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Aluminum radiator plays a significant role in thermal managing system of passive heat dissipation for high power consuming microelectronic devices. Although inspiring strategies have been proposed to design and prepare polymer-based composites with high thermal conductivity in previous reports, it remains urgent to develop practical techniques for economically fabricating thermally conductive composite coatings in large-scale. To construct efficient heat dissipation film, two-dimensional (2D) graphene nanoplatelets (GNPs)/hexagonal boron nitride nanoplatelets (BNNPs) hybrid fillers are dispersed in polydimethylsiloxane (PDMS) solution with branch-like porous magnéli-phase Ti4O7 microparticles as heat conducting paths, and fabricated via convenient spray-coating. Thermal conductivity of the cured coating presents two-fold increase to 5.339 W m−1 K−1 as compared to the coating without Ti4O7, and a heat dissipation ratio of 13.96 %. Furthermore, the composite coating demonstrates excellent corrosion resistance under neutral salt solution spray. The as-prepared composite coating is of great potential to be applied as protective coating for aluminum radiators.

The modified N50 (N50H) cable-in-conduit conductor CICC jacket developed by China will be applied in China Fusion Engineering Test Reactor (CFETR). Building upon the N50H material, China has developed a corresponding welding material and conducted R&D work on N50H jacket welding. We simulated the N50H jacket welded joint to replicate the entire process of CICC preparation, which includes extrusion, bending, straightening and aging. The magnetic properties of welded joints were evaluated at various temperatures using a physical property measurement system. In addition, the microstructure of the welded joint was studied by various microscopic analysis techniques, and the welded joint showed a stable austenitic structure. Furthermore, mechanical properties of the welded joints were investigated at different temperatures with particular emphasis on their behavior at 4.2 K. The circle-in-square ReBCO conductor jackets welding joint showed a yield strength greater than 1500 MPa, a fracture toughness KIC better than 260 MPa m1/2 and the elongation at break is more than 30 % at 4.2 K. However, a decrease in strength, ductility, and fracture toughness is observed within the welded joints of Nb3Sn conductor jackets after undergoing an aging process. This study will present experimental data on welding joints and discuss the feasibility of N50H as a high-magnetic field jacket material for next-generation fusion reactors.

Developing cryogenic structural materials with high strength and toughness is a challenge for the high-field superconducting magnet of the future fusion reactor. 0.2% proof stress should be over 1500 MPa and the fracture toughness KIC should be better than 130 MPa·m1/2 at 4.2 K for future cable-in-conduit conductors (CICC) jackets. Thus the cryogenic structural materials of modified 316LN, JK2LB, Incoloy 908, and JJ1 developed by ITER do not meet the requirements. Based on Nitronic 50 (N50) super-austenitic stainless steel material, the modified N50 (N50H) developed in China shows excellent low-temperature mechanical properties by completely eliminating δ ferrite and strictly controlling the carbon content of the alloy. Meanwhile, the jackets of CICC were prepared with N50H material for the first time, and some R&D work has been done. The N50H jackets have been compacted to final dimensions, bent to a radius of r = 2000 mm, straightened, and aging treated. The yield strength of N50H circle-in-square jackets is greater than 1550 MPa, and the fracture toughness KIC is better than 150 MPa·m1/2 at 4.2 K. The fatigue crack growth rate (FCGR) of the N50H jacket is lower than that of the modified 316LN, JK2LB and close to Incoloy 908. This study will present experimental data of modified 316LN, JK2LB, Incoloy 908, JJ1, and N50H. Moreover, this paper discusses the feasibility of N50H as a high-magnetic field cryogenic structural material for next-generation fusion reactors.

Primary bone tumors especially, sarcomas affect adolescents the most because it originates from osteoblasts cells responsible for bone growth. Chemotherapy, surgery, and radiation therapy are the most often used clinical treatments. Regrettably, surgical resection frequently fails to entirely eradicate the tumor, which is the primary cause of metastasis and postoperative recurrence, leading to a high death rate. Additionally, bone tumors frequently penetrate significant regions of bone, rendering them incapable of self-repair, and impairing patients' quality of life. As a result, treating bone tumors and regenerating bone in the clinic is difficult. In recent decades, numerous sorts of alternative therapy approaches have been investigated due to a lack of approved treatments. Among the novel therapeutic approaches, hydrogel-based anticancer therapy has cleared the way for the development of new targeted techniques for treating bone cancer and bone regeneration. They include strategies such as co-delivery of several drug payloads, enhancing their biodistribution and transport capabilities, normalizing accumulation, and optimizing drug release profiles to decrease the limitations of current therapy. This review discusses current advances in functionalized hydrogels to develop a new technique for treating bone tumors by reducing postoperative tumor recurrence and promoting tissue repair.

