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51.
In the numerical analysis of manufacturing processes of metal parts, many material properties depending on, for example, the temperature or stress state, must be taken into account. Often these data are dependent on the temperature changes over time. Strongly non-linear material property relationships are usually represented using diagrams. In numerical calculations, these diagrams are analyzed in order to take into account the coupling between the properties. An example of these types of material properties is the dependence of the kinetics of phase transformations in the solid state on the rate and history of temperature change. In literature, these data are visualized Continuous Heating Transformation (CHT) and Continuous Cooling Transformation (CCT) diagrams. Therefore, it can be concluded that time series analysis is important in numerical modeling. This analysis can also be performed using neural networks. This work presents a new approach to storing and analyzing the data contained in the discussed CCT diagrams. The application of Long-Short-Term Memory (LSTM) neural networks and their architecture to determine the correct values of phase fractions depending on the history of temperature change was analyzed. Moreover, an area of research was elements that determine what type of information should be stored by LSTM network coefficients, e.g., whether the network should store information about changes of single phase transformations, or whether it would be better to extract data from differences between several networks with similar architecture. The purpose of the studied network is strongly different from typical applications of artificial neural networks. The main goal of the network was to store information (even by overfitting the network) rather than some form of generalization that allows computation for unknown cases. Therefore, the authors primarily investigated in the ability of the layer-based LSTM network to store nonlinear time series data. The analyses presented in this paper are an extension of the issues presented in the paper entitled “Model of the Austenite Decomposition during Cooling of the Medium Carbon Steel Using LSTM Recurrent Neural Network”. 相似文献
52.
我们采用RP-HPLC方法研究了SD纯系雄性大鼠冷适应期间脑垂体(P)、下丘脑(HT)和血浆(BP)生物活性肽变化。冷适应期间P、HT和BP肽类(MW≤30000)RP-HPLC图谱均出现一些新的肽洗脱峰。而且,所有这些肽类都能增强淋巴细胞(LC)转化活性。在P和HT肽类刺激下,脾LC[~3H]-TdR参入分别增加725 cpm(P<0.01)和1274 cpm(P<0.001)。将这些肽类进一步经Sep-Pack C_(18)柱纯化后仍分别增加[~3H]-TdR参入cpm值597(P<0.05)和333。这些结果表明了免疫系统(ImS)与神经内分泌系统(NES)双向调节环路的一个方面:NES作用于ImS。 相似文献
53.
Yongming Yan Yanjun Xue Wenchao Yu Ke Liu Maoqiu Wang Xinming Wang Liuqing Ni 《Materials》2022,15(12)
This paper focuses on the effect of gear steel on distortion due to phase transformation in carburizing and quenching. The carburizing and quenching process of C-rings under suspension was studied by using the finite element method based on the thermo-mechanical theory, considering phase transformation. The phase transformation kinetics parameters, depending on different carbon contents, were measured by Gleeble-3500. The distortion behavior of the carburized C-ring during the cooling stage was analyzed, as well as the carbon concentration distribution and martensite volume fractions. The accuracy of the simulation was also verified by comparing the experimental data with the simulated result of the distortion and microstructure. A reliable basis is provided for predicting the distortion mechanism of gear steels in carburizing and quenching. 相似文献
54.
目的观察中药复方扶正解毒含药血清(FJD)对硫酸镍(NiSO4)诱导培养人支气管上皮(16HBE)细胞恶性转化的抑制作用。方法NiSO4多次处理16HBE细胞,利用刀豆凝集素A(ConA)凝集实验和软琼脂集落形成实验进行转化细胞的恶性鉴定;同时添加不同剂量的FJD,观察其抗转化效应。结果NiSO4(400μmol/L)染毒8次(20代)时,细胞生长速度加快,排列紊乱,失去接触抑制,出现复层生长,可被ConA凝集,并可在软琼脂上生长。3种剂量FJD与NiSO4共处理组细胞转化率分别为0.82%、0.47%和0.19%,明显低于单用NiSO4组(4.13%),且呈剂量-效应关系(r=-0.884,P<0.01),细胞ConA凝集反应阴性,不能在软琼脂上生长。结论体外实验显示,FJD具有抑制NiSO4诱导16HBE细胞恶性转化的作用。 相似文献
55.
Investigations of excess environmental risks around putative sources: statistical problems and a proposed test 总被引:14,自引:0,他引:14
R A Stone 《Statistics in medicine》1988,7(6):649-660
Individual reactions to a report which identifies an excess of risk near a putative source are determined mainly by some quoted significance level. One reaction, involving a commonly used 'coincidence' argument is given a simple Bayesian explanation. It is argued that interpretations of such reports should if possible allow both for data selection and for uncertainty in the null expectations underlying the significance levels. Tests are proposed, based on the first isotonic regression estimator under an order restriction, which allow for the effects of selecting a study region in the light of the data and have a simple form. Data on cancer incidence around two nuclear plants are used to illustrate. 相似文献
56.
