bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of mean flow on mutual radiation resistances of a rectangular plate
Authors: Zhu Liping
Published: June 2019

Very few investigations have considered the effects of fluid convection on the mutual- radiation resistance, which could be important in stationary fluids. In this work, we quantified the effects of a convected fluid on the radiation resistances including self- and mutual radiation resistances. We derived the non-dimensional modal impedance in the presence of mean flow based on an expansion in the panel mode of a simply supported plate. Then we compared the self-radiation resistances with the previous reports and analyzed the effects of flow on mutual radiation resistances. The results show that the radiation efficiency increases with the flow velocity, which compare very well with the previous reports. The flow introduces a strong coupling between modes that weakly coupled in no-flow case and with the increase of flow velocity. This coupling effect increases until Mach number (M) reaches 0.5 and then decreases. For the modes with the same parity indices, the flow shifts coupling lobes toward lower frequency with the increase of flow velocity due to the shift of critical frequency of higher mode radiation resistance, and the degree of coupling change is consistent with the change of critical frequency of the higher mode self-radiation resistance.
Removal of boron from metallurgical grade silicon by CaO-SiO2 based slags
Authors: Hou Yong , Wu Yue-dong , Zhang Guo-Hua , Chou Kuo-Chih
Published: June 2019

Slag refining is one of the most effective methods to remove boron from metallurgical grade silicon (MG-Si). In this paper, the removal of boron from metallurgical grade silicon was proposed by adding CaF2, BaO or rare earth oxides (La2O3 and CeO2) to CaO-SiO2 based slags. The effects of the BaO content, the CaF2 content, the rare earth oxides content, the molar ratio of CaO to SiO2 and the mass ratio of slag to silicon on the partition coefficient of boron (LB) between slag and silicon are investigated. The results show that LB has a maximum value of 5.17 in 45% CaO-45% SiO2-10% BaO slags at 1550 °C after reacting for 6 h with a slag to silicon mass ratio of 2. Besides, it is found that the addition of La2O3 or CeO2 shows better de-boronization ability compared with the addition of BaO.
Effect of microwave irradiation on the grinding and magnetic separation characteristics of vanadium titano-magnetite
Authors: Wang Junpeng , Jiang Tao , Liu Yajing , Xue Xiangxin
Published: June 2019

In this study, the influence of microwave irradiation on the grinding characteristics and magnetic separation of vanadium titano-magnetite (VTM) was investigated, including the effects of microwave power, microwave irradiation time, and particle size of VTM. The particle size distribution of the ground product and Fe grade in magnetic fraction of the untreated and microwave-treated VTM were obtained. Grinding experiment showed that the microwave irradiation could improve the grindability of VTM, thus increasing the specific rate of breakage (S1) value and the weight percentage of the fine ground product significantly. With increasing microwave irradiation time and particle size of VTM, the increment in grindability of VTM was improved. No obvious difference was observed in the particle size distribution of the fine ground product between the untreated and microwave-treated VTM. The magnetic separation tests confirmed that the Fe grade of the magnetic fraction increased from 51.70% for untreated VTM to 53.78% by microwave irradiation. According to X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and scanning electron microscopy (SEM) analyses, the dominant mechanisms that improved the grindability and liberation of VTM under microwave irradiation included the microwave selective heating the valuable mineral within the VTM and the micro-fractures between mineral and gangue that were induced by the thermal stress.
Advances in thermal level measurement techniques using mathematical models, statistical models and decision support systems in blast furnace
Authors: Agrawal Ashish , Kothari Anil Kumar , Kumar Arun , Singh Manish Kumar , Dubey Shivendra Kumar , Ramna R.V. , Nath Shambhu
Published: June 2019

The estimation of thermal level in blast furnace is of utmost importance, because the processes occurring inside the blast furnace are complex in nature and any drift in thermal level could lead to abnormal furnace state. The present review is made to understand the methods for estimating thermal level in blast furnace, and the drift in estimation of the thermal level. The thermal level estimation is divided into 3 categories, viz. mathematical models, statistical models and decision support systems. The mathematical models are based on the first principle of thermodynamics and give an estimate of the thermal level in blast furnace. On the other hand, the statistical models are mainly the data-based approach that uses the historical data to predict the instability in blast furnace. Lastly, the decision support systems are the prescriptive models that give the recommendations for making the necessary corrections in the process parameters to avoid occurrence of abnormality in blast furnace. Further, the drifts in estimation of thermal level by these techniques are identified and recommendations are made to improve the accuracy of thermal level estimation. The recommendations to control thermal level in blast furnace are provided which when applied in the industrial blast furnace, can avoid the occurrence of catastrophic condition.
Ernährungstherapie des Intensivpatienten
Authors: Koch Alexander , Bündgens Lukas , Tacke Frank
Published: June 2019

Nutritional therapy is an elemental component of intensive care treatment. Therapeutic goals are the enteral or parenteral provision of calories, protein, electrolytes, vitamins and trace elements. Pathophysiologically, metabolism in critical illness is characterized by a catabolic stress status. This results from an underlying systemic inflammatory response and is associated with increased rate of infections, multiple organ failure and unfavourable outcome. In this article, the principles and strategies of nutrition support therapy in critically ill patients are presented, based on current guidelines.
Bewusstseinsstörungen und Koma
Authors: Erbguth Frank
Published: June 2019

