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The epicenter of the Ms6.0 earthquake occurred near Shuanghe Town in the southeast of Changning County, Yibin, Sichuan Province On June 17, 2019 is with the intensity of VIII degree. Immediately after the earthquake, field investigation of geological disasters were conducted, and it was found that Changning County and Gongxian County were greatly affected by the earthquake, while other districts and counties were slightly impacted. Based on the survey before and after the earthquake in three districts and seven counties in Yibin City, combined with the seismic intensity map and news articles issued by Sichuan Provincial Seismological Bureau, the development and distribution characteristics of post earthquake geological disasters in different seismic intensity areas, are as follows: ① The magnitude of the “6·17” earthquake in Changning, Yibin is 6.0, and the order of magnitude is 6.0. But there are many kinds of geological disasters. ②New geological hazards mainly distributed in Shuanghe Town, Changning County. The density of geological hazards in high intensity area is much larger than that in low intensity area. ③ The potential disaster points increased in high intensity areas, but slightly increase in medium intensity areas and had no change in low intensity areas. The conclusion of this paper could be reference for Sichuan Province, especially for the emergency relief, construction planning and geological disaster prevention and control.

To solve the problem of high sintering temperature of vitrified bond, a novel low- temperature vitrified bond based on Bi2O3-B2O3 glass system was proposed. The effect of nano-SiC and nano-ZrO2 on the phase composition, fluidity and mechanical properties of the vitrified bond were analyzed. Additionally, the effect of adding walnut shell powder as a pore-forming agent on the microstructure of the vitrified bond diamond grinding wheel was explored. A vitrified bond diamond cup grinding wheel based on Bi2O3-B2O3 glass system was prepared, and its grinding performance on monocrystalline silicon wafer was tested. The results show that adding nano-SiC powder leads to the formation of Bi in the vitrified bond and destroys the [BiO4] glass network of vitrified bond. The fluidity of the vitrified bond decreases with the addition of nano-SiC and nano- ZrO2. Furthermore, the fluidity, flexural strength and hardness of the vitrified bond increase as the sintering temperature increases. The flexural strength and the hardness of the vitrified bond reach to their highest value at 560 ℃. With the increase of the content of the pore-forming agent, the amount of large pores in the grinding wheel increases significantly and the size becomes larger. The prepared Bi2O3-B2O3 vitrified bond diamond cup grinding wheel (800 mesh or M10/20) was used to grind monocrystalline silicon wafer under specific conditions (linear speed: 12.56 m/s, workpiece speed: 5.23 m/s, and feed speed: 0.1 μm/s). The grinding ratio reaches 790, and the surface roughness of the monocrystalline silicon wafer is 0.16 μm.

The effect of the content and the size (0.2, 0.4, 0.6 mm) of the hollow corundum microspheres on the total porosity, the flexural strength, the hardness and the microstructure of vitrified bond was investigated. The ceramic bonded diamond grinding wheel with hollow alumina microspheres as pore forming agent was prepared, and the grinding performance of the grinding wheel on quartz glass was studied. The results show that with the increase of the content of hollow corundum microspheres, the porosity increases, and the flexural strength and the hardness decreases at the same time. With the same content of hollow corundum microspheres, addition the smaller size of microspheres could lead to the increase of the porosity and the decrease of flexural and hardness. The vitrified bond diamond wheel contained with hollow corundum microspheres can used to grind quartz glass, and the surface roughness can be reduced from 0.5113 μm to 0.0206 μm. Diamond wheel contained with hollow corundum microspheres can used to grind quartz glass, and the surface roughness can be reduced from 0.5113 μm to 0.0206 μm.

Objective To investigate the risk factors and preventive strategies of pancreaticoduodenectomy postoperative hemorrhage. Methods A total of 208 patients who underwent pancreaticoduodenectomy in the Department of Hepatobiliary Surgery of the 904th Hospital of Joint Logistics Support Force, PLA from January 2017 to December 2021 were enrolled. Twenty-one patients with postoperative hemorrhage were retrospectively analyzed. Results Univariate analysis indicated that postoperative hemorrhage was mainly associated with pancreatic leakage, biliary leakage, abdominal infection, hypoproteinemia, diabetes, improper use of ultrasound knife, skeletonization, intraoperative blood loss, preoperative jaundice, etc.(P0.05). Among the 21 patients with postoperative hemorrhage, 4 cases recovered after conservative treatment such as hemostasis and blood transfusion, 6 cases underwent interventional treatment, 11 cases underwent abdominal exploration, and 2 cases died of postoperative multiple organ failure. Pancreatic leakage (OR=3.963,95%CI: 1.120-14.025), biliary leakage (OR=4.013,95% CI: 1.173-13.734) and abdominal infection (OR=7.545,95%CI: 1.833-31.051) were independent risk factors for postoperative hemorrhage. Conclusions The improvement of anastomotic manipulation, reduction of anastomotic leakage, and control and prevention of abdominal infection are important to prevent postoperative hemorrhage of pancreaticoduodenectomy. Surgical treatment should be performed as soon as possible for the patients with poor conservative treatment effect.