减速机螺旋圆锥齿轮啮合侧间隙及成对圆锥滚子轴承间隙调整

二轧厂改造后的主轧线设备大量运用了圆锥齿轮传动和成对圆锥滚子轴承，经过一年多的运行，我们对圆锥齿轮及成对圆锥滚子轴承的传动性能以及检修维护等方面有了一定的了解。以二轧厂5V、7V轧机的主传动减速机为例，为圆锥齿轮的啮合侧间隙以及成对圆锥滚子轴承间隙的调整方法进行阐述。     

7‘SHD短头型圆锥破碎机的选用

本文阐述了７’ＳＨＤ短头型圆锥破碎机的结构特点、液压技术的应用及几点注意问题与改进措施。     

7′SHD短头型圆锥破碎机的选用

本文阐述了7'SHD短头型圆锥破碎机的结构特点、液压技术的应用及几点注意问题与改进措施.     

圆锥破碎机腔型对性能的影响及改进

本文介绍分析了 7英尺symons中 ,细碎圆锥破碎机腔型及其磨损变化规律 ,提出了中细碎腔型的组合与设计改进 ,并进行了实验验证     

圆锥齿轮加工仿型机构的设计改进

圆锥齿轮加工仿型机构,适用于我国矿山冶炼设备的圆锥破碎机传动装置中圆锥齿轮齿形加工领域。应用本技术,根据伞齿刨床传动机构的仿型功能,利用走型板实现伞齿刨床上圆锥齿轮的齿形加工,解决圆锥齿轮齿形加工难题,既提高了圆锥齿轮加工精度又提高了圆锥齿轮加工的效率,为高性能、高质量的圆锥齿轮生产提供了技术保障。     

HP500圆锥破碎机无垫铁安装方法的应用

介绍了泗洲选矿厂HP500圆锥破碎机更新安装时,设备基础材料选用CGM灌浆料,圆锥破碎机底板采用无垫铁安装法安装。圆锥底板采用地脚螺栓与底板一体化安装法,简化了安装工序,提高了安装效率和安装精度,缩短了施工周期,圆锥基础受力更均匀,稳定性更好。     

7′超重型圆锥MC尼龙衬套试用情况分析

分析了 7′超重圆锥破碎机直衬套 ,由MC尼龙取代铜做成衬套 ,在试用过程中出现的现象 ,并对如何确定产品的尺寸进行了说明 ,认为改性MC尼龙衬套可以成为铜衬套的替代品     

圆锥破碎机在铀矿冶中的应用

总结了铀矿冶生产中常用的圆锥破碎机的特点和适用工况,介绍了圆锥破碎机在铀矿冶生产中的应用现状,提出了圆锥破碎机的配置要点和工艺设计思路。     

圆锥破碎机飞锥故障产生原因及处理办法

文章介绍了圆锥破碎机的工作原理和特点,详细描述了圆锥破碎机特有飞锥故障产生的原因并进行了力学分析;结合现场工作实际提出解决方案,可有效预防和治理圆锥破碎机出现的飞锥故障.     

泗洲选矿厂HP800圆锥破碎机应用实践

泗洲选矿厂碎一工段由于84″液压圆锥破碎机使用年限已久,用HP800圆锥破碎机替代其进行生产。着重介绍了HP800圆锥破碎机的特点及其在泗洲选矿厂的应用情况,生产应用表明HP800圆锥破碎机破碎效果明显,能有效改善碎矿最终产品粒度,实现"多碎少磨",并能降低电耗,节约生产成本。     

Nature of the curves of the cranial vault and their relationship with various brain structures

A radiometric investigation for various angles of two dry craniums and of the encephalographic or cerebral arteriographic pictures of 250 subjects has revealed the following facts: The architectural lines of the dome of the skull found by orthogonal projection of the profile, from the front, and in vertical projection, are hyperbolic spirals starting from the base of the skull and converging on the sphenoid. These lines join up in the parietal region forming a hyperbole. The frontal spiral is a simple hyperbolic spiral. The temporal spiral is of the lituus type. The axes of these lines converge in a frontal plane on the epiphysis. The axis of the parietal hyperbole on a projection of the profile passes through the epiphysis and is followed by the parietal artery. Central cranio-encephalic formations follow the same spiral path. The contour of the upper edge of the cerebellum is a lituus spiral. The outline of the lower part of the cerebellum is a simple hyperbolic spiral. The right side of the polar origins of a spiral plotted in the plane of the insula coincides with the right side of the opercula. It can always be plotted, in theory, and forms an angle of 22 degrees 30' with the right side of the median frontal spiral. It cuts the axis of the parietal hyperbole at the apex of the insular triange. The bissector of the angle formed by the two right sides of the polar origins bissects the axis of the parietal hyperbole at a point corresponding to the epiphysis. The temporal hyperbolic lituus spiral has its focal point under the anterior, clinoid, at the junction of the segments CII and CIII of the carotid siphon the curve of which follows the convolutions of the temporal spiral. The right side of the polar origins of this curve indicates the mean direction of the posterior cerebral. The contours of the corpus callosum are homothetic with those of the dome of the skull as far as the axis of the parietal hyperbole. The frontal and parietal curves converge according to four types in the main Pacchionian granulations. The sections of the frontal spiral are often marked by bone abnormalities on the internal table. This analytic test is invariably valid whatever the constants of the spirals or the eccentricities of the hyperboles. Combinations between spirals with different constants and hyperboles of various eccentricities amount to very many types which call for separate study.     

