Improved Circularity Metrology of Small Cylindrical Workpieces by the Segmenting-stitching Technique

To address the alignment and measuring force problem in the segmenting-stitching technique for the circularity metrology of small cylindrical workpieces(diameter less than 1.5 mm and length less than 10 mm),a magnet combination jig method is proposed.A small round magnet is attached between the round magnetic jig and small cylinder,and the other end of the small cylindrical workpiece is attached to some cylindrical magnets.Thus,the smaller cylinder can be put in the V-groove and measured successfully with the magnet combination.For verifying the advantage of the magnet combination jig,four measurement quality evaluations are proposed:the circumferential deviation of neighbor arc contours,radial deviation of neighbor arc contours,angle of inclination between the V-groove and small cylinder,and curvature of the obtained arc.The results show that the matching coefficient is enhanced by 98%,the Euclidean distance of overlap parts of neighbor arc contours is reduced by 68%,the position error is reduced 27%,and the average curvature of the arc contours is improved.It can be concluded that the measuring quality can be enhanced prominently by this magnet combination method for the segmenting-stitching method.

大鼠脊髓损伤后GFAP、cPLA2的表达变化及相关性研究

目的研究大鼠脊髓半横断损伤后胶质纤维酸性蛋白(glial fibrillary acidic protein,GFAP)和胞浆型磷脂酶A2(cytosolic phospholipase A2,cPLA2)的表达与分布,并分析其相关性,探讨两者在脊髓损伤后表达的意义和可能的内在关系。方法 30只SD大鼠随机分为脊髓损伤组(1、3、7、14和21 d)与假手术组,脊髓损伤组用T10节段半横断法(右侧)造模,而假手术组只行椎板切除不损伤脊髓。在各时间点取材后用尼氏染色观察脊髓组织病理学改变,采用免疫组织化学法检测脊髓组织GFAP与cPLA2表达,并经Motic Images Advanced软件处理后进行Pearson相关性分析。结果尼氏染色示脊髓损伤后神经元坏死,肿胀,空泡形成,形态不完整。免疫组织化学法示脊髓损伤后可见GFAP与cPLA2表达均增高,其中GFAP在各时间点表达逐渐增多,cPLA2表达在损伤后14 d达到高峰,GFAP与cPLA2阳性产物面积相关性分析提示其相关系数为0.74,差异无统计学意义(P=0.15),两者平均光密度值行相关分析后,相关系数为0.90,具有统计学意义(P=0.04)。结论大鼠脊髓损伤后GFAP与cPLA2表达均增多,且两者在损伤过程中表达具有相关性。

Computerized tomography based “patient specific blocks” improve postoperative mechanical alignment in primary total knee arthroplasty

AIM: To compare the postoperative mechanical alignment achieved after total knee arthroplasty(TKA) using computer tomography(CT) based patient specific blocks(PSB) to conventional instruments(CI).METHODS: Total 80 knees were included in the study, with 40 knees in both the groups operated using PSB and CI. All the knees were performed by a single surgeon using the same cruciate sacrificing implants. In our study we used CT based PSB to compare with CI. Postoperative mechanical femoro-tibial angle(MFT angle) was measured on long leg x-rays using picture archiving and communication system(PACS). We compared mechanical alignment achieved using PSB and CI in TKA using statistical analysis.RESULTS: The PSB group(group 1) included 17 females and seven males while in CI group(group 2) there were 15 females and eight males. The mean age of patients in group 1 was 60.5 years and in group 2 it was 60.2 years. The mean postoperative MFT angle measured on long-leg radiographs in group 1 was 178.23°(SD = 2.67°, range: 171.9° to 182.5°) while in group 2, the mean MFT angle was 175.73°(SD = 3.62°, range: 166.0° to 179.8°). There was significant improvement in postoperative mechanical alignment(P value = 0.001), in PSB group compared to CI. Number of outliers were also found to be less in group operated with PSB(7 Knee) compared to those operated with CI(17 Knee).CONCLUSION: PSB improve mechanical alignment after total knee arthroplasty, compared to CI. This may lead to lower rates of revision in the PSB based TKA as compared to the conventional instrumentation.

基于ObjectARX.Net的动态坐标标注

在工程制图的过程中,经常需要对图中的某些点进行坐标标注。如果仅是几个点来说手动标注工作量并不是很大,但如果需要的标注点较多时,不仅工作量较大,而且容易出错。基于ObjectARX.Net的AutoCAD二次开发技术,可以定制适合自己的坐标标注工具。通过ObjectARX.Net编程,定制适合自己的坐标标注工具,不仅能够满足自己的要求,还能提高工作效率,同时还具有灵活性。

基于ObjectARX.Net的Jig技术及其应用研究

论述了通过继承DrawJig类的所有方法、过程和事件,重载Sampler和WorldDraw函数,实现用户定制CAD互动命令的步骤和方法。详细介绍了动态坐标标注实例,通过DrawJig类控制拖动序列接受用户的选定坐标点,从而确定坐标标注各要素的标注位置,最后采用AddEntity函数向CAD数据库添加实体对象的方法实现了数字化成图软件中的动态标注功能。

A STUDY ON JIG DISTRIBUTION CURVE TRANSFORMATION

An investigation of the errors resulted from distribution curve transformations using six different methods was made on the basis of 61 sets of jig performance test data from the coal preparation plants in China. The results indicate that minimum error occurred when distribution curves were transformed by keeping imperfection I constant. Generalized distribution curves are developed for jigs and their applications are discussed.

