bluuebunny/crossref_metadata_2025 huggingface dataset:
Long-term Follow-up and Safety of Patients after an Upfront Therapy with Letrozole for Early Breast Cancer in Routine Clinical Care – The PreFace Study
Authors: Hein Alexander , Fasching Peter A. , Hack Carolin C. , Maass Nicolai , Aktas Bahriye , Kümmel Sherko , Thomssen Christoph , Wolf Christopher , Kolberg Hans-Christian , Brucker Cosima , Janni Wolfgang , Dall Peter , Schneeweiss Andreas , Marme Frederik , Ruebner Matthias , Theuser Anna-Katharin , Hofmann Nadine M. , Böhm Sybille , Almstedt Katrin , Kellner Sara , Nabieva Naiba , Gass Paul , Sütterlin Marc W. , Lück Hans-Joachim , Schmatloch Sabine , Kalder Matthias , Uleer Christoph , Juhasz-Böss Ingolf , Hanf Volker , Jackisch Christian , Müller Volkmar , Rack Brigitte , Belleville Erik , Wallwiener Diethelm , Rody Achim , Rauh Claudia , Bayer Christian M. , Uhrig Sabrina , Goossens Chloë , Huebner Hanna , Brucker Sara Y. , Häberle Lothar , Fehm Tanja N.
Published: May 2024

Adjuvant treatment of patients with early-stage breast cancer (BC) should include an aromatase inhibitor (AI). Especially patients with a high recurrence risk might benefit from an upfront therapy with an AI for a minimum of five years. Nevertheless, not much is known about the patient selection for this population in clinical practice. Therefore, this study analyzed the prognosis and patient characteristics of postmenopausal patients selected for a five-year upfront letrozole therapy.

From 2009 to 2011, 3529 patients were enrolled into the adjuvant phase IV PreFace clinical trial (NCT01908556). Postmenopausal hormone receptor-positive BC patients, for whom an upfront five-year therapy with letrozole (2.5 mg/day) was indicated, were eligible. Disease-free survival (DFS), overall survival (OS) and safety in relation to patient and tumor characteristics were assessed.

3297 patients started letrozole therapy. The majority of patients (n = 1639, 57%) completed the five-year treatment. 34.5% of patients continued with endocrine therapy after the mandated five-year endocrine treatment. Five-year DFS rates were 89% (95% CI: 88–90%) and five-year OS rates were 95% (95% CI: 94–96%). In subgroup analyses, DFS rates were 83%, 84% and 78% for patients with node-positive disease, G3 tumor grading, and pT3 tumors respectively. The main adverse events (any grade) were pain and hot flushes (66.8% and 18.3% of patients).

The risk profile of postmenopausal BC patients selected for a five-year upfront letrozole therapy showed a moderate recurrence and death risk. However, in subgroups with unfavorable risk factors, prognosis warrants an improvement, which might be achieved with novel targeted therapies.
Secondary Histiocytic Sarcoma in a Pre-B-Acute Lymphoblastic Leukemia
Authors: Ramakrishnan Sharanya , Radhakrishnan Vivek , Dhabe Aaishwarya , Parihar Mayur , Zameer Lateef , Arora Neeraj , Nair Reena
Published: May 2024

Histiocytic sarcoma (HS) is a rare malignancy with grave prognosis. Adult acute lymphoblastic leukemia (ALL) patients developing HS as a secondary malignancy reported in the literature is even rarer. Through our case report, we aim to describe an adult pre-B-ALL patient who subsequently developed extensive HS while on maintenance therapy. We present the course of the disease, the management, and the resultant outcome. Active reporting of the course and management of secondary HS in adult ALL patients need to be emphasized to gain better insight into the presentation and the course of the disease, incidence as well as molecular pathology, especially given the relative silence of the literature in this regard.
Modeling the audience’s perception of security in media discourse
Authors: Hu Chajuan
Published: May 2024

Combining the concepts of securitization with a discourse analytic approach, the study presents an attempt to investigate how the audience’s perception toward an unconventional security issue has been shaped in media context. As a case study, this paper delves into the portrayal of the Confucius Institute in the U.S. media discourse. By analyzing the coverage of the Confucius Institute in The New York Times and The Wall Street Journal from 2004 to 2022, it aims to unpack the narratives and representations surrounding this institution. With a particular focus on how the use of language shapes the audience’s perception and subsequently influences their cognition in the context of the securitization of Confucius Institutes, a select sample of texts from the corpus was collected for coded qualitative analysis to allow for a deeper understanding of how the media constructs and disseminates information about the Confucius Institute. The findings turn out that American media actors deliver a bottom-up securitizing move by interacting with socio-political value positions on Confucius Institutes in the United States, grounding a cognitive construction of security threat into shaping public emotive perceptual experience with dialogically patterned linguistic configurations.
Similar but yet different: individual cognitive traits and family contingencies as antecedents of intrapreneurship and self-employment
Authors: Huang Yongchun , Wu Shangshuo , Chen Chengmeng , Zou Chen , Pan Anqi
Published: May 2024

