预转变马氏体对GCr15钢贝氏体转变动力学的影响

本文利用磁性法和膨胀法研究了GCr15钢M_s点以下贝氏体转变动力学以及不同温度预转变马氏体对240℃等温时贝氏体转变动力学的影响。试验结果表明,过冷奥氏体在M_s点以下等温过程中首先形成变温马氏体,继而转变为下贝氏体。随着等温温度的降低和预淬马氏体数量的增加,应力促发作用有助于贝氏体转变的加速,200℃左右其孕育期最短。但是,当温度继续下降、预淬马氏体超过一定数量之后,贝氏体转变却愈趋困难,此外,M_s点以下不同温度的预转变马氏体对随后240℃等温时贝氏体转变动力学影响的研究结果,也具有相同的特性。

贝氏体预转变研究

运用扫描俄歇微区探针检测贝氏体预转变过程奥氏体晶界附近碳原子的分布，发现碳原子在晶界富集，近晶界区贫碳。建立了考虑晶界的贝氏体预转变热力学模型。计算结果表明，晶界附近贫碳区的形成满足热力学条件。

Fe-Ni合金预贝氏体转变的研究

用扫描俄歇显微探针，Ｘ射线衍射及扫描透射电镜对Ｆｅ－Ｎｉ合金预贝氏体转变进行了研究。结果表明，在中温等温时，奥氏体内出现了成分偏聚，形成了贫Ｎｉ区和富Ｎｉ区，贝氏体在贫Ｎｉ区形成。

以身许钢——记材料科学专家准贝氏体钢发明人康沫狂教授

在西工大静谧的校园里,人们常常会看到一位耄耋老者踯躇的身影,时而在实验室里埋首耕作;时而在校园小路上垂首凝思,以年愈八旬的高龄依然活跃在自己所钟情的事业上,这便是著名的准贝氏体钢发明人,西北工业大学康沫狂教授,一位终身心系我国钢铁事业的老科学家。 半个世纪前,我国钢铁工业比较落后。

Implication of the Hedgehog pathway in hepatocellular carcinoma

The prognosis for patients who are diagnosed with advanced stage hepatocellular carcinoma(HCC)is poor because there are few treatment options.Recent research has focused on the identification of novel molecular entities that can be targeted to inhibit oncogenic signals that are involved in the carcinogenesis,proliferation and progression of HCC.Among all of the pathways that are involved in the development of HCC,Hedgehog(HH)signalling has demonstrated a substantial role in hepatocarcinogenesis and HCC progression.HH plays a physiological role in embryogenesis,through the induction of the differentiation of hepatocytes from endodermal progenitors.The re-activation of the HH pathway in chronic damaged liver is a mechanism of fibrotic degeneration and is implicated in various stages of HCC development.HH activation sustains the subpopulation of immature liver epithelial cells that are involved in the pathogenesis of cirrhosis and HCC,and HH itself is a mediator of the alcohol-derived malignant transformation of liver cells.High levels of expression of HH protein markers in liver tumour tissues are correlated with aggressive histological and biological features and a poor clinical outcome.In vitro and in vivo inhibition models of the HH pathway confirm that HH is essential in maintaining tumour growth,metastasis and a mesenchymal phenotype.

Cullin 4A is associated with epithelial to mesenchymal transition and poor prognosis in perihilar cholangiocarcinoma

AIM To explore the functional role of cullin 4A(CUL4A), a core subunit of E3 ubiquitin ligase, in perihilar cholangiocarcinoma(PHCC).METHODS The expression of CUL4 A in PHCC cell lines was evaluated by Western blot and quantitative reverse transcription-polymerase chain reaction. Immunohistochemistry(IHC) was adopted to investigate the relationship between CUL4 A expression and clinicopathological characteristics of PHCC. Univariate analysis and multivariate regression analysis were performed to analyze the risk factors related to overall survival(OS) and progression-free survival(PFS) of PHCC patients. Wound healing, Transwell and Matrigel assays were utilized to explore the function of CUL4 A in PHCC metastasis. Furthermore, expression of epithelial to mesenchymal transition(EMT) markers was verified in cells with CUL4 A knockdown or overexpression. The relationship between CUL4 A expression and E-cadherin expression was also analyzed by IHC assay. Finally, the role of ZEB1 in regulating CUL4 A mediated PHCC was detected by IHC, Western blot, Transwell and Matrigel assays.RESULTS CUL4 A overexpression was detected in PHCC cell lines and clinical specimens. Clinicopathological analysis revealed a close correlation between CUL4 A overexpression and tumour differentiation, T, N and TNM stages in PHCC. Kaplan-Meier analysis revealed that high CUL4 A expression was correlated with poor OS and PFS of PHCC patients. Univariate analysis identified the following four parameters as risk factors related to OS rate of PHCC: T, N, TNM stages and high CUL4 A expression; as well as three related to PFS: N stage, TNM stage and high CUL4 A expression. Further multivariate logistic regression analysis identified high CUL4 A expression as the only independent prognostic factor for PHCC. Moreover, CUL4 A silencing in PHCC cell lines dramatically inhibited metastasis and the EMT. Conversely, CUL4 A overexpression promoted these processes. Mechanistically, ZEB1 was discovered to regulate the function of CUL4 A in promoting the EMT and metastasis.CONCLUSION CUL4 A is an independent prognostic factor for PHCC, and it can promote the EMT by regulating ZEB1 expression. CUL4 A may be a potential therapeutic target for PHCC.