微种植支抗联合Sliding jig推磨牙向后的临床研究

目的评价微种植支抗联合Sliding jig技术推磨牙向后的临床效果。方法选择2008年11月—2009年10月在浙江大学附属第一医院口腔科就诊的10例骨性Ⅰ类安氏Ⅱ类错患者,上颌拥挤度3～5mm,下颌正常或轻度拥挤,侧貌基本为直面型。在上颌第二前磨牙与第一磨牙之间的颊侧附着龈上植入微种植钉,在上颌尖牙的远中与第一磨牙的近中放置Sliding jig悬于主弓丝上,用橡皮链连接种植体与Sliding jig的近中端,加载2.94N的拉力,推磨牙向远中。对于治疗前后的模型和头颅侧位片进行比较分析。结果 10例患者均解除了拥挤,纠正了Ⅱ类磨牙关系。磨牙平均远中移动4.12mm,远中倾斜8.35°,垂直压低2.19mm,以上数据均有统计学意义(P<0.01)。磨牙平均颊向移动距离0.03mm(P>0.05)。中切牙舌向移动0.65mm(P>0.05)。结论微种植钉联合Sliding jig在推磨牙向后中发挥了绝对支抗的作用,前牙无唇倾,面型保持不变,值得临床推广。

On Jig's Psychological Changes in the Short Story Hills Like White Elephants of Hemingway

Hills Like White Elephants is a short story by Ernest Hemingway.It is a story about an American man and a pregnant girl.As the protagonist,Jig is considered as a submissive woman who has no definite views of her own.This paper attempts to analyze the changes of Jig's inner thought during the forty minutes of waiting the train.In addition to how the girl has grown up from a weak and dependent character into a brave and independent female after the painful struggle in the helpless and hopeless states under the great pressure of the man.

Recovery of coal particles from a tailing dam for environmental protection and economical beneficiations

Considerable amounts of coal particles are accumulated in the tailing dams of washing plants which can make serious environmental problems. Recovery of these particles from tailings has economically and environmentally several advantages. Maintaining natural resources and reducing discharges to the dams are the most important ones. This study was examined the possibility to recover coal particles from a tailing dam with 56.29% ash content by using series of processing techniques. For this purpose, gravity separation （jig, shaking table and spiral） and flotation tests were conducted to upgrade products. Based the optimum value of these processing methods, a flowsheet was designed to increase the rate of recovery for a wide range of coal particles. Results indicated that the designed circuit can recover over 90% of value coal particles and reduce ash content of product to less than 14%. These results can potentially be used for designing an industrial operation as a recycling plant and an appropriate instance for other areas to reduce the environmental issues of coal tailing dams.

The impact of spatial autocorrelation on CPUE standardization between two different fisheries

Catch per unit of eff ort(CPUE) data can display spatial autocorrelation. However, most of the CPUE standardization methods developed so far assumes independency of observations for the dependent variable, which is often invalid. In this study, we collected data of two fisheries, squid jigging fishery and mackerel trawl fishery. We used standard generalized linear model(GLM) and spatial GLMs to compare the impact of spatial autocorrelation on CPUE standardization for different fisheries. We found that spatialGLMs perform better than standard-GLM for both fisheries. The overestimation of precision of CPUE estimates was observed in both fisheries. Moran's I was used to quantify the level of autocorrelation for the two fisheries. The results show that autocorrelation in mackerel trawl fishery was much stronger than that in squid jigging fishery. According to the results of this paper, we highly recommend to account for spatial autocorrelation when using GLM to standardize CPUE data derived from commercial fisheries.

Estimation of Loose Status of Jigging Bed Based on Adaptive Neuro-Fuzzy Inference System

In the separation process with a jig washer, an accurate on-line measurement of loose status of a jigging bed is essential for a successful control of coal quality and loose status is difficult to measure on-line directly in industrial process situations. So a soft-sensor technology is needed for this purpose. The soft-sensor model is developed in the experiment by an adaptive neuro-fuzzy inference system （ANFIS） which has a remarkable ability of learning and generalization. Based on the analysis of the technologic mechanism of jigging bed, the structure of the ANFIS is established to build the soft-sensor model of loose status estimation. The ANFIS is trained by a hybrid learning algorithm. Finally, the simulation results and comparison analysis are presented, which indicate that the ANFIS has better abilities of learning and generalization than the RBF and the BP networks. Thus, it is possible that the loose status of the jigging bed can be estimated on-line bv using ANFIS.

