天然气提氦联产LNG新工艺特性及适应性分析

目的为降低利用单一低温法从天然气中提氦的工艺设备投资及能量损耗,提出一种新型天然气提氦联产LNG工艺。方法以国内某气田低含氦原料气数据为基础,对该新工艺的特性及适应性进行了模拟分析,并通过遗传算法对混合制冷剂制冷循环进行了优化。结果①通过特性分析可知,节流前温度越低、节流压力越高,闪蒸罐对氦气的浓缩作用越好,同时可生产摩尔分数达到99.9%的高纯氮气产品,并自产液氮产品;②新工艺对原料气中氮气、氦气纯度变化及原料气压力均有很强的适应性,原料气压力越高、氮气和氦气纯度越低,压缩机轴功率越低;③通过特性及适应性分析、混合制冷剂制冷工艺参数优化可得闪蒸罐节流前温度为-150℃,节流压力为350 kPa,提氦塔压力为3200 kPa,脱氮塔和提氦塔塔板数均为12块,混合制冷剂压缩机一级和二级最优增压压力分别为1341 kPa和2767 kPa,混合制冷剂循环量为1722.7 kmol/h,压缩机总轴功率为3765 kW,冷却水用量为6474 t/d,综合能耗及单位能耗分别为1097216.00 MJ/d、3.66 MJ/m^(3)。结论该新型工艺的氦气回收率超过98%,粗氦摩尔分数高于70%,且可自产制冷剂,并得到高纯氮气和液氮产品,对原料气气质条件适应性好。

酸法破壁条件对法夫酵母虾青素提取效果的影响

为了评价酸法破壁在法夫酵母虾青素提取中的应用价值,从酸的种类、酸的浓度、液料比、破壁温度及时间等方面研究了条件因子对破壁后法夫酵母虾青素提取的影响并对破壁条件进行了优化。试验结果表明:乳酸比盐酸和醋酸更适合用于法夫酵母的破壁处理;酸的浓度、破壁温度等因素对虾青素的提取得率影响较大,而酸处理时间和液料比对虾青素的提取得率影响不大。用正交试验方法得到优化的乳酸破壁法夫酵母的条件为:乳酸浓度6mol/L、破壁温度30℃、破壁时间5min、酸加量15mL/g(干菌体),优化后虾青素的提取得率为1374.7μg/g(干菌体),总类胡萝卜素的提取得率为1709.9μg/g(干菌体),提取物中虾青素占总类胡萝卜素80.4%。优化的破壁条件温和,不会引起残留毒性,能获得良好的虾青素提取效果,具有较好的工业应用前景。

基于藤崎模型的汉语语音基频轮廓的参数提取

基频轮廓就是基频随时间变化的曲线，刻画了汉语中最主要的韵律特征—声调和语调的变化趋势．而藤崎模型则是由日本东京大学藤崎博也教授建立的一种韵律模型，可以用来非常好地逼近汉语语音的基频轮廓（１）．本文提出了一种基于该模型的从汉语单音节的基频轮廓中提取参数的方法．我们首先采用基于小波变换的基音检测技术（３）获取非常准确的给定单字的各基频值，并连接形成基频轮廓，然后根据最小均方误差准则，用藤崎模型来拟合各基频点，最后分析得出模型的最优化参数，作为此基频轮廓的参数．

Joint eigenvalue estimation by balanced simultaneous Schur decomposition

The problem of joint eigenvalue estimation for the non-defective commuting set of matrices A is addressed. A procedure revealing the joint eigenstructure by simultaneous diagonalization of. A with simultaneous Schur decomposition （SSD） and balance procedure alternately is proposed for performance considerations and also for overcoming the convergence difficulties of previous methods based only on simultaneous Schur form and unitary transformations, it is shown that the SSD procedure can be well incorporated with the balancing algorithm in a pingpong manner, i. e., each optimizes a cost function and at the same time serves as an acceleration procedure for the other. Under mild assumptions, the convergence of the two cost functions alternately optimized, i. e., the norm of A and the norm of the left-lower part of A is proved. Numerical experiments are conducted in a multi-dimensional harmonic retrieval application and suggest that the presented method converges considerably faster than the methods based on only unitary transformation for matrices which are not near to normality.