Cerebral diseases such as epileptic seizures, cerebral hemorrhages or meningoencephalitis are the primary cause of approximately 50 % of non-traumatic acute disorders of consciousness. For the differential diagnosis, history and other symptoms are important such as hemiplegia, signs of brain stem dysfunction, meningism or headache. Metabolic, endocrinologic, toxicologic or electrolytic causes of coma usually can be diagnosed by laboratory examinations. Anamnestic informations, body inspection, clinical neurological examination as well as laboratory and imaging findings have to be added and categorized by a multilevel composition to establish a conclusive diagnosis. Simultaneously therapeutic measures for suspected primary cerebral diseases must be initiated, for example a rapid antibiotic treatment in case of a possible bacterial meningitis. A fast and structured diagnostic approach is crucial for ensuring a good prognosis and helps to miss relevant diagnostic steps. Potential diagnostic and therapeutic pitfalls must be kept in mind.
Das kardiorenale Syndrom
Authors: Scurt Florian Gunnar , Kuczera Tim , Mertens Peter René , Chatzikyrkou Christos
Published: June 2019

Chronic heart failure is associated with high morbidity and mortality and is the most common hospital diagnosis for elderly patients. Concomitant or superimposed acute or chronic kidney injury, as is the case with cardiorenal syndrome, has a dramatic impact on the outcome. The inhibition of the neurohumoral axis and the adequate treatment of hypervolemia are fundamental elements of modern cardiac insufficiency therapies. In addition to optimal conservative therapy, there are other options: VAD implantation, hemodialysis and peritoneal dialysis. The PD offers biological and clinical benefits as an additive therapy for the treatment of patients with heart failure, refractory hypervolemia and non-urinary renal failure.
Application of Carbon Nanotubes in Breast Cancer Therapy
Authors: Tajabadi Mahdis
Published: June 2019

Conjugated single-walled carbon nanotubes (SWNT) have been shown to be promising in cancer-targeted accumulation and is biocompatible, easily excreted, and possesses little toxicity. The present study aims at reviewing the recent advancements in carbon nanotubes especially SWNT for improving the treatment of breast cancer. Nanotube drug delivery system is a potential high efficacy therapy with minimum side effects for future tumor therapy with low doses of drug.
Radio- und Photosensitivierung von Plasmid-DNA durch den
DNA-bindenden Liganden Propidiumiodid: Untersuchungen zur
Auger-Elektronen-Induktion und zum Nachweis von
Cherenkov-Strahlung
Authors: Kotzerke Jörg , Runge Roswitha , Götze Pauline , Wunderlich Gerd , Enghardt Wolfgang , Freudenberg Robert
Published: June 2019

Ziel Untersucht wurde, ob Propidiumiodid (PI) die DNA-schädigende Wirkung
von ionisierender und nicht ionisierender Strahlung (Röntgenstrahlung, Alpha-,
Beta-, Auger-Elektronen-Strahlung bzw. Licht diverser Wellenlängen) verstärken
kann. Diese biophysikalische Versuchsanordnung ermöglicht es zu überprüfen, ob
Cherenkov-Strahlung in relevantem Umfang via photodynamischer Effekte und
erhöhter DNA-Schädigung nachweisbar ist.

Material und Methoden Konformationsänderungen der Plasmid-DNA durch
DNA-Schäden wurden mittels Gelelektrophorese und Fluoreszenzfärbung detektiert
und quantifiziert. Wasserstoffperoxid, Zinndichlorid und Dimethylsulfoxid wurden
als chemische Modulatoren, Tc-99m, Re-188, Ra-223 und Röntgenstrahlung (32 kV
und 200 kV) zur Bestimmung der Radiotoxizität und Licht (λ = 254 nm, 366 nm und
530–575 nm) zur Bestimmung der Phototoxizität eingesetzt.

Ergebnisse Die Radiotracer und die Röntgenstrahlung verursachten
dosisabhängige DNA-Schäden. PI fungierte nicht als Radio-Sensitizer bei den
Radionukliden und nur in geringem Maß bei Röntgenstrahlung. Die Phototoxizität
war abhängig von der Wellenlänge. Licht im Wellenlängenbereich von 530–575 nm
(VIS) resultierte in Kombination mit PI in direkten DNA-Schäden. Die Ausbeuten
der Cherenkov-Strahlung lagen weit unter der Photonen-Emission der
Lichtbestrahlung und konnten daher von der Radiotoxizität nicht unterschieden
werden.

Schlussfolgerung PI bindet an Plasmid-DNA, ist nicht chemotoxisch und
steigert kaum die Radiotoxizität. Die Phototoxizität und die Wirkung von PI sind
abhängig von der Wellenlänge. Keine Art der Energiezufuhr konnte via PI eine
Auger-Elektronen-Kaskade induzieren. Auch eine erhöhte DNA-Schädigung durch
photodynamische Effekte via Cherenkov-Strahlung war nicht nachweisbar.
Cytotoxic Cardenolides from the Leaves of Acokanthera oblongifolia
Authors: Pecio Łukasz , Hassan Emad M. , Omer Elsayed A. , Gajek Gabriela , Kontek Renata , Sobieraj Andrzej , Stochmal Anna , Oleszek Wiesław
Published: June 2019

