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Usefulness of the clip-flap method of endoscopic submucosal dissection: A randomized controlled trial 被引量:5
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作者 Hiromitsu Ban Mitsushige Sugimoto +6 位作者 Taketo Otsuka Masaki Murata Toshiro Nakata Hiroshi Hasegawa Osamu Inatomi Shigeki Bamba Akira Andoh 《World Journal of Gastroenterology》 SCIE CAS 2018年第35期4077-4085,共9页
AIM To prospectively investigate the efficacy and safety of clipflap assisted endoscopic submucosal dissection(ESD) for gastric tumors.METHODS From May 2015 to October 2016, we enrolled 104 patients with gastric cance... AIM To prospectively investigate the efficacy and safety of clipflap assisted endoscopic submucosal dissection(ESD) for gastric tumors.METHODS From May 2015 to October 2016, we enrolled 104 patients with gastric cancer or adenoma scheduled for ESD at Shiga University of Medical Science Hospital. We randomized patients into two subgroups using the minimization method based on location of the tumor(upper, middle or lower third of the stomach), tumor size(< 20 mm or > 20 mm) and ulcer status: ESD using an endoclip(the clip-flap group) and ESD without an endoclip(the conventional group). Therapeutic efficacy(procedure time) and safety(complication: Gastrointestinal bleeding and perforation) were assessed. RESULTS En bloc resection was performed in all patients. Four patients had delayed bleeding(3.8%) and two had perforation(1.9%). No significant differences in en bloc resection rate(conventional group: 100%, clip flap group: 100%), curative endoscopic resection rate(conventional group: 90.9%, clip flap group: 89.8%, P = 0.85), procedure time(conventional group: 70.8 ± 46.2 min, clip flap group: 74.7 ± 53.3 min, P = 0.69), area of resected specimen(conventional group: 884.6 ± 792.1 mm^2, clip flap group: 1006.4 ± 1004.8 mm^2, P = 0.49), delayed bleeding rate(conventional group: 5.5%, clip flap group: 2.0%, P = 0.49), or perforation rate(conventional group: 1.8%, clip flap group: 2.0%, P = 0.93) were found between the two groups. Lessexperienced endoscopists did not show any differences in procedure time between the two groups.CONCLUSION For patients with early-stage gastric tumors, the clipflap method has no advantage in efficacy or safety compared with the conventional method. 展开更多
关键词 Gastric cancer clip FLAP method Endoscopic SUBMUCOSAL dissection Procedure time Complication Randomized clinical trial
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Effects of dietary oil sources and fat extraction methods on apparent and standardized ileal digestibility of fat and fatty acids in growing pigs 被引量:1
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作者 Lu Wang Wenjun Gao +3 位作者 Junyan Zhou Huangwei Shi Tenghao Wang Changhua Lai 《Journal of Animal Science and Biotechnology》 SCIE CAS CSCD 2023年第2期760-770,共11页
Background:There is a lack of data for the standardized ileal digestibility(SID) of fat and fatty acids in national feed databases.In addition,it is important to specify the procedures used for fat analyses.Therefore,... Background:There is a lack of data for the standardized ileal digestibility(SID) of fat and fatty acids in national feed databases.In addition,it is important to specify the procedures used for fat analyses.Therefore,an experiment was conducted to 1) determine the apparent ileal digestibility(AID) and SID