bluuebunny/crossref_metadata_2025 huggingface dataset:
Absolute total electron detachment and relative ionisation cross sections for O2
− collisions with O2 in the energy range (10–1500 eV)
Authors: Guerra Carlos , Lozano Ana I , Mendes Mónica F , Kumar Sarvesh , Oller Juan C , Limão-Vieira Paulo , García Gustavo
Published: January 2022

Absolute total electron detachment cross for O2
− collisions with O2 are reported for impact energies ranging from 10 to 1600 eV as measured with a transmission-beam experimental apparatus. The primary anionic beam projectile is produced in a hollow cathode discharge-induced plasma, and the collisions with the neutral molecular target occur in a gas cell at a well-known constant pressure. The accurate determination of the gas pressure (within 8%) in the scattering chamber allowed us to clarify the important discrepancies (by about a factor 4) prevailing between previous total electron detachment cross-section measurements. Additional local maxima in the cross-section values, not previously observed, have been detected around 50 and 150 eV.
Towards optimizing the non-invasive sensory feedback interfaces in a neural prosthetic control
Authors: Su Shiyong , Chai Guohong , Meng Jianjun , Sheng Xinjun , Mouraux André , Zhu Xiangyang
Published: January 2022

Objective. The somatotopic interface (SI) and non-somatotopic interface (NI) are commonly used to provide non-invasive sensory feedback. Nevertheless, differences between somatotopic and non-somatotopic feedbacks are rarely reported, and objective evaluations of the corresponding brain response are missing as well. Few studies have reported how to design the stimulation encoding strategy based on the two interfaces in sensory feedback. The objective of this study was to investigate the difference in sensory characteristics between SI and NI, and propose an optimal encoding method for non-invasive feedback interfaces. Approach. We recruited seven amputees and compared the tactile sensitivity to stimulated positions and intensities between SI (phantom finger area) and NI (upper arm) in a tactile discrimination task. Electroencephalography (EEG) evaluation task was subsequently conducted to objectively evaluate the stimulus-evoked brain response for SI and NI. Finally, the two kinds of tactile information (stimulated position and intensity) was applied to an object recognition task in a closed-loop prosthesis control system. Specifically, the object size was reflected by the prosthetic finger position through stimulated position encoding, and the object stiffness was reflected by the contact force of prosthetic fingers through stimulated intensity encoding. We compared the performance under four feedback conditions (combinations between two kinds of tactile information and two interfaces). Main results. Behavioral results showed that NI was more sensitive to position information while SI was more sensitive to intensity information. EEG results were consistent with behavioral results, showing a higher sensitivity of sensory alpha ERD and a stronger correlation between alpha ERD and discrimination accuracies for NI in the position discrimination, while the trend was opposite in the intensity discrimination. The feedback encoding allowed amputees to discriminate the size and stiffness of nine objects with the best performance of 62% overall accuracy (84% for size discrimination, 71% for stiffness discrimination) when position and intensity information was delivered on the NI and SI, respectively. Significance. Our results provided an instructive strategy for sensory feedback via non-invasive solutions.
Modeling multiscale causal interactions between spiking and field potential signals during behavior
Authors: Wang Chuanmeizhi , Pesaran Bijan , Shanechi Maryam M
Published: January 2022

Objective. Brain recordings exhibit dynamics at multiple spatiotemporal scales, which are measured with spike trains and larger-scale field potential signals. To study neural processes, it is important to identify and model causal interactions not only at a single scale of activity, but also across multiple scales, i.e. between spike trains and field potential signals. Standard causality measures are not directly applicable here because spike trains are binary-valued but field potentials are continuous-valued. It is thus important to develop computational tools to recover multiscale neural causality during behavior, assess their performance on neural datasets, and study whether modeling multiscale causalities can improve the prediction of neural signals beyond what is possible with single-scale causality. Approach. We design a multiscale model-based Granger-like causality method based on directed information and evaluate its success both in realistic biophysical spike-field simulations and in motor cortical datasets from two non-human primates (NHP) performing a motor behavior. To compute multiscale causality, we learn point-process generalized linear models that predict the spike events at a given time based on the history of both spike trains and field potential signals. We also learn linear Gaussian models that predict the field potential signals at a given time based on their own history as well as either the history of binary spike events or that of latent firing rates. Main results. We find that our method reveals the true multiscale causality network structure in biophysical simulations despite the presence of model mismatch. Further, models with the identified multiscale causalities in the NHP neural datasets lead to better prediction of both spike trains and field potential signals compared to just modeling single-scale causalities. Finally, we find that latent firing rates are better predictors of field potential signals compared with the binary spike events in the NHP datasets. Significance. This multiscale causality method can reveal the directed functional interactions across spatiotemporal scales of brain activity to inform basic science investigations and neurotechnologies.
Post-processing techniques using 3D Slicer for T1-weighted MRI analysis of radiochromic gel dosimeters
Authors: Lee Hannah J. , Dolan James , Pencea Stefan , Ibbott Geoffrey S.
Published: January 2022

