A Class of the Singularly Perturbed Boundary Value Problems for Elliptic Equation with a Super Surface of Turning Point in n-dimensional Space

In this paper, we study a class singular perturbed elliptic equation boundary value problem with a super surface of turning point in n-dimensional space by using the method of multiple scales and the comparison theorem. The uniformly valid asymptotic approxmations of solutions for the boundary value problem is constructed.

诗歌艺术散论

诗歌是文学中的文学,因而最讲究艺术性。诗歌在结构上讲究曲转,讲究披花拂柳,蜿蜒迭宕;诗歌可以用典,但"用典如水中着盐,但知盐味,不见盐质"。诗有无理之理,苏轼总结出一条重要的诗美学原则叫"反常合道"。反常,即违反常情,常理,常识,但合乎诗情,诗理,诗道。

Incompressible Pairwise Incompressible Surfaces in Knot Exteriors

We discuss the properties of incompressible pairwise incompressible surfaces in a knot complement by using twist crossing number. Let K be a pretzel knot or rational knot that its twistindex is less than 6, and let F be an incompressible pairwise incompressible surface in S 3-K. Then F is a punctured sphere.

STUDY OF NON-CONTACT MEASUREMENT OF FREE-FORM SURFACES

A non contact three dimensional measurement method is presented in this paper.This system consists of a laser triangulation probe,a probe head and a coordinate measuring machine (CMM).The measurement principle of the system is discussed,and a system calibration method employing a reference ball is proposed.The geometric model involving four frames is established to calculate the data points based on the reading of the laser probe and position information from the CMM.A measuring experiment for gesso free form surface using this system is carried out.

Drag Torque Prediction Model for the Wet Clutches

Reduction of drag torque in disengaged wet clutch is one of important potentials for vehicle transmission improvement. The flow of the oil film in clutch clearance is investigated. A three-dimension Navier-Stokes(N-S) equation based on laminar flow is presented to model the drag torque. Pressure and speed distribution in radial and circumferential directions are deduced. The theoretical analysis reveals that oil flow acceleration in radial direction caused by centrifugal force is the key reason for the shrinking of oil film as constant feeding flow rate. The peak drag torque occurs at the beginning of oil film shrinking. A variable is introduced to describe effective oil film area and drag torque after oil film shrinking is well evaluated with the variable. Under the working condition, tests were made to obtain drag torque curves at different clutch speed and oil viscosity. The tests confirm that simulation results agree with test data. The model performs well in the prediction of drag torque and lays a theoretical foundation to reduce it.

Lactobacillus crispatus M206119 exacerbates murine DSS-colitis by interfering with inflammatory responses

AIM： TO investigate the role of Lactobacillus crispatus （L. crispatus） strain China Center for Type Culture Col- lection （CCTCC） M206119 in intestinal inflammation.METHODS： Forty 8-wk-old Balb/c mice （20± 2 g） were divided into four groups of 10 mice each. Three groups that had received dextran sulfate sodium （DSS） were administered normal saline, sulfasalazine or CCTCC M206119 strain, and the fourth group received none of these. We assessed the severity of colitis using a disease activity index, measured the colon length and weight, collected stools and mesenteric lymph nodes for bacterial microflora analysis. One centimeter of the proximal colon, middle colon and distal colon were collected and fixed in 10% buffered formalin, dehydrated in ethanol, and embedded in paraffin. Interleukin （IL）- 1β, IL-6 and tumor necrosis factor （TNF）-α expression was detected using reverse transcription polymerase chain reaction. Protective factors zonula occludens （ZO）-1 and β-defensin 2 were detected by immunoblot-ting. The features of CCTCC M206119 strain were identified based on morphology, biochemical profile, and 16S RNA sequencing.RESULTS： DSS-colitis animals treated with CCTCC M206119 had markedly more severe disease, with greater weight loss, diarrhea, fecal bleeding, and shortened colon length. In addition, the CCTCC-M206119- treated group had comparatively higher histologi- cal scores and more neutrophil infiltration than the controls. Expression of protective factors ZO-1 and β-defensin 2 was downregulated due to destruction of the mucosal barrier after CCTCC M206119 strain treatment. An in vitro assay demonstrated that CCTCC M206119 strain increased the nuclear translocation of nuclear factor-κB in epithelial cells. Intestinal proinflam- matory or anti-inflammatory cytokine responses were evaluated. Proinflammatory colonic cytokine （IL-Iβ, IL-6 and TNF-α） levels were clearly increased in CCTCC- M206119-treated animals, whereas anti-inflammatory colonic cytokine （IL-10） level was lowered compared with saline or 5-aminosalicylic-acid-treated DSS-colitis mice. Next, CCTCC M206119 strain was characterized as 1. crispatus by microscopic morphology, biochemical tests and 16S rRNA gene level.CONCLUSION： Not all lactobacilli are beneficial for in- testinal inflammation, and L. crispatus CCTCC M206119 strain is involved in exacerbation of intestinal inflamma- tion in DSS-colitis mice.

