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全固态中波发射机射频功率放大器原理与维护

The centrosymmetric to non-centrosymmetric transformation induced by alkaline-earth cations producing infrared nonlinear optical AeMngaS（Ae = Ca, Sr）

中国科技纵横 2024年第8期 91-93页

作者：卓嘎西藏自治区广播电视局定日中波转播台西藏日喀则 858299

本文对全固态中波发射机射频功率放大器进行了深入研究,概述全固态中波发射机的基本工作原理,分析射频功率放大器的设计要点和优化方法、常见故障的诊断与排除方法,阐述该领域目前的研究进展,并针对当前存在的主要问题与挑战,比如高温... 详细信息

本文对全固态中波发射机射频功率放大器进行了深入研究,概述全固态中波发射机的基本工作原理,分析射频功率放大器的设计要点和优化方法、常见故障的诊断与排除方法,阐述该领域目前的研究进展,并针对当前存在的主要问题与挑战,比如高温效应、射频干扰与抗干扰性、尺寸和重量等进行详细分析.在此基础上,提出了全固态中波发射机射频功率放大器的未来发展方向和建议,以期为该领域的研究和应用提供参考和借鉴.

关键词：全固态中波发射机射频功率放大器研究进展挑战发展方向

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Science China Chemistry 2024年

作者： Yang-Ping Zhang Shao-Min Pei Wen-fa Chen Bin-Wen Liu Xiao-Ming Jiang Guo-Cong Guo State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter Chinese Academy of Sciences School of Physical Science and Technology Shanghai Tech University Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China

Non-centrosymmetric （NCS） structure is an indispensable prerequisite for second-order nonlinear optical （NLO） ***,the mainstream approach for designing new NCS structures still relies on chemical substitution,necessitating an urgent infusion of fresh *** this work,two isomorphic sulfides AeMn6ga6S16（Ae=Ca,1;Sr,2） are afforded by modifying the skeleton of centrosymmetric （CS） Mn2ga2S5via introducing strong electropositive alkaline-earth ***,the incorporation of Ca2+/Sr2+cations allows the elementary[MngaS9]∞chains to reconfigure into bumpy[MnS6]-[gaS4]layers in a new engagement manner,thus enabling the conversion from CS to NCS *** modifications cause not only strong second-harmonic generation （SHG） responses （～1.5×benchmark AggaS2@1,700 nm）,but also significantly feasible bandgaps（2.60–2.64 e V） compared to the sulfide Mn2ga2S5（1.36 eV）,which ultimately facilitate ultrahigh laser-induced damage thresholds （4.4–6.6×AggaS2@1,064 nm for compounds 1 and 2）.The present study offers an ingenious approach for the transformation of CS to NCS structure.

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Accidental Ingestion of Nitric Acid in an Agricultural Company: A Case Study and Literature Review

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Occupational Diseases and Environmental Medicine 2024年第1期12卷 21-27页

作者： Asséga Sylvain Sagna Mame Thioro Aïssatou fall Mossane Dominique Ndour Sidy Diallo Société de Cultures Légumières (SCL) Saint-Louis Sénégal West Africa farms (WAF) Yamane Louga Sénégal International Committee of The Red Cross Dakar Sénégal Saint-Louis Regional Hospital Center Saint-Louis Sénégal

Introduction: Though common in society, caustic accidental ingestion is rare in the agricultural industry. This study describes a case of ingestion of nitric acid used as an agricultural fertilizer by an ordinary worker at the Société de Cultures Légumières. Clinical Case: This is a 33-year-old unschooled woman who ingested a sip of nitric acid from an abandoned labelled acid canister near a farming plot of land. She showed a burn of the oral cavity with a bleeding tablecloth and an intense retrosternal pain. The duodenal oesophagus fibroscopy screening that was carried out 18 hours after the accident, revealed an esophagitis class 2b. The tests revealed no anomalies. Fifteen (15) days after the accident, the FOGD was normal. Following an 8-month-follow up, no signs of stenosis or degeneration were noted. Conclusion: The accidental ingestion of nitric acid is rare in adult. Its treatment is mainly symptomatic and aims at preserving vital functions without directly fighting the ingested substance off. The right actions must be integrated into the 15-minute Health and Safety awarenesssessions for optimum pre-hospital management. The hospital evaluation is mandatory and is carried out thanks to the digestive endoscopy, which is still relevant in this indication, but is completed by the thoraco-abdominal CT. The latter is very sensitive the transmural necrosis diagnosis.

