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鱼油是n-3多不饱和脂肪酸的重要来源，为明确鱼油中多不饱和脂肪酸的位置分布，采用气相色谱法测定了4种天然鱼油和3种加工鱼油的总脂肪酸组成，并采用核磁共振碳谱（13C-NMR）分析其多不饱和脂肪酸的位置分布，同时运用Novozym 435醇解结合气相色谱分析了4种天然鱼油中甘油三酯上饱和脂肪酸（SFA）和单不饱和脂肪酸（MUFA）的位置分布。结果表明：加工鱼油中二十二碳六烯酸（DHA）含量为28.43%~76.63%，二十碳五烯酸（EPA）含量为12.72%~5637%，总体含量均高于天然鱼油；天然鱼油中DHA主要分布在sn-2位，sn-2 DHA相对含量为50.39%~63.71%，而加工鱼油中DHA则处于随机分布状态，sn-2 DHA相对含量为28.78%~36.76%；不同天然鱼油中SFA和MUFA没有明确分布规律。综上，鱼油的加工工艺可以提高DHA的含量但是改变了其在甘油三酯碳骨架的分布。Fish oil is a rich source of n-3 polyunsaturated fatty acids (PUFA). In order to clarify the positional distribution of PUFA in fish oil, gas chromatography (GC) was used to determine the total fatty acid composition of 4 kinds of natural fish oil and 3 kinds of processed fish oil, and 13C-nuclear magnetic resonance (13C-NMR) was used to analyze the positional distribution of PUFA. At the same time, the positional distribution of saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) on triacylglycerol (TAG) in 4 natural fish oils were analyzed using the alcoholysis of Novozym 435 combined with GC. The results showed that the contents of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) in processed fish oil generally higher than that in natural fish oil, with DHA content of 28.43%-76.63% and EPA content of 12.72%-5637%. DHA in natural fish oils was mainly esterified at the sn-2 position (relative content of sn-2 DHA 50.39%-63.71%), while that in processed fish oils was in a random distribution state (relative content of sn-2 DHA 28.78%-36.76%). There was no clear distribution pattern of SFA and MUFA in different natural fish oils. In conclusion, the processing technology of fish oil can increase the content of total DHA, but change the positional distribution of DHA on the TAG glycerol backbone.

The parallel-serial robot motion mechanism,compared to the single parallel mechanism,the working space can be largely increased and so as its deflexion capacity,there for,its application foreground is broad. A positional forward analysis solution of 2（3-RPS） parallel-serial robot motion mechanism is presented. Firstly,the position coordinates of spherical joints on the upper platform of 3-RPS parallel mechanism are derived based on its structural characteristics,and then,a set of equations are listed according to the fixed side value of motion platform of each parallel mechanism,using iterative transformation method,a 16 order equation with one unknown variable is gained. All its positional forward solutions can be precisely derived after the structure parameters of the parallel-serial mechanism are determined. At last,the numerical example is presented,and 32 positional forward solutions are gained at the specific structure parameters.

为丰富弱轴半刚性连接刚度数据库、研究端板连接节点刚度对钢框架结构抗震性能的影响规律,进行了弱轴端板连接节点的半刚性性能试验研究,得到了连接节点的弯矩-转角关系曲线,并借助有限元分析软件SAP2000对空间钢框架结构进行了抗震性能分析,得到了4个空间结构模型在多遇地震和罕遇地震下的结构时程位移曲线和层间位移角。研究表明:弱轴外伸端板连接节点刚度约为相同尺寸节点强轴方向的30%,节点变形能力较强,具有良好的耗能能力;节点刚度对结构的前三阶周期尤其是基本周期影响很大;端板连接钢框架在小震、大震下层间位移角均能满足规范要求且具有良好的抗震性能和抗连续倒塌能力。

