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Angle-Based Beamforming in mmWave Massive MIMO Systems with Low Feedback Overhead Using Multi-Pattern Codebooks

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China Communications 2019年第9期16卷 18-30页

作者： Yuyan Zhao Yanan Liu Gary Boudreau akram Bin Sediq Xianbin Wang Department of Electrical and Computer Engineering Western UniversityLondonON N6A 5B9Canada Ericsson Canada OttawaON K2K 2V6Canada

The integration of millimeter-wave(mmWave)communications and massive multiple input multiple output(MIMO)techniques is a promising solution to dramatically increase the 5G network *** using large antenna arrays,beamforming can be adopted to improve the 5G capacity by employing spatial domain *** a frequency division duplexing(FDD)based 5G mmWave MIMO system,beamforming operation requires timely downlink channel state information(CSI)***,the rapid channel variations caused by short wavelength of mmWave band,and the high-level feedback information required due to the large number of antennas in massive MIMO system lead to the significantly increased beamforming *** this paper,by exploiting the higher angular stability of such channels,we propose an angle-based beamforming scheme to reduce the feedback frequency and the number of feedback *** facilitate this approach users are initially selected to reduce the intra-zone interference before ***,location related feedback,which is not affected by the number of antennas,is adopted to reduce *** simulation results show that two proposed user selection algorithms can adapt to scenarios with diverse requirements,while the feedback overhead of proposed angle-based beamforming algorithm is sharply reduce compared with that of CSIbased beamforming algorithm.

关键词： angle-based beamforming codebook feedback reduction user selection

温度对酶促聚对苯二甲酸乙二醇酯降解的影响分析

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Chinese Journal of Catalysis 2024年第5期60卷 284-293页

作者：伊科拉木·艾克然木曹宇飞邢皓丁于敬罗宇政韦韧张一飞北京化工大学化工资源有效利用国家重点实验室北京100029 北京化工大学北京软物质科学与工程高精尖创新中心北京100029 华南理工大学食品科学与工程学院应用生物催化实验室广东广州510640 格赖夫斯瓦尔德大学生物化学研究所格赖夫斯瓦尔德德国

近年来,聚对苯二甲酸乙二酯(PET)的酶法降解及循环利用备受关注.PET的酶法降解是在不可溶聚合物表面发生的界面催化过程,酶通过水解PET聚合物表面上可及的酯键,将聚合物逐渐分解成单体.反应温度可以从酶的催化活性、热稳定性以及PET材... 详细信息

近年来,聚对苯二甲酸乙二酯(PET)的酶法降解及循环利用备受关注.PET的酶法降解是在不可溶聚合物表面发生的界面催化过程,酶通过水解PET聚合物表面上可及的酯键,将聚合物逐渐分解成单体.反应温度可以从酶的催化活性、热稳定性以及PET材料的生物可降解性等多个方面影响PET的降解过程,是影响PET酶法降解效果的主要因素之一.深入了解温度对PET酶降解过程的热力学和动力学调控机制,对PET降解酶的发掘与改造和酶法降解工艺的优化具有重要意义.本文以叶枝堆肥角质酶(LCC)的突变体WCCG为例,详细研究了温度对WCCG降解低结晶度PET(结晶度7.6%)和高结晶度(结晶度30%)PET微颗粒的影响.通常认为PET的酶促降解需要在其玻璃化转变温度(Tg,~70℃)附近或以上进行.实验测定了不同温度下的降解速率,并利用阿伦尼乌斯公式作图.结果表明,当反应温度在45℃(低于通常认为的Tg,b值约20℃)附近时,反应活化能突然降低,说明此时PET微颗粒表面的玻璃化转变已经开始,酶促降解已经能够有效进行,表现出酶解PET的界面催化特征.当温度高于75℃时,PET降解速率迅速降低,酶受热失活.研究还发现,WCCG存在热激活现象:通过将WCCG在不同温度下温育一段时间后在60℃下进行活性测定,WCCG在50-70℃范围内温育后活性显著提高;在70℃下温育4 h后其降解低结晶度PET的活性提高约1倍,同时对小分子底物4-硝基苯酚丁酯的活性也有明显提高.利用圆二色光谱和荧光光谱检测了WCCG的二级和三级结构变化.结果表明,热处理后的WCCG中的α-螺旋含量显著减少而β折叠含量增加,酶分子疏水性提高,这与分子动力学模拟结果一致.单分子力谱测试结果表明,热处理后的WCCG较处理前的酶与PET薄膜之间的粘附力从88 pN提高到150 pN.因此,WCCG的热激活是其本征催化活性改善和酶与PET表面吸附力增强共同作用的结果.WCCG在高结晶度PET的降解中也存在类似热激活现象.此外,在长时间的降解反应中,无定形区域的PET链段在相对较高的降解温度下逐渐进一步结晶,导致酶催化降解速率随着降解时间的延长而下降.综上所述,温度对酶催化PET降解过程的主要影响包括:PET表面的玻璃化转变、酶的热激活、酶的热失活、温度导致的PET材料再结晶,这些因素相互交织,说明酶促PET降解的温度依赖的复杂性.未来的研究除了继续挖掘和设计高活性、高稳定的PET水解酶外,还应提高酶在45到70℃范围内的催化活性并关注降解工艺的优化.