Entrepreneurship is of great significance to individuals, families and society. Recently, intrapreneurship, i.e., business ventures within established organisations, has also attracted widespread interest among individuals and organisations. However, we still know little about how individuals make decisions when they face diverse types of entrepreneurial activities. Based on theories of entrepreneurial action and conservation of resources and the literature on family embeddedness, this paper proposes an integrated framework for entrepreneurial choice—including intrapreneurship, self-employment and non-entrepreneurship, and examines the roles of socio-cognitive traits and family contingency factors in the entrepreneurial choice process. By using secondary and survey data, the empirical results show that (a) entrepreneurial alertness (EA) and self-efficacy (ESE) both positively affect individuals’ choice towards intrapreneurship and self-employment, with a stronger effect on the latter; (b) the interaction between EA and ESE has a negative effect on intrapreneurship but a positive effect on self-employment; (c) family-to-work conflict weakens the aforementioned interactive effect on both intrapreneurship and self-employment, whereas work-to-family conflict strengthens its effect on self-employment; (d) household income strengthens the interactive effect on both intrapreneurship and self-employment. Overall, these findings contribute to a nuanced understanding of the relationship among individual cognitive traits, family contingencies and entrepreneurial choice. The theoretical and practical implications are discussed.
Pricing, assembly rate optimizations and coordination for prefabricated construction supply chain with government subsidies
Authors: Jiang Wen , Pu Linqing , Qiu Manqi , Zhang Lin
Published: May 2024

Prefabricated construction, a sustainable construction method, has become the inevitable trend for the future development of the construction industry. The subsidy policies for prefabricated construction enterprises can influence their strategies to promote the development of prefabricated construction. The paper considers a two-echelon prefabricated construction supply chain consisting of a manufacturer and an assembler, aiming to investigate pricing and the assembly rate strategies and coordination under different subsidy objects. The findings demonstrate that subsidy policies can increase the assembly rate. When the government subsidizes the manufacturer, the wholesale price decreases with the subsidy rate, while subsidizing the assembler, the wholesale price does not change. The impacts of subsidy policies on the retail price depend on price sensitivity and the consumer preference for the prefabricated construction market. When the subsidy rates are equivalent, the profit of supply chain with subsidizing the assembler is greater than that with subsidizing the manufacturer. Finally, the paper proposes the revenue-cost sharing contract to coordinate prefabricated construction supply chain with government subsidies. A numerical study is carried out to verify conclusions, and illustrates that a certain range of subsidy affects positively prefabricated construction enterprises by adjusting the retail price and increasing the assembly rate.
Phase change-related thermal property characterization and enhancement in carbon-based organic phase change composites
Authors: Li Mingxin , Wang Xuanjie , Shen Junhua , Zhao Dong , Lian Jie
Published: May 2024

By utilizing the significant amount of energy absorbed and released during their phase transitions, phase change materials (PCMs) can capture and store thermal energy to fill gaps between supply and demand. Due to their many favorable properties, organic PCMs have gained attention in a wide range of applications. Nevertheless, their inherent low thermal conductivity has limited the direct use of organic PCMs in thermal energy storage (TES). Extensive research has been conducted on enhancing organic PCM thermal conductivity by incorporating high thermal conductivity materials. Owing to their high thermal conductivity and low density, carbon-based materials have been extensively used for thermal conductivity enhancement in phase change composites (PCCs). Carbon-based organic PCCs, which incorporate highly thermally conductive carbon allotropes and their direct chemical derivatives with organic PCMs, are a group of diverse PCCs with highly promising potential for TES applications. Adequate latent heat and shape stability performances are crucial to the success of the applicational performances of these PCCs. Much empirical research has pushed efforts to enhance these phase change properties, yet a logical understanding of these enhancement efforts based on the thermodynamics and intermolecular interactions of carbon-based organic PCCs has been elusive. In particular, the effect of characterization methods on the evaluation of phase change properties has been largely understudied. This review strives to provide novel physical and chemical insights into latent heat and shape stabilization evaluation processes and enhancement efforts in carbon-based organic PCCs through a detailed review and analysis of recent literature. The review provides an unprecedented comprehension of newly developed PCCs that challenge the traditional understanding that the latent heat of PCCs cannot exceed that of its base PCM. Efforts on phase change property enhancement driven by these new insights have the potential for carbon-based organic PCCs to succeed in a variety of TES applications, including solar-thermal harvesting, thermal management of batteries and electronics, thermoregulating textiles, and infrared stealth and infrared responsive materials.
Ca2+-sensor ALG-2 engages ESCRTs to enhance lysosomal membrane resilience to osmotic stress
Authors: Chen Wei , Motsinger Madeline M. , Li Jiaqian , Bohannon Kevin P. , Hanson Phyllis I.
Published: May 2024

