救援车载钻机同步自平衡式给进系统设计与应用

车载钻机是矿山事故地面钻孔救援的核心装备,在国内外历次成功救援中发挥了重要作用,给进系统是车载钻机的主要执行机构,使用过程中暴露出长工作行程制约整机通过性、定位轮系维护困难、双油缸运动同步性不强、动力头偏载引起导轨磨损、液压表显示起拔力延时等问题。研制的ZMK5550TZJF50/120型救援车载钻机采用基于油缸—钢丝绳倍速传动机构的伸缩桅杆式结构,实现了长工作行程和短运输尺寸;设计快换式轮系、钢丝绳防扭转张紧系统,解决一二级给进机身的辅助定位系统安全保护和维护困难的难题;采用给进系统油路同步补偿和先导控制技术,解决给进装置双油缸同步的难题;研发抽屉式调平体和测力销轴结构,实现动力头钻进过程中自平衡式调节及起拔力监测。经过静态、模态分析、应变测试和现场工业性应用,给进系统最大起拔力达1205 kN,能够有效处理大直径救援井施工过程中卡钻、埋钻等孔内事故,配合动力头、钻杆加卸系统,具有快速起下钻具功能,可大幅度提高倒杆效率,单根起下钻效率小于3 min/根。研究结果表明:救援车载钻机伸缩桅杆式给进装置运输尺寸短,钻机机动性强,道路通过性好;现场试验中处理了多次孔内卡钻、埋钻事故隐患,稳定和可靠性较高、可维护性好、起拔力监测准确、倒杆效率高,可以满足600 m深度救援井施工需求。给进装置轻量化,以及执行系统、传动系统、动力系统之间的响应匹配优化研究是今后的重点方向。

新型野战手术车存在问题及改进方法

本文通过对自主研制的新型野战手术车进行一系列实际操作训练,总结了其在千斤顶以及发电机的放置位置、车厢体的调平、车厢展开后的密封等诸多方面存在的一些问题,并针对问题提出了相关改进建议,以最大程度地发挥新型野战手术车的功效,为应急伤病员的救治提供最佳保障。

Chronic constipation:Facilitator factor for development of varicocele

AIM:To evaluate the possible relationship between varicocele and chronic constipation.METHODS:Between April 2009 and May 2010,a total of 135 patients with varicocele or constipation and 120 healthy controls were evaluated.Patients were divided into two groups.In both groups detailed medical history was taken and all patients were examined physically by the same urologist and gastroenterologist.All of them were evaluated by color Doppler ultrasonography.All patients with constipation,except for the healthy controls of the second group,underwent a colonoscopy to identify the etiology of the constipation.In the first group,we determined the rate of chronic constipation in patients with varicocele and in the second group,the rate of varicocele in patients with chronic constipation.In both groups,the rate of the disease was compared with age-matched healthy controls.In the second group,the results of colonoscopies in the patients with chronic constipations were also evaluated.RESULTS:In the first group,mean age of the study and control groups were 22.9 ± 4.47 and 21.8 ± 7.21 years,respectively(P < 0.05).In the second group,mean age of the study and control groups were 52.8 ± 33.3 and 51.7 ± 54.3 years,respectively(P < 0.05).In the first group,chronic constipation was observed in 8 of the 69 patients with varicocele(11.6%) and 3 out of 60 in healthy controls(5%),respectively.In this regard,there was no statistical significance between varicocele patients and the healthy control(P = 0.37).In the second group,varicocele was observed in 16 of the 66 patients with chronic constipation(24.24%) and 12 out of 60 in healthy controls(20%) respectively.Similarly,there was no statistical significance between chronic constipation and healthy controls(P = 0.72).Internal/external hemorrhoids were detected in 4 of the 16 patients with chronic constipation and varicocele,in the second group.In the remaining 50 patients with chronic constipation 9 had internal/external hemorrhoids.In this regard,there was no statistical significance between chronic constipation and healthy controls(P = 0.80).CONCLUSION:Chronic constipation may not be a major predictive factor for the development of varicocele,but it may be a facilitator factor for varicocele.

