bluuebunny/crossref_metadata_2025 huggingface dataset:
Vulnerabilität von COPD-Patienten für Hitzestress und Luftbelastung
Authors: Hoffmann Christina
Published: February 2020

Eine zunehmende Zahl von Forschungsarbeiten lieferten Indizien dafür, dass Temperaturextreme und Luftverschmutzung das Exazerbationsrisiko von COPD-Patienten erhöhen können.

Im Zusammenhang mit der Gesundheit von COPD-Patienten wurden am häufigsten die Auswirkungen von Feinstaub, Stickstoffoxiden und Ozon, seltener von Kohlenstoffmonoxid oder Schwefeldioxid untersucht. Die beobachteten Assoziationen umfassen verstärkte respiratorische Symptome, Verlust der Lungenfunktion und eine Zunahme von Krankenhausaufnahmen. Schadstoffe in der Luft könnten über folgende Pathomechanismen eine Exazerbation auslösen: Reizung der Lungen, Auslösen einer Entzündungsreaktion, Begünstigung von Infektionen und Reduktion der Ziliarfunktion.

Anstiege akuter COPD-Exazerbationen werden sowohl bei kalten Temperaturen im Winter als auch während Hitzewellen im Sommer beobachtet. Die Charakteristika der vulnerablen Patienten unterscheiden sich zwischen den Jahreszeiten. Bei Kälte zeigen ältere COPD-Patienten erhöhte Exazerbationsraten. In heißen Sommern sind Patienten mit kardialer Komorbidität betroffen, sowie Raucher.

Wenn wir die Vulnerabilität der Patienten verstehen lernen, kann uns das dabei helfen, Adaptationsstrategien zu entwickeln und Exazerbationen vorzubeugen.
Aufruf zeigt Risiken auf
Authors: Mareike Bauner
Published: February 2020

Wendy L. Applequist und ihre Co-Autoren beschreiben in ihrem Aufruf „Scientists' Warning on Climate Change and Medicinal Plants” die schädlichen Auswirkungen des Klimawandels auf die Heilpflanzen. Der Appell wurde kürzlich in Planta Medica veröffentlicht und von vielen Wissenschaftlern unterzeichnet.
Interprofessionelle Kooperation in klinischen Studien
Authors: Zippel Claus , Giesel Frederik L. , Kopka Klaus
Published: February 2020

Um neue Erkenntnisse in für Patienten nützliche Behandlungsansätze überführen zu können, werden in der medizinischen (onkologischen) Translationsforschung zunehmend prospektive klinische Studien initiiert. Damit diese Studien möglichst effizient und effektiv durchgeführt werden können, bedarf es der engen Kooperation und Kommunikation von Experten aus verschiedenen Berufsgruppen. In diesem Aufsatz beleuchten wir am Beispiel der prospektiven onkologisch-klinischen DKTK-PSMA-Studie der Phasen-I/-II „68Ga-PSMA-11 in Hochrisiko-Prostatakrebs“, welche wesentlichen Professionen bei der Planung, Vorbereitung und Durchführung von (nuklearmedizinisch) klinischen Studien involviert sein können und welche essenziellen Aufgaben diese zur Verwirklichung der Studie leisten. Darauf aufbauend führen wir allgemeine organisatorische Maßnahmen an, durch welche die interprofessionelle Zusammenarbeit bei künftig weiteren (nicht nur onkologischen) Studien gefördert werden kann.
Recurrent Infections in a Patient with Multiple Myeloma
Authors: Kini Sanjay , Shanbhag Aravind , Chandramohan Sachin
Published: February 2020

An 80-year-old woman with recurrent urinary tract infection presented to the orthopaedic OPD at KS Hegde Memorial Health Center, Bailur, with gradual onset of generalized weakness, fatigue, anorexia, musculoskeletal pain, and particularly severe backache. The patient was diagnosed to have anemia but renal function tests were normal. X-ray spine showed multiple compression fractures. Serum electrophoresis confirmed the diagnosis of multiple myeloma. In an elderly patient with myalgia, anemia, and recurrent infections, the differential diagnosis of multiple myeloma should be kept in mind as it is often missed by clinicians.
Awareness Among Dental Undergraduate Students Regarding CAD/CAM Technology—A Survey Report
Authors: Palanisamy Sushmita V. , Hegde Chethan
Published: February 2020

Background Contemporary dentistry is advancing toward computer-aided design/ computer-aided manufacturing (CAD/CAM) technology. But the budding dentists are unaware about the advancement. This survey aims at detecting the level of awareness among the undergraduate students and then correlating those results to modify the future curriculum.

Objective The study aims (1) to assess the awareness among the dental undergraduate students and (2) to correlate the level of awareness among the third years, final years, and interns.

Sample Selection Study sample consist of 300 students (third year students, final year students, and interns) of A. B. Shetty Memorial Institute of Dental Sciences, Mangalore, Karnataka, India. The information of the survey was collected with the help of a questionnaire.