A Novel Technique of Parameter Extraction for Short Channel Length LDD MOSFETs

A novel parameter extraction technique suitable f or short channel length lightly-doped-drain (LDD) MOSFET's is proposed which seg ments the total gate bias range,and executes the linear regression in every subs ections,yielding the gate bias dependent parameters,such as effective channel le ngth,parasitic resistance,and mobility,etc.This method avoids the gate bias rang e optimization,and retains the accuracy and simplicity of linear regression.The extracted gate bias dependent parameters are implemented in the compact I-V model which has been proposed for deep submicron LDD MOSFET's.The good agreemen ts between simulations and measurements of the devices on 0.18μm CMOS technolo gy indicate the effectivity of this technique.

Supercritical Fluid Extraction of Essential Oil from Dry Rhizome of Ligusticum chuanxiong Hort and Their Characterization by GC/MS

Supercritical fluid extraction (SFE) of essential oil from dry rhizome ofLigusticum chuanxiong Hort was developed. GC/MS was used for the determination of the composition ofessential oil. Forty-four compounds were identified. The conventional extraction method wasconducted in parallel for comparison. The extracts were qualitatively compared by GC/MS. The yieldsof SFE and steam distillation-extraction were 4.16 % ( v/w) and 0.8 % ( v/w), respectively.Application of SFE of zessential oil from dry rhizome of Ligustiaan chuanxiong Hort was preferable.

On Several Propositions of Hopf Bundle S^3

The author gives out the testification of several relevant propositions of Hopf main fibre S 3; and points out that the lifting on the main bundle of Laplace operator in the base manifold S 2 is the Laplace operator in the main fibre bundle S 3 and that the embedding surface of main bundle has such properties as having fixed point, etc.

Integrative Extraction of Ergosterol, （1→3）-α-D-Glucan and Chitosan from Penicillium chrysogenum Mycelia

Abstract Ergosterol,（1→3）-α-D-glucan and chitosan are important biomaterials. In this research, a process has been developed to integratively extract ergosterol, （1→3）-α-D-glucan, and chitosan from Penicillium chrysongenum mycelium. First the mycelia are pretreated with 0.1mol·L^-1 of NaOH. After recovery by centrifugation the solid portion is made to undergo saponification and deacetylation reactaons by addition of 2mol·L^-1 NaOH and et anol.After reaction, extraction is carried out by addition of petroleum ether, which separates the reaction mixture into two phases. The upper layer of petroleum ether contains extracted ergosterol, and the .bottom layer of NaOH solution contains （1→3）-α-DEglucan; the chitosan is on the mycelia residuum. After isolation, the recovery yield of ergosterol is 0.52% of dry mycelium. That of （1→3）-α-D-glucan is about 8.2%; and chitosan is 5.7% with 86% deacetylation. The compositions have been characterized by 1R, HPLC analyses.

Improved pedestrian detection with peer AdaBoost cascade

Focusing on data imbalance and intraclass variation,an improved pedestrian detection with a cascade of complex peer AdaBoost classifiers is proposed.The series of the AdaBoost classifiers are learned greedily,along with negative example mining.The complexity of classifiers in the cascade is not limited,so more negative examples are used for training.Furthermore,the cascade becomes an ensemble of strong peer classifiers,which treats intraclass variation.To locally train the AdaBoost classifiers with a high detection rate,a refining strategy is used to discard the hardest negative training examples rather than decreasing their thresholds.Using the aggregate channel feature(ACF),the method achieves miss rates of 35%and 14%on the Caltech pedestrian benchmark and Inria pedestrian dataset,respectively,which are lower than that of increasingly complex AdaBoost classifiers,i.e.,44%and 17%,respectively.Using deep features extracted by the region proposal network(RPN),the method achieves a miss rate of 10.06%on the Caltech pedestrian benchmark,which is also lower than 10.53%from the increasingly complex cascade.This study shows that the proposed method can use more negative examples to train the pedestrian detector.It outperforms the existing cascade of increasingly complex classifiers.

Steroids from green alga Chaetomorpha basiretorsa Setchell

Six steroids have been isolated from ethanolic extract of green alga Chaetomorpha basiretorsa Setchell by a combination of repeated normal phase silica gel and Sephadex LH-20 gel column chromatography as well as recrystallization. Using spectroscopic methods including MS and NMR, their structures were determined as β-1awsaritol （1）, saringosterol （2）, 24-hydroperoxy-24-vinyl- cholesterol （3）, β-stigmasterol （4）, stigmast-4-en-3α, 6β-diol （5）, 29-hydroxystigmasta-5, 24 （28）-dien-3β-ol （6）. All these compounds were obtained from this genus for the first time and they were inactive （IC50〉10μg/ml） against KB, Bel-7402, PC-3M, Ketr 3 and MCF-7 cell lines.

