bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on pitting behavior of HDR duplex stainless steel at different film-forming potentials
Authors: Lin Yufeng , Li Zhuying , Liu Xin , Zhang Xiaodong , Chi Junhan
Published: March 2024

The influence of external potentials on the electrochemical corrosion characteristics and pitting resistance of Low Carbon High Chromium (H), Duplex (D), Corrosion Resistant (R) duplex stainless steel after film formation was investigated by techniques such as dynamic potential scanning, constant potential polarization, Electrochemical Impedance Spectroscopy (EIS), conjunction with Scanning Electron Microscope (SEM) and Energy Dispersive Spectroscopy (EDS) analysis, were used to examine the effects of passivation potential and over-passivation potential on the pitting resistance of HDR duplex stainless steel, compared with naturally film-formed HDR corrosion resistance. Results show that in a 3.5% NaCl solution, the passivation range of HDR duplex stainless steel is 0~1.0 V, with certain current fluctuation appearing in the unstable pitting region around 1.0 V. As the film formation potential increases, the impedance first increases then decreases, and the carrier concentration first decreases then increases. At 0.9 V, the impedance is at its maximum, the carrier concentration is at its minimum, and the corrosion resistance is the best; at 1.2 V, the impedance is at its minimum, the carrier concentration is at its maximum, and the corrosion resistance is the worst; the natural film formation sample falls between 0.1 V and 0.7 V. After pitting tests, pitting mainly occurs at the ferrite structure and its boundaries for the naturally film-formed and film-formed potentials below 1.0 V samples, but pitting mainly occurs at the austenite structure and its boundaries in the 1.2 V film-formed sample, indicating a reversal of corrosion in the structural pitting. The sample with the film formation potential of 0.1 V developed many small pits on the surface after pitting test, which is related to the oxidation of Mo.
First measurement of the (n,n′) reactions cross section in the 14 MeV regions using highly enriched 129,131Xe isotopes
Authors: Luo Junhua , Jiang Li , Tuo Fei , Liang Juncheng , He Long
Published: March 2024

In this study, the cross-sections of the 129Xe(n,n′)129mXe and 131Xe(n,n′)131mXe reactions were measured for the first time within the energy range 13.5–15.0 MeV based on the 27Al(n,α)24Na monitor reaction cross-section. The experiment employed high-purity, high-pressure, and highly enriched 129,131Xe isotope gas as the target sample. This study marks the first instance in which the measured cross-sections, corresponding correlation matrices, and associated uncertainties are provided. The TALYS-1.96 software was employed to obtain theoretical calculations, allowing for a comparison with experimental and evaluation results. The present study aids in understanding 129Xe(n,n′)129mXe and 131Xe(n,n′)131mXe cross-sections within 14 MeV regions, where the energy dependence exhibits relatively gradual changes and significant discrepancies between nuclear data libraries have been identified.
Research on vehicle battery data cleaning method based on OOA-VMD-ATGRU-GAN
Authors: Ding Delin , Sun Ning , Li Ai , Li ZiHan , Zhang Ying
Published: March 2024

Battery health monitoring is influenced by environmental and human factors, resulting in the presence of abnormal and missing values in the detection data. These issues compromise the accuracy of subsequent life prediction and fault diagnosis. To address this problem, we propose a deep learning-based method for cleaning battery anomalies and imputing missing data. Initially, we optimize the Variational Modal Decomposition method using the Osprey Optimization Algorithm to minimize the influence of continuous discharge processes on local anomaly detection. This process allows us to obtain the trend of the time series, and subsequently, we determine the anomalies by using the interquartile range after removing the trend components. The identified anomalies are then converted into missing values for further processing. Next, we fill in these missing values by constructing a Generative Adversarial Network. The generator structure of the network combines the attention mechanism with the Gated Recurrent Unit. We validate our approach using a real vehicle dataset and subsequently perform prediction on the cleaned dataset. Our results demonstrate that the subsequent Long Short-term Memory Networks and Gated Recurrent Unit prediction model improves the RMSE value by approximately 35% and the MAPE value by roughly 42%. Thus, our method effectively enhances the quality of the original data.
Axio-Chameleons: a novel string-friendly multi-field screening mechanism
Authors: Brax Philippe , Burgess C.P. , Quevedo F.
Published: March 2024

Scalar-tensor theories with the shift symmetries required by light scalars are well-explored modifications to GR. For these, two-derivative scalar self-interactions usually dominate at low energies and interestingly compete with the two-derivative metric interactions of GR itself. Although much effort has been invested in single scalars (on grounds of simplicity) these happen to have no two-derivative interactions, requiring such models to explore higher-derivative interactions (that usually would be less important at low-energies). This suggests multiple-scalar sigma models as well-motivated candidates for finding new phenomena in tests of gravity. We identify a new multi-field screening mechanism appropriate for two light scalar fields (an axion and a Brans-Dicke style dilaton) that relies on their mutual two-derivative interactions. We show how very weak axion-matter couplings can introduce axion gradients that can reduce the apparent coupling of the Brans-Dicke scalar to macroscopic matter sources. We further identify a relaxation mechanism that allows this reduction to be amplified to a suppression by the ratio of the axion gradient's length scale to the source's radius (similar in size to the suppression found in Chameleon models). Unlike some screening mechanisms our proposal is technically natural and works deep within the regime of control of the low-energy EFT. It uses only ingredients that commonly appear in the low-energy limit of string vacua and so is likely to have wider applications to models that admit UV completions. We briefly discuss phenomenological implications and challenges for this scenario, which suggests re-examination of decay loss bounds and the value of equivalence-principle tests for different-sized objects.
Analysis of the gluon distribution with next-to-leading order splitting function at small-x*
Authors: Chen 陈 Jingxuan 京萱 , Wang 王 Xiaopeng 晓鹏 , Cai 蔡 Yanbing 燕兵 , Chen 陈 Xurong 旭荣 , Wang 王 Qian 倩
Published: March 2024

