Grindability Evaluation of Ultrasonic Assisted Grinding of Silicon Nitride Ceramic Using Minimum Quantity Lubrication Based SiO_(2)Nanofluid

Minimum quantity Lubrication(MQL)is a sustainable lubrication system that is famous in many machining systems.It involve the spray of an infinitesimal amount of mist-like lubricants during machining processes.The MQL system is affirmed to exhibit an excellent machining performance,and it is highly economical.The nanofluids are understood to exhibit excellent lubricity and heat evacuation capability,compared to pure oil-based MQL system.Studies have shown that the surface quality and amount of energy expended in the grinding operations can be reduced considerably due to the positive effect of these nanofluids.This work presents an experimental study on the tribological performance of SiO_(2)nanofluid during grinding of Si_(3)N_(4)ceramic.The effect different grinding modes and lubrication systems during the grinding operation was also analyzed.Different concentrations of the SiO_(2)nanofluid was manufactured using canola,corn and sunflower oils.The quantitative evaluation of the grinding process was done based on the amount of grinding forces,specific grinding energy,frictional coefficient,and surface integrity.It was found that the canola oil exhibits optimal lubrication performance compared to corn oil,sunflower oil,and traditional lubrication systems.Additionally,the introduction of ultrasonic vibrations with the SiO_(2)nanofluid in MQL system was found to reduce the specific grinding energy,normal grinding forces,tangential grinding forces,and surface roughness by 65%,57%,65%,and 18%respectively.Finally,regression analysis was used to obtain an optimum parameter combinations.The observations from this work will aid the smooth transition towards ecofriendly and sustainable machining of engineering ceramics.

Geological Analogy Expert System of Oil-Generating Depressions

The geologic analogy expert system of oil-generating depressions (GAESOD) constructed on IBM 386 by using GCLISP language is a tool-type expert system for geologic analogy .GAESOD consists of eight parts: (1) illustrating module of system; (2) general controlling module; (3) knowledge base; (4 (reasoning module; (5 )data base; (6)explanation module; (7)gaining and managing module of knowledge; (8) managing module of data base .There are 36 known models of oil-generating depressions of the eastern part and the continental shelf of China in the knowledge base .Three values,such as resemblance coefficient ,certainty factor and fine-poor coefficient ,will be acquired if this system is applied to any two on-generating depressions .Finally,GAESOD are applied to the analysis of some data from Xichang depression ,Hepu basin and the conclusions from this system are consistent with the results from geologic experts.

An analogical study of wave equations,physical quantities,conservation and reciprocity equations between electromagnetic and elastic waves

This paper presents an analogical study between electromagnetic and elastic wave fields,with a one-to-one correspondence principle established regarding the basic wave equations,the physical quantities and the differential operations.Using the electromagnetic-to-elastic substitution,the analogous relations of the conservation laws of energy and momentum are investigated between these two physical fields.Moreover,the energy-based and momentum-based reciprocity theorems for an elastic wave are also derived in the time-harmonic state,which describe the interaction between two elastic wave systems from the perspectives of energy and momentum,respectively.The theoretical results obtained in this analysis can not only improve our understanding of the similarities of these two linear systems,but also find potential applications in relevant fields such as medical imaging,non-destructive evaluation,acoustic microscopy,seismology and exploratory geophysics.

The Effect of Mineral Composition and Quantity of Fines on the Atterberg Limits and Compaction Characteristics of Soils

