以后再也不用擔心寫爬蟲ip被封，不用擔心沒錢買代理ip的煩惱了 在使用python寫爬蟲時候，你會遇到所要爬取的網站有反爬取技術比如用同一個IP反復爬取同一個網頁，很可能會被封。如何有效的解決這個問題呢？我們可以使用代理ip，來設置代理ip池。 現在教大家一個可獲取大量免費有效快速的代理ip方法，我們訪問西刺免費代理ip網址 這里面提供了許多代理ip，但是我們嘗試過后會發現并不是每一個都是有效的。所以我們現在所要做的就是從里面提供的篩選出有效快速穩定的ip。 以下介紹的免費獲取代理ip池的方法： 優點：免費、數量多、有效、速度快 缺點：需要定期篩選 主要思路： 從網址上爬取ip地址并存儲 驗證ip是否能使用-（隨機訪問網址判斷響應碼） 格式化ip地址 代碼如下： 1.導入包 import requests from lxml import etree import time 1 2 3 2.獲取西刺免費代理ip網址上的代理ip def get_all_proxy(): url = 'http://www.xicidaili.com/nn/1' headers = { 'User-Agent': 'Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36', } response = requests.get(url, headers=headers) html_ele = etree.HTML(response.text) ip_eles = html_ele.xpath('//table[@id="ip_list"]/tr/td[2]/text()') port_ele = html_ele.xpath('//table[@id="ip_list"]/tr/td[3]/text()') proxy_list = [] for i in range(0,len(ip_eles)): proxy_str = 'http://' + ip_eles[i] + ':' + port_ele[i] proxy_list.append(proxy_str) return proxy_list 1 2 3 4 5 6 7 8 9 10 11 12 13 14 3.驗證獲取的ip def check_all_proxy(proxy_list): valid_proxy_list = [] for proxy in proxy_list: url = 'http://www.baidu.com/' proxy_dict = { 'http': proxy } try: start_time = time.time() response = requests.get(url, proxies=proxy_dict, timeout=5) if response.status_code == 200: end_time = time.time() print('代理可用：' + proxy) print('耗時:' + str(end_time - start_time)) valid_proxy_list.append(proxy) else: print('代理超時') except: print('代理不可用--------------->'+proxy) return valid_proxy_list 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 4.輸出獲取ip池 if __name__ == '__main__': proxy_list = get_all_proxy() valid_proxy_list = check_all_proxy(proxy_list) print('--'*30) print(valid_proxy_list) 1 2 3 4 5 技術能力有限歡迎提出意見，保證積極向上不斷學習 ———————————————— 版權聲明：本文為CSDN博主「彬小二」的原創文章，遵循 CC 4.0 BY-SA 版權協議，轉載請附上原文出處鏈接及本聲明。 原文鏈接：https://blog.csdn.net/qq_39884947/article/details/86609930
上傳時間： 2019-11-15
上傳用戶：fygwz1982
This research work aims at eliminating the off-chip RF SAW filters from fre- quency division duplexed (FDD) receivers. In the first approach, a monolithic passive RF filter was constructed using on-chip capacitors and bondwire inductors. The bond- wire characteristics were studied in details and the effect of mutual inductive coupling between the bondwires on the filter performance was analyzed. Based on that, a bond- wire configuration was proposed to improve the frequency response of the filter. The filter was implemented in 0.18 μm CMOS process for WCDMA applications.
標簽： Interference Mitigation Techniques
上傳時間： 2020-05-27
上傳用戶：shancjb
The first question most readers of an O’Reilly book might ask is about the choice of the cover animal. In this case, “why a duck?” Well, for the record, our first choice was a unicorn decked out in glitter and a rainbow sash. That response always gets a laugh (we are sure you just giggled a little), but it also brings to the surface a common perception of software-defined networks among many expe‐ rienced network professionals. Although we think there is some truth to this perception, there is certainly more meat than myth to this unicorn.
標簽： Networks Software Defined SDN
上傳時間： 2020-06-01
上傳用戶：shancjb
It has been said that the move from narrowband to broadband access is the second revolution for the Internet — ‘broadband is more bandwidth than you can use’. Once users have experienced broadband access there is no turning back. A whole new world of applications and services becomes possible. No longer is it the ‘world- wide wait’. The speed of response and visual quality enabled by broadband finally allows the Internet to reach its true potential.
上傳時間： 2020-06-06
上傳用戶：shancjb
n its Framework and Roadmap for Smart Grid Interoperability Standards, the US National Institute of Standards and Technology declares that a twenty-first-century clean energy economy demands a twenty-first-century electric grid. 1 The start of the twenty-first century marked the acceleration of the Smart Grid evolution. The goals of this evolution are broad, including the promotion of widespread and distributed deployment of renewable energy sources, increased energy efficiency, peak power reduction, automated demand response, improved reliability, lower energy delivery costs, and consumer participation in energy management.
