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传统SMB、Varicol和Partial-discard工艺分离纯化ECG和EGCG的比较研究 被引量:2
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作者 黄永东 江和源 +5 位作者 江用文 张建勇 王斌 白艳 文志浩 王伟伟 《茶叶科学》 CAS CSCD 北大核心 2011年第3期201-210,共10页
使用B型三带模拟移动床技术,以C18键合硅胶为固定相,乙醇与水(20︰80,V/V)为流动相,分别采取传统SMB工艺、Varicol工艺和Partial-discard工艺分离98%的茶多酚(TP98)。以得到高纯度和高回收率的ECG和EGCG为目标,分别优化柱配置、切换时... 使用B型三带模拟移动床技术,以C18键合硅胶为固定相,乙醇与水(20︰80,V/V)为流动相,分别采取传统SMB工艺、Varicol工艺和Partial-discard工艺分离98%的茶多酚(TP98)。以得到高纯度和高回收率的ECG和EGCG为目标,分别优化柱配置、切换时间、进样流速、冲洗流速。结果表明,采用Varicol工艺能得到纯度为91.33%的ECG,回收率为91.41%;采用Partial-discard工艺能得到纯度为90.12%的EGCG,回收率为97.83%。相对于传统模拟移动床,Varicol工艺具有提高产品纯度和回收率的优点,Partial-discard工艺具有提高收集液浓度和产品纯度的优点。 展开更多
关键词 模拟移动床 EGCG ECG Varicol工艺 partial-discard工艺
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坐标转换Partial-EIV总体最小二乘方法 被引量:4
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作者 王乐洋 郑玄威 +2 位作者 申兴林 许光煜 于冬冬 《测绘工程》 CSCD 2015年第12期12-16,共5页
在测量数据处理过程中,针对系数矩阵中同时存在随机元素和固定元素的情况,Xu等通过将随机元素分离使EIV模型推广到Partial-EIV模型,并给出基于Partial-EIV模型的总体最小二乘(TLS)算法。文中介绍该算法,并将其应用在平面及空间的坐标转... 在测量数据处理过程中,针对系数矩阵中同时存在随机元素和固定元素的情况,Xu等通过将随机元素分离使EIV模型推广到Partial-EIV模型,并给出基于Partial-EIV模型的总体最小二乘(TLS)算法。文中介绍该算法,并将其应用在平面及空间的坐标转换中,通过与最小二乘(LS)、总体最小二乘(TLS)及加权总体最小二乘(WTLS)方法的比较和分析,验证该算法有效性。 展开更多
关键词 总体最小二乘 partial-EIV模型 函数模型 系数矩阵 坐标转换
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基于Partial-EIV模型的TLS姿态估计方法 被引量:2
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作者 田源 隋立芬 +3 位作者 高成胜 王冰 文娜 田翌君 《测绘科学技术学报》 CSCD 北大核心 2017年第6期587-592,共6页
推导了基于乘性姿态角误差的观测方程,顾及其系数矩阵也含有误差的特点提出一种利用整体最小二乘原理估计姿态参数的新思路。该问题的系数矩阵中同时存在随机元素和固定元素且存在结构性特征,故引入Partial-EIV模型,设计了一种符合其系... 推导了基于乘性姿态角误差的观测方程,顾及其系数矩阵也含有误差的特点提出一种利用整体最小二乘原理估计姿态参数的新思路。该问题的系数矩阵中同时存在随机元素和固定元素且存在结构性特征,故引入Partial-EIV模型,设计了一种符合其系数矩阵结构特点的新模型。最后通过两组仿真实验将其与已有姿态估计方法进行对比,得出结论:基于Partial-EIV模型的整体最小二乘解法解算精度高于常规最小二乘法;其解算效果与基于乘性姿态角误差的最小二乘法基本一致。表明本文提出的方法正确有效。 展开更多
关键词 多天线测姿 姿态参数估计 乘性姿态误差 整体最小二乘 partial-EIV模型
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Separation of Salbutamol by Nano-baskets of Calix[4]arene Bearing Sulfonyl-carboxamides in Partial-cone Conformation 被引量:3
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作者 MOKHTARI Bahram POURABDOLLAH Kobra 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2012年第6期1112-1118,共7页
Salbutamol,which increases the muscle mass and decreases the adipose tissue,is misused as nutrient repartitioning agent in the livestock.The novelty of this work is the determination of salbutamol in the livestock mea... Salbutamol,which increases the muscle mass and decreases the adipose tissue,is misused as nutrient repartitioning agent in the livestock.The novelty of this work is the determination of salbutamol in the livestock meat via new bonded-phases bearing eight derivatives of p-tert-calix[4]arene in partial-cone conformation.The new synthesized bonded-phases were characterized and optimized.The bonding interactions of solute and stationary-phases were examined and the main interactions were reported.The salbutamol levels in six samples of livestock meat were analyzed and the results reveal that for the best bonded-phases,the limit of detection(LOD) and limit of quantitation(LOQ) were 0.02 and 0.06 μg/mL,respectively. 展开更多
