An exciplex-halogen high-frequency radiation source on mixtures of krypton and xenon with chlorine molecules

The results of optimization of a broadband ultraviolet (UV) radiation source, which is excited with a transverse radio-frequency low-pressure discharge with a planar aperture, are presented. The UV source operates on Kr-Cl₂ and Kr-Xe-Cl₂ working mixtures. The UV source operates on the system of electron vibrational bands of XeCl* and KrCl* exciplex molecules and chlorine molecules in the spectral range 210–310 nm. The average radiation power reaches 30–50 W at an efficiency of 10–15%.     

An electrochemical methanol actinometer and its application to measurements of the intensity of vacuum UV radiation of a Xe 2 * excilamp

A methanol actinometer is used for measuring the intensity of vacuum UV radiation of a Xe ₂ ^* excilamp. The absorbed radiation dose is determined by measuring the concentration of formaldehyde, which is the decay product of methanol illuminated by UV radiation, with the use of amperometric titration.     

Vibration of a steam turbo-generator (TG) set during shutdown period

The steam turbo-generator (TG) sets in power plants during the shutdown period often operate at a very low speed with the aid of barring gear. This low speed is known as the barring speed and it is of the order upto 100 RPM. The purpose is to float the rotor in the fluid bearings so that the rotor heavy self-weight should not cause any damage to the bearings. The barring speed also maintains uniformity of temperature across the complete rotor when cooling down from operating condition to normal condition. Operating at the barring speed is often considered as the machine is close to the stand still condition and may not be subjected to any harsh vibration problem. However the in-situ vibration measurement on a typical steam TG set during machine shutdown operating at the barring speed reveals that the machine is subjected to vibration which may have potential to propagate the existing damage further. The paper presents a typical industrial case study and observations.     

Probing the role of C+ ion energy,thickness and graded structure on the functional and microstructural characteristics of ultrathin carbon films (<2 nm)

We report a comprehensive study on the protective, functional and microstructural properties of filtered cathodic vacuum arc (FCVA) deposited ultrathin carbon overcoats (COCs), which are being considered as potential candidates for future media recording technology such as heat-assisted magnetic recording (HAMR). Specifically, the influence of the C⁺ ion energy (50–345 eV) and the film thickness (0.5–3.2 nm) on these properties were investigated and supported with Raman and X-ray photoelectron spectroscopy (XPS). Finally, an optimized deposition recipe has been proposed to develop an ultrathin (≤2.0 nm) yet continuous COC with improved wear and corrosion resistance compared to thicker conventional COCs (~2.7 nm).     

An investigation of the influences of noise on EEG power bands and visual cognitive responses for human-oriented product design

Various different human-oriented approaches are required in industrial activities. Noise is one of the most widespread sources of environmental stress. So, it is important to consider noise when we design human-oriented products. This study investigates the responses of EEG and eye movement data in order to evaluate the direct effects of low, middle, and high frequency noise on the two main physiological stress aspects: the EEG band power (alpha and beta frequency bands) and pupil response time (PRT) for a human-oriented product design. Fifteen subjects were exposed to low (100 Hz), middle (1000 Hz), and high frequency (10000 Hz) noise while awake. EEG and eye movement data were collected during noise exposure. Alpha band activity in low and high frequency noise ranges was smaller than that in no sound. Alpha band activity decreased 19.3 ± 4.5 % in the low frequency noise range. Additionally, alpha band decreased 19.5 ± 5.4% in high frequency noise range. On the other hand, Beta band activity in low and high frequency noise ranges was greater than that in no sound. Beta band activity increased 26.9 ± 7.9 % in the low frequency noise range and increased 30.6 ± 6.1% in high frequency noise range. The PRT, or visual cognitive responses, in low or high frequency noise was greater than that in no sound. PRT increased 15.3 ± 3.0% in low frequency noise range. Alternatively, PRT increased 18.1 ± 3.2% in high frequency noise range. And results of EEG and eye movement were statistically significant in low and high frequency noise (r > 0.92, p < 0.05). The findings of this study indicate that the stress induced by low frequency noise is as stressful as the stress induced by high frequency noise. Additionally, utilizing eye movement data and acquiring the PRT is useful in the analysis of human stress responses during various stressful situations in addition to the analysis of human stress responses during noise exposure.     