关键词：聚对苯二甲酸乙二酯酶法降解酶的热激活活化能表面玻璃化转变

A laterally graded junctionless transistor

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Journal of Semiconductors 2014年第3期35卷 29-32页

作者： Punyasloka Bal Bahniman Ghosh Partha Mondal M.W.akram Department of Electrical Engineering Indian Institute of Technology Kanpur Microelectronics Research Center 10100 Burnet Road University of Texas at Austin

This paper proposes a laterally graded junctionless transistor taking peak doping concentration near the source and drain region, and a gradual decrease in doping concentration towards the center of the channel to improve the I OFF and I ON/I OFF ratio. The decrease of doping concentration in the lateral direction of the channel region depletes a greater number of charge carriers compared to the uniformly doped channel in the OFF-state,which in turn suppresses the OFF state current flowing through the device without greatly affecting the ON state current.

关键词： junctionless field effect transistor laterally graded subthreshold slope

Computer Decision Support System for Skin Cancer Localization and Classification

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Computers, Materials & Continua 2021年第7期68卷 1041-1064页

作者： Muhammad Attique Khan Tallha akram Muhammad Sharif Seifedine Kadry Yunyoung Nam Department of Computer Science COMSATS University IslamabadWah Campus47040Pakistan Department of Computer and Electrical Engineering COMSATS University IslamabadWah Campus47040Pakistan Department of Mathematics Beirut Arab UniversityBeirutLebanon Department of Computer Science and Engineering Soonchunhyang UniversityAsanKorea

In this work,we propose a new,fully automated system for multiclass skin lesion localization and classification using deep *** main challenge is to address the problem of imbalanced data classes,found in HAM10000,ISBI2018,and ISBI2019 ***,we consider a pretrained deep neural network model,DarkeNet19,and fine-tune the parameters of third convolutional layer to generate the image *** the visualized images are fused using a High-Frequency approach along with Multilayered Feed-Forward Neural Network(HFaFFNN).The resultant image is further enhanced by employing a log-opening based activation function to generate a localized binary ***,two pre-trained deep models,Darknet-53 and NasNet-mobile,are employed and fine-tuned according to the selected *** concept of transfer learning is later explored to train both models,where the input feed is the generated localized lesion *** the subsequent step,the extracted features are fused using parallel max entropy correlation(PMEC)*** avoid the problem of overfitting and to select the most discriminant feature information,we implement a hybrid optimization algorithm called entropy-kurtosis controlled whale optimization(EKWO)*** selected features are finally passed to the softmax classifier for the final *** datasets are used for the experimental process,such as HAM10000,ISBI2018,and ISBI2019 to achieve an accuracy of 95.8%,97.1%,and 85.35%,respectively.

