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Accurate machine learning models based on small dataset of energetic materials through spatial matrix featurization methods

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Journal of Energy Chemistry 2021年第12期30卷 364-375,I0009页

作者： Chao Chen Danyang Liu Siyan Deng Lixiang Zhong Serene Hay Yee Chan Shuzhou Li Huey Hoon Hng school of materials science and engineering Nanyang Technological University50 Nanyang AvenueSingapore 639798Singapore

A large database is desired for machine learning(ML) technology to make accurate predictions of materials physicochemical properties based on their molecular *** a large database is not available,the development of proper featurization method based on physicochemical nature of target proprieties can improve the predictive power of ML models with a smaller *** this work,we show that two new featurization methods,volume occupation spatial matrix and heat contribution spatial matrix,can improve the accuracy in predicting energetic materials' crystal density(ρ_(crystal)) and solid phase enthalpy of formation(H_(f,solid)) using a database containing 451 energetic *** mean absolute errors are reduced from 0.048 g/cm~3 and 24.67 kcal/mol to 0.035 g/cm~3 and 9.66 kcal/mol,*** leave-one-out-cross-validation,the newly developed ML models can be used to determine the performance of most kinds of energetic materials except *** ML models are applied to predict ρ_(crystal) and H_(f,solid) of CHON-based molecules of the 150 million sized PubChem database,and screened out 56 candidates with competitive detonation performance and reasonable chemical *** further improvement in future,spatial matrices have the potential of becoming multifunctional ML simulation tools that could provide even better predictions in wider fields of materials science.

关键词： Small database machine learning Energetic materials screening Spatial matrix featurization method Crystal density Formation enthalpy n-Body interactions

Single metal atom decorated photocatalysts:Progress and challenges

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Nano Research 2021年第4期14卷 934-944页

作者： Lei Zeng Can Xue school of materials science and engineering Nanyang Technological University50 Nanyang avenueSingapore 639798Singapore

Photocatalysis has attracted intense attention due to its potential to solve the energy resource problem and environmental *** single metal atom decorated photocatalysts as a rising star become more and more popular because of the unique advantages of superior catalytic activities and ultrahigh atom utilization *** key function of single metal atom catalysts in photocatalytic reactions is boosting surface redox reactions by utilizing photogenerated charges,and has been verified by various spectroscopic and microscopic ***,the activities of the single metal atoms highly depend on the binding environment in the host photocatalyst that affect the adsorption and activation of reactants as well as the reaction energy ***,this mini review summarizes recent progress on single metal atom decorated photocatalysts,and discusses the roles of the single metal atom catalysts in different types of host photocatalysts including organic,carbon-based and inorganic *** remaining challenges and future perspectives on the stability and activities of single atom catalysts in photocatalytic processes are elaborated in the *** believe that this mini review will provide valuable overview on synthetic methods of different single atom photocatalysts for researchers towards future development of highly efficient photocatalysts.

关键词： photocatalysis solar fuels hydrogen generation CO_(2)reduction artificial photosynthesis solar energy conversion

Equivalent protection factor of bi-layer ceramic metal structures

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Defence Technology（防务技术） 2022年第3期18卷 384-400页

作者： Govind Gour Sridhar Idapalapati Wei Liang Goh Xiao-peng Shi school of Mechanical&Aerospace engineering Nanyang Technological University50 Nanyang AvenueSingapore639798Singapore school of materials science&engineering Nanyang Technological University50 Nanyang AvenueSingapore639798Singapore

With increasing ballistic threat levels,there is ever more demand on developing ceramic armor designs with improved *** paper presents finite element simulations that investigate the performance of silicon carbide ceramic with steel 4340 backing material and titanium alloy,graphite as buffer layers when subjected to normal and oblique impacts by a tungsten alloy long rod projectile(LRP).Depth of penetration from experimental measurements is compared with simulations to confirm the validity of constitutive,failure model *** alloy cover plate and graphite interface weak layer laterally spread the impact shock away from the SiC tile and reduces the amplification of the stress accumulation at the front surface of the SiC *** dwelling time increases before it penetrates into ceramic ***,using AUTODYN®numerical simulations detailed parametric study is carried out to identify the minimum areal density armor for a given ballistic limit *** equivalent protection factor for the bi-layer armor is a simple function of the cosine of the angle of impact.

