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Traditional joint replacement surgery faces the risk of enormous trauma and secondary revision while using medication to relieve symptoms can cause bone thinning, weight gain and interference with the patient’s pain signalling. Medical research has therefore focused on minimally invasive solutions for implanting tissue-engineered scaffolds to induce cartilage regeneration and repair. In cartilage tissue engineering, there are still technical barriers to seed cells, scaffold construction techniques, mechanical properties, and the regulation of the internal environment on the transplanted material. This issue focuses on the development of cartilage repair, cutting-edge discoveries, manufacturing technologies, and the current technological queries still faced in cartilage regenerative medicine research. The articles in this collection cover the coordination of physical and biochemical signals, genes, and regulations by the extracellular environment.

A transfer reaction and cluster-decay experiment, C( O, Mg α+ Ne)α, was performed at a beam energy of 96 MeV. Both recoil and decay α particles were detected in coincidence, allowing us to deduce the energy-momentum of a Ne fragment. A number of resonant states of Mg were reconstructed up to an excitation energy of approximately 30 MeV. Owing to the experimentally achieved excellent resolutions of the Q-value and excitation-energy spectra, the relative decay widths for each resonant state in Mg to various final states of Ne were extracted, along with the total decay width. The obtained results provide good testing ground for theoretical descriptions of multiple clustering configurations in Mg.

In three-dimensional measurement of large-scale parts, such as car bodies and aircraft wings, massive points (up to hundreds of millions) are collected. If all point cloud data is processed, a large amount of computing resources and storage space will be consumed. It is an important task to reduce the burden of processing while maintaining the feature of the point cloud as much as possible. This paper proposes a novel point cloud simplification method using local conditional information that is utilized to evaluate the features of each point in point clouds.The proposed method can reduce the size of point clouds while reserving significant features. Firstly, the original information of each point is evaluated by calculating the curvature of the original point cloud. Secondly, the point with the maximal information is selected and reserved in the target point cloud that will be updated as the alternative point cloud after simplification. The conditional information of each rest point is evaluated by the neighborhood and updated to the information of the current point, which attenuates with the distance from the other reserved points. Finally, the point with the maximal information is reserved iteratively until the number of points reserved satisfies the requirements of simplification according to enterprise needs. Experiments verify the effectiveness and performance of the proposed method. The experimental results indicate that the proposed method performs much better on feature retention than Voxel simplification and Curvature simplification.

Recently, the efficiency of CdTe thin film solar cell has been improved by using new type of window layer Mg x Zn1−x O (MZO). However, it is hard to achieve such a high efficiency as expected. In this report a comparative study is carried out between the MZO/CdTe and CdS/CdTe solar cells to investigate the factors affecting the device performance of MZO/CdTe solar cells. The efficiency loss quantified by voltage-dependent photocurrent collection efficiency (η C(V′)) is 3.89% for MZO/CdTe and 1.53% for CdS/CdTe solar cells. The higher efficiency loss for the MZO/CdTe solar cell is induced by more severe carrier recombination at the MZO/CdTe p–n junction interface and in CdTe bulk region than that for the CdS/CdTe solar cell. Activation energy (E a) of the reverse saturation current of the MZO/CdTe and CdS/CdTe solar cells are found to be 1.08 eV and 1.36 eV, respectively. These values indicate that for the CdS/CdTe solar cell the carrier recombination is dominated by bulk Shockley–Read–Hall (SRH) recombination and for the MZO/CdTe solar cell the carrier recombination is dominated by the p–n junction interface recombination. It is found that the tunneling-enhanced interface recombination is also involved in carrier recombination in the MZO/CdTe solar cell. This work demonstrates the poor device performance of the MZO/CdTe solar cell is induced by more severe interface and bulk recombination than that of the CdS/CdTe solar cell.

