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With the improvement of the quality and performance requirements of duplex stainless steel （DSS） in the industry， secondary austenite （γ2） has become one of the key factors affecting the application of S32750 DSS. Secondary austenite is considered as the joint product of temperature and cooling rates， which performed near K-S or N-W orientation relationship with the ferrite phase and an enrichment for N elements .Secondary austenite can be divided into needle-shaped austenite （NA） and isolated austenite （IA） by morphology. In this paper， the effect of N mass fraction on the precipitation behavior of secondary austenite was studied by preparing test steels with N content of 0.02%， 0.09% and 0.17%. Thermal-Calc simulation and EBSD detection proved that with the increase of N， γ2 evolved from curved feather-shape to needled-shape with the total proportion of austenite phase increased. The precipitation mode of austenite related to the Gibbs free energy， which was namely affected by elements composition and temperature.

In this paper, the research findings on erosion - corrosion of metal materials at home and abroad in recent years were mainly summarized, including research methods of erosion corrosion and external factors affecting erosion corrosion rate. At present, the research methods of erosion - corrosion were mainly carried out in the form of experimental method, supplemented by numerical simulation. The experimental methods primarily included the classification of experimental devices and the collection and characterization of experimental results. Besides, the influencing factors affecting the erosion corrosion rate were classified and compared. The main influencing factors included flow velocity, sand content, sand size， impact angle, liquid pH value, temperature, oxygen content, etc. In the future, the main developing directions of erosion - corrosion would be the following aspects: optimizing the structure of numerical model to predict the erosion - corrosion rate distribution diagram of materials and determining the weak areas of multiphase flow erosion - corrosion.

In the current information age, having more data means having more information. However, the complete sharing of data will increase the possibility of criminals using relevant data to commit crimes. With the development of cloud computing technology, data sharing can be realized based on the cloud, and the shared data can be stored in the data center. However, this will not ensure the security and privacy of the shared data, and there are security risks such as tampering and counterfeiting of the shared data. The decentralization of the blockchain and the non-tamperable characteristics of the data on the block can safely save data-sharing records without the need for a trusted third party. The paper will discuss the decentralized trusted data sharing technology based on blockchain to enhance the credibility of data sharing. This paper will use the characteristics of the decentralized trust management of the blockchain to study the decentralized solution of trusted data sharing. Aiming at the storage problem of shared data, the block structure of shared data oriented to the blockchain is proposed, and the design is based on the blockchain, and the information of the shared data is stored in the blockchain; in response to the data access request and service problem in data sharing, a block chain-based, decentralized data sharing mechanism is proposed; usingsmart contracts can adopt data variables as parameters to transfer and store the characteristics. Design a decentralized, trusted data sharing smart contract, form a blockchain-based data sharing prototype system, and finally simulate the real on the Ethereum open source platformScenes. The data sharing system based on blockchain was simulated and run on the Ethereum blockchain platform, and the data sharing function test was carried out. Experiments have shown that the blockchain-based data sharing technology solution in a decentralized application environment and distributed storage of data to protect data security, to a certain extent, enhance the credibility of data sharing. [ABSTRACT FROM AUTHOR]

BACKGROUND. Retropharyngeal lymph node (RLN) metastases have profound prognostic implications in patients with nasopharyngeal carcinoma (NPC). However, the AJCC staging system does not specify a size threshold for determining RLN involvement, resulting in inconsistent thresholds in practice. OBJECTIVE. The purpose of this article was to determine the optimal size threshold for determining the presence of metastatic RLNs on MRI in patients with NPC, in terms of outcome predictions. METHODS. This retrospective study included 1752 patients (median age, 46 years; 1297 men, 455 women) with NPC treated by intensity-modulated radiotherapy (RT) from January 2010 to March 2014 from two hospitals; 438 patients underwent MRI 3-4 months after treatment. Two radiologists measured the minimal axial diameter (MAD) of the largest RLN for each patient using a consensus process. A third radiologist measured MAD in 260 randomly selected patients to assess interobserver agreement. Initial ROC and restricted cubic spline (RCS) analyses were used to derive an optimal MAD threshold for predicting progression-free survival (PFS). The threshold's predictive utility was assessed in multivariable Cox regression analyses, controlling for standard clinical predictors. The threshold's utility for predicting PFS and overall survival (OS) was compared with a 5-mm threshold using Kaplan-Meier curves and log-rank tests. RESULTS. The intraclass correlation coefficient for MAD was 0.943. ROC and RCS analyses yielded an optimal threshold of 6 mm. In multivariable analyses, MAD of 6 mm and greater independently predicted PFS in all patients (HR = 1.35, p = .02), patients with N0 or N1 disease (HR = 1.80, p = .008), and patients who underwent posttreatment MRI (HR = 1.68, p = .04). In patients with N1 disease without cervical lymph node involvement, 5-year PFS was worse for MAD greater than or equal to 6 mm than for MAD that was greater than or equal to 5 mm but less than 6 mm (77.2% vs 89.7%, p = .03). OS was significantly different in patients with stage I and stage II disease defined using a 6-mm threshold ( p = .04), but not using a 5-mm threshold ( p = .09). The 5-year PFS rate was associated with a post-RT MAD of 6 mm and greater (HR = 1.68, p = .04) but not a post-RT MAD greater than or equal to 5 mm (HR = 1.09, p = .71). CONCLUSION. The findings support a threshold MAD of 6 mm for determining RLN involvement in patients with NPC. CLINICAL IMPACT. Future AJCC staging updates should consider incorporation of the 6-mm threshold for N-category and tumor-stage determinations.