Autor: Shu, X. - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Rejection of harmonic and transient disturbances of a smart structure with piezoelectric actuators
Autorzy:: Duarte, F.
Ballesteros, P.
Shu, X.
Bohn, C.
Tematy:: active vibration control
gain scheduling
linear parameter-varying systems
piezoelectric actuators
aktywne tłumienie drgań
harmonogramowanie wzmocnienia
liniowy układ niestacjonarny
aktuatory piezoelektryczne; Pokaż więcej
Wydawca:: Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Powiązania:: https://bibliotekanauki.pl/articles/368993.pdf Link otwiera się w nowym oknie
Opis:: Light flexible structures are easily prone to vibrate due to external forces or due to forces generated in the inner structure. This situation is common in machinery or mechanical structures with rotational devices. The unwanted vi-bration of such structures can be compensated with the addition of piezoelectric actuators for active vibration control (AVC). The rejection of harmonic disturbances is frequently done with controllers based on the internal model principle. The goal of this research is to reduce the effect of harmonic disturbances with known (measured) time-varying fre¬quencies acting on a system as well as to increase the damping of the system for the transient response (first mode of vibration). The experimental setup is made up of a slender aluminium flexible beam, a pair of piezoelectric actuators, an accelerometer and two DC motors, as well as the data acquisition and signal conditioning equipment. The harmonic disturbance is generated by DC motors. The control design utilizes an augmented description of the plant. The plant including the disturbance is modelled as a polytopic linear parameter-varying (pLPV) system. An observer-based gain-scheduling controller is calculated based on quadratic stability and the stability is guaranteed for the specified range ofvariation of the scheduling parameters, also restriction in the performance is introduced in the sense of the H2-norm. Experimental results show very good disturbance cancellation.
Lekkie konstrukcje są podatne na drgania wzbudzane przez wymuszenia zewnętrzne oraz siły występujące wewnątrz układu. Drgania tego typu konstrukcji mogą być zredukowane przy zastosowaniu aktuatorów piezoelektrycznych i układów aktywnej regulacji. Układy eliminacji drgań często wykorzystują regulatory zaprojektowane przy wykorzysta¬niu modelu obiektu. Celem obecnych badań była redukcja wpływu harmonicznie zmiennych parametrów układu oraz zwiększenie tłumienia drgań nieustalonych. Obiekt sterowania został zamodelow any jako liniowy układ niestacjonarny. Układ regulacji uwzględniający obserwator stanu został zaprojektowany przy wykorzystaniu normy H2. Przeprowadzono weryfikację doświadczalną zaproponowanej metody. W skład stanowiska doświadczalnego wchodziły: podatna bel¬ka wykonana z aluminium, para aktuatorów piezoelektrycznych, akcelerometr, dwa silniki prądu stałego oraz układ akwizycji danych i ich kondycjonowania. Zaburzenie harmoniczne było generowane przez silniki prądu stałego. Wyniki badań doświadczalnych potwierdziły dużą skuteczność zaproponowanej metody redukcji drgań.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Synthesis and Characterization of PolyNIMMO-HTPB-polyNIMMO Triblock Copolymer as a Potential Energetic Binder
Autorzy:: Wang, X.
Shu, Y.
Lu, X.
Mo, H.
Xu, M.
Tematy:: triblock copolymer
cationic ring opening polymerization
polymer
DSC; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/358529.pdf Link otwiera się w nowym oknie
Opis:: Triblock copolymer polyNIMMO-HTPB-polyNIMMO was synthesized by cationic ring opening polymerization of NIMMO (3-nitratomethyl-3-methyloxetane) in the presence of hydroxyl-terminated polybutadiene catalyzed by BF3·OEt2. The polymer was characterized by FT-IR, 1H NMR, 13C NMR spectroscopy, and GPC. DSC was used to investigate the thermal behaviour of the triblock copolymer and its exothermic decomposition peak was found to be at 215 °C. All of the results indicated that the triblock copolymer polyNIMMO-HTPB-polyNIMMO might serve as a potential energetic propellant binder.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Soft anatomy of the Early Cambrian arthropod Isoxys curvirostratus from the Chengjiang biota of South China with a discussion on the origination of great appendages
Autorzy:: Fu, D.-J.
Zhang, X.-L.
Shu, D.-G.