关键词 NANO-BASKET Bonded-phase partial-cone conformation CALIX[4]ARENE SALBUTAMOL
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A new structure and its analytical model for the vertical interface electric field of a partial-SOI high voltage device 被引量:2
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作者 胡盛东 张波 +1 位作者 李肇基 罗小蓉 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第3期496-502,共7页
A new partial-SOI (PSOI) high voltage device structure called a CI PSOI (charge island PSOI) is proposed for the first time in this paper. The device is characterized by a charge island layer on the interface of t... A new partial-SOI (PSOI) high voltage device structure called a CI PSOI (charge island PSOI) is proposed for the first time in this paper. The device is characterized by a charge island layer on the interface of the top silicon layer and the dielectric buried layer in which a series of equidistant high concentration n+-regions is inserted. Inversion holes resulting from the vertical electric field are located in the spacing between two neighbouring n+-regions on the interface by the force with ionized donors in the undepleted n+-regions, and therefore effectively enhance the electric field of the dielectric buried layer (Ei) and increase the breakdown voltage (BV), thereby alleviating the self-heating effect (SHE) by the silicon window under the source. An analytical model of the vertical interface electric field for the CI PSOI is presented and the analytical results are in good agreement with the 2D simulation results. The BV and El of the CI PSOI LDMOS increase to 631 V and 584 V/μm from 246 V and 85.8 V/μm for the conventional PSOI with a lower SHE, respectively. The effects of the structure parameters on the device characteristics are analysed for the proposed device in detail. 展开更多
关键词 interface charges breakdown voltage partial-SOI self-heating effect
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Study of LDPC Coded SFH System with Partial-Band Interference 被引量:3
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作者 Chao Gong Manxi Wang +1 位作者 Daoxing Guo Xiaofei Pan 《Communications and Network》 2013年第3期280-285,共6页