Hundreds of images with the same polarization state are first registered to compensate for the jitters during an observation and then integrated to realize the needed spatial resolution and sensitivity for solar magnetic field measurement. Due to the feature dependent properties of the correlation tracker technique, an effective method to select the feature region is critical for low-resolution full-disk solar filtergrams, especially those with less significant features when the Sun is quiet. In this paper, we propose a region extraction method based on a Hessian matrix and information entropy constraints for local correlation tracking (CT) to get linear displacement between different images. The method is composed of three steps: (1) extract feature points with the Hessian matrix, (2) select good feature points with scale spaces and thresholds, and (3) locate the feature region with the two-dimensional information entropy constraints. Both the simulated and observational experiments demonstrated that our region selection method can efficiently detect the linear displacement and improve the quality of a ground-based full-disk solar magnetogram. The local CT with the selected regions can obtain displacement detection results as good as the global CT and at the same time significantly reduce the average calculation time.

Trifluoromethane is an important etching gas in semiconductor industries as the fluorine source in reactive etching plasma. Electron impact excitations into the dissociation states are essential for plasma modeling. By employing an angle-resolved electron energy loss spectrometer, the generalized oscillator strengths (GOSs) for the valence-shell excited states have been determined at an absolute scale utilizing the crossed-beam based relative flow technique. The measurement was performed with an incident electron energy of 1500 eV at an energy resolution of about 70 meV. The corresponding optical oscillator strengths are also obtained by extrapolating the measured GOSs to the limit of zero momentum transfer. The extrapolated data and fitted linewidths are used to reproduce the photoabsorption spectra and compare with the available experimental and theoretical results. In addition, the integral cross sections from the excitation threshold to 5000 eV of the associated excited states have been derived by using the BE-scaling method. The resulted data can not only be used in plasma models but also serve as a benchmark for further theoretical calculations.

A systematic study on forward–backward (FB) multiplicity correlations from large systems to small ones through a multi-phase transport model (AMPT) has been performed and the phenomenon that correlation strength increases with centrality can be explained by taking the distribution of events as the superposition of a series of Gaussian distributions. It is also found that correlations in the plane can imply the shape of the event. Furthermore, long-range correlations originate from the fluctuations associated with the source information. FB correlations allow us to decouple long-range correlations from short-range correlations, and may provide a chance to investigate the α-clustering structure in initial colliding light nuclei as well. It seems the tetrahedron 16O + 16O collision gives a more uniform and symmetrical fireball, that emits the final particles more isotropically or independently in the longitudinal direction, indicating that the forward–backward multiplicity correlation could be used to identify the pattern of α-clustered 16O in future experiments.

Tissue engineered cartilaginous constructs have meet great advances in the past decades as a treatment for osteoarthritis, a degenerative disease affecting people all over the world as the population ages. Scaffold-free tissue engineered constructs are designed and developed in recent years with only cells and cell-derived matrix involved. Scaffold-free tissue constructs do not require cell adherence on exogenous materials and are superior to scaffold-based constructs in (a) relying on only cells to produce matrix, (b) not interfering cell–cell signaling, cell migration or small molecules diffusion after implantation and (c) introducing no exogenous impurities. In this review, three main scaffold-free methodologies for cartilage tissue engineering, the cell sheet technology, the phase transfer cell culture-living hyaline cartilage graft system and the cell aggregate-based (bottom-up) methods, were reviewed, covering mold fabrication, decellularization and 3D bioprinting. The recent advances, medical applications, superiority and drawbacks were elaborated in detail.

Method of μ synthesis based on self-contained structured singular value theory provides a resolution for control system with uncertain character. It makes the control system to have enough robustness and optimal control performance. When the aircraft is flying in the dense aerosphere, the autopilot of the aircraft is facing such a control system with a lot of uncertain elements. To obtain the optimal robustness in such case, the method of μ synthesis is used to design the autopilot in this paper. Also the result of simulation is tested and analysed. And the final analysis indicates the adopted controller has an effective result to the uncertainty.