Influence of pre-reduction of ore on the temperature profile inside a submerged-arc furnace producing ferro-chromium

The temperature profile inside the submerged-arc furnace (S.A.F) has a significant influence on the quality of the ferro-chromium produced. This profile is controlled by the degree of pre-reduction the ore is subjected to. A mathematical model has been developed to describe the temperature profile inside the S.A.F and the influence of pre-reduction on the profile has been explored. Increasing levels of pre-reduction increases the temperatures in the various zones of the furnace. Other factors remaining the same, this is expected to increase the level of silicon in the hot metal. This can be controlled by controlling the heat generated in the furnace.     

MRI visualization of multiple sclerosis lesions

Magnetic resonance imaging represents voxels (volume elements) of the body placed in a magnet, by their magnetization determined under various acquisition conditions weighting the contrast of the image by the density of free water protons and their relaxation times T1 and T2. Thus, the sensitivity in depicting lesions is high but pathological specificity is poor. Efforts are made to increase the diagnosis powerfulness of M.R.I. in multiple sclerosis: a careful correlation with the clinical presentation and the use of better M.R.I. criteria increase the specificity of the conventional T2 sequences. New sequences such as fast spin echo (F.S.E.), turbo spin echo (T.S.E.) or derived from inversion recovery (F.L.A.I.R.: fluid attenuated inversion recovery) improve the detection of lesions. Under specific conditions M.R.I. can be used to monitor the evolution of M.S. Acute phase monitoring focuses on changes in disease activity, new, recurring, enlarging, gadolinium (Gd) enhancing lesions, and chronic phase monitoring appreciate the burden of the disease. However M.R.I. is always considered as a secondary outcome in the phase III trials because insufficient correlations with the clinical disability. In the neurological daily practice conventional M.R.I. is of poor interest in the follow up of individual M.S. patients considering the weakness of prognosis value and the problems in the measurement of the lesions load which is emphasized in the methodology of the clinical trials. Nevertheless, there is a continuing search for techniques which correlate better with clinical measures of the disease such as the quantification of "black holes" on T1 w images or the cerebral and spinal atrophy. New techniques allow to weight the signal by the movement (diffusion imaging), by the complexity of the molecular architecture (magnetization transfer imaging), by the chemical shift (chemical shift imaging) or by the local status of oxygenation (functional M.R.I.). The basic aspects of the pathological lesions in M.S., edema, membrane disruption, demyelination, gliosis, cellular infiltration and axonal loss can be studied more precisely by these new M.R. techniques which should better describe the actual clinical impact of the destructive process. In the last year the importance of axonal loss has simultaneously been confirmed by M. R. spectroscopy and pathological findings. However, magnetization transfer imaging, M.R. diffusion imaging and functional M.R.I. are intensively under investigation for a better analysis of these different factors conditioning the reversibility of the patient disability.     

变工况过程中球轴承保持架的稳定性

建立了球轴承ADAMS多体动力学模型，考虑轴承各元件之间的相互碰撞作用及摩擦力，分析了变工况下动量轮用球轴承的保持架质心的涡动行为，对保持架的运行稳定性做出了定量的分析。讨论了轴承启动加速度大小、轴向载荷和有无重力场对保持架稳定性的影响。结果表明轴承启动加速度增加，缩短了轴承启动过程的时间，引导面对保持架的引导作用增强，较高的转速更有利于保持架运行的稳定，但较大的启动加速度使得轴承摩擦力矩较大；轴向载荷升高加剧了滚动体与保持架的碰撞，增加了保持架的涡动状态，而且轴向载荷的增加使得轴承摩擦力矩增加；失重状态下保持架与套圈的碰撞加剧，保持架涡动增加。      

