Introduction and Prospects of Gravity-1 Launch Vehicle’s Sea-Based Three Verticals Testing and Launch Mode

Gravity-1 was the world's first carrier rocket to adopt the sea-based “three vertical” testing launch mode. This article introduces the overall layout of the launch site and the workflow of rocket testing and launch for its maiden flight mission. The process of vertical assembly, vertical testing, vertical transportation, and sea-based hot launches are explained. Additionally, it provides an outlook on the improved “three vertical” testing and launch mode for future missions, such as land-based launches, rapid launches, and remote sea launches.

2 K superfluid helium cryogenic vertical test system for superconducting cavity of ADS Injector I

Purpose The accelerator-driven subcritical system(ADS)is the internationally recognized key technology of nuclear waste problem treatment,of which superconducting proton linac is an important part.With the support of the strategic science and technology pilot project of the Chinese Academy of Sciences,the Institute of High Energy Physics of the Chinese Academy of Sciences took the lead in the research of 325 MHz superconducting proton linac,which is called ADS Injector I.The superconducting accelerator part of ADS Injector I mainly consists of 14 spoke-type superconducting cavities withβ0.12.At the same time,the research work of various cavities with differentβvalues and different frequencies is also carried out to lay the technical and technological foundation for ADS main accelerator.The only way to determine whether the superconducting cavity can reach the design target and whether it can be installed into the cryostat is the vertical test at cryogenic.As the only way to test the microwave performance of the superconducting cavity at low temperature,the vertical test can accurately test the acceleration gradient Eacc and the corresponding quality factor Q0 of the superconducting cavity.The design and construction of the superconducting cavity vertical test facility is based on the practical needs of the pilot project and the long-term development of the superconducting accelerator.Methods This paper mainly introduces the design and construction of the cryogenic vertical test system for the superconducting cavity of ADS Injector I,including the system scheme design,process design,heat load analysis,2 K superfluid helium obtaining method,system commissioning and operation,etc.Results and Conclusion The static heat leakage at 2 K of the 2 K superfluid helium vertical test system of ADS Injector I is 1.624W,which has reached the international advanced level.The 2 K superfluid helium vertical test system of ADS Injector I after constructed not only meets the test requirements of ADS pilot project,but also conducts 4 K and 2 K vertical tests for other different types of superconducting cavities and relevant cryogenic experiments.

A vertical test system for China-ADS project injector Ⅱ superconducting cavities

To test superconducting cavities, a vertical test system has been designed and set up at the Institute of Modern Physics （IMP）. The system design is based on VCO-PLL hardware and the NI Labview software. The test of the HWR010#2 superconducting cavity shows that the function of this test system is satisfactory for testing the low frequency cavity.

Study on the Multi-Component Test Technology of Solid Rocket Motors

This paper presents a calculation method, and composition of a five-component force test device, to resolve the requirement for solid rocket motor multi-component force test. It compares the difference between two classical algorithms, and summarizes the structure and practical usage of the solid rocket motor multi-component force using soft connection structure measurement. The decoupling method of test data is described, and a reasonable research method for solid rocket motor multi-component force is also given in this paper.

Ultrahigh accelerating gradient and quality factor of CEPC 650 MHz superconducting radio-frequency cavity

Two 650 MHz single-cell superconducting radio-frequency(SRF)cavities used for the Circular Electron Positron Collider(CEPC)were studied to achieve a high accelerating gradient(E_(acc))and high intrinsic quality factor(Q_(0)).The 650 MHz single-cell cavities were subjected to a combination of buffered chemical polishing(BCP)and electropolishing(EP),and their E_(acc) exceeded40 MV/m.Such a high E_(acc) may result from the cold EP with more uniform removal.BCP is easy,cheap,and rough,whereas EP is complicated,expensive,and precise Therefore,the combination of BCP and EP investigated in this study is suitable for surface treatments of mass SRF cavities.Medium temperature(mid-T)furnace baking was also conducted,which demonstrated an ultrahigh Q_(0) of 8×10^(10) at 22 MV/m for both cavities,and an extremely low BCS resistance(R_(BCS))of~1.0 nΩwas achieved a2.0 K.