Because of the various elements that come into play in natural soil formation, the impact of varied proportions of mineral composition and fines amount on Atterberg limits and compaction characteristics of soils is not well known. Three distinct soil samples were used in this investigation. The findings indicated the effect of varied mineral composition proportions and fines amount on the liquid limit, plastic limit, and plasticity index as assessed by the Casagrande test and hand-rolling method. The fluctuation of maximum dry density and optimal moisture content with these three soils has also been studied. Furthermore, correlations were established to indicate the compaction parameters and the amount of minerals and particles in the soil. The data show that the mineral content of the soil has a direct impact on the Atterberg limits and compaction characteristics. Soils containing larger percentages of expansive minerals, such as montmorillonite, have more flexibility and volume change capability. Mineral composition influences compaction parameters such as maximum dry density, ideal water content, axial strain, and axial stress. Soils with a larger proportion of fines, such as Soil 2 and Soil 3, have stronger flexibility and lower compaction qualities, with higher ideal water content and lower maximum dry density. Soil 1 has moderate flexibility and intermediate compaction qualities due to its low fines percentage. The effect of different mineral compositions and fines on the Atterberg limits and compaction characteristics of soils can be used to predict the behavior of compacted soils encountered in engineering practices, reducing the time and effort required to assess soil suitability for engineering use.

Objective Model Selection in Physics: Exploring the Finite Information Quantity Approach

Traditional methods for selecting models in experimental data analysis are susceptible to researcher bias, hindering exploration of alternative explanations and potentially leading to overfitting. The Finite Information Quantity (FIQ) approach offers a novel solution by acknowledging the inherent limitations in information processing capacity of physical systems. This framework facilitates the development of objective criteria for model selection (comparative uncertainty) and paves the way for a more comprehensive understanding of phenomena through exploring diverse explanations. This work presents a detailed comparison of the FIQ approach with ten established model selection methods, highlighting the advantages and limitations of each. We demonstrate the potential of FIQ to enhance the objectivity and robustness of scientific inquiry through three practical examples: selecting appropriate models for measuring fundamental constants, sound velocity, and underwater electrical discharges. Further research is warranted to explore the full applicability of FIQ across various scientific disciplines.

Effect of Earthworms on the Population Quantity of Meloidogyne incognita in Tomato Cultivation

[Objectives]The paper was to further investigate the correlation between the presence of earthworms and the occurrence of Meloidogyne incognita.[Methods]The effect of earthworms on the population quantity of M.incognita and the growth of tomato plants was assessed through a potting experiment utilizing Eisenia fetida and M.incognita as the primary subjects of investigation.[Results]E.fetida exhibited an inhibitory effect on both the reproductive capacity and the prevalence of M.incognita.Additionally,it mitigated the adverse effects of M.incognita on the growth and development of tomato plants.[Conclusions]The findings of this study will establish a theoretical framework for utilizing earthworms and their metabolites to modulate the rhizosphere microecological environment,thereby facilitating the management of M.incognita.

内蒙古黑岱沟露天煤矿抛掷爆破地方性震级与炸药量的经验关系

利用黑岱沟露天煤矿的爆破资料,开展黑岱沟煤矿抛掷爆破地方性震级与炸药量的关系的研究。为了避免矿山地震台网地震仪在长期观测中传递函数、归一化因子、放大倍数等参数出现错误,开展同址台站对比分析,实时监控、修订参数。实测结果显示,同址两台站记录到的爆破波形特征非常一致;使用矿山地震台网资料,采用5 km以内的地方性震级M_(L)的量规函数,测定了2023年5-8月4次爆破的地方性震级M_(L);联合使用矿山台网和内蒙古地震台网记录到的44次爆破的数据,采用正交回归方法,得到黑岱沟煤矿抛掷爆破地方性震级M_(L)与炸药量Y之间的经验公式为:M_(L)=3.15lg Y-6.88。

基于信息量模型的黑山峡地区滑坡易发性风险评价

滑坡是黄河黑山峡地区的主要地质灾害之一,在黑山峡水利枢纽建设前期工作中开展黑山峡地区滑坡易发性评价显得尤为必要。基于黑山峡地区地质条件、气候、人类活动等调查资料,选取高程、坡度、曲率、地层岩性、与断层的距离、与水系的距离、NDVI(归一化差分植被指数)、与道路的距离、降水量9个因子作为滑坡易发性评价指标,采用信息量模型进行滑坡易发性评价,通过对各因子的分级权重进行计算,得到滑坡易发性信息量值;通过对滑坡易发性信息量进行叠加与分区,绘制黑山峡地区滑坡易发性分区图,确定危险区域。结果表明:黑山峡地区滑坡灾害极高易发区位于东北部中卫市沙坡头区、南部靖远县以及主要河流与道路沿线,这些地区地层岩性较软弱,大多为砂、黄土等,在河流冲积与人类活动的影响下极易发生地表斜坡失稳。