Identification of Volatile Compounds in Codfish(Gadus) by a Combination of Two Extraction Methods Coupled with GC-MS Analysis

Codfish is a kind of abyssal fish species with a great value in food industry. However, the flavor of codfish, especially the unpleasant odor, has caused serious problems in its processing. To accurately identify the volatile compounds in codfish, a combination of solid phase micro-extraction(SPME) method and simultaneous distillation extraction(SDE) method was used to extract the volatiles. Gas chromatography-mass spectrometry(GC-MS) along with Kovats indices(KI) and authentic standard compounds were used to identify the volatiles. The results showed that a total of 86 volatile compounds were identified in codfish, of them 24 were extracted by SDE, 69 compounds by SPME, and 10 compounds by both SDE and SPME. Seventy volatile compounds were found to have specific odors, of them 7 typical compounds contributed significantly to the flavor of codfish. Alcohols(i.e.,(E)-2-penten-1-ol and 2-octanol), esters(i.e., ethyl butyrate and methyl geranate), aldehydes(i.e., 2-dodecenal and pentadecanal) contributed the most to fresh flavor while nitrogen compounds, sulphur compounds, furans, as well as some ketones(i.e., 2-hydroxy-3-pentanone) brought unpleasant odor, such as fishy and earthy odor. It was indicated that the combination of multiple extraction methods and GC-MS analysis can enhance the accuracy of identification, and provide a reference for the further study on flavor of aquatic products.

To Complete Mourning by Becoming Specters＂ The Mutualized Coming-to-Be in The Red Violin

This essay enacts a dialogue between Francois Girard＇s film The Red Violin （1998） and Jacques Derrida＇s contemplations on ＂memory,＂ ＂spectrality＂ and ＂the work of mourning＂ to envision the possibility of opening a hopeful condition of being for those who suffer from loss. In The Red Violin, Girard＇s cinematic experiments apply techniques of montage and of repetitive musical theme, practicing intertextuality of non-chronological stories by paralleling various memories of each individual character, blurring the biological and metaphorical boundaries between the living and non-living, and highlighting the fateful interrelations among time, space and different characters＇ life experiences. In this vein, the memories and beings of both the living and the dead are tightly woven together while reproduced--or further, relived--in temporal, spatial and trans-individual dynamics. Reversing the negative imaginaries of loss and death, both Derrida and The Red Violin agree with a messianic work of mourning by exploring the powerful potentiality of spectrality that manifests a way to mutualize the subject/ other, the living/non-living, into a promised being, thus gesturing towards an infinite future.

Relevance-based content extraction of HTML documents

Content extraction of HTML pages is the basis of the web page clustering and information retrieval,so it is necessary to eliminate cluttered information and very important to extract content of pages accurately.A novel and accurate solution for extracting content of HTML pages was proposed.First of all,the HTML page is parsed into DOM object and the IDs of all leaf nodes are generated.Secondly,the score of each leaf node is calculated and the score is adjusted according to the relationship with neighbors.Finally,the information blocks are found according to the definition,and a universal classification algorithm is used to identify the content blocks.The experimental results show that the algorithm can extract content effectively and accurately,and the recall rate and precision are 96.5% and 93.8%,respectively.

Automatic Horizontal Road Design Information Extraction from Georeferenced Polygonals： A Brazilian Federal Highway Network Study

Road geometric design data are a vital input for diverse transportation studies. This information is usually obtained from the road design project. However, these are not always available and the as-built course of the road may diverge considerably from its projected one, rendering subsequent studies inaccurate or impossible. Moreover, the systematic acquisition of this data for the entire road network of a country or even a state represents a very challenging and laborious task. This study＇s goal was the extraction of geometric design data for the paved segments of the Brazilian federal highway network, containing more than 47,000 km of highways. It presents the details of the method＇s adoption process, the particularities of its application to the dataset and the obtained geometric design information. Additionally, it provides a first overview of the Brazilian federal highway network composition （curves and tangents） and geometry.

Inhibition characteristics of circulating current in parallel inverter driving system of mine hoist

This research investigated the outputting circulation current inhibition characteristic which are controlled by the instantaneous feedback voltage in inverter parallel driving of the mine hoist. We established a transfer function of the parallel inverters controlled by the close-loop adjustment of instantaneous voltage feedback. The influence of the parameters of the close-loop feedback circuit to the inhibition effects to the outputting circulation current is observed. After analyzing the circulating current inhibition characteristics, the proportion integration （PI） controller is introduced into the close-loop adjustment by instantaneous voltage feedback. The characteristics equation is gained to determine the PI parameters by drawing the Bode plots. The inhibition effects of the proposed controller are examined by the established simulation model of parallel inverter system. The harmonic distortion rate at the outputting voltage frequency value of 4, 10, 20, 41 and 50 Hz, are all lower than 2.32 % by the instantaneous outputting voltage feedback.

