Acoustic test facility at Tianjin spacecraft AIT center of China

The China Academy of Space Technology (CAST) designs and builds a new world-class Assembly, Integration and Test Center (AITC) at Tianjin, China. Modal, vibration and acoustic test facilities are built to support the future environmental testing needs of China space station program. The Reverberation Acoustic Test Facility (RATF) is about 4000 m3 in volume and can achieved an empty chamber acoustic overall sound pressure level (OASPL) higher than 156 dB. It is the largest acoustic facility in Asia. Beijing Institute of spacecraft Environment Engineering (BISEE) started its design and construction work from 2012 and put it into use at October of 2015. The RATF will provide an efficient support for environment testing needs of China and world’s space program in the future

Cloning and biochemical characterization of a novel lipolytic gene from activated sludge metagenome, and its gene product

In this study, a putative esterase, designated EstMY, was isolated from an activated sludge metagenomic library. The lipolytic gene was subcloned and expressed in Escherichia coli BL21 using the pET expression system. The gene estMY contained a 1,083 bp open reading frame (ORF) encoding a polypeptide of 360 amino acids with a molecular mass of 38 kDa. Sequence analysis indicated that it showed 71% and 52% amino acid identity to esterase/lipase from marine metagenome (ACL67845) and Burkholderia ubonensis Bu (ZP_02382719), respectively; and several conserved regions were identified, including the putative active site, GDSAG, a catalytic triad (Ser203, Asp301, and His327) and a HGGG conserved motif (starting from His133). The EstMY was determined to hydrolyse p-nitrophenyl (NP) esters of fatty acids with short chain lengths (≤C8). This EstMY exhibited the highest activity at 35°C and pH 8.5 respectively, by hydrolysis of p-NP caprylate. It also exhibited the same level of activity over wide temperature and pH spectra and in the presence of metal ions or detergents. The high level of stability of esterase EstMY with unique substrate specificities makes it highly valuable for downstream biotechnological applications

The preparation of 3,5-dihydroxy-4-isopropylstilbene nanoemulsion and in vitro release

We have reported a novel procedure to prepare 3,5-dihydroxy-4-isopropylstilbene (DHPS) nanoemulsion, using a low-energy emulsification method. Based on the phase diagram, the optimum prescription of nanoemulsion preparation was screened. With polyoxyethylenated castor oil (EL-40) as the surfactant, ethanol as the co-surfactant, and isopropyl myristate (IPM) as the oil phase, the DHPS nanoemulsion was obtained with a transparent appearance, little viscosity, and spherically uniform distribution verified by transmission electron microscopy and laser scattering analyzer. The nanoemulsion was also determined by FT-Raman spectroscopy. The DHPS nanoemulsion demonstrated good stability and stable physical and chemical properties. The nanoemulsion dramatically improved the transdermal release of DHPS (from 8.02 μg · cm−2 to 273.15 μg · cm−2) and could become a favorable new dosage form for DHPS

Tests of IEEE 1588-based synchronization system in substation

Kao metoda sinkronizacije, IEEE1588 norma je primijenjena u trafostanici, to bi trebalo osigurati ispitanu i provjerenu sinkronizacijku točnost i čvora interoperabilnosti. Metoda sveobuhvatnog testiranja za IEEE1588 se predlaže u ovom radu. Nadalje, IEEE1588 platforma testiranja ure izgrađena je kao podrška predložene metode ispitivanja. Na temelju analize sinkronizacije pogreške ure i metode ispitivanja načela značajke, ocjenjene su točnost i stabilnost glavne ure i pomoćne ure. Drugo, ispitivanje usklađeno s normom za usvajanje odziva značajke je postignuto dizajniranjem konkretnog slučaju, na osnovi navedenog, a potom analizirati pojedinosti provedbe sukladnosti. Prema zahtjevima ispitivanja, dizajnirana je testna osnovna ploča. Konačno, pokus utemeljen na uređajima transfostanice proveden je uporabom IEEE1588 platforme testiranja ure. Izvedivost predloženih metoda dodatno je potvrđena s rezultatima testiranja.As a synchronization method, IEEE1588 standard has been applied in substation, it should be tested and verified ensure synchronization accuracy and node interoperability. A comprehensive testing method for the IEEE1588 is proposed in this paper. Furthermore, IEEE1588 clock testing platform is built to support the proposed testing method. Based on the analysis of the clock synchronization error and the performance testing principle method, the accuracy and stability of master clock and slave clock were evaluated. Secondly, the conformance testing to adopt performance response was achieved by designed specific case, based on the above, and then to analyse the conformance implementation details. According to testing requirements, test bed designed. Finally, the experiment based on substation devices was carried out using the IEEE1588 clock testing platform. The feasibility of the proposed methods was further verified with the testing results

Update on MRI in pediatric intracranial germ cell tumors—The clinical and radiological features

Intracranial germ cell tumors (iGCTs) are uncommon brain tumors that mainly occur in children. Differing in histology, location, and gender of the patients, iGCTs are often divided into germinomas and non-germinomatous germ cell tumors (NGGCTs). Early diagnosis and timely treatment are crucial to iGCTs, the subtypes of which have substantial variations. This review summarized the clinical and radiological features of iGCTs at different sites, and reviewed the recent advances in neuroimaging of iGCTs, which can help predict tumor subtypes early and guide clinical decision-making

Health monitoring device design and application for large synchronously excited multi-shaker vibration test facility

There are different kinds of equipments distributed in different locations for a large complicated multi-shaker vibration test facility, so it is challenging to monitor the real state of test facility thoroughly during its operation. Long-term operation of this test facility will lead to the degradation of reliability and malfunction, and sometimes the emergency stop of the whole test system that threatens the safety of the spacecraft seriously. This paper presents in detail the design and application of a set of health monitoring device for a large multi-shaker vibration test facility which is capable of monitoring the operation state in real time and predicting the potential malfunction of the whole test facility to ensure the reliability of this large test system and safety of the spacecraft during its environmental vibration test