螺板轧机锥辊理论辊缝

通过轧机调整参数的研究，提出实用的共轭理论辊缝解析法，结合考虑其它影响参数的修正，可对螺旋叶片轧制参数调整起到重要指导意义．

螺板异面锥辊轧制工艺研究

通过理论分析与生产实践的结合，详尽地讨论螺板轧制工艺参数定量定性的调整方法，将有助于有效控制螺板变形，提高轧机调整效率．

唾液测试板检测口腔幽门螺杆菌的实用性研究

目的探讨幽门螺杆菌唾液测试板(HPS)与碳-13尿素呼气试验(13C-UBT)检测口腔幽门螺杆菌的相关性及其诊断的特异性及灵敏性。方法选择13C-UBT检测阳性者106例和13C-UBT检测阴性者24例,共130例研究对象,采用HPS法进行口腔幽门螺杆菌检测。以13C-UBT为金标准,对HPS法检测结果用贝叶斯定理方法进行评价。结果HPS的灵敏度为68.87%,特异度为58.33%,准确度为66.92%,阳性预测值为87.95%,阴性预测值为29.79%。二者的符合率为66.92%。结论HPS法与13C-UBT法的检测结果具有一定的相关性,13C-UBT法对口腔幽门螺杆菌检测存在盲区,不适用于作为评价口腔幽门螺杆菌检测方法HPS的金标准。HPS法与13C-UBT法可临床上同步使用。

板式螺旋桨搅拌槽内的流场及其流动特性

以板式螺旋桨叶轮为例,采用相位多普勒粒子分析仪测量了直径为300 mm的平底圆筒搅拌槽内的流场;分析了时均速度、脉动速度及湍流动能的分布,以及叶轮离底间隙变化和挡板对流场的影响。结果表明:随离底间隙增大,叶轮区脉动速度和湍流动能增大,时均速度和脉动速度最大值位置向槽中心方向移动;主循环区轴向速度最大值随离底间隙增大而减小;叶轮区湍流动能较高,随离底间隙增大,湍流动能最大值增大,位置靠近叶轮端部;挡板阻碍槽内切向流动,影响湍流动能的分布,挡板前流场反映了叶轮区的湍流动能分布。

锁定加压螺孔型接骨板治疗四肢骨折40例体会

目的：探讨锁定加压螺孔型接骨板治疗四肢骨折的应用及疗效。方法：采用锁定加压螺孔型接骨板治疗四肢骨折40例，并对治疗结果加以观察。结果：40例随访6～48个月，骨折均获得骨性愈合，无并发症发生。结论：锁定加压螺孔型接骨板是治疗四肢骨折的理想内固定方式，骨折愈合率高，值得临床推广使用。

口腔与胃内幽门螺杆菌感染的相关性

目的探讨口腔幽门螺杆菌（Hp）感染与胃Hp感染的相关性，及口腔Hp感染对Hp根除治疗的影响。方法选择216例上消化道不适患者，均给予幽门螺杆菌唾液测试板（HPS），13C-UBT检测，以13C—UBT为金标准，对HPS法检测结果用贝叶斯定理方法进行评价。选择13C-UBT阳性患者168例，经PPI三联或四联7天疗法规范的抗Hp治疗后4周和3个月，复查13C-UBT，并对两者结果进行对比研究。结果①利用贝叶斯定理计算得出：在口腔感染Hp发生的条件下胃感染Hp发生的概率为84．1％。HPS的灵敏度为66．1％，特异度为56．3％，阳性预测值为84．1％，阴性预测值为32．1％。②216例上消化道不适患者中，HPS阳性率为61．1％，13C-UBT阳性率为77．8％，两种检测方法比较，差异有统计学意义（x2=14．138，P〈0．01）．13C-UBT阳性者，HPS阳性率为66．1％；13C-UBT阴性者，HPS阳性率为43．8％，两者比较差异有统计学意义（x2=7．827，P〈0．01）。③治疗后4周，HPS阳性者（n=75），胃Hp根除率为93．3％；HPS阴性者（n=27），胃HP根除率为92．6％，两者比较差异无统计学意义（x2=0．000，P〉0．05）．3个月后，HPS阴性者（n=42）胃HP根除率（63．2％），明显高于HPS阳性者（n=19）（33．3％），两者比较差异有统计学意义（x2=4．758，P〈0．05））。结论口腔HP感染与胃内Hp感染密切相关，胃Hp的感染复发率受口腔Hp存在的影响。

