基于功能磁共振成像方法的单相抑郁症情绪加工特点研究

运用功能磁共振成像(fMRI)技术,采用适合中国人情绪加工特点的表情图片(愉快、悲伤和中性表情)作为刺激材料,选取15名严格入组的未服药单相抑郁症女性患者与15名条件匹配的正常志愿者,对其情绪加工的大脑活动进行了对比研究。结果发现,与中性表情相比,在加工愉快表情时,抑郁症患者激活了右侧前额叶,而正常对照组激活的是左侧前额叶;在悲伤表情条件下,抑郁症患者激活了双侧颞下回,而正常对照组激活的是双侧前额叶。结果还发现,与正常对照组相比,抑郁症患者在双侧额下回三角区、右侧眶额下回、右侧颞下回等脑区的激活范围和强度均有所减少,尤其在加工悲伤表情时表现得更明显。该结果表明,单相抑郁症病人不仅在情绪加工相关脑区的功能上出现异常,而且加工情绪的脑区也可能出现了转移。     

Enzyme-Triggered Transforming of Assembly Peptide-Modified Magnetic Resonance-Tuned Probe for Highly Sensitive Imaging of Bacterial Infection In Vivo

Confirming bacterial infection at an early stage and distinguishing between sterile inflammation and bacterial infection is still highly needed for efficient treatment. Here, in situ highly sensitive magnetic resonance imaging (MRI) bacterial infection in vivo based on a peptide-modified magnetic resonance tuning (MRET) probe (MPD-1) that responds to matrix metallopeptidase 2 (MMP-2) highly expressed in bacteria-infected microenvironments is achieved. MPD-1 is an assembly of magnetic nanoparticle (MNP) bearing with gadolinium ion (Gd³⁺) modified MMP-2-cleavable self-assembled peptide (P₁) and bacteria-targeting peptide (P), and it shows T₂-weighted signal due to the assemble of MNP and MRET ON phenomenon between MNP assembly and Gd³⁺. Once MPD-1 accumulates at the bacterially infected site, P₁ included in MPD-1 is cleaved explicitly by MMP-2, which triggers the T₂ contrast agent of MPD-1 to disassemble into the monomer of MNP, leading the recovery of T₁-weighted signal. Simultaneously, Gd³⁺ detaches from MNP, further enhancing the T₁-weighted signal due to MRET OFF. The sensitive MRI of Staphylococcus aureus (low to 10⁴ CFU) at the myositis site and accurate differentiation between sterile inflammation and bacterial infection based on the proposed MPD-1 probe suggests that this novel probe would be a promising candidate for efficiently detecting bacterial infection in vivo.     

The effect of some heat treatment parameters on the dimensional stability of AISI D2

The tool steel AISI D2 is usually processed by vacuum hardening followed by multiple tempering cycles. It has been suggested that a deep cold treatment in between the hardening and tempering processes could reduce processing time and improve the final properties and dimensional stability. Hardened blocks were then subjected to various combinations of single and multiple tempering steps (520 and 540 °C) and deep cold treatments (−90, −120 and −150 °C). The greatest dimensional stability was achieved by deep cold treatments at the lowest temperature used and was independent of the deep cold treatment time.     

The effect of pre-straining on the mechanical behaviour of self-piercing riveted aluminium alloy sheets

Self-piercing riveting as an alternative joining method to spot-welding has attracted considerable interest from the automotive industry and has been widely used in aluminium intensive vehicles. Pressing and stamping are important processes in automotive production and result in additional straining on the vehicle body sheet material. It is therefore important to have knowledge of the effect of sheet pre-straining on the quality of the self-piercing riveted joints and on the mechanical behaviour of the riveted aluminium alloy sheets. This paper reports the influence of sheet pre-straining on the static and fatigue behaviour of self-piercing riveted aluminium alloy sheet. Wrought aluminium alloy sheet, NG5754 with a nominal thickness value of 2 mm was used to obtain pre-strained NG5754 sheets with pre-straining levels of 3%, 5% and 10%. Pairs of pre-strained NG5754 sheets were joined to create single-riveted lap joints which subsequently underwent lap-shear and fatigue testing. Microscopic inspection showed that the joint quality was satisfactory despite the increasing sheet straining levels. The results showed that by increasing the pre-straining level up to 10%, the shear and fatigue strength also increased. The rate of increase of the static and fatigue strength differed as the pre-straining levels varied.     

