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An electron in liquid helium forces open a cavity referred as an electron bubble. These objects have been studied in many past experiments. It has been discovered that under certain conditions other negatively charged objects can ...
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An electron in liquid helium forces open a cavity referred as an electron bubble. These objects have been studied in many past experiments. It has been discovered that under certain conditions other negatively charged objects can be produced but the nature of these “exotic ions” is not understood. We have made a series of experiments to measure the mobility of these objects, and have detected at least 18 ions with different mobility. We also find strong evidence that in addition to these objects there are ions present which have a continuous distribution of mobility. We then describe experiments in which we attempt to produce exotic ions by optically exciting an electron bubble to a higher energy quantum state. To within the sensitivity of the experiment, we have not been able to detect any exotic ions produced as a result of this process. We discuss three possible explanations for the exotic ions, namely impurities, negative helium ions, and fission of the electron wave function. Each of these explanations has difficulties but as far as we can see, of the three, fission is the only plausible explanation of the results which have been obtained.
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The Pixel Luminosity Telescope is a silicon pixel detector dedicated to luminosity measurement at the CMS experiment at the LHC. It is located approximately 1.75 m from the interaction point and arranged into 16 “telescopes”, wi...
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The Pixel Luminosity Telescope is a silicon pixel detector dedicated to luminosity measurement at the CMS experiment at the LHC. It is located approximately 1.75 m from the interaction point and arranged into 16 “telescopes”, with eight telescopes installed around the beam pipe at either end of the detector and each telescope composed of three individual silicon sensor planes. The per-bunch instantaneous luminosity is measured by counting events where all three planes in the telescope register a hit, using a special readout at the full LHC bunch-crossing rate of 40 MHz. The full pixel information is read out at a lower rate and can be used to determine calibrations, corrections, and systematic uncertainties for the online and offline measurements. This paper details the commissioning, operational history, and performance of the detector during Run?2 (2015–18) of the LHC, as well as preparations for Run 3, which will begin in 2022.
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For Zn-anode rechargeable batteries, there are a number of shortcomings associated with using traditional KOH aqueous electrolytes. These include drying-out of the electrolyte due to water evaporation and dendrite formation at the...
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For Zn-anode rechargeable batteries, there are a number of shortcomings associated with using traditional KOH aqueous electrolytes. These include drying-out of the electrolyte due to water evaporation and dendrite formation at the anode, which severely impair battery performance (e.g., cycle life and capacity) and limit their application. It is, therefore, critical to either modify conventional KOH aqueous electrolytes or explore alternative electrolytes to eliminate these bottlenecks to the development of a feasible Zn-anode rechargeable battery system. Room temperature ionic liquids (RTILs) in recent years have been increasingly recognized as potential electrolytes or electrolyte components for rechargeable batteries. Compared with alkaline electrolytes, a simple electrolyte system composed of an RTIL as the sole component faces the challenge of improving its low conductivity before it can be practically applied in a battery. In this chapter, water and/or dimethyl sulfoxide modified RTILs (composed of pyrrolidinium or imidazolium cations and bis(trifluoromethanesulfonyl)imide or dicyanamide anions), with improved conductivity and Zn redox kinetics, are investigated as potential electrolyte systems for Zn-anode rechargeable batteries. In addition, with the capability of modifying metal deposit morphology, RTILs are found to be beneficial for depressing Zn dendrite formation in KOH aqueous electrolytes. An electrolyte, composed of 9M KOH + 5 wt% ZnO with a hydrophilic RTIL (0.5 wt% 1-ethyl-3-methylimidazolium dicyanamide), appears to be a promising electrolyte system for Zn-anode rechargeable batteries.
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Recent changes in the Earth's climate have led to renewed interest in extreme cold wave (ECW) events. This study identifies the ECW patterns over the Chinese mainland, their corresponding large-scale meteorological patterns (LMPs)...
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Recent changes in the Earth's climate have led to renewed interest in extreme cold wave (ECW) events. This study identifies the ECW patterns over the Chinese mainland, their corresponding large-scale meteorological patterns (LMPs) and their favorable planetary wave patterns over 1961-2015. A self-organizing map classifies ECWs into northeast, nationwide, northwest-south and Qinghai- Tibetan Plateau clusters. The cold anomalies are primarily contributed by the anomalous wind advecting climatological mean temperature for the leading three clusters, but diabaitic heating for the Qinghai- Tibetan Plateau cluster. The associated LMPs are primarily characterized by a dipole with a positive height anomaly over Siberia and a negative height anomaly extending from Japan to the Iranian Plateau, which displaces southwestward among the four ECW clusters. The LMPs induce anomalous northerly flows extending from the upper troposphere to the near-surface, which deepen the negative height anomaly southwestward from the East Asian trough and accumulate cold air masses over the key regions within the dipole that are phase-locked with the LMPs (i.e., baroclinic growth). Such baroclinic growth of the LMP is larger during periods of a planetary wave (wavenumbers 1-5) resembling the Northern Annular Mode (NAM). Meanwhile, the negative (positive) phase of the NAM provides more direct contribution to the LMP of the northeast and nationwide (Qinghai-Tibetan Plateau) ECW clusters and thus are likely to favor the occurrence of ECWs. The negative phase of NAM-like planetary waves exhibit a positive trend after the transition year of 1987, and could potentially increase the occurrence frequency of nationwide ECWs.
