Push-out tests on stud shear connectors with constrained structure of steel-concrete composite beams

Jingjing Qi,Zuwei Xie,Hua Cao,Zhi Huang,Weirong Lv,Weihua Shi 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.83 No.6

The stud shear connector is the main force transfer member in the steel-concrete composite member, and the mechanical behavior is very complicated in the concrete. The concrete around the stud is subjected to the pry-out local pressure concentration of the stud, which can easily produce splitting mirco-cracks. In order to solve the problem of pry-out local splitting of stud shear connector, a kind of stud shear connector with constraint measure is proposed in this paper. Through the push-out test, the interface shear behavior of the new stud shear connector between steel and concrete flange plate was studied, and the difference between the new stud shear connector and the traditional stud connector was compared. The results show that the stud shear connector with constraint measure can effectively avoid the adverse effect of local pressure splitting by relying on its own constraint measure. The shear stiffness of the interface between steel and concrete flange plates is greatly improved, which provides a theoretical basis for the design of strong connection coefficient of steel-concrete composite structures.

Comparison of the safety between cervical conization and hysterectomy for patients with cervical adenocarcinoma in situ

Jingjing Liu,Yu Wang,Xiaoyun Wan,Jian Zou,Yedan Zhu,Weiguo Lv,Yuanming Shen 대한부인종양학회 2023 Journal of Gynecologic Oncology Vol.34 No.1

Objective: To compare the safety between cervical conization (CC) alone and hysterectomy for patients with adenocarcinoma in situ (AIS) of the cervix. Methods: Patients diagnosed with AIS after CC during 2007–2021 were identified by computerized databases at Women’s Hospital of Zhejiang University School of Medicine. A total of 453 AIS patients were divided into 2 groups according to uterus preservation: hysterectomy group (n=300) and CC(s) alone group (n=153). The prevalence of residual disease and disease recurrence was compared between patients treated by CC(s) alone and hysterectomy. The prevalence of residual disease in specimens from women who had a hysterectomy and repeat CC were compared between positive and negative margins of CC. The factors influencing residual disease and disease recurrence were assessed. Results: Among 310 specimens from women who had a hysterectomy or repeat CC, the prevalence of residual disease was 50.6% (45/89) for a positive margin and 2.3% (5/221) for a negative margin (p=0.000). Four patients had recurrence of vaginal intraepithelial neoplasia in those treated by hysterectomy and one had recurrence of cervical squamous intraepithelial neoplasia in those treated by CC(s) alone. The prevalence of recurrence was 0.7% (1/153) for CC(s) alone and 1.3% (4/300) for hysterectomy (p=0.431). Hysterectomy did not influence residual disease or disease recurrence. Conclusion: CC is an efficacious and safe option for patients with AIS of the cervix provided the margin is negative.

Mechanical Property and Microstructure of Fly Ash-Based Geopolymer Activated by Sodium Silicate

Qingfeng Lv,Jingjing Yu,Fengling Ji,Liuyang Gu,Yi Chen,Xiaokang Shan 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.5

Sodium silicate is one of the common alkali activators of geopolymers. The modulus, concentration and dosage of sodium silicate have significant effects on the activation of fly ash, the strength and microstructure of geopolymer. In this paper, unconfined compressive strength test, X-ray diffraction analysis (XRD), Fourier transform infrared light (FTIR), 29Si nuclear magnetic resonance (29Si NMR), scanning electron microscope and energy disperse spectroscopy (SEM-EDS), and physisorption experiment (BET) were carried out to study the effects of the sodium silicate modulus and dosage on the mechanical property and microstructure of fly ash-based geopolymer. The results indicated that the main product of the geopolymer activated by sodium silicate was hydrated sodium aluminosilicate (N-A-S-H). When modulus value decreased and meanwhile dosage of sodium silicate increased, the reorganization and polymerization of gel products were accelerated so that the integrity and continuity of the microstructure of geopolymer were improved, and then the strength increased. When the modulus of sodium silicate was 3.28, the maximum value of the strength was at the dosage of 10%. According to this study, it was investigated that modulus value and dosage of sodium silicate had obvious influence on the alkali- activated reaction of fly ash, which can provide an engineering reference for the special soil solidification with geopolymers.