Results More than 70% of the students were aware about the basic functioning of CAD/CAM unit and approximately 74% of the students were unaware about the materials used to fabricate the prosthesis using CAD/CAM technology.
Hearing Aid Reimbursement: A Discussion of Influencing Factors
Authors: Fifer Robert C.
Published: February 2020

Reimbursement for hearing aids in the present time has become as complicated, if not more so, than any other area of health care. For many years, hearing aids were a noncovered item where insurance was concerned. The predominant model of bundling costs into a single dollar amount was copied decades ago from hearing instrument specialists. However, insurance companies and federal agencies are increasingly covering the cost of the diagnostic hearing evaluation and at least some of the costs associated with hearing aid purchases. One operational question is whether the bundled charge model is still appropriate, or should audiologists follow more closely the example of optometry whereby professional services are charged separately from the cost of goods sold? The models that have evolved constitute a broad mixture of bundling, partial bundling (i.e., partial unbundling), and complete unbundling. There exists no uniformity for which charge method is best. But, with greater frequency, insurance requirements are forcing a movement toward partial or complete unbundling of associated costs. Regardless of which charge model is adopted, calculation of the cost of service delivery for each audiology practice is an essential business component to justify charges and make educated decisions regarding participation in various insurance, cooperative, or network plans.
The Hearing Health Care Journey: Putting Beans in Your Cups
Authors: Harvey Michael A.
Published: February 2020

One of the areas MarkeTrak has explored is the customer journey through hearing health care. The survey has asked question regarding how long they had a hearing loss before they took some type of action, where did they start their journey, why did they obtain hearing instruments or not, and what the hearing instruments cost. To put that journey in perspective, this article looks at the journey of one specific individual and explores their attitudes about their hearing loss through the eyes of a psychologist.
Fighting climate change as a global equity investor
Authors: Mercereau Benoît , Neveux Guillaume , Sertã João Paulo C. C. , Marechal Benoît , Tonolo Gianluca
Published: February 2020

How could global equity investors fight climate change and what are the implications for their portfolios? We construct a new climate alignment database to address these questions. Investors can fight climate change in two ways: by funding firms aligned with a sub 2 °C scenario; and by engaging firms to lower their climate footprint. Investing in climate-aligned firms does not raise portfolio risk much. For example, a simple 1.5 °C equity portfolio is only 0.9 pp more volatile than global equities. The reason is simple: most sectors have climate-aligned firms. Hence, “low-temperature” portfolios can diversify across sectors. Engagement has huge potential. All firms adopting their sector’s existing best practices may bring the world economy back on a 2 °C trajectory. Moreover, engagement does increase portfolio risk, and may even boost returns. Overall, investors can fight climate change without foregoing returns or increasing portfolio risk substantially.
Probing the surface oxidation process in hexagonal boron nitride epilayers
Authors: Wang Q. W. , Li J. , Lin J. Y. , Jiang H. X.
Published: February 2020

Thermal neutron detectors based on hexagonal boron nitride (h-BN) epilayers have demonstrated a record high efficiency among solid-state detectors at 58%. It was found that the performance of h-BN detectors is profoundly influenced by charge recombination at the surfaces. The dynamic process of surface oxidation in h-BN epilayers has been probed by x-ray photoelectron spectroscopy. The spectra of high-resolution (0.1 eV) scans indicated that the linewidth of the B 1s peak at 190.6 eV increased and the peak intensity decreased with an increase in exposure time in-air (tair). The main B 1s peak at 190.6 eV evolved into multiple peaks at a higher binding energy position due to oxygen impurities tending to occupy nitrogen sites and form the B–O bond. Time constants of the oxidation process have been determined, revealing that the formation process of the B–O bond is very fast and within minutes in h-BN. The results suggest that reducing nitrogen vacancy generation during growth and employing surface treatment techniques would further improve the performance of h-BN devices.
Genetic differentiation in mountain-dwelling clam shrimp, Paralimnadia (Crustacea : Branchiopoda : Spinicaudata), in eastern Australia
Authors: Schwentner Martin , Giribet Gonzalo , Combosch David J. , Timms Brian V.
Published: February 2020

The majority of Australian Spinicaudata Linder, 1945 inhabit the (semi)arid deserts of Australia’s lowlands. However, several closely related species of Paralimnadia Sars, 1896 inhabit small temporary habitats throughout the Great Dividing Range in eastern Australia. By combining analyses of mitochondrial cytochrome c oxidase subunit I (COI) with double-digest restriction-site associated DNA (ddRAD) data, we studied the species diversity and genetic diversity of this group of mountain-dwelling branchiopods. Levels of genetic differentiation in COI are relatively low between putative species (mostly between 1.5 and 6.7%), complicating COI-based species delimitation. Depending on the applied threshold, three to six species are inferred in the studied area, with most putative species being geographically restricted. Particularly notable are the high levels of population differentiation indicated by ddRAD analyses between nearby populations within putative species. This suggests that gene flow is limited, even between populations separated only by a few kilometres. This may lead to fast population differentiation, which in turn might drive speciation. Our data suggest that the species diversity of Paralimnadia in the Great Dividing Range is much higher than currently appreciated.
Speed of in vitro embryo development affects the likelihood of foaling and the foal sex ratio
Authors: Claes A. , Cuervo-Arango J. , Colleoni S. , Lazzari G. , Galli C. , Stout T. A.
Published: February 2020