关键词： Accident Agriculture Caustic Fibroscopy Senegal

Trends in colorectal cancer incidence according to an increase in the number of colonoscopy cases in Korea

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World Journal of gastrointestinal Oncology 2024年第1期16卷 51-60页

作者： ga Hee Kim Yeong Chan Lee Tae Jun Kim Sung Noh Hong Dong Kyung Chang Young-Ho Kim Dong-Hoon Yang Chang Mo Moon Kyunga Kim Hyun Gun Kim Eun-Ran Kim Division of gastroenterology Department of Internal MedicineAsan Medical CenterUniversity of Ulsan College of MedicineSeoul 05505South Korea Department of Digital Health Samsung Advanced Institute for Health Science and TechnologySungkyunkwan University School of MedicineSeoul 06351South Korea Division of gastroenterology Department of Internal MedicineSamsung Medical CenterSungkyunkwan University School of MedicineSeoul 06351South Korea Division of gastroenterology Department of Internal MedicineEwha Womans UniversitySeoul 07985South Korea Biomedical Statistics Center Samsung Medical CenterSeoul 06351South Korea Division of gastroenterology Department of Internal MedicineSoonchunhyang University College of MedicineSeoul 04401South Korea

BACKGROUND The incidence of colorectal cancer(CRC)and preinvasive CRC(e.g.,early colon cancer and advanced adenoma)is gradually increasing in several *** To evaluate the trend in incidence of CRC and preinvasive CRC according to the increase in the number of colonoscopies performed in *** This retrospective cohort study enrolled Korean patients from 2002 to 2020 to evaluate the incidence of CRC and preinvasive CRC,and assess the numbers of diagnostic colonoscopies and colonoscopic ***-related complications by age group were also *** The incidence of CRC showed a rapid increase,then decreased after 2012 in the 50-75 year-age *** the study period,the rate of incidence of preinvasive CRC increased at a similar level in patients under 50 and 50-75 years of *** 2009,the increase has been rapid,showing a pattern similar to the increase in *** rate of colonoscopic polypectomy in patients aged under 50 was similar to the rate in patients over 75 years of age after *** rate of complications after colonoscopy and related deaths within 3 mo was high for those over 75 years of *** The diagnosis of preinvasive CRC increased with the increase in the number of colonoscopies *** the risk of colonoscopy-related hospitalization and death is high in the elderly,if early lesions at risk of developing CRC are diagnosed and treated under or at the age of 75,colonoscopy-related complications can be reduced for those aged 76 years or over.

关键词： Colorectal cancer Preinvasive colorectal cancer Colorectal polypectomy Colonoscopy

土工织物加固土质坝堤加高工程的离心模型试验研究

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岩土工程学报 2024年第S1期46卷 112-116页

作者：李笑琳张嘎清华大学水利水电工程系北京100084

土工织物是一种广泛用于边坡加固的合成材料,但土工织物在土质坝堤加高工程中尚未得到合理应用。针对水位变动条件下土工织物加固的加高土质坝堤进行了离心模型试验,观测了加高坝堤的变形破坏响应过程。试验结果表明,土工织物加固的加... 详细信息

土工织物是一种广泛用于边坡加固的合成材料,但土工织物在土质坝堤加高工程中尚未得到合理应用。针对水位变动条件下土工织物加固的加高土质坝堤进行了离心模型试验,观测了加高坝堤的变形破坏响应过程。试验结果表明,土工织物加固的加高土质坝堤的破坏呈现出新旧坝堤各异的特点,新旧坝堤呈现出不同的破坏特性,离土工织物较远的旧坝堤先发生破坏,土工织物加固的新坝堤的破坏发生较晚,且呈现从上到下渐进发展的特性;加高坝堤的最终破坏是由变形局部化和局部破坏相互耦合渐进发展导致的;土工织物分为加固段和约束段,在约束段坝堤给土工织物提供约束力,在加固段土工织物限制了坝堤的变形,土工织物的加固机理是将坝堤深部的约束力传递到坝堤表面,从而增强了坝堤浅层的抗滑能力;水位变动引起坝堤的变形增加,土工织物的加固作用也随之增强。