目的 探究长链非编码RNA(lncRNA)核富集转录体1(NEAT1)NEAT1对喉鳞状细胞癌(LSCC)细胞迁移和侵袭的影响,并进一步分析miR-429/锌指E-盒结合同源异形盒1(ZEB1)轴在其中发挥的作用。方法 慢病毒转染建立稳定敲减lncRNA NEAT1的LSCC细胞,通过RT-qPCR检测细胞lncRNA NEAT1表达以验证转染效率,通过Transwell实验检测细胞迁移和侵袭能力,通过Western blot检测细胞上皮-间充质转化(EMT)相关蛋白N-cadherin、Vimentin、Slug和Snail表达。通过生物信息学分析miR-429与lncRNA NEAT1和ZEB1 mRNA间的潜在结合位点,并通过双荧光素酶报告基因实验验证miR-429与lncRNA NEAT1以及miR-429与ZEB1 mRNA结合。将miR-429抑制剂转染敲减lncRNA NEAT1的LSCC细胞,通过Western blot检测细胞ZEB1表达。进一步检查敲减ZEB1对抑制miR-429的敲减lncRNA NEAT1的LSCC细胞迁移、侵袭和EMT的影响。结果 敲减lncRNA NEAT1降低LSCC细胞lncRNA NEAT1表达,抑制细胞迁移和侵袭并下调细胞N-cadherin、Vimentin、Slug和Snail表达。miR-429与lncRNA NEAT1和ZEB1 mRNA间存在潜在结合位点,且miR-429与lncRNA NEAT1以及miR-429与ZEB1 mRNA结合。抑制miR-429逆转了敲减lncRNA NEAT1对LSCC细胞ZEB1表达的抑制作用。此外,敲减ZEB1逆转了抑制miR-429对敲减lncRNA NEAT1的LSCC细胞迁移和侵袭的促进作用及EMT相关蛋白N-cadherin、Vimentin、Slug和Snail表达的上调作用。结论 lncRNA NEAT1促进LSCC细胞迁移和侵袭,其机制可能与海绵化miR-429上调ZEB1表达促进LSCC细胞EMT有关。 相似文献
57.
William A. Grissom Michael Lustig Andrew B. Holbrook Viola Rieke John M. Pauly Kim Butts‐Pauly 《Magnetic resonance in medicine》2010,64(4):1068-1077
Temperature estimation in proton resonance frequency (PRF) shift MR thermometry requires a reference, or pretreatment, phase image that is subtracted from image phase during thermal treatment to yield a phase difference image proportional to temperature change. Referenceless thermometry methods derive a reference phase image from the treatment image itself by assuming that in the absence of a hot spot, the image phase can be accurately represented in a smooth (usually low order polynomial) basis. By masking the hot spot out of a least squares (?2) regression, the reference phase image's coefficients on the polynomial basis are estimated and a reference image is derived by evaluating the polynomial inside the hot spot area. Referenceless methods are therefore insensitive to motion and bulk main field shifts, however, currently these methods require user interaction or sophisticated tracking to ensure that the hot spot is masked out of the polynomial regression. This article introduces an approach to reference PRF shift thermometry that uses reweighted ?1 regression, a form of robust regression, to obtain background phase coefficients without hot spot tracking and masking. The method is compared to conventional referenceless thermometry, and demonstrated experimentally in monitoring HIFU heating in a phantom and canine prostate, as well as in a healthy human liver. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc. 相似文献
58.
A 60-year-old man, who suffered from advanced rectal cancer accompanied with liver metastasis, underwent an abdominoperineal
resection and a partial hepatectomy. He remained well until 4 months after surgery when he developed a biopsy-proven recurrent
intrapelvic mass and multiple liver tumors. At 6 months after surgery, the metastatic liver tumors grew larger and almost
completely occupied both lobes of the liver. However, 9 months after surgery, the liver tumors regressed remarkably and his
clinical condition improved without any specific treatment for cancer. Although he died of cancerous peritonitis 18 months
after surgery, the autopsy findings did not indicate any apparent regrowth of the liver tumors. To date, only one case report
of a spontaneous regression of a metastatic liver tumor from colorectal cancer has been published in the English literature.
We herein describe this rare case and discuss some of the reasons potentially responsible for the regression.
Received: July 16, 2001 / Accepted: March 5, 2002 相似文献
59.
通过对上皮间质转化理论基础的回顾,探讨上皮间质转化、间质上皮转化与肝脏纤维化及肝癌干细胞转化的关系,从而寻找肝癌干细胞的相关基因、抗体标记物及关键通路,这不仅有利于肝细胞癌分期的诊断,提示预后,更为寻找医治肝癌的方法提供更多的研究方向。 相似文献
60.