The application of Low Density Parity Check (LDPC) code in the anti-interference systems has drawn an increasing attention, due to its admiring performance which is very close to the theory limit. This paper focuses o... The application of Low Density Parity Check (LDPC) code in the anti-interference systems has drawn an increasing attention, due to its admiring performance which is very close to the theory limit. This paper focuses on a LDPC encoded slow frequency hopping (SFH) communication system with partial-band interference. Firstly, a modified soft- decision algorithm based on the utilization of interference information is proposed, and its performance is compared with some other soft-decision methods. Secondly, with numerical simulation, the influence of code rate, code length and the number of symbols per hops on the performance of the system with partial band noise interference is illustrated and examined in detail. Considering the great influence of hops per symbol on the performance, interleaver should be used and its influence on the performance is further examined by simulation. Finally, some constructive advises for the design of LDPC coded SFH system are given. Simulation results show that, with a reasonable design, the SFH system with LDPC code could achieve a desirable performance. 展开更多
关键词 LDPC SFH Soft-decision partial-band INTERFERENCE
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Partial-EIV数据探测法在三维坐标转换中的应用 被引量:1
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作者 王铮尧 倪标 《地理空间信息》 2019年第9期116-118,I0003,共4页
在三维坐标转换中,起始和目标坐标系下的点坐标均可能存在粗差,利用总体最小二乘法求解坐标转换参数时会对计算结果产生较大影响。为了降低粗差对计算结果的影响,利用基于Partial-EIV模型的数据探测法对原始数据进行粗差剔除,以保证结... 在三维坐标转换中,起始和目标坐标系下的点坐标均可能存在粗差,利用总体最小二乘法求解坐标转换参数时会对计算结果产生较大影响。为了降低粗差对计算结果的影响,利用基于Partial-EIV模型的数据探测法对原始数据进行粗差剔除,以保证结果的正确性。 展开更多
关键词 三维坐标 粗差 总体最小二乘 partial-EIV 数据探测法
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附加一次和二次等式约束的Partial-EIV模型及相应算法 被引量:1
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作者 韩杰 张松林 《测绘科学技术学报》 北大核心 2019年第1期17-22,27,共7页
研究了附加一次和二次等式约束的Partial-EIV模型,推导了加权整体最小二乘估计准则下相应的计算公式,并讨论了仅附加一次等式约束的Partial-EIV模型和仅附加二次等式约束的Partial-EIV模型。通过正交线性回归和平面坐标转换两个算例进... 研究了附加一次和二次等式约束的Partial-EIV模型,推导了加权整体最小二乘估计准则下相应的计算公式,并讨论了仅附加一次等式约束的Partial-EIV模型和仅附加二次等式约束的Partial-EIV模型。通过正交线性回归和平面坐标转换两个算例进行实验,将新算法与已有的附加等式约束的EIV模型的方法进行了对比,发现文中方法计算效率更高,且适用于结构化EIV模型的求解。 展开更多
关键词 整体最小二乘 partial-EIV模型 等式约束 正交线性回归 平面坐标转换
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Acute effects of partial-body vibration in sitting position
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作者 Yannik Faes Nora Banz +4 位作者 Nathalie Buscher Angela Blasimann Lorenz Radlinger Patric Eichelberger Achim Elfering 《World Journal of Orthopedics》 2018年第9期156-164,共9页