The success of invitro embryo production (IVEP) in horses has increased considerably during recent years, but little is known about the effect of the speed of invitro embryo development. Blastocysts (n=390) were produced by intracytoplasmic sperm injection of IVM oocytes from warmblood mares, cryopreserved, thawed and transferred into recipient mares on Days 3, 4, 5 or 6 after ovulation. The time required for invitro-produced (IVP) embryos to reach the blastocyst stage was recorded (Day 7 vs Day 8). The likelihood of foaling was affected by the speed of invitro embryo development and recipient day after ovulation at transfer. The odds ratio for foaling was ~0.63 for transfer of Day 8 (46%) compared with Day 7 (56%) IVP blastocysts. The highest likelihood of pregnancy (72%) and foaling (60%) was observed when IVP blastocysts were transferred to recipient mares on Day 4 after ovulation. Finally, the sex (colt:filly) ratio was higher after transfer of Day 7 (71%:29%) than Day 8 (54%:46%) IVP blastocysts, suggesting that the speed of embryo development is sex dependent. In conclusion, the speed of invitro embryo development in our IVEP system affects the likelihood of foaling and the sex of the foal.
Interrogative marking in Chinese Sign Language
Authors: Lin Hao
Published: February 2020

Little research has been conducted on interrogative constructions in Chinese Sign Language (CSL) based on
naturalistic data. This paper presents a comprehensive investigation of CSL interrogative constructions. Based on findings from
naturalistic data, both manual and non-manual components of these constructions are described and analyzed, revealing a complex
system. Firstly, manual markers in content questions consist of two basic wh-signs, what and how-many, which
form two series of wh-compounds for more specific information retrieval. As for the manual marking of CSL polar questions, three
types of particles are attested, namely yes, a-not-a, and some negators.

Non-manual markers work as interrogative markers in two ways: morphologically and prosodically. The former way is
realized by mouthings, which can be equaled to suprasegmental markers like tones in spoken language. Prosodic non-manual marking
is mainly realized by brow movement while head tilt, eye gaze, etc. are excluded as optional. Considering the spread of brow
movement, we find that polar questions without particles are predominantly marked by brow raise spreading over the entire
sentence, while in interrogatives with manual markers, brow movement seems to be optional, since its frequency is lower and its
spreading behavior less regular. CSL is proposed to be a particle-rich sign language, and some speculations are offered on what
may cause this behavior.
Effect of Zr Content on Formation and Optical Properties of the Layered PbZrxTi1–xO3 Films*
Authors: Xu Yang-Yang , Wang Yu , Liu Ai-Yun , Shi Wang-Zhou , Hu Gu-Jin , Li Shi-Min , Deng Hui-Yong , Dai Ning
Published: February 2020

PbZrxTi1–xO3 (PZT) films are fabricated on F-doped tin oxide (FTO) substrates using chemical solutions containing PVP polymer and rapid thermal annealing processing. The dependence of the layered PZT multilayer formation and their optical properties on the Zr content x are examined. It is found that all the PZT films are crystallized and exhibit 110-preferred orientation. When x varies in the region of 0–0.8, the PZT films display lamellar structures, and a high reflection band occurs in each optical reflectance spectrum curve. Especially, those PZT films with Zr/Ti atomic ratio of 35/65–65/35 show clearly layered cross-sectional morphologies arranged alternatively by porous and dense PZT layers, and have a peak optical reflectivity of >70% and a band width of >45 nm. To obtain the optimal Bragg reflection performance of the PZT multilayers, the Zr content should be selected in the range of 0.35–0.65.
Enhanced laser-driven hadron sources with nanostructured double-layer targets
Authors: Fedeli L , Formenti A , Pazzaglia A , Arioli F M , Tentori A , Passoni M
Published: February 2020

Laser-driven ion sources are approaching the requirements for several applications in materials and nuclear science. Relying on compact, table-top, femtosecond laser systems is pivotal to enable most of these applications. However, the moderate intensity of these systems (I ≲ 1019 W cm−2) could lead to insufficient energy and total charge of the accelerated ions. The use of solid foils coated with a nanostructured near-critical layer is emerging as a promising targeted solution to enhance the energy and the total charge of the accelerated ions. For an appropriate theoretical understanding of this acceleration scheme, a realistic description of the nanostructure is essential, also to precisely assess its role in the physical processes at play. Here, by means of 3D particle-in-cell simulations, we investigate ion acceleration in this scenario, assessing the role of different realistic nanostructure morphologies, such as fractal-like foams and nanowire forests. With respect to a simple flat foil, the presence of a nanostructure allows for up to a × 3 increase of the maximum ion energy and for a significant increase of the conversion efficiency of laser energy into ion kinetic energy. Simulations show also that the details of the nanostructure morphology affect both the maximum energy of the ions and their angular distribution. Furthermore, combined 3D particle-in-cell and Monte Carlo simulations show that if accelerated ions are used for neutron generation with a beryllium converter, double-layer nanostructured targets allow to greatly enhance the neutron yield. These results suggest that nanostructured double-layer targets could be an essential component to enable applications of hadron sources driven by compact, table-top lasers.
A faster horse on a safer trail: generalized inference for the efficient reconstruction of weighted networks
Authors: Parisi Federica , Squartini Tiziano , Garlaschelli Diego
Published: February 2020