Radiochromic FXG gel dosimeters were investigated for end-to-end validation of TG-119 plans delivered in the pre-clinical Elekta 1.5 T-7 MV FFF MR-Linac. Due to the noise levels in the T1-weighted MR images, this preliminary study investigated post-processing techniques available in 3D Slicer and their impact on gamma passing rates. Binomial blur and discrete Gaussian image filters were identified as the most impactful on increasing gamma passing rates for T1-weighted MR images; however, any application of image filters should be implemented with caution on the interpretation of the results.
Flexible radiochromic dosimeters development for complex irradiation beams
Authors: Tran Johanna , Agelou Mathieu , Amiot Marie-Noëlle , Boissonnat Guillaume , Dehe-Pittance Chrystèle , Girard Hugues , Lazaro Delphine , Simic Vesna , Tromson Dominique
Published: January 2022

In vivo dosimetry for patient radioprotection is a real challenge concerning new radiotherapy treatments. In this study we aim to develop a dosimeter based on tissue equivalent material, flexible and adaptable to the patient morphology in order to perform in vivo dosimetry for complex irradiation beams. Here, we report the evaluation in standard beams of highly flexible dosimeter composed of a silicone elastomer and containing leucomalachite green as radiochromic dye and give a first estimation of LMG-micelle hydrogel response. All results are compared to a commercially available PRESAGE® dosimeter.
Adaptive radiotherapy dosimetry in a challenging geometry: A model gas-filled tissue expander in a helical TomoTherapy beam
Authors: Kairn T. , Lathouras M. , Sylvander S. R. , Trapp J.V. , Crowe S.B.
Published: January 2022

Helical TomoTherapy treatment and delivery systems (Accuray Inc, Sunnyvale, USA) allow off-line adaptation of radiotherapy treatments, with dose calculations that use MV computed tomography (CT) data acquired at treatment. This study aimed to assess the potential dosimetric effects of a gas-filled temporary tissue expander (TTE) on the accuracy of breast radiotherapy dose calculations from both the TomoTherapy treatment planning system (TPS), which uses kV CT data, and the TomoTherapy adaptive radiotherapy (ART) system, which uses MV CT data. A TomoTherapy treatment plan was created and delivered to a 3D-printed rectilinear model of a breast with implanted gas-filled TTE, including a stainless steel CO2 container, and film measurements of the delivered dose were compared against dose calculations from the TPS and ART systems. The film measurements showed that the TomoTherapy TPS provided comparatively accurate dose calculations in the ~550 cm2 volume of air that modelled the gas filling of the TTE and within the surrounding tissue-equivalent materials, except in regions where the beam was transmitted through the stainless steel CO2 container, possibly due to the volume of stainless steel being over-estimated in the kV CT images that were used to generate the treatment plan. The ART system provided more accurate dose calculations than the TPS in regions affected by the stainless steel container, but also over-estimated the dose in the air within the TTE. These results suggest that the TomoTherapy TPS and ART systems could be used to produce reliable dose calculations of breast treatments in the presence of gas-filled TTEs, if kV CT imaging options are chosen to avoid artefacts and minimise the need for density over-rides and if treatment targets that include only clinically relevant tissues, and exclude all TTE components, are used to evaluate and compare the doses calculated by both systems.
Investigation of target dose conformity using normoxic polymer gel dosimetry techniques: A clinical example of 12th thoracic vertebrae SBRT treatment with VMAT
Authors: Venning A , Mundayadan Chandroth M , Morgan C , Roberts M
Published: January 2022

This paper describes the 3D dosimetry verification of a 24Gy in 3 fractions VMAT SBRT treatment delivery to the 12th thoracic vertebrae (T12). With this fractionation regime, the critical isodose value is 17.5Gy to the outer edge of the spinal cord and must not be exceeded. This is a high-risk treatment that could result in severe injury to the patient unless administered precisely. With the use of 3D normoxic polymer gel dosimetry techniques, using MRI readout, a clinical example is presented which shows that the Mid North Coast Cancer Institute’s paraspinal program is capable of delivering complex distributions with high doses to within very tight tolerances. This also demonstrates the strength of normoxic polymer gel as a 3D dosimeter.
RSC: Gel dosimetry as a tool for clinical implementation of image-guided radiotherapy
Authors: Elter A , Dorsch S , Marot M , Gillmann C , Johnen W , Runz A , Spindeldreier C K , Klüter S , Karger C P , Mann P
Published: January 2022

The implementation of new image-guided radiotherapy (IGRT) treatment techniques requires the development of new quality assurance (QA) methods including geometric and dosimetric validation of the applied dose in 3D. Polymer gels (PG) provide a promising tool to perform such tests. However, to be used in a large variety of clinical applications, the PG must be flexibly applicable. In this work, we present a variety of phantoms used in clinical routine to perform both hardware and workflow tests in IGRT. This includes the validation of isocenter accuracy in magnetic resonance (MR)-guided RT (MRgRT) and end-to-end tests of online adaptive treatment techniques for inter- and intra-fraction motion management in IGRT. The phantoms are equipped with one or more PG containers of different materials including 3D printed containers to allow for 3D dosimetry in arbitrarily shaped structures. The proposed measurement techniques and phantoms provide a flexible application and show a clear benefit of PG for 3D dosimetry in combination with end-to-end tests in many clinical QA applications.
End-to-End Quality Assurance of Stereotactic Radiation Therapy Using an Anthropomorphic Head Phantom
Authors: Alexander KM , Dekker KH , Olding T , Schreiner LJ
Published: January 2022