关键词： Ceramic armor Normal and NATO 60⁰impact Ballistic limit velocity Equivalent protection factor(EPF)

Comparative Study on the Corrosion Resistance of Al–Cr–Fe Alloy Containing Quasicrystals and Pure Al

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Journal of materials science & Technology 2016年第10期32卷 1054-1058页

作者： R.T.Li Vinod K.Murugan Z.L.Dong K.A.Khor school of Mechanical and Aerospace engineering Nanyang Technological University 50 Nanyang AvenueSingapore 639798 Singapore school of materials science and engineering Nanyang Technological University50 Nanyang Avenue Singapore 639798Singapore

Al-Cr-Fe alloy containing quasicrystals has been consolidated using spark plasma sintering（SPS）. Its corrosion resistance properties were comparatively investigated with pure Al by electrochemical methods in 3.5 wt% NaCl solution. Their corrosion current density was also compared with that of three commercial steels-316 stainless steel, AISI 440C stainless steel and AISI H13 tool steel. Al-Cr-Fe alloy exhibits nobler corrosion potential and evident passivation with a potential range of around 150 mV while no passivation of pure Al sample is seen. The corrosion resistance of Al-Cr-Fe alloy is less than that of pure Al, but is close to that of 316 stainless steel and superior to that of AISI 440C stainless steel and AISI H13 tool steel.

关键词： Quasicrystal Spark plasma sintering Microstructure Corrosion resistance

Versatile and scalable chemical vapor deposition of vertically aligned MoTe2 on reusable Mo foils

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Nano Research 2020年第9期13卷 2371-2377页

作者： Jinjun Lin Hong Wang Roland Yingjie Tay Hongling Li Maziar Shakerzadeh Siu Hon Tsang Zheng Liu Edwin Hang Tong Teo school of Electrical and Electronic engineering Nanyang Technological University50 Nanyang AvenueSingapore 639798Singapore Temasek Laboratories@NTU 50 Nanyang AvenueSingapore 639798Singapore school of materials science and engineering Nanyang Technological University50 Nanyang AvenueSingapore 639798Singapore

Layered MoTe2 has shown great promises for optoelectronics and energy-storage applications due to its exceptional optical and electrochemical *** date,considerable efforts have been devoted to fabricating layered MoTe2 with lateral orientation by means of mechanical/chemical exfoliation and chemical vapor deposition(CVD)*** compared to its horizontal counterparts,vertically aligned MoTe2 with higher density of active edge sites is expected to possess unique optoelectronic and electrochemical properties,while which has not been reported *** this work,we report a versatile and scalable CVD growth of vertically aligned MoTe2 with length of up to〜7.5 fjm on Mo ***,the dominant phase of the vertically aligned MoTe2 can be tuned from 2H to 1T’by increasing the growth temperature from 630 to *** to the weak interaction between the as-grown MoTe2 and Mo foil,the as-grown MoTe2 can be easily detached from the Mo *** in turn enabled economic reuse of the Mo foil for multiple ***,the vertical growth of the MoTe2 is proposed to be caused by the internal strain generated during tellurization of Mo ***,the as-grown MoTe2 can also be directly dispersed in solvent to produce high-quality MoTe2 *** versatility of this growth strategy was further demonstrated by fabricating other vertically aligned transition metal chalcogenides(TMDs)such as TaTe2 and ***,this work paves the path towards achieving unique TMDs structures to enable high-performance optoelectronic and electrochemical devices.

关键词： molybdenum dltelluride chemical vapor deposition vertical growth reusable substrate

Additive manufacturing of composite materials and functionally graded structures using selective heat melting technique

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Journal of materials science & Technology 2020年第12期47卷 243-252页

作者： Kalaimani Markandan Ruijing Lim Pawan Kumar Kanaujia Ian Seetoh Muhammad Raziq bin Mohd Rosdi Zhi Huey Tey Jun Seng Goh Yee Cheong Lam Changquan Lai Temasek Laboratories Nanyang Technological University50 Nanyang Drive637553Singapore school of Physical&Mathematical sciences Nanyang Technological University21 Nanyang Link637371Singapore school of Mechanical&Aerospace engineering Nanyang Technological University50 Nanyang Avenue639798Singapore school of materials science&engineering Nanyang Technological University50 Nanyang Avenue639798Singapore