Due to the interconnectedness of financial entities, estimating certain key properties of a complex financial system, including the implied level of systemic risk, requires detailed information about the structure of the underlying network of dependencies. However, since data about financial linkages are typically subject to confidentiality, network reconstruction techniques become necessary to infer both the presence of connections and their intensity. Recently, several ‘horse races’ have been conducted to compare the performance of the available financial network reconstruction methods. These comparisons were based on arbitrarily chosen metrics of similarity between the real network and its reconstructed versions. Here we establish a generalized maximum-likelihood approach to rigorously define and compare weighted reconstruction methods. Our generalization uses the maximization of a certain conditional entropy to solve the problem represented by the fact that the density-dependent constraints required to reliably reconstruct the network are typically unobserved and, therefore, cannot enter directly, as sufficient statistics, in the likelihood function. The resulting approach admits as input any reconstruction method for the purely binary topology and, conditionally on the latter, exploits the available partial information to infer link weights. We find that the most reliable method is obtained by ‘dressing’ the best-performing binary method with an exponential distribution of link weights having a properly density-corrected and link-specific mean value and propose two safe (i.e. unbiased in the sense of maximum conditional entropy) variants of it. While the one named CReM
A
is perfectly general (as a particular case, it can place optimal weights on a network if the bare topology is known), the one named CReM
B
is recommended both in case of full uncertainty about the network topology and if the existence of some links is certain. In these cases, the CReM
B
is faster and reproduces empirical networks with highest generalized likelihood among the considered competing models.
Robust matching rules for real quasicrystals
Authors: Kalugin Pavel , Katz André
Published: February 2020

We consider the problem of extraction and validation of matching rules, directly from the phased diffraction data of a quasicrystal, and propose an algorithmic procedure to produce the rules of the shortest possible range. We have developed a geometric framework to express such rules together with a homological mechanism enforcing the long-range quasiperiodic order. This mechanism tolerates the presence of defects in a robust way.
Multidimensional Golay-Rudin-Shapiro structures
Authors: Ben-Abraham S I , David Amit
Published: February 2020

We extend the standard two-stage construction of the double-sided Golay-Rudin-Shapiro sequence to higher dimensions. We explicitly present the two-dimensional structure which is a convenient paradigm for all natural dimensions. We show also the three-dimensional four-symbol first-stage structure which we call proto-GRS and the final two-symbol Golay-Rudin-Shapiro structure. They may serve as models of disordered equicomposition alloys with some short range order of four and two components, respectively. Finally we show the essential features of the three- and four-dimensional structures.
Single crystal growth, crystal structure and surface characterisation of the binary phase Al45Cr7
Authors: Boulet P , de Weerd M C , Gaudry E , Ledieu J , Fournée V
Published: February 2020

A single crystal of the Al45Cr7 crystalline approximant has been grown using the Czochralski method. The structure of this phase has been resolved in the C2/m space group. Chromium atoms are systematically surrounded by Al atoms forming a distorted icosahedron. The icosahedra are linked either by a vertex or a triangular face or overlap along a five-fold axis. The (010) surface of this single crystal has been investigated under ultrahigh vacuum and shows a (1x1) termination at specific bulk planes. The terraces have a nanostructured appearance which is ascribed to the preservation of the CrAl12 clusters at the surface. Ab initio calculations shows the presence of a deep pseudogap at the Fermi level, due to both a Hume-Rothery effect combined with strong spd hybridization. The isoelectronic charge densities highlight the fact that the charges are mainly confined within the CrAl12 icosahedron providing support to a certain stability of the clusters which could explain the nanostructured surface morphology encountered. First results on Al thin film deposition on the (010) surface are also reported.
The Performance of Enhancement MOSFET—The trade-off on Transfer and Output Characteristics
Authors: Zhang Wentao
Published: February 2020

MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) is commonly used in electronic devices, and one of its major applications is power switching. The main research topic of the paper is to introduce the principles of functioning of n-channel enhancement MOSFET, discuss the trade-off in MOSFET when one factor is changed in order to improve one aspect of its performance and the method to improve the condition of trade-off. The author analyzes the trade-off problems when improving one of the transfer characteristics and output characteristics of MOSFET, respectively by decreasing the thickness of dielectric layer and changing the length and width of the channel. The author demonstrates the results will occur when decreasing the thickness of dielectric layer and length of channel, and increasing the width of channel; at last author introduces the method to relieve the problems of trade-off by applying third generation semiconductor.
The Difficulty and Solution of Mg-doped in GaN
Authors: Cheng Guoting
Published: February 2020

GaN could be the representative third generation semiconductors, it becomes a significant material in the optoelectronic and microelectronic devices. However, the production of atomic H dramatically increases the resistance of Mg-doped GaN Large amount of Mg-H complex are produced during the MOCVD process, dramatically reducing the performance of Mg-doped GaN. Low-Energy Electron Beam Irradiation (LEEBI) could eliminate surface H+ and thus reduce the resistance. Furthermore, Rapid Thermal Annealing (RTA) could decompose Mg-H complex, increasing the concentration of hole. By studying and improving every method, the electrical properties and optical properties are still not enough. Finally, the research points out the future direction of improving the performance of Mg-doped GaN.
Suggestions on Efficiency Droop of GaN-based LEDs
Authors: Ding Jixiang
Published: February 2020

InGaN/GaN-based light-emitting diodes (LEDs) are widely used in modern society and industry among different areas. However, InGaN/GaN LEDs suffer from an efficiency droop issue: The internal efficiency decreases during high current injection. The efficiency droop significantly affects the development of GaN-based LEDs devices in efficiency and light-output areas. Therefore, the improvement of the droop phenomenon has become a significant topic. This paper introduces several possible mechanisms of droop phenomenon based on different hypotheses including Auger Recombination, Carrier Delocalization and Electron Leakage. Furthermore, some proposals to mitigate efficiency droop, including semipolar LEDs, electron blocking layer(EBL), quaternary alloy and chip design will be discussed and analyzed. Also, it will provide some suggestions for the further optimization of droop phenomenon in each proposal.
Improve dielectric properties of Lamellar Calcium Niobate ceramics by spark plasma sintering
Authors: Liu Xinxin , Xie Xiong , Zhai Yunling , Wang Liang
Published: February 2020