Wydawca:: Polska Akademia Nauk. Instytut Paleobiologii PAN
Powiązania:: https://bibliotekanauki.pl/articles/22449.pdf Link otwiera się w nowym oknie
Opis:: An updated reconstruction of the body plan, functional morphology and lifestyle of the arthropod Isoxys curvirostratusis proposed, based on new fossil specimens with preserved soft anatomy found in several localities of the Lower Cambrian Chengjiang Lagerstätte. The animal was 2–4 cm long and mostly encased in a single carapace which is folded dorsally without an articulated hinge. The attachment of the body to the exoskeleton was probably cephalic and apparently lacked any well−developed adductor muscle system. Large stalked eyes with the eye sphere consisting of two layers (as corneal and rhabdomeric structures) protrude beyond the anterior margin of the carapace. This feature, together with a pair of frontal appendages with five podomeres that each bear a stout spiny outgrowth, suggests it was raptorial. The following 14 pairs of limbs are biramous and uniform in shape. The slim endopod is composed of more than 7 podomeres without terminal claw and the paddle shaped exopod is fringed with at least 17 imbricated gill lamellae along its posterior margin. The design of exopod in association with the inner vascular (respiratory) surface of the carapace indicates I. curvirostratus was an active swimmer. Morphological comparisons demonstrate that species of Isoxys were diverse in feeding habits and occupied a very broad morphospace, i.e., carapace bivalved or a single shield, the pre−oral limbs antenniform or modified into great appendages, the succeeding endopods slim or stout. This casts doubt on the current taxonomy that assigns all species to a single genus, and on any presumed lifestyle of Isoxys extrapolated to the generic level. Finally, since I. curvirostratus and I. acutangulus carry a pair of great appendages, Isoxys has recently been placed into the great appendage arthropods. Such placement might be inadequate because the homology of the great appendages can not be established.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Soft-tissue preservation in the Lower Cambrian linguloid brachiopod from South China
Autorzy:: Zhang, Z
Han, J.
Zhang, X.
Liu, J.
Shu, D.
Tematy:: Lingulellotreta malongensis
Chengjiang Lagerstatte
soft tissue preservation
lophophore
brachiopod
linguloid brachiopod
China
Linguloidea
gastrointestinal tract
Cambrian
Lower Cambrian
paleontology; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Paleobiologii PAN
Powiązania:: https://bibliotekanauki.pl/articles/20001.pdf Link otwiera się w nowym oknie
Opis:: The organization of the lophophore and the digestive system are recognized as two of the diagnostic characters in the definition of higher brachiopod taxa, and hence play a major role in their phylogenetic analysis, their structure, however, is very rarely fossilized. Here we describe and interpret specimens of the brachiopod Lingulellotreta malongensis, from the Lower Cambrian Chengjiang Lagerstätte (South China), one of the earliest known taxa of the Lingulellotretidae, in which lophophores and intact, U−shaped digestive tracts are extraordinarily well−preserved. The lophophore, with clearly preserved tentacles, corresponds to an early spirolophe developmental stage. The digestive tract consists of a mouth, esophagus, distended stomach, intestine and an anterior anus, and differs from that of the Chengjiang obolid Lingulella chengjiangensis by the presence of the dilated stomach and by the absence of a looped intestine as in Lingula. In addition, the relative sizes of the mantle and visceral cavities of Lingulellotreta malongensis also are described. These fossils demonstrate that by the Atdabanian brachiopods had already possessed advanced features, and suggest that a lophophore and a U−shaped intestine with an anterior anus are brachiopod plesiomorphies.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Trunk ornament on the palaeoscolecid worms Cricocosmia and Tabelliscolex from the Early Cambrian Chengjiang deposits of China
Autorzy:: Han, J
Liu, J.
Zhang, Z.
Zhang, X.
Shu, D.