To excite stronger magnetic fields, high temperature superconducting (HTS) insert coils are planned for the next generation central solenoid magnet for China fusion engineering test reactor (CFETR). The development of high strength and high toughness jacket has become one of the challenges in the application of high-field cable-in-conduit conductors (CICC). 0.2 % proof stress of jacket should be over 1500 MPa at 4.2 K for HTS conductors, thus 316LN and JK2LB jackets developed by ITER do not meet the requirements. Nitronic 50 (N50) super-austenitic stainless steel material has great optimization potential for the development of jacket. Based on the modified N50 material, China prepared the CICC jacket and has done some R&D work on the N50 jacket. The entire process of ReBCO CICC preparation, including extrusion, bending and straightening, was simulated using the N50 stainless steel jacket. The N50 circle-in-square jackets prepared in China showed a yield strength greater than 1600 MPa and a fracture toughness KIC better than 110 MPa·m1/2 after cold work at 4.2 K. This paper will focus on the preparation, cold work processing and performance test of the N50 jacket. This study will present experimental data and discuss the feasibility of modified N50 as a high-magnetic field jacket material for next-generation fusion reactors.

Understanding weathering processes in landslide-dominated catchments is critical for evaluating the role of landslides in chemical weathering and the global carbon cycle. Previous studies have focused on solute concentrations in landslide-impacted landscapes, but have paid less attention to developing isotopic tracers of landslide-induced weathering fluxes. Recent work found that the dissolved radiogenic uranium isotopes in river water are closely related to the denudation rates in catchments draining steep mountains where landslides are thought to be a major erosion mechanism, suggesting the potential of uranium isotopes to trace landslide-induced weathering fluxes. Here we compile the dissolved radiogenic uranium isotopes (234U/238U ratios) in the river water samples from a group of catchments with variable landslide activities in the Minjiang River Basin at the eastern margin of the Tibetan Plateau. We derive three metrics of landslide activity from the analyses of digital topography and an inventory map of the co-seismic landslides triggered by the 2008 Mw7.9 Wenchuan earthquake: the normalized volume of landslides, the mean catchment slope angle, and the fraction of slopes steeper than a threshold angle beyond which slopes are mechanically unstable. The riverine dissolved 234U/238U ratios correlate negatively with the metrics of landslide activity in each catchment, which likely reflect the influence of landslides on the dissolved 234U/238U ratios. Mechanistically, enhanced bedrock landsliding would accelerate the exposure of fresh rock, promoting bedrock weathering and congruent dissolution of 234U and 238U contained in minerals; reduced landslide activities and enhanced regolith weathering would lead to preferential accumulation of 234U against 238U in solutes through alpha-recoil ejection, thus increasing dissolved 234U/238U. Our findings provide field evidence of using the riverine dissolved 234U/238U ratio to trace weathering fluxes driven by landslides, shedding new light on chemical weathering processes in uplifting mountains.

Co-Cr-Fe-Ni-Mn high entropy alloys (HEAs) have attracted extensive attention due to their broad cryogenic engineering application potential, reasonable control of alloying elements can significantly improve its mechanical performance. In this work, the effects of Co content on the phase stability and mechanical behavior CoxCrFeNiMnAl0.3 HEAs were investigated. It is found that with the decrease of the Co content, the stability of the face-centered cubic (FCC) solid solution phase in the alloy decreases, resulting in the precipitation of the BCC (body-centered cubic) phase from the FCC phase, thereby obtaining the FCC + BCC dual-phase structure. During annealing, the precipitated BCC phase can effectively suppress the grain growth and recrystallization of the FCC solid solution, forming an ultrafine-grained microstructure. In addition, the Ni-Al type nano-B2 phase can form in the BCC phase under the influence of the negative formation enthalpy during solidification. This micro/nano hierarchical structure can effectively improve the mechanical properties of the alloys. Co0.25CrFeNiMnAl0.3 maintains relatively excellent tensile yield strength (486 MPa), the tensile elongation remains above 20 %. This study regulates the formation of the BCC phase and B2 phase by reducing the content of Co, which provides a new idea for the preparation of low-cost HEAs with excellent mechanical properties.

