bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nutrient status assessment and mapping of intensively managed paddy soils in southeastern hilly areas of Bangladesh
Authors: Hosenuzzaman Md , Kibria Mohammad Golam , Abedin Md Anwarul 
Published: September 2023

AbstractBackgroundPeople living in the southeastern hilly areas of Bangladesh are primarily dependent on agriculture and face the problem of nutrient deficiency in soils. This research was conducted to assess the fertility status of paddy soils for better fertilizer management. Grid sampling (1 km × 1 km) was followed to collect soil samples, avoiding unusual spots (e.g., non‐agricultural land, settlements, hills, and forests). In total, 300 samples were collected (150 from each upazila) to assess the status of soil physical properties (soil texture) and chemical properties (pH, electrical conductivity, organic matter, and nutrients [nitrogen (N), phosphorus (P), potassium (K), sulfur (S), magnesium (Mg), boron (B), and zinc (Zn)]).ResultsResults revealed that most of the soils were sandy to silt loam in texture. The soils were found to be strongly acidic with values of 4.79 and 4.73 in Ukhiya and Teknaf, respectively. Most of the soils were found to be nonsaline, except the paddy soils close to the sea and/or salt‐affected cultivated land. Soil organic matter in Ukhiya and Teknaf was low (1.47% and 1.43%, respectively). The soils in both upazilas were deficient in N, P, K, S, and Zn, but not in Mg in both upazilas and B in Teknaf.ConclusionIt is imperative that adequate amounts of nutrient provision are available to maintain soil health and produce a sustainable crop yield. We believe that these are the first digital soil maps developed at upazila level using ArcGIS software, which will be available for future reference.
Classification of Greek extra virgin olive oils by Raman spectroscopy in conjunction with sensory and cultivation characteristics, and multivariate analysis
Authors: Philippidis Aggelos , Kontzedaki Renate , Orfanakis Emmanouil , Fragkoulis Nikolaos , Zoumi Aikaterini , Germanaki Eleftheria , Samartzis Peter C. , Velegrakis Michalis 
Published: September 2023

AbstractBackgroundExtra virgin olive oil (EVOO) is a natural product with numerous health benefits and superior quality compared with other vegetable oils. To characterize a sample as EVOO, it is necessary to perform a sensory evaluation through a testing panel, in addition to conducting physicochemical measurements. Moreover, distinguishing between organic and conventional production has captured the attention of those involved in the olive oil industry. The current study demonstrates the utilization of Raman spectroscopy in combination with multivariate statistical analysis for the examination of extra virgin olive oil samples obtained from Greece (Crete) over three consecutive harvest years.ResultsThe Raman technique and orthogonal partial least square‐discriminant analysis (OPLS‐DA) model successfully discriminated high‐ and low‐quality conventional olive oil samples for the 2017–2018 harvest year. Additionally, both organic and conventional olive oil samples were studied and distinct discrimination was achieved using OPLS‐DA on the Raman spectroscopic data for the samples with different cultivation characteristics. The combination of Raman data and statistical models for the classification of organic and conventional olive oils into high and low, and high and medium quality for the 2018–2019 and 2019–2020 harvest years, respectively, yielded satisfactory results. The samples were previously evaluated by a certified tasting panel.ConclusionsThese findings demonstrate that Raman spectroscopy, combined with multivariate statistical analysis, can serve as a complementary alternative to traditional analytical methods for the analysis of olive oils. The technique is rapid, low‐cost, and without sample pretreatment.
Structure and characterization of Tremella fuciformis polysaccharides/whey protein isolate nanoparticles for sustained release of curcumin
Authors: Shang Jiaqi , Liu Yang , Kang Jiaxin , Yang Shen , Jin Ritian 
Published: September 2023

AbstractBACKGROUNDWhey protein isolate (WPI) nanoparticles can be used in a strategy to improve the bioavailability of curcumin (CUR) although they are generally not stable. Previous studies have indicated that Tremella fuciformis polysaccharides (TFPs) can increase the stability of WPI. This work investigated systematically the characterization and structure of TFP/WPI nanoparticles with differing CUR content.RESULTSThe highest encapsulation efficiency of CUR was 98.8% and the highest loading content was 47.88%. The TFP‐WPI‐CUR with 20 mg mL−1 of CUR had the largest particle size (653.67 ± 21.50 nm) and lowest zeta potential (−38.97 ± 2.51 mV), and the capacity to retain stability across a variety of salt ion and pH conditions for 21 days. According to the findings of the structural analysis, the addition of TFPs and CUR rendered the structure of WPI amorphous, and the β‐sheet was reduced. Finally, in vitro release indicated that the TFP‐WPI‐CUR combination could regulate the sustained release behavior of CUR.CONCLUSIONIn summary, TFP‐WPI nanoparticles can be used as carriers for the delivery of CUR, and can expand applications of CUR in the functional food, dietary supplement, pharmaceutical, and beverage industries. © 2023 Society of Chemical Industry.
A Fibrin‐Based Human Multicellular Gingival 3D Model Provides Biomimicry and Enables Long‐Term In Vitro Studies
Authors: Sahle Maike , Wachendörfer Mattis , Palkowitz Alena L. , Nasehi Ramin , Aveic Sanja , Fischer Horst 
Published: September 2023

