Efficient Near-Infrared Quantum Cutting in Tm3＋/yb3＋ Codoped LiYF4 Single Crystals for Solar Photovoltaic

Downconversion （DC） with emission of two near-infrared photons about 1000 nm for each blue photon absorbed was obtained in thulium （Tm3＋） and ytterbium （Yb3＋） codoped yt- trium lithium fluoride （LiYF4） single crystals grown by an improved Bridgman method. The luminescent properties of the crystals were measured through photoluminescence excitation, emission spectra and decay curves. Luminescence between 960 and 1050 nm from yb3＋： 2Fs/2--＋2FT/2 transition, which was originated from the DC from Tm3＋ ions to Yb3＋ ions, was observed under the excitation of blue photon at 465 nm. Moreover, the energy transfer processes were studied based on the Inokuti-Hirayama model, and the results indicated that the energy transfer from Tm3＋ to Yb3＋ was an electric dipole-dipole interaction. The max- imum quantum cutting efficiency approached with 0.49mo1% Tm3＋ and 5.99mo1% Yb3＋. increasing the energy efficiency of crystalline energy part of the solar spectrum. up to 167.5% in LiYF4 single crystal codoped Application of this crystal has prospects for Si solar cells by photon doubling of the high

Nominal Model-Based Sliding Mode Control with Backstepping for 3-Axis Flight Table

Based on nominal model, a novel global sliding mode controller （GSMC） with a new control scheme is proposed for a practical uncertain servo system. This control scheme consists of two combined controllers, One is the global sliding mode controller for practical plant, the other is the integral backstepping controller for nominal model. Modeling error between practical plant and nominal model is used to design GSMC. The steady-state control accuracy can be guaranteed by the integral backstepping control law, and the global robustness can be obtained by GSMC. The stability of the proposed controller is proved according to the Lyapunov approach. The simulation results both of sine signal and step signal tracking for 3-axis flight table are investigated to show good position tracking performance and high robustness with respect to large and parameter changes over all the response time.

Effect of Indole 3-Butyric Acid and Media Type on Adventitious Root Formation in Sheanut Tree (<i>Vitellaria paradoxa</i>C. F. Gaertn.) Stem Cuttings

Shea nuts play an important role in food security for rural folks within sub-Sahara Africa, serving as the main source of income for many people living in Northern Ghana. Unfortunately, the full economic potential of the Sheanut tree has not been fully realized due to the difficulty involved in its domestication. This difficulty in vegetatively propagating sheanut trees has greatly hindered its cultivation and the realization of its true economic potential. Two experiments were conducted to investigate the effects of rooting media and varying indole 3-butyric acid (IBA) concentrations on adventitious root formation in cuttings taken from coppiced sheanut trees. Results indicated that 3000 ppm produced significantly (p 0.05) better rooting (57.5%) than 5000 ppm (30%), 7000 ppm (45.0%) and the control (7.5%). Although the levels of soluble sugars (SS) and total free phenols (TFP) in the cutting were significantly (p 0.05) higher at the end of the experiment (after IBA treatment) compared to the start (prior to IBA treatment), the SS and TFP trends observed did not clearly explain the rooting differences found between the IBA levels investigated. Callus formation was significantly (p 0.05) higher (35.0%) in the control (no IBA). Generally, callus formation decreased with increasing IBA concentration. In the rooting media experiment, rooting was significantly (p 0.05) higher in the rice husk medium (35.0%) compared to that in the palm fiber (18.3%), saw dust (14.1%) and top soil (16.7%) media.

