自修复添加剂及在润滑脂中的应用

探讨了自修复添加剂在润滑脂中的应用,以寻求延长轴承使用寿命的新途径。

微米铜在润滑脂中自修复性能的评价

通过四球试验评价了微米铜在润滑脂中的自修复作用。结果表明:在适当的摩擦条件下,微米铜在摩擦表面沉积并与基体金属及磨损微粒熔合,重新组合为共晶焊接在摩擦表面上,形成自修复膜,使磨损得到补偿。

水基金属加工液润滑添加剂的使用

水基润滑添加剂的选用不仅要满足金属加工的要求,还必须与金属加工液的其他组分相容,避免对人体健康和环境造成危害。

齿形联轴器润滑脂台架试验的研究

研究了一种评价齿形联轴器润滑脂性能的台架试验方法,该方法解决了评定齿形联轴器润滑脂性能的问题。

水溶性润滑添加剂的现状和发展

从分子设计和纳米技术方面介绍了水溶性润滑添加剂的现状和发展,建议加强对水溶性润滑添加剂的研究。

合成长寿型金属加工液

用水溶性聚醚研制的合成长寿型金属加工液的性能达到了GB6144-85标准,单机使用周期超过1年,可替代进口磨削液使用。

Microstructure, mechanical and corrosion properties of magnesium alloy bone plate treated by high-energy shot peening

To enhance the mechanical properties and corrosion resistance of magnesium alloys,high-energy shot peening(HESP)was used.According to the results,the in-situ surface nanocrystallization(ISNC)microstructure was fabricated on the magnesium alloy surface,and its formation mechanism was the coordination among twins,dislocations,subgrain boundary formation and dynamic recrystallization.Under the released surface stress of sample,the residual compressive stress and microhardness rose,thus enhancing compactness of the surface passivation film Mg(OH)2.Besides,the corrosion rate dropped by 29.2% in maximum.In the polarization curve,the maximum positive shift of the corrosion potential of sample was 203 mV, and the corrosion current density decreased by 31.25% in maximum.Moreover,the compression resistance and bending resistance of the bone plate were enhanced,and the maximum improvement rates were 18.2% and 23.1%,respectively.Accordingly,HESP significantly enhanced mechanical properties and corrosion resistance of magnesium alloys.

Coupled cobalt-doped molybdenum carbide@N-doped carbon nanosheets/nanotubes supported on nickel foam as a binder-free electrode for overall water splitting

In an attempt to develop low-cost,non-noble-metal bifunctional electrocatalysts for water electrolysis in alkaline media,cobalt-doped molybdenum carbide@N-doped carbon nanosheets/nanotubes were fabricated by using C3N4 as the carbon source on a 3D porous nickel foam substrate.Benefiting from the optimized electronic structure and enhanced mass and charge transport,as well as the 3D conducting pathway,MoxCoy@N-CNSs/CNTs shows superior performance towards both the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)in an alkaline medium.The optimal electrocatalyst is Mo2Co1@N-CNSs/CNTs,which reveals a current density of 10 mA cm^-2 at the low overpotentials of 99 mV and 300 mV for the HER and OER,respectively,and a relatively low cell voltage(1.63 V)for the overall water electrolysis.The method of optimizing the composition and nanostructure of a material provides a new avenue for the development and utilization of high-performance electrocatalysts.

Propagation velocity measurement for flame of gas explosion in horizontal tube

In coal industry,gas explosion accidents emerge constantly,causing enormous casualties and poorer material property.In the course of studying gas exploding mechanism,the propagation velocity of the flame wave front is one of the most important factors.A set of flame velocity measuring system was designed according to the horizontal pipelined experimental facility of North University of China to study the effects of the quantity and blockage ratio of the circle ring obstacle on the flame propagation velocity in the inclosed tube.The research results show that the obstacle has obviously accelerating effect on the flame wave of gas explosion With the increase of quantity and blockage ratio of the obstacle,the flame accelerating effect becomes more obvious and the flame accelerating persistence is intenser,of which the effect of the quantity of the obstacle on the flame accelerating persistence is larger,but the effect of the blockage ratio of the obstacle on the flame accelerating persistenceis not obvious.