AIM To investigate the acute effects of sinusoidal and stochastic resonance partial-body vibration in sitting position, including muscle activity, heart rate variability, balance and flexibility.METHODS Fifty healthy ... AIM To investigate the acute effects of sinusoidal and stochastic resonance partial-body vibration in sitting position, including muscle activity, heart rate variability, balance and flexibility.METHODS Fifty healthy participants were assigned randomly to two training conditions: A sinusoidal partial-body vibration(SIN, 8 Hz) or a stochastic resonance partial-body vibration(STOCH, 8 ± 2 Hz). For baseline assessment participants sat on the vibration platform without vibration. Both training conditions consisted of five series of a one-minute vibration training and a one-minutebreak between them. In this experimental study surface electromyography(EMG) of the erector spinae(ES), one of the back muscles, and heart rate variability(HRV) was measured at baseline and during training. Balance and flexibility were assessed at baseline and immediately after training. Balance was measured with the modified star excursion balance test(mS EBT) and flexibility was assessed through the modified fingertip-to-floor method(mF TF).RESULTS Paired sample t-test showed a significant increase in balance that was restricted to STOCH(t =-2.22, P = 0.018; SIN: t =-0.09, P = 0.466). An increase in flexibility was also restricted to STOCH(t = 2.65, P = 0.007; SIN: t = 1.41, P = 0.086). There was no significant change of muscle activity in the ES-EMG in STOCH or SIN conditions. In both training conditions, HRV decreased significantly, but remained in a low-load range(STOCH: t = 2.89, P = 0.004; SIN: t = 2.55, P = 0.009).CONCLUSION In sitting position, stochastic resonance partial-body vibration can improve balance and flexibility while cardiovascular load is low. STOCH can be a valuable training option to people who are unable to stand(e.g., people, who are temporarily wheelchair-bound). 展开更多
关键词 partial-body VIBRATION Balance FLEXIBILITY Sinusoidal Stochastic resonance
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Partial-SOI high voltage P-channel LDMOS with interface accumulation holes
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作者 吴丽娟 胡盛东 +2 位作者 罗小蓉 张波 李肇基 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第10期373-378,共6页
A new partial SOI (silion-on-insulator) (PSOI) high voltage P-channel LDMOS (lateral double-diffused metal-oxide semiconductor) with an interface hole islands (HI) layer is proposed and its breakdown character... A new partial SOI (silion-on-insulator) (PSOI) high voltage P-channel LDMOS (lateral double-diffused metal-oxide semiconductor) with an interface hole islands (HI) layer is proposed and its breakdown characteristics are investigated theoretically. A high concentration of charges accumulate on the interface, whose density changes with the negative drain voltage, which increase the electric field (Er) in the dielectric buried oxide layer (BOX) and modulate the electric field in drift region . This results in the enhancement of the breakdown voltage (BV). The values of E1 and BV of an HI PSOI with a 2-~m thick SOI layer over a 1-~tm thick buried layer are 580V/~m and -582 V, respectively, compared with 81.5 V/p.m and -123 V of a conventional PSOI. Furthermore, the Si window also alleviates the self-heating effect (SHE). Moreover, in comparison with the conventional device, the proposed device exhibits low on-resistance. 展开更多
