphalt materials suitable for drainage pavements, different dosages of graphene-modified asphalt and graphene composite-modified asphalt were prepared. Elastic recovery efficiency and rotational viscosity as the main experimental indicators for modified asphalt are employed to determine the optimal dosage of graphene and help conduct a study on the viscoelastic properties, analyzing the fatigue performance of the modified asphalt through linear amplitude sweep (LAS). Based on molecular dynamics simulation (MD) to build an asphalt model, the study on viscoelastic properties uses calculated viscosity and the asphalt glass transition temperature range (Tg) obtained from simulation results as indicators to verify the optimal dosage of graphene. Scanning Electron Microscopy (SEM) is utilized to reveal the effects of different dosages of graphene modification. The research results indicate that the optimal dosages of graphene in graphene-modified asphalt and graphene composite-modified asphalt are 0.1 % and 0.2 %, respectively. At these concentrations, graphene significantly enhanced the elastic recovery properties of the matrix asphalt (113 % increase) and the composite-modified asphalt (28 % increase). In terms of rotational viscosity, the matrix asphalt saw a 54 % rise with the addition of graphene, while the composite-modified asphalt experienced a substantial 151 % increase. Notably, the incorporation of graphene also resulted in a rise in the glass transition temperature and a reduction in the length of the graphene-modified asphalt, signifying an improvement in its elastic properties. Furthermore, the calculated viscosity of the graphene-modified asphalt and composite-modified asphalt surged by 47.49 % and 64.01 %, respectively. Additionally, SEM results indicate that differences in the effects of graphene modification are primarily due to the dispersion and coating extent of graphene.

Photoelectric conversion performance of Ga0.47In0.53As/Ge0.79Sn0.21 dual-junction thermophotovoltaic cell

Abstract Based on the photovoltaic characteristics of GeSn-based materials and the theory of stacked solar cells, Ga0.47In0.53As/Ge0.79Sn0.21 dual-junction thermophotovoltaic cell has been simulated and studied for the first time. According to existing experimental material parameters, the structure of the cell is optimized, and the photoelectric performance of the cell is profoundly studied. The findings indicate that the doping concentrations of the top/bottom cell are Na(d),t/Na(d),b=50(7)×1016/17(2)×1019 cm-3, which exhibits superior photoelectric conversion performance. For reducing material consumption and achieving high performance, the thickness of the emitter (base) of the top/bottom cell can be selected as 0.8~2.0(2.0~4.0)/0~0.2(1.0~4.0) µm (TBB=1500 K). With radiator temperatures increasing, the conversion efficiency of the cell significantly improves, and the open circuit voltage of the cell can reach 0.70~0.91 V (1000~2000 K). The research results can guide the design and fabrication of high-efficiency and economical GeSn-based multi-junction thermophotovoltaic cells, and can also provide a new research and development direction for low-cost thermophotovoltaic cells.

Meta-analysis of the association between chronic periodontitis and chronic kidney disease.

Many scholars have performed several clinical studies have investigated the association between chronic periodontitis (CP) and chronic kidney disease (CKD). However, there are still differences between these research results, and there is no unified conclusion. Therefore, a systematic review is required to understand this issue fully. To explore the correlation between CP and CKD. Literature on the correlation between CP and CKD, as well as the clinical attachment level (CAL) and pocket probing depth (PPD) of CKD and non-CKD, were retrieved from PubMed, Embase, the Cochrane Library, and Web of Science repositories until January 2024. After the effective data were extracted, data processing and statistics were performed using Stata 12.0. Of the 22 studies, 13 were related to CP and CKD, and 9 reported CAL and PPD in patients with CKD and healthy controls. Meta-analysis of the correlation between CP and CKD revealed that CKD probability in people with CP was 1. 54 times that of healthy individuals [relative risk = 1.54, 95% confidence interval (CI): 1.40-1.70], and CP incidence in patients with CKD was 1. 98 times that of healthy individuals [overall risk (OR) = 1.98, 95%CI: 1.53-2.57]. Meta-analysis of CAL and PPD evaluations between CKD patients and healthy individuals showed that CAL and PPD levels were higher in CKD patients [standard mean difference (SMD) of CAL = 0.65, 95%CI: 0.29-1.01; SMD of PPD = 0.33, 95%CI: 0.02-0.63]. A bidirectional association exists between CP and CKD. CKD risk is increased in CP patients and vice versa. Periodontal tissue or tooth loss risks increase over time in CKD patients.