Higher mode effects in hinged wall with BRBsin base-frame structures using distributed parameter models

To investigate the effect of higher modes on the displacement and inner forces in HWBB(hinged wall with buckling-restrained braces in base)-frame structure,distributed parameter models for both the HWBB-hinged frame structure and the HWBB-MRF(moment resisting frame)structure are built.The hinged wall is simplified as a flexural beam.BRBs(bucking-restrained braces)are simplified to a rotational spring.MRF is simplified to a shear beam.Vibration equations of distributed parameter models are derived.Natural periods,natural modes of vibration,inner forces and displacements of the distributed parameter models are derived based on the vibration equations using numerical methods.The effect of the relative stiffness ratio and the rotational stiffness ratio on the higher mode effects is investigated.For elastic structures,the global displacement and shear in MRF are predominantly controlled by the first mode,while the shear and bending moment in the wall are significantly affected by higher mode effects.The effect of the yielding of BRB on the inner forces distribution in the HWBB-hinged frame is investigated.The results indicate that the first mode will no longer contribute to the inner forces and the contribution from higher modes to inner forces increases after the BRBs yield.Displacement is not sensitive to higher mode effects and it is controlled by the first mode after the BRBs yield.Parameter analysis demonstrates that the displacement amplitudes are reduced with the increase in the flexural stiffness of the wall before the flexural stiffness reaches a certain value.The first three periods decrease with the increase in the rotational stiffness.With the increase in the rotational stiffness ratio,the contribution from the first mode decreases while contributions from both the second mode and third mode increase.

Preset model of bending force for 6-high reversing cold rolling mill based on genetic algorithm

The hydraulic roll-bending device was studied, which was widely used in modem cold rolling mills to regulate the strip flatness. The loaded roll gap crown mathematic model and the strip crown mathematic model of the reversing cold rolling process were established, and the deformation model of roll stack system of the 6-high 1 250 mm high crown （HC） reversing cold rolling mill was built by slit beam method. The simulation results show that, the quadratic component of strip crown decreases nearly linearly with the increase of the work roll bending force, when the shifting value of intermediate roll is determined by the rolling process. From the first pass to the fifth pass of reversing rolling process, the crown controllability of bending force is gradually weakened. Base on analyzing the relationship among the main factors associated with roll-bending force in reversing multi-pass rolling, such as strip width and rolling force, a preset mathematic model of bending force is developed by genetic algorithm. The simulation data demonstrate that the relative deviation of flatness criterions in each rolling pass is improved significantly and the mean relative deviation of all five passes is decreased from 25.1% to 1.7%. The model can keep good shape in multi-pass reversing cold rolling process with the high prediction accuracy and can be used to guide the production process.

Epigenetic inactivation of secreted frizzled-related protein 2 in esophageal squamous cell carcinoma

AIM： To investigate the expression and methylation status of the secreted frizzled-related protein 2 （SFRP2） in esophageal squamous cell carcinoma （ESCC） and ex- plore its role in ESCC carcinogenesis.METHODS： Seven ESCC cell lines （KYSE 30, KYSE150, KYSE410, KYSE510, EC109, EC9706 and TE-1） and one immortalized human esophageal epithelial cell line （Het- 1A）, 20 ESCC tissue samples and 20 paired adjacent non-tumor esophageal epithelial tissues were analyzed in this study. Reverse-transcription polymerase chain reaction （RT-PCR） was employed to investigate the expression of SFRP2 in cell lines, primary ESCC tumor tissue, and paired adjacent normal tissue. Methylation status was evaluated by methylation-specific PCR and bisulfite sequencing. The correlation between expres- sion and promoter methylation of the SFRP2 gene was confirmed with treatment of 5-aza-2＇-deoxycytidine. To assess the potential role of SFRP2 in ESCC, we es-tablished stable SFRP2-transfected cells and examined them with regard to cell proliferation, colony formation, apoptosis and cell cycle in vivo and in vitro.RESULTS： SFRP2 mRNA was expressed in the im- mortalized normal esophageal epithelial cell line but not in seven ESCC cell lines. By methylation-specific PCR, complete methylation was detected in three cell lines with silenced SFRP2 expression, and extensive methylation was observed in the other four ESCC cell lines. 5-aza-2＇-deoxycytidine could restore the expres- sion of SFRP2 mRNA in the three ESCC cell lines lack- ing SFRP2 expression. SFRP2 mRNA expression was obviously lower in primary ESCC tissue than in adjacent normal tissue （0.939 ± 0.398 vs 1.51 ± 0.399, P 〈 0.01）. SFRP2 methylation was higher in tumor tissue than in paired normal tissue （95% vs 65%, P 〈 0.05）. The DNA methylation status of the SFRP2 correlated inversely with the SFRP2 expression. To assess the potential role of SFRP2 in ESCC, we established stable SFRP2 transfectants and control counterparts by in- troducing pcDNA3.1/v5 hisA -SFRP2 or pcDNA3.1/v5 hisA -empty vector into KYSE30 cells lacking SFRP2 expression. After transfection, the forced-expression of SFRP2 was confirmed by the RT-PCR. In comparison with the control groups, stably-expressed SFRP2 in KYSE 30 cells significantly reduced colony formation in vitro （47.17% 4± 15.61% vs 17% ：1： 3.6%, P = 0.031） and tumor growth in nude mice （917.86：1：249.35 mm3 vs 337.23 ± 124.43 mm3, P 〈 0.05）. Using flow cytom- etry analysis, we found a significantly higher number of early apoptotic cells in SFRP2-transfected cells than in the control cells （P = 0.025）. The mean cell number in the S and G2-M phases of the cell cycle was also significantly lower in SFRP2-transfected KYSE30 cells compared with mock transfected counterparts. CONCLUSION： Silencing of SFRP2 expression through promoter hypermethylation may be a factor in ESCC carcinogenesis through loss of its tumor-suppressive activity.