关键词 interface charges breakdown voltage partial-SOI accumulation holes self-heating effect
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FORWARD LINK PARTIAL-BALANCE POWER CONTROL ALGORITHM FOR W-CDMA COMMUNICATION
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作者 Qiu Ling Zhang Lei Zhu Jinkang (PCN&SS Lab. University of Science and Technology of China, Hefei 230027) 《Journal of Electronics(China)》 2000年第1期25-30,共6页
Balance power control is based on the idea of balancing Carrier to Interference Ratio (CIR) of all wireless links. Unbalance power control means that different traffics can achieve different CIR at receivers. This pap... Balance power control is based on the idea of balancing Carrier to Interference Ratio (CIR) of all wireless links. Unbalance power control means that different traffics can achieve different CIR at receivers. This paper proposes a forward link partial-balance power control algorithm, which can provide necessary Quality of Service (QoS) for multimedia traffics in Wideband CDMA(W-CDMA) systems. The proposed algorithm is the integration of grading traffics priority and allocating and adjusting forward link power levels. For higher priority traffics, the unbalance power control is used. Whereas for lower priority traffics, balance power control is adopted. Computer simulation results show that the proposed algorithm can guarantee the special QoS requirements of the traffics with higher priority orders and maximize the CIR of the traffics with lower priority orders. 展开更多
关键词 W-CDMA system FORWARD LINK partial-balance power control
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基于Partial-EIV的数据探测法研究
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作者 王铮尧 梁菲 《中国煤炭地质》 2022年第11期74-78,共5页
为了解决EIV(Errors-In-Variables)模型的粗差问题,在Partial-EIV模型的基础上拓展数据探测法,对Partial-EIV的模型在(a_(0),β_(0))处进行线性展开,变换为最小二乘形式,进一步推导EIV模型下的单位权方差估计值,推导出数据探测法,通过... 为了解决EIV(Errors-In-Variables)模型的粗差问题,在Partial-EIV模型的基础上拓展数据探测法,对Partial-EIV的模型在(a_(0),β_(0))处进行线性展开,变换为最小二乘形式,进一步推导EIV模型下的单位权方差估计值,推导出数据探测法,通过算例分析,在观测值独立等精度情形下,可以有效地发现观测数据中的粗差。 展开更多
关键词 EIV模型 粗差探测 partial-EIV 单位权方差
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Feasibility of the partial-single arc technique in RapidArc planning for prostate cancer treatment 被引量:1
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作者 Suresh Rana ChihYao Cheng 《Chinese Journal of Cancer》 SCIE CAS CSCD 2013年第10期546-552,共7页