Stiffness of Postural Alignment System Based on 3-Axis Actuators for Large Aircraft Components

Aircraft digital flexible assembly fixture and technologies are widely used in developed countries, while the traditional jig-based assembly mode is still used in China. The application study of aircraft digital flexible assembly system is just beginning in our country recently. To meet the requirements of automated posture alignment and join in digital assembly system for large aircraft components, a novel fitting fixture called 3-axis actuator is developed. On the basis of the actuators, three kinds of posture alignment system for large aircraft components are proposed, including the non-redundant system, the redundant actuating system, and the redundant leg system, and their constitutions and properties are introduced. Through deriving the feeding transmission stiffness model of single actuator and analyzing the inverse kinematics of these systems, the relationship between the external force and the changes of position and orientation of large aircraft component is obtained, and then the postural alignment stiffness models are established. With the method mentioned above, the postural alignment stiffness of three systems is computed by using the algebraic formulate, and the results show that redundant properties can increase system＇s postural alignment stiffness. As an example, a optimized layout of the assembly system for a given model of aircraft is developed, the results of application show that the layout has many advantages, such as high accuracy, stiffness, stability, reliability, efficiency and flexible, which can satisfy the requirement of aircraft digital assembly system well. The proposed study of postural alignment stiffness for different systems can supply the theoretic support for the optimization layout design of aircraft digital assembly system, and contribute to evaluate the system working performance of systems.

QFT Robust Control Design for 3-Axis Flight Table Servo System with Large Friction

The 3-axis flight table is an important device and a typical high performanceposition and speed servo system used in the hardware-in-the-loop simulation of flight controlsystem. Friction force and uncertainty are the main characteristics in the 3-axis flight table servosystem. Based on the description of dynamic and static model of a nonlinear Stribeck frictionmodel, and taking account of the practical uncertainties of 3-axis flight table servo system, theQFT controller is designed. Simulation and realtime results are presented.

Physiological Dynamics and Transcriptomic Analysis of Cut Roses‘Carola’Treated with KNO_(3)

The consumption of cut roses(Rosa hybrida)has always ranked first in the world.However,it is vulnerable to rapid petal and leaf wilting due to leaf stomatal water loss,which seriously affects its ornamental quality and economic value.Stomatal movement,a key in plant physiological processes,is influenced by potassium and nitrate.Advancing comprehension of its physiological and molecular mechanism holds promise for preserving the freshness of cut roses.This study observed the impacts of different concentrations of KNO_(3) vase treatments on stomatal opening and water loss in cut rose‘Carola’leaves,as well as their transcriptional responses to KNO_(3).Water loss rates were influenced by KNO_(3) concentrations,with the 25 and 75 mmol/L treatments exhibiting the highest water loss rates.The stomatal aperture reached its widest value when treated with 75 mmol/L KNO_(3).Transcriptional sequencing analysis was performed to identify differentially expressed genes(DEGs)of which 5456 were up-regulated,and 6607 were down-regulated associated with photosynthesis,starch and sucrose metabolism,metabolic pathways,plant-pathogen interaction,plant hormone signal transduction,and related pathways.246 DEGs were selected related to response to KNO_(3) treatment,of which gene ontology(GO)enrichment were nitrate and terpenoid metabolism,ion transport,and response to stimuli.Further heatmap analysis revealed that several genes related to nitrate transport a metabolism,K+transport,vacuoles,and aquaporin were in close association with the response to KNO_(3) treatment.Weighted gene co-expression network analysis(WGCNA)revealed that hub genes,including LAX2,TSJT1,and SCPL34 were identified in turquoise,black,and darkgreen module.Transcription factors such as NAC021,CDF3,ERF053,ETR2,and ARF6 exhibited regulatory roles in the response to KNO_(3) treatment under light conditions.These findings provide valuable insights into the physiological and molecular mechanisms underlying the response of cut rose leaves to KNO_(3) treatment.

准连续c切Er,Yb:YAl_(3)(BO_(3))_(4)激光器的偏振操控

通过构建谐振腔模型,分析了各向同性固体激光器中两个本征模式相干叠加后的光斑奇异特征。并且实验验证了在不使用任何特定的腔内光学偏振选择元件的情况下,在二极管泵浦的准连续c切Er,Yb:YAl_(3)(BO_(3))_(4)激光器中可以有效操控1.6μm输出激光的偏振态。实现了从部分偏振态转化成稳定的线偏振态,其线偏振方向为可切换的正交特殊情况,均具有21 dB的偏振消光比。同时通过光斑对比,验证了激光器的线偏振输出来源于两个正交本征模式的相干叠加。文中为c切Er,Yb:YAl_(3)(BO_(3))_(4)激光器线偏振光的直接输出与偏振态的调控提供了可靠的方案。

Effect of Different Indole-3-Buteric Acid(IBA)Concentrations and Cutting Types on Plane Trees(Platanus orientalis L.)

