Experimental determination of mechanical properties and short-time creep of AISI 304 stainless steel at elevated temperatures

The high temperature properties of AISI 304 stainless steel were studied. Basic data about the employed experimental equipment, testing procedures, and specimen geometry were given. The experimental setup was used to obtain stress-strain diagrams from tensile tests at room temperature as well as several elevated temperatures. Furthermore, the specimens were subjected to short-time creep tests at various temperatures. Stress levels for creep testing were established as a percentage of yield stress. The results indicate that at lowered temperatures and lower stress levels, AISI 304 stainless steel can be used as a sufficiently creep resistant material.

Investigation of the friction coefficient evolution and lubricant breakdown behaviour of AA7075 aluminium alloy forming processes at elevated temperatures

The lubricant behaviour at elevated temperatures was investigated by conducting pin-on-disc tests between P20 tool steel and AA7075 aluminium alloy. The effects of temperature, initial lubricant volume, contact pressure and sliding speed on the lubricant behaviour(i.e. evolutions of the coefficient of friction(COF) and the breakdown phenomenon) were experimentally studied. The evolutions of COF at elevated temperatures consisted of three distinct stages with different friction mechanisms. The first stage(stage Ⅰ) occurred with low friction when the boundary lubrication was present. The second stage(stage Ⅱ) was the transition process in which the COF rapidly increased as the lubricant film thickness decreased to a critical value. In the final plateau stage(stage Ⅲ), lubricant breakdown occurred and intimate contact at the interface led to high friction values. At the low friction stage(stage Ⅰ), the value of COF increased with increasing temperature. The increase in temperature, contact pressure and sliding speed as well as the decrease in initial lubricant volume accelerated the lubricant breakdown.

Elevated liver enzymes portends a higher rate of complication and death in SARS-CoV-2

BACKGROUND Severe acute respiratory syndrome coronavirus 2,or coronavirus disease-2019(COVID-19),has infected millions worldwide since its discovery in Wuhan,China in December 2019,but little is still known about the disease process.Preliminary research in China notes liver function tests(LFTs)abnormalities are common in COVID-19 patients,suggesting decreased hepatic function,and that abnormalities in LFTs are related to complicated disease course and negative outcomes.However,there has been limited large-scale data assessing COVID-19’s association with liver dysfunction and negative outcomes.AIM To investigate how COVID-19 affects the liver function and disease course in patients infected with the virus treated at Henry Ford Hospital from March to September 2020.METHODS A total of 8028 patients infected with COVID-19 were identified and included in the study at a single academic center.Data from medical charts on laboratory testing including aspartate aminotransferase(AST),alanine aminotransferase(ALT),alkaline phosphatase(AP),and bilirubin levels,past history of liver disease,and disease course indicators including hospital admission,intensive care unit(ICU)admission,intubation,and death were recorded and analyzed.Elevated liver enzymes were defined as ALT/AST greater than 60,AP greater than 150,or bilirubin greater than 1.5,super-elevated liver enzymes were defined as ALT/AST greater than 120,AP greater than 300,or bilirubin greater than 3.0.RESULTS A total of 8028 COVID-19 patients were identified and included in the study.Data from medical charts on LFTs(namely,AST,ALT,AP,and bilirubin levels),past history of liver disease,and disease course indicators(hospital/ICU admission,intubation,death)were recorded and analyzed.LFTs from 3937 patients were available for interpretation.45% were found to have elevated or super-elevated LFT.When compared to COVID-19 patients without elevated LFTs,this cohort was found to have significantly higher odds of hospital admittance,ICU admission,intubation,and death(all P<0.001).248(3.1%)had a history of liver disease.Those with elevated and super elevated LFTS had significantly higher odds of having a past history of liver disease(P<0.001).CONCLUSION The findings from this study suggest that in patients who have tested positive for COVID-19,those with elevated and super elevated liver enzyme levels have significantly higher odds of hospital admittance,ICU admittance,intubation and death in comparison to those COVID-19 patients without elevated liver enzyme levels.