Tematy:: Tabelliscolex hexagonus
Palaeoscolecida
Priapulida
Chengjiang deposit
Cricocosmia jinningensis
trunk ornament
fossil worm
China
Early Cambrian
Cambrian
Lower Cambrian
paleontology; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Paleobiologii PAN
Powiązania:: https://bibliotekanauki.pl/articles/23260.pdf Link otwiera się w nowym oknie
Opis:: Cricocosmia jinningensis, one of the most abundant palaeoscolecid worms from the Lower Cambrian Chengjiang deposits of south China, was originally described as bearing double longitudinal rows of lateral conical sclerites on the trunk. New observation reveals that the ventral trunk bears an additional set of ventral sclerites while the lateral sclerites display a tubercle−bearing (inner surface) and net−like (outer surface) microstructure similar to that of Tabelliscolex hexagonus. These findings mean that: (1) Cricocosmia shows a dorso−ventral and antero−posterior differentiation in trunk ornament; (2) as seen from the microstructure, Cricocosmia is close to Tabelliscolex hexagonus, supporting the idea that lobopodians and arthropods, both of which show an upper capping layer in the outer sclerites, are more closely related than the palaeoscolecidans; and (3) the similarities among the scalids, pharyngeal teeth and the trunk spines of palaeoscolecidans are superficial. Tabelliscolex maanshanensis sp. nov., characterized by an inner concentric circlet of laminae in each tubercle of the lateral trunk plate, is proposed herein. Element mapping reveal that four known pathways of preservation can be found co−occurring in a single specimen of Cricocosmia or Tabelliscolex, which sheds new light on the preservation of the Chengjiang fossils.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: The lobopod Onychodictyon from the Lower Cambrian Chengjiang Lagerstatte revisited
Autorzy:: Liu, J
Shu, D.
Han, J.
Zhang, Z.
Zhang, X.
Tematy:: Yunnan
antenna
paleontology
Chengjiang Lagerstatte
Lobopodia
Arthropoda
lobopod
Cambrian
Lower Cambrian; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Paleobiologii PAN
Powiązania:: https://bibliotekanauki.pl/articles/21235.pdf Link otwiera się w nowym oknie
Opis:: Onychodictyon ferox, from the Lower Cambrian Chengjiang Lagerstätte, is a worm−like armored lobopod with 10 pairs of dorsal plates and a pair of probable sensory appendages (“antennae”). Newly discovered complete specimens show that Onychodictyon is represented by two species: O. ferox with a “head” bearing a pair of dorsal “antennae” and a trunk with 11 pairs of limbs, whereas O. gracilis has a blunt anterior end without any appendages and a trunk with 12 pairs of limbs. Because of the close resemblance of the “antennae” of O. ferox and those of the lobopod Miraluolishania, they are considered to be homologous structures. The “antennae” of Cambrian lobopodians are proposed to be homologous with the arthropod antennulae.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: A large xenusiid lobopod with complex appendages from the Lower Cambrian Chengjiang Lagerstatte
Autorzy:: Liu, J
Shu, D.
Han, J.
Zhang, Z.
Zhang, X.
Tematy:: Chengjiang Lagerstatte
Lobopodia
China
arthropod
Jianshanopodia decora
large lobopod
lobopod
body length
Arthropoda
Xenusiidae
Cambrian
paleontology
Lower Cambrian; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Paleobiologii PAN
Powiązania:: https://bibliotekanauki.pl/articles/21541.pdf Link otwiera się w nowym oknie
Opis:: A large lobopod, Jianshanopodia decora gen. et sp. nov., with body length (excluding appendages) about 220 mm from the Lower Cambrian Haikou section, near Kunming, Yunnan, southwest China, shows a mixture of characters, including features of the lobopod Xenusion Pompeckj, 1927, e.g., a large cylindrical body with annulations, stout and strong lobopod appendages each bearing bases of serial tubercles, and of Aysheaia Walcott, 1911, i.e., a pair of large frontal appendages. This suggests that the new genus might be a connecting link between Xenusion and Aysheaia. Besides, Jianshanopodia shares some features with the Early Cambrian stem group arthropod Pambdelurion Budd, 1997, and Kerygmachela Budd, 1993, e.g., the pairs of mid−gut diverticula, the possible presence of tail fan, the mouth cone, the frontal pharyngeal structures and the pharynax are surrounded by the bases of the large frontal appendages. However, compared with a series of segmentally arranged, imbricating, paddle−shaped, movable lateral flaps of both Pambdelurion and Kerygmachela, Jianshanopodia possesses distinct complex appendages with tree−like or lamellate branches. The discovery of this rare transitional form not only throws new light on the early diversification of lobopods, and may also have significance with respect to the origin of arthropods.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Computational Investigation on the Structure and Performance of Novel 4,7-dinitro-furazano-[3,4-d]-pyridazine Derivatives
Autorzy:: Wang, K.
Shu, Y.
Liu, N.
Ding, X.