In response to a series of problems in the actual use of a certain type of tank fire control system and autoloader, such as many sudden failures, difficulties in diagnosing and locating failures, and complex maintenance and guarantee, a testing equipment is designed for the gun control box and autoloader, which is used to monitor the status of the gun control box and autoloader, and store the test data in real time. By comparing the test data and analysing the abnormal problems that occur in the work of the gun control box and the autoloader, it realises the monitoring of the working condition of the tank gun control box and the autoloader components, providing effective data support for the next step of repair.

We study dynamical behaviors of a Bose–Einstein condensate (BEC) containing a dark soliton reflected from potential wells and potential barriers, respectively. The orientation angle of the dark soliton and the width of the potential change play key roles on the reflection probability R s. Variation of the reflection probability with respect to the orientation angle θ of the dark soliton can be well described by a cosine function R s ∼ cos [λ(θ – π/2)], where λ is a parameter determined by the width of the potential change. There are two characteristic lengths which determine the reflection properties. The dependence of the reflection probability on the width of the potential change shows distinct characters for potential wells and potential barriers. The length of the dark soliton determines the sensitiv width of potential wells, whereas for potential barriers, the decay length of the matter wave in the region of the barrier qualifies the sensitive width of the barrier. The time evolution of the density profiles of the system during the reflection process is studied to disclose the different behaviors of matter waves in the region of the potential variation.

The National Solar Observatory is currently developing the Accurate Infrared Magnetic Field Measurements of the Sun (AIMS). The primary mirror of the AIMS solar telescope is an off-axis parabolic with a diameter of 1 m and with a large off-axis amount of 1 m. Due to the surface figure of the primary mirror under the used state is directly related to image quality of the whole system, a computer-generated hologram (CGH) is carried out to test the primary mirror, and the test results are used to polish the mirror to a higher surface accuracy. However, the fact that the distortion exists in the testing results leads to the failure of a further guide to deterministic optical processing. In this paper, a distortion correction method is proposed, which uses an orthogonal set of vector polynomials to mapping the coordinates of the mirror and the pixels of fringes, and then an interpolation method is adopted to obtain the corrected results. The testing accuracy by using CGH is also verified by an auto-collimate test experiment. According to the distorted corrected results, the root-mean-square of the surface figure is about 1/50λ (λ = 632.8 nm) after polishing.

A multi-nucleon transfer and cluster decay experiment, Li( B, C + Be) , is conducted at an incident beam energy of 55 MeV. This reaction channel has a significantly large Q-value, which favors populating the high lying resonant states in C. The decay paths, from these resonances to various states of the final nucleus Be, can be selected, owing to the experimentally achieved optimal resolution of the Q-value spectrum. A number of resonant states are reconstructed from the forward emitting Be + fragments, and their major molecular structures can be detected according to the selective decay paths and relative decay widths. A state at 22.4(2) MeV validates the previously measured and theoretically predicted band head of the positive-parity -bond linear-chain molecular band. Two additional resonances at 22.9(2) and 24.2(2) MeV are identified and consistent with the predicted and members of the same molecular band, thus providing novel evidences for the existence of the exotic clustering chain structure in neutron-rich carbon isotopes. A few high energy resonances, which also indicate the presence of the -bond molecular structure, are observed; however, further studies are still required to clarify their ascription in band systematics.

Ni-Al2O3 nano-composite coating was prepared on the ASP30 powder metallurgical steel surface for semiconductor encapsulation mould by using electrodeposition method. Effects of Al2O3 contents on microstructure, microhardness and wear resistance of composite coating were analyzed. Results demonstrate that due to refined crystalline strengthening, dispersion strengthening and high-density dislocation strengthening of Al2O3 nanoparticles in uniform distribution, Ni-Al2O3 nano-composite coating has more compact structure and smaller grain size compared to the pure Ni coating, which are conducive to increase microhardness and wear resistance of the coating significantly. Neither too low nor too high Al2O3 contents is beneficial to improve microhardness and wear resistance of composite coating. The pure Ni coating has serious adhesion wearing, while the nano-composite coating with the moderate Al2O3 content has the best performance and it mainly has mild abrasive wear, accompanied with some adhesion wearing. Relatively serious adhesion wearing occurs on the wear surface of pure Ni coating. Differently, wearing surface of Ni-Al2O3 nano-composite coating is mainly dominated by mild abrasive wear, accompanied with some adhesion wearing. Neither too low and too high Al2O3 content is conducive to improve microhardness and wear resistance of composite coating.