关键词：坝堤加高土工织物离心模型试验水位变动

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囊玛艺术新论

西藏研究 2024年第3期 66-76,M0005,M0006页

作者：觉嘎洛金宝西藏大学艺术学院拉萨850000

囊玛是一种集歌、舞、乐为一体的西藏传统表演艺术,而囊玛吉度是以囊玛艺术的实践为主要业务的行会组织。作为群众自发形成的社团组织,囊玛吉度形成背景和艺人来源具有多元化,其使用的乐器和表演的典目具有多样性。囊玛的表现内容主要... 详细信息

囊玛是一种集歌、舞、乐为一体的西藏传统表演艺术,而囊玛吉度是以囊玛艺术的实践为主要业务的行会组织。作为群众自发形成的社团组织,囊玛吉度形成背景和艺人来源具有多元化,其使用的乐器和表演的典目具有多样性。囊玛的表现内容主要包括爱情、时事、祈愿、赞颂、讽刺等内容,大多与不同时期的社会生活、观念意识等关联密切。在囊玛曲目中,有部分歌词采用了仓央嘉措的诗作,汉文关联表达和双关语也得到了广泛运用。

关键词：传统音乐囊玛囊玛吉度曲目

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数字流域模型淤地坝模块改进及减水减沙效益评估

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应用基础与工程科学学报 2024年第2期32卷 301-313页

作者：张玍傅旭东孙凯王晨沣清华大学水沙科学与水利水电工程国家重点实验室北京100084

淤地坝具有重要的水土保持作用,但其减水减沙效益的科学评估仍存在困难.一方面,淤地坝减水减沙的物理机制仍难以刻画;另一方面,观测资料有限且难以获取.以概化淤地坝卧管及溢洪道等部分的泄流机制及整体水沙调控机制为基础,改进和检验... 详细信息

淤地坝具有重要的水土保持作用,但其减水减沙效益的科学评估仍存在困难.一方面,淤地坝减水减沙的物理机制仍难以刻画;另一方面,观测资料有限且难以获取.以概化淤地坝卧管及溢洪道等部分的泄流机制及整体水沙调控机制为基础,改进和检验了数字流域模型的淤地坝模块,应用改进后的模型模拟皇甫川流域水沙过程并评估淤地坝减水减沙效益.研究结果表明:不考虑淤地坝的情况下,模型对淤地坝数量较少的近似自然状态期(1979~1986年)适用性较好,而对淤地坝数量较多的受扰状态期(2007~2012年)适用性较差,水沙模拟值明显高于实测值.考虑淤地坝的物理机制后,与原模型相比,除个别年份外,改进后的模型对受扰状态期水沙过程的模拟精度具有明显的提高,其逐日流量NSE(Nash-Sutcliffe效率系数)从-51.085~0.450提高到0.134~0.802,逐日输沙率NSE从-56.740~0.390提高到0.066~0.857.使用改进后的模型计算得受扰状态期淤地坝平均拦水量为0.142×10^(8)m^(3),减水效益为40.9%;平均拦沙量为0.050×10^(8)t,减沙效益为50.3%.研究成果可为认识淤地坝调控水沙物理机制提供模型支撑和为淤地坝建设规划提供科学指导.

关键词：淤地坝减水减沙减水减沙效益水土保持数字流域模型分布式水沙模型皇甫川

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Assessment of the Level of Knowledge about Chronic Renal failure in 271 Hypertensive Patients in Brazzaville

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Open Journal of Nephrology 2024年第1期14卷 25-36页

作者： Daniel Tony Eyeni Sinomono Ange Niama gaël Honal Mahoungou Éric gandzali-Ngabé Ndinga Berline Ngoma Precieux Dalia Mboungo Richard Loumingo Department of Nephrology University Hospital Center Faculty of Health Sciences Marien Ngouabi University Brazzaville Congo Department of Public Health Faculty of Health Sciences Marien Ngouabi University Brazzaville Congo