of fat and fatty acids in ten different oil sources for growing pigs and to develop prediction equations for SID of fat based on fatty acid composition;and 2) compare the effect of the fat extraction methods on the calculated values for endogenous loss and digestibility of fat.Methods:Twenty-two barrows(initial body weight:32.1 ± 2.3 kg) were surgically fitted with a T-cannula in the distal ileum,and allotted to 1 of 11 experimental diets in a 4-period Youden Square design.A fat-free diet was formulated using cornstarch,soy protein isolate and sucrose.Ten oil-added diets were formulated by adding 6% of dietary oil sources to the fat-free diet at the expense of cornstarch.All diets contained 26% sugar beet pulp and 0.40% chromic oxide.Results:The endogenous loss of ether extract(EE) was lower than that of acid-hydrolyzed fat(AEE;P < 0.01).There were significant differences in the AID and SID of fat and saturated fatty acids across the dietary oil sources(P < 0.05).The SID of AEE for palm oil was lower than that of sunflower oil,corn oil,canola oil,rice oil and flaxseed oil(P < 0.01).The AID and SID of fat ranged from 79.65% to 86.97% and from 91.14% to 99.18%.Although the AID of EE was greater than that of AEE(P < 0.01),there was no significant difference in SID of EE and AEE except for palm oil.The ratio of unsaturated to saturated fatty acids(U/S) had a positive correlation with SID of fat(P < 0.05),whereas C16:0 and long chain saturated fatty acids(LSFA) were significant negatively correlated with SID of fat(P < 0.01).The best-fit equation to predict SID of fat was SID AEE = 102.75-0.15 × LSFA-0.74 × C18:0-0.03 × C18:1(Adjusted coefficient of determination = 0.88,P < 0.01).Conclusions:When calculating the SID of fat,the EE content of the samples can be analyzed using the direct extraction method,whereas the acid hydrolysis procedure should be used to determine the AID of fat.Fat digestibility of dietary oils was affected by their fatty acid composition,especially by the contents of C16:0,LSFA and U/S. 展开更多
关键词 Fat extraction methods Fatty acids growing pigs Ileal digestibility Oil sources
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Methodological impact of starch determination on starch content and ileal digestibility of starch in grain legumes for growing pigs 被引量:1
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作者 Dagmar Jezierny Rainer Mosenthin +2 位作者 Nadja Sauer Klaus Schwadorf Pia Rosenfelder-Kuon 《Journal of Animal Science and Biotechnology》 SCIE CAS CSCD 2017年第2期459-466,共8页
Background: Grain legumes represent a valuable energy source in pig diets due to their high starch content. The present study was conducted to determine the content and apparent ileal digestibility(AID) of starch i... Background: Grain legumes represent a valuable energy source in pig diets due to their high starch content. The present study was conducted to determine the content and apparent ileal digestibility(AID) of starch in different grain legume cultivars for pigs by means of both a polarimetric and enzymatic method for starch determination.Methods: Three experiments were conducted with six barrows each which were fitted with ileal T-cannulas. In total, 18 diets including six different cultivars of faba beans(Vicia faba L.) and peas(Pisum sativum L.), five different cultivars of lupins(Lupinus luteus L., Lupinus angustifolius L.), and one diet with a soybean