修其善則為善人，修其惡則為惡人。—— 漢·揚(yáng)雄《法言·修身》
DSG-03-2B2A-A100-50油研電磁換向閥
油研 液壓閥 方向控制閥 YUKEN 電磁換向閥 閥門 電磁線圈
DSG-03-2B2A-A100-50 DSG-03-2B2A-A100-50油研方向控制閥
DSG-03-2B2A-A100-50 DSG-03-2B2A-A100-50油研方向控制閥
Yuken Oil Hydraulic Equipment
油研液壓設(shè)備
Directional Control Valves
方向控制閥
Solenoid Operated Directional Valves
電磁換向閥
3/8 Solenoid Operated Directional Valves, DSG-03 Series
DSG-03 系列電磁換向閥
電磁鐵等各處以新設(shè)計(jì)思想開發(fā)的劃時(shí)代的高壓、大流量電磁閥。采用濕式電磁鐵，壽命長(zhǎng)，噪聲低，無(wú)外部泄漏。
- 適應(yīng)多樣化需要的類型
  具備有兩種類型，選用zui適用的閥。
  ·標(biāo)準(zhǔn)型，高壓（31.5MPa），大流量（120L/min）。
  ·無(wú)沖擊型，有效地減小閥芯換向引起的噪聲和管道振動(dòng)。
- 穩(wěn)定性的工作
  高吸力、強(qiáng)力彈簧保證了污染工況下仍有良好的動(dòng)作穩(wěn)定性。
- 具備有符合各種標(biāo)準(zhǔn)的產(chǎn)品
  為對(duì)應(yīng)面向海外設(shè)備出口，可供應(yīng)UL/CSA認(rèn)定品和CE標(biāo)記產(chǎn)品。
標(biāo)準(zhǔn)型
DSG-03-3C*-*-50
DSG-03-2D2-*-50
DSG-03-2B*-*-50
流量至 120L/min
壓力至 31.5MPa（僅對(duì)閥芯“60”型）/25MPa
回油管允許背壓：16MPa
zui高換向頻率：240min-1（僅對(duì)R型電磁鐵）/120min-1
無(wú)沖擊型
S-DSG-03-3C*-*-50
S-DSG-03-2B2-*-50
流量至 120L/min
壓力至 25MPa
回油管允許背壓：16MPa
zui高換向頻率：120min-1
油研 液壓閥 方向控制閥 YUKEN 電磁換向閥 閥門 電磁線圈
DSG-03-2B2A-A100-50 DSG-03-2B2A-A100-50油研方向控制閥
DSG-03-2B2A-A100-50 DSG-03-2B2A-A100-50油研方向控制閥
供應(yīng)商信息：武漢億嘉隆機(jī)電設(shè)備有限公司
Attn：袁榮
：

：
：
凡人之性成于習(xí)。圣人教以率之，法以治之，天下古今之風(fēng)以善為歸，以惡為禁久矣。—— 明·王廷相《答薛君采論性書》
DSG-03-2B2A-A100-50油研電磁換向閥
油研 液壓閥 方向控制閥 YUKEN 電磁換向閥 閥門 電磁線圈 液壓設(shè)備 電磁閥
Yuken Oil Hydraulic Equipment
油研液壓設(shè)備
Directional Control Valves
方向控制閥
Solenoid Operated Directional Valves
電磁換向閥
3/8 Solenoid Operated Directional Valves, DSG-03 Series
DSG-03 系列電磁換向閥
型號(hào)說(shuō)明
"S-DSG-03-2B2A-D24-C-N-50-L"
"S"--類型：
  無(wú)記號(hào) = 標(biāo)準(zhǔn)型
  S = 無(wú)沖擊型
"DSG"--系列號(hào)：
  DSG = 電磁換向閥（底板安裝型）
"03"--規(guī)格：03
"2"--閥位數(shù)：3,2
"B"--閥芯彈簧布置：
  C = 彈簧回中
  D = 無(wú)彈簧定位
  B = 彈簧復(fù)位
"2"--閥芯型式：2,3,4,8,40,5,60,9,10,11,12
"A"--僅使用中間位置和旁側(cè)位置的閥才標(biāo)記：
  A = 中位和電磁鐵a通電位置
  B = 中位和電磁鐵b通電位置
"D24"--線圈類型：
  交流：A100，A120，A200，A240
  直流：D12, D24，D100
  交流（交直整流型）：R110, R220
  交流（交直整流快速返回型）：RQ100
"C"--手動(dòng)操縱型式：
  無(wú)標(biāo)記 = 手操縱推桿
  C = 按鈕鎖緊（任選）