Effects of different Indole-3-Buteric Acid （IBA） concentrations （0, 1 000, 1 500 and 2 500 ppm） and curing types （soft wood, semi hard and hard wood） of plane tree were investigated with Randomized Complete Block Design （RCBD） at the Agricultural research station, Charsadda. The maximum survival percentage, plant height （cm）, root length （era）, numbers of roots and root weight per cutting were significantly higher in hard wood cuttings. IBA concentration had no speculative effect on plane tree cuttings. Thus, hard wood cutting was the best choice for plan tree propagation.

Rooting of Stem Cuttings with Different Indole 3 Butyric Acid (IBA) Treatments and Development of Micropropagation Protocol for <i>Piper betle</i>L. Node Culture

The present study, conducted during 2016 and 2017 seasons, aimed to investigate the effect of IBA on rooting of Piper betle L. stem cuttings (softwood and semi-hardwood). The experiment was undertaken in misting house field 2 UPM using the sand media to determine the adventitious roots initiation and development using the histological method. The cuttings were treated with different IBA concentrations (0, 500, 1000, 1500 and 2000 mg/L). The nodes explants were used in the development of a protocol for in vitro propagation of P. betle L., with different concentrations of Clorox with different times of immersion (20% Clorox 10 minutes, 30% Clorox 10 minutes, 20% Clorox 20 minutes, and 30% 20 minutes). In multiplication of the plantlets, Murashige and Skoog (MS) medium with different concentrations of BAP (0, 0.5, 1.0, 2.0 mg/L) were used to investigate the rooting of the explants. The results indicated that the types of the cuttings were different in the rooting capacity and the length of the roots. Moreover, it was found that in comparison with the control treatment, by a rise in the concentrations of the IBA, there was a significant upsurge in the rooting percentage, the root diameter, and the number of the roots. The results indicated that the types of cutting with 1000, 1500 and 2000 mg/L IBA perform better in the root percentage (100%) in the semi hardwood cuttings. The best results, however, were 2000 mg/L IBA in the semi hardwood cuttings, with the number of the roots to be 35.05, and the fresh weight of the roots to be 3.94 g, the dry weight of the roots to be 0.33 g, the length of the roots to be 391.88 cm, the roots diameter to be 1.21 mm, the surface area of the roots to be 121.83 cm2, and the root volume to be 2.99 cm3. Nonetheless, the optimal concentration of Clorox with the time immersion was 20% with the 20-minute immersion time, which produced a shoot induction percentage of 30% dead explants and a mean number of 70.00 shoots per explant and the optimal concentration of benzylaminopurine (BAP) at 1.0 mg/L. It is of note that a shoot induction percentage of 22.29% and a mean number of 4.1% number of auxiliary bud per treatment. P. betle shoots in MS medium without PGR MS (0.0) yielded a good rooting.

Synergistically Toughening Effect of SiC Whiskers and Nanoparticles in Al_2O_3-based Composite Ceramic Cutting Tool Material

In recent decades, many additives with different characteristics have been applied to strengthen and toughen Al2O3-based ceramic cutting tool materials. Among them, SiC whiskers and SiC nanoparticles showed excellent performance in improving the material properties. While no attempts have been made to add SiC whiskers and SiC nanoparticles together into the ceramic matrix and the synergistically toughening effects of them have not been studied. An Al2O3-SiCw-SiC np advanced ceramic cutting tool material is fabricated by adding both one-dimensional SiC whiskers and zero-dimensional SiC nanoparticles into the Al2O3 matrix with an effective dispersing and mixing process. The composites with 25 vol% SiC whiskers and 25 vol% SiC nanoparticles alone are also investegated for comparison purposes. Results show that the Al2O3-SiCw-SiCnp composite with both 20 vo1% SiC whiskers and 5 vol% SiC nanoparticles additives have much improved mechanical properties. The flexural strength of Al2O3-SiCw-SiCnp is 730＋ 95 MPa and fracture toughness is 5.6 ± 0.6 MPa.m1/2. The toughening and strengthening mechanisms of SiC whiskers and nanoparticles are studied when they are added either individually or in combination. It is indicated that when SiC whiskers and nanoparticles are added together, the grains are further refined and homogenized, so that the microstructure and fracture mode ratio is modified. The SiC nanoparticles are found helpful to enhance the toughening effects of the SiC whiskers. The proposed research helps to enrich the types of ceramic cutting tool and is benefit to expand the application range of ceramic cutting tool.