meal(SBM) were fed.Results: The starch content of faba beans and peas was greater(P &lt; 0.05) when determined polarimetrically than enzymatically(438 vs. 345 g/kg dry matter(DM) in faba beans and 509 vs. 390 g/kg DM in peas, respectively).Considerable lower starch contents were obtained in lupins and SBM, with 82 and 48 g/kg DM(analyzed polarimetrically) and &lt;1.1 and 3 g/kg DM(analyzed enzymatically), respectively. Mean values for contents of neutral detergent fiber(NDF) and acid detergent fiber(ADF) in grain legumes ranged from 111 and 79 g/kg DM in peas to248 and 207 g/kg DM in lupins, respectively. Contents of condensed tannins in the colored flowered faba bean cultivars ranged from 2.1 to 7.4 g/kg DM. The AID of starch was greater(P &lt; 0.05) in pea than in faba bean cultivars,and using the polarimetric starch determination method resulted in greater(P &lt; 0.05) digestibility values than using enzymatic starch analysis(84 vs. 80% in faba beans and 86 vs. 83% in peas). Moreover, AID of starch differed(P &lt; 0.05)within pea cultivars and starch digestibility in faba beans decreased linearly(P &lt; 0.05) as the content of condensed tannins increased. However, there was no relationship between contents of NDF and ADF and AID of starch in pea and faba bean cultivars.Conclusion: Both contents and AID of starch in grain legumes can vary as influenced by the analytical method used for starch determination. Generally, starch digestibility is greater when measured by polarimetric rather than enzymatic methods. 展开更多
关键词 Grain legumes growing pigs Ileal starch digestibility Starch determination method
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Novel robust S transform based on the clipping method
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作者 Xiumei Li Yingtuo Ju 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2013年第2期209-214,共6页
This paper presents a novel robust S transform algorithm based on the clipping method to process signals corrupted by impulsive noise.The proposed algorithm is introduced to determine the clipping threshold value acco... This paper presents a novel robust S transform algorithm based on the clipping method to process signals corrupted by impulsive noise.The proposed algorithm is introduced to determine the clipping threshold value according to the characteristics of the signal samples.Signals in various impulsive noise models are considered to illustrate that the robust S transform can achieve better performance than the standard S transform.Moreover,mean square errors for instantaneous frequency estimation of the robust S transform are compared with that of the standard S transform,showing that the robust S transform can achieve significantly improved instantaneous frequency estimation for the signals in impulsive noise. 展开更多
关键词 S transform clipping method impulsive noise mean square error(MSE)
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Efficacy of mucosa-submucosa clip closure method after gastric endoscopic submucosal dissection
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作者 Satoshi Kinoshita Toshihiro Nishizawa +4 位作者 Ai Fujimoto Hideki Mori Yoshihiro Nakazato Masahiro Kikuchi Toshio Uraoka 《World Journal of Gastrointestinal Endoscopy》 CAS 2020年第1期17-22,共6页