AbstractCollagen‐type I gels are widely used for the fabrication of 3D in vitro gingival models. Unfortunately, their long‐term stability is low, which limits the variety of in vitro applications. To overcome this problem and achieve better hydrolytic stability of 3D gingival models, fibrin‐based hydrogel blends with increased long‐term stability in vitro are investigated. Two different fibrin‐based hydrogels are tested: fibrin 2.5% (w/v) and fibrin 1% (w/v)/gelatin 5% (w/v). Appropriate numbers of primary human gingival fibroblasts (HGFs) and OKG4/bmi1/TERT (OKG) keratinocytes are optimized to achieve a homogeneous distribution of cells under the assumed 3D conditions. Both hydrogels support the viability of HGFs and the stability of the hydrogel over 28 days. In vitro cultivation at the air–liquid interface triggers keratinization of the epithelium and increases its thickness, allowing the formation of multiple tissue‐like layers. The presence of HGFs in the hydrogel further enhances epithelial differentiation. In conclusion, a fibrin‐based 3D gingival model mimics the histology of native gingiva in vitro and ensures its long‐term stability in comparison with the previously reported collagen paralogs. These results open new perspectives for extending the period within which specific biological or pathological conditions of artificial gingival tissue can be evaluated.
A compact VHF/UHF band quasi‐Yagi antenna for multifunction radar applications
Authors: Kim Sungpeel , Han Junyong , Jang Younhui , Choi Jaehoon 
Published: September 2023

AbstractA compact quasi‐yagi antenna for multifunction radar applications is proposed, consisting of a dual dipole‐driven element, a half bow‐tie reflector and a bow‐tie director. Size reduction is achieved by adding the half bow‐tie reflector structure. Addition of the half bow‐tie reflector and bow‐tie director improves the gain and front‐to‐back ratio in the Very high frequency (VHF)/Ultra high frequency (UHF) band. The measured −10 dB reflection coefficient bandwidths fully cover the VHF and UHF bands. The measured gain and front‐to‐back ratio (FBR) at 226.5 MHz are 5.63 dBi and 9.39 dB, respectively. The measured gain and FBR at 435 MHz are 5.79 dBi and 9.13 dB, respectively. Therefore, the proposed antenna is suitable for VHF/UHF band multifunction radar applications.
A low‐profile four‐element MIMO antenna array with new decoupling structures
Authors: Zhou Xiangyu , Zhai Huiqing , Xi Lei , Wei Zichun , Ma Shaobo , Zheng Licheng 
Published: September 2023

AbstractA low‐profile four‐element multiple‐input multiple‐output (MIMO) antenna array with new decoupling structures is proposed in this letter. The presented MIMO antenna array contains four parts: dual‐polarized antennas, power dividers, the AMC surface, and the new decoupling structures. The height of the dual polarized antenna is 10 mm (0.08λ0, λ0 is the wavelength propagating in free space at 2.5GHz). Meanwhile, the proposed MIMO antenna array can offer an impedance band from 2.5 GHz to 2.7 GHz. The new decoupling structures can greatly improve the isolation of each port in the four‐element MIMO antenna array. Comparing with the tested results and the simulated results, they are relatively consistent.
Cascaded suspended substrate stripline bandpass filter
Authors: Alaqil Hassan , Hong Jiasheng 
Published: September 2023

AbstractA new design of bandpass filter on a single layer implemented by using high Q suspended substrate stripline (SSS) structure is proposed. The designed filter is composed of cascaded highpass (HPF) and lowpass (LPF) filters, which forms a passband with a fractional bandwidth of 21.4% centered at 1.58 GHz and exhibits a very good selectivity through two transmission zeros. The simulated and measured results show a good agreement over the bandwidth with the in‐band insertion and return losses of 0.31 dB and 17.7 dB, respectively.
Efficient RF energy harvest with a novel broadband Vivaldi rectenna
Authors: Shi Yanyan , Jing Jianwei , Fan Yue , Yang Lan , Pang Jiafei , Wang Meng 
Published: September 2023