Optimization of forming steps in the incremental forming of twisted shapes using a line array roll set (LARS)

The line array roll set (LARS) process is an effective metal forming process used to manufacture doubly curved metal plates. This study describes process optimization of forming steps that can be used to form a twisted shape. In the incremental forming of a twisted shape using the LARS process, a defect near the edge of the formed shape was observed. A plate was subjected bending and twisting simultaneously by the roll sets as part of this process; therefore, it was assumed that the edge defect resulted from the excessive longitudinal strain near the edge region of the plate. To obtain a desired shape with more precision and to minimize any possible defect, the process of forming the desired shape should be systematically and accurately designed. To obtain the optimized design and to ensure that the maximum longitudinal strain is under the limit of the critical value, an iteration scheme is used for the optimization. Edge profiles of deformed shapes for both a non-optimized design and an optimized design were compared. From the comparison, it was found that the optimized design can minimize the number of forming steps by decreasing the edge wave caused by excessive edge stretching.     

(2PRR)~2+R平面并联机构的刚度与固有频率

基于两移动一转动三自由度平面并联机构构造了一种新型五自由度串并混联机器人并对其并联部分,一具有运动冗余和驱动冗余两种不同模式的平面并联机构(2PRR)~2+R进行了运动学分析。首先,建立了三自由度平面并联机构的运动学模型,基于机构的运动学模型推导得到了冗余和非冗余驱动并联机构的刚度矩阵,并且通过求取并联机构各组成构件的等效质量,得到并联机构的质量矩阵;然后,借助系统刚度矩阵和质量矩阵建立的并联机构动力学方程,求得了机构的固有频率方程;最后,通过数值仿真对冗余和非冗余驱动并联机构的刚度及固有频率进行对比分析。结果显示:冗余驱动分支对机构绕Z轴方向角刚度和系统的一阶固有频率均值影响最大,其增幅分别为88.46%和31.50%;对X轴方向的线刚度和系统的二阶固有频率均值影响最小,其增幅分别为52.34%和1.90%。因此,冗余驱动分支有助于提高并联机构的整体刚度,改善机构的动态性能。     

泰国农业机械化考察报告(续)

三、泰国农机生产企业的有关情况在泰国方面的安排下,考察团还参观了马永兴拖拉机两合公司(生产手扶拖拉机)、李松兴机器有限公司(生产果品烘干设备)、库那星机器有限公司(生产粉碎机等小型机具设备)、卡萨德脱粒机厂、卡萨德水稻联合收割机厂等5个有代表性的农机生产企业.这些农机生产企业的规模、条件、生产能力、技术水平各不相同.水稻联合收割机、脱粒机的情况相对较好,较为接近目前我国同类机具的生产状况,而手扶拖拉机、粉碎机、烘干机等其他小型农机具则相对较为落后,和我国目前的农机生产情况相比,尚有较大的差别.     

Polymorphism of a long-chain cycloparaffin (CH2)120.

The polymorphism of a long-chain cycloparaffin (CH2)120 and chain packing in its crystals were discussed on the basis of some results obtained mainly by transmission electron microscopy. Monoclinic and orthorhombic single crystals of (CH2)120 were isothermally grown together from a dilute solution in p-xylene. Lozenge-shaped orthorhombic single crystals were more frequently observed than lath-shaped monoclinic ones. The basal surfaces of orthorhombic and monoclinic single crystal platelets were decorated with vapor-deposited polyethylene [PE]. Orthorhombic single crystals of (CH2)120 with the (110) twin boundary and monoclinic ones with the (100) twin boundary were also observed. Rod-like edge-on crystals of (CH2)120 were grown from a dilute p-xylene solution onto the (001) surface of alkali halides. The crystal system of the (CH2)120 edge-on crystals depended on the kind of substrate. The monoclinic crystal was grown on NaCl, the orthorhombic one on KBr and KCl. The monoclinic form of (CH2)120 edge-on crystal was transformed to the orthorhombic one by annealing on NaCl. In both monoclinic and orthorhombic edge-on crystals, the molecular plane determined by two zigzag stems in a molecule of (CH2)120 was parallel to the substrate surface and the molecular axis (crystallographic c-axis) was perpendicular to the longer side of the rod-like edge-on crystals. The sub-cell dimensions of the stem chains in both forms of (CH2)120 crystals were very similar to those of monoclinic and orthorhombic PE crystals, respectively.     

