Investigating the Influences of Wet Fiber Laser Cutting Upon the Surface Integrity of Nitinol Cardiovascular Stents

Xiaoyu Sun,Xiuting Wei,Zhiyong Li,Deda Lou,Yongqi Wang,Hanqing Liu 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.22 No.7

High precision laser cutting with minimal post-treatment is needed in the manufacturing of nitinol cardiovascular stents. This paper carries out a series of cutting experiments of nitinol cardiovascular stents by wet fiber laser cutting to understand the basic process characteristics and to investigate the influences of process parameters (laser power, cutting speed, pulse width, frequency) upon the surface integrity (surface topography, dross, surface roughness, HAZ, recast layer, subsurface nanohardness, surface chemical composition). The univariate analysis was used to analyze and explain the influence that rules of process parameters had upon the surface integrity. The experiment results showed that the effects of process parameters on surface integrity were regular, with the optimal single-factor parameters obtained. Moreover, the removal mechanism of the nitinol material was also revealed. This study is of great significance for the medical industry in improve the cutting quality of cardiovascular stents.

누가 백신을 맞는가: 기술수용모형(TAM)으로 살펴본 중국인들의 COVID-19 백신접종 결정요인들

손우비 ( Sun¸ Yufei ),호함경 ( Hu¸ Hanqing ),김태용 ( Kim¸ Taeyong ) 경희대학교 사회과학연구원 2021 社會科學硏究 Vol.47 No.1

본 연구는 기술수용모형을 이론적 틀로 삼아 접종의도의 개념과 그것에 영향력이 있을 것으로 예상되는 다양한 개념들을 측정하는 복수의 문항들로 구성된 설문을 통해 중국인들의 COVID-19 백신 접종의도를 결정하는 요인들이 무엇이었고 그 영향구조는 어떠한가를 규명하는 것을 목적으로 수행되었다. 중국 현지에서 수행된 조사 결과를 다각도로 분석한 연구자들은 다음과 같은 결론을 도출할 수 있었다: 첫째, 용이성은 무의미하며, 유용성 지각이 접종의도 형성에 중심역할을 한다. 백신은 분명 신기술이고 따라서 기술수용모형의 적용이 가능해야 하지만, 접종이라는 행동은 그 난이도가 현저히 낮아, 용이성이 큰 의미를 갖지 못한 것으로 해석된다. 둘째, 모든 영향의 원천은 건강관련 지식(헬스리터러시)과 위험지각(지각된 위험)으로 압축된다. 위험지각이 인간이 수집해 축적하는 관련 지식들에 의해 결정된다는 점을 상기할 때, 이는 대중을 대상으로 하는 국가 차원의 교육이 무엇보다 중요함을 시사한다. 셋째, 주관적 규범은 그 자체가 유용성과 접종의도에 미치는 영향에 더해, 헬스리터러시와 접종의도 그리고 지각된 위험과 접종의도 사이에서 의미 있는 중개역할을 한다. 또 하나의 주목할 만한 발견은 주관적 규범이 유용성에 미치는 긍정적 영향이 지각된 위험이 유용성에 미치는 부정적 영향보다 훨씬 크다는 사실이다. 본 연구는 기술수용모형이 백신접종 상황에도 적용이 가능하다는 점을 밝힌 이론적 의의에 더해, 정부가 ‘2021년 11월 국가 집단면역 완성’을 이루기 위해 무엇을 시도할 수 있는지를 제안해준 실무적 의의를 갖는다. The present study was performed to identify what factors determine the intention of Chinese people to get a COVID-19 vaccine and its effect structure with the data collected from an on-line survey conducted in China by employing the Technology Acceptance Model(TAM). The present researchers carried out a series of analyses with the data to draw the conclusions as follows: First, perceived ease of use seems meaningless in the situation in which the target behavior was to get a vaccine, while perceived usefulness played a central role in the formation of such intention. Second, all the impacts seemed derived from people’s health literacy and perceived risk. Third, in addition to its own influence on usefulness and intention, subjective norm plays a significant mediating role between health literacy and intention and between perceived risk and intention. Finally, noteworthy is that the positive impact of subjective norm on usefulness is far greater than the negative impact of perceived risk, meaning that meeting the expectations of those they value and care is considered much more useful than avoiding the risk they are to face. In addition to the theoretical significance of revealing that the TAM can be applied to an inoculation situation, this study has practical significance suggesting what the government can do in order to achieve its goal of completing national immunity by November 2021.

