28 research outputs found
The synergetic effects of surface texturing and MoDDP additive applied to ball-on-disk friction subject to both flooded and starved lubrication conditions
This paper reports a novel work on the synergetic effects of microscale surface texturing and lubricant friction modifier additive of molybdenum dialkyldithiophosphate (MoDDP) subject to both flooded and starved lubrication conditions. The experiments were performed on reciprocating ball-on-disk friction in GTL8 base oil with and without MoDDP. In the flooded lubrication condition, the test results demonstrated that the presence of the MoDDP additive contributed to lower friction coefficients, and also more pronounced effect of surface textures on friction than in the case of the bare base oil. In the starved lubrication experiments, textured and texture-free surfaces in the oils with and without MoDDP additive were tested until an abrupt rising of friction coefficient was detected. The results showed that the magnitude of friction coefficient before terminating each test was the almost same for various tests, while the endurance time in different test conditions was significantly different. The textured surface exhibited longer endurance time than the texture-free surface, especially when the MoDDP additive was used. The mechanism of the synergetic effects of surface textures and MoDDP additive has been discussed based on the experimental observations in the following sections. This study provides a new idea for the application of surface texture in boundary lubrication when lubricant additive is contained in the lubricating oils
A Revised Method of Surface Water Quality Evaluation Based on Background Values and Its Application to Samples Collected in Heilongjiang Province, China
In China, the use of certain standards to evaluate surface water quality in areas with high background values due to natural factors rather than to human activities results in water quality underestimation and thus affects regional water quality management and decision-making. Herein, we examined river source water function zones of the Heilongjang province characterised by high background values and analysed the corresponding water quality data acquired in 2011−2016. The examined samples featured elevated chemical oxygen demand (COD), permanganate index (CODMn), and ammonia nitrogen (NH3-N) levels, which indicated that water quality was affected by the natural environment. The concentrations of background pollutants almost exceeded the limits stipulated by regional surface water quality standards and exhibited strong spatiotemporal variability. A three-step discrimination method including single index recognition, limiting factors, and a synthetic index was proposed to distinguish the background area among these zones for determining background values, and 10 complete background areas were identified. The background values of COD, CODMn, and NH3-N for the entire area were determined based on the data acquired during background area monitoring. Finally, considering the present procedure of water quality evaluation in China (single factor exponential method), a revised method based on background values was suggested. Thus, the evaluation results objectively and accurately reflect the regional water quality situation and therefore provide a scientific basis for the development of a better water quality assessment and management system in China
Low-frequency noise properties in Pt-indium gallium zinc oxide Schottky diodes
The low-frequency noise properties of Pt-indium gallium zinc oxide (IGZO) Schottky diodes at different forward biases are investigated. The IGZO layer and Pt contact were deposited by RF sputtering at room temperature. The diode showed an ideality factor of 1.2 and a barrier height of 0.94 eV. The current noise spectral density exhibited 1/f behavior at low frequencies. The analysis of the current dependency of the noise spectral density revealed that for the as-deposited diode, the noise followed Luo's mobility and diffusivity fluctuation model in the thermionic-emission-limited region and Hooge's empirical theory in the series-resistance-limited region. A low Hooge's constant of 1.4 × 10−9 was found in the space-charge region. In the series-resistance-limited region, the Hooge's constant was 2.2 × 10−5. After annealing, the diode showed degradation in the electrical performance. The interface-trap-induced noise dominated the noise spectrum. By using the random walk model, the interface-trap density was obtained to be 3.6 × 1015 eV−1 cm−2. This work provides a quantitative approach to analyze the properties of Pt-IGZO interfacial layers. These low noise properties are a prerequisite to the use of IGZO Schottky diodes in switch elements in memory devices, photosensors, and mixer diodes
Do women with high-risk HPV E6/E7 mRNA test positivity and NILM cytology need colposcopy?