The structure and dielectric properties of HCa2Nb3O10·1.5H2O (HCNO) and its exfoliated products (e-HCNO) ceramics were investigated. Where two-dimensional e-HCNO sheets were obtained by ion-exchange and exfoliating consequently. Spark plasma sintering (SPS) was introduced for products processing. After which, the dielectric constant of e-HCNO is 1300 and the loss is 0.002 at 2 M Hz. Compared to ordinary solid phase sintering, the dielectric constant of ceramics was found to be directly improved by the SPS processing.
Density functional theory study on bond dissociation energy of polystyrene trimer model compound
Authors: Huang Jinbao , Meng Hanxian , Cheng Xiaocai , Pan Guiying , Cai Xunming , Liu Jiangtao
Published: February 2020

The bond dissociation energy (BDE) of syndiotactic polystyrene(s-PS) was calculated by using four density functional theory methods, which were M062X, B3LYP, B3P86, BH and HLYP with different LANL2DZ, 6-31G(d), 6-31G(d, p), and 6-311++G(d, p) basis sets. The influence of these computational methods on the accuracy of the BDE of s-PS was analyzed. It was found that the BDE had a higher accuracy at B3P86/6-31G (d, p) level than other methods, and B3P86/6-31G (d, p) spent more less time to calculate the bond dissociation energy of s-PS, and the average of the C-C bonds’ BDE values calculated by B3P86/6-31G (d, p) is about 8.3 kJ/mol lower than the experimental value (310.0 kJ/mol), which is derived from the i-bond database. Besides, the bond dissociation energy values of the C-C bonds computed by M062X/LANL2DZ, B3LYP/6-31G(d), M062X/6-31G(d), B3LYP/LANL2DZ and BH and HLYP/6-311++G(d, p) methods were as follows: 330.8 kJ/mol, 345.3 kJ/mol, 283.2 kJ/mol, 267.6 kJ/mol, 267.4 kJ/mol. The calculation conclusion is drawn that different calculation methods with the same basis set have an obvious influence on the result of BDE values’ calculation. Finally, based on the calculation of bond dissociation energy of polystyrene, three possible reaction paths of polystyrene pyrolysis are designed to analyze the influence of bond dissociation energy on polystyrene pyrolysis.
Application of VSP well drive data in the prediction of complex carbonate reservoirs
Authors: Qin Li , Luo Kun , Cheng Lili
Published: February 2020

The qixia formation carbonate rocks in the northwest of sichuan are of great buried depth, thin reservoir thickness and strong heterogeneity. Therefore, VSP data are used to control the seismic data on the surface, VSP well drive data lay a good foundation for interpretation. Then, through waveform clustering analysis, favorable facies zones were developed. Secondly, natural faults are predicted based on maximum likelihood attribute technique. Finally, the reservoir quantitative prediction is carried out by using phase control inversion technique. The drilling well location is optimized based on reservoir and fracture prediction information, and the drilling effect is good, which provides strong technical support for subsequent exploration and development in this area.
Study on Thermal Storage Performance of Industrial Paraffin and Fatty Acid Binary Mixture
Authors: Yan Quanying , Fan Qingzhu , Jing Zhang
Published: February 2020

Taking the industrial paraffin and fatty acid binary mixture as the research object, the phase change temperature, latent heat of phase change and supercooling degree were studied by differential scanning calorimeter, aiming at reducing the application cost of simple fatty acid as phase change material, broadening the range of phase transition and increasing the amount of latent heat value of phase change. The results show that the paraffin-tannic acid and paraffin-lauric acid binary mixture reduces the phase transition temperature and increases the latent heat of phase change compared with the single fatty acid, which is suitable for the energy storage of the envelope structure. The phase transition temperature of paraffin-myristic acid, paraffin-stearic acid, paraffin-palmitic acid mixture is lower than 40 °C. Although it is lower than the phase transition temperature of single fatty acid under certain mixing ratio conditions, which is not suitable for application. In the energy storage of the structure, it can be used in other energy-saving systems such as phase change heat exchangers for waste heat recovery. Paraffin-tannic acid and paraffin-lauric acid binary mixtures are less subcooled and are ideal for energy storage in envelope structures.
Experimental and theoretical research on the thermal properties of carbonate mixtures
Authors: Yan Quanying , Wang Chenyu , Liu Chao , Zhang Jing
Published: February 2020

In this paper, Na2CO3, Li2CO3 and K2CO3 were selected to prepare carbonate mixtures according to different proportions. The thermal property and stability of the samples were tested by differential scanning calorimeter (DSC). The phase change temperature and latent heat of carbonate mixtures were calculated by theoretical formula, and compared with the experimental data to verify whether the theoretical formula are applicable in the field of high temperature molten salt. The results show that the melting point of carbonates which melted together is about 400°C. And the melting point of ternary carbonates is lower than the single component. The initial crystallization points of some samples are higher than the melting points. The differences between the melting point and the primary crystallization temperature are 5∼20°C. The phase change latent heat of the carbonate mixtures is lower than the single component’s. The latent heat of melting is more than the latent heat of solidifying. The DSC testing curves of the carbonate mixtures are almost coincident. The stability of mixed carbonate is very good. This experiment will provide reference and basis for its application in solar thermal power generation.
Research on the change rule of microbial community in the microbial flooding process of Baolige oilfield
Authors: Wang Guan , Duan Lisha , Han Feng , Wang Rui , Liu Shasha , Lei Xiaoyang , Jing Jizhe , Gu Yi , Lei Yuchao
Published: February 2020