Design of New Elevator Pressure Guide Plate and Its Test Device

Pressure guide plate plays a certain role in the safe operation of elevator.Based on understanding the respective performance of new and old pressure guide plates,this paper analyses the problems existing in the original pressure guide plate.It also conducts stress analysis according to the function of pressure guide plate on elevator,and designs a new type of pressure guide plate combined with technological capability and equipment.According to the stress characteristics,a test device is designed and a comparative test is made between the new type of pressure guide plate and the old in order to test the reliability of the new type of pressure guide plate.The test proves that the new pressure guide plate of elevator can meet the requirements of product use and safe operation of elevator products.

新型电梯钢丝绳张力检测设备研制

本文设计了一种以STM32L051为核心的新型电梯钢丝绳张力检测设备,包括整体结构、硬件结构和系统软件设计,该设备采用型号为LZ-WS6的S型传感器作为水平拉动钢丝绳时拉力传感器,同时将HX711模数转换芯片用于钢丝绳张力检测模块。该钢丝绳张力检测设备结构简单,操作便捷,能自动判断钢丝绳张力值是否符合要求,提高了电梯生产单位和检验检测单位对钢丝绳张力的检验检测效率。

电梯曳引轮的轮槽磨损原因及其检验

曳引轮轮槽在电梯运行过程中承受着巨大的压力和摩擦力。由于多种因素的影响,轮槽可能会出现磨损现象。这种磨损不仅会影响电梯的运行效率,严重时可能会出现钢丝绳打滑等危险情况。通过对轮槽磨损原因进行分析,并研究检验方法,可以及时发现问题并采取相应的措施,从而延长曳引轮的使用寿命,保障电梯的安全可靠运行。对电梯曳引轮的轮槽磨损原因及其检验进行了探讨,以供参考。

低顶岛式斜坡堤的堤顶高程设计方法

针对低顶岛式斜坡堤的堤顶高程确定方法,基于国内外现有研究成果和所依托的工程实践,探讨影响低顶岛式斜坡堤的堤顶高程设计关键因素,对强浪向分散、常浪向集中的情况提出堤顶高程宜使堤后次生波与非掩护浪向设计波浪基本相当的设计理念,并结合工程案例的物理模型试验结果进行对比分析。结果表明,所提出的设计理念合理、可行,对未来类似工程的设计具有借鉴和参考意义。

Clinical features and surgical treatment of double elevator palsy in young children

AIM： To describe the clinical features of congenital double elevator palsy（CDEP） and to evaluate various surgical outcomes between the standard Knapp and augmented Knapp procedures, based on improvements in primary eye position and ocular motility.METHODS： Twenty-two patients with CDEP at Shanghai Children＇s Hospital were enrolled from July 2014 to January 2018. The forced duction test（FDT） was negative in 21 patients, aged 8 mo to 12 y（mean 5.4 y）. Patients were divided into two treatment groups： 16 patients underwent the standard Knapp procedure（group A）, with or without horizontal squint procedure; and 5 patients underwent the augmented Knapp procedure（Foster procedure; group B）. One patient underwent inferior rectus recession in the affected eye and superior rectus recession in the sound eye because of a positive FDT. The pre-and postoperative vertical deviations in the primary position and ocular motility were compared in the two groups.RESULTS： Twenty-one eyes of the 22 patients（95%） were aligned within 10 prism diopters（PD）, and all patients（100%） reached ≥25% elevation improvement after surgery. The average corrected vertical deviation in group B was statistically better than that of group A. For group A, the vertical deviation in the primary position decreased from 24.75Δ±8.35Δ to 4.56Δ±8.07Δ after surgery, for an improvement of 23.06Δ±6.51Δ（P〈0.05）. In group B, the decrease was from 35.00Δ±5.00Δ（range 30Δ-40Δ） to 1.00Δ±2.24Δ, for an improvement of 34.00Δ±4.18Δ（P〈0.05）. There were significant differences between the pre-and postoperative elevation in each group（group A, P〈0.05; group B, P〈0.05）. The average scale of improved elevation in group B（1.80±0.45） was not significantly better than that of group A（1.69±0.87; Z=-0.732, P=0.548）. The average follow-up periods lasted 21 mo in group A and 18 mo in group B.CONCLUSION： For vertical deviations 〈30Δ, the standard Knapp procedure can be chosen. For deviations greater than 30Δ-40Δ, the Foster procedure should be chosen. Because of our early interference, the inferior rectus（IR） muscle did not show mechanical restriction. Monocular elevation deficiency（MED） should be diagnosed early so that complications will be reduced and the procedure will be easier for the surgeon.