A new variable step-size LMS method and its application in DOA estimation of OFDMA signals

To meet the requirements of quick positioning of mobile terminals from base stations(BSs)or third-party devices,as well as to improve the convergence speed and reduce the steady state maladjustment of the least mean square(LMS)method,a new logarithmic-sigmoid variable step-size LMS(LG-SVSLMS)was proposed and applied to estimate the direction of arrival(DOA)of orthogonal frequency division multiple access(OFDMA)signals.Based on the proposed LG-SVSLMS,a non-blind DOA estimation system for OFDMA signals was constructed.The proposed LG-SVSLMS adopts a new multi-parameter step-size update function which combines the sigmoid function and the logarithmic function.It controls the adjustment magnitude of step-size during the initial and steady state phases of the LMS method to achieve both a high convergence speed and low steady state maladjustment.Finally,simulation was conducted to verify the performance of the LG-SVSLMS.The simulation results show that the non-blind DOA estimation system based on the LG-SVSLMS can accurately estimate the DOA of the target signal in the scenario where interference signals from multi-source and multi-path fading signals arrive at the third-party devices asynchronously with the target signal,and the estimation deviation is within±3°.The non-blind DOA estimation for OFDMA signals with the proposed LG-SVSLMS is of great significance for the instant positioning technology of mobile terminals based on the adaptive antenna array.

Suppression effect of solid inertants on coal dust explosion

The effect of solid inertants like rock dust on explosion suppression was experimentally tested.By adding solid inertants with different concentrations into three kinds of coal dust,the maximum explosion pressure P max and the rate of explosion pressure rise(d p/d t)max were acquired.Based on this,the suppression effect of rock dust on coal dust explosion was analyzed.The experimental and analytical results show that there are two major factors that play an important role in explosion suppression:composition of solid inertant and particle size of solid inertant.The higher the concentration of solid inertant and the smaller the particle size of solid inertant,the better the suppression effect.In addition,the smaller the particle size of coal dust,the larger the amount of rock dust.

Concept and evaluation method of equipment system of systems contribution rate

To scientifically evaluate the equipment system of systems(SoS)contribution rate,a contribution rate calculation method based on a structural equation model(SEM)is proposed in this paper.The connotation and evaluation process of the equipment SoS contribution rate were redefined and standardized.To solve the existing problems in the application of the original contribution rate formula,a modified contribution rate calculation formula is proposed.Finally,the contribution rate evaluation index was divided into latent and explicit variables.The measurement and structural equations in the SEM were used to calculate and analyze the latent variables.The simulation results show that the number of defense lines of air defense weapon equipment has a greater impact on the linear configuration than the group configuration.When the number of K-type air defense weapons is sufficient,the two-layer linear configuration should be adopted with 20 air defense weapon systems.When the number of K-type air defense weapons is insufficient,the single-layer group configuration should be adopted with 12 air defense weapon systems.

Effect of particle size of coal dust on explosion pressure

The effect of the particle size of coal dust on explosion pressure and the rising rate of explosion pressure is studied. Three coal dusts from Lingan Coal Mine in Canada and Datong Coal Mine in China are selected to test. The influence of particle size on the maximum explosion pressure P max and maximum pressure rising rate (d p /d t ) max of each coal dust was tested experimentally. The results indicate that with the decrease of particle size of coal dusts, explosion pressure increases on condition of the same concentration. If the concentration of coal dust is different, the maximum explosion pressure appears at the concentration of 500 g/m^3. The smaller the particle size of coal dusts, the larger the rising rate of explosion pressure of coal dust. When the concentration of coal dust is 500 g/m^3, the rising rate of explosion pressure of each coal dust is the maximum.

