混流风机整机数值模拟及流固耦合分析（英文）

为了改进叶型设计方法、提升SWF型号风机的通风效率,运用数值模拟的方法,并结合fluent软件分析了该混流式风机整机的内部流场状态,获得了风机内部压力场和速度场等有价值的信息,再运用流固耦合的原理,借助Ansys workbench平台将所得到的风机流场内部的表压添加到风机固体模型上,得出了风机运行时的应力和位移结果。最后通过改变流速,得到了多组不一样的全压和效率值,利用Matlab软件可以拟合出风机的效率曲线。结果表明:应力从叶根位置到叶顶位置逐渐减小,叶根位置的应力值为最大值;位移从叶根位置到叶顶位置逐渐变大,最大的位移值出现在叶顶位置。同时得出了风机的运行工况在流速为6-8时的效率最高。

Soluble mannose receptor as a predictor of prognosis of hepatitis B virus-related acute-on-chronic liver failure

BACKGROUND Hepatitis B virus-related acute-on-chronic liver failure(HBV-ACLF)is a syndrome with a high short-term mortality rate,and it is crucial to identify those patients at a high mortality risk clinically.AIM To investigate the clinical value of soluble mannose receptor(sMR)in predicting the 90-day mortality of HBV-ACLF patients.METHODS A total of 43 patients were diagnosed with HBV-ACLF between October 2017 and October 2018 at the Second Hospital of Anhui Medical University,and all of them were enrolled in this retrospective study.Their serum sMR levels were determined using an enzyme-linked immunosorbent assay.Demographic and clinical data,including gender,age,albumin level,total bilirubin(TBIL)level,international normalized ratio,HBV-DNA level,HBV serological markers,procalcitonin level,interleukin-6 level,and model for end-stage liver disease(MELD)score were accessed at the time of diagnosis of HBV-ACLF.A multivariate logistic regression analysis was used to analyze the independent risk factors for mortality.RESULTS Serum sMR level was significantly increased in HBV-ACLF patients compared with chronic hepatitis B patients and healthy controls(P<0.01).When compared with surviving patients,it was higher in those patients who succumbed to HBVACLF(P<0.05).Serum sMR level was positively correlated with MELD score(rs=0.533,P=0.001),HBV-DNA level(rs=0.497,P=0.022),and TBIL level(rs=0.894,P<0.001).Serum sMR level(odds ratio=1.007,95%confidence interval:1.004–1.012,P=0.001)was an independent risk factor for the 90-day mortality in the HBV-ACLF cases.The patients with HBV-ACLF were stratified into two groups in accordance with their serum sMR levels at the baseline(low risk:<99.84 pg/mL and high risk:≥99.84 pg/mL).The 90-day mortality rates were 27.3%in the low-risk group and 87.5%in the high-risk group.Furthermore,sMR level apparently improved the performance of MELD score for predicting the prognosis of patients with HBV-ACLF.CONCLUSION Serum sMR level may be a predictor of the prognosis of HBV-ACLF patients.

Phase-field simulation of tip splitting in dendritic growth of Fe-C alloy

Two types of dendrite tip splitting including dendrite orientation transition and twinned-like dendrites in Fe-C alloys were investigated by phase-field method. In equiaxed growth, the possible dendrite growth directions and the effect of supersaturation on tip splitting were discussed; the dendrite orientation transition was observed, and it was found that the orientation regions of anisotropy parameters were reduced from three to two with increasing the supersaturation, which was due to the effect of interracial anisotropy controlled by the solute in front of S/L interface changing with the increase of supersaturation. In directional solidification, it was found that the twinned like dendrites were formed with the fixed anisotropy couples and no seaweed dendrites were observed; these were concluded from the results of competition between process anisotropy and inherent anisotropy. The formation process of twinned-like dendrite was investigated by tip splitting phenomenon, which was related to the chan ges of dendrite tips growth velocity. Then, the critical speed of tips splitting and solute concentration of twinned-like dendrites were investigated, and a new type of microsegregation in Fe-C alloys was proposed to supplement the dendrite growth theories.

Phase Transition Temperature Controllable Poly(acrylamide-co-acrylic acid) Nanocomposite Physical Hydrogels with High Strength

Poly（acrylamide-co-acrylic acid） nanocomposite physical （P（AAm-co-AAc）NCP） hydrogels have been prepared through the in situ free radical solution polymerization based on a ＂single network, dual cross-linkings＂ strategy. The P（AAm-co-AAc） NCP hydrogels are composed of nanobrushes of P（AAm-co-AAc） chains grafted on the surface of vinyl- hybrid silica nanoparticles （VSNPs）. In the hydrogel system, the VSNPs act as the ＂analogous chemical cross-linking points＂ once the hydrogen bonds formed between the P（AAm-co-AAc） chains of the nanobrushes, thus leading to the fabrication of high-strength P（AAm-co-AAc） NCP hydrogels. Compared with conventional thermosensitive P（AAm-co-AAc） hydrogels, the P（AAm-co-AAc） NCP hydrogels have a broader range of phase transition temperature, which can be adjusted by altering the monomer ratio, the VSNPs concentration, the addition of urea and N,N-dimethylacrylamide （DMAAm）. At the same time, the mechanical properties of the P（AAm-co-AAc） NCP hydrogels have been improved significantly by the introduction of VSNPs. Furthermore, both the phase transition and the tensile strength of the P（AAm-co-AAc） NCP hydrogels are largely influenced when Fe3＋ ions are introduced as the ionic crosslinkers into the hydrogel networks.