结合支撑和钢板剪力墙的特点,提出了两端连接偏心支撑钢板剪力墙的结构形式,采用ANSYS有限元软件进行了弹性屈曲分析,重点研究了内填板的高厚比、宽高比、柱弹性刚度对弹性屈曲系数和屈曲荷载的影响。结果表明,支撑能够起到显著提高屈曲荷载的作用。高厚比和宽高比是影响两端连接偏心支撑的钢板墙的弹性屈曲荷载的主要因素。为进一步研究两端连接偏心支撑钢板剪力墙的多道抗震设防奠定了理论基础。

本文用斜拉杆简化模型分析了钢板墙从弹性屈曲到拉力带全部屈服的受力全过程。考虑了真实的拉力带倾角、塑性变形系数和屈服后阶段弹模折减等因素影响,用斜拉杆模型模拟了拉力带的受力过程,推导了斜拉杆初始屈服应力、极限应力、钢板墙剪力和位移计算公式,得到了钢板墙的弹塑性荷载-位移曲线,最后与试验资料比较验证了公式的有效性。

针对《门式刚架轻型房屋钢结构技术规程》 （CECS10 2 :2 0 0 2 ）中刚架柱计算长度系数取值上存在的一些问题———适用范围小 （规定限于屋面坡度很小时公式适用 ） ,而且未考虑斜梁内轴力的不利影响 ;本文利用有限元法编程对柱脚铰接及刚接有侧移楔形变截面单跨门式刚架的整体稳定性进行了大量算例分析 ,提出了实用的确定楔形刚架柱的计算长度系数的方法

文章介绍了适合于在当前技术条件下的新交换技术—光突发交换 ,并对光突发交换中的各种冲突解决协议进行了阐述和对比 .

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Objective To investigate the clinical diagnostic value of transthoracic echocardiography (TTE) and transthoracic right heart contrast echocardiography (RHCE) for patent foramen ovale (PFO) and the effect of Valsalva maneuver on the detection rate of PFO. Methods A retrospective analysis was conducted on the imaging data of 395 patients with suspected PFO who visited this hospital from March 2021 to January 2023. All patients underwent TTE,RHCE in resting state, and RHCE under Valsalva maneuver. Results The detection rate of PFO by RHCE was higher than that by TTE,and the detection rate of PFO by RHCE under Valsalva maneuver was higher than that in resting state, with statistically significant differences (P＜0. 05). The grade of right-to-left shunt detected by RHCE under Valsalva maneuver was higher than that in resting state, with a statistically significant difference (P＜0. 05). The number of cardiac cycles required for the left atrium to become visible after the right atrium was fully visualized with agitated saline contrast in RHCE under Valsalva maneuver was smaller than that in resting state, with a statistically significant difference (P＜0. 05). Conclusion RHCE and Valsalva maneuver are helpful in the detection of PFO. [ABSTRACT FROM AUTHOR]

