Combustion Characteristics of Coated Nano Aluminum in Composite Propellants

The effects of coated nano-sized aluminum (Al) powder (n-Al) and micron-sized Al powder(g-Al) in propellants on the burning rate and pressure exponent have been investigated. Theresults show that the burning rates of propellants increase as the n-Al content increases, butthe burning rate pressure exponents tend to decrease. Compared with propellant containing-Al, the increments of burning rates of propellants containing n-Al powder reduce graduallywith increase in the pressure because of the differences of the combustion characteristics andignition performances of n-Al powder and g-Al powder. Single short distance photograph, scanningelectron microscopy, x-ray fluorescence analysis were used to characterise the flame image,combustion phenomena, the quenched surface image, and surface elements. A substantialdifference in combustion characteristics of n-Al powder has been found in comparison with-Al powder. In addition, oxygen-bomb combustion heat, ignition temperature, and recoveryratio of residues were measured

Effect of Nitrate Ester on the Combustion Characteristics of PET/HMX -based Propellants

The effect of nitrate ester NG/TEGDN on the combustion characteristics of PET/HMX-based propellants has been experimentally investigated using of high-speed photography technique and scanning electron microscopy. It is indicated that the increase of NG/TEGDN content has little impact on the propellant burning rates at the same pressure. Furthermore, propellant can not be self-sustaining combustion at low pressure (£1 MPa). The increase of NG/TEGDN content does not affect the flame structure of propellant, but it plays an important role in condensed phase reaction zone. The flame structure of propellant is estimated. The thermal decomposition products in different combustion zones are also discussed. Scanning electron microscopy examination of quenched sample indicates that a liquified layer forms during combustion of these propellants. Numerous gas bubbles are present. Especially, the burning surface of propellant with low NG/TEGDN content shows signs of crystallization. The thickness of condensed phase reaction zone, by cross-section examination of propellant burning surface, has also been investigated. The results show that the thickness of condensed phase reaction zone increases with NG/TEGDN content increasing. These observations suggest that the condensed phase zone plays significant role in propellant combustion.Defence Science Journal, 2011, 61(3), pp.206-213, DOI:http://dx.doi.org/10.14429/dsj.61.56

PHOTOMETRIC OBSERVATIONS OF 782 MONTEFIORE, 3842 HARLANSMITH, 5542 MOFFATT, 6720 GIFU, AND (19979) 1989 VJ

Five solar system minor planets were measured photometrically between 2012 October and December using the SARA (Southeastern Association for Research in Astronomy) telescopes located in Kitt Peak National Observatory in USA and Cerro Tololo Inter-American Observatory in Chile. The following synodic periods were found: 782 Montefiore P = 4.0728 ± 0.0006 h; 3842 Harlansmith, P = 2.7938 ± 0.0005 h; 5542 Moffatt P = 5.187 ± 0.001 h; 6720 Gifu, P = 4.231 ± 0.001 h; and (19979) 1989 VJ, P = 7.568 ± 0.005 h

VHL and PTEN loss coordinate to promote mouse liver vascular lesions

Von Hippel-Lindau (VHL) inactivation develops a tumor syndrome characterized by highly vascularized tumors as a result of hypoxia inducible factors (HIF) stabilization. The most common manifestation is the development of hemangioblastomas typically located in the central nervous system and other organs including the liver. PTEN (Phosphatase and tension homologue deleted on chromosome 10) inactivation also upregulates HIF-1α and may take part in promoting vascular lesions in tumors. The coordinate effect of loss of these tumor suppressors on HIF levels, and the subsequent effect on vascular lesion formation would elucidate the potential for mechanisms to modify HIF dosage supplementally and impact tumor phenotype. We therefore employed models of somatic conditional inactivation of Vhl, Pten, or both tumor suppressor genes in individual cells of the liver by Cre-loxP recombination to study the cooperativity of these two tumor suppressors in preventing tumor formation. Nine months after tumor suppressor inactivation, Vhl conditional deletion (VhlloxP/loxP) mice showed no abnormalities, Pten conditional deletion (PtenloxP/loxP) mice developed liver steatosis and focal nodular expansion of hepatocytes containing lipid droplet and fat. Vhl and Pten conditional deletion (VhlloxP/loxP; PtenloxP/loxP) mice, however, developed multiple cavernous liver lesions reminiscent of hemangioblastoma. Liver hemangioblastomas in VHL disease may, therefore, require secondary mutation in addition to VHL loss of heterozygosity which is permissive for vascular lesion development or augments levels of HIF-1α