Production, modification and bio-applications of magnetic nanoparticles gestated by magnetotactic bacteria

Magnetotactic bacteria (MTB) were first discovered by Richard P. Blakemore in 1975, and this led to the discovery of a wide collection of microorganisms with similar features i.e., the ability to internalize Fe and convert it into magnetic nanoparticles, in the form of either magnetite (Fe₃O₄) or greigite (Fe₃S₄). Studies showed that these particles are highly crystalline, monodisperse, bioengineerable and have high magnetism that is comparable to those made by advanced synthetic methods, making them candidate materials for a broad range of bio-applications. In this review article, the history of the discovery of MTB and subsequent efforts to elucidate the mechanisms behind the magnetosome formation are briefly covered. The focus is on how to utilize the knowledge gained from fundamental studies to fabricate functional MTB nanoparticles (MTB-NPs) that are capable of tackling real biomedical problems.     

一种新型的掩膜管理控制系统的研制

研制了一种与掩膜光刻机相配套的新型掩膜管理控制系统.系统硬件由1个4自由度机械手、2个版库、粗预对准机构、精细预对准机构、PLC控制器和伺服驱动器等构成;系统软件由基于VC的上层管理程序以及基于梯形图的底层流程控制程序构成,其中上掩膜版和卸掩膜版是流程控制的主要组成部分.介绍了四象限光电探测器的对准工作原理和掩膜版的粗、精细预对准方法,实验测试了上、卸掩膜版的节拍,粗、精细预对准时间和掩膜版经过精细预对准后的重复定位精度,讨论了激光器和四象限光电探测器相对 位姿的标定方法,并指出了该系统的特点.实验结果表明,该系统性能稳定,主要指标能够满足掩膜光刻机的实际生产要求.     

Fabrication of gradient material by electron beam smelting based on scanning track control

A new electron beam (EB) control system was developed in a general vacuum EB machine by equipping it with an industrial control computer, programmable logic control (PLC), deflection coil, data acquisition card, power amplifier, etc. In this control system, the scanning track and energy distribution of the EB could be edited off-line, adjusted in real-time, and controlled on-line. Ti-Mo gradient material (GM) with high temperature resistance was fabricated using electron beam smelting (EBS) control. The smelting pro cesses include three steps such as preheating, smelting, and homogenizing. The results show that GM prepared by using smelting technology has fine appearance, and has good integrated interface with Ti alloy. The Mo and Ti elements are gradual diversification in the interface of the gradient material. The microstructure near the Ti alloy base metal is α+β basket-waver grain, and the microstructure near GM is single phase of β solid solution.     

Preparation and characterization of a novel hyperbranched polyphosphate ester

Polyphosphate esters have received a great deal of attention due to their important application in biomaterials field. Hyperbranched structure of polymers may support unique properties, including low viscosity and perfect intrinsic property. We report here three generations of hyperbranched polyphosphate esters (HPPE-1, HPPE-2 and HPPE-3) synthesized from a dehydrochlorination reaction between 1,3,5-tris(2-hydroxyethyl)cyanuric acid (THEIC) and phosphorus oxychloride (POCl₃), and characterize their chemical structures by FT-IR, ¹H NMR, ¹³C NMR, ³¹P NMR and 2D NMR (¹H,¹H-COSY and ¹³C, ¹H-HSQC) techniques. Degrees of branching of HPPE-1, HPPE-2 and HPPE-3 are 0.90, 0.91 and 0.87 respectively from the calculation of their ¹³C NMR spectra. Molecular weights of HPPE-1, HPPE-2 and HPPE-3 are m/z 1530, 1768 and 2750 from their MALDI-TOF-MS spectra. Study on thermal degradation mechanism of the HPPE-2 by a 3D FT-IR/TG technology shows that there are two cracking processes of its molecular chains, including the thermal degradation of hydroxylethyl-ended groups, nitrogen heterocycle and –CH₂CH₂– groups of HPPE-2.     