The negative thermal expansion (NTE) or nearly zero thermal expansion (NZTE) behaviors have been found in some magnetic metallic compounds with great application prospects. However, it is a big challenge for applications that the responding temperature range is not broad enough or far away from room temperature. Herein, a new method is put forward to design the wide temperature range of NTE and NZTE Behavior by NTE/NZTE multi-phase composite. In this method, the optimized volume fraction of the components achieves a concordant collaboration of multi-phase in the counteraction of NTE and positive thermal expansion (PTE) at several adjacent temperature ranges and thus the temperature range is broadened as expected. By this method, MnCuGeN-based NTE composite (290 K ≤ T ≤ 385 K, ΔT = 95 K) and MnCuZnSiGeN-based NZTE composite (200 K ≤ T ≤ 400 K, ΔT = 200 K) with excellent stability have been successfully designed and prepared. This idea will open an avenue to the multi-phase composite with designable NTE/NZTE properties, which would have important applications in aerospace and other modern industries.

Thermosetting polymer materials with excellent mechanical properties are highly promising in cryogenic engineering applications. However, the research on the toughening mechanism of thermosetting materials at cryogenic temperatures is always difficult. Herein, one type of high strength hyperbranched epoxy composite was successfully fabricated, and the correlation between microstructure (free volume) and mechanical properties of the HPB/epoxy composites was studied. To disclose the correlations between mechanical properties and microstructures for these composites, positron annihilation lifetime (PAL) measurements were carried out. Thereafter, better impact and compression properties were observed for composites with smaller free volume holes. Meanwhile, the impact and tensile properties of the composites are positively correlated with the free volume holes fraction at 77 K. The correlation between microstructure and mechanical properties provide valuable information for regulating the cryogenic mechanical properties of thermosetting materials in the future.

The database of thermal expansion behavior of closed-cell polyurethane rigid foam at very low temperatures is required for designing and manufacturing thermal insulation components of various cryogenic systems. In the present work, thermal expansion behaviors of closed-cell polyurethane rigid foams with different densities were investigated in the 20 K–270 K temperature range by means of a high-resolution extensometer technique, which has been verified through comparison with standard values of an AISI 304 stainless steel rod. The comparison result demonstrates that the maximum deviation from the standard coefficient of thermal expansion of the AISI 304 in cryogenic temperatures is less than 6.6%. Testing results indicate that the cryogenic thermal expansions of closed-cell polyurethane rigid foams depend reversely on density. Moreover, the thermal expansion behavior of closed-celled polyurethane rigid foams exhibits difference from that of bulky amorphous isotropic polymers, which have been attributed to several factors such as enclosed air and cellular structure.

Control of negative thermal expansion (NTE) is of great importance for various applications of NTE materials. Here, we report an effective way to control both the coefficient of thermal expansion (CTE) and NTE temperature-window in NaZn13-type La(Fe, Co, Al)13 compounds by Al and Co substitutions. Experiments show that the average CTE decreases with the increase in Al content. Besides, the NTE temperature-window shifts toward higher temperature due to Co doping. Further studies of magnetic characterizations reveal that the CTE is strongly correlated with the square of the spontaneous magnetization Ms2(T). Moreover, the NTE temperature-window is influenced by the density of 3d electrons at the Fermi level and the FeI–FeII magnetic exchange interactions. This effective way demonstrated in this work to achieve controllable NTE indicates the potentials in practical applications for NTE materials.