Wu, Z.
Lu, Y.
Tematy:: 4,7-dinitro-furazano-[3,4-d]-pyridazine
heat of formation
density
detonation performance
bond dissociation energy; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/358090.pdf Link otwiera się w nowym oknie
Opis:: Seven novel energetic 4,7-dinitro-furazano-[3,4-d]-pyridazine derivatives were designed, and their optimized structures and performances were studied by density functional theory (DFT) at B3LYP/6-311g(d,p) level. The detonation performances were estimated by the Kamlet-Jacobs equations. The results show that these compounds have high crystal densities (1.818-1.925 g·cm−3), detonation velocities (8.51-9.56 km·s−1) and detonation pressures (32.28-41.70 GPa). The bond dissociation energies (BDEs) of the weakest bond (N–O bond) vary from 70.889 kJ·mol−1 to 173.283 kJ·mol−1, and some of them exhibit higher BDEs than that of RDX (N–NO2 bond, 149.654 kJ·mol−1) and HMX (N–NO2 bond, 154.905 kJ·mol−1). M4 and M5 exhibit similar and higher detonation performance than RDX (8.81 km·s−1, 34.47 GPa). The detonation performance of M7 (9.56 km·s−1, 41.70 GPa) even surpasses that of HMX (9.10 km·s−1, 39.00 GPa). Otherwise, the specific impulse values of M1-M7 (266-279 s) outperform HMX (266 s) by 0-13 s, which indicates that M1-M7 may show better performance as monopropellants. It is concluded that density, heat of formation, stability, detonation performance and specific impulse of the designed compounds depend on the position and number of the N→O oxidation bonds.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: The Reinforcement of the TNT System by a Newly-designed GAP-based Polyurethane-Urea: a Molecular Simulation Investigation
Autorzy:: Qian, W.
Shu, Y.
Ma, Q.
Li, H.
Wang, S.
Chen, X.
Tematy:: TNT
GAP
polyurethane-urea
inter-molecular interaction
mechanical properties; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/358512.pdf Link otwiera się w nowym oknie
Opis:: A glycidyl azide (GAP)-based polyurethane-urea (PUU) modifier used in the 1,3,5-trinitrotoluene (TNT)-based composite explosive was investigated by molecular simulation. Inter-molecular interactions were investigated using quantum chemistry calculation on the dimer of TNT and GAP-PUU, and attractive forces were found between the two molecules. The cohesive energy densities and the solubility parameters were obtained through molecular dynamics simulations combined with thermodynamic calculations on the TNT and GAP-PUU amorphous cell models, and the miscibility of the modifier in molten TNT was predicted to be good. The interaction energies and the mechanical properties were then obtained by molecular simulations and mechanical calculations on the solid-phase models of the GAP-PUU with TNT along three crystalline directions, and an improvement in the mechanical properties was predicted.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Phase Diagrams of the MeNQ/HN and HN/NQ Binary Systems
Autorzy:: Tian, M.-M.
Li, H.-R.
Chen, L.
Ju, X.
Shu, Y.-J.
Tematy:: phase diagram
binary system
eutectic
DSC
XRD; Pokaż więcej
Wydawca:: Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Powiązania:: https://bibliotekanauki.pl/articles/358436.pdf Link otwiera się w nowym oknie
Opis:: An equation for a binary phase diagram with two eutectic points was deduced from the Van’t Hoff equation. The melting points of hydrazinium nitrate/ nitroguanidine (HN/NQ) samples with different ratios, ranging from 0 to 1 mole fraction, were explored by differential scanning calorimetry (DSC). The results revealed the presence of two eutectic points in the phase diagram of the HN/NQ binary system. The dependence of temperature on the composition (T-X phase diagram) of HN/NQ was depicted based on the equation described by the DSC data. The phase diagram of MeNQ/HN, with only one eutectic point was constructed by substituting experimental data of the compositions and their corresponding temperatures into the Van’t Hoff equation. The phase diagram with two or more eutectic points indicated the formation of new stable compounds with appropriate ratios of the two components; no new substance appeared in the system with only one eutectic point. Thus, the HN/NQ binary system showed the presence of a new substance, which is probably the HN/NQ co-crystal. No new substance was detected in the MeNQ/HN binary system. The results of the X-ray diffraction patterns agree with the findings from the phase diagrams.
Dostawca treści:: Biblioteka Nauki

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