Design of cost allocation rule for joint replenishment with controllable lead time

To encourage retailers to form cooperative alliances to jointly replenish inventory,considering that the supplier provides a flexible lead time and quantity discount to retailers,a model of average total cost per unit time of periodic joint replenishment is constructed,and an approximate algorithm,which can satisfy the requirement of any given precision,is given.The cost allocation rule in the core of the joint replenishment game is designed based on the cooperative game theory.The numerical experiment results show that the proposed algorithm can quickly solve the joint replenishment problem when the item number is not greater than 640.The retailer's cost saving rate is always greater than 0,and it increases with the increase in quantity discount and fixed cost after adopting the given cost allocation rule.With the increase in the safety stock level,the retailer's cost saving rate increases first and then decreases;and the retailer's cost saving rate increases with the increase in the size of the alliance,but it decreases as the number of product category increases.The proposed cost allocation rule can reduce the retailer's cost up to 20%,which is conducive to forming a cooperative coalition.

The Single Training Sample Extraction of Visual Evoked Potentials Based on Wavelet Transform

Based on the good localization characteristic of the wavelet transform both in time and frequency domain, a de-noising method based on wavelet transform is presented, which can make the extraction of visual evoked potentials in single training sample from the EEG background noise in favor of studying the changes between the single sample response happen. The information is probably related with the different function, appearance and pathologies of the brain. At the same time this method can also be used to remove those signal’s artifacts that do not appear with EP within the same scope of time or frequency. The traditional Fourier filter can hardly attain the similar result. This method is different from other wavelet de-noising methods in which different criteria are employed in choosing wavelet coefficient. It has a biggest virtue of noting the differences among the single training sample and making use of the characteristics of high time frequency resolution to reduce the effect of interference factors to a maximum extent within the time scope that EP appear. The experiment result proves that this method is not restricted by the signal-to-noise ratio of evoked potential and electroencephalograph (EEG) and even can recognize instantaneous event under the condition of lower signal-to-noise ratio, as well as recognize the samples which evoked evident response more easily. Therefore, more evident average evoked response could be achieved by de-nosing the signals obtained through averaging out the samples that can evoke evident responses than de-nosing the average of original signals. In addition, averaging methodology can dramatically reduce the number of record samples needed, thus avoiding the effect of behavior change during the recording process. This methodology pays attention to the differences among single training sample and also accomplishes the extraction of visual evoked potentials from single trainings sample. As a result, system speed and accuracy could be improved to a great extent if this methodology is applied to brain-computer interface system based on evoked responses.

Evaluating the performances of accelerated-solvent extraction, microwave-assisted extraction, and ultrasonic-assisted extraction for determining PCBs, HCHs and DDTs in sediments

Three extraction techniques have been recently used for the quantitative extraction of semi-volatile organic pollutants in sediments, i.e. accelerated solvent extraction （ASE）, microwave assisted extraction （MAE） and ultrasonic assisted extraction （UAE）. However, their extraction efficiencies have rarely been quantitatively compared using rigorous mathematical methods. In this paper, one-way analysis of variance （ANOVA） was employed to evaluate the performance of ASE, MAE and UAE in the overall extraction of PCBs, DDTs and HCHs by analysis of their recoveries from the Standard Reference Material IAEA-417, a sediment sample certified by many international laboratories. Conclusions were drawn at a significance level of P〈 0.05. No significant differences were found among the mean values for method recoveries using ASE, MAE and UAE. The mean values for real recoveries using ASE and MAE were nearly identical, but the real recovery using UAE was much lower. The concentrations of all PCBs, DDTs and HCHs except for CB52 and o,p＇-DDT using UAE were the lowest. Comparing the results obtained using ASE with MAE, the concentrations of CB28, CB52, CB138, ct-HCH, [3-HCH, p,p＇-DDE and p,p＇-DDD were nearly identical, while the concentrations of other compounds were significantly different. Based on the low recoveries, it was concluded that UAE is a relatively inefficient extraction method, while ASE and MAE are equivalent methods. Taking into consideration the relative standard deviation （RSD） values, solvent volume, extraction time, and purchasing costs of the apparatus, MAE was considered superior to ASE for extraction of PCBs, DDTs and HCHs.