Paste-like cemented backfilling technology and rheological characteristics analysis based on jigging sands

To make backfilling body meet strength requirement,physical-chemical evaluation and proportioning tests were conducted on several backfilling materials.Jigging sands,#32.5 cement and fly ash were determined as backfilling aggregate,binding material and modified material,respectively.An optimized proportion of backfilling materials with a solid mass fraction of 78%and cement:fly ash:jigging sands mass ratio of 1:2:14,was suggested to Jiangan Pyrite Mine,China.The slurry made by optimized proportion produced obvious shear thinning phenomena,and was confirmed as paste-like slurry.To analyze its rheological characteristics,L-type pipeline test and Haake VT550 rotational viscometer test were conducted.Bingham and Casson fluid models were applied to several paste-like slurry samples to simulate flow and stress states;Casson fluid model was proved to have better simulation effect on paste-like slurry with shear thinning phenomena;rheological parameters of backfilling slurry made by suggested proportion were measured.Initial yield stress,average apparent viscosity and limiting viscosity are 55.35 Pa,1.216 Pa-s and 0.48 Pa-s,respectively.Compared with Bingham fluid model,Casson fluid model has a better simulation effect on paste-like slurry with shear thinning phenomena,through calculating the residual standard deviations.

Performance analysis of jig for coal cleaning using 3D response surface methodology

Beneficiation of coal of -4.76 mm + 3 mm size fraction was investigated in a laboratory model Denver jig.Process variables were studied to analyze their effect on the performance of jig in terms of yield and ash content of clean coal. Three-factor three-level Box-Behnken design of experiments with response surface methodology(RSM) was employed to understand the performance behavior of jig. From the study, the bed height was found to be the most significant parameter affecting the yield and ash content of clean coal. It was possible to reduce the ash content from 24.32% in feed to an ash content of 16.55% in clean coal at 2 L/min water flow rate and 10 min jigging time. Influence of operating variables of the jig on responses was presented and discussed in 3D surface plots. The developed model was found to be significant within the range of parameters under investigation with correlation of co-efficient values as 0.99(yield) and 0.98(ash).

AutoCAD.NET的Jig技术在管线扯旗标注中的应用

在管线CAD系统中,经常会对管线进行扯旗标注,以用于地图打印、出图等。本文基于Auto CAD提供的.NET类型的API,在管线扯旗标注中采用Jig技术,实现标注过程的动态性交互,标注过程可动态预览。

Status Evaluation of Loose of Jig Bed Based on Fuzzy Inference System

This paper mainly describes that loose of jig bed affects jig's separation effect, and the corresponding fuzzy rules were built. Using the evaluating index of jig's separation effect--imperfection (I) and total misplaced material (Cz), it evaluates status of loose of jig bed by fuzzy inference system. Experimental simulation and applications in practice prove the method's feasibility.

Research on characteristics of water motion and influencing factors for the flexible air chamber jig body

The air bag deformation data were obtained by high-speed dynamic videos experiments. Based on gas–liquid flow VOF model, dynamic mesh technique and deformation data, numerical simulations for different structure models were achieved, and the law of water motion and influencing factors were analyzed.The results show that the flow in the length direction of the jig is smooth, and second pulsation appears in the separation time and forms the secondary separation. The installation position of screen and the number of air bags have a great influence on the uniformity of flow and velocity. The screen height cannot be too low to avoid forming the unstable flow. At the same time, the screen height cannot be too high, otherwise water velocity will be too small and was unable to provide enough power. At the height of 1.4m,velocity unevenness is minimum and the best uniform flow can be obtained. Compared with double air bags, there are the following features of single air bag: water flow is not smooth, the time achieving the maximum velocity is too long, maximum velocity is smaller, and overall effect is worse than double air bags.

Control Strategy and Expert System for Jig Operation

On the basis of the first jig separation stage, the relational mathematical model related to ash content and the coutent of coal gangue with a density less than 1. 8 g/cm3 is established. With this model, the discharge rate of reruse can be adjusted automatically and exactly by the conveutional PI regulator.The control stratedes for water capacity, air pressure, and feed capacity of the jig are introduced.Combined with the Expert system technology, jig expert system (JEP) is developed.

FLOWING FILM JIGGING FUNCTION IN THE NEW″IFFC″PROCESS FOR SEPARATING MINERALS OF ULTRAFINE SIZES

The concept of the flowing film jigging was first applied to the flowing film concentration area.The flowingfilm jigging function is an important element of the new process,in jection-flowing film centrifugation(IFFC),for separating and recovering minerals of ultrafine sizes.

THE RESEARCH OF THE MAGNETOHYDROSTATIC JIGGING SEPARATION

The Magnetohydrostatic Jigging Separation(MHSJS)is a method which makes use of the vibration of the solid particles obtained by applying a periodically changing magnetic Held to cause a periodically changing magnetic bouyancy to achieve an efficient separation of materials.