液压减振器偏摩现象动力学分析和试验研究

通过对轿车后悬架系统力学建模,推导了双筒液压减振器在车轮平面和车轴平面内的受力计算公式,结合试验数据和实际参数对后悬架进行受力分析。从试验和系统动力学角度分析了液压减振器出现偏摩现象的原因。道路不平、车速较高并且冲击过大,使后减振器活塞杆承受突加弯曲,冲击载荷急剧增大,是导致偏磨的主要原因。车辆装配后,后减振器活塞杆不是严格垂直,使减振器活塞杆上产生附加动载荷,也易导致偏摩现象发生。所述的理论与试验研究结果可为减振器的设计及改进提供系统的理论依据。

车辆减振器活塞杆偏摩现象的疲劳分析

车辆在行驶中,减振器活塞杆不仅承受随机交变的轴向力的作用,而且承受交变的侧向力作用,在此情况下极易发生弯曲疲劳破坏,即偏摩现象。通过对前悬架系统力学建模,分析了减振器和活塞杆在车轮平面和车轴平面内的受力情况,采用Workbench软件对活塞杆在偏摩下进行应力计算,并利用S-N曲线和Goodman修正理论分析不同载荷状况下活塞杆疲劳寿命,试验结果表明,疲劳破坏部位发生在活塞杆中部焊接挡圈部位,这与实际中活塞杆易出现的失效的部位相吻合。

四点紧凑型制动夹钳单元防偏摩机构的设计研究

文章介绍了四点紧凑型制动夹钳单元几种防偏摩机构的结构原理,论述了制动夹钳单元防偏摩机构的设计、运动分析等关键技术。根据制动夹钳单元的具体使用车型,通过几种方案的对比,选择适用的防偏摩机构。

四川安岳南薰偏菩萨北宋摩崖造像调查与分析

安岳南薰偏菩萨摩崖造像共有四龛,其中2号龛开凿于北宋大中祥符六年(1013),雕刻千手观音与僧伽变相,反映观音以千手护持众生、以化身救苦济难的信仰观念,这种造像组合形式前所未见,也是所知唯一北宋僧伽变相实例。3号龛开凿于北宋熙宁二年(1069),系施主曹氏为完成亡祖亡父心愿而造,雕刻有上下五代家族供养人像,是宋人重视孝道与家族观念的产物,此龛像是川东文氏石匠早期造像遗存。

压气机转子叶片叶根断裂故障分析

针对某型燃气轮机磨合试车过程中出现的压气机转子叶片叶根断裂故障,利用故障树的排查方法,从材料、设计、工艺、冶金、实物加工、装配、使用等方面进行了详细的排查,对测量数据进行了深入分析,明确了转、静子碰摩是故障发生的主要原因,转、静子不同心导致涂层和蜂窝发生偏摩,以及转子叶片根部的加工痕迹明显促进了故障的发生。针对故障原因,提出了控制装配和叶片加工质量、改进磨合程序、加强叶片检查的改进措施,使故障得以解决。

Relationship between partial and average atomic volumes of components in Au-Ni alloys

In the framework of systematic science of alloys,the average molar property（volume and potential energy） functions of disordered alloys were established.From these functions,the average molar property functions,partial molar property functions,derivative functions with respect to composition,general equation of relationship between partial and average molar properties of components,difference equation and constraining equation of different values between partial and average molar properties,as well as general Gibbs-Duhem formula were derived.It was proved that the partial molar properties calculated from various combinative functions of average molar properties of alloys are equal,but in general,the partial molar properties are not equal to the average molar properties of a given component.This means that the partial molar properties cannot represent the corresponding properties of the component.All the equations and functions established in this work were proved to be correct by calculating the results of partial and average atomic volumes of components as well as average atomic volumes of alloys in the Au-Ni system.