In the clinic, routine quality assurance tests ensure the proper functioning of each individual aspect of a radiation therapy treatment delivery. However, these tests may not guarantee an accurate treatment delivery. In this work, we present the design and application of a head phantom (using 3D printing technology) developed for end-to-end quality assurance of a stereotactic radiation therapy treatment for brain metastases, coupled with inserts for ion chamber, and film and gel dosimeters. The head phantom was subjected to the entire clinical workflow, with each stage of the process being performed by the appropriate clinical personnel to ensure that this quality assurance test mimics the clinical scenario.
New directions for tetrazolium - gellan gum gel dosimeters
Authors: Penev Kalin I. , Mequanint Kibret
Published: January 2022

Tetrazolium salt-based dosimeters are non-diffusing, gel dosimeters with excellent physical and chemical stability but with relatively low dose sensitivity and a dose rate dependence of the dose response. Both issues are tackled in this study by: (a) the introduction of a new tetrazolium salt with simple synthesis and dose response around 585 nm which may provide the pathway to more sensitive formulations and (b) producing gels with low gellan gum concentration, thus limiting the dose rate effects, and addition of thickening agents to restrain the liquid loss (syneresis) from the resulting gels.
Effect of 60% thickness reduction of Sn-Cu solder alloy on localized micromechanical properties via nanoindentation approach
Authors: Mohd Yusoff F. A. , Bakar Maria Abu , Jalar Azman
Published: January 2022

The relationship between a process and mechanical properties are important in understanding the behaviour of a material under certain conditions. This indicate that mechanical properties of the materials can be modified through certain processing. Hence, this paper investigates the effect of 60% thickness reduction of Sn-Cu alloy in thermomechanical treatment on the localized micromechanical properties. A bar-shape of Sn-Cu solder alloy is subjected to heat treatment at 30°C, 60°C, 90°C, 120°C and 150°C for 20 minutes, followed by 60% thickness reduction via compression process. Sample without compression process was used as control sample. Nanoindentation approach was used to characterize the localized micromechanical properties of the samples. The results show the hardness value for control samples reduced approximately 56%, from 181 MPa at 30°C to 79 MPa at 150°C. Reduced modulus of control sample has shown similar decreasing trend from 149 GPa at 30°C to 85 GPa at 150°C, approximately 43% changes. Lower changes in hardness and reduced modulus observed for thermomechanical treated sample approximately 20% and 18%, respectively. These findings show that thermomechanical treatment has given significant effect on the localized micromechanical properties of Sn-Cu solder alloy.
The Effects of Acidic Secondary Dopants to the Electrical Conductivity of PEDOT: PSS Fabrics
Authors: Ruzaidi Dania Adila Ahmad , Suhaimi Fifi Alfiani , Saripudin Muhammad Adam , Ramli Rosmamuhamadani , Osman Hazwanee , Nadzri Nur Izzati Muhammad , Mahat Mohd Muzamir
Published: January 2022

Conductive polymers commonly used as fillers to enhance electrical properties of composite’s system. However, the low conductivity performance of conducting polymers, namely poly(3,4-ethylenedioxythiophene): poly (4-styrene sulfonate) (PEDOT: PSS), constrains their utilization in the field of conductive textile technology in inventing an advanced textiles’ fabric. Maintaining the stability of impregnated PEDOT: PSS fabrics at the microscopic level remains doubtful and unclear. Nowadays, researchers are actively pursuing the introduction of secondary dopants into PEDOT: PSS dispersion to overcome this challenge. In this study, a conductive PEDOT: PSS fabric via immersion technique was prepared and its effects on conductivity upon doped-secondarily by two different dopants; hydrochloric (HCl) and p-toluenesulfonic (p-TSA) acids was revealed. The volume percentage (vol.%) of the secondary dopants (1, 3, 5, 7, 9 vol.%) were varied to find the optimal vol.% for getting the great value of conductivity of the doped PEDOT: PSS fabrics. These fabrics were then analyzed by using Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR), Electrochemical Impedance Spectroscopy (EIS), and Scanning Electron Microscopy (SEM) to investigate their conductivity performances chemically. It is found that the conductivity values were affected by varying the strength of the acids. It is concluded, that the 7 vol.% and 5 vol.% of HCl and p-TSA, respectively, gave the highest electrical conductivity values of the PEDOT: PSS fabrics. These findings can be used to provide direction and guidance to researchers in advancing the fields of textiles, electronics and advanced materials.
The Application of Natural Dye on Tinted Vehicle Films – A Review
Authors: Idris Siti Nursyakirah , Othman Siti Amira
Published: January 2022

