双肢“弓”形高强冷弯薄壁型钢拼合柱受压性能研究

采用有限元软件Abaqus对双肢“弓”形高强冷弯薄壁型钢拼合柱的受压性能进行了研究,分析了试件破坏模式以及长细比、自攻螺钉间距、腹板等效高厚比、偏心方向和偏心距对试件最大承载力的影响。结果表明:轴向受压试件和绕弱轴偏心受压试件,发生绕弱轴整体弯曲屈曲破坏;绕强轴偏心受压试件为局部屈曲或弯扭屈曲破坏;试件最大承载力和刚度随长细比、偏心距和腹板有效高厚比的增加而减小;当螺钉间距在100~300mm之间变化时,试件的最大承载力变化幅度在5.88%以内。依据《冷弯薄壁型钢结构技术规范》(GB50018-2002),计算得到最大承载力PG并与有限元值PA进行对比,结果表明:规范计算结果均较保守。对于轴压试件,PG与PA的差距随长细比的增大而减少。对于偏压试件,在相同长细比和偏心距的情况下,绕强轴偏压试件的PG与PA的差距比绕弱轴偏压试件更大。

软岩顶板薄煤层“弓”形采煤法

煤层顶板的岩性影响着煤炭的安全开采 ,软岩顶板薄煤层“弓”形采煤法的成功尝试 ,为该类顶板煤层的安全开采提供了范例 。

垭口型微地形输电线路区域风场仿真研究

目前国内对垭口型微地形的研究大多只针对山体之上的风速变化,而对山体周围的风场特性却鲜有研究。建立不同地形参数的垭口型微地形的三维计算模型,并利用FLUENT有限元软件对其风场特性进行仿真研究,得到山体之上及山体之后的风场分布规律。结果表明,风速只在垭口型微地形部分区域内有明显变化,风吹过垭口型微地形后呈现反"弓"形效应,即山谷正后方风速较来流风速有明显增大,而山体正后方的风速较来流风速不增反减。最后通过拟合得到微地形风场内的不同位置风速修正系数的计算公式,为输电线路的铁塔设计及安全性评价提供了理论参考。

两次对流天气的天气形势和多普勒雷达回波的对比分析

利用河北新乐多普勒雷达的探测资料和气象常规资料,通过对河北省中南部的两次灾害性天气(2005年7月12日和7月31日)对比分析,得出了对流天气(冰雹、大风)发生时有利的多普勒雷达产品的演变特征,"快速减少的垂直积分液态水可以引起风灾"、"逆风区"是造成灾害性天气的最明显和直接的表现。

软岩顶板薄煤层采煤法新尝试

煤层顶板的岩性影响着煤炭的安全开采 ,在软岩顶板条件下 ,薄煤层开采过程中 ,破碎顶板极易冒落 ,工作面无法正常推进 ,煤炭含矸量高 ,煤质不易保证。“弓”形采煤方法的成功尝试 ,解决了同类条件下煤层的安全开采问题 ,并且创造了很好的经济效益和社会效益。

FJZ-255／800防舞型双分裂间隔棒的研制

全国第一高塔、跨距最大的舟山与大陆联网大跨越工程主要分布在海面上。跨越塔最高的达到370m，跨越档距最大的达到2756m，这两项技术数据均为跨越工程之最。为满足跨越工程的要求，我们研制了一种新型“弓”形双分裂阻尼间隔棒，起到防止子导线之间鞭击、抑制微风振动、次档距振荡和舞动的作用。

Biological role of surface Toxoplasma gondii antigen in development of vaccine

AIM： To analyze the biological role of the surface antigen of Toxoplasma gondii（Tgondii） in development of vaccine. METHODS： The surface antigen of Tgondii （SAG1） was expressed in vitro. The immune response of the host to the antigen was investigated by detection of specific antibody reaction to SAG1 and production of cytokines. Mice were immunized with recombinant SAG1 and challenged with lethal strain of Tgondii RH. The monoclonal antibody to r-SAG1 was prepared and used to study the effects of SAG1 on Tgondii tachyzoites under electromicroscope. RESULTS： The mice immunized with recombinant SAG1 delayed death for 60 h compared to the control group. The recombinant SAG1 induced specific high titer of IgG and IgM antibodies as well as IFN-y, IL-2 and IL-4 cytokines in mice. In contrast, IL-12, IL-6 and TNF-α were undetectable. When T gondii tachyzoites were treated with the monoclonal antibody to r-SAG1, the parasites were gathered together, destroyed, deformed, swollen, and holes and gaps formed on the surface. CONCLUSION： SAG1 may be an excellent vaccine candidate against T gondii. The immune protection induced by SAG1 against Tgondii may be regulated by both hormone- and cell-mediated immune response.