Distribution Patterns of Medicinal Plants along an Elevational Gradient in Central Himalaya,Nepal

This study aimed to compare the distribution patterns and trends of plant parts used among different groups of medicinal plants, geographical regions,and between medicinal plants and all vascular plants.We used the published sources for elevation records of 2,331 medicinal plant species to interpolate presence between minimum and maximum elevations and estimated medicinal plant richness for each 100-m elevational band. Monte Carlo simulations were used to test whether differences in elevational distribution between different groups of medicinal plants were significant. Total number of medicinal plants as well as different groups showed unimodal relationship with elevation. The elevational distributions of medicinal plants significantly differ between regions and between medicinal plant groups.When comparing the richness of all medicinal plants to all vascular plants,Monte Carlo simulations indicated that the numbers of medicinal plants are higher than expected at low elevations.The highest richness of medicinal plants at low elevation could be possibly due to favorable environmental factors such as high temperature, rainfall,sunlight or due to higher density of human population and thus higher pressure on use of any plants in lower elevations.

Behavioral Characteristics of Pharmacologically Selected Lines of Rats: Relevance to Depression

This brief review discusses the behavioral consequences of two pharmacologically selected lines of rats. Flinders Sensitive (FSL) and Flinders Resistant (FRL) Lines of rats were selected on the basis of differential hypothermic and behavioral responses to the anticholinesterase, diisopropylfluorophosphate (DFP). FSL rats are more sensitive to the hypothermic effects of cholinergic, serotonergic, and dopaminergic agonists but less sensitive to the locomotor or stereotypic effects of dopamine agonists. FSL rats exhibit greater immobility in the forced swim test and reduced social interaction compared with FRL rats, but do not differ in saccharin intake, behavior in the elevated plus maze, or responses for rewarding brain self-stimulation. The exaggerated immobility and reduced social interaction are counteracted by chronic treatment with antidepressants. Because FSL rats were more sensitive to 5-HT1A receptor agonists, high (HDS) and low (LDS) 8-OH-DPATsensitive lines were selectively bred for differential hypothermic responses to the 5-HT1A receptor agonist, 8-hydroxy-2-(di-N-propylamino)tetralin (8-OH-DPAT). HDS rats were also more sensitive to the hypothermic effects of oxotremorine, a cholinergic agonist, but selection for this response did not diverge with later selection. HDS rats exhibited greater immobility in the forced swim test than LDS rats and this correlated response could be seen early in selection (generation 3). HDS rats also showed reduced social interaction compared to LDS rats, but did not differ in behavior in the elevated plus maze. These findings confirm that selection for hypothermic responses to pharmacological agents do have behavioral consequences, notably the production of depressive-like phenotypes, which can be counteracted by chronic antidepressant treatment. Because increased 5-HT1A receptor sensitivity was common to both selected lines (FSL and HDS), neurobiological processes dependent on this receptor could contribute to the abnormal behaviors that manifest in these rat lines and thus suggesting a mechanism underlying depressive behaviors in humans. However, available human data are inconsistent with this hypothesis and suggest that other mechanisms underlie these behavioral abnormalities in HDS and FSL rats. These mechanisms as well as additional behavioral testing in these rat lines will be discussed.

nNOS-CAPON偶联抑制剂的合成及抗焦虑研究

合成nNOS-CAPON偶联抑制剂并评价其抗焦虑作用。根据nNOS-CPAON蛋白结构域配体结合部位的结构特点设计并合成了一系列缬氨酸类化合物,通过评价化合物抑制nNOS-CAPON蛋白相互作用(PPI)的活性来筛选化合物,并通过高架十字迷宫实验验证其抗焦虑作用。设计并合成了两个系列共15个化合物,其中N-8具有较好的PPI抑制作用,且在高架十字迷宫实验中显著增加小鼠在开臂的停留时间,具有较强的抗焦虑作用。研究丰富了nNOS-CAPON偶联抑制剂的结构类型,并验证了该类型化合物的抗焦虑作用。