上傳時間： 2020-06-07
上傳用戶：shancjb
n present power system, the engineers face variety of challenges in planning, construction and operation. In some of the problems, the engineers need to use managerial talents. In system design or upgrading the entire system into automatic control instead of slow response of human operator, the engineers need to exercise more technical knowledge and experience. It is principally the engi- neer’s ability to achieve the success in all respect and provide the reliable and uninterrupted service to the customers. This chapter covers some important areas of the traditional power system that helps engineers to overcome the challenges. It emphasizes the characteristics of the various components of a power system such as generation, transmission, distribution, protection and SCADA system. During normal operating conditions and disturbances, the acquired knowledge will pro- vide the engineers the ability to analyse the performance of the complex system and execute future improvement
上傳時間： 2020-06-07
上傳用戶：shancjb
Multisim官方示例Multisim仿真例程基礎電路范例135例合集:Chapter 1 - RLC CircuitsChapter 2 - DiodesChapter 3 - TransistorsChapter 4 - AmplifiersChapter 5 - OpampsChapter 6 - FiltersChapter 7 - Miscellaneous CircuitsFundamental Circuits.pdf004 Parallel DC Circuits.ms10005 Series-Parrallel DC Circuit.ms10006 Current Analysis.ms10007 Millmans Theorem 1.ms10008 Millmans Theorem 2.ms10009 Kirchhoff's Current Law.ms10010 Thevenin's Theorem.ms10011 Superposition Principle.ms10012 Nortons Theorem and Source Conversion.ms10013 AC Voltage Measurement.ms10014 Frequency response of the Series RL Network.ms10015 RL High and Low Pass Filter.ms10016 Frequency response of the Series RC Network.ms10017 RC High and Low Pass Filter.ms10019 Center-Tapped Full-Wave Rectifier.ms10020 Bridge Rectifier.ms10021 Capacitor-Input Rectifier Filter.ms10022 Diode Clipper (Limiter).ms10023 Diode Clipper.ms10024 Diode Clamper (DC Restorer).ms10025 Diode Voltage Doubler.ms10026 Zener Diode and Voltage Regulation 1.ms10027 Zener Diode and Voltage Regulation 2.ms10028 Zener Diode and Voltage Regulation 3.ms10105 TTL Inverter.ms10107 TTL Gate.ms10109 OR Gate Circuit.ms10111 Over-Damp Circuit.ms10113 Critical-Damp Circuit.ms10115 Series RLC Circuit 1.ms10117 Clapp Oscillator.ms10119 Differential Amplifier 1.ms10121 Differential Amplifier in Common Mode.ms10123 LC Oscillator with Unity Gain Buffer.ms10125 Notch Filter.ms10127 PNP Differential Pair.ms10129 Crossover Network.ms10131 Second-Order High-Pass Chebyshev Filter.ms10133 Third-Order High-Pass Chebyshev Filter.ms10135 Fifth-Order High-Pass Filter.ms10
標簽： multisim
上傳時間： 2021-10-27
上傳用戶：trh505
對某四輪獨立驅動電動汽車輪轂電機進行研究,設計一種永磁無刷直流電機控制器.以STM32F103RBT6芯片為基礎,對電機驅動電路、采樣電路和保護電路分別進行硬件設計與分析;同時,采用模塊化軟件設計方案,對該控制器的軟件系統進行升級.實驗驗證表明:所設計的電機控制器能使電機響應迅速、轉速穩定、無超調,且電動車動力輸出性能良好.A permanent magnet brushless direct current motor controller was designed by studying the hub motor of a four-wheel independent drive electric vehicle.Based on STM32 F103RBT6 chip,the hardware design and analysis of motor drive circuit,sampling circuit and protection circuit were carried out respectively.At the same time,modular software design scheme was adopted to upgrade the software system of the controller.Experimental results show that the designed motor controller can ensure the motor fast response,stable speed,no overshoot,and good power output performances.
上傳時間： 2022-03-26
上傳用戶：qingfengchizhu
隨著電磁閥在工業和日常應用的增多,其功耗越來越被人們所重視。通過對電磁閥驅動電路的研究,設計一套電磁閥節能驅動電路。不僅提高了電磁閥的響應時間,更重要的是降低了功耗,使電磁閥由工作在大電流狀態下,變成大電流啟動小電流維持的工作狀態。減少了由電流過大引起的電磁閥線圈過熱,增加了電磁閥的安全性。The power consumption of an electromagnetic valve is drawing increasingly more attentiori as it is widely used in industrial production and daily life. In this study, an energy - saving driving circuit of electromagnetic valves was designed. It can make an electromagnetic valve to start with a high current while work with a low current; thereby the power consumption can be reduced. Besides, it can shorten the response time of an electromagnetic valve and improve the security of the valve.
上傳時間： 2022-04-16
上傳用戶：
以STM32F103C8T6為核心,設計了無刷直流電機控制器硬件電路。電路主要包括IR2310構成的PWM驅動電路、IRF3808構成的逆變電路、增量式旋轉編碼構成的速度反饋電路。控制器具有CAN和RS232通信接口,可與計算機或PLC構成速度或位置伺服系統。利用由xPC目標搭建的半實物仿真平臺對PI參數進行整定。測試了控制器的速度伺服響應性能,給定速度為2400rpm時,控制器響應時間為0.32s。實驗結果表明,系統工作可靠,穩定性好,響應速度快,可以滿足上肢康復機器人的機械臂速度控制性能要求。The hardware circuit of Brushless DC motor controller is designed by taking STM32F103C8T6 as the core,which mainly includes PWM driving circuits made up of IR2310,inverter circuit formed by IRF3808,speed feedback circuit composed of incremental rotary encoder and so on.Speed servo control system or position servo control system can be composed of BLDM controller with computer or PLC through CAN communication interface or RS232 serial communication interface.By using the hardware in the loop simulation platform built by xPC target,the PI parameters are set up.The Speed servo response performance of the controller is tested.When the speed is 2 400 rpm,the response time of the controller is 0...
上傳時間： 2022-05-07
上傳用戶：