Long-term Survivals, Toxicities and the Role of Chemotherapy in Early-Stage Nasopharyngeal Carcinoma Patients Treated with Intensity-modulated Radiation Therapy: A Retrospective Study with 15-year Follow-up

Lin Wang,Jingjing Miao,Huageng Huang,Boyu Chen,Xiao Xiao,Manyi Zhu,Yingshan Liang,Weiwei Xiao,Shaomin Huang,Yinglin Peng,Xiaowu Deng,Xing Lv,Weixiong Xia,Yanqun Xiang,Xiang Guo,Fei Han,Chong Zhao 대한암학회 2022 Cancer Research and Treatment Vol.54 No.1

Purpose This study was aimed to investigate long-term survivals and toxicities of early-stage nasopharyngeal carcinoma (NPC) in endemic area, evaluating the role of chemotherapy in stage II patients. Materials and Methods Totally 187 patients with newly diagnosed NPC and restaged American Joint Committee on Cancer/ International Union Against Cancer 8th T1-2N0-1M0 were retrospectively recruited. All received intensity-modulated radiotherapy (IMRT)±chemotherapy (CT) from 2001 to 2010. Results With 15.7-year median follow-up, 10-year locoregional recurrence-free survival, distant metastasis-free survival (DMFS), disease-specific survival (DSS), and overall survival (OS) were 93.3%, 93.5%, 92.9% and 88.2%, respectively. Multivariable analyses showed cervical lymph nodes positive and pre-treatment prognostic nutritional index ≥ 52.0 could independently predict DMFS (p=0.036 and p=0.011), DSS (p=0.014 and p=0.026), and OS (p=0.002 and p < 0.001); Charlson comorbidity index < 3 points could predict DSS (p=0.011); age > 45 years (p=0.002) and pre-treatment lactate dehydrogenase ≥ 240 U/L (p < 0.001) predicted OS. No grade 4 late toxicity happened; grade 3 late toxicities included subcutaneous fibrosis (4.3%), deafness or otitis (4.8%), skin dystrophy (2.1%), and xerostomia (1.1%). No differences on survivals were shown between IMRT+CT vs. IMRT alone in stage II patients, even in T2N1M0 (p > 0.05). Unsurprising, patients in IMRT+CT had more acute gastrointestinal reaction, myelosuppression, mucositis, late ear toxicity, and cranial nerve injury (all p < 0.05) than IMRT alone group. Conclusion Superior tumor control and satisfying long-term outcomes could be achieved with IMRT in early-stage NPC with mild late toxicities. As CT would bring more toxicities, it should be carefully performed to stage II patients.

Lotus-Like Nano-Architectures Constructed from Self-Assembled Micelles via Hierarchical Assembly

Rongli Zhang,Xiaoxia Fan,Xiaofang Xu,Jingjing Lv,Zhenzhen Jin,Hui Hao,Cuige Zhang 한국고분자학회 2018 Macromolecular Research Vol.26 No.1

Dopamine modified γ-polyglutamic acid (γ-PGA-DA) copolymer and melamine (Mel) can self-assemble into Mel/γ-PGA-DA micelles via weak intermolecular interactions in aqueous solution containing small amount of methanol. When Mel/γ-PGA-DA micellar solution was cast on the surface of formvar stabilized with carbon support films, the lotus-like nano-architectures were formed on the surface of substrate via hierarchical assembly of micelles. The size of lotus-like nanoarchitectures was approximately 200 nm×500 nm. The possible driving forces for hierarchical assembly of micelles were the solution fluid and interaction between micelles. The hierarchical assembly of micelles was similar to the fractal aggregation of inorganic particles and a possible reason was discussed.

Hollow Silicon Oxide Sphere Coated with Cuprous Oxide and Polyaniline as an Anode for High-Performance Lithium-Ion Batteries

Meiqiang Fan,Yong Jin Zou,Hao Yin,Yan Li Huang,Chengqiao Xi,Haixin Kang,Chao Li,Jingjing Zhang,Chunju Lv,Meiqiang Fan,Zhi Chen 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.3

A hollow silicon oxide coated with cuprous oxide and polyaniline (hSiOx/Cu2O/PANI) was prepared via Stober method, magnesium reduction and chemical oxidative polymerization. The hSiOx/Cu2O/PANI (SiOx 62 wt.%, PANI 33 wt.%, Cu2O 5 wt.%) presented charge/discharge capacities of up to 2000 mAhg -1 after 60 cycles at 0.2 Ag -1 current density and higher than 880 mAhg -1 at 8 Ag -1 current density. Microstructural analysis demonstrated that the improvement was due to the nanostructure of hollow SiOx sphere coated with Cu2O and PANI, which could release high stress caused by volume expansion during the lithiation/delithiation process and had little damage to electrode materials. Cycle voltammetry (CV) and electrochemical impedance spectroscopy (EIS) results further confirmed that Cu2O and PANI dual-coating improved reversibility and conductivity of hSiOx and prevented it to drop from the electrode surface.