"N"--電氣連接型式：
  無(wú)標(biāo)記 = 接線盒型
  N = DIN插頭型（任選）
  N1 = DIN帶通電指示燈插頭型（任選）
"50"--設(shè)計(jì)號(hào)
"L"--電磁鐵反裝型：
  L = 僅電磁鐵反裝時(shí)標(biāo)記

YUKEN油研油液設(shè)備
電磁閥 方向控制閥
電磁換向閥 閥門 液壓閥
DSG-03-2B2-A240-50
DSG-03-2B2-A100-50
DSG-03-2B2-D24-50
DSG-03-2B2-A220-50
DSG-03-2B2-A110-50
DSG-03-2B3-A240-50
DSG-03-2B3-A100-50
DSG-03-2B3-D24-50
DSG-03-2B3-A220-50
DSG-03-2B3-A110-50
DSG-03-2B2B-A240-50
DSG-03-2B2B-A100-50
DSG-03-2B2B-D24-50
DSG-03-2B2B-A220-50
DSG-03-2B2B-A110-50
DSG-03-2B2A-A240-50
DSG-03-2B2A-A100-50
DSG-03-2B2A-D24-50
DSG-03-2B2A-A220-50
DSG-03-2B2A-A110-50
DSG-03-2B3B-A240-50
DSG-03-2B3B-A100-50
DSG-03-2B3B-D24-50
DSG-03-2B3B-A220-50
DSG-03-2B3B-A110-50
DSG-03-2B60B-A240-50
DSG-03-2B60B-A100-50
DSG-03-2B60B-D24-50
DSG-03-2B60B-A220-50
DSG-03-2B60B-A110-50
DSG-03-2B4A-A240-50
DSG-03-2B4A-A100-50
DSG-03-2B4A-D24-50
DSG-03-2B4A-A220-50
DSG-03-2B4A-A110-50
DSG-03-2D2-A240-50
DSG-03-2D2-A100-50
DSG-03-2D2-D24-50
DSG-03-2D2-A220-50
DSG-03-2D2-A110-50
DSG-03-3C2-A240-50
DSG-03-3C2-A100-50
DSG-03-3C2-D24-50
DSG-03-3C2-A220-50
DSG-03-3C2-A110-50
DSG-03-3C3-A240-50
DSG-03-3C3-A100-50
DSG-03-3C3-D24-50
DSG-03-3C3-A220-50
DSG-03-3C3-A110-50
DSG-03-3C4-A240-50
DSG-03-3C4-A100-50
DSG-03-3C4-D24-50
DSG-03-3C4-A220-50
DSG-03-3C4-A110-50
DSG-03-3C60-A240-50
DSG-03-3C60-A100-50
DSG-03-3C60-D24-50
DSG-03-3C60-A220-50
DSG-03-3C60-A110-50
DSG-03-3C9-A240-50
DSG-03-3C9-A100-50
DSG-03-3C9-D24-50
DSG-03-3C9-A220-50
DSG-03-3C9-A110-50
DSG-03-3C10-A240-50
DSG-03-3C10-A100-50
DSG-03-3C10-D24-50
DSG-03-3C10-A220-50
DSG-03-3C10-A110-50
DSG-03-3C12-A240-50
DSG-03-3C12-A100-50
DSG-03-3C12-D24-50
DSG-03-3C12-A220-50
DSG-03-3C12-A110-50

……

水性雖能流，不導(dǎo)則不通；人性雖能智達(dá)，不教則不達(dá)。—— 唐·馬總《意林·成敗志》

油研 液壓閥 方向控制閥 YUKEN 電磁換向閥 閥門 電磁線圈 液壓設(shè)備 電磁閥
Yuken Oil Hydraulic Equipment
油研液壓設(shè)備
Directional Control Valves
方向控制閥
Solenoid Operated Directional Valves
電磁換向閥
3/8 Solenoid Operated Directional Valves, DSG-03 Series
DSG-03 系列電磁換向閥
型號(hào)列舉
DSG-03-3C2-D24-50
DSG-03-3C4-D24-50
DSG-03-2B2-D24-N1-50
DSG-03-2B8-D24-N1-50
