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He-yun Bao,Weidi Kong,Xiaonan Hou,Rupeng Zhu 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.8
To examine the influence of the groove shape of a friction disk on the transient temperature field in the engagement process of aviation wet friction clutch, a transient thermal analysis model of friction clutch was established, and the application method of thermal boundary conditions, including the calculation of convective heat transfer coefficient and heat flux density, was studied. The transient heat loading process was established by the partition method of friction disk and steel disk. The temperature characteristics of wet clutch friction pairs with different groove shapes during the engagement process were analyzed and tested on an SAE#2 testing machine. Results show that when the clutch is engaged, the temperature of the friction pair composed of two-way parallel groove, three-way parallel groove, and waffle groove friction disk increases continuously at first and finally decreases slightly; the highest temperature of the friction disk and steel disk is at the ring near the outer ring of the friction disk;and the waffle groove friction disk is more suitable for aviation wet friction clutch.
Yuan Li,Weidi Wang,Xirun Wan,Fengzhi Feng,Yong-Lan He,Junjun Yang,Yang Xiang 대한부인종양학회 2022 Journal of Gynecologic Oncology Vol.33 No.3
Objective: To investigate the clinical characteristics, treatments, and prognostic factors among patients with gestational trophoblastic neoplasia (GTN) exhibiting brain metastases who underwent craniotomy. Methods: Thirty-five patients with GTN who had brain metastases and subsequently underwent craniotomies between January 1990 and December 2018 at Peking Union Medical College Hospital were identified using the GTN database. Their clinical manifestations, treatments, outcomes, and prognostic factors were retrospectively analyzed. Results: All 35 patients underwent decompressive craniotomy, hematoma removal, and metastatic tumor resection combined with multiagent chemotherapy. Eighty percent (28/35) achieved complete remission, 11.4% (4/35) achieved partial remission, and 8.6% (3/35) had progressive disease. Not counting 2 patients who were lost to follow-up, 81.8% of the patients (27/33) were alive after a median follow-up of 72 months. The 5-year overall survival rate was 80.4%. Univariate analysis revealed that a history of chemotherapy failure (p=0.020) and a >1-week interval between craniotomy and chemotherapy commencement (p=0.027) were adverse risk factors for survival. Multivariate analysis showed that previous chemotherapy failure remained an independent risk factor for poor survival (odds ratio=11.50; 95% confidence interval=1.55–85.15; p=0.017). Conclusion: Decompressive craniotomy is a life-saving option if metastatic hemorrhage and intracranial hypertension produce a risk of cerebral hernia in patients with GTN who have brain metastases. Higher survival rates and improved prognoses can be achieved through perioperative multidisciplinary cooperation and timely standard postoperative chemotherapy.
Hongming Wu,Dinghong Xu,Ying Zhou,Chengtao Gao,Jianbing Guo,Weidi He,Yong He,Shuhao Qin 한국섬유공학회 2020 Fibers and polymers Vol.21 No.9
Natural fibers reinforced composites (NFCs) have renewable and low cost advantages. In this paper, the tung oilanhydride (TOA) modified polypropylene (PP)/hemp fiber composites have been prepared by a melt-blended process. Thereaction between the tung oil anhydride and the as-treated hemp fiber make the TOA molecules to accumulate on the surfaceof hemp fiber and to form a TOA layer on the surface of hemp fibers, which is confirmed by the FT-IR and SEM analyses. The TOA layer improves the compatibility between PP matrix and hemp fibers. The elongation at break (EB) and impactstrength of the PP/hemp fiber/TOA composites are twice more than the PP/hemp fiber composites. Thermal analysis showsthe Toneset and Tmax of the composites increasing that reflects the thermal stability of the composites improved. The crystallineproperty reveals that the Tc moves to high temperature with the TOA or hemp fiber added in the blends. The DMA andrheology properties analysis indicate that the TOA layer improved molecular mobility of the composites and show a shearthinning effect.