区域创新改革政策如何影响城市碳排放的“减量增质”?——基于全面创新改革试验区的准自然实验

“双碳”目标既是我国对世界的庄重承诺,也是我国创新驱动发展战略的必然举措。稳妥推进“双碳”目标,需立足我国能源资源禀赋,逐步转向碳排放总量和强度“双控”制度,积极参与全球环境治理。论文以全面创新改革试验区城市为准自然实验,基于中国282个地级市2010—2019年面板数据,采用双重差分法检验试验区对城市碳排放“量”与“质”的影响及其作用机制。研究表明,试验区通过提高城市绿色创新能力以及产业集聚效应显著降低城市碳排放水平并提高城市碳生产率,在老工业基地城市以及非资源型城市效果更明显。结论有助于进一步扩大试验区的设立以推动城市碳减排可持续发展,并为碳减排政策提供进一步的决策参考。

低温冷风微量润滑技术对TC6钛合金加工特性的应用研究

目的探究机加工中低温冷风微量润滑技术对切削温度、材料塑性变形以及已加工表面质量的影响。方法针对TC6钛合金进行低温冷风微量润滑切削加工应用试验,对比常温干切削和–27℃低温冷风微量润滑切削以及改变加工参数对TC6材料已加工表面缺陷、微观形貌及粗糙度的影响规律,分析低温冷风微量润滑加工应用特点。结果相较于常温干切削,低温冷风微量润滑切削可以明显降低TC6材料在加工中因热量累积而导致的塑性变形,抑制了切削变形区材料与刀具因内摩擦加剧而导致的咬焊现象,减少了已加工表面黏屑、划痕、凹坑、撕裂、侧流等缺陷,有效提高了加工表面质量,与常温干切削加工相比,低温微量润滑切削的表面粗糙度值降低了19%;在加工参数为变量的切削中,提高进给量使已加工表面粗糙度值增加了49%,进给量对已加工表面质量的影响最大;提高背吃刀量使已加工表面粗糙度值增加了43%,背吃刀量对表面质量的影响次之;切削速度对表面质量的影响最小,但背吃刀量和切削速度的增加易使工艺系统产生振动,造成不稳定切削现象。结论将低温冷风微量润滑技术应用在TC6材料的加工上对提高加工质量、满足低碳工业的需求具有一定的帮助。

Icon memory research under different time pressures and icon quantities based on event-related potential

In order to obtain related brain electrical components and neural bases of physiology assessment of icon elements in a digital human-computer interface the modified sample-delay matching task experimental paradigm is used under different time pressures 4 000 and 2 000 ms and different icon quantities three five and ten icons on icon memory based on event-related potential ERP technology.Experimental results demonstrate that P300 has significant volatility changes and the maximum amplitude around the middle line of the parietal area PZ and P200 has obvious volatility changes around the middle line of the frontal and central area FCZ during icon cognition.P300 and P200 amplitudes increase as tasks become more difficult.Thus P300 latency is positively correlated with task difficulty. ERP research on the characteristics of icon memory will be an important reference standard in guiding user neurocognitive behavior and physiology assessment on interface usability.