BACKGROUND We recently developed a new endoscopic closure technique using only conventional endo-clips for colorectal lesions.Little is known about the feasibility of the endoscopic mucosa-submucosa clip closure metho... BACKGROUND We recently developed a new endoscopic closure technique using only conventional endo-clips for colorectal lesions.Little is known about the feasibility of the endoscopic mucosa-submucosa clip closure method for gastric lesions.AIM To elucidate the efficacy of the endoscopic mucosa-submucosa clip closure method after gastric endoscopic submucosal dissection(ESD).METHODS Twenty-two patients who underwent gastric ESD and mucosa-submucosa clip closure were included in this study.In this method,endo-clips are placed at the edges of a mucosal defect.Additional endo-clips are then applied in the same way to facilitate reduction of the defect size.Additional endo-clips are applied to both sides of the mucosal defect.Complete closure can be achieved.We have also developed a“location score”and“closure difficulty index”for assessment purposes.RESULTS Complete closure was achieved in 68.2%of the patients(15/22).The location score in the failure group was significantly larger than that in the complete closure group(P=0.023).The closure difficulty index in the failure group was significantly higher than that in the complete closure group(P=0.007).When the cutoff value of the closure difficulty index was set at 99,the high closure difficulty index predicted failure with a sensitivity of 57.1%,specificity of 100%,and accuracy of 86.3%.CONCLUSION The endoscopic mucosa-submucosa clip closure method was unreliable after gastric ESD,especially in cases with a high closure difficulty index. 展开更多
关键词 Endoscopic submucosal dissection STOMACH Endoscopic mucosa-submucosa clip closure method Colorectal
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CHGS method for numerical forecasting of typhoon waves-Ⅰ. Spectrum of waves in growing phase
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作者 Sui Shifeng South China Sea Institute of Oceanology, Academia Sinica, Guangzhou, China 《Acta Oceanologica Sinica》 SCIE CAS CSCD 1990年第3期343-352,共10页
Owing to the fact that the wind speed and direction of typhoon vary rapidly with time and space in typhoon fetch; the nearer to the typhoon eye the greater the wind velocity, and the shorter the wind fetch the smaller... Owing to the fact that the wind speed and direction of typhoon vary rapidly with time and space in typhoon fetch; the nearer to the typhoon eye the greater the wind velocity, and the shorter the wind fetch the smaller the wind time,as a result,the more difficult for the wind wave to fully grow. Hence.in typhoon wave numerical calculation it is impossible to use the model for a fully grown wave spectrum. Lately, the author et at. presented a CHGS method for numerical forecasting of typhoon waves, where a model for the growing wave spectrum was set up (see Eq. (2) in the text). The model involves a parameter indicating the growing degree of wind wave, i. e. ,the mean wave age β. When βvalue is small, the wave energy is chiefly concentrated near the peak frequency, so that the spectral peak gets high and steep; with the increase of β the spectral shape gradually gets lower and gentler; when β=Ⅰ, the wave fully grows, the growing spectrum becomes a fully grown P-M spectrum. The model also shows a spectral “overshooting” phenomenon within the “balance zone”. 展开更多
关键词 Spectrum of waves in growing phase CHGS method for numerical forecasting of typhoon waves