DSG-03-2B3-D24-N1-50
DSG-03-2B2-D24-50
DSG-03-3C4-A110-50
DSG-03-3C4-A220-N1-50
DSG-03-3C60-D24-N1-50
DSG-03-3C12-D24-50
DSG-03-2B2-A110-N1-50
DSG-03-2B3B-D24-50
DSG-03-3C9-D24-N1-50
DSG-03-2B8-D24-50
DSG-03-3C40-D24-N1-50
DSG-03-3C10-D24-50
DSG-03-2B2B-D24-N1-50
DSG-03-3C2-D24-N1-50
DSG-03-3C4-D24-N1-50
DSG-03-3C2-D24-50
DSG-03-3C4-D24-50
DSG-03-3C2-A220-N1-50HZ-50
DSG-03-2B3-D24-N1-50
DSG-03-3C11-D24-N1-50
DSG-03-3C12-D24-T-N1-50
DSG-03-2B2-D24-N1-50-L
DSG-03-3C2-R220-50
DSG-03-3C4-A200-70
DSG-03-2B10B-D24-N1-50
DSG-03-3C12-D24-N1-50
DSG-03-2B2-D24-50
DSG-03-3C4-A110-50
DSG-03-2D2-D24-N1-50
DSG-03-2B2-T-D24-N1-50-L
DSG-03-3C40-D24-N-50
DSG-03-2B8-D24-N-50
DSG-03-3C10-D24-N1-50
DSG-03-3C2-A110-50
DSG-03-3C4-A220-N1-50
DSG-03-2B2-A220-N1-50
DSG-03-3C3-A220-N1-50
DSG-03-3C60-D24-N1-50
DSG-03-3C60-A220-N1-50
DSG-03-2B8-D24-N1-50-L
DSG-03-2B2-A220-50-50HZ
DSG-03-3C4-A220-50-50HZ
DSG-03-2B2-A110-50
DSG-03-2B3-D24-N1-50-L
DSG-03-3C12-D24-50
DSG-03-3C40-D24-50
DSG-03-2B10B-D24-50
DSG-03-2B2B-D24-50
DSG-03-3C60-A220-50
DSG-03-3C60-D24-N-50
DSG-03-2B2-A110-N1-50
DSG-03-2B3-D24-50
DSG-03-2B3B-D24-50
DSG-03-2B2B-D24-N1-50L
DSG-03-3C9-D24-N1-50
DSG-03-2B8-D24-50
DSG-03-3C2-A220-N-50
DSG-03-2B2-A220-N-50
DSG-03-3C2-D24-N-50(含密封圈)
DSG-03-3C60-D24-50
DSG-03-2B12B-D24-50
DSG-03-3C3-A110-50-50HZ
DSG-03-2B2B-A220-N1-50
DSG-03-2B3B-D24-N1-50
DSG-03-2B8-A220-50
DSG-03-3C60-R220-50
DSG-03-3C40-A220-50
DSG-03-3C60-A110-50
DSG-03-3C40-D24-N1-50
DSG-03-2B60B-D24-N1-50
DSG-03-2B3B-A220-50
DSG-03-3C12-A220-N1-50
DSG-03-2B2B-A220-50
DSG-03-2B3B-A220-N1-50
DSG-03-2B2A-A110-50
DSG-03-3C8-D24-N1-50
DSG-03-3C10-R220-50
DSG-03-3C11-A220-50
DSG-03-3C60-R110-N1-50
DSG-03-2D2-A220-N1-50
DSG-03-3C2-R110-50
DSG-03-3C4-R110-50
DSG-03-2B2-D24-N1-50
DSG-03-2B3-D24-N1-50
DSG-03-3C2-D24-N1-50
DSG-03-3C4-D24-N1-50
……
性惡之人，亦不稟天善性，得圣人之教，志行變化。—— 漢·王充《論衡·率性》
YUKEN油研液壓設(shè)備 閥門
方向控制閥 電磁閥 液壓閥
DSG-01 系列電磁換向閥
型號(hào)列舉
DSG-01-2B2-A100-70
DSG-01-2B2-A100-70-L
DSG-01-2B2-A100-N-70
DSG-01-2B2-A100-N1-70
DSG-01-2B2-A100-70
DSG-01-2B2-A120-70