Lysosomes are central players in cellular catabolism, signaling, and metabolic regulation. Cellular and environmental stresses that damage lysosomal membranes can compromise their function and release toxic content into the cytoplasm. Here, we examine how cells respond to osmotic stress within lysosomes. Using sensitive assays of lysosomal leakage and rupture, we examine acute effects of the osmotic disruptant glycyl-L-phenylalanine 2-naphthylamide (GPN). Our findings reveal that low concentrations of GPN rupture a small fraction of lysosomes, but surprisingly trigger Ca2+release from nearly all. Chelating cytoplasmic Ca2+makes lysosomes more sensitive to GPN-induced rupture, suggesting a role for Ca2+in lysosomal membrane resilience. GPN-elicited Ca2+release causes the Ca2+-sensor Apoptosis Linked Gene-2 (ALG-2), along with Endosomal Sorting Complex Required for Transport (ESCRT) proteins it interacts with, to redistribute onto lysosomes. Functionally, ALG-2, but not its ESCRT binding-disabled ΔGF122splice variant, increases lysosomal resilience to osmotic stress. Importantly, elevating juxta-lysosomal Ca2+without membrane damage by activating TRPML1 also recruits ALG-2 and ESCRTs, protecting lysosomes from subsequent osmotic rupture. These findings reveal that Ca2+, through ALG-2, helps bring ESCRTs to lysosomes to enhance their resilience and maintain organelle integrity in the face of osmotic stress.
Effects of listeners’ dialectal variation on comprehensibility and accentedness judgements of second language
speech
Authors: Ghaffarvand-Mokari Payam
Published: May 2024

This study investigated the impact of listeners’ dialectal variations within the same L1 on perceptions of L2
speech comprehensibility and accentedness. Thirty untrained British and American English-L1 raters assessed recorded L2 speech
samples from 29 Finnish learners of English and provided scalar judgments for their comprehensibility and accentedness. Four
linguistically trained graduate students evaluated the samples for segmental accuracy, speech rate, word stress and intonation.
Results of linear mixed models indicated no significant effect of raters’ L1 variety on global comprehensibility and accentedness
ratings. While American and British raters relied on same pronunciation features in their comprehensibility judgments, they placed
different levels of importance on pronunciation features when making accentedness judgments. Particularly, both groups primarily
exhibited sensitivity towards segmental errors in their assessments of accentedness, whereas American raters demonstrated an
additional sensitivity to intonation. The findings underscore the complexity of accent perception based on the L1 variety of
listeners.
One-day listen-and-repeat training of a non-native vowel duration contrast for speakers of Namibian
languages
Authors: Saloranta Antti , Haapanen Katja , Peltola Kimmo U. , Tamminen Henna , Alku Paavo , Uwu-khaeb Lannie , Peltola Maija S.
Published: May 2024

Listen-and-repeat training has previously been successfully used to train the perception and production of
non-native vowel quality and duration contrasts. This study used a one-day listen-and-repeat training paradigm for the production
of a non-native vowel duration contrast, /tite – tiːte/ with no feedback or other instructions. Learning results were assessed by
acoustic analysis of the produced durations, and identification of the productions by listeners with quantity contrasts in their
native Finnish language. Training participants were 18 Namibian speakers of various Bantu and Khoe languages. The results showed
that the majority of the speakers did not produce a consistent acoustic duration contrast between the target words. In the
identification task, the listeners’ performance was at essentially chance level for almost all of the speakers. The results are
discussed in terms of earlier results using the same stimuli, training design and language background.
Dependence temperature on effective mass and susceptibility in quantum well-wires
Authors: Van Tan Le
Published: May 2024

In this study, we investigated the simulation impact of carrier density and temperature on properties such as susceptibility and effective mass of electrons in GaAs/Al
x
Ga1−x
As quantum-well wires, involving the treatment of Coulomb interaction and the interaction between electrons and holes with longitudinal optical phonons (LO-phonon) on an equal basis. The susceptibility and effective mass were calculated and compared with the results when no phonon coupling was considered. Furthermore, the key findings were compared with results from the sum-rule version of the Singwi-Tosi-Land-Sj

o

̈

lander (STLS) theory, mean-spherical approximation (MSA) theory, and there is a high level of concordance between this formula and experimental values obtained by other researchers. Our results reveal that carrier concentration and temperature significantly affect susceptibility and effective mass of the quantum well-wires in both cases, with LO-phonon contributions. These results contribute to illuminating how Coulomb interactions and exchange-correlation energies influence the susceptibility and effective mass of GaAs/Al
x
Ga1−x
As across a broad range of temperature and carrier density conditions.
Comprehensive investigation into the influence of oxygen vacancies on the ferroelectric properties of spin coated bismuth ferrite thin films
Authors: N V Srihari , Bayari Sumanth , Kumar M V Santhosh , Padaki Mahesh , K K Nagaraja
Published: May 2024

