Modeling and Hydrodynamic Characteristics of Bionic Undulate Fin Propeller Driven by Hydraulic

The bionic undulating propeller driven by hydraulic system has different structure, kinematic and dynamic characteristics than that of the common bionic undulating propellers driven by other sources. This paper highlights firstly the structure and driving mechanism of bionic undulating propeller with a hydraulic system, and then setup its kinematic model, based on ruled-surface equation. Changing rules of dynamic mesh for bionic fin is designed based on kinetic model. Later on, the changing courses of hydrodynamic force caused by the bionic undulating fin are calculated and studied with the CFD (Computational Fluid Dynamics) method, as well as the changing characteristics of the fluid pressure field. The analysis showed that while driven by hydraulic system, the bionic propeller could produce full-baseline undulating motion, and has flexible start-up process, as well as doubled-frequency character. The bionic undulating fin driven by hydraulic system puts up flexible characters on both kinematic and dynamics. Key Words: Hydraulic Driven; Undulating Fin; Bionic Propeller; Dynamic Mesh; Hydrodynamic

Heat Transfer and Evaporation Mathematical Model of LNG covered by High Expansion Foam

PresentationWith the expanding of liquefied natural gas (LNG) usage, its security hidden trouble appeared gradually. For security reasons, small-scale experiment was carried out using LN2 (whose thermal physical property parameters is similar to that of LNG, and do not affect the validity of the study) instead of LNG. Observing high expansion foam physical structure after it covering LN2, we find out there's a three layer structure above the LN2 at stable stage, the ice layer (including the tentacles below), freezing foam layer and the foam layer. Through observation and analysis, we build a physical structure model of the foam. A new method to calculate thin film thickness using expansion ratio is proposed, and a heat transfer and evaporation model between foam and LNG in the initial stage is established. Also we build a physical structure model of the ice, and establish a heat transfer and evaporation model between ice and LNG in stable stage. Combined with heat transfer between LNG, ground and cofferdam, the heat transfer and evaporation model of LNG covered with foam was developed eventually

1,2-Bis(1H-tetra­zol-5-yl)benzene dihydrate

The asymmetric unit of the title compound, C8H6N8·2H2O, contains one half-mol­ecule, with the benzene ring on a centre of symmetry, and two uncoordinated water mol­ecules. The benzene ring is oriented at a dihedral angle of 34.43 (12)° with respect to the tetra­zole ring. Strong O—H⋯N hydrogen bonds link the water mol­ecules to the N atoms of the tetra­zole ring. In the crystal structure, strong inter­molecular O—H⋯O and O—H⋯N hydrogen bonds link the mol­ecules into a network. One of the water H atoms is disordered over two positions and was refined with occupancies of 0.50

Detection of recurrent 4p16.3 microdeletion with 2p25.3 microduplication by multiplex ligation-dependent probe amplification and array comparative genomic hybridization in a fetus from a family with Wolf–Hirschhorn syndrome

AbstractObjectiveWe present prenatal diagnosis, genetic counseling, and molecular cytogenetic features of familial recurrence of Wolf–Hirschhorn syndrome (WHS).Materials and methodsA 31-year-old woman was referred to a hospital at 24 weeks of gestation because of abnormal ultrasound findings in the fetus. Her first child was a boy who had growth retardation, mental defect, and a distinctive facial appearance. Based on the conventional cytogenetic analysis, the combined use of multiplex ligation-dependent probe amplification (MLPA) and array comparative genomic hybridization (aCGH) facilitated the prenatal diagnosis and genetic counseling in the fetus.Results of the standard G-banging karyotype analysis of the fetus, the parents, and the boy were normal.ResultsThe MLPA analysis revealed the same 4p microdeletion accompanied by 2p microduplication in the fetus and the boy. The aCGH analysis revealed a 3.57-Mb 4p16.3 microdeletion or arr [hg19] 4p16.3 (71,552–3,636,893) x1 in the fetus and a 3.29-Mb 4p16.3 microdeletion or arr [hg19] 4p16.3 (71,148–3,360,737) x1 in the boy. The 3.57-Mb 4p16.3 microdeletion encompassed 39 OMIM genes. The 3.29-Mb 4p16.3 microdeletion encompassed 36 OMIM genes. They both included LETM1 and WHSC1. The 2p25.3 microduplication was smaller than 666 kb and encompassed only one OMIM gene, ACP1.ConclusionThe combined use of MLPA and aCGH is an effective way to diagnose recurrent WHS. Although WHS is typically caused by a de novo deletion, prenatal diagnosis and genetic counseling are necessary in the next pregnancy in families that have suffered such cases