Incidence of toxoplasmosis in patients with cirrhosis

AIM:It is known that toxoplasmosis rarely leads to various liver pathologies,most common of which is granulomatose hepatitis in patients having normal immune systems.Patients who have cirrhosis of the liver are subject to a variety of cellular as well as humoral immunity disorders.Therefore,it may be considered that toxoplasmosis can cause more frequent and more severe diseases in patients with cirrhosis and is capable of changing the course of the disease.The aim of this study was to investigate the frequency of toxoplasmosis in patients with cirrhosis. METHODS:Serum samples were taken from 108 patients with cirrhosis under observation in the Hepatology Polyclinic of the Gastroenterology Clinic,and a control group made up of 50 healthy blood donors.IFAT and ELISA methods were used to investigate the IgG and IgM antibodies,which had developed from these sera. RESULTS:Toxoplasma IgG and IgN antibody positivity was found in 74 (68.5%) of the 108 cirrhotic patients and 24 (48%) of the 50 people in the control group.The difference between them was significant (P<0.05). CONCLUSION:In conclusion,it was found that the toxopiasma sero-prevalence in the cirrhotic patients in this study was higher.Cirrhotic patients are likely to form a toxoplasma risk group.More detailed studies are needed on this subject.

Pancreaticoduodenectomy: Secondary stenting of the celiac trunk after inefficient median arcuate ligament release and reoperation as an alternative to simultaneous hepatic artery reconstruction

In patients undergoing pancreaticoduodenectomy(PD),unrecognized hemodynamically significant celiac axis(CA) stenosis impairs hepatic arterial flow by suppressing the collateral pathways supplying arterial flow from the superior mesenteric artery and leads to serious hepatobiliary complications due to liver and biliary ischemia, with a high rate of mortality. CA stenosis is usually due to an extrinsic compression by a previously asymptomatic median arcuate ligament(MAL). MAL is diagnosed by computerized tomography in about 10% of the candidates for PD, but only half are found to be hemodynamically significant during the gastroduodenal artery clamping test with Doppler assessment, which is mandatory before any resection. MAL release is usually efficient to restore an adequate liver blood inflow and prevent ischemic complications. In cases of failure in MAL release, postponed PD with secondary stenting of the CA and reoperation for PD should be considered as an alternative to immediate hepatic artery re-construction, which involves the risk of postoperative thrombosis of the arterial reconstruction. We recently used this two-stage strategy in a patient undergoing surgery for pancreatic adenocarcinoma.

CD2 deficiency partially prevents small bowel inflammation and improves parasite control in murine Toxoplasma gondii infection

To investigate whether bowel inflammation and/or parasite control is altered in the absence of the T cell adhesion molecule CD2.

A comparative analysis of 3D flow fields between straight and bowed blades in a steam turbine

A commercial Navier-Stokes flow solver has been employed for simulating steady subsonic flow characteristics and analyzing the comparative features of flow fields between straight and bowed blades applied to the stator of a high pressure steam turbine. For comparison, we have studied the effects of bowed blades on the wakes of stator trailing edge and horse shoe vortex in the rotor. It was found that the position of wakes for bowed blades is shifted toward the blade suction side. Also, we have discussed and compared the entropy generation and energy loss caused by dissipation mechanism within the boundary layers on the hub and shroud; and temperature gradient in meridional plane.