Effect of Composite Fibers and Fly Ash on the Properties of Portland–Sulfoaluminate Composite Cement-Based Grouting Sealing Materials

Current conventional cement materials are no longer able to meet the actual usage needs of geotechnical engineering. In order to improve the workability of cement materials used in geotechnical, transportation, and mining engineering, it is necessary to improve the formulation of cement materials. Polypropylene fibers (PVAF), polyvinyl alcohol fibers (PPF), and fly ash (FA) are used in this study to modify Portland–sulfoaluminate composite cement to improve the workability of the cement material system. Meanwhile, the microstructure that affects the system performance was also studied. The research results indicate that adding FA to the composite cement system can improve its fluidity. In the later stage of hydration, due to the volcanic ash reaction, the production of hydration products will increase, but it will not affect the type of hydration products. Adding PPF-PVAF can effectively improve the strength performance of the cement system. The compressive strength reached 24.61 MPa after 28 days of curing, which was 13.8% higher than the blank sample. Adding calcium hydroxide powder and FA to the system can improve the fluidity of the cement system to a certain extent and positively impact the later strength. After 28 days of curing, the compressive strength of experimental group 9 reached 30.21 MPa, which increased by 70.5% compared to after 7 days These results were found at the microscopic level, based on analyses via XRD, TG, and SEM. The Mix-EXP cured for 28 days has better hydration product content and composition arrangement of cement slurry than the O-S-C cured for 28 days.

Evaluation of different operational conditions in a microbial electrolysis cell inoculated with a pure culture of Shewanella oneidensis for hydrogen production.

Hydrogen is a promising alternative to meet the world's energy demand in the future because of its energetic characteristics. Microbial electrolysis cell (MEC) produces hydrogen from organic matter using exoelectrogenic bacteria. Shewanella oneidensis stands out for having the capacity to produce hydrogen using different electron transfer mechanisms. The present research aims to evaluate the hydrogen production efficiency in a MEC inoculated with a pure culture of S. oneidensis in different operational conditions. Since the use of a catalyst accounts for most of the MEC cost, no catalyst was used for anode or cathode. Experiments were performed in semi-continuous and batch mode using different electrodes, voltages applied, and medium in aerobic and anaerobic conditions. The highest hydrogen production rate (HPR) was 0.107 m3 of H2/m3day obtained in a semi-continuous experiment using graphite plates and stainless steel electrodes. In batch experiments, a HPR occurred at 0.7V, with a value of 0.048 m3 of H2/m3day versus 0.037 m3 of H2/m3day with 0.9V. HPR was higher with carbon felt electrode (0.056 m3 of H2/m3day). However, current density dropped after 38h, with carbon felt electrodes, and did not recover. Results of the present research showed that the MEC using a pure culture of S. oneidensis can be considered an alternative for hydrogen production without using a catalyst. Also, S. oneidensis produced hydrogen in both anaerobic and aerobic conditions with low methane production. Optimization can be proposed to improve hydrogen production based on the operational conditions tested in these experiments.

Cost reduction for upscaling voluntary sustainability standards: the case of independent oil palm smallholders in Central Kalimantan, Indonesia

Upscaling Voluntary Sustainability Standards (VSS) can generate ecological and social benefits at a scale that is meaningful to address pressing environmental issues such as climate change and biodiversity losses. Lack of resources and risks of implementation gaps may, however, hinder the success of upscaling VSS. This paper aims to fill the gap in the literature regarding options to reduce certification costs to upscale VSS amid the limited financial resources available for certification. The paper presents the result of action research involving 3,507 independent oil palm farmers who are members of six farmer groups in two districts in Central Kalimantan to achieve Roundtable on Sustainable Palm Oil (RSPO) certification. The research found that achieving economies of scale by increasing the total number of certified farmers can reduce the certification costs per farmer. By establishing a district-level entity, the costs related to audits, RSPO membership fees, and the establishment of farmer groups, such as developing standard operating procedures (SOPs), can be lowered. Implementation gaps were not found with the increase of farmers joining the project based on the training frequency and the external audit findings reports on farmers' compliance with RSPO principles and criteria. The findings of this study provide a basis for promoting the upscaling of VSS, including through the RSPO jurisdictional approach.

Antioxidant Activity and Preclinical Safety of Semen persicae Extract

Semen persicae is the dried mature seeds of Prunus persica (L.) Batsch and P. davidiana (Carr.) Franch and is commonly used in traditional Chinese medicine (TCM) formulations because of its variety of biological effects. The present study aimed to evaluate the antioxidant activity and toxicity profiles of semen persicae extract (SPE) after determining the amygdalin content (4.95%) using HPLC. Regarding the in vitro antioxidant activity, SPE with 2 mg/mL concentration scavenged 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl, and ABTS free radicals with rates of 51.78%, 55.47%, and 57.16%, respectively. The same concentration of SPE chelated 30.76% Fe2+. The in vitro cytotoxicity study revealed that SPE induced 92.45% cell viabilities of HEPG2 even at 2000 μg/mL. In the acute toxicity study, oral administration of SPE did not provoke mortality or any toxic signs at doses up to 2000 mg/kg bw. Repeated oral administration for 28 days at doses of 100, 300, and 600 mg/kg per day in rats did not show any toxicity signs or gross pathological abnormalities. The results of the present research provide basic reference data for SPE with a moderate effect on antioxidant activity and low toxicity for future screening of biological and pharmacological properties.

