Investigation on the machinability of polycrystalline ZnSe by elliptical vibration diamond cutting.

Polycrystalline zinc selenide is widely used in advanced optical systems due to its superior optical properties. However, the soft and brittle properties bring a challenge for high-quality surface processing. In recent years, elliptical vibration cutting has been proven as a promising method for machining brittle materials. In the present research, a series of grooving and planning experiments were carried out to investigate the machinability of zinc selenide with elliptical vibration cutting. The removal mechanism was analyzed from fracture characteristics, chip morphology, and phase transformation. The results show that elliptical vibration cutting is effective in suppressing cleavage-induced craters. Reducing the nominal cutting speed is beneficial to inhibit the spring back-induced tearing of grains. A 94-time increase in the critical depth of cut was achieved by vibration trajectory optimization compared to ordinary cutting. Moreover, the influence mechanism of feed on the evolution of surface morphology was revealed. Finally, a zinc selenide microlens array was successfully fabricated. The performance was evaluated by geometric parameter measurements and a multiple imaging test. The findings provide a prospective method for ductile regime machining of zinc selenide.

Transcatheter arterial chemoembolization combined with microwave coagulation therapy and the perioperative care for patients with hepatocellural carcinoma.

PURPOSE: To explore the value of artificial hydrothorax microwave coagulation combined with transcatheter arterial chemoembolization (TACE) therapy in the treatment of ultrasound-invisible malignant tumors in the hepatic dome (mainly hepatocellular carcinoma/HCC) and the perioperative care for the patients. METHODS: Sixty-eight patients with malignant liver tumors in the hepatic dome were treated with a combination therapy of TACE and microwave coagulation via an artificially induced hydrothorax. Their perioperative condition was under close observation and the nursing care was intensified. Paracentesis of the chest was successfully carried out via the positioning of ultrasound and guidance of microwave to the tumor site, so that the tumor could be treated with cold cycle microwave coagulation therapy. RESULTS: After treatment, 3/68 patients (4.4%) achieved complete tumor ablation, while 59/68 (86.8%) achieved tumor ablation >50% or tumor shrinkage >30%. Another 6/68 patients (8.8%) achieved tumor ablation <50% or tumor shrinkage <30%. Of 45 patients, 42 (93.3%) obtained a reduction of AFP level >50% post-therapy, 28/37 patients (75.7%) achieved a reduction of CEA level >50%, 23/29 patients (79.3%) achieved a reduction of CA19-9 level> 50%; 3/68 patients (4.4%) survived for 4 to 6 months, 31/68 (45.6%) survived >6 months and 34/68 (50%) survived >12 months. No bleeding, liver failure, infection or needle tract seeding occurred after the operation, and no treatment-related deaths occurred. CONCLUSION: Microwave coagulation combined with TACE for HCC in the hepatic dome is safe and effective. Perioperative observation and nursing care can not only reduce the complications but also improve the therapeutic effect and the patient quality of life.