Effects of Shenlian Extracts (参莲提取物) on Atherosclerosis by Inhibition of the Inflammatory Response

Objective: Inflammation plays a critical role in atherosclerosis, and this inflammatory reaction is being intensively studied. Shenlian Extracts (参莲提取物), an active ingredient of Chinese medicinal herbs, is believed to have multiple therapeutic and preventive effects against human vascular diseases, including atherosclerosis. Our work investigated whether Shenlian Extracts serves as an anti-inflammatory agent during atherogenesis. Methods: We established a model of atherosclerosis in rabbits using balloon angioplasty and a high cholesterol diet. The effects of Shenlian Extracts on vessel structure and inflammation were assessed by hematoxylin-eosin staining of the femoral artery, measurement of inflammation-related factors in serum or vascular tissue, and radioimmunoassay. Enzyme linked immunosorbent assays (ELISA), flow cytometry and western blots were also performed. Results: We show that oral pre-treatment with Shenlian Extracts suppressed the pathological changes associated with atherosclerosis and that graded doses of Shenlian Extracts reduced total serum levels of cholesterol (90, 180 and 360 mg/kg), triglyceride (180 and 360 mg/kg), and LDL-c (90, 180 mg/kg). Various doses of Shenlian Extracts reduced serum content of TNF-α (180 and 360 mg/kg), CRP (90, 180 and 360 mg/kg) and IL-8 (360 mg/kg) (P<0.05), but led to no significant changes in IL-1β levels. Treatment with Shenlian Extracts also significantly reduced VCAM-1 levels (90 and 360 mg/kg) and IGF-1 levels (90 and 180 mg/kg) in vascular tissue but had no significant effect on ICAM-1 and MCP-1 levels. Finally, Shenlian Extracts significantly reduced the abnormal expression of CD18 in monocytes in a dose-dependent manner. Conclusion: These results suggest that Shenlian Extracts may play a direct role in preventing and treating atherogenesis by inhibiting the inflammatory reaction, providing insights into the possible mechanism underlying the anti-atherosclerotic actions of Shenlian Extracts.

Clinical value of Tongguanteng(Radix seu Herba Marsdeniae Tenacissimae) extract combined with chemotherapy in the treatment of advanced non-small cell lung cancer： a Meta-analysis

OBJECTIVE: To investigate the clinical efficacy and safety of Tongguanteng(Radix seu Herba Marsdeniae Tenacissimae) extract combined with chemotherapy in the treatment of advanced non-small celllung cancer(NCSLC) compared with chemotherapy alone.METHODS: Databases including Chinese National Knowledge Infrastructure, China Biology Medicine Disc, Wanfang, and MEDLINE were searched until April 1, 2014. Two assessors independently reviewed each trial. The primary outcome was the effective rate(ER) of Tongguanteng(Radix seu Herba Marsdeniae Tenacissimae) extract combined with chemotherapy. The secondary outcomes included quality of life improvement rate(QOLIR) and adverse reactions. Statistical calculations were performed by using Cochrane Collaboration Review Manager 5.2.RESULTS: A total of 888 patients from 15 studies,13 randomized controlled trials(RCT) and two controlled clinical trials, were included. Compared with chemotherapy alone, Tongguanteng(Radix seu Herba Marsdeniae Tenacissimae) extract plus chemotherapy significantly improved ER [Risk ratio(RR) =1.32, 95% CI,(1.14, 1.54)](based on 15 studies) and QOLIR [RR = 2.04, 95% CI,(1.69, 2.47)](based on 13studies). Compared with chemotherapy alone,Tongguanteng(Radix seu Herba Marsdeniae Tenacissimae) extract plus chemotherapy significantly inhibited chemotherapy-induced white blood cell decline [RR = 0.79, 95% CI,(0.70, 0.90)(based on 10 studies), chemotherapy-induced platelet decline[RR = 0.77, 95% CI,(0.60, 0.98)](based on 8 studies),and significantly alleviated nausea and vomiting(NV) [RR = 0.83, 95% CI,(0.71, 0.97)](based on 7studies). There was no significant difference in hemoglobin decline between the two therapies [RR =0.88, 95% CI,(0.70, 1.09)](based on 6 studies).CONCLUSION: This Meta-analysis suggests that Tongguanteng(Radix seu Herba Marsdeniae Tenacissimae) extract combined with chemotherapy may be more efficacious in the treatment of advanced NSCLC than chemotherapy alone. This effect includes enhancing ER and QOLIR, and weakening chemotherapy toxicity. However, large-scale RCTs are required to further investigate the short- and long-term effects of Tongguanteng(Radix seu Herba Marsdeniae Tenacissimae) extract.