Understanding the role of H2O in heterogeneous catalysis of COX hydrogenation

The effects of H2O in heterogeneous catalysis of COx (CO2, CO) hydrogenation have been intricate and controversial for many years. On the one hand, H2O molecules and their derivatives (O, H, OH) serve as reactants or co‐reactants, playing a role in modulating the reaction pathway through specific mechanisms. On the other hand, the presence of H2O can influence the catalytic performance by altering the physicochemical properties of the catalyst, such as particle size and chemical state, among others. More importantly, the dual role of H2O leads to both positive and negative outcomes, challenging our understanding of its impact. In this mini review, the relevant research results are summarized in terms of the promoting and inhibiting effects of H2O of the COx hydrogenation reaction (e.g., synthesis of methanol, Fischer‐Tropsch synthesis, methanation, etc.) and discussed from the perspective of catalyst and reaction mechanism, which may provide a certain theoretical basis for the design and development of high‐performance catalysts and referable experience for the further exploration and utilization of H2O effects on related fields as well.

Mapping the Landscape of Carbon-Neutral City Research: Dynamic Evolution and Emerging Frontiers

Carbon-neutral city research has attracted widespread attention. However, a comprehensive review of this research has not been conducted, and it is unclear how the various perspectives have evolved. In this study, CNKI and Web of Science were used as data sources. By summarizing the research results of carbon-neutral cities in recent years, the dynamics evolution trend is revealed, and the frontiers are explored. We found that: (1) the themes and contents of carbon-neutral city research were diverse and intersecting and mainly focused on energy, industrial structure, transportation, and building. (2) The knowledge map of author cooperation did not show many aggregates, which indicated that the cooperation and exchanges between relevant researchers are insufficient. (3) Chinese research on carbon-neutral cities was extensive and fruitful, taking the lead in the research in this field. Based on the current situation and trends, we provided a scientific reference for the development of carbon-neutral cities. Current research foci and cutting-edge findings will help to make cities more climate resilient, sustainable and livable. Understanding and magnifying these foci is what will help countries achieve their climate mitigation and carbon neutrality goals sooner rather than later.

Партнерство классного руководителя и семьи по вопросам воспитания младших школьников

The article discusses the leading areas of implementation of the partnership between the class teacher and the family on the education of primary schoolchildren and the results of research on this problem. The partnership of the school and parents is the creation of conditions for the formation of personality, self-determination and socialization of the child. Today, the school and family, as social institutions, as equal subjects of upbringing of the younger generation, are tasked with fostering patriotism and citizenship; assignment of norms, values and traditions of Russian society. Partnerships are seen as unity the goals and values of family and school education. The interaction of the class teacher and parents allows you to jointly identify, realize and solve the problems of raising children, and also provides the necessary deep connections between adults in the context of the development of the child's personality.

Dynamic response and blast resistance of I‐shaped steel‐concrete composite beam under explosive loading

AbstractTo investigate the dynamic mechanical response and damage mechanisms of I‐shaped steel‐concrete composite beams under explosive loads, experimental research and numerical simulations were conducted on steel‐concrete composite structures. The accuracy of the numerical analysis model was validated by comparing the damage characteristics of the structures obtained from explosive tests on the steel‐concrete composite components. Based on this, numerical simulations were performed on steel‐concrete composite beams using the explicit dynamic analysis software ANSYS/LS‐DYNA, and a study on their damage mechanisms was conducted. This study resulted in the acquisition of dynamic mechanical response patterns, including time‐dependent stress, strain, displacement, acceleration, and so on. Different structural damage characteristics under various explosive conditions were summarized, and key parameters affecting the blast resistance of the structure were analyzed. The research findings indicated that, in contrast to the failure characteristics of I‐shaped reinforced concrete (RC) beams, the failure characteristics of I‐shaped steel‐concrete composite beams mainly include punching and shearing failure of the steel‐RC slab and local buckling of the steel beam. Under the same explosive conditions, steel‐concrete composite structures exhibit superior blast resistance, with certain changes in structural parameters significantly improving blast resistance. The research results can provide theoretical support and a scientific basis for the proactive design of blast protection in steel‐concrete beams.