An approximated solution for the gluon distribution from DGLAP evolution equations with the NLO splitting function in the small-x limit is presented. We first obtain simplified forms of the LO and NLO splitting functions in the small-x limit. With these approximated splitting functions, we obtain the analytical gluon distribution using the Mellin transform. The free parameters in the boundary conditions are obtained by fitting the CJ15 gluon distribution data. We find that the asymptotic behavior of the gluon distribution is consistent with the CJ15 data; however, the NLO results considering the "ladder" structure of gluon emission are slightly better than the LO results. These results indicate that the corrections from NLO have a significant influence on the behavior of the gluon distribution in the small-x region. In addition, we investigate the DGLAP evolution of the proton structure function using the analytical solution of the gluon distribution. The differential structure function reveals that our results have a similar tendency to the CJ15 data at small-x.
QCD sum rule study of J

P
= 1± exotic states with two heavy quarks in the molecular picture
Authors: Aliev T.M. , Bilmis S. , Savcı M.
Published: March 2024

In this study, the spectroscopic parameters of exotic molecular states composed of mesons containing two heavy quarks (scalar - axial and pseudoscalar - axial meson combinations) are investigated within the QCD sum rules. Our findings reveal that molecular states containing charm quarks do not form bound states, whereas states with b-quarks can form exotic molecular states. This observation has significant implications for understanding the structure of these exotic states.
BSN: Photometric Light Curve Analysis of Two Contact Binary Systems LS Del and V997 Cyg
Authors: Poro Atila , Tanriver Mehmet , Sarvari Elham , Zavvarei Shayan , Azarara Hossein , Corp Laurent , Baudart Sabrina , Ababafi Asma , Kahali Poor Nazanin , Zare Fariba , Bulut Ahmet , Keskin Ahmet
Published: March 2024

The light curve analyses and orbital period variations for two contact binary stars, LS Del and V997 Cyg, are presented in this work which was conducted in the frame of the Binary Systems of South and North project. Ground-based photometric observations were performed at two observatories in France. We used the Transiting Exoplanet Survey Satellite (TESS) data for extracting times of minima and light curve analysis of the target systems. The O − C diagram for both systems displays a parabolic trend. LS Del and V997 Cyg’s orbital periods are increasing at rates of dP/dt = 7.20 × 10−08 days yr−1 and dP/dt = 2.54 × 10−08 days yr−1, respectively. Therefore, it can be concluded that mass is being transferred from the less massive star to the more massive component with a rate of dM/dt = –1.96 × 10−7
M
⊙ yr−1 for the LS Del system, and dM/dt =–3.83 × 10−7
M
⊙ yr−1 for V997 Cyg. The parameters of a third possible object in the system are also considered. The PHysics Of Eclipsing BinariEs Python code was used to analyze the light curves. The light curve solutions needed a cold starspot due to the asymmetry in the LS Del system’s light curve maxima. The mass ratio, fill-out factor, and star temperature all indicate that both systems are contact binary types in this investigation. Two methods were applied to estimate the absolute parameters of the systems: one method relied on the parallax of Gaia DR3, and the other used a P − M relationship. The positions of the systems are also depicted on the M − L, M − R, q − L
ratio, and

log

M

tot

−

logJ

0

diagrams. We recommend that further observations and investigations be done on the existence of a fourth body in this system.
Summary of the 17th Asian International Conference on Fluid Machinery
Authors: Shouqi Yuan
Published: March 2024

1. Background

The conference is a continuation of the preceding 16th conferences that have been held in the name of the Asian International Conference on Fluid Machinery (AICFM). It has developed from the fourth conference (1993) as an International Conference though the start was held in two countries of Japan and China. After that the conference was held in Seoul (1997), Johar Baru (2000), Fukuoka (2003), Yichang (2005), Jeju (2007), Kualalumpur (2009), Chennai (2011), and Yogyakarta (2013), Tokyo (2015), Zhenjiang (2017), Busan (2019) and Yokohama (2021). The Asian Fluid Machinery Committee (AFMC) was established during the 9th AICFM 2007 held in Jeju, Korea.

The conference is organized by AFMC and CSET. Participation of those who are relevant to every facet of fluid machinery, R&D will be encouraged.