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This paper is focused on an analytical model to simulate the damage propagation behavior and to predict the onset of damage propagation of a low-velocity impacted composite sandwich panel subjected to increasing uniaxial compressi...
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This paper is focused on an analytical model to simulate the damage propagation behavior and to predict the onset of damage propagation of a low-velocity impacted composite sandwich panel subjected to increasing uniaxial compressive load. Major damage modes due to impact, such as the residual indentation and the locally crushed core, are included into this model. Composite sandwich panels with unsymmetrical angle-plied facesheets are studied. A consequential core-crushing mechanism is incorporated into the analysis. Good correlations between the numerical results and the experimental data have been obtained. The far-field stress corresponding to the onset of damage propagation at a characteristic location near the damage zone has been captured accurately. This quantity can be used to represent the residual load-bearing capacity of an impact-damaged sandwich panel under compression. It serves as a characteristic value in a newly proposed event-driven failure criterion named damage propagation criterion. This criterion can be used in both the damage tolerant design and the safety evaluation of composite sandwich structures.
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There always exist parametric uncertainties, bounded disturbances and some other unknown nonlinearities such as the input dead-zone in physical motor servo systems, which can degrade the system's control performance. In this paper...
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There always exist parametric uncertainties, bounded disturbances and some other unknown nonlinearities such as the input dead-zone in physical motor servo systems, which can degrade the system's control performance. In this paper, a composite control strategy is proposed for high-accuracy motion control of a torque-controlled motor servo system with dead-zone. A smooth and continuous mathematical model is used to provide an approximate inverse transformation of the input-output dead-zone needed for feedback linearization. A single-layer neural network capable of on-line learning is designed to compensate for the inversion error, which comes from the approximate inversion. A stable weights adaption law for the on-line neural network is derived. In addition, a parameter adaptation law is also derived for handling the parametric uncertainty, and a nonlinear robust feedback term is designed to inhibit the influence of the imperfect modeling, compensation error or other disturbances. Lyapunov theorem is used to prove the stability of the proposed control algorithm with the weights and parameters adaptation law. Extensive comparative simulation results are used to illustrate the effectiveness and advancement of the proposed controller compared with several other main-stream controllers.
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Mitis-group streptococci are ubiquitous oral commensals that can promote polybacterial biofilm virulence. Using a novel murine oral mucosal co-infection model we sought to determine for the first time whether these organisms promo...
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Mitis-group streptococci are ubiquitous oral commensals that can promote polybacterial biofilm virulence. Using a novel murine oral mucosal co-infection model we sought to determine for the first time whether these organisms promote the virulence of C.?albicans mucosal biofilms in oropharyngeal infection and explored mechanisms of pathogenic synergy. We found that Streptococcus oralis colonization of the oral and gastrointestinal tract was augmented in the presence of C.?albicans. S.?oralis and C.?albicans co-infection significantly augmented the frequency and size of oral thrush lesions. Importantly, S.?oralis promoted deep organ dissemination of C.?albicans. Whole mouse genome tongue microarray analysis showed that when compared with animals infected with one organism, the doubly infected animals had genes in the major categories of neutrophilic response/chemotaxis/inflammation significantly upregulated, indicative of an exaggerated inflammatory response. This response was dependent on TLR2 signalling since oral lesions, transcription of pro-inflammatory genes and neutrophil infiltration, were attenuated in TLR2 ?/? animals. Furthermore, S.?oralis activated neutrophils in a TLR2-dependent manner in vitro. In summary, this study identifies a previously unrecognized pathogenic synergy between oral commensal bacteriaand C.?albicans. This is the first report of the ability of mucosal commensal bacteria to modify the virulence of an opportunistic fungal pathogen.
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Mitis-group streptococci are ubiquitous oral commensals that can promote polybacterial biofilm virulence. Using a novel murine oral mucosal co-infection model we sought to determine for the first time whether these organisms promo...