On Quadratric Rotational Curved Surface

In this paper,a deterministic theorem is proposed for quadratic rotational curved surface.The relationship between invariants for quadratic rotational curved surface is established.In addition we give each type of equitions for rotational curved surface using the invariant.

Multi-object optimization design for differential and grading toothed roll crusher using a genetic algorithm

Our differential and grading toothed roll crusher blends the advantages of a toothed roll crusher and a jaw crusher and possesses characteristics of great crushing,high breaking efficiency,multi-sieving and has,for the moment,made up for the short- comings of the toothed roll crusher.The moving jaw of the crusher is a crank-rocker mechanism.For optimizing the dynamic per- formance and improving the cracking capability of the crusher,a mathematical model was established to optimize the transmission angleγand to minimize the travel characteristic value m of the moving jaw.Genetic algorithm is used to optimize the crusher crank-rocker mechanism for multi-object design and an optimum result is obtained.According to the implementation,it is shown that the performance of the crusher and the cracking capability of the moving jaw have been improved.

Analysis of the flexural vibration of ship's tail shaft by transfer matrix method

A ship's tail shaft has serious flexural vibration due to the cantilevered nature of the propeller's blades.Analysis of the nature frequency of flexural vibration is vital to be able to provide effective shock absorption for a ship's tail shaft.A mathematic model of tail shaft flexural vibrations was built using the transfer matrix method.The nature frequency of flexural vibration for an electrically propelled ship's tail shaft was then analyzed,and an effective method for calculating it was proposed:a genetic algorithm(GA),which calculates the nature frequency of vibration of a system.Sample calculations,with comparisons by the Prohl method under conditions bearing isotropic support,showed this method to be practical.It should have significant impact on engineering design theory.

“Passive-bending colonoscope”significantly improves cecal intubation in difficult cases

Colonoscopy sometimes causes pain during insertion,especially in difficult cases.Over-insufflation of air causes elongation or acute angulations of the colon,making passage of the scope difficult and causing pain.We previously reported a sedative-risk-free colonoscopy insertion technique,namely,"Water Navigation Colonoscopy".Complete air suction after water infusion not only improves the vision,but also makes water flow down to the descending colon,while the sigmoid colon collapses and shortens.While non-sedative colonoscopy can be carried out without pain in most cases,some patients do complain of pain.Most of these patients have abnormal colon morphology,and the pain is caused while negotiating the "hairpin" bends of the colon.The "hairpin" bends of the colon should be negotiated by gently pushing the full-angled colonoscope.The proximal 10-20 cm from the angulated part of the conventional colonoscope is stiff,with a wide turning radius,therefore,a conventional colonoscope cannot be negotiated through the "hairpin" bends of the colon without stretching them and causing pain.The "passive-bending colonoscope" has a flexible tip with a narrow turning radius,so that the scope can be negotiated through the "hairpin" bends of the colon with a minimum turning radius and minimal discomfort.Therefore,the intubation and pain-reducing performance of the "passive-bending colonoscope" was assessed in difficult cases.

Factor Price Distortion and Conseq uential A dverse Wealth Transfers in China

As critical piece of China＇s gradualist economic transition, domestic price reform still faces major challenges. In particular, factor price, which is still tightlycontrolled and not market-based, is lower than market equilibrium price. Factor price distortion not only reduces market efficiency but also affects wealth distribution. Subsequent wealth transfer has, over the past ten to fifieen years, created a powerful vested interests and spawned social resentment, both of which may constitute major hazards in China＇s future reform and development. Keeping in mind that China will have to address factor price distortion in its next step of reform, this paper takes stock of China＇s journey toward price rejorm; examines the relationship among factor price distortion, previous economic growth, and policy; and estimates＇ the size of resulting wealth transfer.

