Soft Landing Research Articles

A Study on the Financial Situation Changes of Major A-share Real Estate Companies Since the Adjustment of Purchase Restriction Policies

To prevent over expansion of property bubbles in China, housing purchase restriction policies were put into effect in 2010. Nevertheless, to be adaptable to economic conditions at that time, there was firstly a relaxation of housing purchase restriction policies in 2014 and after that, several more adjustments were made. By analyzing the financial indicators of the main real estate enterprises in A-share market, this paper wants to find the general trends and common features of those corporations under policy adjustments and changeable market environment. The analysis results show that the majority of firms kept high levels of debt and inventory all the time and from 2014 to 2019, most companies net income margins, net income and operation revenue generally kept increasing. However, as the Coronavirus pandemic broke out at the end of 2019, those profitability measures started to decrease widely and sequentially, even with a new round of policy easing. Facing with this situation, it is suggested that to prevent debt risks, property enterprises could take deleveraging and destocking into consideration and to achieve a soft landing of the housing market, new ways of policy adjustment could be implemented by the government.

Study on the soft-landing of large inertia valve based on multi-objective optimization of annular gap

Variable valve mechanism and its technology are widely used in vehicle diesel engines. As a critical component, the performance of reciprocating actuator is the guarantee for the realization of electro-hydraulic variable valve. In order to solve the problem of high setting speed in electro-hydraulic camless variable valve system, a variable valve actuator based on annular gap buffer is proposed and optimized to realize quick closing and soft landing. The experimental results show that the actuator can achieve the purpose of setting buffer, and the setting speed is 0.5 m/s with 15 ms of closing time. AMESim is used to build the system simulation model and calibrated by experiments. The simulated lift curve is close to the experimental curve, and its Pearson coefficient is 0.9995. The influence of structural parameters on the system driving ability and buffering effect is studied through the model. According to the simulation results, the annular gap eccentricity will affect the buffering effect. When the eccentricity increases from 0.005 to 0.035 mm, the landing velocity increases by 0.1 m/s and the valve closing time decreases by 0.9 ms. NSGA-II method is used to optimize the structural parameters of the annular gap, and an obvious Pareto front is obtained and the optimal solution is applied in next experiments. The landing speed is reduced from 0.5 to 0.25 m/s, and the landing time is still less than 15 ms. This paper provides a simple cushioning scheme for electro-hydraulic camless variable valve soft landing which is independent of proportional valve.

ASSET PRICING RESEARCH FOR BEGINNERS: SURVEY OF PROMINENT RESEARCH ON STOCK RETURNS AND RETURN DETERMINANTS

Over the last five decades, business academics have identified over three hundred factors that influence stock returns. A newcomer to this field might be overwhelmed by the amount of research and the nature of it - sometimes confusing, even conflicting at times. This paper tries to hand hold a beginner and gently introduce him to the high seas of asset pricing – especially research that focuses on stock returns & potential return determinants. We have tried to cover leading research that will provide a soft landing for the beginner to the field of asset pricing. With this introduction, we hope that the newcomer will find it easier to navigate her/his way confidently to her/his research interest.

Variable stiffness design for the soft landing of a 2016HO3 asteroid probe

China plans to launch a probe to detect and sampling on the near-Earth asteroid 2016HO3 around 2025. In view of this, this paper discusses an alternative landing strategy with passive variable stiffness landing gears, which help to land the probe stably on the asteroid for sufficient sampling time. First, a three-legged lander is introduced, following which, a four-bar-linkage-based variable stiffness leg is designed considering the design constraint of landing clearance. Then, a numerical model of the probe for landing simulation is established. Moreover, a surrogate model is obtained using the second-order response surface method (RSM) to improve computational efficiency. Based on the surrogate, the variable stiffness leg and the pressing force are optimized to reduce the impact forces at touchdown and the landing time. Finally, the optimal solution is validated using the dynamics analysis model.