List of Objectives, Scope, Record, Acknowledgement, Appendix A. Organization, Appendix B. Committee Members, Appendix C. AFMC AWARD 2023 Winners, Appendix D. Excellent Papers are available in this pdf.
Research on the influence of piping system on the fluid-dynamic noise of centrifugal pump
Authors: Mao Jieyun , Li Guidong , Zheng Yi , Zhang Jinfeng , Wang Peng
Published: March 2024

During the experimental research of the fluid-dynamic noise generated by a centrifugal pump, the accurate measurement of its acoustic characteristics can only be achieved when the pump is connected to a pipeline system. If the noise at a specific position of the centrifugal pump or its suction and discharge pipelines is used to directly describe the internal sound source characteristics of the pump during the test, there may be a broad difference in the experimental data depending on the specific system and the measuring position. Therefore, in order to verify the influence of different piping systems on the acoustic characteristics at a certain position of the inlet and outlet pipeline of the centrifugal pump, three different discharge pipeline schemes of the piping system were set up in this study. Meanwhile, this study solved the scattering matrix of a centrifugal pump using experimental methods. This method can be used independently of the testing system to describe the transmission and reflection characteristics at the ports of a centrifugal pump, and accurately solve the acoustic characteristics of the pump itself in future research.
Effect of reduced diameter pipeline and impeller position on the performance of reactor coolant pump
Authors: Su Haonan , Chen Huazheng , Zhu Rongsheng , Fu Qiang
Published: March 2024

In the reactor coolant pump experiments, there are cases where different impellers are replaced on the same volute for experiments, but due to the different diameter of the impeller inlet, there will be a sudden expansion between the inlet pipeline and the impeller inlet, resulting in a decrease in the efficiency of the pump. In order to solve this problem, a scheme of using an inlet pipe with a reduced diameter structure and changing the position of the impeller was proposed, and based on the three-dimensional incompressible Reynolds N-S equation, the reactor coolant pump device was numerically simulated by CFD software. The data simulation results of the reduced diameter structure, straight pipe flow field and changing the position of the impeller were compared with the model experiments, and the reliability of the calculation results was verified. The results show that the inlet pipe with reduced diameter structure and the method of changing the position of the impeller can effectively solve the problem of efficiency decline caused by the sudden expansion of the flow channel.
Effect of sand diameter on the performance of annular jet pumps
Authors: Liu Wenhui , Lai Xinjie , Zhu Chenbing , Zhou Qiwei , Yang Xuelong
Published: March 2024

For the current problem of low efficiency of the annular jet pump in transporting particles, the effects of different sand diameters on the flow field, pressure and efficiency inside the annular jet pump are analysed, in order to improve the structure of the annular jet pump to adapt to the transport of solid particles. The results show that when the flow rate is relatively small, due to the small flow rate of the suction mixture, it can not meet the suction capacity of the primary flow, which causes reflux in the suction chamber or throat; with the increase of the flow rate ratio, the transport capacity of the annular jet pump for the sand shows a parabolic growth, so to maintain the efficient transport capacity, the flow rate ratio should be selected between 0.4-0.7; the efficiency of sand transport of the annular jet pump is much higher than that of the centre jet pump, and it is much higher than that of the centre jet pump. Annular jet pump compared to the centre of the pump transport sand efficiency appeared the opposite phenomenon.
Effect of the difference in slit locations on the suppression of cavitation instabilities in an inducer.
Authors: Ishikawa Naruki , Nakura Yuto , Kawasaki Satoshi , Shimagaki Mitsuru , Iga Yuka
Published: March 2024

Cavitation instabilities are caused by unsteady cavitation in the inducer in liquid rocket turbopumps. This phenomenon has a negative impact on pumps and must be suppressed. Our research group has proposed a method to suppress the instabilities by adding slits to the inducer blades, and previous studies was shown the effectiveness of this method. In this study, water experiments of inducers with slits at different locations were conducted. As a results, the vibration characteristics of cavitation in the slit inducers changed when the location of the slit was changed although the cavitation instabilities were successfully suppressed in all slit inducer. The visualized image of cylindrical surface of the axial flow pump was expanded into a two-dimensional plane to determine the time variation of the area of the tip leakage vortex cavitation generated in each blade. The suppression mechanism of cavitation instabilities in each slit location was discussed from the obtained unsteady image of cavity area in each blade in the slit inducers.
The effects of balancing holes on the axial force of a centrifugal pump in the reverse mode
Authors: Fathi Mohammad , Alemi Hamed , Raisee Mehrdad , Nourbakhsh Ahmad
Published: March 2024

Centrifugal pumps can feasibly act as turbines in small hydropower plants. However, prediction and reduction methods of axial force is still challenging. A proposed method to this goal is the use of balancing holes. Accordingly, this paper investigates the effect of balancing holes diameter on the hydraulic performance and the axial force of a centrifugal pump as turbine (PAT). In this study, modeling of the fluid flow within the pump was carried out by using the commercial software of Ansys CFX R19.0 and the SST turbulence model. The numerical results showed that by working in the reverse mode, the operating flowrate, head and the axial force of the pump are increased remarkably. This study proved that drilling balancing holes in the impeller, despite being simple, is a useful method in reducing the axial force and has minor effects of the output power. Results showed that by drilling a hole of diameter 2 mm, the axial force is approximately decreased by 60 % in almost all flowrates. Finally, it is observed that increasing holes diameter is mostly influential at high flowrates, and with diameter of 6.5 mm, the axial force is reduced about 90%.
Optimization design of low specific speed shield pump based on orthogonal experiment
Authors: Qiu Gai , Wang Wenjie , Pei Ji
Published: March 2024