Three previously undescribed cardenolides, acovenosigenin A 3-O-α-L-acofriopyranoside (1), 14-anhydroacovenosigenin A 3-O-[β-D-glucopyranosyl-(1″→4′)-O-α-L-acofriopyranoside] (2), and 14-anhydroacovenosigenin A 3-O-[β-D-glucopyranosyl-(1″→4′)-O-α-L-acovenopyranoside] (3), together with the two already known ones, 14-anhydrodigitoxigenin 3-O-β-D-glucopyranoside (4) and acospectoside A (5), were isolated from the leaves of Acokanthera oblongifolia. The influence of cardenolides 1 – 3 and acovenoside A (found in the Acokanthera genus) on three cancer cell lines (HT29, HCT116, and AGS) was also investigated. The most promising results, in comparison with oxaliplatin, were obtained for compound 1, which was found to be highly cytotoxic for all tested cell lines, HT29 (IC50 = 63.49 nM), HCT116 (IC50 = 67.35 nM), and AGS (IC50 = 80.92 nM). Unfortunately, 1 also showed similar toxicity towards normal lymphocytes (IC50 = 98.03 nM).
Certified Diabetes Educator: An Important Aid in Improving Patient Care in Diabetes
Authors: Joshi Ameya , Shaikh R. D. Sana N.
Published: June 2019

Diabetes mellitus is a chronic disease in which education plays a vital part. However, in India that is overburdened with diabetes has short of diabetes educators. Care for diabetes is limited by the adverse physician-to-patient ratio and lack of trained paramedical personnel. The following review focuses on role of diabetes educators in diabetes care and their current status in India.
Osseous Sarcoidosis with a Solitary Lytic Skull Lesion: A Case Report
Authors: Thirunavukarasu Vignaraja , Thirunavukarasu Caitlin , Willis Timothy , Tsahtsarlis Antonio
Published: June 2019

Bone sarcoidosis is an uncommon manifestation of the multisystemic disease with skull involvement being rare. We present the case of a 32-year-old female who was referred by her General Practitioner with a left calvarial lesion on a background of previous unilateral 7th nerve palsy and diabetes mellitus. Images demonstrated a left frontoparietal calvarial osteolytic lesion. She underwent resection by the neurosurgical team with histopathological study revealing noncaseating granulomas, consistent with sarcoidosis. Given absence of other systemic features of sarcoidosis, she did not undergo systemic treatment.
HAEMOcare: The First International Epidemiological Study Measuring Burden of Hemophilia in Developing Countries
Authors: Gupta Naresh , Benbouzid Abderrahmane , Belhani Meriem , El Andaloussi Mohammed , Maani Khadija , Wali Yasser , Benchikh El Fegoun Soraya , Saad Hossam Ali , Mahlangu Johnny
Published: June 2019

Introduction Optimizing hemophilia care remains challenging in developing countries. Burden-of-disease studies are important to develop strategies for improving hemophilia care.

Aim The HAEMOcare study evaluated the factors contributing to hemophilia-related orthopedic disease burden in developing countries.

Methods HAEMOcare was a noninterventional, cross-sectional, epidemiological study conducted in Algeria, India, Morocco, Oman, and South Africa. Male patients with severe hemophilia (N = 282) aged ≥6 years, without or with inhibitors, being treated on-demand for bleeding were included. Hemophilia-related orthopedic clinical and functional status was assessed using the Hemophilia Joint Health Score (HJHS), radiological status with the Pettersson Score, and quality of life with the EuroQol five-dimension questionnaire (EQ-5D-3L). Direct and indirect economic costs of hemophilia care were also calculated.

Results Patients (mean [standard deviation, SD] age: 20.8 [10.6] years) experienced a mean annualized bleeding rate of 25.8. Overall mean (SD) HJHS and Pettersson score were 17.9 (12.8) and 15.0 (13.5), respectively; scores were similar between patients without or with inhibitors (p = 0.21 and 0.76, respectively). Approximately 70% of adults reported problems relating to pain/discomfort and mobility parameters in the EQ-5D-3L. Mean distance to a hemophilia treatment center (HTC) was 79.4 km. As expected, total costs of hemophilia were statistically significantly higher in patients with inhibitors versus without inhibitors (p = 0.002).

Conclusion Inadequate access to HTCs and expert care, along with high bleeding rates, led to equivalent hemophilia-related orthopedic morbidity between hemophilia patients without and with inhibitors. HAEMOcare documented the economic and disease burdens associated with suboptimal hemophilia care in developing countries.
Pelvic Actinomycosis Mimicking Pelvic Malignancy
Authors: Saramago Sofia Modesto , Cominho Joana Catarina , Proença Sara Soares Marques , Conde Pedro João Casado , Nunes Filomena Maria Pinheiro
Published: June 2019

Asymptomatic female genital tract colonization with Actinomyces spp is not uncommon, particularly among intrauterine device users. Pelvic actinomycosis is an extremely rare disease. The clinical picture can resemble an advanced ovarian malignancy. We report a case of pelvic actinomycosis mimicking ovarian malignancy diagnosed postoperatively. Preoperative diagnosis is possible if there is a high index of suspicion, obviating extensive surgery and preserving fertility, since long term antibiotic treatment can be completely effective. Pelvic actinomycosis should be included in the differential diagnosis of women presenting a pelvic mass, especially if there is intrauterine device use history.
Pregnancy Among Women with Kidney Transplantation: A 20-Years Single-Center Registry
Authors: Mariano Stephanye , Guida Jose Paulo de Siqueira , Sousa Marcos Vinicius de , Parpinelli Mary Angela , Surita Fernanda Garanhani , Mazzali Marilda , Costa Maria Laura
Published: June 2019

Objective To assess maternal and perinatal outcomes in pregnancies after kidney transplantation in a tertiary center in Brazil.