碳/碳复合材料高温动态拉伸试验技术研究

为了满足碳/碳复合材料和高温动态拉伸试验需求,将大电流加热装置应用于旋转盘式霍普金森拉杆装置,以实现试验所需高温环境加热试样,并辅以水冷装置构成升温系统,同时使用红外测温装置检测和采集系统温度,共同构建碳/碳复合材料的高温动态拉伸试验系统,并采用数值分析模拟不同试样参数对温度均匀性的影响,确定试样尺寸参数。基于所得系统获取了碳/碳复合材料在室温~1 300℃的高温动态拉伸应力-应变曲线。试验结果表明,随温度上升,试样的破坏应变和应力均呈下降趋势。建立的高温动态拉伸试验系统可为开展碳/碳复合材料高温动态拉伸力学性能提供试验技术支持。

基于模型实验的自升式网箱的水动力性能

为探究影响自升式网箱水动力因素,优化与改进网箱结构,减少极端作业环境下养殖鱼类损耗、提升网箱系统安全,本实验开展了自升式网箱及其配套支撑系统的水动力性能研究。通过物理模型实验探究了不同流速、不同迎流角度、不同下潜深度以及安装不同类型网衣等因素对钢结构自升式网箱受力的影响。结果显示,在网目尺寸、下潜深度与迎流角度相同时,自升式网箱整体受力与水流速度呈正相关性,网箱整体与水流方向垂直时,网箱的受力最小,且网箱迎流角度在30°~60°时可能会受到最大的冲击力;模型网箱在距水底50 cm时的受力大于网箱距水底80 cm时的受力;UHMWPE网衣受力比相同线面积的PET网衣更大。研究表明,在网箱设计时可以优先选择六角形网目PET网衣,而附着物可使得网衣的受力增加至原来的10倍以上,建议在网箱结构设计时要充分考虑附着物对网箱结构强度的影响。本研究可对自升式网箱的设计、布置及网衣选择提供参考。自升式网箱作为一种深远海养殖装备,其前景非常广阔,但相关工作任重道远。

电梯节能增效意义及能效测试技术分析

以“双碳”目标为指引,受环境保护、降本增效等因素影响,各大电梯生产及使用企业对电梯能效测试技术的需求越来越高。在此背景下,该文从政策、标准以及技术3个方面分析电梯节能增效的必要性;介绍驱动和控制系统、能量回馈装置等电梯能效影响因素;归纳电梯能效测试方法,并引入一则电梯能效测试实例对比测试结果;最后从测试方法标准化和监测产品智能化两方面提出电梯能效测试技术发展方向。研究表明:能效测试是当前国内外电梯能效优化的基础;空载法测试效率更高,需优化载荷系数动态取值方案提高结果准确度;在线监测技术应用比较缺乏。

基于深度学习的电梯层门安全检测关键技术研究

通过深度学习进行小目标检测,提出了可以在电梯正常运行情况下,对电梯层门关键部件的异常状态进行检测分析判断的一种新型的检测电梯层门关键部件的检测方法。为了对本文设计的电梯层门关键部件检测分析设备进行验证,本文搭建了电梯层门关键部件检测分析实验平台。通过现场验证,该系统实现了对在用电梯的电梯层门关键部件检测分析等功能。

Comprehensive Assessment of Anxiolytic Properties in 4-HPAA Derivatives: Bridging in Vivo Validation and Molecular Docking Analyses

Anxiety is a significant mental health issue that substantially affects an individual’s quality of life. Feelings of uneasiness, irritability, and sleep disturbances characterize it. 4-Hydroxyphenyl acetic acid (4-HPAA) is identified in brain cells as a physiological byproduct of tyramine. This study hypothesizes that 4-HPAA may regulate anxiety due to its anxiolytic properties, acting as a modulator of the GABAergic system, which plays a crucial role in the pathophysiology of anxiety disorders. Our study aims to enhance the anxiolytic effects of 4-HPAA through chemical modification to improve its pharmacokinetic properties. Three derivatives, namely Isopropyl-4-hydroxy-[phenyl] acetate (IHPA), Isopropyl-4-hydroxy-[phenyl] acetate (MPAA), and 4-methoxyphenyl acetate (MPHA), have been synthesized from 4-HPAA. This assessment will use well-established animal models, specifically the Elevated Plus-Maze (EPM) and Zero Maze (EZM) tests, selected for their validity in replicating anxiety-like symptoms in animals. Chronic caffeine administration via drinking water (0.3 g/l for 14 days) was employed to induce an anxiety state for testing purposes. IHPA and MPAA demonstrated significant anxiolyticactivity when tested in the EPM and EZM experiments. Molecular docking simulations using AutoDock Vina indicated that 4-HPAA derivatives had docking scores ranging from −5.8 to −4.8 kcal/mol, compared to the standard anxiolytic medication Diazepam, which scored −7.1 kcal/mol. These scores suggest a potential for 4-HPAA derivatives to interact effectively with the Gamma-aminobutyric acid (GABA_A) receptor. In conclusion, our in vivo and in silico analyses indicate a promising anxiolytic potential for 4-HPAA derivatives.