Low specific speed pump is characterized by generally low efficiency, easy to appear hump and optimization difficulties. In order to improve the hydraulic performance of the pump at the shut-off point (0.2Q
d) and reduce the hump phenomenon, the influence of impeller geometric parameters on the hydraulic performance of the pump is analyzed without changing the volute structure, the orthogonal experimental design of impeller parameters is carried out. Six geometric parameters, including impeller outlet diameter, impeller outlet width, blade inlet angle, blade outlet angle, wrap angle and blade thickness, are selected as design factors. Each parameter factor is taken to 3 levels, and a total of 18 schemes are designed. 3D impeller design is carried out based on CFturbo, numerical simulation is carried out with CFX. The results show that increasing the impeller outlet diameter can increase the head within a certain range. The impeller efficiency can be improved by reducing the outlet width of the impeller, increasing the blade inlet angle and increasing the wrap angle. The pump performance parameters before and after optimization are analyzed and compared, it is verified that the orthogonal experimental design method combined with numerical simulation can optimize the design of low specific speed shield pump.
Analysis of energy dissipation in allowable, restricted and prohibited operating areas of wanjiazhai francis turbine
Authors: He Gensheng , Pan Jiale , Su Lifeng , Song Xijie , Wang Zhengwei , Zhu Di , Tao Ran
Published: March 2024

With the “14th Five-Year Plan” and the “two-carbon” policy, the application of renewable energy has seen a substantial increase. As a kind of hydraulic machinery which converts the kinetic energy of water into electric energy, the turbine is widely used in various hydropower stations. However, due to the variability of flow rate, speed and head, how to ensure the efficiency of unit operation is particularly important in complicated working conditions. In this study, the Francis turbine of Wanjiazhai Hydropower Station is taken as the research object. Through the combination of numerical simulation and experiment, the energy consumption under the permitted, restricted and forbidden conditions is analyzed.
Simulation of water hammer in long distance water transmission pipeline based on Flowmaster
Authors: Guo H L , Chen J
Published: March 2024

Long distance water transportation projects are widely used in balancing water resources and other fields. However, the opening and closing of valves often causes significant pressure changes in the pipeline, whether it is positive or negative pressure, which can cause damage to the pipeline, thereby affecting the actual water transportation project. Therefore, based on the method of characteristics, this paper studies the influence of pipeline diameter, length, friction coefficient and valve closing time on the transient flow in the pipeline. The results indicated that the pressure pulsation inside the pipe is mainly concentrated at 0.4hz and its harmonics. In addition, the frequency with high amplitude mainly ranges from 2.5s to 10s, and the closer it is to the valve, the higher the amplitude at the node.
Hydrodynamic performance study of shore-based oscillating water column wave energy conversion device
Authors: Ding Jiawei , Pang Shujiao , Chen Zhenmu
Published: March 2024

To cope with the increasing energy demand, countries have started to actively develop renewable energy. Therefore, the study of wave energy generation devices is an important issue. In this paper, we investigate the performance and characteristics of shore-based oscillating water column wave energy generators concerning structural dimensions such as front wall draft and water depth variation. The results show that the front wall draft have significant effects on the internal flow characteristics of the oscillating water column wave energy generator. When the draft of the front wall changes, the reflection coefficient of the air chamber changes accordingly and the performance changes significantly. The variation of water depth has less effect on the performance of the low-frequency region of the oscillating water column wave energy generation device.
Flow analysis through center body of ducted fan to electric motor cooling
Authors: Dinh Van-Son , Chu Hoang-Quan , Nguyen Trung-Kien , Le Dinh-Anh , Le Ngoc-Bon , Nguyen Anh-Tuan , Kim Kwang-Yong , Dinh Cong-Truong
Published: March 2024

In recent years, electric Vertical Take-Off and Landing aircraft (eVTOL) have been increasingly researched and developed because of their high applicability: parcels and deliveries, rescue, military, etc. These flying machines typically use an Electric Ducted Fan (EDF) driven by an Electric Motor located within the Centre Body of this EDF. In this study, several ventilation hole concepts on the Centre Body were given to increase the cooling ability of the Electric Motor. Two-way heat transfer method were implemented to simulate the conductive and convective heat transfer phenomenon between the Computational Fluid Dynamics and Finite Element models in the cases with and without the ventilation holes. The validation of the model’s accuracy was done by comparing separately the simulation results of the EDF and the Electric Motor with the experiment data and the previous research result, respectively. The results show that the most effective ventilation hole configuration has reduced the temperature of the Rotor, End-Winding Forward, and End-Winding Rear respectively 6.66 °C, 5.54 °C, and 6.8 °C.
The experiment of rotating detonating engine using an asymmetric vortex shape on an annulus chamber
Authors: Dairobi G. A. , Wahid M.A.
Published: March 2024