Coincidence measurements of breakup fragments in reactions of with at energies around and above the Coulomb barrier were carried out using a large solid-angle covered detector array. Through the Q values along with the relative energies of the breakup fragments, different breakup components (prompt breakups and delayed breakups) and different breakup modes ( , , , and ) are distinguished. A new breakup mode, , is observed in -induced reactions at energies above the Coulomb barrier. Correlations between breakup modes and breakup components as well as their variations with the incident energy are investigated. The results will help us better understand the breakup effects of weakly bound nuclei on the suppression of a complete fusion, particularly for the above-barrier energies.

Aiming at the technical challenge of spinning forming used for ultra long tubular parts, a new spinning technology based on floating die and synchronous rotation of both ends of the spinning blank was put forward. That is die ring spinning, which is divided into die ring forward spinning and die ring backward spinning. The die ring spinning utilizes to improve the stress condition of deformed metal parts and enhances the fluidity of crystal phase structure along the slip surface. It can not only eliminate the phenomenon of material bulging before spinning wheels, but also improve the straightness and reduce the ellipticity of pipes at the same time.

Ammunition-feed system is a key system in special vehicles equipped with shooting weapons (such as main battle tank, self-propelled artillery, etc.). The working reliability of ammunition-feed system is very important for the operation of special vehicles. However, in terms of the use of ammunition-feed system of special vehicles in active service in various countries around the world, its reliability is often not satisfactory, which is the main reason that ammunition-feed system has not been adopted in American main battle tanks up to now. Firstly, the paper points out that one of the main causes of the poor reliability of ammunition-feed system lies in the problems existing in the traditional test methods, these problems are analyzed concretely, and puts forward the solution. —The test technology is adopted based on the integration of shooting simulation and driving simulation. Then, the paper states based on the basic concept of the test of technology of shooting simulation and driving simulation and type of simulation test device, working principle, basic function and technical characteristics, and This paper puts forward the concrete implementation of the integrated test technology of shooting simulation and driving simulation in the performance test of ammunition-feed system in special vehicles, and analysis of effects is applied. Finally, the conclusion is drawn that the application of the simulation test technology will improve the overall performance of the ammunition-feed system significantly.

The Stokes polarimeter based on liquid crystal variable retarders (LCVRs) is envisaged as a promising novel technique for polarization measurement in space applications due to the inherent advantage of eliminating the need for conventional rotating polarizing optics and increasing the measuring speed. However, the intrinsic multi-beam interference in LCVRs limits its polarization accuracy by several percent. How to eliminate the influence of the interference effect becomes an urgent issue for the liquid-crystal-based Stokes polarimeter. The present study introduces a simplified but effective interference model based on the thin-film optics and polarized light theory to simulate the relationship between the interference effect of the LCVRs-based Stokes polarimeter and the polarization accuracy. The simulation results show that the transmittance variation of LCVR with the derived voltage is caused by multi beam interference between the indium tin oxide (ITO) film and the liquid crystal within LCVR, which produces a few percent of instrumental polarization. The instrumental polarization is about 0.01 and different for different wavelengths. An optimization method was proposed to reduce the instrumental polarization to 0.002, effectively improving the polarization sensitivity of the Stokes polarimeter limited by the interference. In addition, an experimental setup was built up to measure and analyze the influence of the interference effect of the LCVRs-based Stokes polarimeter on the polarization accuracy before and after the optimization. The experiment results are in good agreement with the simulation.