Antidepressant-like effect of active fraction of Polyrhachisvicina Roger in a rat depression model

OBJECTIVE: To investigate the antidepressant-likeeffect of active fraction of Polyrhachis vicina Roger(AFPR) in a rat depression model, and to elucidate the underlying mechanism.METHODS: AFPR was extracted with ethanol followed by petroleum ether. Its antidepressant-like effect was investigated in mice by tail suspension test(TST), forced swimming test(FST) and open field test(OPT). A repeated dose of reserpine(0.5 mg/kg, daily for 14 d) was used to establish a rat depression model. Fluoxetine was used as positive control agent. The effect of AFPR on reserpine-induced ptosis, hypothermia and akinesia, the levels of monoamines and their metabolites, and the activity of monoamine oxidase(MAO) in hippocampus and prefrontal cortex were determined.RESULTS: Administration of AFPR by gavage at 160 and 320 mg/kg significantly reduced the duration of immobility in the FST and TST, and did not affect locomotor activity in the OPT. In the reserpine-induced depression model, AFPR attenuated anhedonia, demonstrated by reversing hypothermia, akinesia and sucrose consumption. AFPR significantly increased the concentration of monoamines, including dopamine, serotonin, noradrenaline and acetylcholine.CONCLUSION: AFPR normalized the metabolism rates of noradrenaline, serotonin and dopamine,and the activity of MAO, which were altered by chronic reserpine exposure. The findings suggest that modulation of the monoaminergic neurotransmitter system likely underlies the antidepressant-like effect of AFPR.

Impaired function of the suprachiasmatic nucleus rescues the loss of body temperature homeostasis caused by time-restricted feeding

The suprachiasmatic nucleus(SCN)is the master circadian pacemaker that drives body temperature rhythm.Time-restricted feeding(TRF)has potential as a preventative or therapeutic approach against many diseases.The potential side effects of TRF remain unknown.Here we show that daily 4-h TRF treatment in mice can severely impair body temperature homeostasis and can result in lethality.Nearly half of the mice died at 21℃,and all mice died at 18℃during 4-h TRF.This effect was modulated by the circadian clock and was associated with severe hypothermia due to loss of body temperature homeostasis.Remarkably,disrupting the circadian clock by SCN lesions or constant light rescued lethality during TRF.Analysis of circadian gene expression in the dorsomedial hypothalamus(DMH)demonstrated that TRF reprograms rhythmic transcriptome in DMH and suppresses expression of genes,such as Ccr5 and Calcrl,which are involved in thermoregulation.Together,our results demonstrated a potent effect of TRF on body temperature homeostasis and the role of SCN function in this process.Our results further suggested that circadian arrhythmicity can have potential beneficial effects under certain stress conditions.

Thirty years of reform and opening up summarized from the perspective of Marxist philosophy

Overall reflection on the thirty years of reform and opening up from the perspective of Marxist philosophy will demonstrate that every policy involved in this undertaking has undergone a process of the negation of negation that includes the phases of affirmation, negation and integration. A new round of integration on a higher level can only be assured by a new round of the negation of negation targeting new contradictions. In making a dialectical evaluation of these three decades, we should not only fully acknowledge the great achievements of this period, but also recognize the problems and underlying risks, such as the contradictions between the productive forces and relations of production, the economic foundation and the superstructure, and ideology and social being, as well as those within the productive forces and the relations of production. With regard to the mechanism of economic operation, we need to place a renewed emphasis on the state＇s role in macroeconomic regulation at the same time as we carry out market-oriented reform. In respect of the ownership structure, we need a renewed emphasis on ＂public ownership as the mainstay＂ while different forms of ownership continue to develop together. And when it comes to distribution relations, ＂letting some people get rich first＂ should be changed to ＂attaching greater importance to social equity.＂