Decimetre-scale multicellular eukaryotes from the 1.56-billion-year-old Gaoyuzhuang Formation in North China

Fossils of macroscopic eukaryotes are rarely older than the Ediacaran Period (635–541 million years (Myr)), and their interpretation remains controversial. Here, we report the discovery of macroscopic fossils from the 1,560-Myr-old Gaoyuzhuang Formation, Yanshan area, North China, that exhibit both large size and regular morphology. Preserved as carbonaceous compressions, the Gaoyuzhuang fossils have statistically regular linear to lanceolate shapes up to 30 cm long and nearly 8 cm wide, suggesting that the Gaoyuzhuang fossils record benthic multicellular eukaryotes of unprecedentedly large size. Syngenetic fragments showing closely packed ∼10 μm cells arranged in a thick sheet further reinforce the interpretation. Comparisons with living thalloid organisms suggest that these organisms were photosynthetic, although their phylogenetic placement within the Eukarya remains uncertain. The new fossils provide the strongest evidence yet that multicellular eukaryotes with decimetric dimensions and a regular developmental program populated the marine biosphere at least a billion years before the Cambrian Explosion

Aberrant structural and functional alterations in postpartum depression: a combined voxel-based morphometry and resting-state functional connectivity study

ObjectivesPostpartum depression (PPD) is a severe postpartum psychiatric disorder with unclear pathogenesis. Previous neuroimaging studies have reported structural or functional alterations in areas associated with emotion regulation, cognitive disorder, and parenting behaviors of PPD. The primary goal of this investigation was to explore the presence of brain structural alterations and relevant functional changes in PPD patients.MethodsA total of 28 patients and 30 matched healthy postnatal women (HPW) underwent both three-dimensional T1-weighted magnetic resonance imaging (MRI) and resting-state functional MRI. Structural analysis was performed by voxel-based morphometry (VBM), followed by resting-state functional analysis using a seed-based whole-brain functional connectivity (FC) approach with abnormal gray matter volume (GMV) regions as seed.ResultsCompared with HPW, the PPD patients showed increased GMV in the left dorsolateral prefrontal cortex (DLPFC.L), the right precentral gyrus (PrCG.R), and the orbitofrontal cortex (OFC). In the PPD group, the DLPFC.L showed increased FC with the right anterior cingulate and paracingulate gyri (ACG.R) and the right middle frontal gyrus (MFG.R); the FC between the PrCG.R and the right median cingulate and paracingulate gyri (DCG.R) exhibited enhanced; the OFC showed increased FC with MFG.R and the left inferior occipital gyrus (IOG.L). In PPD, GMV of DLPFC.L was positively correlated with EDPS scores (r = 0.409 p = 0.031), and FC of PrCG.R-DCG.R was positively correlated with EDPS scores (r = 0.483 p = 0.020).ConclusionStructural and functional damage of the DLPFC.L and OFC is associated with cognitive disorders and parenting behaviors in PPD, while structural abnormalities of the DLPFC.L and PrCG.R are involved in impaired executive function. The increased GMV of DLPFC.L may be a unique structural pathological mechanism of PPD related to the inability of PPD patients to withstand long-term parenting stress. These findings have important implications for understanding neural mechanisms in PPD

Recent Advances in Conjugated Polymers for Light Emitting Devices

A recent advance in the field of light emitting polymers has been the discovery of electroluminescent conjugated polymers, that is, kind of fluorescent polymers that emit light when excited by the flow of an electric current. These new generation fluorescent materials may now challenge the domination by inorganic semiconductor materials of the commercial market in light-emitting devices such as light-emitting diodes (LED) and polymer laser devices. This review provides information on unique properties of conjugated polymers and how they have been optimized to generate these properties. The review is organized in three sections focusing on the major advances in light emitting materials, recent literature survey and understanding the desirable properties as well as modern solid state lighting and displays. Recently, developed conjugated polymers are also functioning as roll-up displays for computers and mobile phones, flexible solar panels for power portable equipment as well as organic light emitting diodes in displays, in which television screens, luminous traffic, information signs, and light-emitting wallpaper in homes are also expected to broaden the use of conjugated polymers as light emitting polymers. The purpose of this review paper is to examine conjugated polymers in light emitting diodes (LEDs) in addition to organic solid state laser. Furthermore, since conjugated polymers have been approved as light-emitting organic materials similar to inorganic semiconductors, it is clear to motivate these organic light-emitting devices (OLEDs) and organic lasers for modern lighting in terms of energy saving ability. In addition, future aspects of conjugated polymers in LEDs were also highlighted in this review