Machinability of Hastelloy C-276 Using Hot-pressed Sintered Ti(C_7N_3)-based Cermet Cutting Tools

C-276 nickel-based alloy is a difficult-to-cut material. In high-speed machining of Hastelloy C-276, notching is a prominent failure mode due to high mechanical properties of work piece, which results in the short tool life and low productivity. In this paper, a newly developed Ti（C7N3）-based cermet insert manufactured by a hot-pressing method is used to machine the C-276 nickel-based alloy, and its cutting performances are studied. Based on orthogonal experiment method, the influence of cutting parameters on tool life, material removal rates and surface roughness are investigated. Experimental research results indicate that the optimal cutting condition is a cutting speed of 50 m/min, depth of cut of 0.4 mm and feed rate of 0.15 mm/r if the tool life and material removal rates are considered comprehensively. In this case, the tool life is 32 min and material removal rates are 3000 mm^3/min, which is appropriate to the rough machining. If the tool life and surface roughness are considered, the better cutting condition is a cutting speed of 75 m/min, depth of cut of 0.6 mm and feed rate of 0.1 mm/r. In this case, the surface roughness is 0.59μm. Notch wear, flank wear, chipping at the tool nose, built-up edge（BUE） and micro-cracks are found when Ti（C7N3）-based cermet insert turned Hastelloy C-276. Oxidation, adhesive, abrasive and diffusion are the wear mechanisms, which can be investigated by the observations of scanning electron microscope and energy-dispersive spectroscopy. This research will help to guide studies on the evaluation of machining parameters to further advance the productivity of nickel based alloy Hastelloy C-276 machining.

Infrared quantum cutting conversion luminescence of Tb(0.7)Yb(3):FOV

The infrared quantum cutting of oxyfluoride nanophase vitroceramics Tb（0.7）Yb（3）：FOV has been studied in the present paper. The actual quantum cutting efficiency formula calculated from integral fluorescence intensity is extended to the case of Tb（0.7）Yb（3）：FOV. The visible and the infrared fluorescence spectra and their integral fluorescence intensities are measured from static fluorescence experiment. Lifetime curve is measured from dynamic fluorescence experiment. It is found that the total actual quantum cutting efficiency n of the excited 5D4 level is about 93.7%, and that of excited （5D3, 5G6） levels is 93.5%. It is also found that the total theoretical quantum cutting efficiency upper limit ？~x^Yb of the 485.5 nm excited 5D4 level is about 121.7%, and that of 378.5 nm excited （5D3, 5G6） levels is 137.2%.

1-3型压电复合材料性能及声场特性分析

1-3型压电复合材料以其优异的性能,被广泛应用于换能器的制造。该文基于切割-填充法制备实验和仿真方法,对复合材料压电柱不一致性以及其对声场的影响展开研究。在仿真中发现压电柱高度、长度和宽度不一致性均会对压电复合材料声场及谐振频率产生影响,声场整体朝一侧偏转,旁瓣也随之偏转,聚焦位置的声压减小6.5%左右,同时压电复合材料侧面产生杂波。在实验中发现压电柱谐振频率具有不一致性,而压电柱尺寸较大的复合材料阻抗曲线向右偏移。该文结合仿真与实验方法,建立压电柱不一致与复合材料阻抗和声场的联系,为复合材料制备质量和性能分析提供新方法。