DSG-01-2B2-A120-70-L
DSG-01-2B2-A120-C-70
DSG-01-2B2-A120-C-N-70
DSG-01-2B2-A120-C-N1-70
DSG-01-2B2-A120-N-70
DSG-01-2B2-A120-N-70-L
DSG-01-2B2-A120-N1-70
DSG-01-2B2-A200-70
DSG-01-2B2-A200-N-70
DSG-01-2B2-A200-N1-70
DSG-01-2B2-A240-70
DSG-01-2B2-A240-70-L
DSG-01-2B2-A240-N-70
DSG-01-2B2-A240-N1-70
DSG-01-2B2-D100-70
DSG-01-2B2-D110-70
DSG-01-2B2-D12-70
DSG-01-2B2-D12-70-L
DSG-01-2B2-D12-C-N-70
DSG-01-2B2-D12-C-N1-70
DSG-01-2B2-D12-D-70
DSG-01-2B2-D12-D1-70
DSG-01-2B2-D12-N-70
DSG-01-2B2-D12-N-70-L
DSG-01-2B2-D12-N1-70-L
DSG-01-2B2-D24-70
DSG-01-2B2-D24-70-L
DSG-01-2B2-D24-70
DSG-01-2B2-D24-70-L
DSG-01-2B2-D24-C-N-70
DSG-01-2B2-D24-C-N1-70
DSG-01-2B2-D24-D-70
DSG-01-2B2-D24-N-70
DSG-01-2B2-D24-N-70-L
DSG-01-2B2-D24-N-70-L
DSG-01-2B2-D24-N1-70
DSG-01-2B2-D24-N1-70-L
DSG-01-2B2-D48-N1-70
DSG-01-2B2-R100-70
DSG-01-2B2-R100-70-L
DSG-01-2B2-R200-70
DSG-01-2B2-R200-N-70
DSG-01-2B2-R220-70
DSG-01-2B3-A100-70
DSG-01-2B3-A120-70
DSG-01-2B3-A120-70-L
DSG-01-2B3-A120-N-70
DSG-01-2B3-A120-N-70-L
DSG-01-2B3-A120-N1-70
DSG-01-2B3-A200-70
DSG-01-2B3-A200-70-L
DSG-01-2B3-A200-N-70
DSG-01-2B3-A240-70
DSG-01-2B3-A240-70-L
DSG-01-2B3-A240-N-70
DSG-01-2B3-D110-N-70
DSG-01-2B3-D12-70
DSG-01-2B3-D12-N-70
DSG-01-2B3-D12-N-70-L
DSG-01-2B3-D12-N1-70
DSG-01-2B3-D12-P-70
DSG-01-2B3-D24-70
DSG-01-2B3-D24-70-L
DSG-01-2B3-D24-C-N-70
DSG-01-2B3-D24-D-70
DSG-01-2B3-D24-N-70
DSG-01-2B3-D24-N-70-L
DSG-01-2B3-D24-N1-70
DSG-01-2B3-R100-70
DSG-01-2B3-R200-N-70-L
DSG-01-2B8-A100-70
DSG-01-2B8-A120-70
DSG-01-2B8-A120-N-70
DSG-01-2B8-A240-N-70
DSG-01-2B8-A240-N-70-L
DSG-01-2B8-D12-70
DSG-01-2B8-D12-N-70
DSG-01-2B8-D24-70
DSG-01-2B8-D24-N-70
DSG-01-2B8-D24-N-70-L
DSG-01-3C2-A100-70
DSG-01-3C2-A100-C-70
DSG-01-3C2-A100-N-70
DSG-01-3C2-A100-N1-70
DSG-01-3C2-A120-70
DSG-01-3C2-A120-C-N-70
DSG-01-3C2-A120-C-N1-70
DSG-01-3C2-A120-N-70
DSG-01-3C2-A120-N1-70
DSG-01-3C2-A120-P-N-70
DSG-01-3C2-A200-70
DSG-01-3C2-A200-N-70
DSG-01-3C2-A240-70
DSG-01-3C2-A240-N-70
DSG-01-3C2-A240-N1-70
DSG-01-3C2-D100-70
DSG-01-3C2-D100-N-70
DSG-01-3C2-D12-70