Rotating detonating engine is new propulsion technology with promising advantages. Higher thermal efficiency and simple design with higher thrust attracted intention worldwide to make it realistic. The normal design uses a circular shape of an annulus chamber. The circular shape of the annulus chamber was well-known and tested with various conditions. The new interest area of changing a circular shape into an asymmetric shape is still unknown. Exploring the new shape of the annulus chamber was done by applying the new shape of the annulus chamber on RDE. The experiment was successfully done using methane at different conditions. Three modes can be observed from pressure product and thrust result: a mode of detonation, unstable detonation, and failure on transition. The highest thrust happens at an equivalence ratio of 1.2 with 18N. The new shape of the annulus offers the versatility of RDE.
Effect of multiple factors on sediment erosion characteristics of hydro turbine materials
Authors: Yang Junfeng , Wu Pengbo , Song Guohua , Sun Shuaihui , Wang Kai
Published: March 2024

Hydraulic turbines on sediment-laden rivers suffer from cavitation-silt erosion. This study conducted cavitation-silt erosion tests on three materials (06Cr16Ni5Mo, Q355B, 06Cr20Ni11) with different sediment concentrations and impact velocities using a rotating disk facility, and used a scanning electron microscope (SEM) to observe the cavitation-silt erosion characteristics of the materials. The results show that the cumulative weight loss of all materials continuously increases with the sediment concentration and impact velocity rises. The weight loss of 06Cr16Ni5Mo is the lowest, and 06Cr20Ni11 is the highest. As the impact velocity rises, the cumulative weight loss increases exponentially. As the sediment concentration rises, there are obvious scour marks and fatigue spalling on the material surface. As the impact velocity rises, the size and depth of micro-cutting marks and cavitation pits increases. Due to the lower surface hardness of 06Cr20Ni11, the deep platelet pits appear on the material surface.
Experimental study on the optimum number of layers of fiber mats for gas-liquid coalescer
Authors: Chaolei W , Zhiqian S , Zhenbo W , Liyun Z , Yijie L , Jianhua Z , Yu L , Zhilong D
Published: March 2024

The coalescer is widely used in deep gas dehydration due to its high efficiency. Most manufacturers make the filter by enwinding multiple layers of fiber mats to obtain high efficiency, which leads to high-pressure losses in practical applications. Obtaining the number of layers of fiber mats is based on engineering practice and experiences, which needs more data support and theoretical basis. 1-10 layers of hydrophilic fiber mat samples were made, and experiments were carried out at filter face velocities of 0.14m/s to 0.35m/s and liquid loading rate of 1.25g/min to 5g/min. In addition, the concept of collision probability based on fiber porosity is invoked. A model between efficiency and porosity is developed to obtain the optimal solution for the number of layers. The results show that the saturation is monotonically decreasing, while the pressure drop linearly increases as velocity increases. The optimum number of fiber mat layers decreases from 5 to 3 as the filter face velocity increases. The efficiency model based on the fiber porosity agrees with the experimental efficiency values, which provides theoretical support for calculating the optimal number of fiber mat layers.
Numerical simulation study of particle self-rotation velocity in cyclone separator
Authors: Liu Tielin , Heng Yaguang , Jiang Qifeng , Chen Zhengsu , Luo Xipeng
Published: March 2024

Cyclone separators are widely used in petrochemical, environmental protection and other fields. Taking the cyclone separators with single volute inlet as the research object, in order to study the particle self-rotation velocity and motion trajectory in its internal flow field, the Reynolds stress model (RSM) was used for the gas phase and the discrete phase model (DPM) was used for the solid phase. The tangential velocity distribution and the particle motion trajectory were obtained through numerical simulation, and the tangential velocity was used to derive the formula for the particle self-rotation velocity, and self-rotation velocity distribution obtained by writing expressions in Fluent. The results show that: in the internal flow field of the cyclone separator, the place with large velocity gradient will present a larger self-rotation velocity; when the particle size is 14.44 μm and the inlet air intake is 212 m3/h, the particles can be stably suspended in a certain region of the cylindrical section.
Study of adsorption of Congo red on ferric oxide@straw magnetic composites
Authors: Qu Yanping , Ma Huimin , Liu Jiabin , Luo Yuyue , Yue Yinqi , Wang Jingqi , Cheng Ying
Published: March 2024

In this paper, citric acid-modified corn stalk and Fe3O4 were used to make magnetic straw adsorbent to realize rapid separation of adsorbent and wastewater. The influences of pH, dosage, reaction time, and initial stress on the Congo red adsorption rate were investigated. Then, we used adsorption kinetics and isothermal linear adsorption adjustment to explore the adsorption mechanism. Studies have shown the increasing doses of magnetic adsorbents on straw. When the dose was 8 g/L, the commercial adsorption rate was 95%. The adsorption process of magnetic straw adsorbent for Congo red was exothermic. Adsorption was mainly chemisorption, and the adsorption process was relatively fast, reaching adsorption equilibrium after about 90 min.
Study on synthesis and characterization of a novel pyridine imide ligated rare earth metal complex C28H51N2Ln (THF)n(CH2 SiMe3)3 (Ln = Sc, Y) and its catalytic performance in polymerization of isoprene
Authors: Lu Yongqiu , Li Xiaofang
Published: March 2024