The volumetric modulated arc therapy(VMAT)technique,in the form of RapidArc,is widely used to treat prostate cancer.The full-single arc(f-SA)technique in RapidArc planning for prostate cancer treatment provides effici... The volumetric modulated arc therapy(VMAT)technique,in the form of RapidArc,is widely used to treat prostate cancer.The full-single arc(f-SA)technique in RapidArc planning for prostate cancer treatment provides efficient treatment,but it also delivers a higher radiation dose to the rectum.This study aimed to compare the dosimetric results from the new partial-single arc(p-SA)technique with those from the f-SA technique in RapidArc planning for prostate cancer treatment.In this study,10 patients with lowrisk prostate cancer were selected.For each patient,two sets of RapidArc plans(f-SA and p-SA)were created in the Eclipse treatment planning system.The f-SA plan was created using one full arc,and the p-SA plan was created using planning parameters identical to those of the f-SA plan but with anterior and posterior avoidance sectors.Various dosimetric parameters of the f-SA and p-SA plans were evaluated and compared for the same target coverage and identical plan optimization parameters.The f-SA and p-SA plans showed an average difference of±1%for the doses to the planning target volume(PTV),and there were no clear differences in dose homogeneity or plan conformity.In comparison to the f-SA technique,the p-SA technique reduced the doses to the rectum by approximately 6.1%to 21.2%,to the bladder by approximately 10.3%to 29.5%,and to the penile bulb by approximately 2.2%.In contrast,the dose to the femoral heads,the integral dose,and the number of monitor units were higher in the p-SA plans by approximately 34.4%,7.7%,and 9.2%,respectively.In conclusion,it is feasible to use the p-SA technique for RapidArc planning for prostate cancer treatment.For the same PTV coverage and identical plan optimization parameters,the p-SA technique is better in sparing the rectum and bladder without compromising plan conformity or target homogeneity when compared to the f-SA technique. 展开更多
关键词 治疗计划系统 SA技术 前列腺癌 ECLIPSE 辐射剂量 参数规划 优化参数 剂量分布
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Performance of Luby transform coded frequency hopping systems in partial-band jamming
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作者 卜祥元 邱源 +2 位作者 杨行 周荣花 马园园 《Journal of Beijing Institute of Technology》 EI CAS 2013年第3期367-373,共7页
Luby transform (LT) codes are proposed to suppress the effect of partial band noise jam- ming in frequency hopping (FH) communication systems. A decoding scheme for joint erasures of severely jammed symbols and er... Luby transform (LT) codes are proposed to suppress the effect of partial band noise jam- ming in frequency hopping (FH) communication systems. A decoding scheme for joint erasures of severely jammed symbols and error correction is proposed. If an uncorrectable