45号钢垫圈断裂的原因分析和改进措施

针对45号钢垫圈在装配后发生断裂的情况,对45号钢垫圈进行断口形貌分析、力学性能分析、化学成分分析和金相组织分析。宏观形貌显示内孔存在加工台阶和明显刀痕,能谱测试发现断裂起始处存在锌元素,金相组织分析确认内孔加工面存在微裂纹。结合加工工艺分析,确认45号钢垫圈的断裂原因,并提出改进措施。     

Unveiling the role of Fe3O4in polymer spin valve near Verwey transition

The spinterface formed between ferromagnetic(FM)electrode and organic materials is vital for performance optimization in organic spin valve(OSV).Half-metallic Fe₃O₄with drastic change in structure,conductivity and magnetic property near Verwey transition can serve as an intrinsic spinterface regulator.However,such modulating effect of Fe₃O₄in OSV has not been comprehensively investigated,especially below the Verwey transition temperature(Tv).Here,we highlight the important role of Fe₃O₄electrode in reliable-working and controllable Fe₃O₄/P3HT/Co polymer spin valves by investigating the magnetoresistance(MR)above and below 7V.In order to distinguish between different contributions to charge transport and related MR responses,the systematic electronic and magnetic characterizations were carried out in full temperature range.Particularly,the first-order metal-insulator transition in Fe₃O₄has a dramatic effect on the MR enhancement of polymer spin valves at 7V.Moreover,both the conducting mode transformation and MR line shape modulation could be accomplished across 7V.This research renders unique scenario to multimodal storage by external thermodynamic parameters,and further reveals the importance of spin-dependent interfacial modification in polymer spin valves.     

A dynamic SVR–ARMA model with improved fruit fly algorithm for the nonlinear fiber stretching process

Natural Computing - The fiber stretching process plays the key role in the process of fiber production and its effects is measured by the stretching ratio. The stretching ratio is determined by the...     

轧制始极片

本文介绍了轧制法生产始极片的工艺，比较了轧制法和传统的钛种板生产始极片的优缺点，讨论了采用轧制始极片的经济效益和应用前景。     

浅谈焦炉煤气鼓风机高压变频调速控制系统的设计

本文对焦炉煤气加压控制系统进行了分析，在焦炉煤气加压机控制系统中运用变频调速技术对其进行改造，从而实现煤气加压机运转的自动调节，有效地稳定了焦炉煤气母管压力，保证了安全运行，并且达到节约能源的效果。解决了两台鼓风机并列运行，靠调节回流阀无法实现压力恒定这个始终困扰焦炉生产的难题。     

An inventory analysis of rural pollution loads in China.

Rural pollution has attracted increasing attention over the past decade for its important consequences on surface and groundwater quality. This is particularly so in China due to the wide and effective control of industrial and municipal wastewater discharges over the past decade. Based on the discussion of rural activities in China, this paper develops a new method of inventory analysis through the definition of elementary unit (EU). This inventory analysis approach is then applied to estimate the total rural pollution loads of COD, TN and TP, as well as their spatial distributions in China. Further analysis is also conducted to investigate the correlations between rural pollution loads and agricultural production outputs, as well as population. It is found that China's agriculture is developing largely at the cost of environment quality, and a high population, as well as the increasing demand for agricultural products, is one of the dominant driving forces. The constructed EKC, which describes the relationship between rural pollution loads and agricultural income, also reveals that current agricultural development in China is mostly far from de-locked from the environmental problem.     

Performance study of iSCSI-based storage subsystems

iISCSI is emerging as an end-to-end protocol for transporting storage I/O block data over IP networks. By exploiting the ubiquitous Internet infrastructure, iSCSI greatly facilitates remote storage, remote backup, and data mirroring. This article evaluates the performance of two typical iSCSI storage subsystems by measuring and analyzing block-level I/O access performance and file-level access performance. In the file-level performance study, we compare file access performance in an NAS scheme with that in an iSCSI-based SAN scheme. Our test results show that Gigabit Ethernet-based iSCSI can reach very high bandwidth, close to that of a direct FC disk access in block I/O access. However, when the iSCSI traverses through longer distance, throughput relies heavily on the available bandwidth between the initiator and the target. On the other hand, the file-level performance shows that iSCSI-based file access (SAN scheme) provides higher performance than using NFS protocol in Linux and SMB protocol in Windows (NAS scheme). However, the advantage of using iSCSI-based file accesses decreases as the file size increases. The obtained experimental results shed some light on the performance of applications based on iSCSI storage.     

Experimental and modeling approaches of MR behaviors under large step strains

Rheological properties of MR fluids under large step strain shear are presented in this paper. The experiments were carried out using a rheometer with parallel-plate geometry. Under the large step strain shear, MR fluids behave as nonlinear viscoelastic properties, where the stress relaxation modulus, G(t, γ), shows a decreasing trend with step strain. The experimental results indicate that G(t, γ) obeys time-strain separability. Thus, a mathematical form based on finite exponential serials is proposed to predict MR behavior. In this model, G(t, γ) is represented as the product of a linear stress relaxation, G(t), and the damping function, h(γ), i.e. G(t, γ)=G(t) h(γ). G(t) is simply represented as a three-parameter exponential serial and h(γ) has a sigmoidal form with two parameters. The parameters are identified by adopting an efficient optimization method proposed by Stango et al. The comparison between the experimental results and the model-predicted values indicates that this mathematical model can accurately predict MR behavior.     

柯克亚油气田混合来源天然气的地球化学特征

柯克亚油气田是我国开发比较早的一个油气田,但由于受混源和其他因素的影响,对气源的认识众说纷纭。通过对天然气的地球化学特征的分析,并参照国内外关于甲烷、乙烷、丙烷碳同位素关系方面的资料,提出了如下看法:柯克亚天然气碳同位素相对较重,与塔里木盆地下古生界海相天然气的碳同位素组成区别较大;根据天然气40Ar/36Ar组成,柯克亚油气田的气源不是单一来源;柯克亚油气田绝大多数天然气的甲烷和乙烷碳同位素值关系符合Faber推断的 型有机质方程直线关系,说明有机质属于较好的有机质类型,或者是由原油裂解形成的天然气;除了K2井和K18井天然气成熟度较低以外,绝大多数天然气的成熟度大约在1.8%～2.2%之间,属于高过成熟气,但也混有一些成熟度在0.9%～1.2%的源岩形成的天然气;推测天然气主要来源于石炭系―二叠系源岩,而混有成熟度低的源岩形成的天然气则有可能来自侏罗系源岩。