We simply synthesized the pyridine imine rare earth trialkyl Figures (2, 3) by using the isofold scandium trialkyl complex Sc3(THF)2.5(CH2SiMe3) and the Yttrium trialkyl complex Y(THF)2.5(CH2SiMe3)3 with the pyridine imine derivative ligand (1: C28H51N2Sc (THF) (CH2SiMe3)3; 2: C28H51N2Y(THF)0.625(CH2SiMe3)3. In situ, nuclear magnetic resonance (NMR) showed that for pyridine imine rare earth trialkyl Figures (2, 3), different feed ratios of borate [Ph3C] [B(C6F5)4] to catalyst and different feed sequences of borate and alkyl aluminum can produce different catalytic active species. These catalytic active species can realize high activity (4.08 × 104g·molSc
−1·h−1), high selectivity, and narrow molecular weight distribution (1.4) polymerization of conjugated diene such as isoprene.
Study on conversion of glucose into HMF based on coordination of MIL-101(Cr)/Cr(OH)3 @[A-15 x%] composite with DBD plasma
Authors: Wang Lerao , Tao Xumei
Published: March 2024

Glucose was highly economical as a reactant for the catalytic formation of 5-hydroxymethylfurfural (HMF). However, the regulation method of glucose conversion to HMF requires high temperatures. Dielectric barrier discharge (DBD) plasma could realize glucose conversion in low-temperature conditions. Glucose could be isomerized to fructose on Lewis acid, and remove H2O to form HMF on Brønsted acid fructose. A variety of by-products were generated in the process of isomerization and dehydration, and thus the regulation of the Brønsted-Lewis acid site in the catalyst was essential in the targeted formation of HMF. Using Lewis acidic MIL-101(Cr) compounded with Brønsted acidic Amberlyst-15, a bi-functional catalyst MIL-101(Cr)/Cr(OH)3@[A-15 x%] was obtained. By coordinating it with DBD plasma on glucose conversion, 80.6% of the glucose conversion rate and 5.3% of HMF yield were obtained.
The discussion of dynamic modulus of asphalt mixtures under biaxial stresses
Authors: Gao Tao , Wu Lei , Liu Heng , Wei Ankang
Published: March 2024

Asphalt pavement in service is subjected to a complicated state of stress, especially in the uphill or starting and braking sections. The normal stress and the shear stress load it together. Only uniaxial vertical load was taken into account in the testing of dynamic modulus when a pavement was designed at present. In this paper, the dynamic response tests were carried out by applying the dynamic normal and shear loads to cylindrical specimens of asphalt mixtures. The dynamic modulus under vertical loading and vertical-horizontal loading were compared to analyze the effect of the combination loading. The result indicated vertical dynamic modulus under biaxial loading was significantly lower than vertical loading, as opposed to dynamic shear modulus. It could be concluded that the properties of asphalt mixture from biaxial stresses state should be paid more attention in the design of pavement, especially in the intersection and uphill sections.
Study on the brittle-plastic transition of YAG crystals based on nano-scratch experiments
Authors: Ma Rongguo , Zhang Qingli , Gao Jinyun , Sun Guihua , Dou Renqin , Han Song , Zhang Rui , Chen Zhao , Wang Xiaofei , Sun Yu , Liu Wenpeng
Published: March 2024

YAG crystals are typically hard and brittle materials that are prone to be damaged during optical processing. In order to improve processing quality, it is necessary to avoid brittle damage as much as possible so that the material is removed in the plastic domain, so it is particularly important to study the critical conditions for the brittle-plastic transition of YAG crystals. The brittle-plastic transition of the (100) and (111) crystal faces of YAG crystals was investigated by variable load and constant load nano-scratch experiments. By analyzing the scratch morphology and friction-scratch distance curves, the critical load of brittle plastic transition for each crystal surface is obtained. The results show that the critical loads of (100) and (111) crystal faces for brittle-plastic transformation under variable load nano-scratch experiments are 113.575 mN and 84.05 mN, respectively, and the different critical loads of the two crystal faces are due to the discrepancy of surface energy. According to Griffith’s fracture theory, because the surface energy of (100) crystal face is higher, the energy required for brittle fracture of the crystal surface is higher, so the critical load of brittle-plastic transition is larger. Finally, the correctness of the critical load was verified by constant load nano-scratch experiments.
Failure analysis of 316L stainless steel corrugated pipe
Authors: Tao Kangning , Hu Shusen , Dai Zhen
Published: March 2024

316L stainless steel is a kind of austenitic stainless steel with good corrosion resistance, widely used in power plants, refineries, chemical plants, etc. However, the metal bellows manufactured by 316L stainless steel have caused a corrosion perforation phenomenon in the Cl−environment, which will affect the safety of equipment operation. In this paper, by observing the corrosion morphology, examining and analyzing the material composition, corrosion products, working conditions, and production process of the metal bellows of a power generation company. The results show that the main cause of failure of stainless steel corrugated pipe is pitting corrosion perforation caused by high concentration chloride aqueous solution in the medium.
Study on source and control of high Al2O3 containing inclusions in tire cord steel
Authors: Zhang Zhenglin , Yu Fei
Published: March 2024