Bismuth ferrite (BFO) is a prime candidate for room-temperature magnetoelectric coupling and multiferroic applications. The rhombohedral R3c phase of BFO is the source of many properties, but the phase purity and oxygen vacancies are still the biggest obstacles to its real-world application. Considering these facts, the present work investigates the effects of oxygen vacancies on the functional properties through manipulation of drying temperatures of spin-cast films, especially at temperatures around 280 °C, where both the secondary phase and oxygen vacancies are prevalent. One of the biggest sources of oxygen vacancy is bismuth volatilisation, and our work deals with the situation head-on, uncovering the effect of bismuth volatilisation on functional properties. The structural properties were studied using x-ray diffraction (XRD), and deeper insights into the surface topography of the samples were obtained using AFM imaging. The electrical and dielectric characteristics help distinguish and analyse the samples in terms of the presence of resistive switching. PUND studies were performed to determine the ferroelectric properties of the samples. A fifty percent reduction in the oxygen vacancies in the presence of secondary phases was observed when compared with the phase-pure sample, as shown by the XPS analysis. Deeper insights were provided into the valence band spectra by first-principles studies. This work shows that phase purity may not be the singular condition for enhancing functional properties, and fine-tuning the presence of secondary phases and oxygen vacancies may be the way forward. The ferroelectric polarisation in one of the samples exhibits a notably higher value when using chemical solution deposition methods, making it a promising candidate for memory devices.
Discriminating between diabetic and non-diabetic patient’s blood serum using near-infrared Raman spectroscopy
Authors: Khan Saranjam , Rehan Imran , Ullah Rahat
Published: May 2024

The current study demonstrates the utilization of Raman spectroscopy, employing a laser system emitting @ 785 nm, and multivariate analysis for the accurate assessment of diabetes (glucose) in human blood sera. Raman spectra of sera samples collected from 40 patients of both genders of different age groups were acquired in the spectral range of 600–1800 cm−1. For comparison, the Raman spectra of non-diabetic healthy individuals were also obtained in the same spectral range. Apparent variations were found in normal and pathological samples at peak positions of 700 cm−1, 750 cm−1, 879 cm−1, 950 cm−1, band at 1004 cm−1 to 1006 cm−1, 1048 cm−1, 1060 cm−1, 1082 cm−1, 1091 cm−1, 1170 cm−1, 1247 cm−1, 1330 cm−1, 1333 cm−1, 1367 cm−1, 1659 cm−1 and 1745 cm−1. These variations are most likely due to variations in the concentration of amino-acid methionine, glycosylated, tryptophan, polysaccharides, phenylalanine, glycogen, glucose, carbohydrates, carbohydrates (C–O–H), tyrosine, guanine, typical phospholipids, guanine, phospholipid, cholesterol band, and triglycerides (fatty acids) respectively. For highlighting the spectral differences between the two data sets principal component analysis was used. The observed variations in Raman peaks provide an in-depth biochemical fingerprint of the samples and can be used as a biomarker for medical diagnosis effectively at the mass level.
Collectively induced transparency and absorption in waveguide quantum electrodynamics with Bragg atom arrays
Authors: Cheng Haolei , Nie Wei
Published: May 2024

Collective quantum states, such as subradiant and superradiant states, are useful for controlling optical responses in many-body quantum systems. In this work, we study novel collective quantum phenomena in waveguide-coupled Bragg atom arrays with inhomogeneous frequencies. For atoms without free-space dissipation, collectively induced transparency is produced by destructive quantum interference between subradiant and superradiant states. In a large Bragg atom array, multi-frequency photon transparency can be obtained by considering atoms with different frequencies. Interestingly, we find collectively induced absorption (CIA) by studying the influence of free-space dissipation on photon transport. Tunable atomic frequencies nontrivially modify decay rates of subradiant states. When the decay rate of a subradiant state equals to the free-space dissipation, photon absorption can reach a limit at a certain frequency. In other words, photon absorption is enhanced with low free-space dissipation, distinct from previous photon detection schemes. We also show multi-frequency CIA by properly adjusting atomic frequencies. Our work presents a way to manipulate collective quantum states and exotic optical properties in waveguide quantum electrodynamics (QED) systems.
Aging properties of the voter model with long-range interactions
Authors: Corberi Federico , Smaldone Luca
Published: May 2024

We investigate the aging properties of the one-dimensional voter model with long-range interactions in its ordering kinetics. In this system, an agent,

S
i

=
±
1

, positioned at a lattice vertex i, copies the state of another one located at a distance r, selected randomly with a probability

P
(
r
)
∝

r

−
α

. Employing both analytical and numerical methods, we compute the two-time correlation function

G
(
r
;
t
,
s
)

(

t
⩾
s

) between the state of a variable Si
at time s and that of another one, at distance r, at time t. At time t, the memory of an agent of its former state at time s, expressed by the autocorrelation function

A
(
t
,
s
)
=
G
(
r
=
0
;
t
,
s
)

, decays algebraically for α > 1 as

[
L
(
t
)

/

L
(
s
)

]

−
λ

, where L is a time-increasing coherence length and λ is the Fisher–Huse exponent. We find λ = 1 for α > 2, and

λ
=
1

/

(
α
−
1
)

for

1
<
α
⩽
2

. For

α
⩽
1

, instead, there is an exponential decay, as in the mean field. Then, in contrast with what is known for the related Ising model, here we find that λ increases upon decreasing α. The space-dependent correlation

G
(
r
;
t
,
s
)

obeys a scaling symmetry

G
(
r
;
t
,
s
)
=
g
[
r

/

L
(
s
)
;
L
(
t
)

/

L
(
s
)
]

for α > 2. Similarly, for

1
<
α
⩽
2

, one has

G
(
r
;
t
,
s
)
=
g
[
r

/

L

(
t
)
;

L

(
t
)

/

L

(
s
)
]

, where the length

L

regulating two-time correlations now differs from the coherence length as

L

∝

L
δ

, with

δ
=
1
+
2
(
2
−
α
)