Dynamic Behavior of a New Hydraulic Steel Gate

A new style of hydraulic steel gate based on the principle of bionics is proposed in this paper. It has a fish-like shape and consists of right arches, invert arches, connection components and a face plate. It would be first applied in the project of Caoe River Sluice, used as both tidal barrage and flood gate. Compared with conventional hydraulic steel gate of beam grids, this new style of hydraulic steel gate can save up to 30%-50% of steel consumption. The dynamic behavior of the new gate under the impact load of tidal bore is investigated. The impact load of tidal bore is considered by a load spectrum obtained by field observation over a long period of time. Then a numerical analysis of the gate under the load spectrum is carried out by finite element method. The fluid-structure interaction is considered in the analysis. And a comparison between the response of the gate under the impact load and the response of the gate under the corresponding static load is conducted and indicates that the gate has a dynamic magnification factor of 1.2.

Pituitary prolactin adenoma with Toxoplasma gondii infection

Objective: To report two recent cases of pituitary adenoma associated with Toxoplasma gondii (T.Gondii) infection.Methods: Histological changes were observed in H & E and PAS staining sections microscopically.Immunohistochemistry was performed to classify the pituitary tumors and to confirm the diagnosis of T.gondii.Results: The cases were 43- and 19-year-old females, in which the latter one was a recurring case, and radiology examination showed that tumors existed in sellar region.Microscopically, the tumors consisted of small homogenous polygonal or round cells with abundant eosinophilic granular cytoplasm.Immunohistochemistry revealed they were prolactin-producing adenomas.Interestingly, we found toxoplasma infection in the tumor tissues, being confirmed by T.gondii sepicific antibody immunohistochemistry.Conclusion: The association of pituitary adenoma with toxoplasma raises the possibility that T.gondii may be involved in the development of certain cases of pituitary adenoma.

Area-wide Detection of Anti-Toxoplasma gondii Antibodies in Dairy Animals from the Khartoum State, Sudan

Toxoplasmosis is an important cause of reproductive failure in man and farm animals resulting in significant socio-economic losses worldwide. The aim of this study was to avail large scale data-regarding the sero-prevalence of T. gondii infection in dairy animals from the Khartoum State, Sudan using the commercially available Latex Agglutination Diagnostic kits. The study revealed that the overall seroprevalence of T. gondii infection at herd level of dairy animals in the State was 92.7%. The within herd seroprevalence was ranging from 8% up to 100% with mean of 51.3% in different herds of different dairy animals species in the State. Only 6 herds, 3 herds, 3 herds and 1 herd of cattle, camel sheep and goat respectively were found to be clean from anti-T, gondii antibody in the present study. Interestingly, most of the clean herds （12 herds） are located in the Khartoum district. The differences between the three districts, the seven localities and the four animal species were statistically highly significant （P 〈 0.01）. The overall sero-prevalence of T. gondii infection in dairy animals--at individual level--was 45.3%. Sheep scored the highest seroprevalence rate （75.0%） followed by goats （64.0%）, camels （54.1%） and cattle （40.9%） with high statistically significant differences （P 〈 0.01）. The highest level of antibody titration was reported in sheep and goats. This is the first area-wide and large scale report on seroprevalence of T. gondii infection in dairy animals from the Sudan. It was concluded that dairy animals in the Sudan are widely exposed to T. gondii and people in the Sudan should be aware of the possibility of hyper-prevalence of human toxoplasmosis through these food animals. Research on clinical toxoplasmosis in dairy animals and human in the Sudan is recommended to evaluate the role T. gondii infection in economical losses in dairy farm industry and for building strategy of sustainable toxoplasmosis control.

The First Report on Sero-Prevalence of Toxoplasma gondii in Working Horses and Donkeys in the Sudan

A serological survey of Toxoplasma gondii was conducted using LAT （Latex Agglutination Test） on 205 sera collected from working horses and donkeys in Khartoum State, Sudan. The overall sero-prevalence of the investigated equines was 32.7%. Antibodies to T. gondii were found in 38% of 100 horses and 27.6% of 105 donkeys. The titers were 1：2 （4 heads）, 1：4 （11 heads）, 1：8 （13 heads）, 1：16 （17 heads）, 1：32 （5 heads）, 1：64 （10 donkeys） and 1：128 （7 donkeys）. Neither the area nor animal species showed significant differences between the investigated groups. However, age was reported to show significant （P 〈 0.05） effect on equine toxoplasmosis in the Sudan. This is the first report on equine toxoplasmosis in the Sudan.