Background and Objectives: Chronic kidney disease (CKD) is now a global public health problem. In low- and middle-income countries such as the Congo, access to dialysis is low and inequitable. The prevention of CKD involves raising awareness among patients at risk, such as those suffering from arterial hypertension (AH), by improving their knowledge of CKD. The objectives of our work were to determine the level of knowledge about CKD among hypertensive patients and to identify the factors associated with a low level of knowledge. Methodology: We conducted a 3-month descriptive and analytical cross-sectional study from 1 August to 30 October 2023 in 3 large public hospitals in Brazzaville (capital of the Republic of Congo). We included: hypertensive patients aged 18 and over who had freely consented to participate in our study and were able to answer the questions on the survey form. Patients with known hypertension who had been followed for less than 3 years and those with known chronic renal failure were not included. Results: The mean age was 58.4 ± 14.4 years (29 - 88 years). There were 121 men and 150 women (sex ratio = 0.8). All the patients were educated;37.2% with a higher level of education and 13.6% with primary education. 24 patients (9%) had a good level of knowledge about CKD and 153 (56%) had poor knowledge. A good level of knowledge was associated with the duration of hypertension, intellectual level and the existence of associated heart disease. Conclusion: Our study reveals a significant lack of knowledge about chronic kidney disease among hypertensive patients in Brazzaville.

关键词： Knowledge Chronic Renal failure Hypertensives Brazzaville

Multivariate Approach to Characterizing Soil Quality of gabonese’s Ferralitic Soils

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Open Journal of Soil Science 2024年第4期14卷 237-268页

作者： Neil-Yohan Musadji Rolf gaël Mabicka Obame Michel Mbina Mounguengui Jean Aubin Ondo Lydie-Stella Koutika Eric Ravire Claude Geffroy Laboratoire De Chimie Des Milieux et Des Mat&#233riaux Inorganiques Laboratoire D&#8217Analyse Des Sols et Environnement D&#233partement Des Sciences Fondamentales De L&#8217Ing&#233nieur Institut National D&#8217Agronomie et De Biotechnologies Universit&#233 Des Sciences et Techniques De Masuku Franceville Gabon Institut De Chimie Des Milieux et Maté riaux De Poitiers (IC2MP) Universit&#233 De Poitiers Poitiers France Laboratoire De Chimie Des Milieux et Des Mat&#233riaux Inorganiques Laboratoire D&#8217Analyse Des Sols et Environnement D&#233partement De Phytotechnologie Institut National D&#8217Agronomie et De Biotechnologies Universit&#233 Des Sciences et Techniques De Masuku Franceville Gabon Dé partement De G&#233ologie Facult&#233 Des Sciences Universit&#233 Des Sciences et Techniques De Masuku Franceville Gabon Laboratoire Pluridisciplinaire Des Sciences Ecole Normale Sup&#233rieure Libreville Gabon Centre De Recherche Sur La Productivité et La Durabilit&#233 Des Plantations Industrielles Pointe Noire Republic of Congo Sucaf gabon Somdiaa Franceville Gabon

Assessing soil quality is essential for crop management and soil temporal changes. The present study aims to evaluate soil quality in the Ferralitic soils context countrywide. This assessment was done using multivariate soil quality indice (SQI) models, such as additive quality index (AQI), weighted quality indexes (WQIadd and WQIcom) and Nemoro quality index (NQI), applied to two approaches of indicator selection: total data set (TDS) and minimum data set (MDS). Physical and chemical soil indicators were extracted from the ORSTOM’s reports resulting from a sampling campaign in different provinces of gabon. The TDS approach shows soil quality status according to eleven soil indicators extracted from the analysis of 1,059 samples from arable soil layer (0 - 30 cm depth). The results indicated that 87% of all provinces presented a very low soil quality (Q5) whatever the model. Among soil indicators, exchangeable K+ and Mg2+, bulk density and C/N ratio were retained in MDS, using principal component analysis (PCA). In the MDS approach, 50 to 63% of provinces had low soil quality grades with AQI, WQIadd and NQI, whereas the total was observed with WQIcom. Only 25% of provinces had medium soil quality grades with AQI and NQI models, while 12.5% (NQI) and 25% (AQI) presented high quality grades. Robust statistical analyses confirmed the accuracy and validation (0.80 r P ≤ 0.016) of AQI, WQIadd and NQI into the TDS and MDS approaches. The same sensitivity index value (1.53) was obtained with AQI and WQIadd. However, WQIadd was chosen as the best SQI model, according to its high linear regression value (R2 = 0.82) between TDS and MDS. This study has important implications in decision-making on monitoring, evaluation and sustainable management of gabonese soils in a pedoclimatic context unfavorable to plant growth.

关键词： gabon Ferralitic Soil Soil Indicators Standard Score Function Soil Quality Indices Sustainable Soil Soil Management