AbstractIn this article, a compact broadband rectifying antenna (rectenna) is proposed to harvest RF energy. A novel Vivaldi antenna is presented and an efficient rectifier with a single stub matching network is designed. Simulation and experiment have been performed and a good convergence is observed between the simulated and measured results. The experimental results show that the antenna features a broad bandwidth from 2.3 GHz to 2.85 GHz and the maximum conversion efficiency of the rectifier is up to 68% at 0 dBm. The maximum conversion efficiency and output voltage of the proposed rectenna are 58% and 1.6 V at 2.45 GHz under the input power of 0 dBm.
Research on dichotomous optical current sensing technology
Authors: Shen Yan , Ge Jin‐ming 
Published: September 2023

AbstractExisting optical current transformers (OCTs) have a low measurement accuracy, weak anti‐interference capability, and poor stability during long‐term operation. To address these problems, this paper proposes a dichotomous OCT unit. First, the structure of the unit is proposed, based on a mathematical model, and current measurement methods are presented. Then, a parameter optimization scheme for the shunt frame in the dichotomous OCT units is obtained by analyzing the proposed mathematical model, and a high‐accuracy measurement method is presented for reducing the influence of external magnetic field interferences. The simulation and experimental results show that the dichotomous OCT unit has a high measurement accuracy and strong resistance against external magnetic field interference.
Compact monopole with a band‐stop matching circuit for LTE/WWAN smartphone
Authors: Shen Dong‐Lin , Zhang Li , Weng Zi‐Bin , Chen Chu‐Hui , Jiao Yong‐Chang 
Published: September 2023

AbstractAn LTE/WWAN monopole antenna with a compact size of 12.5 × 28.7 mm2 for smartphone applications is designed. The antenna is formed by an L‐shape driven branch, a parasitic shorting branch, and a band‐stop matching circuit. By capacitive coupling and loading a matching circuit, the antenna generates four resonant modes in the working bands. The band‐stop matching circuit is applied to enlarge the bandwidth of the low working band. The measured −6 dB impedance bandwidth of the presented antenna ranges from 683 MHz to 962 MHz and from 1632 MHz to 2710 MHz, covering LTE/WWAN eight‐band operation. Acceptable radiation performances are achieved over the working bands. The measured efficiencies are 45.4%‐61.2% and 44.5%‐66.4% and the measured gains are −0.6 dBi‐2.0 dBi and 0.07 dBi‐2.69 dBi in the low and high working band, respectively.
Electrically small inverted L planar patch antenna for wireless application
Authors: Patel Riki H , Upadhyaya Trushit , Desai Arpan 
Published: September 2023

AbstractThis paper presents a miniature structure using a printed board facilitating single band operation for WLAN application. The two inverted L groove structures are used as additional resonators to produce a single band operation for covering the WLAN frequency band of 2.4 GHz (2.4‐2.484 GHz) and peak gain is 10.42 dbi. Presented return loss and radiation pattern of proposed antenna with comparisons simulated and measured results by fabricating the antenna.
Rectangular dielectric resonator antenna fed by offset tapered copper and graphene microstrip lines for 5G communications
Authors: Xia Wei , Zhang Bohan , Zhou Wenqing , Zhang Jingwei , Liu Chengguo , He Daping , Wu Zhi Peng 
Published: September 2023

AbstractIn this paper, rectangular dielectric resonator antennas (RDRAs) fed by offset tapered copper and graphene microstrip lines are presented. A comparison between these two feeding materials is made with an aim of using the high‐conductivity graphene film (HCGF) to replace copper for feeding the RDRA if feasible. Four feed forms have been discussed. The presented feed mechanism is able to couple electromagnetic energy in three different modes of the RDRA. The HCGF is utilized to replace copper for feeding the RDRA. An impedance bandwidth of 11.32% (3.25 GHz ~ 3.64 GHz) is realized in the experiments by using a graphene feed line, compared to that of 12.24% (3.22 GHz ~ 3.64 GHz) for copper, and a peak gain of 4.48dBi is obtained at the center frequency. The results show that the HCGF can be used to couple the RDRA, and the HCGF fed RDRA has good performance. Radiation patterns around the center frequency are also presented.
A novel analytic design method of dual‐band harmonic‐tuned power amplifiers
Authors: Huang Hang , Zhang Bo , Yu Cuiping , Gao Jinchun , Wu Yongle , Liu Yuanan 
Published: September 2023