Validity and reliability of three methods of stiffness assessment

Background：Stiffness is commonly assessed in relation to injury and athletic performance.The purpose of this research was to compare the validity and reliability of 3 in vivo methods of stiffness assessment using 1 cohort of participants.Methods：To determine inter-day reliability,15 female netballers were assessed for stiffness twice within 1 week using unilateral hopping（vertical stiffness）,free oscillations of the calf,and myometry of various muscles of the triceps surae.To establish convergent construct validity,stiffness was compared to static and dynamic strength measurements.Results：Test–retest stiffness results revealed that vertical stiffness produced moderate to high reliability results and myometry presented moderate to very high reliability.In contrast,the free oscillation technique displayed low to moderate reliability.Vertical stiffness demonstrated a significa t correlation with rate of force development during a squat jump,whilst myometer stiffness measurements from 3 sites in the lower limb revealed significan correlations with isometric rate of force development.Further,significan negative correlations were evident between the eccentric utilisation ratio and various myometer stiffness results.No relationships were established between the free oscillation technique and any of the performance measurements.Conclusion：These results suggest that vertical stiffness and myometry are valid and reliable methods for assessing stiffness.

The flame retardancy of alginate/flame retardant viscose fibers investigated by vertical burning test and cone calorimeter

In this research, the flame retardancy of neat alginate fiber, flame retardant viscose fiber （FRV） and alginate/FRV （50/50） blending fibers were investigated by vertical burning and cone calorimeter tests. The vertical burning test showed that the afterflame time of alginate fiber was 0 s, but alginate presented serious smoldering behavior with the afterglow time of 605 s and damaged length of 85 mm, while the afterglow time of FRV was 0 s. When the FRV was incorporated into alginate with the weight ratio of 50/ 50, the afterglow time and damaged length were significantly reduced to 85 s and 35 mm, indicating the smoldering of alginate can be effectively decreased. The morphology and chemical structure of the alginate residual demonstrated that it was seriously destroyed during smoldering process, which was ascribed to its relative low initial thermal degradation temperature. Based on the thermal properties analysis, alginate and FRV fibers shared the concurrence of rapid degradation in the same temperature region of 250-300 ℃, through which, the compact and stable char formed by FRV can prevent the heat transmission and suppress the smoldering of alginate. Further, the cone calorimeter results demonstrated that the time to ignition （TTI） significantly increased and peak heat release rate （PHRR） decreased for alginate/FRV （50/50） compared with FRV. With this research, a new method to overcome the smoldering of alginate was proposed by blending with FRV

Design of a 325 MHz half wave resonator prototype at IHEP

A 325 MHzβ=0.14 superconducting half-wave resonator prototype has been developed at the Institute of High Energy Physics, Beijing, which can be applied in the low energy section of continuous wave high current proton linear accelerators. The electromagnetic design, multipacting simulation, mechanical optimization and fabrication are introduced in detail. Test results at room temperature and 4.2 K, and a comparison between measured and simulated results, are analyzed in this paper.

Studies of an LL-type 500 MHz 5-cell superconducting cavity at SINAP

A low loss- （LL） type 500 MHz 5-cell superconducting niobium prototype cavity with a large beam aperture has been developed successfully including the optimization, the deep drawing and electron beam welding, the surface treatment and the vertical testing. The performance of the fundamental mode was optimized and the higher order modes were damped by adopting an enlarged beam pipe for propagation. Surface preparation or treatment including mechanical polishing, buffered chemical polishing and high pressure rinsing with ultra-pure water and so on was carried out carefully to ensure a perfect inner surface condition. The vertical testing results show that the accelerating voltage higher than 7.5 MV was obtained while the quality factor was better than 1× 109 at 4.2 K. No obvious multipacting or field emission was found during the test. However, a quench happened while increasing the field a little higher than 7.5 MV that at present limited the cavity performance.