Development and control of flexible pneumatic wall-climbing robot

A new kind of flexible pneumatic wall-climbing robot,named WALKMAN-I,was proposed. WALKMAN-I is basically composed of a flexible pneumatic actuator (FPA),a flexible pneumatic spherical joint and six suction cups. It has many characteristics of low-cost,lightweight,simple structure and good flexibility. Its operating principle was introduced. Then three basic locomotion modes,which are linear motion,curvilinear motion and crossing the orthogonal planes,were presented. The safety conditions of WALKMAN-I were discussed and built. Finally,the control system was designed and experiments were carried out. Experimental results show that WALKMAN-I is able to climb on the vertical wall surface along a straight line or a curved path,and has the ability of crossing orthogonal planes and obstacles. The maximum rotation angle reaches 90°,the maximum velocity reaches 5 mm/s,and the rotation angle and the moving velocity of WALKMAN-I can be easily controlled.

ROUTING ALGORITHM FOR THE ROTATION-EXCHANGE NETWORK

The paper proposes a new routing algorithm for the Rotation-Exchange (REn) network. The length of the path between any two nodes given by the algorithm is not more than (3/8)n2 + O(n), that is, the diameter of REn is not more than (3/8)n2 + O(n). This improves on a (1/2)n2 + O(n) routing algorithm proposed earlier.

Cyclic behavior test of a new double-arch steel gate

A new double-arch structure for the gate used as tidal barrage and sluice was adopted in Caoe River Dam in China. It was a spatial structure made up of the right arch, the invert arch, the chord, etc., and was designed to bear bilateral loads. To research the cyclic behavior of the new double-arch structure, a scale-model cyclic test was conducted. First, the test setup and test method were presented in detail, and according to the test results, the cyclic behavior and failure characteristics of this structure were discussed. Then by analyzing the test cyclic envelope curve, it was found the curve was divided into three stages: the elastic stage, the local plastic stage and the failure stage at the local yield point and structural yield point. The gate model has local yield strength and structural yield strength, with both their values being bigger than that of the designing load. Therefore, the gate is safe enough for the projects. At last, dynamic property of the gate was analyzed considering additional mass of the water. It was found that the tidal bore shock would not cause resonance vibration of the gate.

A new network losses allocation method in deregulated environment

Network losses allocation is one of the major problems in the market environment. The quadric function of the injected nodal power is used in this paper as a representation for network losses, which are allocated fairly using the called market equilibrium principle while the bidding curves are corrected. The power market equilibrium is simulated as three different models that can be solved simply by the optimal power flow algorithm combining the generation scheduling problem with network losses allocation. The case study is made at an IEEE-30 nodes system and a perfect result is proved in this paper.

Distortional buckling analysis of steel-concrete composite box beams considering effect of stud rotational restraint under hogging moment

Restrained distortional buckling is an important buckling mode of steel-concrete composite box beams(SCCBB)under the hogging moment.Rotational and lateral deformation restraints of the bottom plate by the webs are essential factors affecting SCCBB distortional buckling.Based on the stationary potential energy principle,the analytical expressions for the rotational restraint stiffness(RRS)of the web upper edge as well as the RRS and the lateral restraint stiffness(LRS)of the bottom plate were derived.Also,the SCCBB critical moment formula under the hogging moment was derived.Using twenty specimens,the theoretical calculation method is compared with the finite-element method.Results indicate that the theoretical calculation method can effectively and accurately reflect the restraint effect of the studs,top steel flange,and other factors on the bottom plate.Both the RRS and the LRS have a nonlinear coupling relationship with the external loads and the RRS of the web’s upper edge.Under the hogging moment,the RRS of the web upper edge has a certain influence on the SCCBB distortional buckling critical moment.With increasing RRS of the web upper edge,the SCCBB critical moment increases at first and then tends to be stable.

New extrusion process of Mg alloy automobile wheels

The recent research and development of forged magnesium road wheel were reviewed.Methods of flow-forming,spin forging of manufacturing a forged magnesium alloy wheel were introduced.A new extrusion method was investigated especially. Extrusion from hollow billet was proposed in order to enhance the strength of spoke portion and reduce the maximum forming load. By means of the developed technique,the one-piece Mg wheels were produced successfully by extrusion from AZ80+alloy.At the same time,the existing problems on the research and development of forged magnesium road wheel were analyzed.The impact testing,radial fatigue testing and bending fatigue testing results show that AZ80+wheel can meet application requirement in automobile industry.