AbstractIn this paper, an analytic methodology for designing output‐matching network (OMN) is presented. The proposed OMN integrates harmonic control circuit and reduces the complexities of design and circuit structure. Besides, the second and third harmonics control are provided for two operated frequencies. In order to verify the method, a 1.8/2.65 GHz dual‐band high‐efficiency PA adopting a GaN HEMT is presented. Experimental results show the drain efficiencies of 76.2% and 71.6%, output power of 43 and 42.7 dBm at 1.8 and 2.65 GHz, respectively. In addition, the drain efficiency more than 65% can be maintained from 1.55‐2.0 GHz and 2.65‐2.8 GHz.
Origin of interference fringes and its countermeasures in coherent terahertz imaging
Authors: Ning Wei , Qi Feng , Liu Zhaoyang , Wang Yelong , Wang Jinkuan 
Published: September 2023

AbstractInterference fringes are quite common in coherent imaging systems. As a kind of waves, terahertz (THz) light has such a phenomenon inherently when multiple reflections happen in focal plane imaging systems, which generally includes several mirrors. In this paper, we will demonstrate the fringe pattern in a typical reflective imaging system, which is similar to the “Newton Ring” phenomenon as in optics. The good point is that it might be helpful to measure the gesture of the object, while it is quite annoying in imaging since important information is hidden behind the fringes and we could even not recognize the object. To obtain a decent image, we propose three methods via tuning the frequency and location of the objects, also we can tune the illumination angle of THz waves.
An 4.7 GHz low‐power cross‐coupled GaN HEMT oscillator
Authors: Jang Sheng‐Lyang , Su Yen‐Jung , Lin Ke Jen , Wang Bing‐Jie 
Published: September 2023

AbstractA GaN HEMT oscillator implemented with the WIN 0.25 μm GaN HEMT technology is designed. The oscillator consists of two HEMT amplifiers with cross‐coupled feedback topology. With the supply voltage of VDD = 0.4 V, the GaN VCO current and power consumption of the oscillator are 6.673 mA and 2.669 mW, respectively. The oscillator can generate differential signal at 4.7 GHz and it also supplies output power − 5.3 dBm. At 1 MHz frequency offset from the carrier the phase noise is −121.77 dBc/Hz. The die area of the GaN HEMT oscillator is 2 × 1 mm2.
Low‐profile broadband dual‐polarized antenna utilizing metasurface
Authors: Ta Son Xuat , Nguyen Minh Duc , Nguyen Thi Hai‐Yen , Nguyen Truong Khang , Nguyen Khac Kiem , Dao Ngoc Chien 
Published: September 2023

AbstractA dual linearly polarized antenna with a low profile and significantly enhanced operating bandwidth is proposed. The primary radiating elements are two conventional loop dipoles fed orthogonally by two printed baluns with wideband and high isolation characteristics. The operating bandwidth is further improved by utilizing a metasurface inserted between the radiators and a shallow cavity reflector. This does not only lower the structure profile but also considerably improves the antenna gain. The final prototype with an overall size of 150 mm × 150 mm × 15 mm (0.83λ × 0.83λ × 0.083λ at the lowest operating frequency of 1.66 GHz) has been realized and experimentally validated. The measurements resulted in a −10‐dB impedance bandwidth covering a frequency range from 1.66 GHz to 2.80 GHz (51.1%) for both ports with an isolation of higher than 30 dB across the entire band. In addition, at both ports, the antenna achieves a gain of greater than 8.7 dBi and a radiation efficiency greater than 80% across the operating bandwidth.
Wideband bandstop filter using an SIR based interdigital capacitor
Authors: Kim Changsoon , Shrestha Bhanu , Son Kwang Chul 
Published: September 2023

AbstractIn this article, a microstrip wideband bandstop filter (W‐BSF) with a stepped impedance resonator (SIR)‐based interdigital capacitor (IDC) is proposed. By using an SIR‐based symmetric IDC, a wide rejection of bandwidth of 4.27 GHz at the center frequency of 5.85 GHz can be achieved. The insertion loss (S21) and return loss (S11) were 17.89 dB and 0.22 dB at 5.85 GHz, respectively, in the measurement results, which also verified that the bandwidth can be widely tuned by increasing the length, d from the main transmission line to the SIR‐based symmetric IDC section. As a result, we achieved practically applicable simulated and measured S‐parameter responses. The overall dimension of the optimized W‐BSF was (13.80 × 10.98) mm2.
Characterization of multiple‐input‐multiple‐output antennas under different multipath environments in a reverberation chamber
Authors: Nguyen Tien Manh , Kim Seung‐Ho , Chung Jae‐Young 
Published: September 2023