Methods Retrospective cohort of pregnancies in women with kidney transplantation at the Universidade Estadual de Campinas, from January 1995 until December 2017. Medical charts were reviewed, and maternal and perinatal outcomes were described as means and frequencies. Renal function and blood pressure were evaluated during pregnancy and postpartum.

Results A total of 22 women had at least 1 pregnancy during the considered time interval, and 3 of them had > 1 pregnancy, totalizing 25 pregnancies. The mean age at transplantation was of 24.6 ± 4.2 years old, and the mean time interval until pregnancy was of 67.8 ± 46.3 months. The most frequent complication during pregnancy was hypertension, which affected 11 (64.7%) women. The gestational age at delivery was 34.7 ± 4 weeks, and 47% of these pregnancies were preterm (< 37 weeks). A total of 88.2% of the women delivered by cesarean section. Renal function, measured by serum creatinine, remained stable during pregnancy, and the systolic blood pressure increased significantly, while the diastolic blood pressure did not differ during pregnancy.

Conclusion Pregnancy after kidney transplantation is a rare event. Pre-eclampsia and prematurity were frequent complications, and cesarean section rates were very high. A specialized antenatal and postpartum care with a multiprofessional approach and continuous monitoring of graft function are essential for the early diagnosis of complications and improved outcomes.
Morphological and Clinical Significance of Thebesian Valve Guarding Ostium of Coronary Sinus
Authors: Kulkarni Veena , Kulkarni Vijay K. ,   Vagdevi H.S.,   Vasanth Kumar H.S.
Published: June 2019

Background The advent of novel therapeutic techniques require cannulation of coronary sinus. The Thebesian valve guarding the ostium of coronary sinus can pose practical difficulties during such procedures.

Aim With this background we undertook a detailed study of the morphological features of Thebesian valve, so that we can substantially evaluate the clinicoanatomical importance of it.

Materials and Methods Fifty human dissected cadaveric heart specimens were selected from the department of anatomy, SDM College of Medical Sciences and Hospital, Dharwad. The location of ostium of coronary sinus and the occurrence of the Thebesian valve and its shape, composition, and extent of occlusion of the ostium were carefully observed and noted.

Results Our observations revealed that 90% of specimens had the Thebesian valve guarding the opening of coronary sinus. It was semilunar in shape in 74% of specimens. The valve was membranous in composition in 46% of specimens. Among these, in 26% of specimens the valve almost covered more than 50% of the ostium of coronary sinus indicating moderate to severe occlusion.
Surgical Treatment of Tracheal Lipoma after Multiple Bronchoscopy Interventions and Placements of a Tracheal Stent
Authors: Zhang Xiaoming , Ji Tao , Yang Longhai , Liu Yi , Lin Hongsheng , Pan Huiyu , Zhou Zizi
Published: June 2019

Background The majority of adult primary tracheal tumors are malignant; however, as one type of benign tumors, lipoma is extremely uncommon.

Case Description We report a case where lipoma was first misdiagnosed as bronchial asthma, followed by sudden aggravation of dyspnea after trauma, and computed tomography (CT) examination of the neck and chest confirmed a tracheal tumor. Through multiple bronchoscopy interventions and placements of a tracheal stent, little therapeutic benefit was discovered, and resection of the tracheal tumor combined with tracheal end-to-end anastomosis was performed to ultimately achieve a cure.

Conclusion Primary tracheal tumors should be highly suspected in patients with recurrent and gradually worsening dyspnea; timely cervical, thoracic CT and bronchoscopy can provide an accurate diagnosis. Surgical radical resection is the only way to cure all benign tracheal tumors such as lipoma.
Current Controversies in Large-Vessel Inflammatory Vasculitis and Thoracic Aortic Aneurysm Disease
Authors: Harky Amer , Fok Matthew , Howard Callum , Bashir Mohamad
Published: June 2019

Large-vessel vasculitis encompasses the spectrum of vasculitides, which pathologically cause chronic granulomatous inflammatory changes, primarily in the aorta and its major branches. These patients are at risk of developing life-threatening aortic lesions that, without recognition and prompt treatment, can cause detrimental effects. Many provocative issues surrounding large-vessel vasculitis and its surgical treatment still remain, spanning from recognition to management. In this review, we discuss the main large-vessel vasculitides, Takayasu's arteritis and giant cell arteritis. We include the key points and current controversies surrounding diagnostic imaging, timing of interventions, and patient outcomes.
Pulmonary Arterial Hypertension and Therapeutic Interventions
Authors: Ishak Gabra Nader B. , Mahmoud Omar , Ishikawa Oki , Shah Varun , Altshul Erica , Oron Maly , Mina Bushra
Published: June 2019

Pulmonary hypertension is an uncommon disease that carries a significant morbidity and mortality. Pulmonary arterial hypertension is a subtype of pulmonary hypertension that describes a group of disease entities that lead to an elevation in precapillary pulmonary artery pressure. Despite advances in the diagnosis and treatment of pulmonary arterial hypertension, it remains a difficult disease to recognize and manage. In this review article, we will discuss the definition and diagnosis of pulmonary arterial hypertension. Additionally, we will discuss the ever-expanding management options, their mechanisms and strategies, including combination therapy and the most recent advances and future directions.
Orthopaedic Surgeons and Smartphones
Authors: Ahmed Ahmed M. , Khalifa Ahmed A.
Published: June 2019

