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关键词： 离合器磨损   小型拖拉机   调整   保养   主要部件   传动系统   操作要领   输出转矩  

摘要： 离合器是小型拖拉机传动系统中的主要部件之一。驾驶员在拖拉机工作中使用离合器时，必须掌握离合器的正确操作要领，保证离合器在工作时能有效可靠地传递发动机的输出转矩，减少离合器磨损。应按要求对离合器进行正确保养和调整，以保证离合器工作正常。

关键词： 摩擦片式离合器   离合器分离   离合器故障   诊断   拖拉机驾驶员   离合器打滑   离合器异响   离合器发抖  

摘要： 离合器是拖拉机传动系统中的重要部件之一，离合器工作质量好坏关系到拖拉机的行驶性能、动力性能、操作性能和可靠性能。离合器出现故障就会使拖拉机工作不正常，影响拖拉机效率的发挥。目前拖拉机上广泛应用摩擦片式离合器。离合器在工作中常见的故障有离合器打滑、离合器分离不彻底、离合器发抖及离合器异响等。在诊断离合器故障时，要对故障现象进行多方面的、有针对性的综合分析，才能对故障做出准确地判断，最后排除故障。以下对离合器分离不彻底故障的诊断与排除进行叙述，供拖拉机驾驶员及维修人员参考。

关键词： Magnetorheological fluid   magnetorheological clutch   mechanical design   magnetic design   permanent magnet   modeling and experimentation   automotive   HIGH-TORQUE   DESIGN   FLUID  

摘要： This work was carried out in the framework of a funded project aimed at evaluating the feasibility of an ad hoc clutch for the disengagement an auxiliary device, i.e. the vacuum pump used with the powerbrake in diesel engine vehicles, when its operation is not required. In this way it is possible to improve the overall vehicle efficiency. Strict design specifications were defined with reference to available room, torque transmission, absence of axial loads and fail-safe operation. A magnetorheological clutch with permanent magnets was conceived to fulfil the technical requirements. Different clutch geometries were compared with particular reference to the fail-safe operation and torque capabilities. After an iterative procedure, in which both mechanical design and magnetic field analyses were considered, the most promising solution was defined and a prototype was built and tested. A four-pole sliding permanent magnet was adopted to generate the magnetic field. The experimental results validated the developed models and demonstrated the feasibility developed models and demonstrate the feasibility of the proposed solution. A principle for the automatic clutch actuation is also presented.

关键词： Automobile repair shops   Temperature sensors   Automatic automobile transmissions   Clutches (Machinery)   Gearing  

摘要： The article discusses the use of the Transmission Fluid Temperature (TFT) Sensor in diagnosing and repairing automatic transmission. Topics covered include the transformation of the TFT Senor from being a mere switch which was later used for converter clutch control, its various uses for manufacturers such as for computing 'in gear' engine run time, and the different problems it can make, namely delayed clutch engagements, late shifts, and loss of high gear.

关键词： Agonistic   Fernando de Noronha   Reproduction   Rocas Gregory   Southwestern Atlantic   FISH COMMUNITY STRUCTURE   DE-NORONHA ARCHIPELAGO   CORAL-REEF   BEAUGREGORY DAMSELFISH   TERRITORIAL DAMSELFISH   REPRODUCTIVE SUCCESS   DUSKY DAMSELFISH   WESTERN ATLANTIC   RESOURCE USE   INTERSPECIFIC TERRITORIALITY  

摘要： This study aimed at comparing the feeding, territorial and agonistic behavior of the Rocas Gregory Stegastes rocasensis when guarding egg clutches. This was accomplished through underwater observations of 80 S. rocasensis individuals observed in four sampling sites in the Fernando de Noronha archipelago (SW Atlantic). Several differences were detected in the behavior of S. rocasensis, such as the reduced size of the territory, the feeding preferences and the aggressiveness towards intruders. Males guarding eggs defended territories twice as small as the ones that did not present egg clutches inside their territories. Additionally, they fed mostly on turf algae, while individuals without eggs in their territories fed mostly on turf and macroalgae. Fish guarding egg clutches elicited agonistic reactions mainly towards planktivores and omnivorous fishes, which could potentially prey on their eggs, while individuals without eggs clutches in their territories elicited agonistic reactions mainly towards herbivorous fishes. The results of the present study reinforces that damselfishes are able to identify the intruder's identity and elicit agonistic reactions only toward species that may represent a threat to their eggs and/or farmed algae.

关键词： Tetrodotoxin   Salamandridae   Egg toxicity   TTX   LARVAL   STRAIN   TOXIN  

摘要： Tetrodotoxin is an enigmatic neurotoxin that is found in a wide-variety of organisms. Unfortunately, tetrodotoxin (TTX) toxicity across life-history stages is poorly understood in most organisms. Rough-skinned newts (Taricha granulosa) possess the greatest known quantities of TTX of any organism and numerous studies have begun to elucidate these patterns in this species. We conducted a series of studies to answer the following questions: (1) do eggs from a single female's clutch vary in toxicity? (2) does TTX concentration change during embryonic development? and (3) does the jelly coat from newt eggs possess TTX? We found that the amount of TTX in newt eggs depended on the relative "position" of the egg within a clutch; eggs deposited at the beginning of the clutch had substantially more TTX than those at the end. During development egg toxicity remained consistent until hatching. The jelly coat contained small quantities of TTX, but these were not correlated with the toxicity of the embryo. These results clarify several long-held interpretations about embryo toxicity and continue to elucidate the life-history patterns of tetrodotoxin toxicity in this amphibian. (C) 2014 Elsevier Ltd. All rights reserved.