The study present the utilization of natural dye from onion skin on tinted film. Tinted film for the car and helmet visor is produced from Polyethylene Terephthalate (PET) as the main material. However, tinted films that do not meet the Visible Light Transmission (VLT) values authorized for automobiles are being used by some people. Tinted films are also often manufactured using synthetic dyes, which have negative environmental impacts. Thus, the objective of this study was to prepare the tinted film for car and helmet visors that can comply with safety standards (MS1). Tinted film produced must comply with the percentage of VLT allowed which is 30%, 50% and 70%. Synthetic dyes, which are frequently used in the plastic manufacturing sector, will be substituted with natural colours in this study. PET is excellent for manufacturing plastic films because it has a number of benefits, including the ability to act as an amorphouse and semi-crystalline material. Natural dye extracted from onion skin is a good dye because there are Auxochrome groups. By choosing natural dyes over other options, we are helping to protect the environment and reducing human reliance on toxic chemicals.
Thermal cycling effect on the crack formation of solder joint in ball grid array package
Authors: Suhaimi M. F. , Abu Bakar M. , Jalar A. , Che Ani F. , Ramli M. R.
Published: January 2022

Ball grid array (BGA) technology is one of the technologies used in surface mount technology (SMT). It provides many interconnection points via the solder ball and thus give advantages such as good heat dissipation, improved the PCB design, BGA package become robust and reliable. In electronic industry, the reliability of BGA package is being concerned. Thermal cycling test (TCT)is one of typical reliability test used to investigate the reliability of the BGA package. This study investigates on the thermal cycling effect on the crack formation of solder joint in ball grid array package. The BGA package was subjected to thermal cycle test with temperature cyclic of -40°C and 85°C for 500, 750 and 1000 cycles. The finding shows that the cracks were observed in solder joint in 750 and 1000 cycles. This shows that the BGA package is sensitive to the thermal cycling and effect its reliability. The package was modified with adding underfill materials and tested through the same cycles. Cross sectional and Dye and pry test show no crack formation and dye penetration for all thermal cycles in the BGA package with underfill.
Microstructure Study of Mix Assembly Lead-free Sn-Ag-Cu Ball Grid Array and Sn-10Cu Solder Paste
Authors: Said Rita Mohd , Sulwarajan Kalaiarasi A/P , Razak Nurul Razliana Abdul , Somidin Flora , Zaimi Nur Syahirah Muhammad
Published: January 2022

In recent years, electronic technologies have been striving to minimize the use of lead in their manufacturing and production. As a result, the electronic packaging industry is slowly transitioning from lead solder to lead-free solder. Though environmentally lead-free solders are advantageous, there are still needs some work in meeting current technological demand and requirements. In this study, the microstructure analysis on lead-free Sn-Ag-Cu Ball Grid Array (BGA) and Sn10Cu solder paste was done. The main aim of this study is to investigate the effect of isothermal aging on the microstructure of the solder paste joint and evaluate the intermetallic compound (IMC) thickness on the solder joint reliability. Optical Microscope (OM) and ImageJ software have been utilized to study the bulk solder microstructure. The results show that the bulk microstructure consists of β-Sn and Cu6Sn5 / β-Sn eutectic phases. The IMC layer has undergone rapid growth with increasing aging temperature and time. The two main IMC layers (Cu3Sn and Cu6Sn5) grew thicker due to high temperature. The growth kinetic of Sn10Cu resulted in 16.70 kJ/mol activation level. Therefore, the significance of the findings from this study might provide a potential answer for future development for highly reliable solder joint applications.
The Influence of Indium, In on Microstructure Evolution During Isothermal Aging of Sn-0.7Cu
Authors: Ghazali Saidah Najihah Mohd , Sharif Nurulakmal Mohd
Published: January 2022

This paper reports influence of isothermal aging on bulk solder and the microstructure evolution of commercial Sn-0.7Cu (Sn-0.7Cu-0.05Ni+Ge) Pb-free solder alloy with addition of bismuth (Bi) and indium (In). Sn-0.7Cu, Sn-0.7Cu-1.0Bi, Sn-0.7Cu-1.0Bi-1.0In, Sn-0.7Cu-1.0Bi-4.0In, Sn-0.7Cu-1.0Bi-7.0 In solder alloys were prepared via casting process. The solder alloys were aged isothermally at 180°C for 500 hours and microstructure was compared with that of as-cast solder. Microstructure of bulk solder and melting temperatures were analysed via scanning electron microscopy, SEM and differential scanning calorimetry, DSC. The addition of In up to 7 wt% reduced the melting temperature from 231.1 to 218.5°C, and crystallisation temperature from 205.8 to 194.7°C with decreasing degree of undercooling which indicates that the In-added solder alloy had faster nucleation rate. Microstructure evaluation showed that as the amount of indium added increased to 7.0 wt%, the ß-Sn grains became smaller suggesting a refinement effect with In addition. Indium addition also encouraged the formation of Sn-In and Bi-In IMC which increased as the amount of In increased. These IMCs could potentially act as blocking mechanism for deformation leading to higher strength.
Influence of Copper Substrate Roughness on the Growth of Intermetallic Compounds Layer in SAC305 Solder Joints
Authors: Atiqah A. , Rahim R.A.A.A. , Jalar A. , Siow K. S.
Published: January 2022