Phone technology has witnessed revolutionary advancement in the form of smartphones. Health care professionals, especially orthopaedic surgeons, have been able to make the best use of such remarkable devices. Surveys conducted over years in many different countries have shown how often orthopaedic personnel use smartphone apps for both work and education. Moreover, phone companies have provided surgeons with many useful apps that can be used in the operating theater and emergency room as well. However, there are some concerns regarding the validity of information available in the applications.
Development of two-dimensional piezoelectric laser scanner with large steering angle and fast response characteristics
Authors: Kim Ho-Sang , Lee Dae-Hee , Hur Deog Jae , Lee Dong-Chan
Published: June 2019

We describe a two-dimensional piezoelectric laser scanner designed and tested to obtain a large steering angle of 1° and fast response characteristics of 200 Hz. To overcome the relatively small expansion capability of piezoelectric actuators, the displacement amplification mechanisms with two levers in series are employed to magnify the end tip of the lever which is connected to a 0.5-in. glass mirror. For fast response characteristics, the natural frequencies of the hinge mechanisms were calculated by using the finite element analysis technique. In order to evaluate the performance of the proposed scanner, the hinge mechanism has been manufactured of titanium alloy and the natural frequencies of the hinge mechanism have been measured by sine sweep test. Also, the actual machining test on the burning paper has been done by using a high power laser, and it is shown that the proposed laser scanner is capable of steering the laser beam 1° with a frequency of 200 Hz.
Tuning of energy dispersion properties in InAlAs digital alloys
Authors: Zheng J. , Tan Y. , Yuan Y. , Ghosh A. W. , Campbell J. C.
Published: June 2019

InAlAs digital alloy avalanche photodiodes (APDs) exhibit lower noise than their random alloy counterparts. The electronic dispersion properties of digital alloy materials are unique, creating minigaps in their valence band structure. In this paper, we use computational models with environment-dependent tight-binding parameters to calculate the electronic dispersion properties of InAlAs digital alloys with various stacking directions, stacking modes, and periods, which can provide guidance for optimizing the structure of InAlAs digital alloy APDs.
Towards density functional approximations from coupled cluster correlation energy densities
Authors: Margraf Johannes T. , Kunkel Christian , Reuter Karsten
Published: June 2019

(Semi)local density functional approximations (DFAs) are the workhorse electronic structure methods in condensed matter theory and surface science. The correlation energy density ϵc(r) (a spatial function that yields the correlation energy Ec upon integration) is central to defining such DFAs. Unlike Ec, ϵc(r) is not uniquely defined, however. Indeed, there are infinitely many functions that integrate to the correct Ec for a given electron density ρ. The challenge for constructing useful DFAs is thus to find a suitable connection between ϵc(r) and ρ. Herein, we present a new such approach by deriving ϵc(r) directly from the coupled-cluster (CC) energy expression. The corresponding energy densities are analyzed for prototypical two-electron systems. As a proof-of-principle, we construct a semilocal functional to approximate the numerical CC correlation energy densities. Importantly, the energy densities are not simply used as reference data but guide the choice of the functional form, leading to a remarkably simple and accurate correlation functional for the helium isoelectronic series. While the resulting functional is not transferable to many-electron systems (due to a lack of same-spin correlation), these results underscore the potential of the presented approach.
A physically extended Lorenz system
Authors: Moon Sungju , Seo Jaemyeong Mango , Han Beom-Soon , Park Junho , Baik Jong-Jin
Published: June 2019

The Lorenz system is a simplified model of Rayleigh-Bénard convection, a thermally driven fluid convection between two parallel plates. Two additional physical ingredients are considered in the governing equations, namely, rotation of the model frame and the presence of a density-affecting scalar in the fluid, in order to derive a six-dimensional nonlinear ordinary differential equation system. Since the new system is an extension of the original three-dimensional Lorenz system, the behavior of the new system is compared with that of the old system. Clear shifts of notable bifurcation points in the thermal Rayleigh parameter space are seen in association with the extension of the Lorenz system, and the range of thermal Rayleigh parameters within which chaotic, periodic, and intermittent solutions appear gets elongated under a greater influence of the newly introduced parameters. When considered separately, the effects of scalar and rotation manifest differently in the numerical solutions; while an increase in the rotational parameter sharply neutralizes chaos and instability, an increase in a scalar-related parameter leads to the rise of a new type of chaotic attractor. The new six-dimensional system is found to self-synchronize, and surprisingly, the transfer of solutions to only one of the variables is needed for self-synchronization to occur.
Water’s two-critical-point scenario in the Ising paradigm
Authors: Cerdeiriña Claudio A. , Troncoso Jacobo , González-Salgado Diego , Debenedetti Pablo G. , Stanley H. Eugene
Published: June 2019

We present a spin-1, three-state Ising model for the unusual thermodynamics of fluid water. Thus, besides vacant cells, we consider singly occupied cells with two accessible volumes in such a way that the local structures of low density, energy, and entropy associated with water’s low-temperature “icelike” order are characterized. The model has two order parameters that drive two phase transitions akin to the standard gas-liquid transition and water’s hypothesized liquid-liquid transition. Its mean-field equation of state enables a satisfactory description of results from experiments and simulations for the ST2 and TIP4P/2005 force fields, from the phase diagram, the density maximum, or the deeply “stretched” states to the behavior of thermodynamic response functions at low temperatures at which water exists as a supercooled liquid. It is concluded that the model may be regarded as a most basic prototype of the so-called “two-critical-point scenario.”
Charge collection efficiency in photoconductive detectors under small to large signals
Authors: Ramaswami Kieran , Johanson Robert , Kasap Safa
Published: June 2019