Quantity of plant leaf area on three major public squares in Kunming City, China

Regressive formulae to calculate the quantity of plant leaf area for 13 species of ornamental plants were set up based on investigation data of 30 species on 3 major public squares (Dongfeng square, Shengli square and Guandu square) in Kun-ming City, China, which were applied to calculate quantities of plant leaf area of these 13 species. The quantities of plant leaf area for the other 17 ornamental plant species on these squares were directly measured, and the total quantity of plant leaf area of each studied square was obtained individually. The results showed that the quantity of plant leaf area on Shengli square with ornamental plants structure composed of arbor tree species, shrub tree species and turf grass was highest among the three squares. It is believed that the design model of multi-storied vertical structure and proper tending of plant community could not only increase the quantity of plant leaf area, but also play an important role in generating ecological and landscaping benefits. Some corresponding suggestions were put forward on the basis of comprehensive analyses on the plant leaf area quantity of the three representative squares in Kunming urban area.

基于深度学习的钻孔冲煤量智能识别方法

【目的】为解决人工统计钻孔冲煤量不准确以及效率低等问题,提出一种YOLOv8n、Res-Net34和PP-OCRv4算法相结合的智能识别方法。【方法】该方法首先使用YOLOv8n算法完成一级检测,同时并行级联ResNet34算法与PP-OCRv4算法进行二级处理,并结合基于追踪帧数的分类状态判别方法,建立了冲煤量自动计算的算法框架。其次,在YOLOv8n的C2f模块中引入可变形卷积DCNv2模块,以削弱点状强光照对特征采集的影响,并将其默认的检测头替换为Dynamic Head检测头模块,以强化算法在尺度,空间和通道维度的特征提取能力,以及将CIoU损失函数替换为SIoU损失函数,以加速预测框与真实框的匹配,并利用自建的数据集对改进后的YOLOv8n算法进行验证。【结果和结论】结果表明:(1)与原算法相比,平均类别检测精度提高了7.6%,召回率提高了3.5%,精确率提高了6.4%,验证了改进策略对提升模型性能的有效性和稳定性。(2)对4个不同的瓦斯抽采水力冲孔钻场的实时视频进行测试,识别准确率分别为100.0%、93.3%、95.7%和93.1%,平均达到95.5%,满足了水力冲孔钻孔冲煤量自动识别的精度要求。(3)采用追踪帧数确定ResNet34分类状态的方法,解决了分类状态单次识别结果不可靠的问题。研究成果为YOLO系列算法与其他深度学习技术的融合和广泛应用提供了技术与实践基础,对促进瓦斯抽采钻场等煤矿井下复杂场景的智能化进步具有参考价值。

Lie Symmetries and Conserved Quantities for the Singular Lagrange System

The invariance of the ordinary differential equations under the infinitesimal transformations was used to study the Lie symmetries and conserved quantities for the singular Lagrange system. The determining equations, the restriction equations of the Lie symmetries and the form of conserved quantities of the system are obtained.

Conserved quantities from Lie symmetries for nonholonomic systems

This paper presents a new method to seek the conserved quantity from a Lie symmetry without using either Lagrangians or Hamiltonians for nonholonomic systems. The differential equations of motion of the systems are established. The definition of the Lie symmetrical transformations of the systems is given, which only depends upon the infinitesimal transformations of groups for the generalized coordinates. The conserved quantity is directly constructed in terms of the Lie symmetry of the systems. The condition under which the Lie symmetry can lead to the conserved quantity and the form of the conserved quantity are obtained. Finally, an example is given to illustrate the application of the result.

Lie Symmetries and Conserved Quantities of Holonomic Mechanical Systems in Terms of Quasi-Coordinatee

Aim To study the Lie symmetries and conserved quantities of holonomic mechanical systems in terms of qnasi-coordinates. Methods The definition of an infinitesimal generator for the holonomic mechanical systems in terms of quasi-coordinates was given. Lie's method of the invariance of ordinary differential equations under infinitesimal transformations was used. Results and Conclusion The determining equations of the Lie symmetries of holonomic mechanical systems in terms of quassi-coordinates are established. The structure equation and the form of conserved quantities are obtained. An example to illustrate the applicaiton of the result is given.

