24 research outputs found

    Recent Advances in Precision Diamond Wire Sawing Monocrystalline Silicon

    No full text
    Due to the brittleness of silicon, the use of a diamond wire to cut silicon wafers is a critical stage in solar cell manufacturing. In order to improve the production yield of the cutting process, it is necessary to have a thorough understanding of the phenomena relating to the cutting parameters. This research reviews and summarizes the technology for the precision machining of monocrystalline silicon using diamond wire sawing (DWS). Firstly, mathematical models, molecular dynamics (MD), the finite element method (FEM), and other methods used for studying the principle of DWS are compared. Secondly, the equipment used for DWS is reviewed, the influences of the direction and magnitude of the cutting force on the material removal rate (MRR) are analyzed, and the improvement of silicon wafer surface quality through optimizing process parameters is summarized. Thirdly, the principles and processing performances of three assisted machining methods, namely ultrasonic vibration-assisted DWS (UV-DWS), electrical discharge vibration-assisted DWS (ED-DWS), and electrochemical-assisted DWS (EC-DWS), are reviewed separately. Finally, the prospects for the precision machining of monocrystalline silicon using DWS are provided, highlighting its significant potential for future development and improvement

    The Effect of Tree-Planting Patterns on the Microclimate within a Courtyard

    No full text
    Current landscape design within a courtyard usually does not take into account the influence of the tree-planting pattern, which has an important influence on the outdoor microclimate and occupants’ thermal comfort. At present, the extent of the influence on the microclimate has not yet been made clear. Computational Fluid Dynamics (CFD) was employed to run this model under hot summer weather conditions. Field measurements validated the performance of the CFD model. This study conducted numerical simulations for five different tree-planting patterns, including (i) focused tree-planting (F), (ii) cornered tree-planting (C), (iii) multi-row tree-planting (R), (iv) surround tree-planting (S) and (v) no tree-planting (N). Our study found that the tree-planting pattern affects both the distribution of air temperature and the degree of local heat transfer. Specifically, the C, S and N patterns allow for higher ventilation in the studied courtyard, while the F and R patterns cause lower wind velocities and associated courtyard ventilation. The average air temperature for the C pattern is lower during summer afternoons than the other patterns. The wind flow pattern in the studied courtyard does not vary significantly with different tree-planting patterns. Nevertheless, the general relative humidity in the courtyard does not vary significantly with different tree-planting patterns, except for the N pattern. A future analysis is needed to investigate the mechanisms of the phenomenon

    Nab-Paclitaxel in combination with Cisplatin Versus Docetaxel Plus Cisplatin as First-Line Therapy in Non-small Cell Lung Cancer

    No full text
    Abstract Albumin-bound paclitaxel (nab-PC) and docetaxel both produced favorable efficacy and safety as first-line therapy in advanced non-small cell lung cancer (NSCLC). However, the comparison between nab-PC and docetaxel remained unclear until now. This retrospective study aimed to compare the efficacy and safety of nab-PC/cisplatin with docetaxel/cisplatin as first-line therapy in advanced NSCLC. 271 patients with advanced NSCLC, who received either nab-PC (55 patients) or docetaxel (216 patients) were reviewed from 2012 to 2016. The primary endpoint was objective overall response rate (ORR). The secondary endpoints were disease control rate (DCR), progression-free survival (PFS), overall survival (OS) and safety profiles. Nab-PC presented a significantly higher ORR than docetaxel (47.3% vs 31.9%; P = 0.033). The difference of ORR was more significantly remarkable in patients with squamous histology (58.3% vs 29.0%; P = 0.007). Additionally, the DCR of nab-PC was significantly higher than docetaxel. Patients in nab-PC group had a trend toward improved PFS and OS compared with patients in docetaxel group, but this didn’t reach statistical significance. Grade ≥ 3 neutropenia was less in nab-PC group, while Grade ≥ 3 anemia and thrombocytopenia were less in docetaxel group. Nab-PC/cisplatin as first-line therapy, produced significantly higher efficacy and reduced neutropenia than docetaxel/cisplatin in advanced NSCLC

    Optimization of process parameters and performance for machining Inconel 718 in renewable dielectrics

    No full text
    In this study, the optimization of processing parameters of Inconel 718 using electrical discharge machining (EDM) with three kinds of renewable dielectrics (soybean oil, sunflower seed oil, and rapeseed oil) was studied. As input process parameters, pulse current, pulse duration, duty ratio, and dielectric type were all utilized. The machining performance indices of EDM were material removal rate (MRR), surface roughness (Ra), energy pulse ratio per volume (EEV), and exhaust emission characteristics (EEC). The response surface method (RSM) was used to carry out the central composite design of the EDM experiment, and it looked into how process parameters affected machining performance. In addition, the extreme learning machine (ELM)-improved integrated beta-distribution cuckoo search (IBCS) algorithm was used to optimize the EDM process, and the optimization results were verified by experiments. The research results demonstrate that the predicted results are generally better than the experimental results, and the maximum and average deviations of the experimental results are within the acceptable range (maximum deviation <20%, average deviation <15%). The effectiveness of the optimization algorithm was proved, which was helpful in improving the performance of EDM, reducing energy consumption and emissions, and improving the sustainability of EDM

    Pretreatment lactate dehydrogenase may predict outcome of advanced non small‐cell lung cancer patients treated with immune checkpoint inhibitors: A meta‐analysis