关键词： Electro-hydrostatic actuator   Swash plate-type piston pumps   Power losses of piston shoe bearing   SLIPPER  

摘要： Swash plate type piston pumps, when applied to electro-hydrostatic actuators, operate mostly in the mixed lubrication speed range, compensating for position control errors of actuator parts. Therefore, their hydrostatic piston shoe bearings should be designed to minimize frictional and leakage losses as well as the wear rate, which could be increased by insufficient hydrodynamic lubrication in the low speed range. In this study the influence of the balance and recess ratios of piston shoe bearings on their power losses were investigated under mixed friction conditions. The fundamental properties of piston shoe bearings tilted on a swash plate, such as the lift force, righting moment and leakage flow rate, were computed using a simplified Navier-Stoke's equation, to obtain an insight into methods of minimizing the power losses of piston shoes exposed to mixed friction. Six test models were designed with these two parameters decoupled and tested on apparatus which was developed to measure the friction force and leakage flow rate of a piston shoe in the motor speed range below 100 rpm. The tilting motion of the piston shoes could be observed in the mixed friction speed range and power losses could be reduced by increasing their resistance to external tilting moments.

关键词： carcinoid tumour   Clutch Cutter   endoscopic submucosal dissection   endoscopic surgery   subepithelial lesion   GASTROINTESTINAL-TRACT   MUCOSAL RESECTION   SCISSORS FORCEPS   ASPIRATION METHOD   SNARE RESECTION   LIGATION DEVICE   LESIONS  

摘要： BackgroundTo reduce the risk of complications related to endoscopic submucosal dissection (ESD) using knives, we developed the Clutch Cutter (CC), which can grasp and incise the target tissue similarly to biopsy techniques using an electrosurgical current. The aim of this study was to evaluate the efficacy and safety of ESD using the CC for removal of rectal carcinoid tumours. MethodsBetween December 2009 and December 2011, we prospectively enrolled seven patients (seven lesions) on 7 different days. Patients were endoscopically diagnosed with rectal subepithelial lesions (upper rectum, n = 3; lower rectum, n = 4) within the level 3 layer and without lymph node involvement, with the diagnosis confirmed by preliminary endoscopy, endoscopic ultrasound and endoscopic biopsies. ESD using the CC was performed in all cases, and the therapeutic efficacy, safety and tumour recurrence were assessed. ResultsAll lesions were treated easily and safely, and there were no inadvertent incisions. En bloc resection was obtained in all cases, and histologic tumour-free lateral/basal margins were obtained in six of the seven patients. No delayed haemorrhage, perforation or tumour recurrence occurred. ConclusionESD using the CC appears to be an easy, safe and technically efficient method for resecting rectal carcinoid tumour.

关键词： Focal ischemia   Acute stroke   Neuroprotection   Rehabilitation   Reperfusion   FOCAL CEREBRAL-ISCHEMIA   FUNCTIONAL RECOVERY   SYNAPTIC PLASTICITY   EMBOLIC STROKE   RAT MODEL   KINASE   NEUROPROTECTION   SILDENAFIL   INJURY   PROTEIN  

摘要： Yonkenafil is a novel phosphodiesterase type 5 (PDE5) inhibitor. Here we evaluated the effect of yonkenafil on ischemic injury and its possible mechanism of action. Male Sprague-Dawley rats underwent middle cerebral artery occlusion, followed by intraperitoneal or intravenous treatment with yonkenafil starting 2 h later. Behavioral tests were carried out on day 1 or day 7 after reperfusion. Nissl staining, Fluoro-Jade B staining and electron microscopy studies were carried out 24 h post-stroke, together with an analysis of infarct volume and severity of edema. Levels of cGMP-dependent Nogo-66 receptor (Nogo-R) pathway components, hsp70, apaf-1. caspase-3, caspase-9, synaptophysin, PSD-95/neuronal nitric oxide synthases (nNOS), brain-derived neurotrophic factor (BDNF)/tropomyosin-related kinase B (TrkB) and nerve growth factor (NGF)/tropomyosin-related kinase A (TrkA) were also measured after 24 h. Yonkenafil markedly inhibited infarction and edema, even when administration was delayed until 4 h after stroke onset. This protection was associated with an improvement in neurological function and was sustained for 7 d. Yonkenafil enlarged the range of penumbra, reduced ischemic cell apoptosis and the loss of neurons, and modulated the expression of proteins in the Nogo-R pathway. Moreover, yonkenafil protected the structure of synapses and increased the expression of synaptophysin. BDNF/TrkB and NGF/frkA. In conclusion, yonkenafil protects neuronal networks from injury after stroke. (C) 2014 Elsevier Inc. All rights reserved.

关键词： ToF-SIMS   depth profiling   3D imaging   tribology   lubricant   wet clutch   friction   additives   ZDDP   phosphate glass   ZDDP   PERFORMANCE   TRIBOFILM   SURFACES  

摘要： The structure and chemical composition of boundary layers built under tribological stress impact the friction and wear of solid-state surfaces in a major way. Time-of-flight secondary ion mass spectrometry is ideally suited for the analysis of these boundary layers, including the adsorptive layer formed from oil additive components, and to advance the understanding of the interaction of all materials involved. Tribologically formed phosphate glass layers on friction body surfaces of standard wet multi-disc clutches, which had been exposed to defined loads in an environment of different model fluids of polyalphaolefin base oil blended with different single additives or well-defined mixtures of two additives, were investigated using time-of-flight secondary ion mass spectrometry. The obtained data give an insight on how additive-based reaction layers on friction surfaces may affect the friction curve of a wet clutch. Copyright (c) 2014 John Wiley & Sons, Ltd.