Concentration effect of the near-infrared quantum cutting of 1788-nm luminescence of Tm^(3+) ion in(Y_(1-x)Tm_x)_3Al_5O_(12) powder phosphor

In the present paper, the concentration effect of near-infrared quantum cutting of Tm3＋ ion in （Y1-xTmx）3Al5Ol2 powder phosphor is studied by means of experiments and calculations. In addition, the absorption spectra, visible-to-near- infrared excitation and emission spectra, and fluorescence lifetimes are measured. It is found that （Y1-xTmx）3Al5O12 powder phosphor has a strong four-photon near-infrared quantum cutting luminescence of 1788.0-nm 3F4 →3H6 fluores- cence of Tm3＋ ion, when excited by 357.0-nm light. It is also found that the up-limit of the four-photon near-infrared quantum cutting luminescence efficiency of （Yo.700Tmo.300）3Al5 O12 powder phosphor is approximately 302.19%. To the knowledge of the authors, this is the first time that a near-infrared quantum cutting efficiency up-limit exceeding 300% has been reported. The results of this manuscript are valuable in aiding the probing of the new generation Ge solar cell.

切削液对金刚石线锯切割β-Ga_(2)O_(3)晶片表面质量的影响

为了开发出更适合β-Ga_(2)O_(3)晶片切片的切削液,探讨金刚石线锯切片过程中不同切削液对β-Ga_(2)O_(3)晶片表面质量的影响,通过测量接触角和表面张力,研究不同切削液对β-Ga_(2)O_(3)晶片表面的润湿性。采用粗糙度测量仪、非接触式测厚仪和扫描电镜(SEM)对晶片表面进行测试表征,研究去离子水、添加AEO-9的水基切削液和乳化切削液在不同工艺参数下对切割(010)面β-Ga_(2)O_(3)晶片的表面粗糙度、表面形貌、总厚度变化以及亚表面损伤层深度的影响。结果表明:与去离子水相比,添加AEO-9的水基切削液和乳化切削液均能有效降低β-Ga_(2)O_(3)表面的接触角和表面张力,表明2种切削液均可提高晶片表面润滑性;乳化切削液的效果随着工艺参数的变化而波动很大,只有在低切削热和大切削力的条件下,才能明显优化晶圆表面质量,而水基切削液可稳定地获得较高的晶片表面质量,更适用于β-Ga_(2)O_(3)晶片切割。

New Virtual Cutting Algorithms for 3D Surface Model Reconstructed from Medical Images

This paper proposes a practical algorithms of plane cutting, stereo clipping and arbitrary cutting for 3D surface model reconstructed from medical images. In plane cutting and stereo clipping algorithms, the 3D model is cut by plane or polyhedron. Lists of edge and vertex in every cut plane are established. From these lists the boundary contours are created and their relationship of embrace is ascertained. The region closed by the contours is triangulated using Delaunay triangulation algorithm. Arbitrary cutting operation creates cutting curve interactively. The cut model still maintains its correct topology structure. With these operations, tissues inside can be observed easily and it can aid doctors to diagnose. The methods can also be used in surgery planning of radiotherapy.

Hybrid 3D printed three-axis force sensor aided by machine learning decoupling

Identification of magnitude and orientation for spatially applied loading is highly desired in the fields of not only the machinery components but also human-machine interaction.Despite the fact that the 3-axis force sensor with different structures has been proposed to measure the spatial force,there are still some common limitations including the multi-step manufacturing-assembly processes and complicated testing of decoupling calibration.Here,we propose a rapid fabrication strategy with low-cost to achieve high-precision 3-axis force sensors.The sensor is designed to compose of structural Maltese cross base and sensing units.It is directly fabricated within one step by a hybrid 3D printing technology combining deposition modeling(FDM)with direct-ink-writing(DIW).In particular,a machine learning(ML)model is used to convert the strain signal to the force components.Instead of a mount of calibration tests,this ML model is trained by sufficient simulation data based on programmed batch finite element modeling.This sensor is capable of continuously identifying a spatial force with varying magnitude and orientation,which successfully quantify the applied force of traditional Chinese medicine physiotherapy including Gua Sha and massage.This work provides insight for design and rapid fabrication of multi-axis force sensors,as well as potential applications.