Physical properties and MAS-NMR studies of titanium phosphate-based glasses

In this study, for a series phosphate-based glasses ((P₂O₅)_0.45(CaO)_0.3(Na₂O)_0.25−x(TiO₂)_x, 0 ≤ x ≤ 0.15), their degradation, ion release, surface and thermal properties have been determined. The results show that adding TiO₂ was associated with a significant increase in density and glass transition temperature, but a decrease in degradation rate and ion release. ³¹P solid-state magic-angle-spinning nuclear magnetic resonance (MAS-NMR) showed that the local structure of the glasses changes with increasing TiO₂ content. As TiO₂ is incorporated into the glass, the phosphate connectivity increases as Q¹ units transform to Q², confirming that an increase in the nominal TiO₂ content correlates unequivocally with an increase in glass stability. As reported for titania–silica gels, Ti⁴⁺ is clearly adopting a network former role in these phosphate-based glasses. ²³Na MAS-NMR results corroborate this phenomenon with a marked upfield trend of the ²³Na isotropic chemical shift suggesting that the local Na–O bond distances are decreasing within a more condensed glass network upon increased incorporation of TiO₂.     

On-line tuning system of multivariate dEWMA control based on a neural network approach

The double exponentially weighted moving average (EWMA) controller is a popular algorithm for on-line quality control of semiconductor manufacturing processes. The performance of the closed-loop system hinges on the adequacy of the two weight parameters of the double EWMA equations. In 2004, Su and Hsu presented an approach based on the neural technique for ‘on-line’ tuning the weight of the single EWMA equation in the single-input single-output (SISO) system. The present paper extends the neural network on-line tuning scheme to the double EWMA controller for the non-squared multiple-input multiple-output (MIMO) system, and validates the control performance by means of a simulated chemical–mechanical planarization (CMP) process in semiconductor manufacturing. Both linear and non-linear equipment models are considered to evaluate the proposed controller, coupling with the deterministic drift, the Gaussian noise and the first-order integrated moving average (IMA) disturbance. It has been shown from a variety of simulation studies that the proposed method exhibits quite competitive control performance as compared with the previous control system. The other merit of the proposed approach is that the tuning system, if sufficient training in a neural network is available, can be practicably applied to complex semiconductor processes without undue difficulty.     

The effect of deposition parameters on the properties of yttria-stabilized zirconia thin films

Yttria-stabilized zirconia (YSZ) films were deposited by RF magnetron sputtering in order to examine the effects of sputtering conditions on the properties of the resulting thin-films. X-ray diffraction (XRD), Rutherford backscattering spectroscopy (RBS) and scanning electron microscopy (SEM) were used to characterize the films. Additionally, films were deposited on alumina bars to examine the effect of the coatings on the strength of a brittle substrate. RBS analysis indicated that the ratio of oxygen to zirconium in the films varied from 1.84 to 2.10. XRD showed that there was a wide variation in the amount of monoclinic and tetragonal phases that appeared to be related to the O:Zr ratio. Despite these variations, there was no significant difference found in flexural strength found among the groups of alumina bars that were coated with YSZ. The likely cause is the columnar grain morphology of the deposited thin-films, which does not allow strengthening mechanisms to become operative.     

The effect of temperature and polymer concentration on dynamic surface tension and wetting ability of hydroxypropylmethylcellulose solutions

The purpose of the present study was to evaluate quantitatively the changes of dynamic surface tension and contact angle of hydroxypropylmethylcellulose (HPMC) aqueous solutions as a function of temperature and polymer concentration of the examined solutions. HPMC aqueous solutions of different concentrations (1%, 2%, 3%, 4% w/w) were prepared without plasticizer and with 1% w/w Lutrol F127. Dynamic surface tension of the prepared solutions was determined by the Du Nouy ring method of the KSV Sigma 70 computer-controlled and programmable tensiometer. The dynamic contact angle of Avicel PH-101 tablets was measured against HPMC solutions of various concentrations by the plate method of the KSV Sigma 70 tensiometer. The obtained results indicate that dynamic surface tension measurement can be applied for the accurate determination of the thermal gelation temperature of the prepared HPMC solutions. With increasing concentration of HPMC, dynamic contact angle values of solutions also increased, thus decreasing the spreading behavior on the surface of Avicel tablets.     