This study aimed to evaluate the effect of surface morphology of copper (Cu) substrate on the intermetallic compound (IMC) growth and interfacial reactions when soldered with SAC305 lead-free solder during a thermal aging process. The surface morphology conditions of the Cu substrate influence the growth activity of the IMC layer. This study used different grits of silicon carbide (SiC) abrasive paper (400, 800 and 1200) to grind the Cu substrate to produce different surface roughness. The resulting Cu surface morphologies were examined using an infinite focus microscope (IFM), and the parameters used in this stereometric analysis were profile roughness. Hand soldering was used to melt the SAC305 solder on the Cu substrates with different surface roughness. Subsequently, the samples were subjected to an aging temperature of 150 °C for 800 hours to grow the IMC layers. Thermal aging increased the IMC thickness at the Cu-SAC305 interfaces. After thermal aging, the IMC layer thickness and related parameters were measured and analyzed with the IFM. The growth of the IMC layer thickness depended on the different surface morphology of the substrate when the aging temperatures and Cu materials were maintained in this study. In general, the IMC morphology for the rougher Cu substrate had a scallop-shaped and uniformed layer compared to those IMC from the smooth Cu substrate. The Cu substrate ground surface roughness with 400 grit SiC abrasive paper produced an average roughness, Ra
of 505.02 nm; this roughness produced the thinnest IMC layers compared to the different Cu substrates ground by SiC abrasive paper of different grits.
Preliminary investigation on the correlation between mechanical properties and conductivity of low-density polyethylene/carbon black (LDPE/CB) conductive polymer composite (CPC)
Authors: Badrul Farah , Abdul Halim Khairul Anwar , Mohd Salleh Mohd Arif Anuar , Omar Mohd Firdaus , Zakaria Azlin Fazlina , Muhamad Nor Asiah , Zakaria Muhammad Salihin
Published: January 2022

The insulating nature of a polymer can be changed to electrically conductive by incorporating conductive fillers within the polymer matrix to form a conductive polymer composite (CPC). One of the potential application of CPCs are in the area of flexible electronic interconnect application. Nevertheless, the correlation between the electrical conductivity and mechanical properties of CPCs such as tensile was found to be limited. Therefore, this paper is aimed to report the preliminary investigation on the correlation between conductivity and mechanical properties of a low-density polyethylene (LDPE) incorporation with conductive filler which is carbon black (CB. It was observed that the tensile strength was decreased by up to 29.4% and the elongation of break was decreased by up to 90.6% at higher CB loading compared to pure LDPE. Nonetheless, the modulus of elasticity and the electrical conductivity of the composites were increased by up to 150.5% and 16.4% at higher CB loading respectively. Moreover, it was found that the effect of CB additions on the tensile modulus was greater compared to the conductivity of the CPCs.
Comparison on oil and water absorption ability of various natural fiber
Authors: Mohamad Rosdi Mohamad Hilmi Hisyamuddin , Ahad Nor Azwin , Shahdan Dalila
Published: January 2022

The natural fibers from trees, agricultural waste, fruit skins and others will be considered as recyclable and recently have been used widely as filler materials in polymer composites. As an alternative, natural fibers have become the attention of researchers to substituate the commercial, synthetic and costly fibers. Therefore, this study has used 6 types of natural fibers from local fruit waste in Malaysia, and investigate the ability of each of them to absorb oil and water. All natural fiber showed different absorption percentage within the testing period. The natural fiber which more hydrophilic goes to coconut shell, againts peanuts as the lowest in absorbing water. Meanwhile, coconut residue capable to absorb more oil than coconut shell which showed oleophobic behaviour. The cellulose content, the hollow or pores and also the types of natural fiber are the factors that affect the percentage of oil and water uptake.
The preparation of an insulator material using renewable sources and application of palm oil tree – A Review
Authors: Elias Nur Amirah , Othman Siti Amira
Published: January 2022

Excessive heat will cause discomfort while doing daily life even the use of electrical items such as fans and air conditioner are not entirely helpful. This is because the building does not have a layer to absorb the heat. Then, the best initiative to lessen the heat in building is by adding thermal insulation material into the building material. Past researcher shown most thermal insulators used are fiberglass, mineral wool, polystyrene and polyurethane foam. However, there are some flaws with the thermal insulator that cause new ideas to emerge namely cellulose. Cellulose is an insoluble substance that is a major component of plant cell walls and vegetable fibres such as cotton. Normally cellulose can be found in the plants. By cause to the increasing surplus of oil palm trees then the use of cellulose in oil palm is the best. This paper review discusses about preparation of an insulator material using renewable sources and application of palm oil tree.
Microstructural Evolution of Cu/Sn-58Bi/Sn-3.0Ag-0.5Cu Composite Solder Joint during Isothermal Aging
Authors: Somidin Flora , Abu Bakar Muhammad Fakarudin , Abdul Razak Nurul Razliana
Published: January 2022

A composite solder joints made of Cu/Sn-58Bi/Sn-3.0Ag-0.5Cu (in weight percent) was successfully fabricated. The composite solder was made from combining a Sn-3.0Ag-0.5Cu solder ball and Sn-58Bi solder paste. The composite solder was reflowed on Cu-OSP (copper-organic solderability preservatives) substrate to form a composite solder joint. The microstructure evolution of the composite solder joints under different reflow temperature and thermal aging conditions were investigated using an optical microscope. This study shows that a composite solder joint of SAC305/Sn-58Bi can be assembled at lower temperature (160 °C) and gradually mixed through isothermal aging.
Mechanical properties and deformation modes of grade 1 commercially pure titanium at cryogenic temperature
Authors: Lee Min-Su , Jun Tea-Sung
Published: January 2022