Field measurement for superconducting magnets of ADS injector Ⅰ

A superconducting magnet prototype for Accelerator Driven Sub-critical System Injection- I had been designed and fabricated, and tested in a new made vertical Dewar in November 2012. Batch magnet production was processed after some major revision from the magnet prototype, they include： removing off the perm-alloy shield, extending the iron yoke, using thin superconducting wire, etc. The first one of the batch magnets was tested in the vertical Dewar at the Harbin Institute of Technologyin in September 2013. A field measurement was carried out at the same time by the measurement platform that was seated on the top of the vertical Dewar, the measurement results met the design requirements. This paper will present the field measurement system design, measurement results and discussion on the residual field from the persistent current effect.

Themagnetic field measurement system for HEPS-TF superconducting wiggler

Background High Energy Photon Source(HEPS)is the fourth-generation synchrotron radiation source to be established in China.HEPS is a high-performance and high-energy synchrotron radiation light source with a beam energy of 6 GeV and an ultra-low emittance of better than 0.06 nm×rad(http://english.ihep.cas.cn/heps/index.html).Superconducting 3W1 wiggler magnet is one of the insertion devices in High Energy Photon Source Test Facility project(HEPS-TF).And it is also the key component to obtain higher brightness in high photon energy range.Purpose In the development process of superconducting wiggler,in order to ensure the magnetic field quality of each processing,it is necessary to monitor the magnetic field performance of before and after the full length bare magnet installed with cryostat.Therefore,different magnetic field measuring devices are being developed for different develop stages.Methods The magnetic field performance of the full length bare magnet should be tested in vertical at low temperature.After the magnetic structure is installed in the horizontal cryostat,the horizontal test is carried out.In view of these two processes,the vertical magnetic field measurement system and the horizontal magnetic field measurement system have been developed,respectively.Results The magnetic performances of the full length bare magnet and assembled with the horizontal cryostat were measured by the vertical and horizontal magnetic field measurement system.The first and second field integrals are corrected to better than the Physical requirements according to the magnetic field measurement results.Detailed magnetic field performances are described in this paper.Conclusion After more than a year operation of 3W1-SCW on the BII line station,the characteristic energy and photon flux of synchrotron radiation have been greatly improved,and the performance is excellent.It indicates that the measurement results of the magnetic field measurement system are reliable and credible.

Physical design of superconducting magnet for ADS injection Ⅰ

A superconducting solenoid prototype magnet for Accelerator Driven Snbcritical System（ADS） Injection I has been designed and fabricated,which has also been tested in a liquid Helium state inside a vertical Dewar in the Haerbin institute of Technology in November 2012.The design current was 210 A.when the test current reached400 A no quench occurred so the solenoid magnet was forced to quench by the embedded heaters.The integral field strength,leakage held at the nearby upstream and downstream superconducting spoke cavities all meet the design requirements.At the same time,it also checked the reliability of the vertical test Dewar and the quenched detection system.The superconducting prototype magnet has accumulated valuable experiences for the coming batch magnets production and cryogenic test.

Ignition-Proof Properties of a High-Strength Mg-Gd-Ag-Zr Alloy

A high-strength Mg-15.3Gd-l.8Ag-0.3Zr （GQ152K, mass fraction） alloy was prepared by conventional ingot metallurgy process. The solution and aging （denoted as T6） treated alloy exhibits remarkable mechanical properties with ultimate tensile strength of 421 MPa and tensile yield strength of 309 MPa. It has higher igniting temperature of 1 208 K. Moreover, it can stand against flame at 1 203 K for over 6 min in vertical burning tests, and its flammability behavior is very similar to that of 6101A1 alloy. Vertical burning tests appear to be able to directly study the flammability behavior of Mg alloys and it appears to be a good approach to study the flammability behavior of Mg alloys in an aircraft fire accident.