关键词： Skin cancer convolutional neural network lesion localization transfer learning features fusion features optimization

A classification of genes involved in normal and delayed male puberty

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Asian Journal of Andrology 2023年第2期25卷 230-239页

作者： Maleeha akram Syed Shakeel Raza Rizvi Mazhar Qayyum David J Handelsman Department of Zoology Wildlife and FisheriesPir Mehr Ali Shah Arid Agriculture University RawalpindiShamsabadMurree RoadRawalpindi 46300Pakistan Andrology Laboratory The ANZAC Research InstituteHospital RoadConcordNSW 2139Australia

Puberty is a pivotal biological process that completes sexual maturation to achieve full reproductive *** is a major transformational period of life,whose timing is strongly affected by genetic makeup of the individual,along with various internal and external *** the exact mechanism for initiation of the cascade of molecular events that culminate in puberty is not yet known,the process of pubertal onset involves interaction of numerous complex signaling pathways of hypothalamopituitary-testicular(HPT)*** developed a classification of the mechanisms involved in male puberty that allowed placing many genes into physiological *** include(i)hypothalamic development during embryogenesis,(ii)synaptogenesis where gonadotropin releasing hormone(GnRH)neurons form neuronal connections with suprahypothalamic neurons,(iii)maintenance of neuron homeostasis,(iv)regulation of synthesis and secretion of GnRH,(v)appropriate receptors/proteins on neurons governing GnRH production and release,(vi)signaling molecules activated by the receptors,(vii)the synthesis and release of GnRH,(viii)the production and release of gonadotropins,(ix)testicular development,(x)synthesis and release of steroid hormones from testes,and(xi)the action of steroid hormones in downstream effector *** in components of this system during embryonic development,childhood/adolescence,or adulthood may disrupt/nullify puberty,leading to long-term male infertility and/or *** review provides a list of 598 genes involved in the development of HPT axis and classified according to this ***,this review identifies a subset of 75 genes for which genetic mutations are reported to delay or disrupt male puberty.

关键词： delayed puberty gonadotropin releasing hormone hypogonadism male puberty puberty testosterone

Formation of thiazol-2(3H)-imines by reaction of α-amino acids, aroylisothiocyanates, and α-bromoketones in an ionic liquid

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Chinese Chemical Letters 2014年第1期25卷 119-122页

作者： Ashraf S.Shahvelayati Issa Yavari akram S.Delbari Department of Chemistry Shahr-e Ray BranchIslamic Azad UniversityTehran 18155-144Iran Department of Chemistry Tarbiat Modares UniversityTehran 14115-175Iran Department of Chemistry Islamshahr BranchIslamshahr 33135-369Iran

An efficient one-pot synthesis of functionalized thiazol-2（3H）-imines by a three-component reaction between aroylisothiocyanates, α-amino acids, and α-bromoketones in an ionic liquid is described.

关键词： Aroylisothiocyanate α-Amino acidsS-Nucleophile α-BromoketonesIonic liquid

Cost and Efficiency Analysis of Steganography in the IEEE 802.11ah IoT Protocol

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Computers, Materials & Continua 2022年第8期72卷 3929-3943页

作者： akram A.Almohammedi Vladimir Shepelev Sam Darshi Mohammed Balfaqih Fayad Ghawbar Automobile Transportation Department South Ural State UniversityChelyabinsk454080Russia Electrical and Electronics Engineering Department Karabük University Karabük78050Turkey Department of Electrical Engineering Indian Institute of Technology RoparPunjab140001India Department of Computer and Network Engineering University of JeddahJeddah23218Saudi Arabia Faculty of Engineering Technology University Tun Hussein Onn MalaysiaPagoh Campus86400Malaysia