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The experiment aims to explore the optimal harvesting time for alfalfa in the Tumochuan Plain, providing scientific reference for the large-scale production and application of alfalfa. The experiment was set up with three treatments: bud initiation, early flowering, and full bloom, with each treatment replicated three times. The experiment measure the yield traits, nutritional quality, and economic benefits of alfalfa (WL319HQ) at different harvesting times in the Tumochuan Plain. The results showed that when alfalfa was harvested at the bud stage, the annual dry hay yield was 13 011.60 kg/hm². The contentrations of CP, NDF, and ADF were 20.69%DM, 36.91%DM, and 26.64%DM, respectively, with an RFV of 172.11, and the income ranged from 16 131.34 to 20 034.83 yuan/hm². When harvested at the early flowering stage, the annual dry hay yield was 12 829.81 kg/hm², with CP, NDF, and ADF contentrations of 18.55%DM, 41.03%DM, and 30.70%DM, respectively, an RFV of 147.78, and the income ranged from 11 791.53 to 15, 640.47 yuan/hm². When harvested at the full flowering stage, the annual dry hay yield was 14 444.64 kg/hm², with CP, NDF, and ADF contentations of 16.80%DM, 45.82%DM, and 35.57%DM, respectively, an RFV of 124.40, and the income was less than 9 889.27 yuan/hm². The research indicates that alfalfa harvested at the bud stage on the Tumochuan Plain has higher nutritional value and economic benefits. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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To investigate the expression of mitosis-associated kinase 2 (NEK2) and erythropoietin-producing hepatocyte receptor A5 (EPHA5) in non-small cell lung cancer (NSCLC) tissues, and to analyze their relationship with clinicopathological features, epidermal growth factor receptor (EGFR) mutation and prognosis. 151 NSCLC patients who were diagnosed and treated in our hospital from October 2019 to October 2020 were selected as research objects, the cancer tissues and adjacent normal tissues (more than 5cm from the cancer tissues) were taken during the operation. The expression of EGFR gene was detected by real-time fluorescence quantitative polymerase chain reaction (RT-PCR). The expression of NEK2 and EPHA5 in cancer tissues and adjacent tissues was detected by immunohistochemistry. The expression of NEK2 and EPHA5 in cancer tissues and adjacent tissues was compared. The expression of NEK2 and EPHA5 in NSCLC patients with different clinicopathological features was analyzed. The expression of NEK2 and EPHA5 in different EGFR mutant and wild type was analyzed. The prognosis of NSCLC patients with different NEK2 and EPHA5 expression were analyzed by Kaplan-Meier survival curve. Compared with adjacent tissues, the positive expression rates of NEK2 and EPHA5 in cancer tissues were significantly higher (all P<0.05). The positive expression rates of NEK2 and EPHA5 in patients with TNM stage IIIA, lymph node metastasis and tumor diameter ≥ 5 cm were significantly higher than those in patients with TNM stage I～II, no lymph node metastasis and tumor diameter<5 cm (all P<0.05). The positive expression rates of NEK2 and EPHA5 in EGFR mutant group were significantly higher than those in EGFR wild type group (all P<0.05). The 3-year overall survival rate (OS) in NEK2 positive expression group and negative expression group were 40.40% (40/99) and 57.69% (30/52) respectively. The 3-year OS in EPHA5 positive expression group and negative expression group were 41.90% (44/105) and 56.52% (26/46) respectively, the cumulative survival of patients in each negative expression group were significantly higher than those in positive expression group (P<0.05). The positive expression rates of NEK2 and EPHA5 in NSCLC cancer tissues are increase, which are relate to TNM stage IIIA, lymph node metastasis, tumor diameter, and may also lead to EGFR mutation and poor prognosis [ABSTRACT FROM AUTHOR]

The actual industrial process often presents strong nonlinearity and strong coupling in operation. How to control the system quickly and accurately under complex working conditions is a current research focus. In this paper, an identification of Wiener model for nonlinear systems based on correlation analysis is studied. The Wiener nonlinear model consists of a dynamic linear subsystem and a static nonlinear subsystem in series, and the dynamic linear subsystem and the static nonlinear subsystem are established by using time-delay state space model and neural fuzzy model respectively, and the Wiener nonlinear model is separated and identified by using the designed combined signal. Firstly, the time-delay state space model is transformed into a transfer function model by using the properties of the backward operator, and the parameters of the dynamic linear subsystem are identified by correlation analysis method under the action of Gaussian signal, which solves the unmeasurable problem of intermediate variables in Wiener model. Secondly, in order to improve the accuracy and convergence speed of the identification model, a recursive stochastic gradient method with forgetting factor is derived to estimate the parameters of the static nonlinear subsystem. The proposed nonlinear Wiener model identification method is applied to continuous stirred tank reactor. The simulation results show that the proposed Wiener model identification method can effectively identify the continuous stirred tank reactor system and achieve better control effect. [ABSTRACT FROM AUTHOR]

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