Hecht collection efficiency η0 and its formulations for exponential absorption have been widely used in modeling charge collection efficiency in photoconductive detectors. The basic assumption of the Hecht formulation is that the electric field in the device is uniform, i.e., the photoinjected carriers do not perturb the field. Here, we have used Monte Carlo simulations to model the initial injection of electron and hole pairs and their subsequent transport and trapping in the presence of an electric field, which is calculated from the Poisson equation. Each injected carrier is tracked as it moves in the semiconductor until it is either trapped or reaches the collection electrode. Trapped carriers do not contribute to the photocurrent but continue to contribute to the field through the Poisson equation. The instantaneous photocurrent iph(t) is calculated from the drift of the free carriers through the Shockley–Ramo theorem. iph(t) is integrated over the duration of the photocurrent to calculate the total collected charge and hence the collection efficiency ηr. ηr has been calculated as a function of the charge injection ratio r, the electron and hole ranges (drift mobility and lifetime products, μτ), mean photoinjection depth δ, and drift mobility ratio b. The deviation of the collection efficiency ηr from the uniform field case η0 can be as much as 30% smaller than the small signal model prediction. However, for a wide range of electron and hole schubwegs and photoinjection ratios, typical errors remained less than 10% at full injection, the worst case. The present study provides partial justification to the wide-spread use of the uniform-field collection efficiency η0 formula in various applications, even under high injection conditions.
Ferrimagnetic resonance field sensors for particle accelerators
Authors: Beaumont Anthony , Buzio Marco , Boero Giovanni
Published: June 2019

We report on two ferrimagnetic resonance (FMR) sensors for absolute dynamic magnetic field measurements at 36 and 100 mT. The sensors are designed to mark precisely and reproducibly the moment when a time-transient magnetic field attains a specific value. The trigger from the sensor can then be used for real-time magnetic field measurement systems, called “B-trains,” which are in operation at several large synchrotron installations including five of CERN’s particle accelerators. We discuss in detail the design, the operation, and the performance of the FMR sensors based on two different types of printed circuit board (PCB) resonator structures.
Optical reconfiguration of surface relief gratings on supramolecular polymer films using grating translation and superposition
Authors: Krüger J. , Bolle N. , Calvelo T. , Bergmann S. , Abourahma H. , McGee D. J.
Published: June 2019

We demonstrate the optical erasure and amplification of surface relief gratings written on supramolecular azobenzene-polymer films. The reversible photomechanical response of azobenzene-polymer films enables surface reconfiguration through grating superposition, which is implemented through mechanical film translation and exposure in a laser interference pattern. Sinusoidal surface relief gratings could be photoerased and regenerated using laser exposures with interference patterns shifted by half a period. Gratings could also be amplified and their surface coverage extended through multiple translations and exposures at integer-period steps. We report the fabrication of a 2.0×2.0 mm2 surface grating of amplitude 697 nm from an initial grating of 78 nm amplitude through raster scanning and reexposing using a step translation equal to 10 fringes.
Hyperchaos and multistability in the model of two interacting microbubble contrast agents
Authors: Garashchuk Ivan R. , Sinelshchikov Dmitry I. , Kazakov Alexey O. , Kudryashov Nikolay A.
Published: June 2019

We study nonlinear dynamics of two coupled contrast agents that are micrometer size gas bubbles encapsulated into a viscoelastic shell. Such bubbles are used for enhancing ultrasound visualization of blood flow and have other promising applications like targeted drug delivery and noninvasive therapy. Here, we consider a model of two such bubbles interacting via the Bjerknes force and exposed to an external ultrasound field. We demonstrate that in this five-dimensional nonlinear dynamical system, various types of complex dynamics can occur, namely, we observe periodic, quasiperiodic, chaotic, and hypechaotic oscillations of bubbles. We study the bifurcation scenarios leading to the onset of both chaotic and hyperchaotic oscillations. We show that chaotic attractors in the considered system can appear via either the Feigenbaum cascade of period-doubling bifurcations or the Afraimovich–Shilnikov scenario of torus destruction. For the onset of hyperchaotic dynamics, we propose a new bifurcation scenario, which is based on the appearance of a homoclinic chaotic attractor containing a saddle-focus periodic orbit with its two-dimensional unstable manifold. Finally, we demonstrate that the dynamics of two bubbles can be essentially multistable, i.e., various combinations of the coexistence of the above mentioned attractors are possible in this model. These cases include the coexistence of a hyperchaotic regime with an attractor of any other remaining type. Thus, the model of two coupled gas bubbles provides a new example of physically relevant system with multistable hyperchaos.
Embedded atom method potentials for La-Al-Ni ternary alloy
Authors: Lei Yawei , Li Dongdong , Zhou Rulong , Zhang Bo
Published: June 2019

Based on a series of the first-principles and experimental data, a new interatomic potential for the La-Al-Ni ternary system has been developed in the framework of an embedded-atom model using a force matching technique. With the optimized potential, the ground states of various elemental phases of La, Al, Ni, and La-Al-Ni intermetallic compounds are accurately reproduced. Also, the liquid dynamic behavior and glass forming ability of the La-Al-Ni system are validated, and the simulation results show great agreement with those calculated by ab initio molecular dynamic and related experimental data, indicating the reasonability and availability of our developed embedded-atom-method potential.
Electronic structures and binding motifs of sodium polysulfide clusters NaSn− (n = 5–9): A joint negative ion photoelectron spectroscopy and computational investigation
Authors: Li Zhipeng , Hu Zhubin , Jiang Yanrong , Yuan Qinqin , Sun Haitao , Wang Xue-Bin , Sun Zhenrong
Published: June 2019

