工程机械液力变速器(第十讲)变速器换挡品质电子控制(2)

7 单电液比例调压阀系统 早期川崎轮式装载机97ZⅢ自动变速器采用单电液比例调压阀系统,其电液比例调压阀由溢流阀、调压阀1、调压阀2和3个压力阀等组成,其结构原理如图8(a)所示,符号如图8(b)所示.     

Evolution of Quasicrystals and Long-Period Stacking Ordered Structures During Severe Plastic Deformation and Mixing of Dissimilar Mg Alloys Upon Friction Stir Welding

Microstructural evolution during severe plastic deformation and mixing of Mg_(95.8)Zn_(3.6)Gd_(0.6) and Mg_(97)Cu_1Y_2(at%) alloys upon friction stir welding was studied.A laminated onion-ring structure composed of alternative distribution of layers with significantly refined microstructures from diff erent alloys was formed in the stirred zone.Coarse quasicrystals were broken up and dispersed with most of them being transformed into cubic W-phase particles,and thick 18 R long-period stacking ordered plates were fractured and transformed into fine 14 H-LPSO lamellae in the stirred zone(SZ) experiencing complex material flow under high strain rate.Fine W-phase particles and 14 H-LPSO lamellae formed during dissimilar friction stir welding(FSW) usually have no specific orientation relationship with surrounding Mg matrix.Chemical measurements demonstrated occurrence of interdiff usion between dissimilar layers in the SZ.Phase transformation was observed for some particles of quasicrystals and long-period stacking ordered(LPSO) in regions slightly outside the SZ.An ultimate tensile strength of ～ 415 MPa and an elongation to failure of ～ 27.8%,both exceeding those of base materials,were obtained in the SZ,due to microstructural refinement and formation of a laminated structure.     

Degradation of polyimide induced by nitrogen laser irradiation

The degradation behavior of polyimide (PMDA-ODA) induced by nitrogen laser irradiation was studied. The changes in the surface morphology and the composition of the irradiated polyimide films were examined by scanning electron microscopy, X-ray photoelectron spectroscopy and FT-IR spectroscopy. The initial reaction was achieved by photochemical degradation of polyimide in the highly electronic excited state by the absorption of a second 337 nm photon. Atmospheric oxygen sequentially reacted with the produced radicals to form a highly oxidized layer. The formation of carbonyl group was enhanced by the heat remaining on the irradiated polyimide film surfaces.     

基于金属粉末激光烧结技术的研究进展

随着快速成形(RP)技术的进步,使用直接金属激光烧结(DMLS)技术加工金属粉末得到广泛关注。针对DMLS技术快速制造的特点,研究讨论了表面张力、粉末颗粒大小及分布、辅助材料的添加等粉末特征以及激光功率、扫描速度、扫描间距、铺粉厚度、扫描策略等工艺参数对烧结质量的影响,并对DMLS技术的发展方向作了简要分析。     

行星变速器杠杆分析法

行星机构比较复杂,传统的分析方法为数学解析法,但比较抽象,人难以直观理解。本文提出一种新的分析方法:杠杆法,即把行星机构转换成杠杆系来进行分析。并以ZF公司8速自动变速器来说明如何应用杠杆法来进行行星变速器传动方案分析。     

EFFECT OF PARTICULATE SIZE AND CONTENT ON STRENGTH OF SiC_p／2024Al COMPOSITE AND ITS RELATIONSHIP WITH T6－TREATMENT

ＥＦＦＥＣＴＯＦＰＡＲＴＩＣＵＬＡＴＥＳＩＺＥＡＮＤＣＯＮＴＥＮＴＯＮＳＴＲＥＮＧＴＨＯＦＳｉＣ_ｐ／２０２４ＡｌＣＯＭＰＯＳＩＴＥＡＮＤＩＴＳＲＥＬＡＴＩＯＮＳＨＩＰＷＩＴＨＴ６－ＴＲＥＡＴＭＥＮＴ￥Ｍａ，Ｚｏｎｇｙｉ；Ｌｉａｎｇ，Ｙａｎａｎ；Ｌｕ?..     

A Low‐Toxic Multifunctional Nanoplatform Based on Cu9S5@mSiO2 Core‐Shell Nanocomposites: Combining Photothermal‐ and Chemotherapies with Infrared Thermal Imaging for Cancer Treatment

Copper chalcogenides have been demonstrated to be a promising photothermal agent due to their high photothermal conversion efficiency, synthetic simplicity, and low cost. However, the hydrophobic and less biocompatible characteristics associated with their synthetic processes hamper widely biological applications. An alternative strategy for improving hydrophilicity and biocompatibility is to coat the copper chalcogenide nanomaterials with silica shell. Herein, the rational preparation design results in successful coating mesoporous silica (mSiO₂) on as‐synthesized Cu₉S₅ nanocrystals, forming Cu₉S₅@mSiO₂‐PEG core‐shell nanostructures. As‐prepared Cu₉S₅@mSiO₂‐PEG core‐shell nanostructures show low cytotoxicity and excellent blood compatibility, and are effectively employed for photothermal ablation of cancer cells and infrared thermal imaging. Moreover, anticancer drug of doxorubicin (DOX)‐loaded Cu₉S₅@mSiO₂‐PEG core‐shell nanostructures show pH sensitive release profile and are therefore beneficial to delivery of DOX into cancer cells for chemotherapy. Importantly, the combination of photothermal‐ and chemotherapies demonstrates better effects of therapy on cancer treatment than individual therapy approaches in vitro and in vivo.     

喷淋室挡水板过水量的节能分折

本文利用空调喷淋室送风时挡水板带一定的过水量,同时适当降低机器露点来增加送风焓差,降低送风量.根据纺织厂不同车间设计状态,分析过水量和风量节约的定量关系.以织造车间(相对湿度75%)为例,风量可节约35～45%,从而既降低了空调室设备和土建投资,又大大降低风机的运转能耗.其次本文还提出过水量还可以节的夏季设计冷量,并用计算机计算了江南某地连续三年的整个夏季送风带过水量和不带过水量时的总用冷量比.最后本文分折了冬季送风带过水量对空调过程和加热量的影响.总之,纺织厂的各类车间,在风道不滴水的前提下,应利用较大的过水量,以利节能.     

一种基于概率密度的多基阵声测被动定位算法

研究了基于概率密度分析的多基阵声测被动定位方法，并对定位算法和误差进行了理论分析和数值仿真。该方法将单基阵估计的目标方位看成是满足一定概率分布的一种可能的目标位置测量子集，根据每个单基阵得到的目标位置概率，计算目标位置在整个空间的概率密度分布，将概率密度最大点作为目标位置。研究结果表明，该声测被动定位方法的定位精度明显优于几何交叉定位法，具有重要的实用价值，它不仅可直接用于空中运动目标的探测和定位，而且也适用于地面运动目标的探测与定位。