We demonstrate a novel polarization control system based on a gradient descent algorithm, applied to a 450-km optical frequency transfer link. The power of the out-loop beat note is retrieved by controlling the polarization state of the transferred signal, with a recovery time of 24 ms, thereby ensuring the long-term evaluation of the fiber link. As a result, data utilization is enhanced from 70% to 99% over a continuous measurement period of ∼12 h. A fractional transfer instability of 7.2 × 10−20 is achieved at an integration time of 10000 s. This work lays the foundation for the comparison of a remote optical clock system via a long-haul optical fiber link.

The Advanced Space-based Solar Observatory (ASO-S) is a mission proposed by the Chinese Solar Physics Community. As one of the three payloads of ASO-S, the Full-disc Magneto-Graph (FMG) will measure the photospheric magnetic fields of the entire solar disk with high spatial and temporal resolution, and high magnetic sensitivity, where liquid crystal variable retarder (LCVR) is the key to whether FMG can achieve its scientific goal. So far, there is no space flight experience for LCVR. Therefore, irradiation study for LCVRs becomes more important and urgent in order to make sure their safety and reliability in space application. In this paper, λ irradiation, proton irradiation, and ultra-violet (UV) irradiation are tested for LCVRs respectively. The optical and chemical properties during irradiation tests are measured and analyzed. For optical properties, there is no significant change in those parameters FMG payload concerned except the retardation. Although there is no drastic degradation in the retardation versus voltage during irradiations, the amount of retardation variation is much higher than the instrument requirements. Thus, an in-flight retardation versus voltage should be added in FMG payload, reducing or even avoiding the impact of retardation change. For chemical properties, the clearing point and birefringence of the LC materials almost have no change; the ion density dose not change below 60 krad[Si], but begin to increase dramatically above 60 krad[Si].

For solving the applicability of size proportion ofcut tobacco under the Internet environment, The device adjusting size proportion of cut tobacco needs to be developed including a feeding belt conveyor, a tobacco regulating device, a discharging belt conveyor, a guiding groove and a fixed bracket. Among these devices the feeding belt conveyor adopts two-way control of size proportion ofcut tobacco without adjusting the choice; the device adjusting size proportion of cut tobacco consists of a feed roller of tobacco, a Uniform roller of tobacco and a Cut tobacco roller, mainly by adjusting the feeding roller of tobacco, Cut tobacco roller speed difference and gap adjustment to control size proportion cut tobacco. Application test was made in Henan tobacco corporation. The results showed that: the gap between the feeding roller and the broken roller are the significant factors in proportion of long stands rate, middle stands rate, short stands rate and small particles rate. the long stands rate is positively associated with the gap, the rest are negatively correlated with the gap, ② the rotational speed of cut tobacco smoothing roller, cut tobacco feeding roller, Cut tobacco cutting roller has certain effect on, proportion of long stands rate, middle stands rate, short stands rate and small particles rate and cannot be ignored in practical work. Conclusion: This design can improve the structure of the cut tobacco through the gap between the cut tobacco feed roller and the cut tobacco break roller. How to quantify the specific effect requires special research.

This paper is devoted to the primary spectro-polarimetric observation performed at the New Vacuum Solar Telescope of China since 2017, and our aim is to precisely evaluate the real polarimetric accuracy and sensitivity of this polarimetry by using full Stokes spectro-polarimetric observations of the photospheric line Fe I 532.4 nm. In the work, we briefly describe the salient characteristic of the NVST as a polarimeter in technology and then characterize its instrumental polarization based on the operation in 2017 and 2019. It is verified that the calibration method making use of the instrumental polarization calibration unit (ICU) is stable and credible. The calibration accuracy can reach up to 3$\times 10^{-3}$ . Based on the scientific observation of the NOAA 12645 on April 5th, 2017, we estimate that the residual cross-talk from Stokes $I$ to Stokes $Q$, $U$ and $V$, after the instrumental polarization calibration, is about 4$\times10^{-3}$ on average, which is consistent with the calibration accuracy and close to the photon noise. The polarimetric sensitivity (i.e., the detection limit) for polarized light is of the order of $10^{-3}$ with an integration time over 20 seconds. Slow modulation rate is indeed an issue for the present system. The present NVST polarimeter is expected to be integrated with an high-order adaptive optics system and a field scanner to realize 2D magnetic field vector measurements in the following instrumentation update., Comment: 17pages, 9 figures,accepted by Research in Astronomy and Astrophysics