error is detected, the receiver erases the jammed symbols and uses incremental redundancy to increase the error-correcting capability. The performance of LT codes, under power-oppressive partial band noise jamming ( PB- N J) with the additive white Gaussian noise (AWGN), is evaluated via simulation. Even if the jam- mer spreads its high power over half of the hopping bandwidth, LT codes are shown to achieve a tar- get bit error probability of 10 -5, demonstrating their effectiveness as high-performance codes to im- prove the ability of FH systems to combat varying partial band noise jamming. 展开更多
关键词 Luby transform (LT) codes frequency hopping (FH) erasure-correcting partial bandnoise jamming (PBNJ) anti-jam
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局部半包裹部分包覆钢-混凝土组合梁受弯性能试验研究 被引量:1
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作者 李亚明 刘宏欣 +3 位作者 贾水钟 杨宇焜 李杰 徐瑜 《建筑结构》 北大核心 2024年第4期1-8,共8页
针对部分包覆钢-混凝土组合梁柱节点区域后浇筑混凝土不易密实的问题,研究了受拉侧混凝土对局部半包裹部分包覆钢-混凝土组合梁(局部半包裹PEC梁)受弯性能的影响,进行了2根不同构造的局部半包裹PEC梁的四点弯曲试验,模拟局部半包裹PEC... 针对部分包覆钢-混凝土组合梁柱节点区域后浇筑混凝土不易密实的问题,研究了受拉侧混凝土对局部半包裹部分包覆钢-混凝土组合梁(局部半包裹PEC梁)受弯性能的影响,进行了2根不同构造的局部半包裹PEC梁的四点弯曲试验,模拟局部半包裹PEC梁负弯矩区受力状态,对其受弯性能、延性、破坏形式等展开分析。结果表明:局部半包裹PEC梁表现出良好的延性,挠度达到l_(0)/50时截面抗弯承载力并未下降。型钢主钢件、混凝土的应变沿截面高度方向大致呈线性变化,可引用平截面假定计算受弯承载力及刚度。局部半包裹PEC梁受拉侧混凝土对其极限承载力与破坏模式影响不大,在计算局部半包裹PEC梁柱节点受力时可不考虑受拉侧混凝土作用,节点后浇筑区域可采用半包裹填充,以加快施工进度。此外,对局部半包裹PEC梁进行建模,进行梁受弯过程的有限元分析,对比模拟结果与试验结果,二者荷载-挠度曲线吻合较好,误差均在10%以内。 展开更多
关键词 局部半包裹部分包覆钢-混凝土组合梁 破坏模式 受弯承载力 延性
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部分嵌套式设计在中医药“同病异治”疗效评价中的应用及方法学探索 被引量:1
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作者 冯硕 马继征 +3 位作者 郭玉峰 曹戬 胡晶 廖星 《中国中医药信息杂志》 CAS CSCD 2024年第4期26-30,共5页
目的本研究针对中医学同病异治、辨证论治的特征,引入部分嵌套式设计。方法部分嵌套式设计以复杂干预对照标准化治疗,中医组按“证型-治法-方药”分割为多个子集(存在嵌套结构),对照组采用标准化西医治疗(无嵌套结构);并以一项溃疡性结... 目的本研究针对中医学同病异治、辨证论治的特征,引入部分嵌套式设计。方法部分嵌套式设计以复杂干预对照标准化治疗,中医组按“证型-治法-方药”分割为多个子集(存在嵌套结构),对照组采用标准化西医治疗(无嵌套结构);并以一项溃疡性结肠炎“同病异治”数据为例,套用该设计类型并采用多水平模型分析。结果部分嵌套式设计符合“同病异治”诊疗特征并满足循证评价的设计要求,通过多水平模型可实现类似数据结构的分析。结论利用部分嵌套式设计能实现对“同病异治”整体效果的评价,可为中医药临床疗效评价提供方法学参考。 展开更多
关键词 部分嵌套式设计 同病异治 循证医学 疗效评价 方法学
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喜马拉雅造山带聂拉木地区渐新世深熔作用的厘定 被引量:1
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作者 高利娥 曾令森 +5 位作者 赵令浩 严立龙 李广旭 王亚莹 王海涛 王睿 《岩石学报》 SCIE EI CAS CSCD 北大核心 2024年第5期1565-1586,共22页
喜马拉雅新生代淡色花岗岩记录了地壳深熔作用和花岗岩侵位的地球化学和构造物理效应。与形成于增厚地壳条件下和伸展背景下的始新世和中新世花岗岩相比,渐新世花岗岩分布比较局限,且源区和形成机制还存在着较大的争议。位于喜马拉雅造... 喜马拉雅新生代淡色花岗岩记录了地壳深熔作用和花岗岩侵位的地球化学和构造物理效应。与形成于增厚地壳条件下和伸展背景下的始新世和中新世花岗岩相比,渐新世花岗岩分布比较局限,且源区和形成机制还存在着较大的争议。位于喜马拉雅造山带中部的聂拉木地区,可见32.1Ma的含电气石黑云母的花岗岩、29.8Ma的含黑云母的花岗岩、26.6Ma的含电气石黑云母的伟晶花岗岩侵入到高喜马拉雅岩系上部。这三组渐新世花岗岩具有以下特征:(1)较高的SiO_(2)、Al_(2)O_(3)、K_(2)O和Na_(2)O,A/CNK>1.0;(2)Ba、Nb、Ta、Sr和Ti的负异常;(3)略微富集轻稀土,亏损中稀土和重稀土,高度变化的Eu异常和微弱的负Nd异常;(4)均一的初始Sr-Nd同位素比值,^(87)Sr/^(86)Sr(t)=0.7463~0.7471,ε_(Nd)(t)=-15.0~-14.6。此外,含电气石黑云母的花岗岩和含电气石黑云母的伟晶花岗岩具有较高的Sr和Ba,较低的Rb/Sr比值,其Rb/Sr比值与Ba和Sr含量都无相关性,表明其为富B流体参与高喜马拉雅变沉积岩含水部分熔融作用的产物。而含黑云母的花岗岩具有较低的Sr和Ba,较高的Rb/Sr比值,且其Rb/Sr比值与Ba和Sr含量显示明显的负相关关系,表明其为变沉积岩发生脱水熔融作用的产物。综合喜马拉雅造山带已有的研究成果,得出以下认识:渐新世花岗岩的源区从下地壳基性物质转变为中地壳变泥质岩,展示了源区向上迁移的过程,并经历了一期重要的岩浆热液交代作用;渐新世深熔作用记录了造山带从缩短增厚向伸展垮塌转换阶段深部地壳的响应,从而促使了高喜马拉雅岩系的折返。 展开更多