Experimental approached optimisation of a linear motion performance with grey hazy set and Taguchi analysis methods (GHST) for ball-screw table type

In end effect to control a path, tracking, or cutting motion of CNC milling machine or other applications of machine tools, controlling its actuator, specifically a linear table motion, becomes a classical matter to be solved in industries. By applying an optimisation of grey hazy set Taguchi (GHST) analysis methods, it might get a performance improvement of a linear motion of ball-screw table type. In this paper, it is aimed to enhance on multi-performance characteristics, namely, displacement, velocity and torque. An improvement of an average error of position accuracy is from the 0.2100 to 0.0137 mm (S/N ratio from 13.4023 to 37.1935 dB). Average error of position time is significantly improved from 0.1599 to 0.0293 s (S/N ratio from 15.9229 to 29.9305 dB). The average error of torsion standard deviation from 0.0924 Nm is improved to 0.0481 Nm (S/N ratio from 20.5970 to 26.3447 dB). This study indicated that GHST analysis approach might be applied successfully to table motion performance optimisation, which is determined by many parameters at multi-quality performances.     

Effect of radiation dose on depth-dependent oxidation and wear of shelf-aged gamma-irradiated ultra-high molecular weight polyethylene (UHMWPE)

The effect of radiation dose on the depth-dependent oxidation and wear of shelf-aged gamma-irradiated UHMWPE was investigated in this paper. FTIR, micro-indentation, pin-on-plate wear tests and SEM imaging were carried out at three representative regions (surface, subsurface and center) for each sample. The experimental results show that when the oxidation index (OI) <1, the wear rate is clearly affected by the radiation dose (crosslinking density). When 1<OI<3, the wear rates are mainly controlled by the OI. When OI>3 – except for the 1000 kGy specimen – the wear resistance is severely deteriorated and the relationship with the radiation dose is difficult to predict. Results suggest that higher irradiation (above 200 kGy) is capable of lowering the oxidative degradation of UHMWPE.     

Effect of Helicobacter pylori eradication on cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS) expression during gastric adaptation to aspirin (ASA) in humans

Gastric adaptation to aspirin is impaired in Helicobacter pylori infection, but the mechanisms underlying this phenomenon are unclear. In this study, we compared gastric mucosal expression of iNOS and COX-2 during 14 days of aspirin ingestion in the same subjects before and 3 months after eradication of H. pylori. Compared to non-infected controls, mucosal expression of COX-2 and iNOS was enhanced before and 3 months after eradication of H. pylori. During aspirin ingestion, mucosal expression of COX-2 remained unchanged before eradication of H. pylori, but increased gradually after successful antimicrobial treatment. Independent of H. pylori status, expression of iNOS increased at the beginning of aspirin intake, but then returned to initial values. We conclude that COX-2 but not iNOS might be involved in gastric adaptation to aspirin in humans and that this mechanism appears to be impaired in H. pylori infection.     

超精密研磨技术及其发展的研究(下)

阐述超精密研磨技术的研磨机理和加工特点,讨论当前国内外研究和开发的几种超精密研磨技术及其发展.最后,介绍精密加工技术的检测设备和仪器.     

New laser setup for the selective isotope production and investigation in a laser ion source at the IRIS (Investigation of Radioactive Isotopes on Synchrocyclotron) facility

New laser installation for the resonance ionization spectroscopy in a laser ion source and for rare isotope production has been recently put into operation at the IRIS (Investigation of Radioactive Isotopes on Synchrocyclotron) facility (Petersburg Nuclear Physics Institute, Gatchina). This is a significant improvement of a previous target-laser ion source device of the IRIS mass-separator, working on-line with 1 GeV proton beam of PNPI (Petersburg Nuclear Physics Institute) synchrocyclotron. It makes possible for us to get the isobarically clean radioactive isotope beams of a great number of chemical elements. New laser setup provides the two- or three-resonance step ionization in the range of wavelength of 265-850 nm. The first results obtained at the laser setup for Tl isotopes are presented.     