In Baolige oilfield, through the research and field implementation of microbial flooding technology, some application effects had been achieved. In order to further improve the implementation effect, the microbial community in the produced liquid during microflooding was tracked, monitored and analyzed by high-throughput sequencing (NGS). The results showed that the microflora diversity was plentiful. The species diversity after micro-flooding was higher than that during micro-flooding. In microbial flooding stage, due to replenish nutrients and exogenous bacteria to reservoir, the advantage bacteria group was mainly Pseudomonas, Acinetobacter, Thauera and Wallingella. After the microbial flooding, due to stop supplying nutrients, the bacteria community changed. The relative abundance of hydrocarbon-degrading bacteria declined and that of anaerobic aerogen increased.
Adsorption Properties of Sulfonylcalix[4] arenetetrasulfonate-loaded Resin towards Strontium(II) from Aqueous Solutions
Authors: Liu Cong , Su Guofeng
Published: February 2020

Sulfonylcalix[4]arenetetrasulfonate-loaded D201 composite (SCAS-D201) was prepared by a simple method and used as an adsorbent for removal of Sr(II) from aqueous solutions. The adsorption of the Sr(II) onto SCAS-D201 composite as a function of contact time, pH, Sr(II), temperature concentration was investigated. Results show that the adsorption capacities of SCAS-D201 composite towards Sr(II) reached a maximum at pH values of ∼7. The adsorption has reached equilibrium within 120 min and the kinetics can be well fitted by a pseudo-second-model. The adsorption isotherm was well fitted by the Langmuir model, and the maximum value of adsorption capacity of the adsorbent was 76.43 mg·g−1. Possible adsorption mechanisms are also analysed.
Application of F− modified Fe-SAPO-34 as a New Photo-catalyst in Printing and Dyeing Wastewater Treatment
Authors: Cao Ying , Shen Taoyi , Guo Weilin , Song Xianzhen , Kong Lingxue , Wang Lijun
Published: February 2020

The development of new photocatalysts with a wide range of applications is one of the important challenges in the field of photocatalysis research. In this thesis, ferric phosphate was used as a transition metal salt, and HF was used as a mineralizer to prepare Fe-SAPO-34 photocatalyst, which was applied to the degradation of organic dye wastewater. The materials were characterized by XRD, SEM and other characterization methods. After the photocatalyst is supported on the molecular sieve, it usually exhibits excellent performance in catalyzing the degradation of different dyes, and generally higher than the catalytic efficiency of the unmodified catalyst under the same conditions.
Fabrication of Ag-incorporated TiO2 film on TiNb substrate and evaluation on its antibacterial activity against E. coli
Authors: Xiaogang Liao , Gang Li , Xiaoqian Xiang , Tao Fu , Guo Tang
Published: February 2020

For the purpose of endowing TiNb alloy with antibacterial function, a two-step strategy was proposed to fabricate Ag-incorporated TiO2 film on TiNb substrate in this study. X-ray diffraction (XRD), Field-emission scanning electron microscopy (FESEM) and X-ray photoelectron microscopy (XPS) were used to characterize the crystal phases, morphologies and chemical compositions of the samples. The results showed that a layer of anatase TiO2 film with two kinds of morphologies was formed by hydrothermal treatment of TiNb alloy in NH4F-H2O2 solution. When the as-obtained TiNb-based TiO2 film was subjected to a further ultraviolet light irradiation in AgNO3 solution, metallic Ag granules with size range from 60 nm to 1.3 μm were uniformly deposited on the surface of TiO2 particles. Escherichia coli (E. coli) was selected as a model to estimate the bacteriostatic effect of the Ag-TiO2 film. The experimental result indicated that Ag-incorporated TiO2 exhibited excellent antibacterial activity against E. coli. It suggests that this two-step method for preparation of Ag-TiO2 composite film may provide an alternative strategy to reduce bacterial infection for Ti-implants in clinical application.
Micellar and Interfacial Behavior of Mixed Systems Containing Anionic-nonionic Gemini Surfactant
Authors: Chen Hong , Zhu Baowei , Liu Haiyan
Published: February 2020

The Anionic-nonionic Gemini Surfactant oxalamide polyoxyethylene lauryl ether(9)succinate sodium sulfonate(OPLES-9) was synthesized. It was mixed with the anionic surfactant sodium lauryl sulfate(SDS) and the nonionic surfactant dodecanol polyoxyethylene(9) ether (AEO9) respectively in different ratios to enhance application performance. The experimental results showed that the surface performance of the mixed systems was more superior to the relevant single surfactants. The mixed critical micelle concentration (CMC) of the binary surfactant systems was determined by surface tension measurement. Critical micelle concentration of mixed system reached the minimum 0.146mmol·L−1 when the molar fraction of OPLES-9 to SDS was 1:1. Critical micelle concentration of OPLES-9/AEO9 mixed system reached the minimum 0.259mmol·L−1 when the molar fraction of OPLES-9 to AEO9 was 0.9:1.
Electrochemical Decontamination of Platinum Nanocrystals and its Applications for Methanol Electrooxidation
Authors: Lu Leilei , Zhu Mi , Zheng Yaoping , Yang Rong
Published: February 2020