S and Te-doped Cu2SnSe3 samples with chemical formula of Cu2SnSe3-xSx and Cu2SnSe3-xTex (x = 0.05, 0.10, 0.15, 0.20) are prepared, and the effect of S and Te-doping on thermoelectric properties is investigated. In all the samples, the Cu2SnSe3 phase is synthesized as the major product, and its lattice parameters decrease with S-doping but increase with Te-doping. EDS analysis confirms the incorporation of S and Te dopants in the Cu2SnSe3 phase, and reveals an element segregation in the Te-doped samples. S- and Te-doping decreases the electrical conductivity, enhance the Seebeck coefficient, and reduce the thermal conductivity. S-doping is effective to improve the ZT of Cu2SnSe3, and the Cu2SnSe3-xSx sample with x = 0.05 shows a ZT of 0.66 at 773 K, which is improved by more than 50% compared with that of the undoped sample. On the contrary, Te-doping leads to decreased ZT values owing to the significant reduction in electrical conductivity.

The present work describes the monitoring system of the real-time strain response on the curing process of epoxy resin from the initial point of curing to the end, and the change in strain during temperature changes. A simple mould was designed to embed the strain gauge, thermometer, and quartz standard sample into the epoxy resin, so that the strain and the temperature were simultaneously measured and recorded. A cryogenic-grade epoxy resin was tested and the Differential Scanning Calorimetry (DSC) was used to analyse the curing process. Based on the DSC results, three curing processes were adopted to investigate their influence on strain response as well as residual strain of the epoxy resin. Moreover, impact strength of the epoxy resin with various curing temperatures were tested and the results indicate that the curing plays a crucial role on the mechanical properties. The method will find cryogenic application of epoxy adhesives and epoxy resin based composites to monitor the strain during the curing process as well as the cryogenic service.

Thermal expansion is a crucial factor for the performance of laser devices, since the induced thermal stress by laser irradiation would strongly affect the optical beam quality. For BaAlBO3F2 (BABF), a good non-linear optical (NLO) crystal, due to the highly anisotropic thermal expansion its practical applications are strongly affected by the “tearing” stress with the presence of local overheating area around the laser spot. Recently, the strategy to place the optical crystals in low-temperature environment to alleviate the influence of the thermal effect has been proposed. In order to understand the prospect of BABF for this application, in this work, we investigated its thermal expansion behavior below room temperature. The variable-temperature XRD showed that the ratio of thermal expansion coefficient between along c- and along a(b)- axis is high as 4.5:1 in BABF. The Raman spectrum combined with first-principles phonon analysis revealed that this high thermal expansion anisotropy mainly ascribe to progressive stimulation of the respective vibration phonon modes related with the thermal expansion along a(b)- and c-axis. The good NLO performance in BABF can be kept below room temperature. The work presented in this paper provides an in-depth sight into the thermal expansion behavior in BABF, which, we believe, would has significant implication to the manipulation in atomic scale on the thermal expansion of the materials adopted in strong-field optical facility.

Thermal expansion and magnetostriction, the strain responses of a material to temperature and a magnetic field, especially properties at low temperature, are extremely useful to study electronic and phononic properties, phase transitions, quantum criticality, and other interesting phenomena in cryogenic engineering and materials science. However, traditional dilatometers cannot provide magnetic field and ultra-low temperature (

Thermally conductive but electrically insulating materials are highly desirable for thermal management applications in electrical encapsulation and future energy fields, for instance, superconducting magnet insulation in nuclear fusion systems. However, the traditional approaches usually suffer from inefficient and anisotropic enhancement of thermal conductivity or deterioration of electrical insulating property. In this study, using boron nitride sphere (BNS) agglomerated by boron nitride (BN) sheets as fillers, we fabricate a series of epoxy/BNS composites by a new approach, namely gravity-mix, and realize the controllable BNS loading fractions in the wide range of 5−40 wt%. The composites exhibited thermal conductivity of about 765% and enhancement at BNS loading of 40 wt%. The thermal conductivity up to 0.84 W·m−1·K−1 at 77 K and 1.66 W·m−1·K−1 at 298 K was observed in preservation of a higher dielectric constant and a lower dielectric loss, as expected, because boron nitride is a naturally dielectric material. It is worth noting that the thermal property was almost isotropous on account of the spherical structure of BNS in epoxy. Meanwhile, the reduction of the coefficient of thermal expansion (CTE) was largely reduced, by up to 42.5% at a temperature range of 77−298 K.