Search

In solvothermal synthesis of Er-doped NaGdYbF nanocrystals, morphology of the nanoparticles is dependent on the molar ratio of the chelating agent (e.g., trisodium citrate) to the lanthanide ions. Usually, addition of chelating agent is reported to be effective only when the molar ratio is below a critical value usually around 1 for the preparation of Er- and Yb-doped NaYF nanocrystals. In this work, we found that, by increasing the Yb concentration, the critical molar ratio can be up to more than 4 in the preparation of Er-doped NaGdYbF nanocrystals, which provides a new route to control the nanoparticles' size. The result is particularly useful for the synthesis of small Er-doped NaGdYbF nanocrystals with high concentration of the Yb dopant. We also investigated mechanisms on the formation of such particles ( β-NaGdYbF:Er) with large size in a sub-micrometer scale, i.e., the aggregation-induced crystal growth. In addition, upconversion luminescence properties of the powdery samples were studied, which is shown to be dependent both on size of the nanoparticles and on dosage of the trisodium citrate. [ABSTRACT FROM AUTHOR]

In this paper, a rigid–flexible planar parallel manipulator (PPM) actuated by three linear ultrasonic motors for high-accuracy positioning is proposed. Based on the extended Hamilton's principle, a rigid–flexible dynamic model of the proposed PPM is developed utilizing exact boundary conditions. To derive an appropriate low-order dynamic model for the design of the controller, the assumed modes method is employed to discretize elastic motion. Then to investigate the interaction between the rigid and elastic motions, a proportional derivative feedback controller combined with a feed-forward-computed torque controller is developed to achieve motion tracking while attenuating the residual vibration. Then the controller is extended to incorporate an input shaper for the further suppression of residual vibration of flexible linkages. Computer simulations are presented as well as experimental results to verify the proposed dynamic model and controller. The input shaping method is verified to be effective in attenuating residual vibration in a highly coupled rigid–flexible PPM. The procedure employed for dynamic modeling and control analysis provides a valuable contribution into the vibration suppression of such a PPM. [ABSTRACT FROM AUTHOR]

Objective To analyze the differences in clinical characteristics and risk factors in patients with diastolic heart failure and systolic heart failure. Methods A total of 2 088 patients with heart failure were divided into two groups, diastolic heart failure group (EF⩾0.45, n=1 356) and systolic heart failure group (EF<0.45, n=732), according to ejection fraction (EF). The clinical features and related factors affecting the two types of heart failure were compared between two groups. Results There were higher age, higher proportion of women and higher proportion of hypertensive patients in diastolic heart failure group than those of systolic heart failure group, but lower rates of hypoalbuminemia, anemia, renal insufficiency and hyperuricimia. There was higher incidence of functional class I and II in diastolic heart failure group. And compared with systolic heart failure group, there were higher levels of systolic blood pressure, albumin, prealbumin, cholesterol, sodium and serum chloride in diastolic heart failure group, but lower levels of heart rates, creatinine, blood uric acid, potassium and brain natriuretic peptide. Compared with systolic heart failure group, there were lower left ventricular end diastolic volume (LVEDV) and left ventricular end systolic volume (LVESV) in diastolic heart failure group. And there were lower RAS blocker and β-blocker usage, higher statin usage in diastolic heart failure group. Logistic regression analysis showed that gender and hypertension were significantly correlated with diastolic heart failure, and hypoalbuminemia and hyperuricimia were significantly correlated with systolic heart failure. Conclusion Our results show that there are differences in clinical features and risk factors in patients with diastolic heart failure and systolic heart failure. We should take the different treatment and prevention programs for the two kinds of heart failures. [ABSTRACT FROM AUTHOR]

Double helical gear transmission is a very important transmission component. A lot of dynamic models of spur and helical gears for studying dynamic characteristics have been put forward, but the studies on double helical gears are scarce. To study the nonlinear dynamic characteristics of the double helical gear system, the nonlinear dynamic model of double helical gear system was established. Then the dimensionless dynamic model was summarized. Through numerical computation, the nonlinear dynamic characteristic was revealed in some aspect. The vibration amplitude of gear is smaller than the vibration amplitude of pinion at the same direction and the vibration amplitude of the same component at direction is larger than the amplitude of gear at direction. Through the numerical method, we find that there is a plenty of nonlinear dynamic characteristics in the double helical gear system, and thus more research is needed. [ABSTRACT FROM AUTHOR]

In this paper, a nonlinear torsional vibration model with meshing errors, time varying meshing stiffness, damping coefficients and gear backlashes was established and dimensionless equations of the system are derived in the planetary gear train processing device. The paper analyzed the nonlinear dynamic behavior of the device which was used to machine the Circular-Arc-Tooth-Trace cylindrical gear. By using the method of numerical integration, the bifurcation diagrams are obtained and the results indicate that the processing device has abundant bifurcation characteristics with the change of the dimensionless speed, and the damping ratios, gear backlashes and meshing errors of meshing pairs could influence the vibration greatly. The bifurcation diagrams reveal that increasing the damping ratios can change the bifurcation and the chaos can be avoid when the damping ratios are bigger enough, reducing the gear backlashes can reduce the dimensionless displacement amplitudes, increasing the meshing errors can make the bifurcation diagrams shift left for a distance, and alternating load torque with large amplitude will cause complex chaos phenomenon. The study can help to avoid the fatigue failure and instabilities caused by chaos and it also contribute to improving the performance of the processing device. [ABSTRACT FROM AUTHOR]

