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1

Computational Investigation on the Structure and Performance of Novel 4,7-dinitro-furazano-[3,4-d]-pyridazine Derivatives

Wang K., Shu Y., Liu N., Ding X., Wu Z., Lu Y.

Central European Journal of Energetic Materials

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2017

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Vol. 14, no. 1

26--46

EN

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.

2

Coating of LiBH4 and Its Effect on the Decomposition of RDX and AP

Ding X., Shu Y., Chen Z., Liu N., Gou B., Zhang J., Wu M., Xie G., Dang T.

Central European Journal of Energetic Materials

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2017

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Vol. 14, no. 1

134--151

EN

The novel fuel additive LiBH4 was introduced as an energetic component for its outstanding hydrogen content, perfect burning performance and high reactivity. In order to limit the hygroscopicity and to improve the stability in the air, LiBH4 was coated on the surface with wax and polyester carbonate. The final product was characterized by scanning electron microscopy (SEM), X-ray photoelectron energy spectroscopy (XPS) and Raman spectroscopy, while the stability in air was investigated by regular checking of variations in weight. The results show that a uniform coating layer was formed on the surface of the LiBH4, and the coverage was estimated from the boron content as approximately 82%. A healing effect was confirmed on defective surfaces exposed to air; the coating layer improves the relative stability by 50.7%. Furthermore, LiBH4 as an additive to promote the thermal decomposition of 1,3,5-trinitro-1,3,5-trazinane (RDX) and ammonium perchlorate (AP) was explored by differential scanning calorimetry (DSC), in which the catalytic effects of pure LiBH4 and coated LiBH4 were compared, and indicated that the coating does not decrease the reactivity of LiBH4. It is suggested that surface coating with some inert materials is a simple and effective method for improving the storage and performance of LiBH4, while ensuring its reactivity.

3

Electrical Properties of PPy-Coated Conductive Fabrics for Human Joint Motion Monitoring

Hu J., Zhang X., Li G., Yang X., Ding X.

Autex Research Journal

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2016

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Vol. 16, no. 1

7--12

EN

Body motion signals indicate several pathological features of the human body, and a wearable human motion monitoring system can respond to human joint motion signal in real time, thereby enabling the prevention and treatment of some diseases. Because conductive fabrics can be well integrated with the garment, they are ideal as a sensing element of wearable human motion monitoring systems. This study prepared polypyrrole conductive fabric by in situ polymerization, and the anisotropic property of the conductive fabric resistance, resistance–strain relationship, and the relationship between resistance and the human knee and elbow movements are discussed preliminarily.

4

Supplier Selection for Mixed-Model Production: A Case Study from the Apparel Industry

Stojanov T, Ding X

Fibres & Textiles in Eastern Europe

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2015

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Vol. 23, no. 1 (109)

8--12

EN

The mass-customization trend as flexible production philosophy has been adopted by many industries as a reaction to the fast changing customer demand environment. In relation to that mixed-model production (MMP) is a possibility for increasing flexibility, especially in the assembly department. However, many apparel companies have failed in their transition from traditional manufacturing to new, flexible manufacturing, which makes it difficult for them to be selected as suppliers who are capable of MMP. In most of the studies that have been done before, the problem of supplier selection was based on productivity and cost as the main selection criteria. As an alternative solution this research presents a new group of criteria for supplier selection with respect to the goal of MMP. The methodology of combining the analytical hierarchy process (AHP) with the support of the commercial software package Expert Choice and cluster analysis (CA) is proposed in this study. The results obtained present a new group of criteria, ranked by their importance, that the supplier needs to fulfil in order to be selected for MMP. Furthermore the large number of available suppliers was grouped into four clusters based on their similar characteristics by using CA. Finally the most acceptable cluster for MMP was selected using AHP. The methodology presented in this study can support the apparel industry in better decision making in the process of selecting the best group of suppliers for mixed-model production.