慢性胃炎患者口腔幽门螺杆菌感染对胃幽门螺杆菌根除率的影响

目的探讨慢性胃炎患者口腔幽门螺杆菌(Hp)感染对胃Hp根除率的影响。方法选择14C尿素呼气试验(14C-UBT)阳性、符合Hp根除治疗指征的Hp相关性慢性胃炎患者200例,所有入选患者治疗前行唾液幽门螺杆菌抗原测试板(HPS)检测,予以标准质子泵抑制剂(PPI)三联7d疗法治疗。疗程结束后4周同时接受HPS与14C-UBT复查。根据治疗后HPS检测结果,分为HPS阳性组和HPS阴性组,比较胃Hp根除率。结果治疗前HPS检测阳性率为70.00%(140/200),治疗后为64.52%(120/186),两者比较差异无统计学意义(掊2=1.32,P>0.05)。186例中治疗后HPS阳性组胃Hp根除率为60.00%(72/120),HPS阴性组胃Hp根除率为87.88%(58/66),两组比较差异有统计学意义(掊2=15.73,P<0.005)。结论标准PPI三联7d疗法对口腔Hp感染的治疗几乎无效,有口腔Hp感染的慢性胃炎患者胃Hp根除率明显低于无口腔Hp感染者,口腔Hp感染与胃Hp感染的同步检测和治疗将是今后Hp研究的主攻方向。

C反应蛋白在胃黏膜、口腔幽门螺旋杆菌感染中的意义

目的探讨胃黏膜及口腔幽门螺旋杆菌(HP)感染与C反应蛋白(CRP)的相关性。方法选择196例HP阳性患者,检测其CRP,然后给予三联抗HP治疗,4周后复查HP、CRP,HP仍阳性患者行幽门螺旋杆菌唾液测试板法(HPS)检查,得到HP阳性及阴性、HSP阳性及阴性4组患者CRP值,将上述结果进行统计分析。结果 HP、HPS阳性患者的CRP水平相比对应阴性患者显著升高,差异有统计学意义(P<0.05)。结论 HP感染与血清CRP水平密切相关。

Analysis of secondary flow in shell-side channel of trisection helix heat exchangers

The flow characteristics of shell-side fluid in the tube-and-shell heat exchangers with trisection helical baffles with 35° inclined angles are numerically analyzed. The secondary flow distribution of the fluid in the shell-side channel is focused on. The results on meridian planes indicate that in the shell-side channel, the center part of fluid has an outward tendency because of the centrifugal force, and the peripheral region fluid has an inward tendency under the centripetal force. So in a spiral cycle, the fluid is divided into the upper and lower beams of streamlines, at the same time the Dean vortices are formed near the left baffle, and then the fluid turns to centripetal flow near the right baffle. Finally the two beams of streamlines merge in the main flow. The results of a number of parallel slices between two parallel baffles with the same sector in a swirl cycle also show the existence of the secondary flow and some backward flows at the V-gaps of the adjacent baffles. The secondary flows have a positive effect on mixing fluid by promoting the momentum and mass exchange between fluid particles near the tube wall and in the main stream, and thus they will enhance the heat transfer of the helix heat exchanger.

锁定钛板螺孔塞的设计与线性静力有限元分析

目的设计胫骨近端外侧锁定钛板螺孔塞，建立胫骨近端骨折固定有限元模型，通过线性静力有限元分析了解螺孔塞设计理念的可行性与价值。方法设计螺孔塞后，对正常胫骨进行CT扫描，通过数字骨科技术建立胫骨折、腓骨、髌韧带、近端外侧锁定钛板以及螺孔塞理想化数字模型，装配后建立“稳定腓骨使用螺孔塞”、“稳定腓骨不使用螺孔塞”、“不稳定腓骨使用螺孔塞”、“不稳定腓骨不使用螺孔塞”4种骨折内固定有限元分析模型，对4种模型分别施加相同的26组载荷，进行线性静力分析。记录并比较4种模型骨折面相对位移最大值、骨折面相对位移平均值、内固定最大VonMises应力、骨折面最大接触应力、钛板．骨界面最大接触应力、骨折面最大接触力、钛板一骨界面最大接触力。结果使用塞子与不使用塞子在骨折面相对位移最大值、骨折面相对位移平均值、内固定最大VonMises应力、钛板与骨面最大接触压力方面差异有统计学意义（P〈0．05），而在骨折面最大接触压力方面差异无统计学意义（P〉0．05）；不稳定腓骨使用螺孔塞情况下对内固定最大VonMises应力改善更为显著，差异有统计学意义（P〈0．05）。结论使用螺孔塞小幅增加钛板与骨面接触力，减少了内固定最大VonMises应力、模型整体最大位移、骨折面相对与平均位移，而对骨折面接触压力影响并不明显，能改善骨折内固定生物力学环境，具备深入研究价值。