In this study, we have investigated the deformation behaviour of Grade 1 commercially pure titanium at 20°C, -100°C and -170°C. Optical microscope and electron backscatter diffraction were applied to characterise the twins activated during tensile testing and the crystal orientations of the sample, and further to analyse the orientation dependent slip activity. The higher density of twins was exhibited at lower deformation temperature. The twinning activity was also higher in the parallel loading (RD) than transverse loading (TD) to rolling direction. According to the Schmid factor analysis, the grains were most favourable for -prism slip in the RD sample, whilst the large fraction of grains was favourable for -basal slip in the TD samples. The activation of slip systems is anticipated to be changed with decreasing temperature due to the different effect of temperature on critical resolved shear stress between slip systems. The work-hardening was affected by twinning- and dislocation-induced hardening depending on the temperature and crystal texture. Consequently, the high work-hardening capacity increased or maintained the total elongation (EL) with decreasing temperature (EL: 66% vs. 70% (RD) and 55% vs. 51% (TD) between 20°C and -170°C).
Effect of the nickel coated precipitated calcium carbonate addition on microstructure, phase and wettability of Sn-9Zn solder
Authors: Leong Wai Keong , Mohamad Ahmad Azmin , Mohd Nazeri Muhammad Firdaus
Published: January 2022

This paper presents the effect of nickel-coated precipitated calcium carbonate (Ni-coated PCC) on the wettability, microstructure and phase change of Sn-9Zn solder. The microstructure and phase analysis of the material plays a very important role as it determines the physical and mechanical behavior of materials. Both Sn-9Zn and Ni-coated PCC/Sn-9Zn produced almost similar microstructure, which contain needle-like, dark phase Zn-rich phase and distributed evenly in beta-Sn rich matrix. However, compared to pure Sn-9Zn, the addition of Ni-coated PCC produce finer size of Zn rich phase needle-like structure. The presence of new phases of nickel tin and calcium carbonate compounds was also found with the addition of Ni-coated PCC. This believed to help in refining the size of Zn-rich needle structure, while retaining the original phases of Sn and Zn of the Sn-9Zn solder, Furthermore, Ni-coated PCC/Sn-9Zn have a smaller contact angle compared to pure Sn-9Zn. This can be explained that, Ni-coated PCC reinforced particle was the interfacial active element and decrease the interfacial energy between the solid and liquid. The microstructure and phase analysis of the material plays a very important role as it determines the wettability behavior of the material
Sample Preparation of the Natural Source Hydroxyapatite (HAp) derived from Black Tilapia Fish Scales
Authors: Jaffri Muhamad Zaki , Mohd Ismail Zamratul Maisarah , Dermawan Siti Khadijah , Abdullah Hasan Zuhudi
Published: January 2022

Hydroxyapatite (HAp) is a biomaterial with the chemical formula Ca10(PO4)6(OH)2. Normally, it was used and applied in biomedical applications, cooking recipes and healthy food products. Due to this, it has attracted the researcher to work on HAp synthesis and extraction. In this study, the hydroxyapatite was extracted from fresh water Black Tilapia Fish Scales (BTFS) was analysed. The crystallinity of the HAp was characterized by using an X-ray diffractometer (XRD) whereas the Fourier transform infrared (FTIR) analysis was used to characterize the presence of HAp from the samples. Scanning electron microscopy (SEM) provided with an Energy Dispersive Spectroscopy, (EDS) was used to investigate the morphology and element of the hydroxyapatite powders. The BTFS samples were heated at 100 °C to composed and eliminated the remaining meat and other impurities. A mechanical crusher was applied to make a miniscule and fine hydroxyapatite powder using a thermal calcination technique using a furnace. The BTFS samples powder were calcined at a temperature of 900 °C for 3 hours correspondingly. The XRD spectra findings, uncovered the existence of the obtained BTFS HAp are articulate with Joint Committee on Powder Diffraction Powder Standard data (JCPDS) from the library. From the SEM results, HAp powder presence in hexagonal shape. The findings show the potential of producing high-value products from fishing waste, such as HAp with Ca/P ratio 1.74, for biomedical applications.
Effect of stencil wall aperture on solder paste release via stencil printing
Authors: Mohamed Sunar M. S. , Abu Bakar M. , Jalar A. , Che Ani F. , Ramli M. R.
Published: January 2022

Solder paste printing is a process by which the correct amount of solder paste is applied to the printed circuit board via a stencil. The solder release from the stencil printing process very much depends on the type of solder paste and stencil conditions such as the shape of the aperture, size, and thickness of the stencil. This paper investigates the stencil condition in particular the stencil wall aperture and its relationship to the solder release ability. In this work, two types of stencil wall openings A and B were used, which differ in a different ways of cutting to achieve the wall aperture. The cutting process produced different surface roughness of the wall aperture of the stencil. Stencil printing was performed to print the solder paste onto the PCB pad. The release of solder paste was observed by solder paste inspection (SPI) and analyzed qualitatively and quantitatively. The results show that stencil B gives a better solder compared to stencil A. This is due to the smoother wall aperture compared to stencil A which has a roughened wall aperture. This shows that the performance of stencil printing in terms of solder printing quality is highly dependent on the surface roughness of the stencil aperture. Stencil quality is important as it affects the performance of solder paste printing, and this process is mainly carried out in the electronics industry. Therefore, understanding stencil conditions is important for electronic technology that uses solder printing.
End-to-end Saliency Face Detection and Recognition
Authors: Gao Jingqian , Xu Minqiang , Wang Huan , Zhou Ji
Published: January 2022