Clarifying the interaction between active materials and current collectors of the same electrode is crucial for understanding the electrochemical energy storage mechanism and designing high-performance supercapacitors. The interaction mechanism is mainly due to the evolution of chemical bonding. Here, we explore the chemical bonding evolution between cobalt-nickel layered double hydroxide and carbon fiber paper by using ex situ x-ray photoelectron spectroscopy during redox reaction. The results reveal that chemical bonding corresponds to more ionic states at the lowest potential and more covalent states at the highest potential. Attributed to the formation of C-O-Metal (Co, Ni) chemical bonds, high capacitance with enhanced stability and rate capability is obtained. The Co-Ni layered double hydroxide electrode exhibits a high areal and mass specific capacitance of 0.55 and 952 F g-1 at a low mass loading of 0.58 mg cm-2. At a high mass loading of 3.59 mg cm-2, high areal and mass specific capacitance of 3.24 F cm-2 and 811 F g-1 are obtained. Based on this, a hybrid supercapacitor is fabricated with high-mass-loading Co-Ni layered double hydroxide and active carbon as positive and negative electrodes, respectively. As a result, this device delivers a prominent energy density of 20.9 Wh cm-3 at a power density of 0.12 W cm-3.

In past years, several hints of lepton flavor universality (LFU) violation have emerged from the and data. More recently, the Belle Collaboration has reported the first measurement of the longitudinal polarization fraction in the decay. Motivated by this intriguing result, along with the recent measurements of and polarization, we present the study of decays in supersymmetry (SUSY) with -parity violation (RPV). We consider , , and modes and focus on the branching ratios, LFU ratios, forward-backward asymmetries, polarizations of daughter hadrons, and the lepton. The RPV SUSY was capable of explaining the anomalies at the level, after taking into account various flavor constraints. In the allowed parameter space, the differential branching fractions and LFU ratios are largely enhanced by the SUSY effects, especially in the large dilepton invariant mass region. Moreover, a lower bound 10−6 is obtained. These observables could provide testable signatures at the high-luminosity LHC and SuperKEKB, and correlate with direct searches for SUSY.

Hydrogel scaffold is a popular cell delivery vehicle in tissue engineering and regenerative medicine due to its capability to encapsulate cells as well as its modifiable properties. However, the inherent submicron- or nano-sized polymer networks of conventional hydrogel will produce spatial constraints on cellular activities of encapsulated cells. In this study, we endeavor to develop an innovative cell encapsulatable cryogel (CECG) platform with interconnected macro-pores, by combining cell cryopreservation technique with cryogel preparation process. The hyaluronan (HA) CECG constructs are fabricated under the freezing conditions via UV photo-crosslinking of the HA methacrylate (HA-MA) that are dissolved in the 'freezing solvent', namely the phosphate buffered saline supplemented with dimethyl sulphoxide and fetal bovine serum. Two model cell types, chondrocytes and human mesenchymal stem cells (hMSCs), can be uniformly three-dimensionally encapsulated into HA CECG constructs with high cell viability, respectively. The macro-porous structures, generated from phase separation under freezing, endow HA CECG constructs with higher permeability and more living space for cell growth. The chondrocytes encapsulated in HA CECG possess enhanced proliferation and extracellular matrix secretion than those in conventional HA hydrogels. In addition, the HA-Gel CECG constructs, fabricated with HA-MA and gelatin methacrylate precursors, provide cell-adhesive interfaces to facilitate hMSCs attachment and proliferation. The results of this work may lay the foundation for us to explore the applications of the CECG-based scaffolds in the field of tissue engineering and regenerative medicine.