自动烟架提升机的结构优化设计与试验研究

文章针对目前烟叶烘烤前的上架过程依靠人工,存在危险性大、效率低、成本高的问题,以实用性和经济性为目标,通过对现有烤房进行改造,设计了一种自动烟架提升机。所设计的自动烟架提升机由可移动烟架、支撑立柱、电机、滑轮组等组成,通过滑轮机构实现烟架的平稳上升,并在ANSYS仿真软件中对提升烟竿装置进行应力仿真分析验证其可行性。该提升机在福建省永安烟草种植基地烤烟房进行了样机试制和装烟烤烟试验,试验效果达到预期目标,验证了该装置的有效性。

电梯制动器故障分析及其检验检测研究

为实现对电梯运行状态的实时监测,增强其故障分析和检验检测工作的针对性,提高电梯运行的安全性,在介绍几种常见电梯制动器结构和电气原理的基础上,列举电梯制动器的常见故障形式,包括控制故障、制动器磨损、弹簧压力不均和电磁线圈铁心故障等。之后提出一种基于信息采集的故障预判系统,利用物联网和数据分析手段,实现对电梯制动器故障的精准预判,更为合理地安排维保周期。最后,从功能性检验和电气系统检验两方面重点阐述电梯制动器检验检测的相关要求及关注重点,并提出相应的制动器安全防护措施,包括提高检验检测质量、强化制动器维修养护等。以期为电梯制动器的运行监管、维修养护和检验检测提供有力的技术支持,确保电梯的安全、可靠运行。

Anti-anxiety activity of successive extracts of angelica archangelica linn.on the elevated t-maze and forced swimming tests in rats

OBJECTIVE:Angelica archangelica Linn.is widely used in food and liquor preparations and also in Kashmiri folk medicine to reduce anxiety.We evaluated the anxiolytic effect of successive extracts of A.archangelica linn.(SAE) on rats tested in the elevated T-maze test(an animal model of generalized anxiety) at doses that exhibit antidepressant-like activity in humans.METHODS:A.archangelica(1 kg) was subjected to successive extraction in a soxhlet apparatus with solvents [petroleum ether(40-60℃),chloroform,ethyl acetate,methanol and decoction with water] in order of increasing polarity(yield:6.9%,7.3%,5.1%,11.88% and 8.2% w/w,respectively).SAE were evaluated for anxiolytic effects using the elevated T-maze and forced swimming tests in rats.RESULTS:Oral dosing of diazepam(1 mg/kg) and extracts(50,100 and 200 mg/kg) clearly showed an anxiolytic-like profile in the elevated T-maze test:it increased one-way escape and decreased inhibitory avoidance on the first,third and seventh day.In the forced swimming test,imipramine and SAE showed antidepressant-and anxiolytic-like effects as reflected by increased climbing time,swimming time and decreased immobility time on the first,third and seventh day.Aqueous and methanol extracts showed the most,petroleum ether(40-60℃) and chloroform intermediate,and ethyl acetate the least anxiolytic activity(*P<0.05,**P<0.01,***P< 0.001) in both models.CONCLUSIONS:These results suggest the anti-anxiety activity of various extracts of A.archangelica and strongly justify its use in traditional Indian medicine for the treatment of anxiety.

电梯安全性能的影响因素与检测技术分析

阐述电梯安全性能的影响因素,分析电梯检验检测中的问题及原因,提出强化策略,包括规范电梯检验程序和方法、统一操作流程和评估指标、完善电梯检验监管机制和责任分配。