DSG-01-3C2-D12-C-70
DSG-01-3C2-D12-C-N-70
DSG-01-3C2-D12-D-70
DSG-01-3C2-D12-D1-70
DSG-01-3C2-D12-N-70
DSG-01-3C2-D12-N1-70
DSG-01-3C2-D12-P-70
DSG-01-3C2-D12-P-N-70
DSG-01-3C2-D24-70
DSG-01-3C2-D24-C-N-70
DSG-01-3C2-D24-C-N1-70
DSG-01-3C2-D24-D-70
DSG-01-3C2-D24-N-70
DSG-01-3C2-D24-N-P-70
DSG-01-3C2-D24-N1-70
DSG-01-3C2-D24-N1-P-70
DSG-01-3C2-D48-70
DSG-01-3C2-D48-C-70
DSG-01-3C2-D48-C-N-70
DSG-01-3C2-D48-N-70
DSG-01-3C2-R100-70
DSG-01-3C2-R100-N-70
DSG-01-3C2-0-N-70
DSG-01-3C2-0-N1-70
DSG-01-3C3-A100-70
DSG-01-3C3-A100-N-70
DSG-01-3C3-A100-N1-70
DSG-01-3C3-A120-70
DSG-01-3C3-A120-N-70
DSG-01-3C3-A120-N1-70
DSG-01-3C3-A200-70
DSG-01-3C3-A200-N-70
DSG-01-3C3-A240-70
DSG-01-3C3-A240-N-70
DSG-01-3C3-D110-70
DSG-01-3C3-D12-70
DSG-01-3C3-D12-C-N-70
DSG-01-3C3-D12-D-70
DSG-01-3C3-D12-D1-70
DSG-01-3C3-D12-N-70
DSG-01-3C3-D12-N1-70
DSG-01-3C3-D24-70
DSG-01-3C3-D24-D-70
DSG-01-3C3-D24-N-70
DSG-01-3C3-D24-N1-70
DSG-01-3C3-D24-P-N-70
DSG-01-3C3-D48-N-70
DSG-01-3C3-R100-70
DSG-01-3C4-A100-70
DSG-01-3C4-A100-C-N-70
DSG-01-3C4-A100-N-70
DSG-01-3C4-A100-N1-70
DSG-01-3C4-A100-P10-70
DSG-01-3C4-A120-70
DSG-01-3C4-A120-70-L
DSG-01-3C4-A120-C-70
DSG-01-3C4-A120-C-N-70
DSG-01-3C4-A120-C-N1-70
DSG-01-3C4-A120-N-70
DSG-01-3C4-A120-N1-70
DSG-01-3C4-A120-P-70
DSG-01-3C4-A120-P-N-70
DSG-01-3C4-A120-P8-70
DSG-01-3C4-A200-70
DSG-01-3C4-A200-N-70
DSG-01-3C4-A240-70
DSG-01-3C4-A240-C-N-70
DSG-01-3C4-A240-N-70
DSG-01-3C4-A240-N1-70
DSG-01-3C4-D100-70
DSG-01-3C4-D100-N1-70
DSG-01-3C4-D110-70
DSG-01-3C4-D12-70
DSG-01-3C4-D12-C-70
DSG-01-3C4-D12-C-D1-70
DSG-01-3C4-D12-C-N-70
DSG-01-3C4-D12-C-N1-70
DSG-01-3C4-D12-D-70
DSG-01-3C4-D12-D1-70
DSG-01-3C4-D12-N-70
DSG-01-3C4-D12-N1-70
DSG-01-3C4-D12-P-70
DSG-01-3C4-D12-P-N-70
DSG-01-3C4-D24-70
DSG-01-3C4-D24-C-70
DSG-01-3C4-D24-C-N-70
DSG-01-3C4-D24-D-70
DSG-01-3C4-D24-N-70
DSG-01-3C4-D24-N1-70
DSG-01-3C4-D24-P-70
DSG-01-3C4-D24-P-N-70
DSG-01-3C4-D48-N-70
DSG-01-3C4-D48-N1-70
DSG-01-3C4-R100-70
DSG-01-2D2-A100-70
DSG-01-2D2-A100-N-70
DSG-01-2D2-A100-N1-70
DSG-01-2D2-A120-70