Polyvinylpyrrolidone (PVP) is an effective surface-capping agent for engineering metal surface structure but is hardly to be thoroughly removed. In this study, the electrochemical treatment was applied for the decontamination of polyvinylpyrrolidone (PVP) on platinum (Pt) nanocrystals. Spherical, cubic, octahedral and cuboctahedral Pt nanocrystals were prepared by the colloidal method with PVP K30 as the capping agent. Electrochemical decontamination of Pt nanocrystals was performed by using square-wave potential steps and methanol electrooxidation was used as a probe reaction. High-frequency potential steps were set up between a high voltage and a low voltage to avoid surface distortion. Cyclic voltammetry (CV) and chronoamperometry measurements were used to evaluate the catalytic activity of the cleaned Pt nanocrystals for methanol. The results showed that electrochemical decontamination was an effective way to clean Pt nanocrystals and the cuboctahedral Pt nanocrystals displayed the best electrocatalytic activity for methanol electrooxidation.
Welding performance of the dissimilar joints of Fe-Mn-Si alloy and 304 stainless steel
Authors: Liu Linlin , Du Jinqiao , Zhou Chaoyu
Published: February 2020

The dissimilar joints of Fe-17Mn-5Si-10Cr-5Ni memory alloy and 304 stainless steel were welded by 5 kw transverse flow CO2 laser. The microstructure, morphology and composition of the welding of the dissimilar joints were analyzed by metallographic microscope, field emission scanning electron microscopy. The results showed that the crystals of dissimilar joints of Fe-17Mn-5Si-10Cr-5Ni memory alloy and 304 stainless steel were symmetrically distributed on both sides of the joint weld center. At Fe-17Mn-5Si-10Cr-5Ni memory alloy close to the side of the weld, ε martensite phase was also found, which was caused by the γ→ε martensite transformation induced by the residual stress. The distribution of dissimilar joint weld elements was in zones obviously, the distribution mode was related to the unique keyhole effect of laser welding, and the weld center metal was still Fe-Mn-Si memory alloy, which had the characteristic of the inverse phase transition of the stress induced martensite.
Unique hierarchical Sn3O4 nanoflowers decorated with ZnO nanoparticles and their formaldehyde gas sensing properties
Authors: Wang Lei , Li Yang , Gao Song , Yue Wenjing
Published: February 2020

Gas sensors with high response are highly desirable for the detection of harmful gases in real-time. Herein, the ZnO nanoparticles decorated hierarchical Sn3O4 nanoflowers are synthesized by a hydrothermal method. The gas sensor based on the ZnO/Sn3O4 composites exhibits excellent sensing properties to formaldehyde with a low operating temperature of 180°C. Specifically, the sensor has a response value of 44 for 100 ppm formaldehyde and a fast response time of 5 s. Moreover, it is noteworthy that the proposed gas sensor shows a wide detection range and a low detection limit of 1 ppm. Besides, the ZnO/Sn3O4 sensor exhibits good selectivity for formaldehyde and perfect reproducibility. The sensing mechanism of the gas sensor is discussed, and the heterojunction between ZnO and Sn3O4 enhances the sensing performance of the proposed gas sensor.
Preparation of nanofluids and their applications in enhanced CO2 absorption
Authors: Han Huiyu , Ma Xiaoxun , Xu Long
Published: February 2020

Nanofluids opened up research in the field of thermal energy and mass transfer engineering when it was first proposed by American scientist Choi. In this paper, a two-step method was used to prepare stable nanofluids. Enhancement factor was introduced to study the enhancement of CO2 absorption by nanofluids under different experimental conditions. The results show that the enhancement of the three nanoparticles in the same solid content is TiO2 > Al2O3 > SiO2; The optimum solid content of SiO2 and Al2O3 is 0.8 g/L, and the optimum solid content of TiO2 is 0.6 g/L; Within the scope of this study, the larger the particle size, the better the absorption effect. As the organic amine concentration increases, absorption of solution improves.
Formation technology of effective electrode materials based porous silicon with platinum metal nanoparticles for autonomous energy systems
Authors: Ragutkin A V , Antropov A P , Lebedeva M V , Sigov A S , Yashtulov N A
Published: February 2020

In this work the effective electrode materials for autonomous energy sources based on porous silicon modified by platinum nanoparticles have been obtained. The functional characteristics of the electrodes have been studied by transmission electron microscopy and voltammetry methods. The electrode materials based on porous silicon had demonstrated high catalytic activity in fuel cells with hydrogen oxidation.
Automatic Lab scale equipment for continuous HMF production in biphasic systems
Authors: Klushin V A , Chizhikova A A , Gorchakov V V , Smirnova N V
Published: February 2020

An automatic lab scale equipment for continuous HMF production by the dehydration of fructose with homogeneous catalysis in biphasic systems (water solution - MIBK) was designed, manufactured and tested. The dependencies of the HMF yield on the process parameters were studied. The feed rate of fructose varied from 50 to 100 g·h−1, the extractant (MIBK) flow rate from 0.5 to 1.4 L·h−1 and the process temperature was maintained in the range from 50 to 87 °C. The maximum productivity of the automatic lab scale equipment 33.6 g·h−1 with a high HMF yield 48 % is achieved with the following process parameters - 87 °C, the fructose feed rate 100 g·h−1 and the extractant flow rate 1 L·h−1. This automatic lab scale equipment may be prospectively used for the kilogram scale HMF synthesis.
Nafion-carbon containing nanocomposite materials with high catalytic activity for portable energy sources
Authors: Lebedeva M V , Ragutkin A V , Antropov A P , Yashtulov N A
Published: February 2020