Abstract Purpose This study aimed to assess the value of an HPV E6/E7 mRNA assay and HPV 16 18/45 genotype assay combined with age stratification for triaging women negative for intraepithelial lesions or malignancy (NILM) cytology. Methods From January 2017 to December 2021, a total of 162,309 eligible women underwent cervical cancer screening at the Affiliated Hospital of Jining Medical University, China. Excluding those with negative HPV E6/E7 mRNA, abnormal and unsatisfactory cytology, and those who failed to undergo colposcopy, 6,845 women were ultimately included in our study. We analysed the triage guidance for different subtypes of HPV in the presence of NILM cytology. Results Among 162,309 women, 19,834 (12.2%) were positive for HPV E6/E7 mRNA. Of the 6,845 women included in the study, 1,941 (28.4%), 561 (8.2%), 55 (0.8%) and 4,288 (62.6%) tested positive for HPV 16, HPV 18/45, HPV16/18/45 or other HR-HPV genotypes, respectively. The proportions of LSIL+ (including LSIL, HSIL and ICC) and HSIL+ (including HSIL and ICC) pathological results in the HPV 16/18/45 + group were 57% and 34.1%, respectively, higher than 36.3% and 11% in the other HR-HPV + group (χ2 = 653.214, P  0.05). The above results were consistent after stratification according to age. Conclusion The rate of histopathological abnormalities was still high for the other HR-HPV subtypes with NILM cytology, although the rate of histopathological abnormalities was much higher for the HPV 16/18/45 positive subtypes. Therefore, colposcopy should be performed in women with HPV E6/E7 mRNA positivity and NILM cytology, regardless of age and HPV genotype
A new algorithm of dangerous points accurately identification on mechanical structure under dynamic loads
A Revised Method of Surface Water Quality Evaluation Based on Background Values and Its Application to Samples Collected in Heilongjiang Province, China
Association between Genetic Polymorphisms in Interleukin Genes and Recurrent Pregnancy Loss – A Systematic Review and Meta-Analysis
<div><p>Interleukins are a group of immunomodulatory proteins that mediate a variety of immune reactions in the human body. To investigate the association between interleukin gene polymorphisms and recurrent pregnancy loss (RPL), we reviewed 21 studies from MEDLINE, EMBASE, OVID SP and PubMed to evaluate RPL-related interleukin gene polymorphisms. Meta-analysis was performed on 12 of the polymorphisms, and a review included the others. Our integrated results indicated that IL-1β (-511C/T) (P = 0.02, 95% CI 0.77[0.62,0.96]), IL-6 (-634C/G) (P<0.001, 95% CI 2.91[2.01,4.22]), IL-10 (-1082G/A, –819T/C) (P = 0.01, 95% CI 0.80[0.67,0.96]; P<0.01, 95% CI 0.66[0.49,0.89]), and IL-18 (-137G/C, -105G/A) (P<0.01, 95% CI 1.69[1.24,2.31]; P = <0.01, 95% CI 1.41[1.17,1.70]) consistently associated with RPL after meta-analysis. IL-17A rs2275913 and IL-17F rs763780, IL-21 rs2055979 and rs13143866, IL-1β (-31C/T), IL-6 (-2954G/C), and IL-10 (-536A/G) were reported only once as having a significant association with RPL. The potential mechanism underlying miscarriage and these polymorphisms and future research directions are also discussed.</p></div
Reliability of using vegetation optical depth for estimating decadal and interannual carbon dynamics
Vegetation optical depth (VOD) from satellite passive microwave sensors has enabled monitoring of aboveground biomass carbon dynamics by building a relationship with static carbon maps over space and then applying this relationship to VOD time series. However, uncertainty in this relationship arises from changes in water stress, as VOD is mainly determined by vegetation water content, which varies at diurnal to interannual scales, and depends on changes in both biomass and relative moisture content. Here, we studied the reliability of using VOD from various microwave frequencies and temporal aggregation methods for estimating decadal biomass carbon dynamics at the global scale. We used the VOD diurnal variations to represent the magnitude of vegetation water content buffering caused by climatic variations for a constant amount of dry biomass carbon. This magnitude of VOD diurnal variations was then used to evaluate the likelihood of VOD decadal variations in reflecting decadal dry biomass carbon changes. We found that SMOS-IC L-VOD and LPDR X-VOD can be reliably used to estimate decadal carbon dynamics for 76.7% and 69.9% of the global vegetated land surface, respectively, yet cautious use is warranted for some areas such as the eastern Amazon rainforest. Moreover, the annual VOD aggregated from the 95% percentile of the nighttime VOD retrievals was proved to be the most suitable parameter for estimating decadal biomass carbon dynamics among the temporal aggregation methods. Finally, we validated the use of annual VOD for estimating interannual carbon dynamics by comparing VOD changes between adjacent years against eddy covariance estimations of gross primary production from flux sites over several land cover classes across the globe. Despite the large difference in spatial scales between them, the positive correlation obtained supports the capability of satellite VOD in quantifying interannual carbon dynamics