Low Sero-Prevalence of Toxoplasma gondii IgG and IgM Antibodies in HIV Sero-Positive Patients Attending National Hospital, Abuja, Nigeria

Several researchers have investigated the association of numerous opportunistic pathogens with HIV, little is documented on its association with T. gondii in our environment. We investigated the prevalence of T. gondii immunoglobulins G and M （IgG and IgM） in HIV positive individuals in relation to their cluster of differentiation 4 （CD4） cells count. IgG, IgM and CD4 were assayed using enzyme immunoassay （EIA） and flowcytometry respectively. 341 HIV positive individuals were studied in the present research, 30 （8.7%） of them had T. gondii IgG and IgM, 297 subjects had CD4 cells count a range of 200-400 cells/μL, 27 （9.7%） and 2 （0.6%） of which had T. gondii IgG and IgM respectively. Of the 44 HIV positive subjects with CD4 〉 400 cells/μL, one （2.2%） was positive for T. gondii IgG. In the control group, all the 177 had CD4 〉 400 cells/μL of which, one （0.5%） had T. gondii IgG. The prevalence of T. gondii infection was significantly higher in HIV positive individuals than in controls （P 〈 0.05）. Male subjects in the age bracket 18-30 years had significantly higher prevalence when compared to other groups （P 〈 0.05）. Although the present findings revealed a low prevalence of T. gondii antibodies in HIV infection, this suggests that a differential toxoplasmosis diagnosis is also necessary in cases of encephalitis in HIV infection.

Re-discussion on the Jiaochang Arcuate Structure, Sichuan Province, and the Seismogenic Structure for Diexi Earthquake in 1933

The Jiaochang arcuate structure is one of the numerous arcuate structural belts in Sichuan. The present paper gives a further argument about the characteristics of that arcuate structure and the new activity of the Songpinggou fault and affirms that the Songpinggou fault is an active fault in the Holocene epoch. The Diexi M 7.5 earthquake took place in 1933 on the west wing of that arcuate structure, near the apex of the arc. Many authors have given quite different opinions about the genetic structure of that earthquake. The authors have made on the spot investigations time and again over recent years. Besides this, the authors have also further studied the shape of intensity contour lines, the distribution characteristics of ground surface seismic hazards, the left lateral dislocation of buildings along the Songpinggou fault, the NW trending ground fissures that developed on the ground surface after earthquake, and so on. On this basis, it is still considered that the seismogenic fault of the 1933 Diexi M 7.5 earthquake was the Songpinggou fault on the west wing of the Jiaochang arcuate structure.

The Relationship Between Strong Earthquake Activity of M_S≥7.0 on the Chinese Mainland and the West Kunlun-A'nyêmaqên Secondary Arcuate Tectonic Zone

The active and quiet phenomenon of moderate strong earthquakes one year before the earthquakes with M S≥7.0, the spatial distribution characteristics of the solid tide modulating and triggering earthquakes and the strong earthquake mechanisms on the Chinese continent have been studied. The secondary arcuate tectonic zone composed of the west Kunlun-Anyêmaqên faults is believed to be a very important boundary to characterize strong earthquake activity of M S≥7.0 on the Chinese continent, that is, a boundary between the seismically active region and the quiet region of moderately strong earthquakes one year before earthquakes with M S≥7.0, and a boundary of the spatial distributions between the solid tide modulating strong earthquakes (M S≥7.0) and the non-modulating ones. It might be related with the characteristics of spatial distribution of focal mechanism solutions of strong earthquakes on the Chinese Continent.

The design of a novel parallel haptic device

A novel haptic device which is characterized by large workspace, high rigidity, simple kinematics and easy construction is presented. This device is a parallel mechanism which is composed of a base plate, three sub-chains, and a mobile plate. Each sub-chain is attached to the base plate through a pin joint and to the top plate through a spherical joint. The sub-chain is derived from and kinematically equivalent to a pantograph linkage but is redesigned to solve the difficult problem of motor-fitting. The spherical joint is of the ball-in-socket type, but has much larger workspace than its regular counterpart. The kinematics is analyzed, and the inverse kinematics analysis is performed with a geometric approach. The complete workspace is readily obtained with the spherical coordinate system searching method. The optimal value of the cone angle of the spherical joint is shown to be 100°.