舰用油料快速检测技术进展

简要介绍了舰用油料快速检测技术及仪器的研究进展,对我军油料快速检测提出了建议。

Packaging category and its influencing factors of potassium nitrate

To understand the combustion characteristics of potassium nitrate and evaluate the magnitude of combustion risk, ox-idation solid test apparatus is used and the updated experimental criterion of the United Nations is adopted to measure the pack-aging category of potassium nitrate. The new criterion puts calcium peroxide and microcrystalline cellulose as references and burning rate as evaluation index. Effects of mixing ratio and insert medium on burning rate are reached. Test results show that pure potassium nitrate doesn＇t burn under normal temperature and pressure, however, its oxidation is very strong and the packaging category should choose the class I. As the mass fraction of potassium nitrate reduces, the burning rate first increases and then decreases. When the ratio is 2 ： 1,the combustion rate reaches the maximum, and the effect of combustion is the best. When 1 ： 3, the combustion rate is the minimum. The mixture combustion can be suppressed by silicon dioxide and hy-drogen phosphate, which is not fired when silica concentration is 40% or ammonium hydrogen potassium phosphate is 55%, their effects are very obvious.

Experimental study on explosion limit of M15 methanol-gasoline mixture

The explosion characteristics of M15 methanol-gasoline mixture was experimental test by using FRTA explosion limit instrument.The effect of temperature on the explosion area of the sample was studied.The results show that the lower explosion limit of M15 methanol-gasoline mixture is 1.716%and the upper explosion limit is 11.451%at the initial temperature of 80℃.The lower explosion limit of M15 methanol-gasoline is in the range of 1.711%-1.760%with the initial temperature from 25℃to 100℃,and the upper explosion limit of the sample changes between 11.253%and 11.451%.Considering experimental error and precision,it can be approximated that the temperature has little influence on the explosion area of M15 methanol-gasoline mixture.

硼酸酯摩擦化学反应的热力学分析

在高温高压下,硼酸三丙酯具有极压抗磨性能,从热力学的角度分析了硼酸三丙酯在摩擦界面发生的摩擦化学反应。

DGMI alleviates OGD/R-induced cell injury by regulating inflammatory and apoptosis signaling pathways

Diterpene ginkgolides meglumine injection(DGMI),a kind of Ginkgo biloba special extract injection,is now used for the treatment of ischemic stroke in convalescence.In the present study,we aimed to confirm whether DGMI could suppress inflammatory responses and apoptosis and explore the potential mechanisms underlying these effects.Cell viability and lactate dehydrogenase(LDH)release were measured by MTS and LDH assays after the cells were exposed to oxygen-glucose deprivation/reoxygenation(OGD/R).The extent of anti-apoptotic effect of DGMI was detected by flow cytometry using Annexin V-FITC/PI double staining assay kit.Pro-inflammatory cytokines,including TNF-α,IL-1β,IL-6 and IL-10,were quantified by a specific Bio-Plex ProTM Reagent Kit.Additionally,activities of TLR2/4,NF-κB p65,MAPK pathway and apoptosis-related proteins as well as cellular localization of NF-κB p65 were determined by Western blotting analysis and immunofluorescence staining,respectively.DGMI at 50μg/mL significantly increased the cell viability and decreased the secretion of IL-1β,IL-6,IL-10 and TNF-αin OGD/R-induced BV2 microglia cells.These effects were also confirmed by LDH assay and Annexin V-FITC/PI staining.Meanwhile,DGMI not only inhibited the protein expressions of TLR2,TLR4,MyD88,p-TAK1,p-IkBα,p-IKKβand Bak,but also decreased the cleaved caspase-3/caspase-3,Bax/Bcl-2 and cleaved PARP-1/PARP-1 ratio in OGD/R-induced BV2 microglia cells.Furthermore,OGD/R-enhanced p-JNK1/2 and p-p38 MAPK expressions and nuclear translocation of NF-κB p65 were also partially inhibited by DGMI.The present study showed that inflammatory responses were triggered in BV2 microglia cells activated by OGD/R,leading to the release of pro-inflammatory cytokines and apoptosis.DGMI suppressed the inflammatory response and apoptosis by regulating the TLR/MyD88/NF-κB signaling pathways and down-regulation of p-JNK1/2 and p-p38 MAPK activation.

