Research on a simulation scheme of penetration overload signal

In this paper, the types of penetrating collision overload signals are analyzed, and a detection device for simulating the signal of the penetration process is designed in combination with engineering practice. The device uses asimulated signal generation circuit to simulate the overload signal of the projectile actually hitting the target during the penetration process. The Pspice simulation software is used to simulate the voltage overload of the simulated overload signal, and the feasibility and stability of the signal generation are verified by the prototype test. The simulation signal proposed by the design scheme can be used to simulate the penetration overload signals for different initial speeds and different targets, and it has certain guiding significance for the pre-design simulation test of engineering projects

Pre-strain effect on twist springback of a 3D P-channel in deep drawing

With the widely use of high-strength steel sheets in the automotive industry, the twist springback phenomenon of the steel sheets under multi-step forming conditions has received extensive attention. In this work, the Dual Phase steel DP500 is taken as the research object to investigate the complex non-linear elastoplastic behaviors and twist springback under two-step loading paths. The large specimen with a pre-strain of 4% true strain in rolling direction is carried out on a large tensile testing machine, and several specific blanks are extracted from it at different directions for a subsequent P-channel forming. The influence of twist springback associated with the pre-strain is analyzed. The finite element model based on the non-linear elastic model and the homogeneous anisotropic hardening model (HAH) is also established for the springback prediction and stress analysis. The results indicate that the pre-strain has a considerable impact on the twist springback. The non-linear strain path changes resulted from pre-straining not only influence the residual stress but also affect the elastic modulus distribution.publishe

Postnatal dysregulation of Notch signal disrupts dendrite development of adult-born neurons in the hippocampus and contributes to memory impairment

Deficits in the Notch pathway are involved in a number of neurologic diseases associated with mental retardation or/and dementia. The mechanisms by which Notch dysregulation are associated with mental retardation and dementia are poorly understood. We found that Notch1 is highly expressed in the adult-born immature neurons in the hippocampus of mice. Retrovirus mediated knockout of notch1 in single adult-born immature neurons decreases mTOR signaling and compromises their dendrite morphogenesis. In contrast, overexpression of Notch1 intracellular domain (NICD), to constitutively activate Notch signaling in single adult-born immature neurons, promotes mTOR signaling and increases their dendrite arborization. Using a unique genetic approach to conditionally and selectively knockout notch 1 in the postnatally born immature neurons in the hippocampus decreases mTOR signaling, compromises their dendrite morphogenesis, and impairs spatial learning and memory. Conditional overexpression of NICD in the postnatally born immature neurons in the hippocampus increases mTOR signaling and promotes dendrite arborization. These data indicate that Notch signaling plays a critical role in dendrite development of immature neurons in the postnatal brain, and dysregulation of Notch signaling in the postnatally born neurons disrupts their development and thus contributes to the cognitive deficits associated with neurological diseases

2-(3-Oxo-2,3-dihydro-1,2-benzothia­zol-2-yl)acetic acid

In the title compound, C9H7NO3S, the benzoisothia­zolone ring system is essentially planar, with a maximum deviation of 0.013 (2) Å. In the crystal, mol­ecules are linked via O—H⋯O hydrogen bonds, forming chains along [010]. In addition, weak inter­molecular C—H⋯O hydrogen bonds are present

Stroke-induced damage on the blood–brain barrier

The blood–brain barrier (BBB) is a functional phenotype exhibited by the neurovascular unit (NVU). It is maintained and regulated by the interaction between cellular and non-cellular matrix components of the NVU. The BBB plays a vital role in maintaining the dynamic stability of the intracerebral microenvironment as a barrier layer at the critical interface between the blood and neural tissues. The large contact area (approximately 20 m2/1.3 kg brain) and short diffusion distance between neurons and capillaries allow endothelial cells to dominate the regulatory role. The NVU is a structural component of the BBB. Individual cells and components of the NVU work together to maintain BBB stability. One of the hallmarks of acute ischemic stroke is the disruption of the BBB, including impaired function of the tight junction and other molecules, as well as increased BBB permeability, leading to brain edema and a range of clinical symptoms. This review summarizes the cellular composition of the BBB and describes the protein composition of the barrier functional junction complex and the mechanisms regulating acute ischemic stroke-induced BBB disruption

The K giant stars from the LAMOST survey data I: identification, metallicity, and distance

We present a support vector machine classifier to identify the K giant stars from the LAMOST survey directly using their spectral line features. The completeness of the identification is about 75% for tests based on LAMOST stellar parameters. The contamination in the identified K giant sample is lower than 2.5%. Applying the classification method to about 2 million LAMOST spectra observed during the pilot survey and the first year survey, we select 298,036 K giant candidates. The metallicities of the sample are also estimated with uncertainty of $0.13\sim0.29$\,dex based on the equivalent widths of Mg$_{\rm b}$ and iron lines. A Bayesian method is then developed to estimate the posterior probability of the distance for the K giant stars, based on the estimated metallicity and 2MASS photometry. The synthetic isochrone-based distance estimates have been calibrated using 7 globular clusters with a wide range of metallicities. The uncertainty of the estimated distance modulus at $K=11$\,mag, which is the median brightness of the K giant sample, is about 0.6\,mag, corresponding to $\sim30$% in distance. As a scientific verification case, the trailing arm of the Sagittarius stream is clearly identified with the selected K giant sample. Moreover, at about 80\,kpc from the Sun, we use our K giant stars to confirm a detection of stream members near the apo-center of the trailing tail. These rediscoveries of the features of the Sagittarius stream illustrate the potential of the LAMOST survey for detecting substructures in the halo of the Milky Way.Comment: 24 pages, 20 figures, submitted to Ap