A model for self-sustained potential oscillation of lipid bilayer membranes induced by the gel-liquid crystal phase transitions

To clarify the mechanism of self-sustained oscillation of the electric potential between the two solutions divided by a lipid bilayer membrane, a microscopic model of the membrane system is presented. It is assumed, on the basis of the observed results (Yoshikawa, K., T. Omachi, T. Ishii, Y. Kuroda, and K. liyama. 1985. Biochem. Biophys. Res. Commun. 133:740-744; Ishii, T., Y. Kuroda, T. Omochi, and K. Yoshikawa. 1986. Langmuir. 2:319-321; Toko, K., N. Nagashima, S. liyama, K. Yamafuji, and T. Kunitake. Chem. Lett. 1986:1375-1378), that the gel-liquid crystal phase transition of the membrane drives the potential oscillation. It is studied, by using the model, how and under what condition the repetitive phase transition may occur and induce the potential oscillation. The transitions are driven by the repetitive adsorption and desorption of proton by the membrane surface, actions that are induced the periodic reversal of the direction of protonic current. The essential conditions for the periodic reversal are (a) at least one kind of cations such as Na+ or K+ are included in the system except for proton, and the variation of their permeability across the membrane due to the phase transition is noticeably larger than that of proton permeability; and (b) the phase transition has a hysteresis. When these conditions are fulfilled, the self-sustained potential oscillation may be brought about by adjusting temperature, pH, and the cation concentration in the solutions on both sides of the membrane. Application of electric current across the membrane also induces or modifies the potential oscillation. Periodic, quasiperiodic, and chaotic oscillations appear especially, depending on the value of frequency of the applied alternating current.     

The mechanism of the excitatory action of catecholamines and histamine on the smooth muscle of guinea-pig ureter

1. The ionic mechanism of the excitatory action of catecholamines and histamine on the smooth muscle cells of guinea-pig ureter was studied with the double sucrose-gap method. 2. In normal conditions adrenaline and noradrenaline in a concentration of 10(-5) g/ml., and histamine in a concentration of 10(-6) g/ml., prolonged the duration of the plateau of the action potential and increased the amplitude and duration of the phasic contraction. Sometimes these changes were accompanied by a slight depolarization of the muscle membrane and by a small increase (with noradrenaline) or decrease (with histamine) of the membrane resistance. The amplitude and duration of the fast spike component of the action potential were not changed. 3. Isoprenaline in a concentration of 10(-5) g/ml. either caused no change or it decreased the duration of the plateau, reduced the amplitude of contractions and reduced excitability. 4. Tetraethyl ammonium (TEA; 5 mM), which blocks the delayed outward K current, did not prevent the increase in the duration of the plateau nor the increase of the amplitude and duration of the contractions by noradrenaline and histamine. 5. In Na-free or in K-free solution or in the presence of ouabain, i.e. in conditions in which the Na-gradient across the membrane was reduced, noradrenaline and histamine were unable to increase the duration of the plateau and the amplitude and duration of the contraction. 6. In the presence of Mn2+ (2 mM) which suppressed the spike component of tha action potential and the phasic contraction, theeffects of noradrenaline and histamine were almost abolished. 7. The results suggest a dual ionic mechanism of the alpha-action of catecholamines and of the action of histamine on the smooth muscle of ureter: (1) these drugs affect the passive ionic permeability of the membrane in a manner that results in depolarization; (2) they specifically activate the potential-dependent conductance of the slow Na channels, thereby increasing the plateau duration. The increased amplitude and duration of the contraction is the result of their primary effect on the plateau of the action potential.     

Comparative analysis of diagnoses by the referring family physician and the hospital admission committee in ambulatory patients at an internal medicine department

The objectives of the present study were, as follows: 1. To what rate do the primary care doctors refer their patients to the regional internal medicine emergency department? 2. What sort of problems are the reasons of the referring? 3. To what extent are the opinions of the referring doctors confirmed or reviewed by the specialists? 4. What rate of the referred patients are admitted or discharged after the urgent consultations and-or interventions. 5. What kind of additional tests were used by the institutional caregivers in order to make accurate diagnoses? 6. What was the fate of the unaccepted patients? Data were collected in the patient document archive of the First Dept. of Medicine of the Albert Szent-Gy?rgyi Medical University, Szeged, Hungary. Each patients' referring notes and inpatient charts between September 15th, 1995 and January 15th, 1996 were studied in a retrospective way. Upon the results of the study, it was concluded, as follows: The primary care doctors referred their patients with right orientation diagnosis to the emergency department in 70% of the cases. 45.8% of the referred pts. were admitted to the internal inpatient ward. The agreement of the referring and discharge diagnoses was greater (85.7%) among the admitted patients as compared to the unaccepted ones (56.8%). 14% of the referred pts. were referred to other specialists by the internists. On the basis of the results the actual messages of the study for an under- and postgraduate medical teaching group, and for the health care politicians are discussed in the paper.     