PL

W wielu przemysłach wprowadzono system zindywidualizowanej produkcji masowej jako reakcję na szybko zmieniające się wymagania konsumentów. Dotychczas selekcja dostawców oparta była na produktywności i analizie kosztów. Ten artykuł prezentuje alternatywne rozwiązanie z wyborem nowej grupy kryteriów. Przedstawiono metodologię połączenia metody hierarchicznej analizy z pakietem Expert Choice i analizą klastrów. W proponowanej metodzie dostawcy zostali podzieleni na cztery klastry na podstawie podobieństwa charakterystyk. W efekcie najbardziej akceptowalny klaster zostaje wybrany przy zastosowaniu metody hierarchicznej analizy. Metoda ta może wspomóc prawidłowe funkcjonowanie przemysłu odzieżowego.

5

Internal Friction of Phase Transformations Observed Around Room Temperature in Ga-In-Sn Eutectic Alloys

Jin M., Li Q., Ying R., Lu X., Jin X., Ding X.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 3A

2097--2100

EN

The phase transformation phenomena in eutectic Ga-In-Sn alloys around room temperature are studied by thermal analysis, internal friction, and in-situ XRD methods. The results show that in addition to the solidification transformation, a novel the so-called ‘pre-solidification’ phase transition, demonstrating first-order feature, is observed prior to the crystallization during cooling. The internal friction increases when the ‘pre-solidification’ effect occurs. The shear modulus increases until crystallization. An internal friction peak is attributed to the melting process observed during heating. The mechanism of the ‘pre-solidification’ transformation in Ga-In-Sn eutectic alloy is discussed.

PL

Zjawiska przemian fazowych w eutektycznych stopach Ga-In-Sn, około temperatury pokojowej, badane są metodami analizy termicznej, tarcia wewnętrznego i XRD in-situ. Wyniki pokazują, że w dodatku do przemiany krzepnięcia, nowa przemiana tzw. „wstępne krzepnięcie”, o charakterze przemiany pierwszego rzędu, obserwowana jest przed krystalizacją podczas chłodzenia. Tarcie wewnętrzne zwiększa się, gdy występuje „wstępnie krzepnięcie”. Moduł sprężystości poprzecznej zwiększa się aż do krystalizacji. Wewnętrzny pik tarcia przypisany jest do topienia obserwowanego podczas ogrzewania. Omówiono mechanizm przemiany „wstępnego krzepnięcia” w eutektycznym stopie Ga-In-Sn.

6

An unconditionally positive and global stability preserving NSFD scheme for an epidemic model with vaccination

Ding D., Ma Q., Ding X.

International Journal of Applied Mathematics and Computer Science

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2014

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Vol. 24, no. 3

635--646

EN

In this paper, a NonStandard Finite Difference (NSFD) scheme is constructed, which can be used to determine numerical solutions for an epidemic model with vaccination. Here the NSFD method is employed to derive a set of difference equations for the epidemic model with vaccination. We show that difference equations have the same dynamics as the original differential system, such as the positivity of the solutions and the stability of the equilibria, without being restricted by the time step. Our proof of global stability utilizes the method of Lyapunov functions. Numerical simulation illustrates the effectiveness of our results.

7

Minimal Description and Maximal Description in Covering-based Rough Sets

Wang Z., Shu L., Ding X.

Fundamenta Informaticae

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2013

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Vol. 128, nr 4

503--526

EN

Rough set theory is an important technique in knowledge discovery in databases. In covering-based rough sets, seven types of rough set models were established in recent years. This paper defines the concept of maximal description of an element, and further explores the properties and structures of several types by means of the concepts of maximal description and minimal description. Finally, we study the relationship between covering-based rough sets and the generalized rough sets based on binary relation.

8

Interval Multi-objective Optimization Design Based on Physical Programming

Zhang X., Sun W., Huo J., Ding X.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 7b

379--381

EN

This paper develops a new effective and computationally-efficient approach for design optimization, hereby entitled interval physical programming optimization design. In view of the limitation that weights without physical meaning are required to be provided in traditional evaluation methods, physical programming is used in multi-objective optimization problem. Considering the uncertain factors in manufacture process and operation environment, the interval physical programming model (IPP) is improved. Decision-makers only need to set the boundary values of each preference range，thereby the interval objective of selected projects are computed with the IPP model. To address the existing problems in structure optimal design, the manufacturing tolerances of each dimension are defined as the region limits of design variables. The example of multi-objective optimization design of a pinned-pinned sandwich-beam demonstrates the effectiveness and practicality of the proposed method.