A review of production planning and control: the applicability of key concepts to the make-to-order industry

The paper reviews ‘classic approaches’ to Production Planning and Control (PPC) such as Kanban, Manufacturing Resource Planning (MRP II) and Theory of Constrains (TOC), and elaborates upon the emergence of techniques such as Workload Control (WLC), Constant Work In Process (CONWIP), Paired cell Overlapping Loops of Cards with Authorization (POLCA) and web- or e-based Supply Chain Management (SCM) solutions. A critical assessment of the approaches from the point of view of various sectors of the Make-To-Order (MTO) Industry is presented. The paper considers factors such as the importance of the customer enquiry stage, company size, degree of customization and shop floor configuration and shows them to play a large role in the applicability of planning and control concepts. The paper heightens the awareness of researchers and practitioners to the PPC options, aids managerial system selection decision-making, and highlights the importance of a clear implementation strategy. WLC emerges as the most effective Job Shop solution; whilst for other configurations there are several alternatives depending on individual company characteristics and objectives. The paper outlines key areas for future research, including the need for empirical research into the use of Workload Control in small and medium sized MTO companies.     

考虑涡旋效应的圆柱形TLD多维减震效果研究

调谐液体阻尼器可以控制地震作用下的结构动力响应。研究了利用圆柱形调液阻尼器来控制结构在地震作用下的扭转耦联振动。采用薄膜法建立了包含脉冲动压力和对流动压力的调谐液体阻尼器液动压力模型。基于准均匀涡旋理论获得了考虑调谐液体的抗扭力模型。建立了考虑偏心扭转效应的结构控制运动方程。以一装有调谐液体阻尼器的偏心结构为算例,对结构在地震作用下的扭转耦联减震效果进行研究,并分析了调谐液体的脉冲动压力、对流动压力和涡旋抗扭力在减震中的作用。结果表明：合理布置的调液阻尼器能有效控制结构的平-扭耦联振动,不能忽略液体涡旋产生的扭转力。     

Ethyl acetoacetate ligand distribution in the course of titanium n-butoxide chelation

Sols obtained by chelation of titanium n-butoxide with ethyl acetoacetate, Eaa, in various ratios have been subjected to FTIR, ¹H and ¹³C NMR, HSQC and UV–Vis spectroscopy in order to provide insight in the compounds obtained, their structure and quantitative relationships. Three compounds, the bis-chelated monomer, Ti(OⁿBu)₂(Eaa)₂, bis-chelated dimer, (Ti(OⁿBu)₃Eaa)₂ and monochelated dimer, Ti₂(OⁿBu)₇Eaa have been established. As the molar ratio Eaa/Ti(OⁿBu)₄ increases, the coordination changes from the monochelated and bis-chelated dimer to the bis-chelated monomer. Additionally, the transesterification reaction, influencing the chemical composition of the compounds was noted. The hydrolysis of the prepared sols was partial, leaving some residual butoxy and ethyl acetoacetate groups attached to titanium. Thermal treatment of the prepared amorphous gels at 350 °C yielded with the formation of nanocrystalline anatase. It was noted that high Eaa/Tnb ratio slightly retards the anatase formation.     

The effect of copper ions on interaction of UV radiation with methacrylic matrix – EPR study

The role of metal ions introduced to polymer matrix in the photochemical degradation of material is not fully understood. In this paper, we considered the effect of copper ions on the photochemical changes in Methafilcon A after UV-irradiation. The presence of methacrylic acid in the structure of Methafilcon A increases the loading capacity of these ions. In result, there is observed the production much more radicals after UV-irradiation than in pure matrix, without copper ions. When the time of UV-exposure increases, the EPR signal of trapped Cu(II) ions in the material decreases. This proves the transformation of Cu(II) to a diamagnetic state of stable Cu(I)-intermediates or copper oxides. Simultaneously, in the first 5-min of UV-irradiation there is observed a rapid increase in intensity of the radical signal, which disappears when the exposure time is extended. This mechanism of radical generating is quite different than for Methafilcon A matrix without copper ions.     