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Mitis-group streptococci are ubiquitous oral commensals that can promote polybacterial biofilm virulence. Using a novel murine oral mucosal co-infection model we sought to determine for the first time whether these organisms promote the virulence of C. albicans mucosal biofilms in oropharyngeal infection and explored mechanisms of pathogenic synergy. We found that Streptococcus oralis colonization of the oral and gastrointestinal tract was augmented in the presence of C. albicans. S. oralis and C. albicans co-infection significantly augmented the frequency and size of oral thrush lesions. Importantly, S. oralis promoted deep organ dissemination of C. albicans. Whole mouse genome tongue microarray analysis showed that when compared with animals infected with one organism, the doubly infected animals had genes in the major categories of neutrophilic response/chemotaxis/inflammation significantly upregulated, indicative of an exaggerated inflammatory response. This response was dependent on TLR2 signalling since oral lesions, transcription of pro-inflammatory genes and neutrophil infiltration, were attenuated in TLR2~(-/-) animals. Furthermore, S. oralis activated neutrophils in a TLR2-dependent manner in vitro. In summary, this study identifies a previously unrecognized pathogenic synergy between oral commensal bacteria and C. albicans. This is the first report of the ability of mucosal commensal bacteria to modify the virulence of an opportunistic fungal pathogen.
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BACKGROUND:Patients with cancer may be at high risk of adverse outcomes from SARS-CoV-2 infection. We analyzed a cohort of patients with cancer and COVID-19 reported to the COVID-19 and Cancer Consortium (CCC19) to identify progno...
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BACKGROUND:Patients with cancer may be at high risk of adverse outcomes from SARS-CoV-2 infection. We analyzed a cohort of patients with cancer and COVID-19 reported to the COVID-19 and Cancer Consortium (CCC19) to identify prognostic clinical factors, including laboratory measurements and anti-cancer therapies.PATIENTS AND METHODS:Patients with active or historical cancer and a laboratory-confirmed SARS-CoV-2 diagnosis recorded between March 17-November 18, 2020 were included. The primary outcome was COVID-19 severity measured on an ordinal scale (uncomplicated, hospitalized, admitted to intensive care unit, mechanically ventilated, died within 30 days). Multivariable regression models included demographics, cancer status, anti-cancer therapy and timing, COVID-19-directed therapies, and laboratory measurements (among hospitalized patients).RESULTS:4,966 patients were included (median age 66 years, 51% female, 50% non-Hispanic white); 2,872 (58%) were hospitalized and 695 (14%) died; 61% had cancer that was present, diagnosed, or treated within the year prior to COVID-19 diagnosis. Older age, male sex, obesity, cardiovascular and pulmonary comorbidities, renal disease, diabetes mellitus, non-Hispanic Black race, Hispanic ethnicity, worse ECOG performance status, recent cytotoxic chemotherapy, and hematologic malignancy were associated with higher COVID-19 severity. Among hospitalized patients, low or high absolute lymphocyte count, high absolute neutrophil count, low platelet count, abnormal creatinine, troponin, LDH, and CRP were associated with higher COVID-19 severity. Patients diagnosed early in the COVID-19 pandemic (January-April 2020) had worse outcomes than those diagnosed later. Specific anti-cancer therapies (e.g. R-CHOP, platinum combined with etoposide, and DNA methyltransferase inhibitors) were associated with high 30-day all-cause mortality.CONCLUSIONS:Clinical factors (e.g. older age, hematological malignancy, recent chemotherapy) and laboratory measurements were associated with poor outcomes among patients with cancer and COVID-19. Although further studies are needed, caution may be required in utilizing particular anti-cancer therapies.
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The Holdridge Life Zone model, Shannon's Entropy Index and Simpson's Diversity Index were used to study the dynamics of vegetation distribution over the past 40 years in the Xinjiang Uygur Autonomous Region (XUAR), China. The resu...
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The Holdridge Life Zone model, Shannon's Entropy Index and Simpson's Diversity Index were used to study the dynamics of vegetation distribution over the past 40 years in the Xinjiang Uygur Autonomous Region (XUAR), China. The results indicated that Holdridge Life Zone diversity was highest in the 1960s, dramatically decreased in the 1970s, and then gradually increased in the 1980s and 1990s. From the 1970s, the environment in XUAR seemed to be increasing in stability, as characterized by a reduction in the number of days of sandy dust storm activity in the 1990s, and an increase in temperature and precipitation leading to an increase in water flow in some rivers. It is possible that both changes in human activities and positive climate change contributed to the Holdridge Life Zone diversity dynamics and more stable environment in XUAR.
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