.
Study of critical deviation transfer for assembly of complex structural parts of aircraft
Authors: Huang Meng , Li Bo , Chen Xiaoyun , Zhuang Qineng , Guo Yanbing
Published: May 2024

In current assembly process of the aircraft complex structural parts, there are problems such as nonlinear, multilevel strong coupling and large uncertainty transfer relationship between assembly quality and its deviation sources. In this paper, an assembly deviation transfer method based on transfer entropy network graph is proposed to address the challenges. Firstly, the source of assembly deviation is analysed by constructing a multi-level assembly coordination network with assembly deviation detection data. Secondly, an assembly deviation propagation model is established by combining transfer entropy and complex network graph theory. This model provides insights into the topological relationship of assembly deviations and introduces causal metrics for evaluation. The effectiveness of method is demonstrated through its application in the assembly of an aircraft nose, thereby verifying its practicality and utility.
Development of flow metering for electric aircraft oil pump
Authors: Xuepeng Li , Wenlong Zhang , Yueming Cheng , Jianghong Li
Published: May 2024

In order to solve the difficulty of flow control in electric aircraft oil pump system, an electric aircraft oil pump was used as research object, with speed range of 2000rpm∼9000rpm, temperature range of 270K∼325K, pressure between the input and output of pump do not exceed 0.6MPa, and aviation 8B aircraft oil as medium. The influencing factors of aircraft oil flow were analysed, and an experimental system for researching flow metering methods was constructed. Based on the experimental data, an accurate flow metering model was established, which is significant for the metering and control of electric aircraft oil pump systems.
Modeling and evaluation of centrifugal pump performance degradation model based on stochastic process
Authors: Chen Xuan , Li Jia , Li Ping , Gao Limin , Chen Xiaolong
Published: May 2024

In order to clarify the performance degradation problem of fuel centrifugal pumps, a stochastic process-based performance degradation model modeling method is given with an aero-engine fuel centrifugal pump as the object of study, and the reliability assessment is carried out. First, the degradation modeling method based on stochastic process is given. Secondly, PumpLinx is utilized to obtain the performance degradation data of the centrifugal pump and perform data processing. Gamma and Wiener stochastic process models are given based on MATLAB. Finally, based on the centrifugal pump performance degradation data for centrifugal pump reliability assessment, and compare and analyze the advantages and disadvantages of the two modeling methods, and found that the degradation modeling method based on the Gamma process is more suitable for centrifugal pump reliability assessment.
Transient numerical investigation on thermochemical erosion of C/C nozzles in hybrid rocket motors
Authors: Jiang Xianzhu , Tian Hui , Ge Xuanhong
Published: May 2024

Nozzle erosion is a vital important issue that impacts the performance of hybrid rocket motors. Serious nozzle erosion may significantly decrease the combustion chamber pressure and thrust, which increases the difficulty in designing flight control systems. This paper aims to reveal erosion mechanism systematically. In this paper, transient numerical simulations of thermochemical erosion in hybrid rocket motors are conducted, and combustion flow and thermochemical erosion are coupled calculated. The numerical computation of combustion flow is based on the chemical reactions of propellants and regression rate model, and that of thermochemical erosion is based on the surface reactions between oxidizing species and carbon. The movement of burning surface and nozzle inner surface is simulated through dynamic mesh method. The hybrid rocket motor adopts 90% hydrogen peroxide and hydroxyl-terminated polybutadiene. Distributions of flow field parameters and fuel regression rate are given. The spatial developing process of nozzle surface is presented, and it is found that the roughness of nozzle profile increases with time. The nozzle wall temperature and wall pressure decline with time. Erosion by different species is calculated. OH and H2O make a major contribution to the nozzle thermochemical erosion, while nozzle erosion contributed by CO2 and O2 are quite low. Time-varying characteristics of the erosion rate are unveiled. At the first 1.5 s, the total erosion rate remains almost constant, and then it reduces over time.
Mathematical modeling and time-frequency characterization of aero-engine actuators
Authors: Pan P F , Li J , Guo Z B , Chen X L
Published: May 2024

The actuator is an essential part of the aero-engine control system, and its performance directly determines the efficiency of the whole system. The mathematical model of the aero-engine actuators, including electro-hydraulic servo valves, hydraulic cylinders, and actuators, is modeled and the time-frequency characteristics are analyzed using the Simulink module. Then, the system response is simulated and its time-frequency characteristics are analyzed. The simulation results show that the simulation error of the established actuator model is within the allowable range. The displacement response and the servo valve flow response fluctuate slightly near the steady state value, and the error value is only 0.857% at the maximum fluctuation value, and the system still works normally when a dynamic load is added to the system.
Distributed dynamic backup servo control for satcom-on-the-move systems
Authors: Ren Jiao , Ji Xiaoxiang , Li Jianghong , Han Lei , Wu Yafeng
Published: May 2024

