A Review of Vacuum Degradation Research and the Experimental Outgassing Research of the Core Material- Pu foam on Vacuum Insulation Panels

AbstractVacuum Insulation Panels(VIPs) have been regarded as a super thermal insulation material with a thermal resistance of about 5-8 times higher than that of equally thick conventional polyurethane boards. In this paper, the researches on factors influencing interior pressure in VIPs, including gas and water vapor permeation through the barrier and outgassing of the core materials, were reviewed respectively. Following this, aiming at the outgassing from open cell PU foam, the specific outgassing rate of the core material is tested not only at room temperature but also at low and high temperatures by an orifice known-conductance method

Optimization Analysis of Initial Sheet Metal Contour Line for High-Strength Boron Steel in Hot Stamping

Based on the principle of hot stamping, a simulation model of hot stamping was established. The blank contour line of U part was optimized by using a multiple iterative algorithm. By comparison with the simulation and experimental data, the multiple iterative optimization algorithm was verified. Moreover, the blank contour lines of a bumper and the B-pillar of Numisheet 2008 were optimized. The result showed that the multiple iterative method for optimizing initial blank contour line had high calculating speed and precision. The hot stamping parts’ contour lines match the ideal part contour lines quite well

Comparison of Structural Development and Biochemical Accumulation of Waxy and Non-waxy Wheat Caryopses

This study was conducted to compare structural development and biochemical accumulation of waxy and non-waxy wheat (NW) caryopses. The caryopses’ microstructure of the waxy wheat (WW) and NW cultivars at different developmental stages were observed under light, fluorescence, and scanning electron microscope. The results were as follows: Compared with NW,WWhad a shorter maturation duration, which was reflected in several following characteristics. Programmed cell death of the pericarp began earlier, and the chlorophyll-containing layer in the pericarp was smaller. Vacuoles in chalazal cells accumulated more tannins at different developmental stages. Starch granules and protein bodies in the endosperm showed a higher accumulation level in developing caryopses, and aleurone cells were larger in size with larger numbers of aleurone grains. An analysis of the element content indicated that the mineral elements Mg, P, K, and Ca exhibited a higher content, while the heavy elements Cr, Cd, and Pb exhibited a lower content in the aleurone layer

In vitro and in vivo anticancer activity of steroid saponins of paris polyphylla var. yunnanensis

Aim: To confirm the anticancer activity of steroid saponins isolated from the rhizome of Paris polyphylla var. yunnanensis and evaluate the structure-activity relationships of these steroid saponins in vitro and in vivo. Materials and Methods: Eight known steroid saponins were isolated from the rhizome of Paris polyphylla. The LA795 lung adenocarcinoma cell line from mice was chosen to evaluate cytotoxicity by means of MTT assay, and to study apoptosis by means of AnnexinV-FITC/PI flow cytometry. Diosgenin-3-α-L-arabinofuranosyl(1→4)-[α-L-rhamnopyranosyl(1→2)]-β-D-glycopyranoside (compound 1), the main steroid saponin of Paris polyphylla, and diosgenin (Dio), the aglycone of major steroid saponins, were evaluated for antitumor activity on LA795 lung adenocarcinoma in T739 inbred mice. Results: The steroid saponins showed remarkable cytotoxicity and caused typical apoptosis in a dose-dependent manner. They were evaluated in vivo by their effect on tumor developed in T739 inbred mice. The oral administration to T739 mice bearing LA795 lung adenocarcinoma of compound 1 and diosgenin significantly inhibited tumor growth, by 29.44% and 33.94%, respectively. HE staining showed that lungs and livers of treated mice underwent various levels of histopathological alterations. It was demonstrated by TUNEL assay that apoptosis rate in tumor cells was increased in comparison to cells in control mice. The 3-O-glycoside moiety and spirostanol structure played an important role in the anticancer activity of steroid saponins, and the number and the variety of glycosides of compounds strongly influenced on their anticancer activity. Conclusion: Rhizoma Paridis saponins showed anticancer activity against lung adenocarcinoma cell line, both in vitro and in vivo, and their effect was dependent on compounds’ structure in a certain degree

Study on a Cracked Single-Layer 2D Woven Composite Plate: Fracture Mode and Damage Analysis

An experimental study and numerical calculation are conducted to investigate the crack propagation in a 2D woven composite. Crack propagation tests of single-layer composite plate specimens permit this process to be directly followed. Analysis of their fracture surfaces reveals crack propagation paths, fracture mode, and damage mechanisms. The load–deflection curve represents the crack propagation as a three-stage process. The stress intensity near the crack tip is evaluated with the critical stress intensity factor numerically calculated. The results demonstrate a good agreement between the calculations and experiment.Проведены экспериментальные исследования и численные расчеты для изучения распространения трещин плоского тканого композита. Благодаря испытанию на распространение трещин в однослойной композитной пластине можно непосредственно наблюдать процесс распространения трещин. Анализ поверхностей разрушенных образцов позволяет установить траекторию распространения трещин, характер разрушения и механизмы повреждения. Согласно кривой нагрузка–перемещение, процесс распространения трещин разделяется на три стадии. Для исследования интенсивности напряжений в вершине трещины образцов определяется критический коэффициент интенсивности напряжений путем численных расчетов. Полученные результаты демонстрируют хорошее соответствие расчетных данных с экспериментальными

Ultrastrong conductive in situ composite composed of nanodiamond incoherently embedded in disordered multilayer graphene

Traditional ceramics or metals cannot simultaneously achieve ultrahigh strength and high electrical conductivity. The elemental carbon can form a variety of allotropes with entirely different physical properties, providing versatility for tuning mechanical and electrical properties in a wide range. Here, by precisely controlling the extent of transformation of amorphous carbon into diamond within a narrow temperature–pressure range, we synthesize an in situ composite consisting of ultrafine nanodiamond homogeneously dispersed in disordered multilayer graphene with incoherent interfaces, which demonstrates a Knoop hardness of up to ~53 GPa, a compressive strength of up to ~54 GPa and an electrical conductivity of 670–1,240 S m(–1) at room temperature. With atomically resolving interface structures and molecular dynamics simulations, we reveal that amorphous carbon transforms into diamond through a nucleation process via a local rearrangement of carbon atoms and diffusion-driven growth, different from the transformation of graphite into diamond. The complex bonding between the diamond-like and graphite-like components greatly improves the mechanical properties of the composite. This superhard, ultrastrong, conductive elemental carbon composite has comprehensive properties that are superior to those of the known conductive ceramics and C/C composites. The intermediate hybridization state at the interfaces also provides insights into the amorphous-to-crystalline phase transition of carbon

Long-distant contribution and χc1\chi_{c1} radiative decays to light vector meson

The discrepancy between the PQCD calculation and the CLEO data for $\chi_{c1}\to \gamma V$ ($V=\rho^0,\,\omega,\,\phi$) stimulates our interest in exploring extra mechanism of $\chi_{c1}$ decay. In this work, we apply an important non-perturbative QCD effect, i.e., hadronic loop mechanism, to study $\chi_{c1}\to \gamma V$ radiative decay. Our numerical result shows that the theoretical results including the hadronic loop contribution and the PQCD calculation of $\chi_{c1}\to \gamma V$ are consistent with the corresponding CLEO data of $\chi_{c1}\to \gamma V$. We expect further experimental measurement of $\chi_{c1}\to \gamma V$ at BES-III, which will be helpful to test the hadronic loop effect on $\chi_{c1}$ decay.Comment: 7 pages, 2 figures. Accepted for publication in Eur. Phys. J.