We report a joint experimental and computational study on the electronic and geometric structures of a series of NaSn− (n = 5–9) clusters. Cryogenic, size-selective, negative ion photoelectron spectroscopy was employed to obtain their photoelectron spectra, in which distinctive spectral features with electron binding energy (EBE) up to 6.4 eV are unraveled. The EBE of the first peak in each spectrum for NaSn− (n = 5–9), assigned to the transition from the ground state of the anion to the ground state of each neutral radical, was observed to increase with cluster size. The vertical detachment energies (VDEs), measured from the first peak maximum, are 3.43 ± 0.02, 3.57 ± 0.02, 3.82 ± 0.03, 3.86 ± 0.02, and 4.00 ± 0.02 eV, and the adiabatic detachment energies (ADEs), determined from the onset of the first peak, are 3.27 ± 0.05, 3.44 ± 0.05, 3.65 ± 0.05, 3.75 ± 0.05, and 3.93 ± 0.05 eV, for n = 5–9, respectively. A number of low-lying isomers of the anions were screened and identified with density functional theory calculations, showing a structural preference of a chainlike polysulfide moiety electrostatically interacting with a sodium cation for all of the clusters. The CCSD(T)/aug-cc-pVTZ calculated VDEs and ADEs are in excellent agreement with the experimental results, confirming the identified isomers. Further analyses based on excited-state transitions, molecular orbitals, and natural population charges were performed, to assign and reveal the nature of all observed spectral bands. These computational results suggest that the electron detachment process and observed excitations are mainly derived from the polysulfide chain within each NaSn− cluster. This work provides a fundamental understanding of the intrinsic molecular properties of sodium polysulfide systems, which widely exist in life science and sodium-sulfur cells.
Calculation of phase diagrams in the multithermal-multibaric ensemble
Authors: Piaggi Pablo M. , Parrinello Michele
Published: June 2019

From the Ising model and the Lennard-Jones fluid to water and the iron-carbon system, phase diagrams are an indispensable tool to understand phase equilibria. Despite the effort of the simulation community, the calculation of a large portion of a phase diagram using computer simulation is still today a significant challenge. Here, we propose a method to calculate phase diagrams involving liquid and solid phases by the reversible transformation of the liquid and the solid. To this end, we introduce an order parameter that breaks the rotational symmetry and we leverage our recently introduced method to sample the multithermal-multibaric ensemble. In this way, in a single molecular dynamics simulation, we are able to compute the liquid-solid coexistence line for entire regions of the temperature and pressure phase diagram. We apply our approach to the bcc-liquid phase diagram of sodium and the fcc-bcc-liquid phase diagram of aluminum.
Vacancy complexes in nonequilibrium germanium-tin semiconductors
Authors: Assali S. , Elsayed M. , Nicolas J. , Liedke M. O. , Wagner A. , Butterling M. , Krause-Rehberg R. , Moutanabbir O.
Published: June 2019

Depth-profiled pulsed low-energy positron annihilation lifetime spectroscopy and Doppler broadening spectroscopy were combined to identify vacancy-related complexes and probe their evolution as a function of Sn content in GeSn epitaxial layers. Regardless of the Sn content in the 6.5–13.0 at. % range, all GeSn samples showed the same depth-dependent increase in the positron annihilation line broadening parameters, relative to that of epitaxial and bulk Ge references, thus confirming the formation of open volume defects during growth. The measured average positron lifetimes were found to be the highest (380–395 ps) in the region near the surface and monotonically decrease across the analyzed thickness but remain above 350 ps. All GeSn layers exhibit average lifetimes that are 20–160 ps higher than those recorded for the Ge reference. Surprisingly, these lifetimes were found to decrease as the Sn content increases in GeSn layers. These measurements indicate that divacancies are the dominant defect in the as-grown GeSn layers. However, their corresponding lifetime was found to be shorter than in epitaxial Ge, thus suggesting that the presence of Sn may alter the structure of divacancies. Additionally, GeSn layers were also found to contain a small fraction of vacancy clusters, which become less important as the Sn concentration increases. The interaction and possible pairing between Sn and vacancies have been proposed to explain the reduced formation of larger vacancy clusters in GeSn when the Sn content increases.
New insights into the physics of inertial microfluidics in curved microchannels. II. Adding an additive rule to understand complex cross-sections
Authors: Rafeie Mehdi , Hosseinzadeh Shahin , Huang Jingrui , Mihandoust Asma , Warkiani Majid Ebrahimi , Taylor Robert A.
Published: June 2019