This paper proposes a distributed control system for the servo control of the Satcom-On-The-Move (SOTM) systems. The servo control system is designed based on a distributed structure, which divides the control system into four sub-systems according to their functions. Each sub-system is equipped with a dedicated controller, and the controllers are connected to sensors and actuators via a bus. The control tasks of each sub-system are carried out by their respective controllers. To mitigate the impact of controller failures on the control system during running, a backup sub-system is implemented, which dynamically adjusts its function and state to ensure the normal running of the control system. An analysis of the impact of the switch to the backup sub-system on the stability of the control system under fault condition is presented. Finally, experimental analysis is conducted, and the results demonstrate the feasibility and effectiveness of the proposed design.
Study on laser ignition and combustion characteristics of micron-sized aluminum and Al-Mg alloys particles
Authors: Hou Fengting , Zhang Beichen , Feng Muyang , Liu Shuwei , Li Shipeng
Published: May 2024

In response to the problems of easy sintering and long ignition delay time of micron aluminum in the combustion of aluminum-containing propellants, choose the way to add magnesium to metal aluminum to construct an alloy system, through boiling, micro-explosions are generated during the ignition and combustion process to weaken the sintering behavior and shorten the ignition delay time of aluminum. Selecting aluminum and Al-Mg alloy powder fuel with a particle diameter of about 10 μm as the research object, a set of individual-particle fuel laser ignition and microscopic high-speed imaging experimental devices was built that can observe the whole process of ignition and combustion of micron-sized fuel. Thermal analysis was used to detect and characterize the thermal decomposition process of micron-sized aluminum and Al-Mg alloy powders; combined with the results of scanning electron microscopy, the difference in ignition performance of micron-sized individual particle aluminum and Al-Mg alloys was studied. Experiments have found that, compared with aluminum, the initial oxidation temperature of Al-Mg alloys is lower and the combustion is more complete. However, the effect of adding magnesium to aluminum is only reflected before 900 °C. The ignition and combustion images and flame propagation laws of micron-sized single-particle aluminum and Al-Mg alloys were obtained. It was found that adding magnesium shortened the ignition delay time, and the combustion produced less residual.
Analysis of landing gear walk vibration characteristics excited by aircraft anti-skid brakes
Authors: Wang Zhuangzhuang , Liu Xiaochao , Mei Haocong , Qiao Weizhi
Published: May 2024

Currently, there is not enough research on the mechanism that causes the vibration of landing gear walk when an aircraft anti-skid brake is activated. This paper aims to provide a comprehensive analysis of the characteristics of the landing gear walk and the associated research. It shows that the walk vibration is caused by a cantilever beam’s tip mass and that the study should focus on the landing gear walk’s characteristics. Firstly, according to the transverse vibration theory of cantilever beams, the transcendental equation for calculating the natural frequency of the landing gear can be obtained. After that, the influence of the structural parameters of the landing gear on each order of the natural frequency is analyzed. To ensure that the conclusions derived are applicable to all landing gear structures, the structural parameters are selected to cover both small unmanned aerial vehicles and large civil aircraft. Finally, the influence of the axial pressure of the landing gear on its inherent frequency is analyzed.
Durability analysis of large and medium-sized unmanned aerial vehicles based on load spectrum and probabilistic fracture mechanics
Authors: Xuanbao Wang , Liang Si , Jiaxing Wang , Zilong Wang , Shuo Wang , Ping Hu , Fanshun Duanmu
Published: May 2024

The analysis of unmanned aerial vehicle (UAV) durability is crucial for cost-effective repair and maintenance. Assessing the degree of damage and predicting the economic lifespan of a UAV is a critical component of its design and use. To evaluate the durability of large and medium-sized UAVs, data is gathered, and simulations are performed under real-world working conditions. The analysis includes creating a crack growth model for small cracks and determining the distribution of crack sizes, estimating the distribution of Time to Crack Initiation (TTCI), and calculating the general Equivalent Initial Flaw Size (EIFS) distribution. The results obtained from these analyses meet the UAV’s flight hour requirements and help to predict its economic life. This prediction is also beneficial for managing and maintaining the UAV’s life cycle.
Effect of U-shaped notches on nozzle performance and jet flow structures
Authors: Wu Zehuan , Wang Qimin , Wang Meili , Zhang Meihong
Published: May 2024

In nacelle design, optimization of nozzle shape is crucial for flow control. To understand the effect of nozzle shape on its aerodynamic performance and jet flow structures, the numerical experiment is performed using the dual separate flow reference (DSFR) nozzle released by the Aero Systems Engineering (ASE) FluidDyne Laboratory. A pair of U-shaped notches are made on the nozzle. The results show that the discharge coefficient and thrust angle increase with the size of the notches in all the simulated operating conditions. The notches induce a pair of streamwise vortices, which enhance turbulent mixing and decrease turbulent kinetic energy in the mixing layer.
Effects of wall transpiration on the supersonic boundary-layer oblique-type transition
Authors: Zhang Lun , Jiang Zhongzheng , Chen Weifang
Published: May 2024