The differential reactivity of octahydridosilsesquioxane on Si(100)-2x1 and Si(111)-7x7: a comparative experimental study

Scanning tunneling microscopy (STM), in conjunction with X-ray photoemission (XPS) and reflection-absorption infrared (RAIRS) spectroscopy, has been used to investigate the reaction of octahydridosilsesquioxane clusters (H(8)Si(8)O(12)) on the Si(100)-2x1 and Si(111)-7x7 surfaces. The clusters exhibit a markedly different reactivity upon exposure to the two clean silicon surfaces. STM data is presented that, in conjunction with XPS and RAIRS data, provides numerous constraints upon possible geometries for the chemisorbed clusters. The sum of the data is consistent with a dissociative reaction mechanism on Si(100)-2x1, resulting in cluster attachment to the surface via a single vertex. Conversely, data of Si(111)-7x7 subject to a saturation exposure of H(8)Si(8)O(12) is presented that is highly suggestive of cluster decomposition on the surface.     

Development and characterization of a new nickel(II) ion selective optode based on 2-amino-1-cyclopentene-dithiocarboxylic acid

A highly sensitive and selective optical membrane sensor was prepared for the determination of ultra trace amount of Ni²⁺ ions. The plasticized PVC membrane incorporating dibuthylphthalate and 2-amino-1-cyclopentene-dithiocarboxylic acid (ACDA) as a chromoionophore works on the basis of a cation-exchange mechanism and shows a significant absorbance signal change on exposure to acidic solution containing nickel(II) ion. The sensor displays a calibration response for Ni²⁺ ion over a wide concentration range of 3.1 × 10⁻⁸-8.0 × 10⁻³ M, and a response time of 3 min. In addition to high stability, reproducibility and relatively long working lifetime, the sensor possesses good selectivity for nickel(II) ion over several common diverse ions. The sensor was successfully applied to determine the traces of Ni²⁺ ion in some water samples.     

维生素D缺乏与2型糖尿病胰岛素抵抗关系及维生素D治疗2型糖尿病效果

目的 :分析2型糖尿病(T2DM)患者胰岛素抵抗(IR)与维生素D(VD)缺乏的关系,并观察VD对T2DM的治疗效果。方法 :选取我院2013年4月—2015年4月收治的100例T2DM患者,纳入T2DM组,随机分为VD治疗组及常规治疗组各50例,均使用降糖药口服治疗,VD治疗组加用维生素D口服。并选取同期100例健康体检者,纳入健康对照组。检测稳态模型胰岛素抵抗指数(HOMA-IR)、胰岛B细胞功能指数(HOMA-β),以25(OH)D为自变量,以HOMA-IR及HOMA-β为因变量,采用一元回归分析,分析胰岛素抵抗与VD水平的相关性;比较两组T2DM患者治疗前后血糖、胰岛素抵抗状态变化。结果 :T2DM患者组空腹血糖(FPG)、空腹胰岛素(FIns)、HOMA-IR显著高于健康对照组,其HOMA-β、25(OH)D显著低于健康对照组,差异有统计学意义(P<0.05)。VD水平与HOMA-IR呈显著负相关,VD水平与HOMA-β呈显著正相关。两组T2DM患者治疗后FBG、FIns、餐后2 h血糖(2 h PG)、糖化血红蛋白(Hb A1c)均显著下降,VD治疗组变化更为明显,与常规治疗组比较差异有统计学意义(P<0.05),VD组治疗后HOMA-IR显著下降,HOMA-β、25(OH)D均显著上升,与治疗前比较差异有统计学意义(P<0.05)。结论 :T2DM患者存在明显VD缺乏状态,VD水平与其胰岛B细胞功能呈正相关,补充VD有助于改善患者胰岛素抵抗状态,取得更好的血糖控制效果。     

CrB2(0001)表面特性和电子结构的第一性原理研究

基于第一性原理的密度泛函平面波赝势方法,对两种不同终端CrB2(0001)的表面性能:表面弛豫、表面能和电子结构等进行了计算和分析.当CrB2(0001)表面结构原子层数达到9时,表面层间距快速收敛.通过分析差分电荷密度和态密度(PDOS),可以得出硼终结CrB2(0001)表面结构比铬终结CrB2(0001)具有较小的界面能和较强的电子相互作用,表面更稳定.