Synergistic Effect of Ferulic Acid and Z-Ligustilide, Major Components of A. sinensis

Angelica sinensis has been used to attenuate cold-induced cutaneous vasospasm syndrome, such as Raynaud’s disease and frostbite, in China for many years. Ferulic acid (PubChem CID: 445858) and Z-ligustilide (PubChem CID: 529865), two major components extracted from Angelica sinensis, had been reported to inhibit vasoconstriction induced by vasoconstrictors. In this study, the pharmacological interaction in regulating cold-induced vascular smooth muscle cell contraction via cold-sensing protein TRPM8 and TRPA1 was analyzed between ferulic acid and Z-ligustilide. Pharmacological interaction on inhibiting [Ca2+]i influx evoked by TRPM8 agonist WS-12 or TRPA1 agonist ASP 7663 as well as cold-induced upregulation of TRPM8 was determined using isobolographic analysis. The isobolograms demonstrated that the combinations investigated in this study produced a synergistic interaction. Combination effect of two components in inhibiting RhoA activation and phosphorylation of MLC20 induced by WS-12 or ASP 7663 was also being quantified. These findings suggest that the therapeutic effect of Angelica sinensis on cold-induced vasospasm may be partially attributed to combinational effect, via TRPM8 and TPRA1 way, between ferulic acid and Z-ligustilide

Thermal Analysis and Characterization of Polystyrene Initiated by Benzoyl Peroxide

PresentationBased on the complexity of the polystyrene polymerization mechanism initiated by benzoyl peroxide (BPO), the thermal risk of the reaction process was estimated using thermal analysis and characterization. The polymerization process was thermally analysed using an adiabatic rate calorimeter and differential scanning calorimeter. The results demonstrated that the onset reaction temperature, adiabatic temperature rise, and maximum temperature of the synthesis reaction of BPO-initiated polymerization were lower than those of thermos initiated polymerization. Moreover, nuclear magnetic resonance imaging, gel permeation chromatography, and Fourier transform infrared spectrometry were used to characterize the polymerization products obtained under the two initiation conditions. The polystyrene obtained using the two initiation methods had the same hydrogen structure; however, their molecular weight and distribution uniformity differed considerably, and the BPO-initiated process was discovered to include the effects of the thermos initiated process. Moreover, the free radicals produced by BPO decomposition participated in the chain reaction of polystyrene polymerization, accelerated instantaneous grain growth, and promoted the formation of short- chain polystyrene. In summary, the BPO-initiated polymerization process exhibited the desired thermal safety characteristics and has potential for practical use

Free-running 4H-SiC single-photon detector with ultralow afterpulse probability at 266 nm

Ultraviolet single-photon detector (UVSPD) provides a key tool for the applications requiring ultraweak light detection in the wavelength band. Here, we report a 4H-SiC single-photon avalanche diode (SPAD) based free-running UVSPD with ultralow afterpulse probability. We design and fabricate the 4H-SiC SPAD with a beveled mesa structure, which exhibits the characteristic of ultralow dark current. We further develop a readout circuit of passive quenching and active reset with tunable hold-off time setting to considerably suppress the afterpulsing effect. The nonuniformity of photon detection efficiency (PDE) across the SPAD active area with a diameter of $\sim$ 180 $\mu$m is investigated for performance optimization. The compact UVSPD is then characterized, exhibiting a typical performance of 10.3% PDE, 133 kcps dark count rate and 0.3% afterpulse probability at 266 nm. Such performance indicates that the compact UVSPD could be used for practical ultraviolet photon-counting applicationsComment: 5 pages, 5 figures, accepted for publication in Review of Scientific Instrument

Seasonal variation in systemic lupus erythematosus and rheumatoid arthritis: an ecological study In based on internet searches

Systemic lupus erythematosus (SLE) is a prototypical autoimmune disease in which immune regulation is disrupted and characterized by intense inflammation and damage to multiple organs or systems. Rheumatoid arthritis (RA) is another systemic autoimmune disease characterized by chronic synovial joint inflammation that leads to disability and poor quality of life. Although the etiologies and pathogenesis of SLE and RA are not fully understood, it is generally accepted that they are both caused by interactions between genetic and environmental factors. In recent years, emerging studies have demonstrated the potential role of seasonality in the development and disease activity of variety of autoimmune diseases [[1], [2], [3]]