Empirical study of the dilemma regarding preliminary proof of causality and methods used by victims in China's environmental health litigation

Environmental health incidents have occurred frequently in recent years; in China, however, litigation has not been effective in protecting the rights and interests of victims due to their heavy burden of proof. In order to mitigate the burden of proof for victims, the environmental judicature in China introduced the rule of inversion of burden of proof; this means that the victim only assumes the preliminary burden of proof, but in practice it has not been sufficient. Victims in environmental health litigation still face many difficulties in proving causality. Based on the statistical analysis of judicial big data, this paper demonstrates three dilemmas faced by victims. First, the preliminary burden of proof of causality has a high standard. Second, the victim's ability to produce evidence is low. Third, the casual relationship between pollution behaviors and health damage is difficult to identify. When examining the possible legal instruments, there are three aspects to the causes of these dilemmas: theory, judicial practice, and society. The theoretical aspect manifests as the differences between the rule of inversion of burden of proof and the presumption of causality; the practical aspect manifests as the lack of an identification system for personal injury; and the social aspect manifests as the victim's lack of economic, scientific, technological, and information resources, as well as the absence of assistance from government sectors and social organizations. Combining Chinese law with judicial practice, this paper proposes a solution to the dilemma of victims needing to prove causality in environmental health litigation. On the basis of clarifying the theoretical differences between the inversion of burden of proof and the presumption of causality, China should adhere to the rule of inversion of burden of proof, establish an identification system for personal injuries caused by environmental pollution, and use methods such as epidemiological causality, indirect counterevidence, and prima facie bewies. Furthermore, the full functions of the government and social organizations must be brought into play. This will not only help victims demonstrate causality, it can also help victims achieve equitable relief

A Performance Indicator Based Infill Criterion for Expensive Multi-/Many-objective Optimization

Qin S, Sun C, Liu Q, Jin Y. A Performance Indicator Based Infill Criterion for Expensive Multi-/Many-objective Optimization. IEEE Transactions on Evolutionary Computation. 2023:1-1.n surrogate-assisted multi-/many-objective evolutionary optimization, each solution normally has an approximated value on each objective, resulting in increased difficulties in selecting solutions for expensive objective evaluations due to complicated trade-off between different objectives and accumulated uncertainty in the approximation of the objective functions. Thus, it is highly challenging to design an efficient model management strategy for surrogate-assisted expensive multi-/many-objective optimization. In this paper, a surrogate model is built for each objective function, based on which a set of promising candidate solutions are found. Additionally, a Gaussian process model is constructed to approximate a newly designed performance indicator measuring both convergence and diversity properties of individual solutions. Finally, the solution of the found candidate solutions having the maximum expected improvement in terms of the performance indicator is selected for evaluation using the expensive objective functions. Comparative experiments are conducted on 3-, 5-, and 10-objective DTLZ, WFG, and MaF test functions, as well as two real-world applications. The experimental results show that the proposed method is competitive compared to five state-of-the-art surrogate-assisted evolutionary algorithms for expensive multi-/many-objective optimization

Study on the polymorphism of ITS in Osmanthus

In this study, ITS sequence was cloned respectively from 17 species of Osmanthus and sequenced. It was found that length of ITS sequence including 5.8S of 17 species ranged from 614bp to 619bp, 5.8S was composed of 163bp. Furthermore, ITS sequence of individuals species took on polymorphism, the similarity coefficient between ITS sequences of every species was 97.90%~100%, the minimum similarity coefficient appeared in O.reticulatus (97.90%~99.50%), and the maximum is shown in O.cooperi (99.70%~100%). 58 kinds of ITS sequences from 17 species were analyzed and discovered that the polymorphic ITS sequences from 12 species were respectively clustered together, but 3 kinds of ITS sequences from O.Venosus were not clustered together, thus apart from O.Venosus, any of ITS sequence clustered together from the other 16 species of Osmanthus all could stand for the feature of ITS sequence in every species. In addition, in the dendrogram, O.yunnanensis and O.attenuatus were clustered to be one group, O.americanus, O.matsumuraanus and O.delavayi were clustered to different groups, the other 12 species of were clustered together, which is partly identical with the viewpoint of traditional taxology about Osmanthus. Therefore, it might be feasible to analyze the sibship and phylogenetic relationships of Osmanthus by ITS