Comparisons of Nectar Quantity and Sugar Concentration of Pomegranate Blossom in a Day

[Objective] The aim was to research the rules of nectar quantity and sugar concentration of perfect and staminate flowers in a day. [Method] Based on nine Tianguang Yan pomegranate trees, nectar quantity and sugar concentration of per- fect and staminate flowers were measured and analyzed in morning and afternoon. [Result] Average nectar quantity and sugar concentration differed insignificantly in morning and afternoon of perfect flowers, which could also be applied to staminate flowers. However, average nectar quantity of perfect flower was 64.09 μI and of staminate flower was 44.07 μl. It is obvious that the two were of extremely signifi- cant differences （t=4.642, P〈0.01）, and the former was significantly higher by 45,43%. On the other hand, average sugar concentration of perfect flower was 48.44% and of staminate flower was 37.16%. The two were of extremely significant differences and the former is higher by 30.36%, compared with the latter. These suggested that nectar quantity and sugar concentration would maintain unchanged in different periods for a day, if nectars are not consumed by pollinators, such as bees and butterflies. In the same period, nectar quantity and sugar concentration of per- fect flowers were higher than those of staminate flowers. [Conclusion] The research provides references for benefits increase of bee farmers and fruit farmers, as well as exploration of bee pollination.

微量润滑在机械加工中的应用研究进展

微量润滑(minimum quantity lubrication,MQL)被视为一种能够改善浇注式和干切削技术缺陷的绿色可持续加工技术,在机械加工领域应用越来越广泛。综述了微量润滑的基本原理及应用。首先,分析了微量润滑及其系统以及在车削、铣削、磨削、钻削加工中的性能表现,微量润滑在铣削SKD 61钢时,刀具侧面磨损能减少60%。其次,阐述了微量润滑的进展及分类,并详细分析了纳米流体微量润滑(nanofluid minimum quantity lubrication,NMQL)、低温微量润滑(cryogenic minimum quantity lubrication,CMQL)、多场赋能微量润滑的冷却润滑机理。结果表明,在磨削钛合金时,纳米流体静电雾化微量润滑相对于微量润滑,磨削温度降低了40%。在机械加工中,微量润滑提升了冷却润滑效果,降低了成本和切削液用量,并改善了表面粗糙度、切削力和刀具磨损等方面的加工性能。

Symmetries and conserved quantities of generalized Birkhoffian systems

Three kinds of symmetries and their corresponding conserved quantities of a generalized Birkhoffian system are studied. First, by using the invariance of the Pfaffian action under the infinitesimal transformations, the Noether theory of the generalized Birkhoffian system is established. Secondly, on the basis of the invariance of differential equations under infinitesimal transformations, the definition and the criterion of the Lie symmetry of the generalized Birkhoffian system are established, and the Hojman conserved quantity directly derived from the Lie symmetry of the system is given. Finally, by using the invariance that the dynamical functions in the differential equations of the motion of mechanical systems still satisfy the equations after undergoing the infinitesimal transformations, the definition and the criterion of the Mei symmetry of the generalized Birkhoffian system are presented, and the Mei conserved quantity directly derived from the Mei symmetry of the system is obtained. Some examples are given to illustrate the application of the results.

Effects of Different Land Use Patterns on Soil Microbial Quantity and Activity in Hongta District,Yuxi City

[Objective] This study aimed to investigate the effects of different land use patterns on soil ecological environment. [Method] Total three representative land use patterns （corn field, cherry tree land, wood land） were selected from Hongta District, Yuxi City, and under these three patterns, soil microbial quantity and activity were studied. [Result] Under the three land use patterns, soil microorganisms were domi- nated by bacteria; soil microbial quantity ranked as wood land＇s〉cheery tree land＇s〉 corn field＇s; and total microbial activity, catalase activity and urease activity all ranked as cherry tree land＇s〉wood land＇s〉corn field＇s. [Conclusion] Soil microbial activity and functions are related to farmland management measures, as well as land use pattern and soil nutrients.