Thermal Gradient–Dependent Strain Behavior of Contacted Soil Specimens Subjected to Freeze–Thaw

Xiaodong Zhao,Zhiyuan Lv,Hanqing Sun 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.3

Soil specimens were initially prepared by freezing with a thermal gradient (Fnonuni) and then thawing under uniform temperature (Tuni), then the strain behaviors of which using digital processing technique (DPT)–aided unconfined compression on contacted specimens were investigated. Although the specimen treated under Fnonuni - Tuni exbihted a strength over 1.8 times higher and a specimen scale–based (S–) lateral strain over 0.3 times smaller than that treated under freeze–thaw with uniform temperatures Funi - Tuni, it exhibited a relatively greater local scale–based (L–) strain level under identical S–axial strain, and dominated the deformation process of the specimen assembly. The characteristic of L–strain relationship between top and bottom specimens under Fnonuni - Tuni and specimens under Funi - Tuni approached identical when S–axial strain exceeded a threshold corresponding to the peak strength. Further, an asymmetric L–strain gradient at two sides of the fractured surface in specimens was observed, and it was more evident in specimens treated under Fnonuni - Tuni. These test data and observations obtained have been validated by detailed comparisons with previous studies, and contribute to build a constitutive model considering nonlocal variable and thus improve the settlement prediction precision of the thawed soils.

Protective strategy for the caudate lobe bile duct during left hemihepatectomy based on imaging data analysis

Zhengyi Wu*,Liang Sun*,Ke Ning,Zhendong Chen,Zhipeng Wu,Hanqing Yang,Jinlong Yan*,Xiangbao Yin* 대한외과학회 2023 Annals of Surgical Treatment and Research(ASRT) Vol.105 No.6

Purpose: This study was performed to analyze the rule of confluence of the caudate lobe bile duct (CLD) into the left hepatic duct (LHD) and to discuss the protective strategy during left hemihepatectomy. Methods: MRI of 400 patients and T-tube angiography images of 100 patients were collected, and the imaging rules of the confluence of the CLD into the LHD were summarized. The clinical data of 33 patients who underwent left hemihepatectomy using the protective strategy were analyzed. Results: MRI and T-tube angiography images showed that the length from the confluence point of the CLD into the LHD to the confluence of the left and right hepatic ducts was 1.19 ± 0.40 cm and 1.26 ± 0.39 cm, respectively. The average angle between the longitudinal axis of the 2 bile ducts was 68.27° ± 22.59° and 66.58 ± 22.88°, respectively. Coronal and cross-sectional images showed that inflow from the foot side to the cranial side was noted in 79.8% and 82.0% of patients, respectively, and inflow from the dorsal to the ventral side was observed in 84.5% and 88.0%, respectively. Based on these imaging rules, the safe transection length and plane were summarized, and the CLD was effectively protected in 33 cases of left hemihepatectomy. Conclusion: In left hemihepatectomy, the LHD should be transected at least 1.5 cm away from the confluence of the left and right hepatic ducts, and the plane of transection should be oblique to the dorsal side at an angle of 45° with the LHD, these parameters represent an effective strategy to protect the CLD.

Effects of confinement on physiological and psychological responses and expression of interleukin 6 and brain derived neurotrophic factor mRNA in primiparous and multiparous weaning sows

Zhang, Mingyue,Li, Xiang,Li, Jianhong,Sun, Hanqing,Zhang, Xiaohui,Bao, Jun Asian Australasian Association of Animal Productio 2017 Animal Bioscience Vol.30 No.9

Objective: The present study aimed to investigate whether the long-lasting, recurrent restricting of sows leads to the physiological and psychological reaction of discomfort. Methods: Sows (Large White) that had experienced restricting for about 0.5 or 3 years and agematched sows kept in a group housing system (loose sows) were compared. Pupillary light reflex parameters were measured at the weaning stage. Immediately after slaughter, blood samples were taken to measure serum cortisol levels, and the brain was dissected, gene expression in the hippo-campus, frontal cortex and hypothalamus was analyzed. Results: The serum cortisol levels were higher in the confined sows than in the loose sows. The full maturity, but not the young adolescent, confined sows had longer latency time in the onset of pupil constriction than their loose counterparts. Real-time polymerase chain reaction analyses revealed an increased expression of interleukin 6 mRNA in the hippocampus and decreased expression of brain derived neurotrophic factor mRNA in hippocampus and hypothalamus and to a lesser extent in the frontal cortex of the full maturity confined sows, compared with the full maturity loose sows. Conclusion: Taken together, these data indicated that recurrent restricting stress in full maturity sows leads to the physiological and psychological reaction of discomfort.