Taper Angle Correction in Cutting of Complex Micro-mechanical Contours with Ultra-Short Pulse Laser

The objective of this work was to investigate the possibility of taper angle correction in cutting of complex micro-mechanical contours using a TruMicro ultra-short pulse laser in combination with the SCANLAB precSYS micro machining sub system. In a first step, the influence of the process parameters on the kerftaper angle of metallic alloys was systematically investigated without beam inclination. A set of base parameters was derived for the subsequent investigations. In a second step, the kerftaper angle was controlled by static beam inclination. In a third step, the same optics was used in its dynamic precession mode to fabricate micro-mechanical components of complex contours with perpendicular 0~ taper angles. It was found that taper angle adjustments of up to 7.5~ are possible with the used setup for cutting applications. Taper angle control is possible both in the static beam inclination mode and in the dynamic precession mode. The static mode could be interesting for contours with sharp inner radii and for achieving faster cutting times similar to results with fixed optics, but would require excellent synchronization of beam inclination and axis motion. The dynamic precession mode would allow an easier integration of the optics into a laser machine but will result in longer cutting times and limitations with respect to achievable inner radii.

Low temperature,IBA concentrations and optimal time for adventitious rooting of Eucalyptus benthamii mini-cuttings

Eucalyptus benthamii is a forest species of economic interest that has difficulty with seed production and also is considered to have difficulty with adventitious rooting using propagation techniques, such as cutting or mini-cutting. We aimed to assess the adventitious rooting percentage under different storage times in low temperatures and at various IBA （indole-3-butyric acid） concentrations to determine the optimal time of permanence for rooting Eucalyptus benthamii minicuttings in a greenhouse. Shoots collected from mini-stumps cultivated in a semi-hydroponic system were used to obtain the mini-cuttings. For the first experiment, the mini-cuttings were stored at 4℃ for 0 （immediate planting）, 24, 48, 72, 96 and 120 h. The second experiment evaluated the rooting dynamic to determine the optimal time of permanence for minicuttings in a greenhouse. The basal region of the mini-cutting was treated with various IBA solutions： 0 （free of IBA）, 1,000, 2,000, 3,000 and 4,000 mg.L^-1. Every seven days （0 （immediate planting）, 7, 14, 21 and 28 days）, destructive sampling of the mini-cuttings was performed to evaluate the histology of the adventitious rooting. Eucalyptus benthamii minicuttings should be rooted immediately after the collection of the shoots. The 2,000 mg.L^-1 IBA concentration induced a greater speed and percentage of adventitious rooting, and an interval of 35 to 42 days was indicated for permanence of the mini-cuttings in the greenhouse. Expo- sure to low temperature induced adventitious root formation with diffuse vascular connections.

TC4钛合金HF-HNO_(3)化学抛光的表面质量和元素机理分析

为了提升电火花线切割(Wire cut Electric Discharge Machining,WEDM)加工后的TC4钛合金表面质量,减少表面重熔层厚度,采用不同浓度配比(1∶4、1∶6和1∶8)的HF-HNO_(3)酸蚀溶液对钛合金试件进行化学抛光处理。实验结果表明,HF-HNO_(3)酸蚀溶液能使钛合金重熔层得到显著去除,表面微裂纹得到有效控制;当HF-HNO_(3)酸蚀溶液的浓度配比为1:6时,试件能获得最低的表面粗糙度和最大的表面粗糙度下降率,并且抛光前后钛合金表面元素含量发生了不同程度的变化,Ti、Al和V元素质量分数分别提高了21.5%、41.3%和13.2%,而O、C元素质量分数分别降低了82.5%和33.6%;HF-HNO_(3)酸蚀溶液可显著改善TC4钛合金试件电火花线切割加工后的表面缺陷。钛合金重熔层结构的主要成分与化学抛光后氧化膜的主要成分相似,但与氧化膜的结构不同,这对TC4钛合金试件表面质量提升具有重要意义。