Multi-pursuer pursuit differential game for an infinite system of second order differential equations

We study a pursuit differential game of many pursuers and one evader. The game is described by the infinite systems of $m$ inertial equations. By definition, pursuit in the game is completed if the state and its derivative of one of the systems are equal to zero at some time. In the literature, such a condition of completion of pursuit is also called soft landing. We obtain a condition in terms of energies of players which is sufficient for completion of pursuit in the game. The pursuit strategies are also constructed.

Cryo-EM of soft-landed β-galactosidase: Gas-phase and native structures are remarkably similar.

Native mass spectrometry (MS) has become widely accepted in structural biology, providing information on stoichiometry, interactions, homogeneity, and shape of protein complexes. Yet, the fundamental assumption that proteins inside the mass spectrometer retain a structure faithful to native proteins in solution remains a matter of intense debate. Here, we reveal the gas-phase structure of β-galactosidase using single-particle cryo-electron microscopy (cryo-EM) down to 2.6-Å resolution, enabled by soft landing of mass-selected protein complexes onto cold transmission electron microscopy (TEM) grids followed by in situ ice coating. We find that large parts of the secondary and tertiary structure are retained from the solution. Dehydration-driven subunit reorientation leads to consistent compaction in the gas phase. By providing a direct link between high-resolution imaging and the capability to handle and select protein complexes that behave problematically in conventional sample preparation, the approach has the potential to expand the scope of both native mass spectrometry and cryo-EM.

Cues to land softly and quietly result in acute reductions in ground reaction force loading rates in runners

BackgroundA common gait retraining goal for runners is reducing vertical ground reaction force (GRF) loading rates (LRs), which have been associated with injury. Many gait retraining programs prioritize an internal focus of attention, despite evidence supporting an external focus of attention when a specific outcome is desired (e.g., LR reduction). Research QuestionDoes an external focus of attention (using cues for quiet, soft landings) result in comparable reductions in LRs to those achieved using a common internal focus (forefoot striking while barefoot)? MethodsThis observational study included 37 injured runners (18 male; mean age 36 (14) years) at the OMITTED Running Center. Runners wore inertial measurement units over the distal-medial tibia while running on an instrumented treadmill at a self-selected speed. Data were collected for three conditions: 1) Shod-Control (wearing shoes, without cues); 2) Shod-Quiet (wearing shoes, cues for quiet, soft landings); and 3) Barefoot-FFS (barefoot, cues for forefoot strike (FFS)). Within-subject variables were compared across conditions: vertical instantaneous loading rate (LR, primary outcome); vertical stiffness during initial loading; peak vertical GRF; peak vertical tibial acceleration (TA); and cadence. ResultsVertical LR, stiffness, and TA were lower in the Shod-Quiet compared to Shod-Control p < 0.001). Peak vertical GRF and cadence were not different between Shod-Quiet and Shod-Control. Reductions in stiffness and LR were similar between Shod-Quiet and Barefoot-FFS, and GRF in Barefoot-FFS remained similar to both shod conditions. However, runners demonstrated additional reductions in TA and increased cadence when transitioning from Shod-Quiet to the Barefoot-FFS condition (p < 0.05). SignificanceThese results suggests that a focus on quiet, soft landings may be an effective gait retraining method for future research.

Robust adaptive control of underwater glider for bottom sitting-oriented soft landing

This paper deals with the formalization, design, theorization, and implementation of a robust adaptive nonlinear control scheme to solve the bottom sitting-oriented soft landing control problem for an underwater glider under model uncertainties, actuator dynamics, and external disturbances. First, uniformized motion equations are derived based on Lie derivatives for describing pitch angle and vertical velocity tracking control. Then, the robust adaptive control framework is enhanced by containing an anti-windup auxiliary system and a disturbance observer. The stability of the closed-loop control system based on Lyapunov theory is proven to guarantee the boundedness of the entire internal signals. Finally, multifarious experimental results are also conducted by a self-developed underwater glider to demonstrate the effectiveness of the proposed controller.