Curved microchannels allow controllable microparticle focusing, but a full understanding of particle behavior has been limited—even for simple rectangular and trapezoidal shapes. At present, most microfluidic particle separation literature is dedicated to adding “internal” complexity (via sheath flow or obstructions) to relatively simple cross-sectional channel shapes. We propose that, with sufficient understanding of particle behavior, an equally viable pathway for microparticle focusing could utilize complex “external” cross-sectional shapes. By investigating three novel, complex spiral microchannels, we have found that it is possible to passively focus (6, 10, and 13 μm) microparticles in the middle of a convex channel. Also, we found that in concave and jagged channel designs, it is possible to create multiple, tight focusing bands. In addition to these performance benefits, we report an “additive rule” herein, which states that complex channels can be considered as multiple, independent, simple cross-sectional shapes. We show with experimental and numerical analysis that this new additive rule can accurately predict particle behavior in complex cross-sectional shaped channels and that it can help to extract general inertial focusing tendencies for suspended particles in curved channels. Overall, this work provides simple, yet reliable, guidelines for the design of advanced curved microchannel cross sections.
First-Principles study of two dimensional transition metal phthalocyanine-based metal-organic frameworks in kagome lattice
Authors: Chen Hao-qi , Shan Huan , Zhao Ai-di , Li Bin
Published: June 2019

Transition metal phthalocyanines (TMPc) and relevant derivatives can act as pervasive molecules for their electronic, magnetic, and optical applications. Numerous researches based on TMPc are carried out, attempting to synthesize novel two-dimensional (2D) metal-organic frameworks. Recently, some 2D poly-TMPc frameworks including FePc [J. Am. Chem. Soc. 133, 1203 (2011)], CoPc [Chem. Commun. 51, 2836 (2015)], and Ni-NiPc [J. Mater. Chem. A 6, 1188 (2018)] frameworks have been successfully synthesized experimentally. Meanwhile, potential applications in catalysis, gas storage, and spintronics were predicted by theoretical studies. Here, we propose a new kind of 2D poly-TMPc frameworks with kagome lattice (denoted as kag-TMPc) and systematically investigate their electronic and magnetic properties by employing first-principles calculations. We have demonstrated that the 2D kag-MnPc framework displays quite stable ferromagnetic ordering with Curie temperature about 125 K as indicated by Monte Carlo simulations based on Heisenberg model and prefers out-of-plane easy-magnetization axis. The 2D kag-CrPc framework is an ideal candidate for S=2 kagome antiferromagnet with RT3 magnetic order. Particularly, the investigations on optical absorption suggest that when the TMPc molecules are self-assembled into 2D kag-TMPc frameworks, their absorption wave bands are broadened, especially in visible region.
Influence of neighboring layers on interfacial energy of adjacent layers
Authors: Li Lei-lei , Feng Shuo
Published: June 2019

The binding energy and generalized stacking-fault energy (GSFE) are two critical interface properties of two dimensional layered materials, and it is still unclear how neighboring layers affect the interface energy of adjacent layers. Here, we investigate the effect of neighboring layers by comparing the differences of binding energy and GSFE between trilayer heterostructures (graphene/graphene/graphene, graphene/graphene/boron nitride, boron nitride/graphene/boron nitride) and bilayer heterostructures (graphene/graphene, graphene/boron nitride) using density functional theory. The binding energy of the adjacent layers changes from −2.3% to 22.55% due to the effect of neighboring layer, with a very small change of the interlayer distance. Neighboring layers also make a change from −2% to 10% change the GSFE, depending on the property of the interface between adjacent layers. In addition, a new simple expression is proven to describe the GSFE landscape of graphene-like structure with high accuracy.
Femtosecond time-resolved spectroscopic photoemission electron microscopy for probing ultrafast carrier dynamics in heterojunctions
Authors: Li Bo-han , Zhang Guan-hua , Liang Yu , Hao Qun-qing , Sun Ju-long , Zhou Chuan-yao , Tao You-tian , Yang Xue-ming , Ren Ze-feng
Published: June 2019

The fast developing semiconductor industry is pushing to shrink and speed up transistors. This trend requires us to understand carrier dynamics in semiconductor heterojunctions with both high spatial and temporal resolutions. Recently, we have successfully set up a time-resolved photoemission electron microscopy (TR-PEEM), which integrates the spectroscopic technique to measure electron densities at specific energy levels in space. This instrument provides us an unprecedented access to the evolution of electrons in terms of spatial location, time resolution, and energy, representing a new type of 4D spectro-microscopy. Here in this work, we present measurements of semiconductor performance with a time resolution of 184 fs, electron kinetic energy resolution of 150 meV, and spatial resolution of about 150 nm or better. We obtained time-resolved micro-area photoelectron spectra and energy-resolved TR-PEEM images on the Pb island on Si(111). These experimental results suggest that this instrument has the potential to be a powerful tool for investigating the carrier dynamics in various heterojunctions, which will deepen our understanding of semiconductor properties in the submicron/nanometer spatial scales and ultrafast time scales.
Dark color ZnO quasi-one-dimensional nanostructures grown by hydrothermal method and modulation of their optical properties
Authors: Chen Hao , Dong Na , Wang Kai , Yao Yi , Xu Faqiang
Published: June 2019

Zinc oxide has a large energy gap and thus it has potential application in the field of solar cells by tuning the absorption of sunlight. In order to enhance its absorption of sunlight, dark color zinc oxides have been prepared by traditional hydrothermal method directly using a zinc foil as both source and substrate. We found that we could tune the optical properties of ZnO samples by changing the temperature. In particular, increasing temperature could significantly reduce the reflectivity of solar energy in the visible range. We speculate that the phenomenon is relevant to the sharp cone morphology of the ZnO nanorods grown on the surface of Zn foils, which furthermore enhance refraction and reflection of light in the nanorods. The capacity to improve the light absorption of ZnO may have a bright application in raising the efficiency of solar cells.