The feasibility of using selective heat melting(SHM) to fabricate composite materials and functionally graded structures was *** report,for the first time,the successful 3 D printing of copper(Cu)-polyethylene(PE) composite,iron(Fe)-polyethylene(PE) composite and functionally graded CuO foams using the SHM *** was found that a low feed rate,high airflow rate and high airflow temperature were required for efficient delivery of heat from the emitted hot air to the powder bed,so that the PE binder particles can melt and form dense composites with smooth *** best mechanical properties were exhibited by composites with 80 vol.% PE,as lower PE concentrations led to deficient binding of the metal particles,while higher PE concentrations meant that very few metal particles were available to strengthen the *** strength exhibited by Cu-PE composites was comparable to engineering plastics such as polycarbonate,with the added advantage of being electrically *** average conductivity of the samples,0.152±0.28 S/m,was on par with physically crosslinked graphene *** subjecting a Cu-PE composite,with Cu concentration graded from 10 vol.% to 30 vol.%,to a high temperature debinding and sintering treatment in air,CuO foam with graded porosity can be *** CuO foam was observed to fail in a layer-by-layer manner under mechanical compression,which is a characteristic of functionally graded *** study shows that,compared to existing 3 D printing techniques,SHM can be cheaper,have wider material compatibility,occupy a smaller footprint and potentially induce less residual stresses in the fabricated ***,it could be a valuable complement to current additive manufacturing techniques for fabricating mechanically strong composite materials and functionally graded structures.

关键词： Selective heat melting Functionally graded materials Additive manufacturing Multimaterial

A new insight into electrochemical detection of eugenol by hierarchical sheaf-like mesoporous NiCo2O4

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Nano Research 2015年第8期8卷 2636-2645页

作者： Mylamparambil Udayan Anu Prathap Chao Wei Shengnan Sun Zhichuan J. Xu school of materials science and engineering Nanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore

NiCo2O4 nanosheets with sheaf-like nanostructure morphologies have been synthesized by a facile one-step hydrothermal reaction followed by annealing treatment. Impressively, the NiCo2O4 nanosheets exhibit rapid detection of eugenol. The linear range of detection is from 1-500μM, and the limit of detection is 5.4 μM. The NiCo2O4 modified electrode demonstrated high sensitivity, good repeatability and reproducibility, and long-term stability （7% decrease in response over 30 days）. Based on this work, an electrochemical reaction mechanism for eugenol oxidation was proposed, and in addition, the NiCo2O4 modified electrode was successfully employed for the analysis of eugenol in medicative balm samples. Recovery values for eugenol in medicative balm samples were in the range 98.7%-105.5%.

关键词： NiCo2O4 nanosheets eugenol determination electrocatalysis electrochemical mechanism real sample analysis

Synthesis, properties and applications of one- and two- dimensional gold nanostructures

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Nano Research 2015年第1期8卷 40-55页

作者： Xun Hong Chaoliang Tan Junze Chen Zhichuan Xu Hua Zhang school of materials science and engineering Nanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore

The controlled synthesis of gold nanocrystals has been the subject of intensive studies for decades because the properties and functions of gold nanomaterials are highly dependent on their particle size, shape, and dimensionality. Especially, anisotropic gold nanocrystals, such as nanowires, nanobelts, nanoplates and nanosheets, have attracted much attention due to their striking properties and promising applications in electronics, catalysis, photonics, sensing and biomedicine. In this review, we will summarize the recent developments of one- dimensional （1D） and two-dimensional （2D） gold nanostructures. Various kinds of synthetic methods for preparation of these 1D and 2D gold nanocrystals will be described. Moreover, we will also briefly introduce the properties and potential applications of these 1D and 2D gold nanocrystals.

关键词： gold nanostructures nanowires nanobelts nanoplates nanosheets

Self-powered pressure sensor for ultra-wide range pressure detection

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Nano Research 2017年第10期10卷 3557-3570页

作者： Kaushik Parida Venkateswarlu Bhavanasi Vipin Kumar Ramaraju Bendi Pooi See Lee school of materials science and engineering Nanyang Technological University Nanyang Avenue 639798 Singapore

The next generation of sensors should be self-powered, maintenance-free, precise, and have wide-ranging sensing abilities. Despite extensive research and development in the field of pressure sensors, the sensitivity of most pressure sensors declines significantly at higher pressures, such that they are not able to detect a wide range of pressures with a uniformly high sensitivity. In this work, we demonstrate a single-electrode triboelectric pressure sensor, which can detect a wide range of pressures from 0.05 to 600 kPa with a high degree of sensitivity across the entire range by utilizing the synergistic effects of the piezoelectric polarization and triboelectric surface charges of self-polarized polyvinyldifluoride-trifluoroethylene （P（VDF-TrFE）） sponge. Taking into account both this wide pressure range and the sensitivity, this device exhibits the best performance relative to that of previously reported self-powered pressure sensors. This achievement facilitates wide-range pressure detection for a broad spectrum of applications, ranging from simple human touch, sensor networks, smart robotics, and sports applications, thus paving the way forward for the realization of next-generation sensing devices. Moreover, this work addresses the critical issue of saturation pressure in triboelectric nanogenerators and provides insights into the role of the surface charge on a piezoelectric polymer when used in a triboelectric nanogenerator.

关键词： self-powered triboelectric piezoelectric nanogenerator pressure sensor