In this work the electrode materials on combined polymer-carbon matrix-supports modified by bimetal platinum-ruthenium nanoparticles have been formed. The functional characteristics of the electrodes have been studied by atomic force microscopy, scanning electron microscopy and voltammetry methods. The catalytic activity of the synthesized composites in the methanol oxidation reaction had been studied.
Modeling of atomic interactions in carbon nanotubes
Authors: Chwał M , Muc A
Published: February 2020

This work concerns atomic potentials applied in the description of carbon nanotubes mechanical behavior. The explicit relations of interatomic forces for different interatomic potentials have been derived. The fluctuations in the values of interatomic potential, interatomic force, elastic constant and Young’s modulus have been put forward to elucidate the similarities and differences between potentials. The present analysis may be helpful in the equivalent continuum modelling of carbon nanotubes and nanocomposites.
Numerical Simulation of Hydraulic Fracturing Effect Based on Abaqus
Authors: Li Xinyong , Qu Ximo , Sun Ting , Wang Jie , Fang Haoqing , Liu Zhiyuan , Luo Pandeng , Zhao Bing , Zhang Wenzhe
Published: February 2020

This study simulates the hydraulic fracturing process based on ABAQUS, and obtains the results of hydraulic fracturing fracture propagation under the influence of multi-parameters. Our research shows that:The effect of reservoir modification increases with the increase of injection rate of fracturing fluid. Under the condition of 8m3/min or above, the fracture can communicate with the fault zone 100m away from the bottom of the well. Under the condition of 10cP, the effect of fracture propagation in formation is good. Under the condition of 50cP, the effect of fracture propagation in fracture zone is good. Under the condition of 200cP, the effect of crack propagation is poor. When the injection volume of fracturing fluid is between 0 and 1440m3, the effect of fracture propagation increases gradually. When the injection volume of fracturing fluid is larger than 1440m3, the contribution of continuous injection become weak. The maximum vertical crustal stress results in the fracture extending to the depth. The maximum horizontal crustal stress results in the horizontal propagation of fractured fractures. This study analyzed the influence of formation parameters and hydraulic fracturing parameters on fracture propagation. It also plays an active role in predicting the effect of hydraulic fracturing.
Review of the Surface Treatment s of Plant Fibers as Reinforcements in Polymer Composites
Authors: Zhu Z H , Zhang Y , Zhang N , Wang T , Hao M Y
Published: February 2020

The poor compatibility between plant fiber and polymer matrix leads to many defects and deficiencies in plant fiber reinforced polymer composites. Various common physical or chemical treatments of plant fibers are listed in this paper. Surface treatments can improve the interface bonding of fibers and matrix, whereas the mechanical properties of plant fibers will be greatly reduced after treatments. How to retain the properties of plant fibers to the greatest extent and improve the comprehensive properties of plant fibers reinforced polymer composites is a problem that needs attention and urgent solution when treating plant fibers by various treatments.
Magnetised photocatalyst TiO2/Fe3O4 nanocomposite capable to photodegrade organic dye
Authors: Tan Thian Khoon , Khiew PoiSim , Chiu WeeSiong , Chia ChinHua
Published: February 2020

In this study, methylene blue (MB) is used as a measure of the photocatalytic capabilities of the prepared TiO2/Fe3O4 photocatalyst nanocomposite. The nanocomposite was suspended in the dye aqueous solutions placed in a UV chamber under UV-C (254 nm) light irradiation. The TiO2/Fe3O4 nanocomposite was characterised by XRD, FESEM, TEM and EDX analysis. The TiO2/Fe3O4 nanocomposite crystal structure retained TiO2 pure anatase of tetragonal crystal structure (SG: I4/
a

md) and Fe3O4 cubic spinel crystal structure with average crystalline size of (62.1 ± 5.7) nm. The optimum performance of the magnetic nanocomposite was monitored through few categories, such as concentration of photocatalyst, doping amount of Fe3O4 nanoparticle into the nanocomposite and sintering temperature. The TiO2/Fe3O4 nanocomposite optimum loading was detected at 3.0 wt%. The nanocomposite performed well at 1 wt% of Fe3O4 doping and 350 °C of sintering temperature. The reliability of the TiO2/Fe3O4 nanocomposite was also conducted where it was successfully repeated for at least 3 times with no obvious changes observed in the degradation efficiency.
A Synchrotron Study of Molecular and Chemical Interaction at the Dental Material/Biomimetic Composite/Native Hard Dental Tissue Interface
Authors: Goloshchapov D , Kashkarov V , Ippolitov Yu , Ippolitov I , Vongsvivut J , Seredin P
Published: February 2020

Based on the technology of molecular multidimensional IR- synchrotron visualization, the paper explores integration of a new generation of biomimetic composites that regenerates a mineral organic dental enamel complex with native human hard dental tissues and dental cement. The data of spectral molecular visualization was obtained from the area of the healthy hard tissue (enamel/dentine) – biomimetic transition layer – dental material/adhesive interface. The resulting data is indicative of chemical differentiation of functional groups of all the materials at the biomimetic system/natural hard tissue and prove the chosen method to be effective in analyzing integration of dental concrete and new generation biomimetic composites.