Face recognition is a long-lasting hot topic in compute vision. The face recognition system mainly includes face detection, alignment and feature extraction. In the forward task, the extracted features are used to measure the similarity between faces, and outputs whether those are same person or not or which person it is in the registered set. Typically, the three stages of recognition system training independently of each other have the following shortcomings: 1) redundant calculation of feature maps; 2) unable to end-to-end optimization; 3) detecting an extracting so much useless face. A lightweight model for saliency face detection and recognition that can be optimized end-to-end is proposed. While maintaining accuracy, it meets the real-time and memory limitation requirements in embedded devices or terminals.
Building and Applying Knowledge Graph in Edge Analytics Environment
Authors: Zhang Hui , Niu Yingtao , Ding Kun , Kou Shaoqin , Liu Liu
Published: January 2022

For the scenario of limited hardware resources and restricted software environment in edge computing architecture, the method of building and applying knowledge graph in edge analytics environment is proposed. The main process includes: building knowledge graph in the cloud, storing knowledge base with RDF format at the edge through customization and transformation, and performing query and analytics at the edge with SPARQL graph search language. The method is simulated in a communication anti-jamming test environment, and the results show that the relevant technical solutions can better meet the requirements of construction of knowledge graph and data analysis in a restricted edge analytics environment.
Research on the Application and Analysis of Mechanical Equipment Intelligence Based on Knowledge Graph
Authors: Qi Rui , Chen Jing , Yu ZengWen , Ke WenJun , Wang Rui
Published: January 2022

With the rapid evolution of manufacturing technology, mechanical equipment products are being replaced more frequently, and competition in the industry is becoming increasingly fierce. The collection and analysis of mechanical equipment technical intelligence is a key need for many enterprises. Using artificial intelligence technology to build an intelligence analysis system for all types of data is the inevitable trend of intelligence analysis. This paper proposes an intelligent processing and analysis framework of mechanical equipment intelligence. Based on the construction of knowledge graph, the knowledge embedding model is used to complete knowledge reasoning, predict development trends for mechanical equipment, and allow for more intelligent decision-making. A case study involving 3D printing shows the functions of the intelligence process and analysis framework.
Spatio-Temporal Transformer for Online Video Understanding
Authors: Du Zexu , Zhang Guoliang , Lu Weijiang , Zhao Ting , Wu Peng
Published: January 2022

Leading methods in the field of online video understanding try to extract useful information from the spatial and temporal dimensions of an input video. But they are suffering from two problems: (1) These methods can only extract local video information, and cannot relate to the important features of the temporal context in the video. (2) Although some methods can quickly process the information of each frame in the video, the processing efficiency of the whole video is not good, so this type of method cannot be applied to online video understanding tasks. This article introduces a Transformer-based network, which considers spatial and temporal content, and can quickly process each video at the same time. Our approach can efficiently handle up to 170 videos with hundreds of frames per second for action classification. Our method achieve 10 to 90 times faster than existing methods on the action classification datasets.
Multi-contrast MRI Reconstruction via Multi-scale Patched-based Cross-contrast Channel Selection
Authors: Yang Zehua , Liu Chengliang , Xu Yong
Published: January 2022

In this paper, we tackle the under-sampled MRI reconstruction problem with auxiliary contrasts. Instead of adopting a naive fusion scheme before feeding the multi-contrast features into the networks, we propose a more interpretable early fusion approach. By utilizing the inherent multi-contrast nature of MR image feature maps, we propose a Cross-contrast CHannel Selection (CCHS) module to explicitly explore dependency between channels for better cross-contrast fusion in reconstruction of the target one. Furthermore, the CCHS module is extended into a more adaptive version by introducing a multi-scale patch-based learning strategy. Quantitative and qualitative experimental results on the fastMRI dataset demonstrate the effectiveness of our approach.
Load Clustering Method Based on Improved Density Peak and Gaussian Mixture Model
Authors: Zhe Dong , Ya Wang , Chuanxiao Ma , Weihan Ai
Published: January 2022

A load clustering method based on improved density peak and Gaussian mixture was proposed to solve the problems that standard Gaussian mixture clustering algorithm (GMM) with random initial clustering center was easy to fall into local optimum in the clustering analysis of residential electricity behavior, and the density peak algorithm (DPC) needed to manually select the clustering center.The method combines the Cosine distance and Euclidean distance, which reflect the similarity of curve shape, and selects the clustering center automatically through the sine value relation of relative Angle between two points in γ descending graph. The clustering center selected by the improved DPC algorithm was used to initialize the parameters of the GMM model. Finally, load clustering is carried out by GMM model. The results of calculation examples show that the proposed method can effectively improve the efficiency of daily load curve clustering.
Polyphyletic Loss: Litchi Flower Detection with Occlusion
Authors: Ye Jin , Wu Menglan , Qiu Wenjie , Yang Juan , Lan Wei
Published: January 2022