The study of transpiration cooling is vital for the development of high-speed aircraft. In the current work, direct numerical simulation (DNS) is performed to investigate the impacts of wall transpiration on the boundary-layer oblique breakdown over a Mach 2 flat plate. The porous injection model is used to mimic the transpiration from the equally spaced circular pores. It has been observed from the numerical results that wall transpiration leads to the amplified growth rate of the imposed oblique mode waves, steady vortex waves, and other higher-harmonic waves. As a result, the occurrence of boundary-layer transition shifts upstream. Due to the presence of transpiration, the normal gradients of both streamwise velocity and temperature are decreased at the wall, which causes reduced skin friction and heat flux in the transpiration region. In addition, when upstream transpiration is present, reductions in skin friction and heat flux can also be observed within turbulent regions. This study provides insights into the DNS investigation on compressible boundary-layer natural transitions coupled with wall transpiration, and the results indicate that more systematic investigations addressing this problem are needed.
Study on setting method of temperature sensor in aircraft environmental control system
Authors: Zhang Xuan , Dang Xiaomin
Published: May 2024

This paper analyzes the working principle of each component of the aircraft environmental control system (ECS), takes the Boeing 737 aircraft as an example, and analyzes the distribution and role of temperature sensors in the aircraft ECS. Then, this paper presents a guideline for sensor setup suitable for each subsystem. The accuracy of the temperature sensor is measured, which verifies that the temperature sensor selection and set is reasonable and can ensure the good operation of the aircraft ECS.
Exploration of maintenance technology of aviation new energy power battery under machine learning
Authors: Song Shengli
Published: May 2024

The existing prediction models on the market have uncertainties and errors, which cannot accurately predict the remaining life of batteries. These problems lead to excessive or delayed maintenance of batteries, thereby affecting their performance and safety. Therefore, machine learning-based maintenance technology for aviation new energy power batteries has become a new research direction. This study used machine learning algorithms to construct a battery status classification and prediction model by collecting a large amount of aviation new energy power battery data. Through experiments, the model significantly improved its accuracy in battery status recognition tasks, with a maximum of 96%. It can accurately identify tasks such as battery health status, lifespan prediction, and fault detection. The model had made progress in balancing accuracy and recall, with a high F1 value. This meant that the model could accurately identify the abnormal state of the battery while minimizing misjudgment of normal batteries as much as possible. These research results provided important support for battery maintenance in the aviation field, with the potential to improve battery availability, extend service life, and ensure flight safety while reducing maintenance costs.
Simulation and analysis of the over-expanded flow field in asymmetric nozzles with lateral expansion
Authors: Yang Yalin , Yu Yang , Yu Tao , Mao Yuepeng
Published: May 2024

The study presented a numerical simulation of three-dimensional asymmetric nozzles featuring lateral expansion to investigate the flow field characteristics under over-expanded conditions and assess the influence of the lateral expansion angle. The research findings elucidate the distinct shape of the separation zones within the nozzle resulting from varying lateral expansion angles. In the restricted shock separation with separation bubbles forming on the flap pattern, the central separation bubble and corner separation bubbles exhibit independent characteristics. With an increasing lateral expansion angle under the same nozzle pressure ratio, the corner separation shock wave significantly impacts the shape of the central separation bubble.
Test and simulation of emergency flotation system buoy anti-overturning method
Authors: Yang Li , Huang Yanping , Sun Libing , He Fan , Zhu Yuanchun
Published: May 2024

The helicopter emergency flotation system can provide flotation capability after the helicopter accidentally falls into the water. During a test of a helicopter float in a submerged state, it was found that the vertical distance between the highest point of the contact point of the float and the aircraft and the lowest point of the cabin door was 0.59 m, which seriously hindered the entry and exit of the crew from the cabin door. To reduce the adverse effects of the pontoon flipping up on the occupants entering and exiting the hatch, it is envisaged to use restraint belts, add anti-rollover airbags, and design the anti-rollover airbags into triangles and saddle shapes respectively. Through theoretical analysis, the simulation method eliminated the triangle method for the connecting belt and the anti-rollover airbag and selected the saddle-shaped anti-rollover airbag for floating and immersion tests. The test results met expectations. The highest point of the contact point between the float and the aircraft was the lowest point of the cabin door. The points did not interfere in the vertical direction, and this method was finally chosen to be applied to the buoy to suppress the upturn of the buoy.
Numerical simulation of the effect of helicopter flight advance ratio and lift rate on rotor aerodynamic noise
Authors: Huang Surui , Sun Chengyuan , Yang Yaodong , Chen Hongchang , Yang Kai
Published: May 2024

To study the aerodynamic noise characteristics of helicopter rotors under different flight states, this paper combined with the FW-H calculation equation, adopted NACA0012 airfoil and ROBIN fuselage to form a helicopter model and used FLUENT software to simulate different flight states of the helicopter. The influence of the two flight parameters, advance ratios, and lift rates, on the aerodynamic noise characteristics of the rotor, is studied. The results show that with the increase of helicopter advance ratio, the aerodynamic noise generated by the rotor becomes larger, and the effect of helicopter lift rate on the aerodynamic noise of the rotor is not obvious.
Research on the mechanism of thermal-mechanical coupling effects of hypersonic aircraft rudder structure
Authors: Chen Hao , Zhang Yongli , Li Xiaopeng , Song Yiqiao
Published: May 2024