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Study on Growing Enterprise Operation Profit Management Method
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作者 Wu Xiukui 《International Journal of Technology Management》 2014年第7期56-57,共2页
With the rapid development of economy and constant improvement of social market economy system, the trade between countries is becoming more frequent and the competition is more intensified. As the main body of econom... With the rapid development of economy and constant improvement of social market economy system, the trade between countries is becoming more frequent and the competition is more intensified. As the main body of economy market, enterprises' competition is also expanding and strengthening, and fierce competition makes the disadvantaged enterprise withdrawal and also promotes the new enterprise. But the growing enterprise wants to grow sturdily, which is affected by many factors. It needs to face many challenges and cope with various problems. Some problems may not be in place, and they can not find any guidance examples, and this needs enterprise to analyze and choose. Slightly careless, emerging enterprises will be nipped in the cradle. This paper analyzes the operation management mode for the growing enterprise, based on this, it finds out the operation concept and proper operation mode suitable for the long-term development of enterprise, inorder to provide help for relevant stat^t: 展开更多
关键词 growing enterprise operation profit management method RESEARCH
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Study on the Effect of Magnetic Pole Clipping Angle on the Eddy Current Loss of Permanent Magnets in the Rotor of Magnetically Levitated Permanent Magnet Synchronous High-Speed Electric Spindles
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作者 Xiangjun Shen Houcai Liu +2 位作者 Huimin Kang Ruirong He Jiale Xi 《Open Journal of Applied Sciences》 2024年第11期3261-3281,共21页
Aiming at the problem of high temperature and even demagnetization failure of permanent magnet (PM) due to PM eddy current loss in PM synchronous high-speed motors, this paper proposes a technique to lessen PM eddy cu... Aiming at the problem of high temperature and even demagnetization failure of permanent magnet (PM) due to PM eddy current loss in PM synchronous high-speed motors, this paper proposes a technique to lessen PM eddy current loss by cutting the angle of PM poles to change the shape of PM structure. Firstly, an analysis is conducted on the mechanism of PM synchronous high-speed motor eddy current loss production, the theoretical analytical model of PM eddy current loss is deduced, and it is theoretically proved that the magnetic pole shaving angle can reduce PM eddy current loss. Then, a 25 KW surface-type PM synchronous high-speed motor as an object, using two-dimensional time-step finite element method (FEM) to model and analyze PM eddy current loss. The results show that the smaller the PM pole shaving angle, the less its eddy current loss will be, it is possible to minimize the pole shaving angle of eddy current loss by 9.8% compared to the unshaved angle. Finally, the temperature field of the PM is calculated using a finite element method, and the outcomes demonstrate that the maximum temperature of the PM with a magnetic pole shaving angle can be reduced by about 5% compared with the unshaved angle. 展开更多