AbstractMultiple‐input‐multiple‐output (MIMO) antennas with different envelope correlation coefficients (ECCs) were designed and characterized in a reverberation chamber (RC) under different fading channels: urban macro, urban micro, and Rayleigh. The generation of different multipath environments and the procedures to estimate MIMO antenna figures of merit are described in detail. The experiment results show the MIMO antenna radiation efficiency remains unchanged as the multipath environment changes. In contrast to the radiation efficiency, ECC has discrepancies between the fading channels, indicating the effect of operating environments on MIMO antenna performance.
Enhancement of the antenna bandwidth by coupling the planar inverted‐F antenna and multi‐ultra‐thin slots for handheld devices with metal housing
Authors: Lee Chih‐Hung , Lin Ding Bing , Lu Guan‐Hung 
Published: September 2023

AbstractWe propose an invisible multi‐ultra‐thin slot antenna and a planar inverted‐F antenna (PIFA) coupling design for handheld mobile devices in complete metal housing systems. To enhance the bandwidth of the traditional single λ/4 PIFA used in a 2.45‐GHz Wi‐Fi system and to consider the strong impact on radiation due to the metal‐housing shielding effect and position of the internal antenna, this design etches 0.1‐mm wide slots on the metal housing using PIFA to excite these slot antennas through coupling. The metal housing is a major radiator that enhances the antenna bandwidth and efficiency. It uses electric and magnetic coupling between the two antennas to achieve the specification bandwidth, and we design the number, gap, and position of slots by investigating the mutual coupling effect. The bandwidth of the proposed structure is 147 and 134 MHz in simulations and in measurements involving the etching of three multi‐ultra‐thin slots, respectively (L = 38 mm, W = 0.1 mm), for 2.45‐GHz usage. The results depict that this design enhances the antenna bandwidth when some slots are etched, especially for handheld devices with metal housing.
High isolation and high linearity double‐pole double‐throw CMOS switch matrix for Ka‐band wireless transceiver front‐end IC
Authors: Park Sangyong , Lee Jeong‐Yun , Kim Jeong‐Geun , Baek Donghyun 
Published: September 2023

AbstractThis letter proposes a double‐pole double‐throw (DPDT) switch with high isolation and high linearity using a 65‐nm CMOS process. To improve the isolation, resonant inductors are employed for the core switches, which are composed of a single‐stacked NMOS with gate‐body floating techniques. And, the switch is controlled by a cross‐biasing technique to increment the power linearity. The active circuits are designed separately from the passive elements to reduce the interference. The core area of the proposed switch excluding all of the pads is 380 × 300 μm2. The minimum insertion loss is 2.57 dB at 23 GHz and maximum isolation is 39.7 dB at 26 GHz, respectively. The third‐order intermodulation intercept point (IIP3) is 37 dBm at 28 GHz.
Multiband bandpass filter design using E‐plane septa for waveguide application
Authors: Li Xiaokun , Zhang Yonghong , Da Xu Kai , Wang Junfeng , Li Shudan , Fan Yong 
Published: September 2023

AbstractMultiband bandpass filter (BPF) design is proposed by utilizing E‐plane septa to introduce transmission zeros in‐band for waveguide application. Due to the unique employment of E‐plane septa, multiband BPF responses are flexible to realize. Since number of transmission zeros is strongly dependent on the structure of employed septa, by adjusting the parameters of septa, dual‐band, tri‐band, and quad‐band, multiband BPF responses are presented. While various multiband responses can be achieved without changing the structure, it is more competitive and compatible. Somehow, tri‐band and quad‐band W‐band filters are fabricated for validation of the design technique for multiband BPF applications.
Dual‐band filtering antenna using dual‐mode patch resonators
Authors: Ogbodo Eugene A. , Aly Mostafa G. , Ali Amira El‐Tokhy , Wu Yun , Wang Yi 
Published: September 2023

AbstractThis paper proposes the integration of a dual‐band bandpass filter and antenna using a filter synthesis method. A dual‐mode perturbed patch resonator and a dual‐mode patch antenna are used in the implementation. The two patches are placed back‐to‐back to share a common ground. To increase the degree of freedom in controlling the channel bandwidths and to avoid radiation interference, a slot coupling technique is used to couple both patches. The patch resonator performs the signal splitting and combining function while the patch antenna contributes to the filtering poles and performs the radiating function. Good agreements have been achieved between the measurements of the prototype device and the simulations.