Spontaneous ligand loss by soft landed [Ni(bpy)3]2+ ions on perfluorinated self-assembled monolayer surfaces.

Transition metal (TM) complexes are widely used in catalysis, photochemical energy conversion, and sensing. Understanding factors that affect ligand loss from TM complexes at interfaces is important both for generating catalytically-active undercoordinated TM complexes and for controlling the degradation pathways of photosensitizers and photoredox catalysts. Herein, we demonstrate that well-defined TM complexes prepared on surfaces using ion soft landing undergo substantial structural rearrangements resulting in ligand loss and formation of both stable and reactive undercoordinated species. We employ nickel bipyridine (Ni-bpy) cations as a model system and explore their structural reorganization on surfaces using a combination of experimental and computational approaches. The controlled preparation of surface layers by mass-selected deposition of [Ni(bpy)3]2+ cations provides insights into the chemical reactivity of these species on surfaces. Both surface characterization using mass spectrometry and electronic structure calculations using density functional theory (DFT) indicate that [Ni(bpy)3]2+ undergoes a substantial geometry distortion on surfaces in comparison with its gas-phase structure. This distortion reduces the ligand binding energy and facilitates the formation of the undercoordinated [Ni(bpy)2]2+. Additionally, charge reduction by the soft landed [Ni(bpy)3]2+ facilitates ligand loss. We observe that ligand loss is inhibited by co-depositing [Ni(bpy)3]2+ with a stable anion such as closo-dodecaborate dianion, [B12F12]2-. The strong electrostatic interaction between [Ni(bpy)3]2+ and [B12F12]2- diminishes the distortion of the cation due to interactions with the surface. This interaction stabilizes the soft landed cation by reducing the extent of charge reduction and its structural reorganization. Overall, this study shows the intricate interplay of charge state, ion surface interactions, and stabilization by counterions on the structure and reactivity of metal complexes on surfaces. The combined experimental and computational approach used in this study offers detailed insights into factors that affect the integrity and stability of active species relevant to energy production and catalysis.

Feature Article: A soft landing may be in sight, but expect turbulence

Feature Article: A soft landing may be in sight, but expect turbulence

Trajectory Planning for Jumping and Soft Landing With a New Wheeled Bipedal Robot

Trajectory Planning for Jumping and Soft Landing With a New Wheeled Bipedal Robot

Product Soft Landing of Experience Products and the Role of Pre-release Advertising Responsiveness

Product Soft Landing of Experience Products and the Role of Pre-release Advertising Responsiveness

정책논변모형을 통한 고교학점제 담론 분석

This study analyzes the discourse through the policy argument model and proposes implications for policy implementation under the recognition that the policy means and contents are important for the correct implementation of the policy purpose of the high school credit system. To achieve the research purpose, this study reorganized and utilized Toulmin et al.’s (1979) analysis framework.The conclusions of the analysis using the policy argument model are as follows. First of all, since the high school credit system is an education policy that requires public consensus in consideration of its linkage with university entrance examinations, it is necessary to solidify the foundation for a soft landing sequentially through the process of social consensus and public discussion. Next, we need to move away from the tendency to take a piecemeal approach to the issues of the high school credit system’s curriculum, teaching and learning, educational evaluation, and teachers and facilities, and move toward the holistic approach. There needs to be a soft landing for unit schools with an organic approach. As suggested in the argumentative analysis of this study, it seems necessary to have a strategy that can comprehensively enhance the technical feasibility and political feasibility.