Effect of Temperature on Volumetric and Viscometric Properties of Homologous Amino Acids in Aqueous Solutions of Metformin Hydrochloride

Density（ρ）and viscosity（η）are measured for glycine,DL-α-alanine DL-α-valine,and DL-α-leucine in 0.05,0.10,0.15 and 0.20 mol·L^-1aqueous metformin hydrochloride at 308.15,313.15 and 318.15 K.The measured values are used to estimate some important parameters,such as partial molal volume Vφ,standard partial molal volume Vφ^0,transfer volume ΔVφ^0,hydration number nH,the second derivative of infinite dilution of partial molal volume with respect to temperature,viz., ^2 Vφ^0 /T^2,viscosity B-coefficient,variation of B with temperature,viz., dB/dT,free energy of activation per mole of solvent Δμ1^＊0 and solute Δμ2^0＊ of the amino acids.These parameters are interpreted in terms of solute-solute and solute-solvent interactions and structure making/breaking ability of solutes in the given solution.In addition,Vφ^0,0 ΔVφ^0,viscosity B-coefficient,ΔB and Δμ2 ^0＊ are split into group contributions（NH3^＋ COO ^-）and -CH2 of the amino acids using their linear correlation and their behavior is discussed.

Metallurgical behavior and variation of vibro-acoustic signal during preheating assisted friction stir welding between AA6061-T6 and AA7075-T651 alloys

The present work investigated the effects of pin profiles(cylindrical and square),pin eccentricity(0.5 mm and 1 mm)in cylindrical tool and preheating(secondary heating)on metallurgical behavior,variation of vibro-acoustic signal pattern and joint strength during friction stir welding(FSW)between AA6061-T6 and AA7075-T651 alloys.The eccentric tool pins were observed to provide good flowability and intermixing between dissimilar metals,increased the size of stir zone,and the grains in stir zone were sufficiently finer with eccentric tool pin than concentric pin.The magnitude of vibro-acoustic signal increased when shoulder plunging started and drop in signal was noted when the tool shoulder reached its desired depth.The signal magnitude was noted to be higher in welding stage compared to tool plunging stage as the tool took in fresh material during tool movement along the weld path.Preheating the workpiece prior to pin plunging and during welding notably influenced the flow behavior and mixing pattern,and the grains in stir zone were slightly coarser than those in specimen without preheating.Significant reduction in the magnitude of the signal was also observed after preheating.Tensile and flexural strength of joints were also improved slightly when additional heating was employed.

Therapeutic effect of acupuncture and massage for shoulder-hand syndrome in hemiplegia patients:a clinical two-center randomized controlled trial

OBJECTIVE:To evaluate the therapeutic effects of acupuncture and massage for shoulder-hand syndrome in hemiplegia patients.METHODS:One hundred and twenty hemiplegia patients with stage I shoulder-hand syndrome were randomly divided into a group treated with standardized electric acupuncture and massage,and a group treated with rehabilitation therapy for 6 weeks.The primary indices evaluated were pain on passive movement of the shoulder using the numeric pain rating scale(NPRS),and the number of patients with shoulder-hand syndrome at Steinbrocker stage II or III after treatment.The secondary indices were Fugl-Meyer evaluation of functional movement of the upper limb and hand using the modified rankin scale(MRS).RESULTS:At post-treatment evaluation and a 12-week follow-up visit,NPRS score,number of patients with stage II or III shoulder-hand syndrome,and MRS score were all improved in the acupuncture-massage group compared with the rehabilitation group(P<0.05).On Fugl-Meyer evaluation,functional movement of the upper limb was also improved in the acupuncture-massage group compared with the rehabilitation group(P<0.05).CONCLUSION:Standardized acupuncture-massage therapy may have curative effects on shoulder-hand syndrome in hemiplegia patients.

Therapeutic Effect Observation on Combining Electroacupuncture and Tuina for Migraine

Objective: To observe the clinical effect of combining electroacupuncture and local tuina for migraine. Methods: A total of 94 migraine cases were randomly allocated into an observation group and a medication group, 48 cases in each group. Electroacupuncture and local tuina were used for cases in the observation group, whereas oral Flunarizine Hydrochloride capsules were used for cases in the medication group. Then the frequency of attacks, severity of the pain, duration of the headache, and associated symptoms of headache before and after treatment in the two groups were observed and compared. Results: The total effective rate in the observation group was 93.8%, versus 63.0% in the medication group, showing a statistical significant difference(P < 0.05). There were statistical significant differences in frequency of attacks, severity of the pain, duration of the headache and associated symptoms between the two groups(P<0.05). In addition, there were statistical significant differences in relapse rates after 4 and 8 weeks of treatment(P<0.05). Conclusion: Combining electroacupuncture and local tuina can obtain better effect and lower relapse rate than oral Flunarizine Hydrochloride capsules in migraine patients.