Controlling shoot and promoting flower of litchi is one of the key technologies for the high yield of fruit trees, but the occlusion caused by dense growth has a great impact on the detection of flowers. To solve the problem, this paper designs a polyphyletic loss function to detect the occlusive litchi flowers. A new aggregation loss term is proposed in the loss function to force the proposal box to approach and compactly locate the corresponding target. At the same time, the segmentation loss of the bounding box specially designed for the dense crop scene is added to keep the prediction box away from the surrounding objects and improve the robustness of detecting a large number of flowers. We conducted experiments on the self-built litchi flower data set and the multi species fruit flower data set at the same time. Compared with other methods, the proposed method has higher robustness and detection accuracy, which provides an important idea and method for flower number statistics and fruit yield prediction in dense scenes.
Performance Analysis of SWIPT System with Imperfect Channel State Information
Authors: Zhang Chenxi , Meng Chao , Yang Yu , Gao Yan
Published: January 2022

This paper studies the system performance of the multiple-input-single-output (MISO) system using simultaneous wireless information and power transfer (SWIPT) technology under imperfect channel state information. A power split strategy is used in the receiver, which divides the received radio frequency (RF) signal into two parts, one part is directly used for signal decoding, and the other part is used as energy harvesting. This paper studies the optimization of system channel capacity under the constraints of harvested energy and the transmission rate. The resulting optimization problem is a two-layer non-convex optimization one, which is simplified by Cauchy-Schwarz inequality. Through the linear search of the energy division ratio in its value range, it becomes a one-dimensional optimization problem only related to the transmission power, which can be solved by CVX. The simulation results verify the effectiveness of the algorithm.
Research on Automatic Driving Target Detection Based on YOLOv5s
Authors: Li Chao , Cao Yining , Peng Yakun
Published: January 2022

Aiming at the problems of low detection accuracy, small targets and inaccurate recognition of automatic driving in natural scenes such as different lighting, different weather and different perspectives. The yolov5s network, migration learning method and varifocal loss function are used, and the hyper-parameter adjustment and network fine-tuning are completed. Experimental results show that the proposed method achieves mean Average Precision of 46.68%, and the detection speed can reach 7ms/frame. Automatic driving target detection based on YOLOv5s model network has fast training results, easy deployment, strong robustness, and high recognition accuracy in different weather conditions. It can not only meet the accuracy of automatic driving target detection, but also meet the real-time detection.
Implementation and Error Analysis of MNIST Handwritten Dataset Classification Based on Bayesian Decision Classifier
Authors: Ma Rui , Han Long , Geng Hujun
Published: January 2022

In recent years, with the continuous development of computer technology, pattern recognition technology has gradually entered people’s life and learning, and people’s demand for pattern recognition technology is also growing.In order to adapt to people’s life and study, the application of pattern recognition theory is more and more, such as speech recognition, character recognition, face recognition and so on.The main methods of pattern recognition are statistics, clustering,neural network and artificial intelligence.Statistical method is one of the most classic methods, and Bayesian classification is widely used in statistical method because of its convenience and good classification effect.
Intrusion Detection Model Based on Autoencoder and XGBoost
Authors: Kang Yunxiang , Tan Minsheng , Lin Ding , Zhao Zhiguo
Published: January 2022

In recent years, machine learning algorithms have been extensive used for intrusion detection field. At the same time, these algorithms still suffered from low accuracy due to data imbalance. To improve accuracy of detection, an intrusion detection model based on Autoencoder (AE) and XGBoost (IDAE-XG) is proposed. The training algorithm and detection algorithm related to IDAE-XG are given. IDAE-XG constructs the training set with preprocessed normal data. Data preprocessing includes feature selection and feature grouping. Through detection, XGBoost is used to predict results, which effectively improves prediction accuracy. The superiority of the proposed IDAE-XG is empirically demonstrated with extensive experiments conducted upon CSE-CIC-IDS2018. The experimental comparison show that IDAE-XG performs better than the KitNet model in the test, and has achieved a great improvement in accuracy and recall rate.
Hybrid Pruning Method Based on Convolutional Neural Network Sensitivity and Statistical Threshold
Authors: Guo Changyi , Li Ping
Published: January 2022

The hybrid pruning algorithm can not only ensure the precision of the network, but also achieve a good balance between pruning ratio and computation. However, traditional pruning algorithms use coarse-grained or fine-grained pruning networks, which have the tradeoff problem between pruning rate and computation amount. To this end, this paper presents. A hybrid pruning method of sensitivity and statistical threshold. Firstly, coarse-grained pruning is carried out on the network, and a fast sensitivity test is conducted on the convolutional layer of the network to determine the channels that need pruning within the tolerance range of network precision decline. Then, fine-grained pruning is performed on the network. Count the weights of the pruned network, calculate the thresholds of the weights of each layer, and delete the weights less than the thresholds so as to further reduce the size of the network and the amount of calculation. Hybrid pruning performs very well in AlexNet and Resnet networks. In particular, the method proposed in this paper is used in CIFAR-10 dataset, and the compression of FLOPs is 60%, while the compression of parameter number is nearly 80%. Compared with single pruning method, Hybrid pruning is better.