Dermomyotomal origin of the ribs as revealed by extirpation and transplantation experiments in chick and quail embryos

To elucidate role of the dermomyotome in the formation of the axial skeleton, we performed extirpation and transplantation experiments on the dermomyotomes in chick and quail embryos. When the thoracic dermomyotomes of chick embryos were removed, the intercostal muscles and the distal ribs were deficient, while the proximal ribs were more or less normal. Quail tissues including the dermomyotome, the ectoderm and the medial edge of lateral plate, were transplanted to replace chick dermomyotomes. In these chimeras, the ribs, which would be deficient without the back-transplantation, were recovered. The cells of the recovered part of the ribs as well as the intercostal muscles were derived from the quail transplants. These findings suggest that the distal rib originated from the dermomyotomes and not the sclerotome as previously believed. To localize the origin of the distal rib further, we removed restricted regions of the dermomyotomes along the mediolateral and the rostrocaudal axis. The more lateral the part of the dermomyotomes that we removed, the more distal the part of the ribs affected. On the contrary, when the rostral and caudal edges of the dermomyotomes were removed, only the vertebral ribs showed extensive deficiencies while removal of the middle part between the edges caused less deficiency. The sternal ribs were not deficient in either case, but were extensively affected when the entire lateral edge of dermomyotomes was included in the region removed. We conclude that the lateral edges of the dermomyotomes are the primordia of the sternal ribs, and the rostral and/or caudal edges of the medial part of dermomyotomes are the primordia of the distal part and not of the proximal part of the vertebral ribs.     

Regulating energy transfer in the ATP sulfurylase-GTPase system

ATP sulfurylase, isolated from Escherichia coli K-12, is a GTPase-target complex that catalyzes and links the energetics of GTP hydrolysis to the synthesis of activated sulfate (APS). When the GTP concentration is saturating and held fixed with a regenerating system, the APS reaction reaches a steady state in which its mass ratio is shifted (5.4 x 10(6))-fold toward the product by the hydrolysis of GTP. If GTP is not regenerated, the shift toward the product is transient, producing a pulse-shaped progress curve. The mechanistic basis of this transience is the subject of this paper. The product transient is caused by the binding of GDP to the enzyme which establishes a catalytic pathway that allows the chemical potential that had been transferred to the APS reaction to "leak" into the chemical milieu. The system leaks because the E.GDP complex catalyzes the uncoupled APS reaction. The addition of phosphate to the leaky GDP.E.APS.PPi complex converts it into the central Pi.GDP.E.APS.PPi complex which catalyzes the energy-transfer reaction. Thus, Pi binding directs the system through the coupled mechanism, "plugging" the leak. GMPPNP, which also causes a leak, is used to demonstrate that the mass ratio of the APS reaction can be "tuned" by adjusting flux through the coupled and uncoupled pathways. This energy-coupling mechanism provides a means for controlling the quantity of chemical potential transferred to the APS reaction. This versatile linkage might well be used to the cell's advantage to avoid the toxicity associated with an excess of activated sulfate.     

带结晶器电磁搅拌的大圆坯连铸的数值模拟

在圆坯连铸中,结晶器电磁搅拌器(M-EMS)是常见的改善钢流内流场的手段。众所周知,液芯的流动对最终产品的质量有着重要影响,用M-EMS能优化凝固前沿的流速,进一步促进柱状晶向等轴晶的转变,进而改善铸坯的表面和皮下缺陷。在奥钢联多纳维茨钢厂,绝大多数产品的生产都应用了M-EMS。由于在奥钢联多纳维茨钢厂的恶劣环境下难于进行测量,因此研究采用数值模拟的方法。连铸过程1:1比例的物理模拟也很难实现,因为水的传导率太低,且液态金属不透明或金属处理难,因此数值模拟就成为获得整个过程较好的重要手段。数值模型考虑了流场和电磁场的完全耦合,许多物理问题都用最优参数进行模拟,流场用商业有限元CFD编码软件FLUENT进行计算,电磁场用商业有限元求解器ANSYSEMAG计算。采用这种方法可以研究各种参数对流场和凝固组织的影响,也能揭示搅拌频率和搅拌强度的变化对液芯内部流场的影响。应用数值模拟能够加深对电磁场下连铸过程的认识,也能够找到优化的参数。