关键词 聂拉木 渐新世花岗岩 含水部分熔融作用 高喜马拉雅岩系折返 喜马拉雅造山带
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交替饥饿下PN1/PN2系统抑制NOB研究 被引量:1
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作者 李冬 任纪元 张杰 《中国环境科学》 EI CAS CSCD 北大核心 2024年第1期202-210,共9页
为了抑制亚硝酸盐氧化菌(NOB)的生长繁殖,采用序批式反应器(SBR)运行PN1/PN2系统,设置4组反应器R1~R4,分别设置连续运行段和交替饥饿/恢复运行段.饥饿期溶解氧(DO)浓度分别设置为(1±0.5),(2±0.5),(3±0.5),(4±0.5)mg... 为了抑制亚硝酸盐氧化菌(NOB)的生长繁殖,采用序批式反应器(SBR)运行PN1/PN2系统,设置4组反应器R1~R4,分别设置连续运行段和交替饥饿/恢复运行段.饥饿期溶解氧(DO)浓度分别设置为(1±0.5),(2±0.5),(3±0.5),(4±0.5)mg/L,探讨交替周期的选取、饥饿期DO条件对功能菌活性、污泥浓度、粒径及胞外聚合物(EPS)的影响,以期实现部分硝化段的稳定运行.结果显示,相比于好氧氨氧化菌(AOB),NOB在面对饥饿时表现得更为敏感,活性衰减速率更高,恢复期前3d AOB的活性恢复速率高于NOB,因此3d的交替周期能够有效抑制NOB并保留AOB活性.采用交替周期为3d的交替饥饿/恢复策略进行70d的运行,4组反应器的亚硝酸盐氮积累率(NAR)分别达到73.36%、84.43%、91.21%、95.97%,运行过程中出现了污泥减量化的现象,但经过一段时间的适应后R1~R3的污泥浓度能够保持稳定,而R4则呈下降趋势;交替饥饿/恢复策略使系统逐渐排除沉降性能较差的絮体,而沉降性能好的污泥留在反应器内,第70d 4个反应器的污泥粒径分别达到190.69,197.56,207.69,153.56µm;环境变化刺激微生物分泌更多EPS,因此4组反应器污泥的EPS含量都呈现不同幅度的升高.实验结果表明交替饥饿/恢复策略可以刺激污泥产生有利的变化,实现有效的NOB抑制以及稳定的NO_(2)^(-)-N积累. 展开更多
关键词 短程硝化 饥饿 好氧氨氧化菌 亚硝酸盐氧化菌 活性抑制 厌氧氨氧化
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基于随机森林的发电机定子线棒局部放电图谱特征识别方法 被引量:1
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作者 胡建林 张翕 +3 位作者 宋展 向紫馨 邓鸿飞 蒋兴良 《高电压技术》 EI CAS CSCD 北大核心 2024年第3期1272-1280,共9页
发电机定子线棒局部放电的在线监测和故障诊断对于电机故障预警、故障定位和指导机组检修有重要意义。目前存在部分不同类型局部放电相似度高,模式识别方法计算时间过长的问题,需要高精度和高效的识别方法,为此提出一种基于随机森林的... 发电机定子线棒局部放电的在线监测和故障诊断对于电机故障预警、故障定位和指导机组检修有重要意义。目前存在部分不同类型局部放电相似度高,模式识别方法计算时间过长的问题,需要高精度和高效的识别方法,为此提出一种基于随机森林的定子线棒局部放电识别方法。制备了6种类型定子线棒,用特高频天线检测局部放电信号,基于相位分布局部放电(PRPD)图谱比对,提出参数幅值不对称度。基于随机森林方法识别缺陷类型,计算特征重要性,选择有效特征。最后,可视化特征相似度,与传统反向传播(BP)神经网络方法对比,验证有效性。结果表明:随机森林算法可以有效识别人工缺陷定子线棒局部放电,总体识别正确率达到93.33%。筛选半数特征后,随机森林比BP神经网络的准确率提高了10.83%,特征选择对随机森林的准确率影响很小,但识别效率大幅提高。随机森林在少量特征时识别准确率、计算时间都明显优于神经网络。幅值不对称度参数的重要性排在全部特征前1/3,具有推广价值。 展开更多
关键词 定子线棒 局部放电 在线监测 随机森林 PRPD图谱
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工艺孔对大截面部分包覆钢-混凝土组合梁受弯性能影响的试验研究 被引量:1
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作者 贾水钟 刘宏欣 +3 位作者 李亚明 孙求知 张朕磊 钱桦 《建筑结构》 北大核心 2024年第4期9-17,共9页
为了研究工艺孔对大截面部分包覆钢-混凝土组合梁(大截面PEC梁)受弯性能的影响,对5根不同构造的大截面PEC梁进行了静力试验,研究了两点加载下主次梁腹板开洞方式对大截面PEC梁试件受弯性能、延性、破坏模式等的影响规律。结果表明:静力... 为了研究工艺孔对大截面部分包覆钢-混凝土组合梁(大截面PEC梁)受弯性能的影响,对5根不同构造的大截面PEC梁进行了静力试验,研究了两点加载下主次梁腹板开洞方式对大截面PEC梁试件受弯性能、延性、破坏模式等的影响规律。结果表明:静力荷载作用下,各个试件均表现出良好的延性,腹部开孔对试件承载力和截面刚度有一定的削弱作用。型钢主钢件的应变与混凝土的应变沿截面高度方向均大致呈线性变化,符合平截面假定。按《部分包覆钢-混凝土组合结构技术规程》(T/CECS 719—2020)计算得到的开工艺孔的大截面PEC梁抗弯承载力与试验值误差较小,受尺寸效应影响不大,所采用计算公式安全可靠。 展开更多
关键词 大截面部分包覆钢-混凝土组合梁 工艺孔 破坏模式 受弯承载力 延性
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