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Ecosystem services are closely related to human well-being, and the study of the trade-offs and synergies between ecosystem services is currently a pressing research topic. By analyzing its conceptual connotation and research characteristics, we can better understand the relationship between the regional ecosystem services, adapt to the need of the parties to maximize the overall benefits, and provide a basis for decision-making for regional development. This study focused on the literature quantitative characteristics of domestic and foreign research on ecosystem services trade-offs and synergies from 1996 to 2020 by literature analysis and comparative analysis. Domestic and foreign research themes from different periods, from the beginning of development to the present, were analyzed. The conceptual connotation and research characteristics of the trade-offs and synergies of ecosystem services were summarized. Finally, shortcomings existing in current research and future research directions were identified. The specific conclusions are as follows: the number of domestic and foreign studies is increasing, with the foreign growth rate faster than domestic; Ecosystem service trade-offs and synergies are strongly dependent on time and space scales, the difference of spatio-temporal scale jointly drives the dynamic change of the relationship between trade-offs and synergies, but there is still a lot of research space in this field. In the future, it is necessary to strengthen the research on the framework model, quantitative analysis, driving mechanism, internal mechanism, threshold effect, supply and demand of temporal and spatial changes to better understand the mechanism of temporal and spatial changes in ecosystem service trade-offs and synergies, and achieve a mutually beneficial situation for regional ecological environment and socioeconomic development.

Dissimilar joint between low alloy steel 16Mn and 304L austenitic stainless steel was welded in the air and under water with two different flux-cored wires: commercially obtained ER308 filler and specially developed nickel-based tubular wire. For microstructure comparison, dissimilar welded joints in the air and under water were acquired at the same welding procedures. The effect of water environment on microstructure, alloying elements distribution and microhardness profiles of dissimilar welded joints was discussed. The results show that typeⅡ boundary existed between austenitic weld metal and ferritic base metal in underwater welds similar to that in the air welds. The underwater Ni-based welds had a lower dendritic spacing than air welds. The amount of delta-ferrite present in underwater welds with ER308 filler was more than that in air welds because of the higher cooling rate in water environment. Major alloying elements were non-uniformly distributed along the austenitic weld metal/16Mn interface. Macroscopic composition gradients did not tend to form in air welds because of high heat input. Maximum microhardness value of 470 HV in wet welded joints was found in coarse-grained heat affected zone instead of transition zone. The transition zone at 16Mn side of underwater austenitic stainless steel welded joints exhibited high microhardness of 330 HV, which was strongly diluted by ferritic base metal.

A double-module semi-submersible platform for scientific experiment has been applied firstly in practical engineering. Hinge-type connectors are used to link the two modules reliably and release the relative pitch freedom, and the strength of connector structures determines directly the integrity and safety of the platform. In this paper, the three-dimensional finite element model of the platform structure is developed including the local features of connectors, and main elastic modes are obtained. By using the Potential flow theory and the Green Function method, the hydrodynamic coefficients of the model are determined. Based on the three-dimensional hydroelastic theory, the response amplitude operators (RAOs) of generalized coordinates associated with different order modes are investigated. That indicates the structural deformation of connectors is excited mainly by modes of horizontal bending moment and torsion, and the stress responses in the longitudinal bulkheads close to bearings are generally marked. Using the modal superposition method, the RAOs of stress in the typical joints of connector structures are calculated under the given wave directions. Considering the JONSWAP spectrum and the amplitudes of stress responses of connector structures following Rayleigh distribution in short term, the strength of the connector structure is predicted in short term. In order to verify the correctness of the strength prediction method presented in this paper, more than thirty stress sensors are installed on the typical joints of connector structures of the double-module semi-submersible platform located in the real sea. Those stress responses are monitored during the typical typhoon activity, and the statistical data is compared with the predicted results from the theoretical model. Both the distribution trend and magnitudes of the results from the two methods are principally consistent that validates the given model. This theoretical method may provide an effective tool to analyze the strength of connector structures of multiple-module offshore platform.

This study focuses on saturated inference of low-energy laser on the thermal imager and quantitatively analyzes laser power densities and the corresponding saturated laser spots at different incident angles by taking into account the effects of interference laser, atmospheric turbulence, the lens and the photoelectric detector. The relative position of the laser spot on the photosensitive surface on the detector of the thermal imager from the target image is adopted as the evaluation index of laser-induced saturated interference effect. According to the present results, at an incident angle of 0, the target image is partly or completely covered by the interference laser spot, with obvious interference effect and low required laser power. As the incident angle increases, the interference effect is significantly affected and the interference effect is lower than the condition at an incident angle of zero. The interference can be achieved by controlling both size and position of the laser spot.

A 9-DOF hydraulic drilling robot is introduced. It is developed to direct at low efficiency of traditional tunnel segment drilling, and single operation capacity and low automation of existing drilling equipment. Virtual joint is introduced, and kinematics model of robot is established by combining D-H (Denavit-Hartenberg) parameter table to analyze forward and inverse kinematics of robot. Based on optimization of hole position accuracy, inverse kinematics is processed by engineering, unique inverse kinematics solution is obtained, and corresponding algorithm is programmed to control robot movement to realize automatic drilling. The real machine test verification is carried out in simulated tunnel environment. The test results show that the developed robot can meet the size requirements of various types of installation holes in 34 different tunnels, can adjust its own posture intelligently along the track, with accuracy of drilling position less than 10 mm, and has the ability of automatic tunnel drilling. [ABSTRACT FROM AUTHOR]

The cyclotron is designed as the injector of the Heavy Ion Medical Machine (HIMM) in Wuwei city, China. It provides 10 uA carbon beams to fulfill the requirement of the accumulation in the following syn-chrotron. The Radial detector is used to measure the beam current and beam turn motion in this Cyclotron. The beam current signal gathered by radial detector is acquired by four picoammeters, meanwhile the beam time structure is measured with FPGA and real time operating system. This paper introduces the design of radial detector, the motion control and data acquisition system for it of the cyclotron. Finally, the beam current and turn pattern measurement results at HIMM are presented in this paper., Proceedings of the 7\textsuperscript{th} Int. Beam Instrumentation Conf., IBIC2018, Shanghai, China