Effects of Shape and Quantity of Helical Baffle on the Shell-side Heat Transfer and Flow Performance of Heat Exchangers

Shape and quantity of helical baffles have great impact on the shell-side performance of helical baffled heat exchangers （HBHE）. In this work, three physical models of HBHE with baffles of different shape （trisection, quadrant and sextant sector） were investigated. Numerical simulations were performed on HBHE at three helix an- gles （10°, 25° and 40°） by the software ANSYS CFX. Analyses of numerical results indicate that the sextant HBHE shows relatively better fluid flow performance because the leakage flow in the triangle area is evidently reduced and the fluid streamline appears much closer to an ideal spiral flow, while the trisection and quadrant HBHE show more scattered and disordered streamline distributions. The convective heat transfer coefficient and pressure drop in three types of HBHE were presented. Further investigations on the shell side performance with different helical baf- fles were implemented by the field synergy theory. Both theoretical and numerical analyses gave support on the re- lations between helical baffle shape and shell-side performance. This paper may provide useful reference for the selection of baffle shade and auantitv in HBHE.

Alternative flat coil design for electromagnetic forming using FEM

Electromagnetic forming （EMF） is a high velocity forming process that uses impulse magnetic force. Coil is an important component of EMF system which needs to be designed depending on application. Flat spiral coils are generally used for electromagnetic forming of sheet metals. However, with this type of coil the central portion of the workpiece experiences marginal magnetic force. This leads to in-sufficient deformation at this portion and other problems like air entrapment. In this study, a conceptual design of flat coil was proposed for better distribution of magnetic forces over the workpiece. Comparative analysis of distribution of magnetic force, magnetic field and current density using the proposed and the existing coil designs were carried out using FEM. The result indicates that the proposed coil design produces comparatively better magnetic force distribution over the workpiece. Calculation of self-inductance of such coils was also carried out and was compared with FE simulation.

Comparison of heat transfer performances of helix baffled heat exchangers with different baffle configurations

Numerical simulations were performed on flow and heat transfer performances of heat exchangers having six helical baffles of different baffle shapes and assembly configurations, i.e., two trisection baffle schemes, two quadrant baffle schemes, and two continuous helical baffle schemes. The temperature contour or the pressure contour and velocity contour plots with superimposed velocity vectors on meridian, transverse and unfolded concentric hexagonal slices are presented to obtain a full angular view. For the six helix baffled heat exchangers,the different patterns of the single vortex secondary flow and the shortcut leakage flow were depicted as well as the heat transfer properties were compared. The results show that the optimum scheme among the six configurations is a circumferential overlap trisection helix baffled heat exchanger with a baffle incline angle of 20°(20°TCO) scheme with an anti-shortcut baffle structure, which exhibits the second highest pressure dropΔpo, the highest overall heat transfer coefficient K, shell-side heat transfer coefficient hoand shell-side average comprehensive index ho/Δpo.

Test and application of hydraulic expansion bolts in a roadway under goaf with ultra-close separation

The roof of a roadway under goal with ultra-close separation consists of thin rock strata and rocks caving in upper goal. Influenced by the mining of the upper coal seam, the roof is loose and broken, and its integ- rity is poor. Resin anchored bolts cannot provide an effective anchoring force in such roof conditions. By conducting free expansion tests and field pull-out tests on a hydraulic expansion bolt, this study has ana- lyzed the influencing factors and laws of radial expansion and anchoring force changes in the rod body. This has revealed the anchoring mechanism of such bolts, and has obtained reasonable water injection pressures and suitable drilling diameters （which are 20-25 MPa and 32-35 mm respectively） for the hydraulic expansion bolt （cR28 mm） used in these tests. Based on pull-out tests at different interlayer spacing, the applicability of hydraulic expansion bolts had been verified for controlling the roof of road- ways under goal with ultra-close distance. Combined with the deformation and failure characteristics of the test roadway roof, this paper proposes a united roof-control technology based on the use of hydraulic expansion bolts and advancing intubation for the roof. Engineering practice indicated that the roof of the test roadway did not generate leaking and caving phenomenon, and the amount of roof deformation was controlled to within 150 mm. Maintenance of the roadway roof has been improved significantly, which ensures safe mining in coal seams with ultra-close separation.