DSG-01-2D2-A120-C-N1-70
DSG-01-2D2-A120-N-70
DSG-01-2D2-A120-N1-70
DSG-01-2D2-A200-70
DSG-01-2D2-A240-70
DSG-01-2D2-A240-N-70
DSG-01-2D2-D100-70
DSG-01-2D2-D100-N-70
DSG-01-2D2-D100-N1-70
DSG-01-2D2-D110-70
DSG-01-2D2-D12-70
DSG-01-2D2-D12-C-N-70
DSG-01-2D2-D12-D-70
DSG-01-2D2-D12-N-70
DSG-01-2D2-D12-N1-70
DSG-01-2D2-D24-70
DSG-01-2D2-D24-C-N-70
DSG-01-2D2-D24-D-70
DSG-01-2D2-D24-N-70
DSG-01-2D2-D24-N1-70
DSG-01-2D2-D110-N1-70
DSG-01-2D2-D48-N-70
DSG-01-2D2-D48-N1-70
DSG-01-2D2-R100-70
DSG-01-2D2-R100-N-70
……
天命之謂性，率性之謂道，修道之謂教。—— 《禮記·中庸》
YUKEN 油研 中國(guó)臺(tái)灣油研
液壓閥 方向控制閥 閥門
DSGL-01型電磁換向閥
型號(hào)列舉
DSGL-01-2B2-A110-50
DSGL-01-3C4-D24-60
DSGL-01-3C4-A220-N1-60
DSGL-01-2B2-D24-50
DSGL-01-2B2-A110-N1-60
DSGL-01-2D2-A110-60
DSGL-01-3C2-A110-N1-60
DSGL-01-3C2-A110-50
DSGL-01-2B2-D24-N1-60
DSGL-01-2D2-D24-N1-60
DSGL-01-3C4-D24-N1-60
DSGL-01-3C2-A110-N1-60-50Hz
DSGL-01-2D2-A110-60T
DSGL-01-3C4-A110-N1-60-50HZ
DSGL-01-3C9-D24-60T
DSGL-01-3C9-A110-N1-60
DSGL-01-2B3-D24-60
DSGL-01-3C12-D24-N-60T
DSGL-01-3C12-A110-N-60
DSGL-01-3C10-D24-60
DSGL-01-2B2-A110-50
DSGL-01-3C4-D24-60
DSGL-01-3C4-A220-N1-60
DSGL-01-2B2-D24-50
DSGL-01-2B3-D24-60
DSGL-01-2B2-A110-N1-60
DSGL-01-2D2-A110-60
DSGL-01-3C2-A110-N1-60
DSGL-01-3C2-A110-50
DSGL-01-2B2-D24-N1-60
DSGL-01-2D2-D24-N1-60
DSGL-01-3C4-D24-N1-60

DSGS-01 帶監(jiān)視開關(guān)型電磁換向閥
DSGS-01-3C2-D24-SWP1C-50T
DSGS-01-3C4-D24-SWP1C-50T
DSGS-01-3C60-D24-SWP1C-50T
DSGS-01-3C12-D24-SWP1C-50T
DSGS-01-3C9-D24-SWP1C-50T
DSGS-01-3C3-D24-SWP1C-50T
DSGS-01-2D2-D24-SWP1C-50T
DSGS-01-3C40-D24-SWP1C-50T
DSGS-01-3C3-D24-SWP1C-50T
DSGS-01-2B2-D24-SWP1C-50T
DSGS-01-2B3-D24-SWP1C-50T
DSGS-01-2B8-D24-SWP1C-50T

DSGS-03 帶監(jiān)視開關(guān)型電磁換向閥
DSGS-03-3C2-D24-SWP1C-50T
DSGS-03-3C4-D24-SWP1C-50T
DSGS-03-3C60-D24-SWP1C-50T
DSGS-03-3C12-D24-SWP1C-50T
DSGS-03-3C9-D24-SWP1C-50T
DSGS-03-3C3-D24-SWP1C-50T
DSGS-03-2D2-D24-SWP1C-50T
DSGS-03-3C40-D24-SWP1C-50T
DSGS-03-3C3-D24-SWP1C-50T
DSGS-03-2B2-D24-SWP1C-50T
DSGS-03-2B3-D24-SWP1C-50T
DSGS-03-2B8-D24-SWP1C-50T
……
生而知之者寡矣；學(xué)而知之者眾矣。—— 漢·荀悅《申鑒·雜言》