The effect of annealing on single-layer CoCrPtNb thin films

The effect of Nb addition on grain size segregation and intergranular coupling of ternary CoCrPt alloys prepared by annealing of crystalline samples and crystallization of the Nb-rich (more than 4.6 at.%) amorphous films is investigated. Mean surface roughness as a function of Nb addition decreased for Nb contents of up to 2.7 at.% and then increased. The size and distribution of magnetic clusters were significantly affected by Nb addition. Vacuum annealing of the ternary and quaternary films (2.7 at.% Nb) increased the coercivity of the films from 53.71 kA/m and 52.09 kA/m to about 61.14 kA/m and 105 kA/m, respectively. Film with 12.1 at.% Nb was also produced and then annealed at different times and temperatures. Increasing the temperature to 700 °C caused the recrystallization of the 12.1 at.% Nb amorphous film. The observed magnetic properties are discussed in terms of composition, crystallographic orientation of deposited layer and oxidation of elements during annealing.     

Hierarchical fuzzy segmentation of brain MR images

In brain magnetic resonance (MR) images, image segmentation and 3D visualization are very useful tools for the diagnosis of abnormalities. Segmentation of white matter (WM), gray matter (GM), and cerebrospinal fluid (CSF) is the basic process for 3D visualization of brain MR images. Of the many algorithms, the fuzzy c‐means (FCM) technique has been widely used for segmentation of brain MR images. However, the FCM technique does not yield sufficient results under radio frequency (RF) nonuniformity. We propose a hierarchical FCM (HFCM), which provides good segmentation results under RF nonuniformity and does not require any parameter setting. We also generate Talairach templates of the brain that are deformed to 3D brain MR images. Using the deformed templates, only the cerebrum region is extracted from the 3D brain MR images. Then, the proposed HFCM partitions the cerebrum region into WM, GM, and CSF. © 2003 Wiley Periodicals, Inc. Int J Imaging Syst Technol 13, 115–125, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.10035     

The effect of copper granules on interfacial bonding and properties of the copper-graphite composite prepared by flake powder metallurgy

The study evaluates the effect of introducing Cu granules and control milling on the microstructure, interfacial bonding and mechanical properties including sintered density, hardness, compressive strength, flexural strength and electrical conductivity of Copper-Graphite (Gr) composite synthesize by flake powder metallurgy (Flake PM). It develops the flake composite particles by control mechanical alloying (MA) which further laminates over the refine granules surface. This encapsulation facilitates the strong interfacial bonding among the composite constituents during sintering. Results highlight that the 10% Cu granules in Cu-10Gr composite exhibit excellent mechanical properties. It increases the relative density, hardness, compressive strength, and flexural strength by 4.19%, 28.23%, 98.31%, and 11.8% respectively. However, the electrical conductivity increases by 6.73% (%IACS) for 15% of Cu granules in the Cu-10Gr composite. The improvements in the results are the synergistic coordination of dispersion homogeneity, surface integrity, work hardening, and the superior interfacial adhesion between composite powder and Cu granules.     

Ni定位掺杂4H-SiC(001)磁性与光学性质的研究

采用基于密度泛函理论的第一性原理研究了4H-SiC(001)定位掺杂Ni的磁性,结果表明相对于掺杂前表面悬挂键的存在使体系具有弱磁性,Ni定位取代Si位置后得到的体系更加稳定。对比分析了Ni定位取代不同数量的C与Si原子后,得出取代C原子比取代Si原子得到的磁矩大,而且奇数倍的取代较偶数倍取代得到的磁矩大。定位取代一个C与一个Si比单独取代一种原子得到的磁矩大,因此从稳定性与磁性方面考虑C与Si同时取代是最好的掺杂选择。在导电性方面,随着Ni掺杂原子数量增加光电导相应增加。