关键词 Magnetic Pole clipping Permanent Magnet (PM) Eddy Current Loss Temperature Field Two-Dimensional Time-Stepped Finite Element method (FEM)
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改良结扎法用于脊髓损伤造模的优势分析
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作者 李道辉 徐晓霜 +5 位作者 李郑涛 田新鹏 毕航川 刘源 戴永文 陈凌强 《中国组织工程研究》 CAS 北大核心 2025年第2期379-384,共6页
背景:目前根据脊髓损伤的损伤方式不同衍生出不同的模型构建方法,传统物理损伤造模方法都有各自的优缺点,尚缺乏较为有效和稳定的脊髓损伤动物模型。目的:建立一种可复制、可调控、创伤小、死亡率低、模型更稳定、适用范围广、术后护理... 背景:目前根据脊髓损伤的损伤方式不同衍生出不同的模型构建方法,传统物理损伤造模方法都有各自的优缺点,尚缺乏较为有效和稳定的脊髓损伤动物模型。目的:建立一种可复制、可调控、创伤小、死亡率低、模型更稳定、适用范围广、术后护理时间短的脊髓损伤大鼠模型。方法:将体质量和鼠龄相似的40只SD大鼠随机分为对照组和改良组,每组20只,对照组采用钳夹造模法构建脊髓损伤模型,改良组选用基于压迫法改良的结扎法,在开窗的基础上使用缝线结扎的方法进行脊髓损伤的造模。比较两组大鼠的排尿行为、血尿、脓尿(感染率)、死亡率、脊柱畸形率及术后1,3,5,7 d的BBB运动功能学评分。结果与结论:基于压迫法改良的结扎法建立的脊髓损伤大鼠模型比常规建模方法排尿行为恢复较快、血尿率低、感染率低、死亡率低、脊柱畸形率低,BBB评分结果更集中稳定(1周内均<2分),由此可证明基于压迫法改良的结扎法更适用于脊髓损伤大鼠模型的建立。 展开更多
关键词 改良 脊髓损伤模型 钳夹造模法 结扎法 排尿反射 排尿行为 脊柱畸形 BBB评分
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S-Clip箍筋约束混凝土轴心受压短柱三维有限元分析
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作者 何世钦 李贺 +1 位作者 李鹏飞 安雪晖 《北方工业大学学报》 2014年第3期73-77,共5页
基于提高钢筋混凝土短柱抗震性能的要求,采用复合箍筋使得配筋量加大,施工质量不易保证.一种新型配筋方式S-Clip箍筋,可大大简化施工工序,确保施工质量.目前已有大量试验验证该种配筋形式的有效性,鉴于试验的局限性,本文应用三维有限元... 基于提高钢筋混凝土短柱抗震性能的要求,采用复合箍筋使得配筋量加大,施工质量不易保证.一种新型配筋方式S-Clip箍筋,可大大简化施工工序,确保施工质量.目前已有大量试验验证该种配筋形式的有效性,鉴于试验的局限性,本文应用三维有限元分析软件COM3D对S-Clip箍筋约束混凝土柱的轴心受压性能进行了分析,分析了混凝土强度等级、纵筋配筋和箍筋配置方式对箍筋约束混凝土柱力学性能的影响,以进一步研究S-Clip箍筋的性能,为工程设计与应用提供参考. 展开更多
关键词 S-clip箍筋 轴心受压 三维有限元分析 约束混凝土柱
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Determining structural variation in a managed mixed stand in an old-growth forest, northern Iran
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作者 Mohsen Javanmiri Pour Mohammad Reza Marvi Mohadjer +1 位作者 Vahid Etemad Meghdad Jourgholami 《Journal of Forestry Research》 SCIE CAS CSCD 2019年第5期1859-1871,共13页
Numerous approaches have been developed to quantify forest structure modules.A variety has measured each as part of stand attributes.This study was carried out in managed mixed stands in northern Iran.The objective wa... Numerous approaches have been developed to quantify forest structure modules.A variety has measured each as part of stand attributes.This study was carried out in managed mixed stands in northern Iran.The objective was to quantify stand structure and its variation before and after tree marking through the Gini index and structural triangle method.A full sampling inventory was taken in 2004 and 2014 at the beginning and end of a period,before and after tree marking operations in five stands.The results indicate that the Gini index was 39.5,62.2,43.0,82.0 and 74.0%forⅠ,Ⅱ,Ⅲ,ⅣandⅤstands respectively.Furthermore,approximate structural diameters were determined as a large category forⅠ,Ⅱ,ⅢandⅤstands while standⅡhad an intermediate-large class pre-tree marking to an intermediate-small class post-tree marking.The paired t-test results were not significant for tree numbers and growing stock changes for all species,and for beech,hornbeam,and velvet maple before and after tree harvesting in the whole stand.Therefore,the Gini index and the structural triangle method can be used for natural stand modeling,structural diversity designation,and for management practices in nature-oriented forestry strategies. 展开更多
关键词 GINI index growING STOCK Mixed STAND Structure changes Structural TRIANGLE method
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基于MDPSO-Clipping联合算法降低峰均功率比 被引量:1