Applying tuina to exterior-interiorly connected meridians for post-stroke upper limb spasticity

Objective： To observe the effect of applying tuina to exterior-interiorly connected meridians for post-stroke upper limb spasticity. Methods： A total of 150 patients with post-stroke upper limb spasticity were randomly allocated into a treatment group （n=75） and a control group （n=75） by the random number table. Patients in the treatment group received tuina on exterior-interiorly connected meridians, whereas patients in the control group received standard rehabilitation therapy. The therapeutic efficacies in both groups were observed after 3 weeks of treatment. Results： The total effective rate in the treatment group was 89.3%, versus 61.3% in the control group, showing a statistically significant difference （P〈0.05）. After the treatment, the muscle tones by the modified Ashworth scale （MAS） were significantly improved in both groups （both P〈0.05）; and the improvement of muscle tone was more significant in the treatment group than that in the control group （P〈0.05）. Conclusion： Applying tuina to exterior-interiorly connected meridians can obtain an exact efficacy for post-stroke upper limb spasticity.

Effects of feet reflexology versus segmental massage in reducing pain and its intensity,frequency and duration of the attacks in females with migraine：a pilot study

OBJECTIVE:To evaluate the effects of feet reflexology versus segmental massage in reducing pain and its intensity, frequency and duration of the attacks in females suffering from migraine.METHODS:Forty eight females aged 33-58, suffering from migraine for 2 to 10 years were included in this study from November 2013 to November2015.The study protocol was carried out in Department of Chronic Diseases at the Regional Hospital in Zywiec.In the reflexology group(RG) the patients received a series of 10 treatments 2 times per week; in the segmental massage group(SMG) the patients received a series of 15 treatments 3 times per week.Pain during migraine attacks was assessed using the visual analog scale(VAS), and headache features such as intensity(IA), frequency(FA) and duration(DA) of attacks were assessed before the treatment, just after the treatment, 3months after the treatment.RESULTS:All variables(VAS, IA, FA and DA) decreased within RG and SMG 3 months after the treatment in compare with the baseline values, and the differences were statistically significant.The differences between groups were also statistically significant.CONCLUSION:Feet reflexology and segmental massage provide a safe alternative for the pharmacological treatment of migraine.The patients with migraine obtain significant health benefits with feet reflexology.

Clinical observation of tuina plus rehabilitation therapy for lower limb extensor spasticity in recovery stage of stroke

Objective: To observe the clinical efficacy of traditional tuina plus modern rehabilitation in the treatment of lower limb extensor spasticity during stroke recovery. Methods: A total of 93 stroke patients who met the inclusion criteria were randomly divided into an observation group and a control group. Forty-four patients in the observation group were treated with traditional tuina plus modern rehabilitation, and 49 patients in the control group were treated with modern rehabilitation. The modified Ashworth scale (MAS), the Fugl-Meyer assessment scale (FMA) and the modified Barthel index (MBI) were used to evaluate the knee extensors state, lower limb motor function and activities of daily living (ADL) of the two groups. Results: After treatment, the overall efficacy of the observation group was better than that of the control group, and the difference was statistically significant (P<0.05). After treatment, the MAS scores of both groups were significantly lower, FMA and MBI scores were significantly higher, and the differences were statistically significant in each group (P<0.01). After treatment, the MAS score of the observation group was lower than that of the control group, and the differenee between the groups was statistically significant (P<0.01). The MBI score of the observation group was higher than that of the control group, and the differenee between the two groups was statistically significant (P<0.05). There were significant differences in the post-treatment changes in MAS, FMA and MBI scores between the two groups (all P<0.05). Conclusion: Traditional tuina plus modern rehabilitation therapy can effectively alleviate or prevent lower limb extensor spasticity after stroke, and improve limb mobility and ADL. Hence, it is worthy of clinical promotion.