Model predictive torque control of permanent magnet synchronous motor system driven by matrix converter

Employing matrix converter （MC） as driving mode, the strategy of model predictive torque control （MPTC） is proposed for three phase permanent magnet synchronous motor （PMSM） system. MC is applied instead of conventional AC DC AC converter to increase the power factor （PF） of the system input side. MPTC is used to select optimal voltage space vector to enable the system to have satisfactory torque and flux control effect. The resultant MPTC strategy not only makes the MC fed PMSM system operate reliably and have perfect control performance, but also makes the PF of the system input side be 1. Compared with direct torque control （DTC）, the proposed MPTC strategy guarantees that MC fed PMSM has better command following characteristics in the presence of variation of load torque and tracking reference speed. Simulation results verify the feasibility and effectiveness of the proposed strategy.

Doublecortin and CaM kinase-like-1 as an independent prognostic factor in patients with resected pancreatic carcinoma

To elucidate the effect of expression of doublecortin and CaM kinase-like-1 (DCLK1) in patients with pancreatic ductal adenocarcinoma (PDAC). METHODSTumor specimens were obtained from 136 patients with pancreatic cancer who had undergone resection without preoperative therapy between January 2000 and December 2013 at the Department of Surgical Oncology, Osaka City University. The resected specimens were analyzed for associations with clinicopathological data, including DCLK1 expression, epithelial mesenchymal transition (EMT) marker expression, and cancer stem cell (CSC) marker expression. Univariate and multivariate survival analyses were performed and we assessed the association between DCLK1 expression and clinicopathological factors, including the EMT marker and CSC marker. RESULTSIn total, 48.5% (66/136) of the pancreatic cancer samples were positive for DCLK1. Patients with DCLK1-positive tumors had significantly shorter survival times than those with DCLK1-negative tumors (median, 18.7 mo vs 49.5 mo, respectively; P < 0.0001). Positive DCLK1 expression correlated with histological grade (P = 0.0290), preoperative CA19-9 level (P = 0.0060), epithelial cell adhesion molecule (EpCAM) expression (P = 0.0235), and the triple-positive expression of CD44/CD24/EpCAM (P = 0.0139). On univariate survival analysis, five factors were significantly associated with worse overall survival: histological grade of G2 to G4 (P = 0.0091), high preoperative serum SPan-1 level (P = 0.0034), R1/2 (P < 0.0001), positive expression of DCLK1 (P < 0.0001) or CD44 (P = 0.0245). On multivariate survival analysis, R1/2 [odds ratio (OR) = 2.019, 95% confidence interval (CI): 1.380-2.933; P = 0.0004] and positive DCLK1 expression (OR = 1.848, 95%CI: 1.2854-2.661; P = 0.0009) were independent prognostic factors. CONCLUSIONDCLK1 expression was found to be an independent prognostic factor and it may play a crucial prognostic role by promoting acquisition of stemness.

The Basilica of Santa Maria di Collemaggio in L＇Aquila： Modern Provisional Measures

The case in analysis is Santa Maria di Collemaggio, the church symbol of the town of L＇Aquila and the most important example of Romanesque style in Abruzzi, tragically damaged by the earthquake in 2009. The following paper starts with an accurate analysis of the Basilica, whose historical, stylistical cultural characteristics make it an unicum in the whole urban environment. The authors tried to identify in which way these values have been compromised or altered after the earthquake through several analysis （surveys, historical researches etc.） aiming at the recognition of collapses, the cracks profile, the structural transformations caused by the provisional measures： the goal is to provide a kind of Basilica ＂cognitive manual＂ that will be useful for the future interventions. This first analysis allowed to understand many aspects： on the one hand, the constructive phases and which damages were caused by past careless interventions of restoration, drawing attention to the vulnerability elements of the Basilica; on the other hand, the innovative technologies and materials of the post-seismic provisional measures and their exact location.

Physical implication of two problems in transition prediction of boundary layers based on linear stability theory

Up to now,the most widely used method for transition prediction is the one based on linear stability theory.When it is applied to three-dimensional boundary layers,one has to choose the direction,or path,along which the growth rate of the disturbance is to be integrated.The direction given by using saddle point method in the theory of complex variable function is seen as mathematically most reasonable.However,unlike the saddle point method applied to water waves,here its physical meaning is not so obvious,as the frequency and wave number may be complex.And on some occasions,in advancing the integration of the growth rate of the disturbance,up to a certain location,one may not be able to continue the integration,because the condition for specifying the direction set by the saddle point method can no longer be satisfied on the basis of continuously varying wave number.In this paper,these two problems are discussed,and suggestions for how to do transition prediction under the latter condition are provided.

Free vibration analysis of a pre-twisted sandwich blade with thermal barrier coatings layers

A rotating cantilever sandwich-plate model with a pre-twisted and pre-set angle has been developed to investigate the vibrational behavior of an aero-engine turbine blade with thermal barrier coating(TBC) layers. The classic von Karman plate theory and the first-order shear deformation theory are applied to derive the energy equations of the rotating TBC blade, in which the geometric shapes, the work ambient temperature, and the TBC material properties are considered. The Chebyshev-Ritz method is used to obtain the nature frequency of the rotating TBC blade. For static frequency and modal analysis, the finite-element method(FEM)is also applied to compare and validate the results from the Chebyshev-Ritz method. A good agreement is found among these kinds of methods. For dynamic frequency, the results are analyzed in detail concerning the influence of system parameters such as the thickness of the TBC layer, the working temperature, and the pre-twisted and pre-set angle. Finally, the Campbell diagram is demonstrated to analyze the resonance property of the cantilever sandwich TBC blade model.