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作者 张翼 曹建蜀 刘雪阳 《计算机仿真》 北大核心 2019年第5期305-309,共5页
针对正交频分复用系统中峰均功率比较高的问题,对传统的部分传输序列法作出改进,以降低信号的峰均功率比。改进的原理是将部分传输序列法中相位因子的选取与改进后的离散粒子群优化算法(modified discrete particle swarm optimization,... 针对正交频分复用系统中峰均功率比较高的问题,对传统的部分传输序列法作出改进,以降低信号的峰均功率比。改进的原理是将部分传输序列法中相位因子的选取与改进后的离散粒子群优化算法(modified discrete particle swarm optimization,MDPSO)相结合,得到峰均功率比降低后的信号,再将该信号利用限幅法(Clipping)进行削峰处理以达到进一步降低峰均功率比的效果。实验数据表明,在损失微小的误码率情况下,MDPSO-Clipping算法的峰均功率比优于PTS算法的峰均功率比0.4dB左右,且上述算法的时间复杂度更低。 展开更多
关键词 正交频分复用 峰均功率比 部分传输序列法 离散粒子群算法 限幅法
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基于机器视觉的芯片字符区域分割和定位算法 被引量:1
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作者 陈甦欣 赵安宁 罗乐文 《组合机床与自动化加工技术》 北大核心 2024年第4期10-13,18,共5页
芯片表面的字符对分选具有重要意义,对字符的定位是分选工作的关键步骤。为了提高分选工作定位效率和定位精度,提出了一种基于改进的区域生长算法和凸包检测算法分割和定位芯片表面字符区域方法。首先,对采集图像进行预处理操作,利用改... 芯片表面的字符对分选具有重要意义,对字符的定位是分选工作的关键步骤。为了提高分选工作定位效率和定位精度,提出了一种基于改进的区域生长算法和凸包检测算法分割和定位芯片表面字符区域方法。首先,对采集图像进行预处理操作,利用改进的Canny算法获取无干扰图像边缘,将图像边缘作为区域生长法的种子点并以图像自适应阈值作为生长准则分割图像,使用最大内接矩形算法粗定位字符区域;其次,采用Harris角点检测算法获取字符角点分布位置;最后,筛选角点并提取关键点,利用一种改进的凸包检测算法定位字符区域。经过实验验证,所设计的算法能够完整的分割和定位芯片表面字符区域,定位精度和效率较原有方法提升5.3%和15.4%,满足实际工业生产的要求。 展开更多
关键词 机器视觉 区域生长法 角点检测 凸包检测 字符定位
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西藏地区一种新的四季划分方法 被引量:1
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作者 史继清 周刊社 +3 位作者 张东东 杜军 甘臣龙 普布多吉 《干旱区地理》 CSCD 北大核心 2024年第5期773-784,共12页
利用西藏地区38个气象站点1981—2022年逐日气温资料,分析常用气候季节划分方法在西藏地区的适用性,指出各种季节划分方法的不足和局限,基于西藏物候和主要农作物生育期提出的季节划分气温阈值等指标,筛选出适于西藏地区的季节划分方法... 利用西藏地区38个气象站点1981—2022年逐日气温资料,分析常用气候季节划分方法在西藏地区的适用性,指出各种季节划分方法的不足和局限,基于西藏物候和主要农作物生育期提出的季节划分气温阈值等指标,筛选出适于西藏地区的季节划分方法及气温阈值,分析了西藏地区的四季开始日和长短的变化特征。结果表明:(1)常用气候季节划分方法在西藏地区应用有一定的局限性,而西藏物候季节划分方法和生育期季节划分方法适用于西藏高原地区的农事活动。(2)基于阈值“6℃、15℃”“5℃、16℃”“6℃、16℃”和“6℃、17℃”分析典型气象站四季时间长度变化特征发现,改则冬季时间长度长于其他季节、察隅夏季时间长度长于其他季节,且拉萨、昌都、改则、察隅四季长度均呈现夏季上升和秋冬季下降的趋势。(3)拉萨和昌都的夏季平均气温进行突变检验发现两站分别于2011年和2017年出现突变,佐证了夏季阈值取17℃的合理性。(4)西藏新四季划分法指标为“6℃、17℃”,该指标划分西藏四季发现,夏季站点主要分布在雅鲁藏布江一线的较低海拔地区;春、秋季持续时间整体呈现西北部和南部偏短、中东部偏长的特征,夏季呈现中部偏长、四周偏短的特点,冬季与春秋季则相反;四季时空特征符合西藏地区实际情况。春、夏、秋、冬季平均开始日分别为3月21日、6月16日、7月25日、11月3日。 展开更多
关键词 季节划分方法 气温阈值 物候 生育期 西藏
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仿生消化法估测生长猪饲料有效能的准确性及可加性研究
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作者 任聪 张虎 +3 位作者 王钰明 解竞静 萨仁娜 赵峰 《畜牧兽医学报》 CAS CSCD 北大核心 2024年第9期3988-4000,共13页
旨在探讨仿生消化法估测生长猪饲料原料消化能(DE)、代谢能(ME)和净能(NE)的准确性和可加性,为快速获得生长猪饲料的有效能值提供参考。采用单因素完全随机设计,以生长猪仿生消化法测定12个能量饲料、9个蛋白质饲料,以及由上述21个饲料... 旨在探讨仿生消化法估测生长猪饲料原料消化能(DE)、代谢能(ME)和净能(NE)的准确性和可加性,为快速获得生长猪饲料的有效能值提供参考。采用单因素完全随机设计,以生长猪仿生消化法测定12个能量饲料、9个蛋白质饲料,以及由上述21个饲料原料配制的17个饲粮的酶水解物能值(EHGE),每个处理5个重复,每个重复1根消化管。通过EHGE、粗蛋白(CP)和酸性洗涤纤维(ADF)估测DE、ME及NE值。比较饲料原料有效能(DE、ME、NE)估测值与GB/T 39235-2020中同本研究同名的17个饲料原料的能量利用率乘以总能(GE)实测值得出的体内有效能值的差异及相关性,以验证仿生消化法估测饲料有效能的准确性。根据饲料原料的有效能估测值计算饲粮有效能加权值,并根据饲粮EHGE估测有效能的数学模型获得饲粮的有效能值,比较两者的差异以验证仿生消化法估测饲料有效能值的可加性。结果表明,采用GB/T 39235-2020计算的17个饲料原料的DE、ME、NE对EHGE结合CP、ADF估测的有效能值线性回归模型的决定系数(R2)分别为0.774,0.778和0.870。回归诊断分析发现,米糠、小麦麸和玉米胚芽粕偏离了其他14个饲料原料样品体内值与估测值的线性关系■。剔除上述3个样品后,GB/T 39235-2020计算的体内有效能对估测值线性回归的决定系数高于0.93。17个试验饲粮的EHGE实测值对加权计算值,DE、ME和NE的估测值对加权计算值的线性回归与Y=X重叠(R2>0.95,P<0.01)。上述结果表明,仿生消化法可以满意地估测14个饲料样品的有效能值,但低估了米糠和小麦麸的有效能值,却高估了玉米胚芽粕的DE和ME。仿生消化法测定的EHGE及通过EHGE估测的DE、ME、NE均具有良好的可加性。 展开更多
关键词 生长猪 饲料原料 仿生消化法 有效能
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一种基于机载激光雷达点云的建筑物识别方法
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作者 方淑燕 赵健乐 +1 位作者 王辛 赵健 《现代电子技术》 北大核心 2024年第21期97-100,共4页
