The application of ultrahigh‐strength martensitic steel in automotive key parts can achieve automotive lightweight. However, the hydrogen embrittlement sensitivity of ultrahigh‐strength martensitic steel is widely concerned by the industry. This article compares the microstructure and the hydrogen brittleness resistance of two 1500 MPa martensitic steels. The grain boundary, the grain size, the martensitic lath, and the precipitate phase in martensitic steel are analyzed by electron backscatter diffraction and transmission electron microscope. The hydrogen desorption curves of the two steels are measured by thermal desorption analysis, and the phenomenon of hydrogen trapping in the materials is analyzed. A U‐bend test is used to compare the hydrogen embrittlement of these two samples. The results demonstrate that the thickness of the martensitic lath and the dislocation are directly related to the diffuse hydrogen concentration in the material. In addition, the Cu‐rich nanoparticles show a better hydrogen trapping effect, which is beneficial in improving the hydrogen embrittlement resistance of the material.

American ginseng (AG), the underground part of Panax quinquefolium L., is composed of four morphological regions, including main root (MR), lateral root (LR), fibrous root (FR), and rhizome (RH). In the clinical, MR is the main medicinal region, other regions are rarely attention. Aiming at revealing the chemical composition of AG and making better use of AG, screening analysis and metabolomic analysis were both performed to profile MR, LR, FR, and RH. First, in the systematical screening analysis, a total of 134 compounds (including 122 shared components) with various structural patterns were identified and tentatively characterized. The results indicated that the phytochemicals with various structural types were rich in MR, LR, FR, and RH. Second, 6, 4, 8, and 11 chemical markers were identified from MR, LR, FR, and RH, respectively. Seven triterpene saponins (protopanaxatriol, quinquenoside R1, ginsenoside Rc, Rk1, Rg1, Re, and vinaginsenoside R1) might be used for rapid differentiation of four morphological regions. This comprehensive profile study of metabolites illustrated the similarities and differences of phytochemicals in four morphological regions of AG. The results could be used for the quality control of AG and furnish a basis for the further development and utilization of AG sources.

The hydrogen embrittlement (HE) fracture of advanced high-strength steels used in lightweight automobiles has received increasing public attention. The source, transmission, and movement of hydrogen, characterization parameters, and test methods of HE, as well as the characteristics and path of HE fractures, are introduced. The mechanisms and modes of crack propagation of HE and hydrogen-induced delayed fracture are reviewed. The recent progress surrounding micro and macro typical fracture characteristics and the influencing factors of HE are discussed. Finally, methods for improving HE resistance can be summarized as follows: (1) reducing crystalline grain and inclusion sizes (oxides, sulfides, and titanium nitride), (2) controlling nano-precipitates (niobium carbide, titanium carbide, and composite precipitation), and (3) increasing residual austenite content under the reasonable tension strength of steel.

Hydrogen embrittlement can easily occur in high strength martensitic steel, manifesting itself as a sudden failure or fracture without warning and greatly threatening the safety of automotive applications. Optimizing the composition of the alloy can be performed by matching heat treatment processing methods and controlling the precipitation amounts to form hydrogen traps. In doing so, the hydrogen embrittlement susceptibility of steel can be effectively delayed, reducing the risk of hydrogen-induced delayed cracking. In this study, four kinds of 1500 MPa strength grade martensitic steel were selected for testing and supplemented with different loadings of Nb and V, respectively. Their grains, phases, and precipitations were compared by optical microscopy (OM), electron backscattered diffraction (ESBD), and transmission electron microscopy (TEM) analyses. After the addition of Nb and V, the microstructure was refined, the residual austenite content increased, and the hydrogen embrittlement resistance was significantly improved.

Jilin Province and Shandong Province are two main American ginseng (AG) producing areas in China. The geographical difference existed in these two provinces. Aiming at evaluating the similarities and differences of the secondary metabolites, the comprehensive metabolite profiling of AG from Jilin Province (AG J ) and Shandong Province (AG S ) was performed based on UPLC-QTOF-MS for the first time. In screening analysis, a total of 111 shared compounds, with ginsenosides being major components, were identified or tentatively characterized, which indicated that AG J and AG S were all rich in phytochemicals and contained similar structural types. Untargeted metabolomics analysis indicated that there were significant differences in the contents of certain constituents in AG J and AG S . Nineteen (12 for AG J , 7 for AG S ) potential producing area-dependent chemical markers were discovered. Based on the contents and MS responses, ginsenoside Rg 1 , Re, and pseudoginsenoside F 11 could be considered as the characteristical markers of AG J , whereas ginsenoside Rg 3 and Rh 2 of AG S .This comprehensive phytochemical profile study could provide valuable chemical evidence for evaluating the characteristics qualities of AG from various producing areas.