Hypersonic aircraft have achieved rapid development in the past decade, with flight speeds exceeding 5 Ma, posing a very severe aerodynamic and thermal environment for rudder structure. Especially for metal rudder wings, the extremely high temperature and temperature gradient makes the structural thermal response problem very prominent and complex. This article focuses on the study of the thermo-mechanical coupling response of the metal rudder wings of hypersonic aircraft in flight thermal environments. By simplifying the aerodynamic load and aerodynamic thermal environment under flight time sequence, a finite element model based on thermo-mechanical sequence coupling is established. The temperature, thermal stress, and deformation response curves of key parts are extracted, and the thermo-mechanical coupling response law of the rudder structure is explored. Based on the mechanical properties of structural materials at different temperatures, the corresponding relationship between stress and residual strength of key parts during flight time is obtained, and the safety factor of key parts of the structure is given.
Research on the de-tumbling method of magnetic moment variation of two stars based on the tangential formation
Authors: Li Ke , Shi Yongkang , Liao Qian
Published: May 2024

High-speed space debris threatens the safety of satellites in orbit, making the efficient removal of this debris an increasingly unavoidable necessity. By exploring the non-contact de-tumbling method for high-speed rotating targets, a de-tumbling technique is proposed. This method relies on leveraging the differential magnetic moments of two satellites arranged in tangential formation. Two single-coil electromagnetic satellites form a uniform magnetic field at the rotating targets, forming a tangential collinear distribution. The de-tumbling method of the simultaneous change of the magnetic moment of two satellites and the change of magnetic moment of one satellite and the other satellite is explored, and the de-tumbling effect is compared through numerical simulation. The simulation results indicate that the de-tumbling effect of the latter method is superior. Additionally, there is minimal variation observed in the relative distance between servicing stars and between servicing stars and target stars throughout the de-tumbling process.
Fixed-wing UAV based on vortex lattice method modular technology research
Authors: Xiao Hua , Su Xiaodong , Wang Yuan
Published: May 2024

The so-called modularity refers to dividing the system into several modules from top to bottom, layer by layer when solving a complex problem with various properties reflecting its internal characteristics. The main driving force for the demand for UAV modular technology comes from the requirements of UAV large-scale industrialization for UAV generalization, serialization, application scenario richness, and economy. The modular design of UAV is based on standardized software and hardware interfaces to carry out UAV aerodynamic shape module design, modular design of airframe structure, modular design of application load, module design of flight control system, module design of power system, etc.
A rapid time-coordinated longitudinal guidance method for high-speed vehicle
Authors: Li Xi , Gao Feng , Ma Aojia , Guo Dong
Published: May 2024

Compared to the traditional method of adjusting flight time by increasing lateral maneuverability [1-2], a faster time-coordinated longitudinal guidance method for unpowered high-speed vehicles has been proposed in this paper. Firstly, the centroid dynamics model and flight constraint model of unpowered high-speed vehicles were established, and the angle of attack corridor was derived based on quasi-equilibrium gliding conditions (QEGC). Then, to plan a reasonable angle of attack profile, the flight capability of a single vehicle under different constant angles of attack is analyzed, including terminal altitude, terminal velocity, and terminal arrival time. Furthermore, to achieve a long-term high angle of attack flight, a rapid time-coordinated longitudinal guidance method based on a trapezoidal angle of attack profile was proposed. Finally, using the vehicle and its performance parameters from Chapter 3 [3], numerical simulations were conducted under nominal tasks and multi-vehicle collaborative tasks. The simulation results show that under different expected arrival times, this method can quickly plan the angle of attack profile that satisfies time constraints, with high computational efficiency. Moreover, the arrival time adjustment ability of this method is large, which can fully utilize the arrival time capability of the high-speed vehicle. The above research provides more convenient conditions for a collaborative flight of multiple vehicles.
Research on case-based reasoning for determining maintenance intervals of civil aircraft systems
Authors: Ye Siyuan
Published: May 2024

The development of a rational and effective maintenance program is an important way to keep the safety and the economy of the aircraft industry. The maintenance program indicates maintenance types and intervals of all components. As development maintenance types of the components are simple, interval is a key to developing the maintenance program. In this paper, Case-Based Reasoning (CBR) is introduced to determine the intervals of components. It focuses on the expression and adjustments of the case. Finally, the reliability data of components in Boeing 737 is taken as an example to certify this method. The results show that this method can determine the maintenance intervals effectively, and so it has important engineering application value.
Research on civil aircraft fault diagnosis method based on selective integration
Authors: Ren Chenhui , Ma Linnlong , Wan Junlong , Huang Tianrui
Published: May 2024

Based on the research of the existing methods, this paper applies the performance parameters of the base learner and proposes the overall performance metrics of the base learner subset based on the diversity measurement method, the diagnostic accuracy of the base learner, and the running time. The performance metric as the fitness function of the genetic algorithm establishes the selection method of the subset of the base learner; the deep neural network is used to learn the complex nonlinear relationship between the base learners and a selective integration framework based on the stacking method is proposed to improve the overall diagnostic performance of integration model. Then, the data from engine operation to failure are used to verify the method performance proposed in this paper. The comparison results find that the method has a higher fault diagnosis accuracy and robustness. Finally, the method is streamlined to make it more applicable and suitable for engineering problems.