    No full text
    Abstract The main aim of this study is to investigate whether baseline lactate dehydrogenase (LDH) is associated with the clinical outcome of non small‐cell lung cancer (NSCLC) patients treated with immune checkpoint inhibitors (ICIs). We searched Pubmed, the Cochrane Central library and Embase for peripheral blood biomarker of LDH in advanced NSCLC patients treated with ICIs. We extracted the hazard ratio (HR) with 95% confidence interval (CI) for the progression free survival (PFS) and overall survival (OS) and performed meta‐analysis of HR. Pooled estimates of treatment outcomes were calculated by stata 15.1. Six studies with 1136 patients were included in this study. The pooled results of univariate analysis suggested that an elevated pretreatment LDH level was correlated with significant shorter PFS (HR = 1.53, 95% CI 1.27‐1.83, P < 0.001) and OS (HR = 2.11, 95% CI 1.43‐3.11, P < 0.001). The association remained significant in the multivariate analysis that elevated pretreatment LDH level was associated with poor PFS (HR = 1.62, 95% CI 1.26‐2.08, P < 0.001) and OS (HR = 2.38, 95% CI 1.37‐4.12, P = 0.002). A high pretreatment LDH level was significantly correlated with shorter PFS and OS. Pretreatment LDH may serve as a predictive biomarker for advanced NSCLC patients treated with ICIs

    Efficacy and Toxicity of Pemetrexed or Gemcitabine Combined with Cisplatin in the Treatment of Patients with Advanced Non-small Cell Lung Cancer

    No full text
    Background and objective Due to the various inter-individual differences in the biological characteristics of tumor cells, as well as issues on the efficacy, adverse reactions, and defects of existing drugs, we compared the clinical efficacy and toxicity of pemetrexed and gemcitabine combined with cisplatin for the treatment of previously untreated advanced non-small cell lung cancer (NSCLC). Methods 251 patients were randomly divided into pemetrexed combined with cisplatin group (PP group) with 127 cases and gemcitabine combined with cisplatin group (GP group) with 124 cases. PP group received pemetrexed 500 mg/m2 iv infusion d1 and cisplatin 75 mg/m2 iv infusion d1, whereas GP group received gemcitabine 1,000 mg/m2 iv infusion d1,8 and cisplatin 75 mg/m2 iv infusion d1. The treatment cycle was once every three weeks. In addition, folic acid, vitamin B12, and dexamethasone were administered in both groups. Results The total clinical effective rates in PP group and GP group were 25.20% and 17.74%, respectively. The total efficiencies of non-squamous cell carcinoma were 27.62% and 16.00%. The tumor progression duration in these two groups was 6.5 and 5.6 months, respectively. The median survival time in the two groups was 16.9 and 17.0 months, respectively, with 59.62% and 65.87% survival rates of 1 year and 27.28% and 27.93% survival rates of 2 years, respectively. The total efficacy of non-squamous cell carcinoma in the PP group was significantly higher than that in GP group. The results were statistically significant. However, there were no significant differences in total response rates, tumor progression duration, and median survival rates of 1 and 2 years. The rate of adverse reactions, including white blood cell reduction, lower platelet count, lower hemoglobin, and hair loss in the PP group was significantly lower than that in the GP group. The results were statistically significant. Conclusion The clinical efficacy of pemetrexed and gemcitabine combined with cisplatin for the treatment of previously untreated advanced NSCLC was roughly the same, but the adverse reactions decreased significantly in the PP group compared with those in the GP group. Therefore, pemetrexed combined with cisplatin can be used as a safe and effective drug for clinical first-line treatment for previously untreated NSCLC

    Comprehensive analysis of age‐related somatic mutation profiles in Chinese young lung adenocarcinoma patients

    No full text
    Abstract Background Lung adenocarcinoma in young adults is a rare entity with the oncogenic genetic alterations associated being poorly understood. In the present study, the effect of genetic alterations in lung adenocarcinoma patients diagnosed in young patients is reported. Methods Twenty young lung adenocarcinoma patients (age years: median: 33.5, range: 24‐36) were enrolled in the current study and 24 patients who were at common age of the disease onset (age years: median: 61.5, range: 52‐79) were selected for comparison. Paraffin sections of lung adenocarcinoma were analyzed using the whole‐exome sequencing platform. Results Similar number of somatic mutations per tumor were found in the young patients and their older counterparts. Although no age‐related differences were detected in the numbers of lung adenocarcinoma patients harboring well‐known gene variants, mutations in FRG1 and KMT2C were associated with a younger age especially after correcting for tobacco smoking and sex (FRG1: P = 0.027, KMT2C: P = 0.046). Five genetic variants showed higher alteration frequencies in young patients compared to the unclassified East Asian population, suggesting these mutations as disease‐related hereditary germline variants. Conclusions These results suggest different characteristics of lung adenocarcinoma between the young and the patients at common age of onset. Young patients with lung adenocarcinoma have a distinctly unique prevalence of oncogenic genetic alterations

    Structure of Amorphous Selenium: Small Ring, Big Controversy

    No full text
    Selenium (Se) discovered in 1817 belongs to the family of chalcogens. Surprisingly, despite the long history of over two centuries and the chemical simplicity of Se, the structure of amorphous Se (a-Se) remains controversial to date regarding the dominance of chains versus rings. Here, we find that vapor-deposited a-Se is composed of disordered rings rather than chains in melt-quenched a-Se. We further reveal that the main origin of this controversy is the facile transition of rings to chains arising from the inherent instability of rings. This transition can be inadvertently triggered by certain characterization techniques themselves containing above-bandgap illumination (above 2.1 eV) or heating (above 50 °C). We finally build a roadmap for obtaining accurate Raman spectra by using above-bandgap excitation lasers with low photon flux (below 1017 phs m–2 s–1) and below-bandgap excitation lasers measured at low temperatures (below −40 °C) to minimize the photoexcitation- and heat-induced ring-to-chain transitions
    corecore