The widespread use of the Internet of Things(IoT)applications has enormously increased the danger level of data leakage and theft in IoT as data transmission occurs through a public *** a result,the security of the IoT has become a serious challenge in the field of information *** on the network is a critical tool for preventing the leakage of private information and enabling secure and encrypted *** primary purpose of steganography is to conceal sensitive information in any form of media such as audio,video,text,or photos,and securely transfer it through wireless *** this paper,we analyse the performance characteristics of one of the steganography techniques called Hidden Communication System for Corrupted Networks(HCCNETs)for hiding sensitive *** performance analysis includes the efficiency and the cost of the system in Wireless Local Area Networks(WLANs),specifically in the IEEE 802.11ah IoT *** analysis is mainly based on a two-dimensional Markov chain model in the presence of an error ***,the model considers packet arrival rate,back-off timer freezing,back-off stages,and short retry limit to ensure compliance with IEEE 802.11ah *** stresses the importance of taking these elements into consideration while modeling the efficiency and cost of the steganographic channel *** parameters often result in a high precise channel access estimation,a more accurate and efficient accuracy measurements system,efficient channel utilisation,avoidance of throughput saturation overestimation,and ensuring that no packet is served *** results demonstrate that HCCNETs is an effective approach at low cost.

关键词： IoT HCCNETs steganography markov chain model

Exploring the Advantages and Disadvantages of the China-Pakistan Free Trade Agreement

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China & World Economy 2021年第3期29卷 83-103页

作者： Mirajul Haq Javeria Saeed Muhammad akram International Institute of Islamic Economics(HIE) International Islamic University IslamabadPakistan International Institute of Islamic Economics(HIE) International Islamic University Islamabad

This paper explores whether the China-Pakistan Free Trade Agreement(FTA),which entered into ejfect in 2007,has led to advantages or disadvantages for the participating *** assesses the gains and losses associated with the agreement rigorously using two different ***,the revealed comparative advantage index is calculated for 10 commodity *** identifies the commodity groups in which the participating countries have a comparative ***,trade creation and trade diversion are estimated for overall imports and for the commodity-group level *** analysis provides useful information about the commodity groups in which a particular party to the FTA is experiencing an advantage or a *** findings of the study show that China has an advantage in producing capital-intensive goods whereas Pakistan has a comparative advantage in the production of primary and semimanufactured *** empirical findings also indicate that,overall,the formation of the bilateral free trade agreement between Pakistan and China enhances trade with member countries as well as with nonparticipating countries.

关键词： gravity model panel data revealed comparative advantage trade creation trade diversion

The role of veterinarians in the One Health approach to antimicrobial resistance perspectives in Jordan

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Animal Diseases 2022年第1期2卷 61-70页

作者： Randa Bazzi akram Alaboudi Gabor Racz Faculty of Public Health University of DebrecenDebrecenHungary Department of Pathology and Public Health Faculty of Veterinary Medicine and SurgeryJordan University of Science and Technology(Retired)Ar-RamthaJordan Department of Public Health and Epidemiology Faculty of MedicineUniversity of DebrecenDebrecenHungary.

This study aims to evaluate the role of Jordanian veterinarians in terms of their knowledge,attitudes and common practices in combating antimicrobial resistance(AMR)and summarize the registered veterinary drugs between *** study data were collected using a standardized questionnaire that focused on the knowledge,attitudes,and practices of Jordanian *** findings were analyzed descriptively;84%of the participants agreed with the statement on the definition of *** majority(95.65%)of participants agreed that AMR is a challenge for the veterinary sector in Jordan and that it should be prioritized over other zoonotic *** 69%of the participants believed that the misuse and overuse of antimicrobials by unqualified,fraudulent,or unauthorized practitioners is the primary reason for the rise of cases associated with AMR and the challenges that accompany *** most common practice among the respondents in this study was to recommend clients(e.g.,farmers and owners)to practice good animal husbandry(80.00%).The study also revealed that there was a significant difference(p=O.015)between attendance at AMR training sessions and the professional sector(private,public,and academic)of the *** study underscores the importance of implementing a continuous education program on AMR so as to enhance the all-round knowledge of veterinarians and improve their advisory *** addition,laws should be enacted to ensure that veterinarians prescribe the correct antimicrobials and to improve surveillance systems for monitoring the use of antimicrobials in veterinary medicine.

关键词： Antimicrobial resistance Veterinarian Knowledge Practices Attitudes Jordan