Creating wetland islands to enhance shoreline habitat for fish recruitment in a modified shallow lake

Abstract Soft shoreline engineering is increasingly used to combine shoreline fortification with the enhancement of biodiversity and biological production of land–water transitions. From 2016 to 2021, the large‐scale ecosystem restoration project Marker Wadden has created new multiple wetland islands from local sediments in the highly modified Lake Markermeer, the Netherlands. Instead of replacing steep rip‐rap shorelines with soft shorelines, new islands with soft land–water transitions were engineered to offset the marked declines in bird and fish populations in this Natura 2000 area, protected under the European Union Birds and Habitats Directives. This new approach was evaluated by assessing the added value of the newly created wetland islands with soft shorelines to the existing steep rip‐rap fortified shores of the lake, for the enhancement of fish spawning and nursery habitat. Young‐of‐the‐year fish densities at the Marker Wadden islands were highest in sheltered bays and wetlands with nutrient‐rich silt sediments, and lowest at wind‐exposed sandy beaches. Both newly engineered soft shorelines and existing rip‐rap shorelines contributed to habitat diversity, although fish densities declined considerably with increasing exposure to wind‐induced wave power. Building soft shorelines as a new archipelago instead of replacing existing shoreline habitats increased the total length of the land–water transitions in the lake. The 800 ha Marker Wadden archipelago covers only 1% of the 70,000 ha lake surface area, but provides a 16% increase in shoreline habitat and a fivefold increase in soft shoreline for the lake. We conclude that designing wetland islands as a means of lake restoration can contribute effectively to sheltered habitat enhancement for fish spawning and nurseries, and thereby to the potential conservation of fish communities. The approach of building islands achieves this without compromising the complementary functionality of the original, more mature, shorelines of the lake.

Flame structure of GCH4/GOX pintle model combustor with wall confinement

The pintle injector is a representative option for designing a throttleable rocket engine that can be applied for various applications, including the vertical soft landing of reusable launch vehicles. Although the most direct research method to investigate the characteristics of pintle injectors experimentally is the high-pressure combustion test, it is often limited due to its cost and operational hazards. Consequently, atmospheric combustion or cold flow tests are frequently applied in the rocket injector field to simulate and study the fundamental combustion or spray characteristics. However, previous works, including such simulated experiments under atmospheric conditions, involved an unrealistically wide combustor or open condition. Since only a single pintle injector is typically used per engine, the combustor wall may significantly influence the fundamental characteristics. Thus, in this study, a pintle injector combustor with adequate wall confinement is designed, and its flame structure is investigated across a wide range of total volume flow rates and mixture ratio conditions, incorporating several geometries with varying gaseous oxygen injection areas. This research primarily focuses on the flame structure and its angle. Under specific experimental conditions, the unreported unstable flame was newly observed. The overall experimental results, supported by numerical methods, indicate that wall confinement has substantial importance in simulating a realistic flame structure and internal flow field within the combustor.

Highly conductive p-type nc-SiOX:H thin films deposited at 130°C via efficient incorporation of plasma synthesized silicon nanocrystals and their application in SHJ solar cells

We present highly conductive and transparent p-type hydrogenated nanocrystalline silicon oxide (p-type nc-SiOX:H) layers produced by Plasma Enhanced Chemical Vapor Deposition (PECVD) at 130°C and 150°C. We report on the crystalline volume fraction (XC), spectral broadening parameter C, and dark conductivity (σ) as functions of the growth temperature and RF power, and how these properties evolve with post-deposition annealing at 250°C and 300°C. Interestingly, we observe that the best layers in terms of crystalline volume fraction and conductivity are obtained at the lowest temperature and RF power, which we attribute to the soft landing of silicon nanocrystals synthesized in the plasma. The p-type nc-SiOX:H layers with the best properties on glass substrates are implemented as carrier-selective contacts in silicon heterojunction (SHJ) solar cells with the structure: (n) a-Si:H / (i) a-Si:H / n-type c-Si / (i) a-Si:H / (i) a-SiOX:H / (p) nc-SiOX:H / (p) nc-Si:H where all films are deposited by PECVD. The cells were completed with sputtered ITO on the front and rear sides plus Ag on the rear side, and Ag grid on the front, with the best devices showing conversion efficiencies of 21.8%, which, contrary to a-Si:H contact layers, are preserved or even slightly improved upon annealing at 240°C.