A series of indium-modified manganese oxide catalysts with different ratios were prepared by the homogeneous precipitation method. The appropriate amount of indium modification has many effects on the MnO x catalysts, such as increasing the specific surface area, increasing the concentration of surfactant Mn4+ and surface oxygen, enhancing the surface acid site strength, and improving the low-temperature activity of the MnO x catalysts. the Mn-InO-6 catalyst (Mn: In = 6:1) showed the best activity, maintaining approximately 100% NO x at conversion rates of 75–200 °C. Indium doping significantly improved the sulfur resistance of the MnO x catalyst with high reversibility and good stability. In situ DRIFTs indicate that the NH 3 -SCR reaction over Mn-InO-6 catalysts follows the Eley-Rideal and Langmuir-Hinshelwood mechanisms. [Display omitted] • A novel NH 3 -SCR catalyst was developed by doping the indium into manganese oxide. • The Mn-InO-6 catalyst showed > 97% conversion of NO x at 75–200 °C. • The doping of Indium increases the number of Brønsted acid sites and Lewis acid sites on the catalyst surface. • The resistance to H 2 O and SO 2 of the Mn-InO-6 catalyst was enhanced significantly. • The mechanism of catalytic of NH 3 -SCR of the novel catalyst was analyzed. [ABSTRACT FROM AUTHOR]

The underdeveloped areas have the characteristics of objective multiplicity and conditional restrictivity during the process of new industrialization, then build an evaluation index system. Based on Analytic Hierarchy Process and Entyopy Method, using Comprehensive Weight Method, this paper measures the new industrialization level of Hubei Province and finds that it is increasing year by year while the whole level is low, and it is just entering into the medium-term of new industrialization. In the future it is important to speed up the course of new industrialization of Hubei Province from five aspects such as push forward integrating IT application with industrialization, improve the persistence of economy and so on. [ABSTRACT FROM AUTHOR]

Based on mechanical models, the creep behavior of carpet yarns after dynamic loading was investigated. For prediction the creep elongation, the frequently used mechanical models reported in the literature were analyzed. The mechanical models which were used in this article were: standard linear model, four-element model, two-component Kelvin's model, and Eyring's model. The obtained creep formulas were fitted to experimental creep data, and the parameters of the model can be obtained using the Marquardt algorithm for nonlinear regression. When comparing the experimental creep curve with the fitted curve from the mechanical model, it is clear that the four-element model explain the experimental creep curve better. During tufting machine stops, the carpet yarns were undergone constant load. The confirmed viscoelastic model will be used to calculate total creep elongation during carpet machine stoppage. Thus, the start-up marks which occurred at carpet machine restarts can be exactly eliminated by adjusting the feeding length according to the creep elongation. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 [ABSTRACT FROM AUTHOR]

Multiplet independent resonance modes can be used to control light–matter interactions beyond the capability of conventional optical resonators. Here we present the design and fabrication of multiplexed gratings in a plasmonic waveguide structure to realize multiplet independent resonance modes. Based on the optimally chosen, low-loss plasmonic TM1 waveguiding mode, the multiplet resonance modes demonstrate relatively high-quality factors, field enhancements, overlapping resonance fields, and identical polarization states, advantageous to resonant control and enhancement of light–matter interactions. By adjusting structure parameters of the constitutive gratings, the respective resonance positions and their resonance intensities can be independently adjusted. Experimentally, the plasmonic structures with multiplexed gratings are fabricated, based on multi-exposure holographic lithography processes, which demonstrate arbitrarily adjustable doublet or triplet resonance modes. • Here we report a plasmonic waveguide structure with multiplexed gratings. • The structures demonstrate multiplet independent resonance modes. • The multiplet resonance positions can be independently and arbitrarily adjusted. • The multiplet modes have high quality factors and overlapping mode fields, etc. • The structures are fabricated and the results are experimentally verified. [ABSTRACT FROM AUTHOR]

• Effects of coupling strength on lasing of quantum emitters on a plasmonic metal grating are elucidated. • Plasmonic lasing of the emitters on the metal gratings takes place only in the strong coupling condition. • Stimulated emission for lasing cannot be induced even as population inversion is achieved at high pumping levels. Plasmonic lasers have been actively studied for nearly two decades, but status of coupling between gain emitters and surface plasmon resonance (SPR) modes and its effect on lasing have not been elucidated. In this work, we have a numerical study on photoluminescence/lasing behaviors of emitters in weak and strong coupling with SPR modes on metal gratings based on a four-level two-electron model for the emitters. The strong coupling is achieved by incorporating high-density emitters in the gain medium on metal gratings. It is found that lasing of the emitters on the metal grating takes place only in the strong coupling condition; and the lasing spectral width can be far less than those of the emitters' intrinsic spontaneous emission and the SPR mode. In the weak coupling condition, there is only spontaneous emission; stimulated emission cannot be induced even when population inversion is achieved at high pumping levels. The results indicate important role of strong coupling in realization of plasmonic lasing. [ABSTRACT FROM AUTHOR]

Cuproptosis, a newly discovered cell death modality, is gaining recognition for its crucial role in antitumor therapy. Here, we demonstrated that Ferredoxin 1 (FDX1), a key gene involved in cuproptosis, is negatively correlated with malignancy and T‐cell exhaustion in head and neck squamous cell carcinoma (HNSCC). Based on these findings, we developed near‐infrared (NIR) light‐controlled nanoparticles (NPs), CuD@PM, which can selectively deliver copper to HNSCC cells and induce cuproptosis in the presence of microneedles loaded with triacetylated azacitidine (TAc‐AzaC) and 808 nm laser irradiation. Intravenous administration of these NPs significantly suppressed tumor growth in HNSCC animal models and enhanced the antitumor immune response. The NIR‐controlled activation of cuproptosis offers great potential as a safe, targeted, and image‐guided antitumor therapy for HNSCC. [ABSTRACT FROM AUTHOR]