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The HI-13 tandem accelerator, located at the Beijing Tandem Accelerator National Laboratory, has been in operation for 35 years. To ensure the continued performance of the accelerator, the operation and maintenance team has prioritized focus on various aspects. The operation team conducted research that involved developing key components, cultivating a high-quality operational team, improving the machine time efficiency, and increasing the participation of users outside the China Institute of Atomic Energy (CIAE). The primary emphasis has been on developing key components and upgrading subsystems. These efforts have successfully maintained and improved the accelerator's performance, ensuring its safe and stable operation. Finally, the paper alse discusses the challenges faced by tandem accelerators and presents future development plans.

Bolted composite joints are one of the most common joining methods used in aerospace industry for joining of parts and sub-assemblies, where there is a need to transfer high load with consistency and easy to assemble/ dissemble of parts for maintenance. Bolted connection undergoes different types of vibrations during their service life, that make the pre-load on bolted joints to decrease and call for increase in dynamic loading and failure. Regular checking and tightening of bolted joints become a crucial and expensive activity to maintain the structure to perform efficiently. The natural frequency is one of the most important factors of vibration of structure that depends on the geometry and material properties of the structure. In this paper, the effect of pre-load and temperature on the natural frequency of single bolted and double-bolted joints is investigated experimentally and numerically. [ABSTRACT FROM AUTHOR]

Tensile experiments were conducted with single-bolted and multi-bolted countersunk composite-metal joints. The finite element models with Hashin criteria and modified Camanho degradation law were developed to predict the bearing load and to simulate the failure behavior. The models were validated with the experimental results, including load-displacement curves and composite damage profiles. Based on the verified models, bolt load distributions of multi-bolted joints were calculated and analyzed before and after damage occurs. Results show that composite damages can change the bolt load distributions to a certain extent, which needs to be considered during the structure design. To adjust the bolt load distribution, the effects of joint variables, including bolt-hole clearance, bolt spacing, countersunk height ratio, and bolt stiffness combination, have been studied. It is found that the increase of the pin clearance around the largest bearing bolt would decrease its corresponding bearing load. The countersunk height ratio affects the bolt load distribution difference that a greater ratio leads to a less difference. The bolt spacing and bolt stiffness can also be used to reduce the bolt load distribution difference with elaborately designed combinations. [ABSTRACT FROM AUTHOR]

Focuses on the guidelines for the diagnosis and treatment of inflammatory bowel disease. List of diagnostic criteria; Difference between the diagnosis of Crohn's disease and intestinal tuberculosis; Indicators of surgery.

Objective: To observe the effect of Na-butyrate on trinitrobenzene sulfonic acid (TNBS) induced rat colitis and discuss its mechanism., Methods: 0.85 ml of 50% ethanol enema containing 30 mg TNBS was instillated into rat colon to produce distal colitis. On the 5th day after TNBS enema, the rats were divided into 3 groups and were given respectively 100 mmol/L Na-butyrate, 100 mg/kg SASP or 0.9% saline enema daily. On the 19th day, macroscopical, histological injury scores of colonic mucosa and tissue myeloperoxidase (MPO) activity were evaluated, and the mitotic index in Na-butyrate group was compared with that in SASP group., Results: Diarrhea was apparently improved, weight gain was not apparently different, the scores of macroscopical and histological injury and MPO activity decreased in the SASP group and the Na-butyrate group, compared with the control (P < 0.05). However, there was not obvious difference between the Na-butyrate group and SASP group (P > 0.05). Mitotic index in Na-butyrate group was higher than that in SASP group (P < 0.05)., Conclusion: Na-butyrate enema can expedite the restoration of the experimental colitis, and its therapeutic effect is as good as that of SASP.

Objective: This study was conducted to assess the growth inhibition of colorectal adenoma cells by sulindac and identify the possible mechanisms., Methods: The colorectal adenoma cells from human sporadic adenomatous polyps were cultured, and then treated with sulindac. The cell viability was examined by MTT colorimetric assay; the S-phase fraction and the percentage of apoptosis were measured by flow cytometry., Results: Following sulindac treatment at different concentrations for 24, 48 and 72 hours, reduction of the cell viability was time- and dose-dependent. After 48-hour-treatment, S-phase fraction was decreased and the percentage of apoptosis was increased; both indexes of all groups except 0.3 mmol/L group were different from those of controls (P < 0.05)., Conclusion: These data suggested that sulindac could inhibit the growth of the colorectal adenoma cells, and its mechanisms might be related to suppressing proliferation and inducing apoptosis.