An Audio-Based Iterative Controller for Soft Landing of Electromechanical Relays

An Audio-Based Iterative Controller for Soft Landing of Electromechanical Relays

Analysis of the Internet Reviews of The Wandering Earth 2 in China and America Based on Hofstede's Cultural Dimensions

Films are carriers of a countrys culture, thus building a powerful film country is to build a strong cultural country. In this context, ensuring the smooth sailing of Chinese films is of great significance. Taking The Wandering Earth 2 as an example, this research builds a cultural dimensional model of films communication effects under Hofstedes cultural dimensions. Based on a self-built corpus of reviews which contains 200 most heated comments from the Internet Movie Database (IMDb) and Douban, the research applies an original codebook consisting of 12 two grade indicators to rationalize audience cultural sensing. It is found that the sensing of Chinese viewers on the four dimensions averagely higher than the ones of American viewers, while the long-term orientation provides a possible common ground in both sides. The differences in the audiences internet reviews of The Wandering Earth 2 give a clue to the needs of soft landing, hard core and human touch, which Chinese films should well adopt as the key capabilities in cross-cultural diffusion.

Reinforcement learning-based stable jump control method for asteroid-exploration quadruped robots

Unlike the spherical gravitational field of planets and other large solar system bodies, the gravitational field of asteroids is irregular and weak. It is challenging for a planetary rover to obtain sufficient traction forces in this environment. However, this gravitational environment is suitable for legged robots with jumping ability, but it also imposes higher demands on control methods. Therefore, this study aimed to address the problem of jump control method for asteroid-exploration quadruped robots. As the robot jumps off the surface of an asteroid, it would fly for a certain amount of time because of the low gravitational acceleration. The prolonged flight phase underscores the significance of the robot's take off and attitude control. A model-free stable jumping control method was devised in this study. This method can satisfy the control requirements for takeoff, attitude adjustment, and soft landing by using end-to-end multi-agent reinforcement learning (MARL). MARL is more advantageous than single-agent reinforcement learning in dealing with composite motion control problems under similar observation conditions. A simulated training environment was established, incorporating models of the gravitational field, task partitioning for jumping, and design of reward functions, including jump trajectory planning. The efficacy of the proposed jump control method for a quadruped robot was successfully demonstrated in the gravitational environment of an irregular rod-shaped asteroid, 216 Kleopatra.

Unraveling the Molecular Dynamics of Glucose Oxidase Desorption Induced by Argon Cluster Collision.

The bombardment of a protein multilayer target by an energetic argon cluster ion beam enables protein transfer onto a collector in the vacuum while preserving their bioactivity (iBEAM method). In parallel to this new soft-landing variant, protein transfer in the gas phase is a prerequisite for their characterization by mass spectrometry. The successful transfer of bioactive lysozymes (14 kDa) by cluster-induced soft landing and its mechanistic explanation by molecular dynamics (MD) simulations have sparked an important inquiry: Can heavier biomolecules be desorbed while maintaining their tridimensional structure and hence their bioactivity? To address this question, we employed MD simulations using a reactive force field (ReaxFF). Specifically, the Ar cluster-induced desorption of glucose oxidase from either a gold substrate or a lysozyme underlayer was modeled using the LAMMPS code. First, the force field parameters were trained by computing the dissociation energetics of a series of organic molecules with ReaxFF and DFT, in order to realistically describe N-S and O-S interactions in the bombarded glucose oxidase molecule. Second, bombardment simulations investigated the effects of cluster size (ranging from 1000 to 10000 Ar atoms) and kinetic energy (1.5 and 3.0 eV/atom) on the structural features and energetics of the desorbing glucose oxidase. Our results show that large argon clusters (≥7000) are needed to desorb glucose oxidase from a gold surface, yet protein fragmentation and/or pronounced denaturation occur. However, the transfer of structurally preserved glucose oxidase in the gas phase is predicted by the simulations when an organic layer is used as a substrate.