Rolling bearing composite fault diagnosis method based on EEMD fusion feature

Aiming at the problem that the composite fault vibration signal of rolling bearing is complex and it is difficult to effectively extract the impact characteristics of the composite fault, a composite fault diagnosis method of rolling bearing based on multi-scale fuzzy entropy feature fusion is proposed. Compared with traditional fault feature extraction methods that can only extract single fault feature information, this method can increase the discrimination of composite fault features, effectively separate multiple composite fault features, and more comprehensively characterize composite fault feature information. First, the signal is processed by EEMD, getting a series of IMF components. Secondly, the energy and kurtosis index of the IMF component are calculated, the appropriate IMF component is selected through the correlation coefficient to obtain a new time series, the multi-scale fuzzy entropy is calculated, and feature fusion performed. Finally, the least square support vector machine is used to diagnose the fault of the fusion feature. The method is verified by a mechanical failure simulation test bench. The experimental results show that this method can quantitatively characterize the data information of fault signal, improve the anti-interference ability, have good feature extraction ability of composite fault of rolling bearings, and can effectively identify the type of composite fault. Compared with the method using multi-scale fuzzy entropy, energy and kurtosis index alone, the accuracy of fault diagnosis increases by 8.12 % and 11.65 %, respectively.

     

肯尼亚天然金红石矿流化床氯化率的研究

对肯尼亚金红石矿加碳氯化体系的热力学和动力学进行了研究,分析表明,C在固相中过量,体系处于平衡态时,TiCl4和CO是仅有的2个稳定的产物,增加C/TiO2比对产物组成影响不大;高温时,TiO2与C和Cl2生成CO的方程是占主导地位的。本实验提出了一个反应速率模型,得到金红石氯化率的公式,与实验数据吻合较好。反应速率与颗粒初始半径和天然金红石密度有关,在900℃到1000℃温度范围内,表观活化能为10.569 kJ/mol,扩散是反应的主要控制步骤。得到了C-Cl2体系中氯气反应率表达式,氯气反应率取决于反应程度、氯气浓度和焦炭粒径。     

以冶金渣为胶凝材料的全尾砂胶结充填料的制备

以矿渣-钢渣-脱硫石膏为胶结剂,以密云铁矿全尾砂为骨料,制备用于胶结充填采矿的充填材料。综合分析料浆流动度和胶结充填体试块强度,优化胶结充填料配比,并通过X射线衍射(XRD)和扫描电镜(SEM)微观分析观察其微观结构和水化产物。试验结果表明,当胶结剂中矿渣掺量为60%、脱硫石膏掺量为12%、钢渣掺量为28%、胶砂比为1∶4、充填料浆浓度为80%时,料浆适应膏体泵送的流动性要求,充填体28 d抗压强度为8.62 MPa,满足矿山充填强度要求。     

璀璨南方明珠——广东大峡谷

朋友因女儿考到理想学校去南华寺进香还愿,问我是否愿意同行,我本是好玩之人,连忙答应,并邀同事一起前行!在QQ上问广东摄影的朋友,哪里好玩,他们推荐了丹霞山,金鸡岭和广东大峡谷,查看地图,广东大峡谷离韶关不远,又是山里,应该比较安静,决定去广东大峡谷。于是朋友的还愿之行,成了我们的开心之旅!广东大峡谷位于乳源瑶族自治县西南68公里的大布镇。据专家考证:它是由于距今一亿三千万年前的喜马拉雅造山运动,地壳几度升沉,多期的花岗岩侵入,地层断裂,再经风化侵蚀和大约1000万年的洪水冲刷而形成的,是华南地区唯一的地陷式峡谷。     

Anisotropy oxidation of textured ZrB2–MoSi2 ceramics

Oxidation behavior of hot forged textured ZrB₂–20 vol% MoSi₂ ceramics with platelet ZrB₂ grains was investigated at 1500 °C for exposure time from 0.5 to 12 h. Compared to untextured ceramics, the textured ceramics showed obvious anisotropic oxidation behavior and the surface normal to the hot forging pressure demonstrated better oxidation resistance. Such improvement in the oxidation resistance is primarily considered as a higher intrinsic ZrB₂ atomic density on the orientated {0 0 l} planes in the textured ceramics. It is expectable that the anisotropic textured ZrB₂–MoSi₂ ceramics can offer better oxidation resistance when a certain surface with higher oxidation resistance is exposed to air at elevated temperature.     

高温气冷堆球形燃料元件中基体石墨杂质含量的研究

研究了高温气冷堆球形燃料元件的基体石墨及所使用的主要原材料中微量及痕量杂质元素的含量，利用等离子发射光谱仪对Ｂ、Ｌｉ、Ｆｅ、Ｔｉ、Ｕ、Ｔｈ、Ｇｄ、Ｅｕ、Ｓｍ、Ｄｙ等十几种重要元素进行了分析，并比较了加工处理过程对于杂质离子含量的影响。研究结果表明，在球形燃料元件制造过程中所使用的原材料及制成的基体石墨均符合球形燃料元件的设计指标。     

柠檬酸甘油单,二酸酯合成过程中沉淀物的分析

对柠檬酸和单甘酯酯化反应制取柠檬酸甘油单、二酸酯过程中产生的沉淀进行了红外光谱分析，并对沉淀产物的原因提出了合理的解析。     

榆林市煤炭生态补偿费征收与使用体制上的基本属性

榆林市煤炭资源生态补偿费征收与使用制度上的不完善,表现为相互联系、相互影响的基本属性.即征收主体与被征收主体的不完全市场性、央企与私企费负上的差异性、生产企业与当地居民生态环境保护行为的弱自律性、生态费征收与使用的事后性和低效性.     

Selective Adsorption of Adenosine and Guanosine by a β‐Cyclodextrin/Layered Double Hydroxide Intercalation Compound

A film of carboxymethyl‐β‐cyclodextrin‐intercalated Zn–Al layered double hydroxide (CMCD–LDH) was investigated for selective adsorption of the nucleosides adenosine (A) and guanosine (G). The effects of pH value and adsorption time on the adsorption behavior were studied. The CMCD–LDH film shows a higher selectivity for G than A under identical conditions of G and A, which results from the ability of selective recognition of the interlayer CMCD. The kinetic studies show that adsorption of A and G by the CMCD–LDH film can be described satisfactorily by the slab diffusion model. Both the values of diffusion coefficient (D) and adsorption capability (q_e) of G by the CMCD–LDH film are larger than those of A, demonstrating the selective adsorption of the CMCD–LDH film for nucleosides. Due to its easy preparation and manipulation, this film is expected to be successfully applied in the field of selective adsorption and separation.     

Degenerate problems of optimal control. II

The paper is the second part of the review of the results obtained by the special theory of the degenerate problems of optimal control and its applications, including the newest ones. Consideration was given to the methods based on the rearrangement of the degenerate problems in the smaller-order regular derivative problems, the main types of solutions of the derivative problems, and the issues of their realization as the generalized solutions of the original problems. The generalized conditions for their optimality were derived. Examples, both methodological and applied, were presented to demonstrate the efficiency of these methods.