PL

W artykule zaproponowano nowy skuteczny model optymalizacji projektowania nazwany: interval physical programming optimization design. Model wykorzystuje problem optymalizacji wieloobiektowej uwzględniając niepewność w procesie produkcji i warunki środowiskowe.

9

No evidence for a positive response of biomass production to species diversity in an experimental grassland

Ding X., Wang Y., Yu S.

Polish Journal of Ecology

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2012

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Vol. 60, nr 4

667--675

EN

Plant diversity is generally thought to enhance productivity, driven by either (1) chance inclusion of highly productive species in more diverse communities or (2) niche-based resource acquisition with competitive interactions increasing resource use efficiency. Here, we ask whether weeding, as employed in most experiments to date, might contribute to the positive diversity-productivity relationship reported for many grasslands. Using all 82 species from our local pool, we constructed 357 experimental grassland plots (2 × 4 m each), arranged as a completely randomized experiment in an arable field prepared to minimize existing seed bank. The plots were sown to vary species richness (1, 2, 4, 6, 8, 10, 15, 20, 25, 30, 35 or 40 species) and were maintained under both ambient conditions and experimental drought. A single monoculture plot was maintained for all 82 species, and each of the other eleven species richness levels was replicated 25 times. Plots were maintained strictly without weeding, and aboveground biomass was measured at 17, 19, 27 and 29 months after the start of this experiment. No single measure of biodiversity was significantly correlated with productivity consistently across all four sampling periods. Furthermore, there were only weak overall effects of six biodiversity variables (the species richness planted, observed, and sampled; Shannon diversity, effective species richness and evenness in the sampled area) on productivity under either precipitation treatment. Regression analysis identified no equation that used a consistent subset of the biodiversity measures as predictors. In view of these transient and insubstantial effects, results from previous experiments that employed weeding treatments are suspect as tests of the hypothesis that biodiversity has positive effects on productivity.

10

Transverse vibration of papermaking felt

Zheng P., Ding X., Yang J., Chen R.

Fibres & Textiles in Eastern Europe

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2010

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Vol. 18, no. 3 (80)

106--108

EN

The papermaking felt of high-speed papermaking machine vibrates seriously in a transverse direction. In this study, the transverse vibration of papermaking felt was analysed mechanically with respect to flexural rigidity, and a model was developed. The analytical resolution is obtained by the separation variable method. The result shows that it is a sinusoidal steady-state response. The natural frequency is calculated by the principle of free vibration. The flexural rigidity and density of papermaking felt are the main factors influencing its natural frequency. The validity of the model is verified theoretically and experimentally. The amplitude of the transverse vibration was tested by an optical noncontact measuring system. The amplitude-frequency characteristic curve shows that the natural frequency measured agrees well with the theoretical one.

PL

Filc suszący w maszynach papierniczych o dużej prędkości produkcyjnej wykazuje znaczne wibracje w kierunku poprzecznym do przebiegu formowanej taśmy papieru. Badano poprzeczne drgania w maszynach papierniczych analizując zależności mechaniczne z uwzględnieniem sztywności zginania i opracowano model matematyczny. Analityczne rozwiązanie zostało uzyskane metodą separacji zmiennych. Wyniki wskazują, że otrzymuje się sinusoidalny stan ustalony jako odpowiedz układu na wystąpienie zakłócenia. Częstotliwość drgań własnych obliczono na podstawie zależności opisanych dla drgań swobodnych. Głównymi czynnikami wpływającymi na częstotliwość drgań własnych są sztywność zginania i gęstość filcu suszącego. Prawidłowość modelu została zweryfikowana teoretycznie i eksperymentalnie. Amplitudę drgań poprzecznych badano doświadczalnie za pomocą bezdotykowego układu optycznego. Charakterystyki amplitudowo-częstotliwościowe układu wskazują, że pomierzona częstotliwość drgań własnych jest zgodna z obliczeniami teoretycznymi.