The composition, size and morphology of inclusions that initiated the fractures of the tire cord during fabrication were investigated to decrease the breakage frequency of the saw wire. It was found that they were high melting point inclusions in lumpy shapes and large sizes, highly composed of Al2O3. Characteristics of inclusions appearing on the fractures were compared to inclusions observed in wire rods and materials of refractory used in the steelmaking process. The obtained results indicated that refractories used in the steelmaking process were the possible contamination sources of alumina inclusions. The frequencies of wire breakage caused by inclusions in the wire drawing process could be remarkably reduced from 4.2 to 1.5 times/ton by changing the refractories used in casting into non-Al2O3-based.
Study on electrochemical properties of Pt-Ni nanocatalysts with high index crystal facets
Authors: Guo Ruihua , Wurentuoya  , An Shengli , Zhang Wenyu , Zhang Guofang , Huang Yarong , Guan Lili , Zhu Guofu , Guo Xiong
Published: March 2024

We prepared Pt-Ni high-index crystalline nanoparticles with various Pt-Ni molar ratios to study the microscopic morphology and electrochemical properties of these catalysts. The results demonstrated that when Pt: Ni is 1:1, the prepared catalyst has the most uniform morphology and the optimal catalytic activity, as evidenced by an electrochemical active area of 8.546 m2/g, the current density of 1.544 mA/cm2 for ethanol oxide and 1100 s steady state current density of 1.132 mA/cm2. Pt-Ni high-index crystalline nanocatalysts have such high catalytic efficiencies due to the abundance of step atoms and the doping of non-precious metal nickel.
Study on annealing effect of Ti-doped Gd2O3 films for high k dielectrics
Authors: Li Shuan , Wu Daogao , Wang Shuang , Yang Hongbo , Li Xingguo
Published: March 2024

Rare earth oxides and nitrogen oxides have drawn more and more focus as candidates for next-generation gate dielectrics in MOSFET. In this study, a Gd2O3 film doped with 3% Ti was fabricated through co-sputtering gadolinium and titanium targets in a diluted oxygen atmosphere. A systematic study was carried out to examine the annealing influence on the microstructure, surface roughness, band gap, and electrical properties of this film. Compared with as-deposited film, the annealed sample displays a smaller surface roughness (Ra=0.45 nm) and more excellent electrical performance. In terms of band gap analysis, as the annealing temperature rises from 400 to 700°C, the band gap has fallen from 4.70 eV to 4.63 eV, indicating a smaller value compared to the as-deposited sample (4.73 eV). As a result, the 600°C-annealed thin film shows the most outstanding performance with the largest k value of 23.9. Further, 600°C-annealed and as-deposited films were selected for impedance spectrum analysis and examination of the equivalent circuit. This work can offer a new insight to design novel rare earth oxides with high k dielectric and select the corresponding annealing process.
Cp*Co(III)-catalyzed C-H bond amination of indoles with arylazide compounds
Authors: Niu Ruihan , Li Ting , Sun Bo
Published: March 2024

Indoles are an important class of intermediates found in drug molecules and functional materials, so structural modification of indoles is necessary. We have developed an inexpensive and readily available transition metal cobalt(III) catalyzed selective C-H amination reaction of indoles with azides at the C2 position, which has high functional group tolerance. It provides an effective way to synthesize a range of 2-aminoindole derivatives using an environmentally friendly and resource-efficient catalytic system, paving the way for expanding the application of indole structures.
Saturated vapor pressure measurement and fitting analysis of green insulating gas C4F7N within the temperature range of 251 to 309 K
Authors: Liu Wei , Dong Li , Ma Fengxiang , Jia Xiaoqing , Cao Jun
Published: March 2024

Perfluoroisobutyronitrile (C4F7N) is an environmentally friendly SF6 substitute with excellent insulation performance and safety, which is a focal point in the field of power insulation. This paper employs vapor pressure measuring instruments to gather 59 groups of saturated vapor pressure data of C4F7N within the temperature range of 251 to 309 K. The experimental data are fitted with the Peng Robinson equation, Antoine equation, and the “2.5, 5” Wagner equation. The following deviation analysis of the results reveals that the Wagner equation yields the most optimal fitting performance, with the absolute, relative, and average deviation percentages of ±0.5 kPa, ±0.3%, and 0.095%, respectively. These results fulfill the requisites of engineering design, applied research, and thermodynamic computations.
Adapter molding and heat transfer analysis
Authors: Jiang Ming , Zhou Kexu , Shen Feng , Zhou Linyun , Chen Yongxiao
Published: March 2024

In this paper, we investigated the excessive thermal stress caused by the difference in the coefficient of thermal expansion of the material during the molding process of the adapter. It has led to the bulging phenomenon during the high and low-temperature tests. We analyzed the heat transfer mechanism of the adapter during the high and low-temperature tests by using finite element simulation. We then analyzed the causes of the bulging phenomenon. We successfully solved the bulging problem by using the method of heating up the foamed adapter together with the mold for curing, which provided a new idea for adapter molding.
Study on the high-temperature oxidation behavior of Mg-Ce binary alloys
Authors: Yu Xiaowen , Yang Jiping , Han Guangjie , Chen Sanxing , Li Jing , Zhou Wang , Wei Yanhong
Published: March 2024