Nd content was varied in Nd 13.2 − x Fe 80.8 + x B6 (x = 0, 0.5, 1, and 1.5) to optimize the magnetic properties of sintered Nd–Fe–B/Tb–Fe–B composite magnets, which were prepared by mixing 9 g of Nd–Fe–B with 1 g of Tb17Fe75B8 powder. In conventional magnets, by reducing Nd content, the coercivity of 10.4 kOe in Nd13.2Fe80.8B6 decreases to 7.2 kOe in Nd12.2Fe81.8B6; meanwhile, in Nd–Fe–B/Tb–Fe–B magnets the coercivity does not decrease when reducing Nd content. In the intergranular phase, the Tb content increases owing to the reducing Nd content of the Nd–Fe–B alloy in the sintered composite magnets. Therefore, the excess Tb in Tb17Fe75B8 enters the intergranular phase, and more Tb atoms can substitute for Nd at the grain boundary of the Nd–Fe–B phase, leading to a more significant increase in coercivity. The remanence increases with reducing Nd content, and the energy product of 39.1 MGOe with a high coercivity of 21.0 kOe is obtained in Nd12.2Fe81.8B6/Tb17Fe75B8 magnets. These investigations show that magnetic properties can be further improved by regulating the element distribution in sintered composite magnets.

This paper provided an evaluation method to analyze the comfort interval of automobile seats. According to the theory and analytical procedure of interval parameter structure, based on the human pressure data and valuation results of a large number of automobile seat comfort subjective evaluation tests, the uncertain mathematical relations between objective data of automobile seat comfort test and subjective evaluation scores could be established. This mathematical relation was called interval relationship. The author established the seat evaluation database with a large number of test results, and developed an evaluation method of seat comfort interval with the application of the mathematical model. The Result of the analysis on the feasibility and effectiveness of the evaluation method proved that it could provide more reliable seat comfort evaluation results. The seat design engineer could use this method to replace the complex manual seat evaluation process. Meanwhile, the comfort score provided theoretical guidance for automobile seat design and improvement.

We study a particular version of the theory of cosmological $\alpha$-attractors with $\alpha=1/3$, in which both the dilaton (inflaton) field and the axion field are light during inflation. The kinetic terms in this theory originate from maximal $\mathcal{N}=4$ superconformal symmetry and from maximal $\mathcal{N}=8$ supergravity. We show that because of the underlying hyperbolic geometry of the moduli space in this theory, it exhibits double attractor behavior: their cosmological predictions are stable not only with respect to significant modifications of the dilaton potential, but also with respect to significant modifications of the axion potential: $n_s\simeq 1-{2\over N}$, $r\simeq {4\over N^2}$. We also show that the universality of predictions extends to other values of $\alpha \lesssim {\cal O}(1)$ with general two-field potentials that may or may not have an embedding in supergravity. Our results support the idea that inflation involving multiple, not stabilized, light fields on a hyperbolic manifold may be compatible with current observational constraints for a broad class of potentials., Comment: 26 pages, 9 figures; v2: published version with references added and discussion extended

A new solar telescope system is described, which has been operating at Huairou Solar Observing Station (HSOS), National Astronomical Observatories, Chinese Academy of Sciences (CAS), since the end of 2005. This instrument, the Solar Magnetism and Activity Telescope (SMAT), comprises two telescopes which respectively make measurements of full solar disk vector magnetic field and Hα observation. The core of the full solar disk video vector magnetograph is a birefringent filter with 0.1A bandpass, installed in the tele-centric optical system of the telescope. We present some preliminary observational results of the full solar disk vector magnetograms and Hα filtergrams obtained with this telescope system.