Observation of clinical therapeutic effect of different techniques of acupotomy on coracoid pain of frozen shoulder

Objective:To explore the manipulation techniques of acupotomy in treatment of coracoid pain of frozen shoulder.Methods:A total of 60 patients with coracoid pain of frozen shoulder were collected.The randomized double-blind controlled method was adopted.Using random number table,the patients were divided into two groups,named a treatment group and a control group,30 cases in each one.In the treatment group,the pricking technique of acupotomy was adopted.In the control group,the traditional dissection technique of acupotomy was used.The duration of treatment was 5 weeks.Acupotomy was given once a week.At the end of treatment,pain index(visual analogy scale,VAS)and the therapeutic effect index were used to evaluate the therapeutic effect.Results:Before treatment,the average VAS score was 8.31±0.84 in the treatment group and it was 8.14±0.24 in the control group.After treatment,the average VAS score was 0.01±0.89 in the treatment group and it was 0.10±1.01 in the control group.The difference was significant before and after treatment in the patients of the two group(both P<0.05).The difference before and after treatment was not significant between the two groups.The effective rate was 100%and the remarkably effective rate was100%in either the treatment group or the control group.Conclusion:The pricking technique of acupotomy achieves the same therapeutic effect on coracoid pain of frozen shoulder as compared with the dissection technique,which suggests that the dissection technique is not the indispensable manipulation in the treatment of the disease.The pricking technique of acupotomy brings a smaller wound,less medical damage in,less suffering in patients and quicker recovery of wound,as well as quicker remission of pain after acupotomy.Such modified method of acupotomy is more significant in practice.However,a further research is suggested for the pathological mechanism of frozen shoulder.

Dexamethasone up-regulates TNFAIP3 to attenuate inflammatory response with smoke inhalation-induced acute lung injury based on the GEO database

To explore the protective effect of dexamethasone(Dex)on early inflammation in mice with smoke inhalation-induced acute lung injury(SI-ALI),we screened and analyzed bioinformatics gene chip data,followed by laboratory verification.The GEO database was used to search the ALI gene datasets,which were processed by the GEO2R online tool.The differential genes of each dataset were analyzed by Venn diagram to select the differential genes.A protein-protein interaction network was built on the String platform,and key protein modules were screened with Cytoscape software.The online databases DAVID and KOBAS were used for GO and KEGG enrichment analyses.A total of 45 C57BL/6 mice were randomly divided into three groups as follows:control group,smoke inhalation group(smoke group),and smoke inhalation+Dex group(smoke+Dex group),with 15 in each group.Inhalation of smoke for 10 min caused SI-ALI in the smoke group and smoke+Dex group,and the air was given in the control group.Dex(0.4 mg/100 g)was injected in the smoke+Dex group.Animals were sacrificed 24 h later,the bronchoalveolar lavage fluid(BALF)of the left lung was collected,and the levels of IL-1βand IL-6 were detected by ELISA.The expressions of mitogen-activated protein kinase kinase kinase 8(MAP3K8)and tumor necrosis factor-alpha-induced protein 3(TNFAIP3)in the right middle lobe were measured by real-time fluorescent quantitative PCR.GSE1871,GSE2411,and GSE17355 gene datasets were included,and 60 differential genes were selected.The key modules mainly included IL-6,IL-1β,MAP3K8,and TNFAIP3.The biological process of GO was mainly concentrated in inflammation,immune response,and so on.Cell components were mainly concentrated in extracellular and molecular functions.KEGG was mainly concentrated in TNF,Toll-like receptors,and NOD-like receptor signaling pathways.Compared with the control group,the levels of IL-1βand IL-6 in BALF in the smoke group and smoke+Dex group were significantly increased(all P<0.05),and the levels of IL-1βand IL-6 in the smoke+Dex group were lower compared with the smoke group(all P<0.05).Compared with the control group,the expressions of TNFAIP3 and MAP3K8 in the smoke group and smoke+Dex group were increased significantly(all P<0.05),and the expression of TNFAIP3 in the smoke+Dex group was increased compared with the smoke group(t=5.701,P<0.01).Moreover,the expression of MAP3K8 was decreased(t=13.49,P<0.01).It could be concluded that inflammation signal pathways in lung tissues of SI-ALI mice were activated,the secretion of IL-1βand IL-6 was increased,and the expressions of MAP3K8 and TNFAIP3 were increased.Application of Dex could up-regulate TNFAIP3,down-regulate MAP3K8,and decrease the secretion of IL-1βand IL-6.Dex might inhibit MAP3K8 by up-regulating TNFAIP3,thereby negatively regulating the TNF/MAPK signaling pathway to reduce the inflammatory response of SI-ALI.