The aim of current research is to study the oxidation resistance of binary magnesium alloys containing Ce at high temperatures to provide a theoretical foundation for the application of magnesium alloys which are applied at high-temperature conditions. The oxidation properties of binary magnesium alloys containing different Ce content at high temperatures have been studied. The thermogravimetric results show that a small amount of Ce (0.2, 0.4 wt. %) addition can improve the oxidation resistance of magnesium alloys at high temperatures. Continuous-distributed Mg12Ce compounds in the two test alloys with high Ce content (≥0.7 wt. %) provided channels to the internal oxidation and thus deteriorated the oxidation resistance. MgO and CeO2 were the primary components which are detected in the oxide films. CeO2 was mainly detected at the inner layer of the film.
Study on Novel Pd-impregnated Catalyst for Synthesis of 2-Arylpropanoic Acids by Hydrocarboxylation
Authors: Ma Mengchuan , Tao Yong , Guo Zhenmei , Lv Zhiguo
Published: March 2024

In the hydrocarboxylation of the Pd-based catalyst, the heterogeneity of homogeneous processes was a reliable means to improve the recyclability of the catalyst and to inhibit the loss of noble metals. Herein, a novel heterogeneous Pd@DT017 catalyst prepared from Pd(II) salt impregnated in the acidic resin of DT017 had been studied, which revealed high performance. Correcting characterization showed that Pd(II) was successfully grafted to -SO3
- on the surface of DT017, and the Pd element was highly dispersed in DT017 with the macroporous structure. The conversion was 99.9%, and the yield of isomeric acid was 91.6% on Pd@DT017. The stability test found that Pd@DT017 had higher cycle stability.
Preparation and characterization of water-based adhesive and its application in radiation-cooling coatings
Authors: Jin Fuguo , Liu Guoqing , Shi Qiguang , Li Tiancheng , Yang Chen
Published: March 2024

In order to prepare environmentally friendly coatings with radiative cooling performance in the middle and low-temperature domain (below 150°C), this paper first prepared a water-based adhesive. The preparation and test methods and results are as follows. The siloxane-coated cadmium telluride composite particles were prepared, and the surface layer was modified by amination with silicone coupling agent KH550. The modified composite particles were used to crosslink waterborne polyurethane to prepare waterborne adhesive and waterborne radiation coating. The composite particles and their modified aqueous emulsion film were characterized by XRD, FT-IR, TEM, TGA, and universal tester. Besides that, three kinds of water-based adhesives with different cadmium telluride content were prepared into radiation-cooling coatings and coated on steel plates. The temperature was raised to 70°C together with the uncoated steel plates, and then the temperature was lowered naturally. The cooling time of 4 steel plates to 30°C was recorded. The results show that the composite particles are microspheres, uniform in size and narrow in distribution. The radiation coatings prepared with three kinds of binders have good cooling and radiation performance, and the cooling performance increases with the increase of cadmium telluride content in the coating.
Unraveling the effects of solution treatment on the microstructure and corrosion behavior of HT-HAZ in duplex stainless steel welded joints
Authors: Shen Kuiling , Jiang Wenchun
Published: March 2024

In this work, the influence of solution treatment on the corrosion behavior and microstructure of HT-HAZ was studied. The results show that the balanced two-phase ratio is discovered after solution treatment. After solution treatment at 960°C, a small amount of chromium nitride remains at the two-phase interface and in the ferrite. With the solution treatment temperature increasing to 1120°C, chromium nitride can be fully dissolved. The chemical elements of the two-phase are redistributed during the solution treatment process, which results in changes in PREN. After solution treatment, the proportion of recrystallized grains increases whereas that of sub-structured grains decreases, indicating the reduction of residual stresses and deformations. The percentage of CSL boundaries increases as the solution treatment temperature rises. Compared with HT-HAZ without solution treatment, the improved corrosion resistance after solution treatment is ascribed to the balanced two-phase ratio, less chromium nitride precipitates, smaller residual deformations, and more CSL boundaries. However, the pitting resistance after solution treatment at 960°C is still relatively poor on account of the residual chromium nitride. The pitting nucleation sites are closely associated with the chromium nitride precipitates and PREN of two-phase.
A novel organic interface layer material to improve the efficiency of solar cells
Authors: Ouyang Shijun
Published: March 2024

Compared with the mature inorganic silicon solar cells[1] and perovskite solar cells[2], OSC is slightly obviously immature in terms of short service life and bad power conversion efficiency (PCE)[3]. Therefore, how to improve its durability and PCE to promote its development has become the main research direction. For solar cells, one of the most effective methods to improve their performance is to introduce different materials to optimize the electron transport layer to improve the charge transport characteristics inside the cell[4]. For organic solar cells, it is to modify the existing materials, introducing organic[5] (e.g. conductive polymer or polyelectrolyte) and inorganic[6][7][8] (e.g. metal oxide) interface modification layers to optimize this layer, so as to realize the regulation of interface energy level and improve PCE.

In this work, the method of introducing an organic interface modified layer and reasonable experimental steps is used to synthesize non-conjugated polymer polyimide derivatives (BDI-RO). Combined with various photoelectric test methods and according to the work function and optical band gap of the modified interface layer, the effect of using BDI-RO as a cathode interlayer on the performance of OSC is studied and discussed.
Ambiguity, invisibility, and negativity
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Authors: Wilczek Frank
Published: March 2024

Many widely different problems have a common mathematical structure wherein limited knowledge leads to ambiguity that can be captured conveniently using a concept of invisibility that requires the introduction of negative values for quantities that are inherently positive. Here I analyze three examples taken from perception theory, rigid body mechanics, and quantum measurement.