Micromachining of magnetic materials is becoming a crucial technology for future magnetic systems/devices such as high-density magnetic recording heads, high-density patterned media, magnetic quantum devices, and micro-magnetic smart systems. NiFe alloy, one of the typical ferromagnetic materials, can be deposited and fabricated using current thin film and micromachining technologies, and it has found various applications in microsensors, microactuators, and microsystems. In our recent work, Ni45Fe55 alloy with the highest saturation magnetic-flux density was selected as the micro-magnet for an all-silicon quantum computer. The micro-magnet was designed to create a large magnetic field gradient and to distinguish 29 Si nuclear spins arranged as chains in a 28 Si matrix with Larmor frequencies. This paper reports the micromachining of a Ni45Fe55 alloy mesa structure for an all-silicon quantum computer and the preliminary evaluation of its effectiveness using a magnetic force microscope (MFM) an da superconducting quantum interference device (SQUID). (Some figures in this article are in colour only in the electronic version)

Miniaturization of mechanical components is the simplest method to minimize thermo-mechanical noise in various kinds of resonating sensors and nano-electromechanical systems (NEMSs). As the dimensions of a structure shrink, surface effects tend to dominate the bulk properties in mechanical quality factors (Q-factors). This paper presents findings on nanomechanical properties of ultra-thin single-crystal silicon (SCS) resonators, with emphasis on their surface effects, resulting from thermal treatments and gas adsorption. The measured Q-factors were found to be very sensitive to the surface conditions. This implies that the surface-related mechanism, or adsorption-induced surface stress, should be considered to explain the observed behaviour. The results obtained in this study provide an insight into the understanding of effects of thermal treatments and gas adsorption on nanomechanics of resonating elements, and provide further proof that thermal treatment is an effective method to achieve higher Q-factors for future nanoengineered devices for ultimate sensing.

We analyze the magnetic configurations of three super active regions, NOAA 10484, 10486 and 10488, observed by the Huairou Multi-Channel Solar Tele- scope (MCST) from 2003 October 18 to November 4. Many energetic phenomena, such as flares (including a X-28 flare) and coronal mass ejections (CMEs), occurred during this period. We think that strong shear and fast emergence of magnetic flux are the main causes of these events. The question is also of great interest why these dramatic eruptions occurred so close together in the descending phase of the solar cycle.

In a Doppler broadened three-level Λ-type atomic system, we investigate the absorption spectrum of a weak probe laser in the presence of a saturating laser and a coupling laser. We find that, in order to observe coherent hole-burnings effectively, the two lower levels should be so well spaced that atomic collisions can be neglected, and the saturating (coupling) laser should counter-propagate (co-propagate) with the probe laser. We also give a qualitative analysis to understand the physical origin of coherent hole-burnings.

Tissue engineering (TE) is envisaged to play a vital role in improving quality of life by restoring, maintaining or enhancing tissue and organ functions. TE scaffolds that are two-dimensional in structure suffer from undesirable issues, such as pore blockage, and do not closely mimic the native extra-cellular matrix in tissues. Significant efforts have therefore been channeled to fabricate three-dimensional (3D) scaffolds using various techniques, especially electrospinning. In this study, we propose a modified one-step electrospinning process to arrive at a 3D scaffold with highly interconnected pores. Using a blend of poly (L-lactide)/polycaprolactone/poly (ethylene oxide), this mechanically viable, sponge-like 3D scaffold exhibited sufficiently large pores and enabled cell penetration beyond 500 μm. Dexamethasone (Dex) was loaded into the fibers and a sustained drug release was achieved. Further, the potential of this Dex-loaded 3D scaffold was evaluated for upregulation of osteogenic genes with mesenchymal stem cells. The as-produced Dex-loaded 3D scaffold possesses a unique intertwined sub-micron fibrous morphology that can be tailored for use in bone tissue engineering and beyond. MOE (Min. of Education, S’pore) Accepted version