以三维激光雷达数据为基础进行目标自动检测识别具有重要现实意义。针对传统的以人工判读识别目标的方法已经远不能满足从海量数据中确定目标的要求,文中提出一种基于机载激光雷达点云的建筑物识别方法。通过使用改进后的金字塔方法构... 以三维激光雷达数据为基础进行目标自动检测识别具有重要现实意义。针对传统的以人工判读识别目标的方法已经远不能满足从海量数据中确定目标的要求,文中提出一种基于机载激光雷达点云的建筑物识别方法。通过使用改进后的金字塔方法构建三维激光雷达点云,鉴于三维激光点云具有地物本身的语义信息,可根据点云的多尺度复杂地物特征实现三维激光点云数据的自动分类,对分类后的非地面点进行区域生长分割,通过点云与建筑物平面特征的匹配,确定建筑物的识别结果。整个方案实现过程清晰、简单,而且该方法的实现对计算机硬件配置要求不高,能够从海量三维激光雷达数据中快速、准确地识别类建筑物,正确率高达81.25%,在目标识别领域具有较高的应用价值。 展开更多
关键词 激光雷达 点云 金字塔方法 点云分割 智能识别 区域生长分割
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不同冬灌方式对紫花苜蓿次年生长及土壤水热的影响
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作者 刘晋 郑和祥 +2 位作者 邬佳宾 王国帅 何锐 《节水灌溉》 北大核心 2024年第2期55-61,共7页
为探寻干旱半干旱地区冬季灌水对土壤水分、温度以及翌年紫花苜蓿返青、生长和产量的影响,进而提出适宜于伊金霍洛旗地区紫花苜蓿高产的灌溉方式,采用大田试验的方法,以未冬灌小区作为对照(CK),设置地下滴灌(DI)和畦灌(BI)2种灌溉方式,... 为探寻干旱半干旱地区冬季灌水对土壤水分、温度以及翌年紫花苜蓿返青、生长和产量的影响,进而提出适宜于伊金霍洛旗地区紫花苜蓿高产的灌溉方式,采用大田试验的方法,以未冬灌小区作为对照(CK),设置地下滴灌(DI)和畦灌(BI)2种灌溉方式,灌水定额设置为30 mm,共3个试验处理,每个处理3次重复,共9个试验小区。结果表明冬灌对次年紫花苜蓿返青时各土层土壤含水率和土层温度均有一定影响,地下滴灌和畦灌,均能提高紫花苜蓿返青前的土壤含水率、提高土壤温度、改善紫花苜蓿的越冬环境、提高紫花苜蓿的越冬率。冬灌后次年紫花苜蓿返青率较未冬灌处理小区高13.77%,且滴灌处理条件下返青率最高,有利于后期紫花苜蓿产量的提高。地下滴灌冬灌处理条件下紫花苜蓿第1茬产量最高,鲜草产量为31020 kg/hm^(2),干草产量为6150 kg/hm^(2),相对未冬灌处理分别增产23.32%、21.67%。综合考虑地下滴灌条件下冬灌对次年紫花苜蓿生长及土壤水热的影响,建议伊金霍洛旗地区紫花苜蓿在越冬期进行地下滴灌条件下的冬灌。 展开更多
关键词 紫花苜蓿 冬灌 灌溉方式 地下滴灌 土壤水热 土壤水分 土壤温度 生长 产量
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紫花苜蓿微型蔬菜栽培基质及品种筛选研究
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作者 杨静 高艳文 +1 位作者 张英俊 谢越 《北方园艺》 CAS 北大核心 2024年第3期9-16,共8页
以紫花苜蓿品种‘WL525HQ’为试材,采用单因素完全随机设计,设定6种不同栽培基质配比及2种不同种植方式,通过测定其发芽率、地上地下生物量和根系形态,筛选适宜紫花苜蓿微型蔬菜栽培的基质及种植方式;以28个紫花苜蓿品种为试材,采用单... 以紫花苜蓿品种‘WL525HQ’为试材,采用单因素完全随机设计,设定6种不同栽培基质配比及2种不同种植方式,通过测定其发芽率、地上地下生物量和根系形态,筛选适宜紫花苜蓿微型蔬菜栽培的基质及种植方式;以28个紫花苜蓿品种为试材,采用单因素完全随机设计,通过测定皂苷含量、刀豆氨酸含量,筛选出作为微型蔬菜生产的最佳紫花苜蓿品种;通过灰色关联度分析刀豆氨酸含量与公司、产地和秋眠级的关联度,以期为筛选紫花苜蓿微型蔬菜生产的基质、种植方式和品种提供参考依据。结果表明:紫花苜蓿微型蔬菜在草炭∶蛭石=1∶1(S1处理)的混合基质栽培下,地上、地下部生物量最高;相较于催芽移栽,直接播种的紫花苜蓿长势更好;28个紫花苜蓿品种中,‘WL363HQ’的刀豆氨酸含量最低,可作为紫花苜蓿微型蔬菜生产的最佳品种。紫花苜蓿品种产地、秋眠级与刀豆氨酸含量关联度较大,可为紫花苜蓿微型蔬菜品种筛选提供参考依据。 展开更多
关键词 微型蔬菜 紫花苜蓿 基质 种植方式 品种
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两条B样条曲线求交的高效计算方法
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作者 王永澳 吕杭汀 陈小雕 《计算机辅助设计与图形学学报》 EI CSCD 北大核心 2024年第5期687-700,共14页
曲线曲面间求交计算在CG和CAD中有着广泛的应用.牛顿法等迭代法计算效率高但需要良好的初始值;裁剪法具有良好的鲁棒性但计算效率不理想,尤其是对于相切情况的求交问题.为此,提出一种计算2条B样条曲线交点的混合方法.首先提出一种高效... 曲线曲面间求交计算在CG和CAD中有着广泛的应用.牛顿法等迭代法计算效率高但需要良好的初始值;裁剪法具有良好的鲁棒性但计算效率不理想,尤其是对于相切情况的求交问题.为此,提出一种计算2条B样条曲线交点的混合方法.首先提出一种高效的线性复杂度裁剪方法,用于获得良好的初始值;然后提出一种与导数无关且效率更高的改进的割线法,用于验证贯穿性相交情况;最后提出一个相切情况下收敛阶为2的迭代公式,其性能远优于现有的牛顿法和裁剪法.理论上,混合方法若与根隔离法相结合,可以应用于更多类型曲线间的求交问题.数值实验结果表明,与现有的同类方法相比,在贯穿情况下,所提方法的计算效率提高约10%,在相切情况下则提高约100%~300%. 展开更多
关键词 B样条曲线/曲线求交 裁剪法 线性包围法 相切 非多项式函数
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基于区域生长法的无人机和无人船一体化测绘技术研究
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作者 侍恒 曾贺 +2 位作者 苏磊 张宝森 刘昌辉 《人民黄河》 CAS 北大核心 2024年第11期137-141,148,共6页
针对控导工程监测过程中采用的传统水下高程测量方法存在操作人员多、安全隐患大等问题,以神堤控导工程12坝—20坝为例,采用无人机、无人船等非载人式勘测技术,对河道水上地形和水下地形展开同步测量。引入坡度因子对区域生长法进行改进... 针对控导工程监测过程中采用的传统水下高程测量方法存在操作人员多、安全隐患大等问题,以神堤控导工程12坝—20坝为例,采用无人机、无人船等非载人式勘测技术,对河道水上地形和水下地形展开同步测量。引入坡度因子对区域生长法进行改进,以目视解译方法识别的林木区域为基准,分析对比区域生长法和考虑坡度的区域生长法的识别准确率。采用自然邻域法对水下地形数据进行插值并与水上地形数据融合,得到神堤控导工程水上水下数字高程模型(DEM),并与工程三维视图进行对比。结果表明:利用无人机和无人船一体化测绘生成的DEM成果,满足有关技术规范的要求,具有较高的精度;采用考虑坡度的区域生长法识别控导工程的防浪林和行道林,识别正确率达92.47%。 展开更多
关键词 无人机 无人船 水下地形 水上地形 区域生长法 神堤控导工程
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