Mechanical property of single-bolted composite laminates

In order to investigate the effects of different geometrical parameters and pretightening loads on failure mode and bearing strength,a large number of single-bolted T300/QY8911 composite laminates were tested under static tension load.Box-plot was used to extract the singular testing values of bearing strength and effective statistical values were obtained.T-test method of independent samples was used to study how much pretightening loads influence bearing strength.The results show that the geometrical parameters,such as ratios of width to hole diameter(w/d) and edge distance to hole diameter(e/d),remarkably influence failure mode and bearing strength.Net-section failure will occur when w/d is smaller than 4,and shear-out failure will occur when e/d is smaller than 2.Bearing failure or bearing and shear-out combined failure will occur when w/d is greater than 4 and e/d is greater than 2.There is an optimal combination of geometrical parameters to achieve the highest bearing strength.For most of specimens,pretightening loads do not explicitly influence bearing strength.

Design methods of headed studs for composite decks of through steel bridges in high-speed railway

Aimed at two typical composite floor systems of through steel bridges in high speed railway,design methods of headed studs were put forward for different composite members through comparing and analyzing the structure,mechanical characteristics and transmission routes of deck loads.The simplified calculation models were brought out for the stud design of the longitudinal girders and transverse girders in the composite floor system of Nanjing Dashengguan Yangtze River Bridge (NDB).Studs were designed and arranged by taking the middle panel of 336 m main span for example.The results show that under deck loads,the longitudinal girders in the composite floor system of through steel bridges are in tension-bending state,longitudinal shear force on the interface is caused by both longitudinal force of "The first mechanical system" and vertical bending of "The second mechanical system",and studs can be arranged with equal space in terms of the shear force in range of 0.2d (where d is the panel length) on the top ends.Transverse girders in steel longitudinal and transverse girders-concrete slab composite deck are in compound-bending state,and out-of-plane bending has to be taken into account in the stud design.In orthotropic integral steel deck-concrete slab composite deck,out-of-plane bending of transverse girders is very small so that it can be neglected,and studs on the orthotropic integral steel deck can be arranged according to the structural requirements.The above design methods and simplified calculation models have been applied in the stud design of NDB.

Depillaring of total thickness of a thick coal seam in single lift using cable bolts：A case study

Explaining fundamentals of application of cable bolting for a thick seam depillaring,this paper summarizes the results of field studies conducted during adoption of this approach in more than fifteen panels of Madhusudanpur 7 pit and incline mine.Nearly 7.0 m thick Kajora top coal seam of this mine is developed on pillars along the floor horizon to an average height of 3.0 m,leaving a coal band of around 4.0 m along the roof.Analysis of procured core samples showed that roof strata are easily caveable with a caveability index value of around 2000 only.Easily caveable overlying strata and shallow depth of cover alleviated most of the expected strata mechanics problems of the thick seam mining.However,extraction of total thickness at shallow cover caused differential-subsidence and cracks on the surface.These manifestations were immediately tackled to avoid creation of a breathing path for spontaneous heating in the extracted area.

Research into stope roof control of compound roof by solid backfilling mining

Based on the analysis of the failure characteristics and backfilling effect of the compound roof at 1801 backfilling workface in Taiyuan coal mine, China, we propose a method of controlling the pre- subsidence of a compound roof by using pre-stressed bolts to improve the backfilling ratio of the work- face so as to maintain the global stability of the stope roof. In addition, PHASE simulation software was employed to analyze the influence law of pre-stressing force, length, and interval on roof subsidence at the workface. On the basis of the numerical simulation results, a model for calculating the pre-stressing force and length of the bolts, the interval between the bolts, as well as roof subsidence at the workface, was established by using SPSS regression analysis software. Moreover, the research results were applied successfully to the 1801 filling workface. According to the monitoring data of roof closure, it was found that the final subsidence value for the goal roof was 350 mm and the filling ratio at the workface was 86%, which could fully meet the demand for safety production at the workface. The safe and effective control of the stope roof was therefore realized, which achieves the goal of safe and efficient backfilling mining under a compound roof.

Technical Study for Inflector and Central Region of High Intensity Central Region Model Cyclotron

The central region model (CRM) cyclotron is the experimental platform for the key technology study of a high intensity beam cyclotron.In this paper we introduce the spiral inflector and central region designed for the CRM cyclotron,including the physical design,the numerical control machining and the installation precision control techniques.The shape of electrodes is complex,and machining with a strict tolerance must be done by a numerical control machine tool with the number of its axles no less than 4.The electrodes of central region were finished by using 3-axle machine tools.The size of gaps between the ground and Dee tip is very important,a special device was made to guarantee the installation precision,and the error of gaps was controlled within±0.05mm.